Bulletin 1 0 5

DEPARTMENT OF THE INTERIOR

RA KL K . LA E S E C R E T A R Y F N IN N ,

BUREAU OF MI N ES

V A N . H . M A G D I R E C T OR NNIN .

BLAC K DAMP IN MINES

L E G . A . B URRE L, 1 . w. ROB RTSON

AND

G . G . OB ERFELL

W AS HING TON G OV ERNM ENT PRINTING OFFICE 1 91 6 The B ureau of Min es in car in out one of the o isions of its or anic a — , ry g pr v g ct to b disseminate inform ation concerning investigations m ade prints a limited free edition li a ns o f each of its pub c tio . When this edition is exh auste co ies m a be o taine at cost rice onl thr o d , p y b d p y ugh m in in W hin n the Su e inten ent of Docum ents Gove n ent t O ce as to D . . p r d , r Pr g ffi , g , C Th in n n f D um ents not an O iC’ia l o th Bu au o M e Super te de t o oc 133 fl f e re f ines . n l an h h ul ba d e an e tire y separate office d e s o d e d r ess d :

E I TE D E T OF D O M E T SUP R N N N C U N S , Government P intin O ce r g fi , Wash n to D i g n, . C .

Th n al la unde hi h blications are ist i u te ohi its the i in of e ge er w r w c pu d r b d pr b g v g n n Th os f hi u li ation is m ore than one copy of a publication to o e perso . e c t o t s p b c

1 0 cents .

1 91 6 . C O N T E N T S .

I ntroduction Com parison o fatm ospheric air with mi ne air Composition ofthe atm osphere Transfer o f oxygen and carbon di oxide in breathing Effects on m an o fvariations in composition and am ount ofair Effect o f carbon dio xide

Effect o fdiminished o xygen s upply . Effect of air at high altitu des E ct o fbreathin a ec eas in ox en su l ffe g d r g yg pp y Effect of a mi ne atm osphere low in o xygen Effect o f atm ospheres low in oxygen on canaries and mice General com m ents on tests Effects o f o xygen deficiency as showing relative value of birds and mice in explo ring mines Effect o ftemperature and m oisture on m an

ila ion o fbuildin s a o e roun . Vent t g b v g d Ventilation conditions in mines Action of oxygen on coal i n at of abso tion of o x l I nflu nc of m o sture o e en bcoa e e r rp yg y f x n an d o uction of ca bon dioxid Abso tion o o e e om atm os h rp yg pr d r fr p eric air bwood y Discus sion of r esults E ect o f lowe in ox en and ai si n car on dioxide content on ex losibilit ff r g yg r g b p y o fm ethane-air mi xtures

m i n o f o x n and oduction o f carbon i xi ons u t o e o de bm en and b C p yg pr d y y

Foulin ofmin e air beca oftim e g y d y b r i i f la Specific gravity and compos t on o b ck damp . E ct on li hts of air low in ox en and hi h in ca bon di xi ffe g yg g r o de Effect of atm ospheres low in o xygen on fires in mines l f l - m Results of ana yses o coa mine at ospheres . Results o fanalyses o fsam ples in series 1 Comm ent on analyses o fsamples in series 1 Tem perature and humidity R l f anal f am l i esu ts o yses o s p es in ser es 2 to 6 . Comm ent on r esults of sam pling and analysis Sam ples in s eries 2 Sam ples in se ries 3 Sam pl es in series 4 Sam ples inseries 5 Samples in series 6 Effects o ftem perature and humidity and othe r factors E ects o flea a e of air throu h oors rattices tc ff k g g d , b , e I nflamma ble as in mines g TE TS 4 CON N .

Occurrence and composition o f gas in r oc k strata o f the Cripple Creek gold minin dis t ict olo ado g r , C r Origin o fthe strata gas

ts o fba om et ic ressure on outflow o f st ata as . Effec r r p r g Collection ofsampl es ofgas in four m etal mines

Observations on gas in Midget mine . l ations a din aseous conditions in Ana n mi n a obse e co da ne . Ge er rv r g r g g Observations on gas in Cresson mine Tabulated data Special air samples from Mary McKinney mi ne i i n o f st ata as sam les c al culated on air- ee basis Compos t o r g p fr Effect on m en o fpartial pr essures o f o xyg n th indi ations af o d d ban l n l m a ison betwee e c e c e a d bacet n Co p r f r y d y y e e flam e and analyses ofthe sam pl es m us tibl e as i n the rock~s trata as Co b g g n tions o f 1 5 m tal mines as indicate banal ses o f air sam Ventilation co di e d y y pl es

Observations r egarding black damp in c ertain m etal mines

Summ ary . mthod f al 1 n ublications on mine accidents and e s o co m1 n P g I ndex B L A C K D A M P I N M I N E S .

R B ER S A D B E A RELL . T O E B Y . . UR . N . . R LL G B , I W O ON, G G F .

R D U INT O CTION .

u i in n The B reau of M nes , pursuing investigations looki g to greater in i f safety min ng , has analyzed samples of the air in many di ferent U coal mines in the nited States , and has studied the analyses . This report presents the results of one phase of this study and shows how a tmospheric air, after entering a coal mine , loses oxygen and gains s o — l carbon dioxide with resulting formation of cal ed black damp . Also the report discusses the effects of the constituents of black damp n and on men , on the bur ing of oil and acetylene lamps , on the ex

los ibilit . p y of methane The term “ black damp was and still is widely used to designate di fi accumulations of carbon oxide , but a more exact de nition of black E s ha s damp , as Haldane , the ngli h physiologist , pointed out, is an accum ul ation of carbon dioxide and nitrogen in proportions larger r i than those found in atmospheric air . The reasons for prefe r ng Hal ’ dane s definition are given on succeeding pages .

C R S S HE R C A I R WI H E A IR OMPA I ON OF ATMO P I T MIN .

h a a ir i W en tmospheric enters a coal m ne , it changes in composition according to ( 1 ) the velocity with which it traverses the workings ; 2 n i in — is ( ) the amou t of coal w th which it comes contact that , the extent of the mine workings that it tra verses ; (3 ) the gaseous nature o f the seam ; (4) the tendency of the coal to absorb oxygen ; and (5 ) n the temperature and wetness of the mi e . n fol As regards the details mentioned , the governi g conditions are as : 1 i lows ( ) Other th ngs being equal , more carbon dioxide and methane are present and there is a greater deficiency of oxygen at places where

air l i . 2 The the is sti l, as at working faces and in old work ngs ( ) purity air d in l of the epends on the distance it has traveled , so that a wel ventilated mine the air is purer at working faces near the shaft than il at those that are remote . In the same mine the air w l be fresher and pur er when the mine is ventilated by a split system than when a 3 the ir traverses each working face and entry . ( ) Some mines vary s r l greatly a rega ds the generation of methane . Methane is not on y 5 LA K D M I N M ES 6 B C A P IN .

i n dangerously inflammable , but, if ntroduced in large proportio s at r a some parts of a mine, it lowe s the oxygen content of the tmosphere to such an extent that the atmosphere will not support the combustion f difl of lamps or even will not support li e . (4) Coals er as regards A their power of absorbing oxygen . bsorption of oxygen is never accompanied by a molecular proportional increase in the amount of d t carbon ioxide produced , for the oxygen combines with cer ain uns aturated hydrocarbon compounds in the coal . (5 ) The amount ofwater vapor in air is principally a function of the temperature of the is rs i rri air ; hence , if air that comparatively dry ente a m ne , if the te erature is i p of the mine h gher than the outside temperature , and if the mine is comparatively wet, then the proportion of water vapor taken up by the mine air may be greatly in excess of that in the atmospheric air . In mines other than coal min es the chief factors that decrease the oxygen content of the mine air are the velocity of the air cur of n rent, the extent the workings traversed by the air, the amou t of i oxygen taken from the air, and the amount of carbon diox de or other ad suffocating gases ded to it by the decay of mine timbers , the burn i ing of lights , the breath of men and of animals , and the ox dation of

i . minerals, and also by the gases g ven off from the rocks penetrated

C S R OMPO ITION OF THE ATMO S PHE E .

dr Pure y air as analyzed contains , by volume , per cent of

i . oxygen, per cent of carbon diox de , and per cent of nitrogen — Included in the nitrogen content are the four inactive gases argon,

r . k y pton , neon , and xenon These , with the exception of argon , which e e air in d l constitut s per c nt of , are present excee ingly smal pro

. i portions Water vapor is also present in the air , vary ng greatly in ' difleren d f amount at t times and in i ferent places . The temperature of the air is the most important facto r in determining water-vapor content . Different analysts have found that pure air differs slightly in com fi u i wi the position from thbe g res g ven above , but these variations , th exception of car on dioxide , for which the occasional variation may 1 be one or two hundredths of per cent, are due to unavoidable in inaccuracies the analyses . Pure air has the same composition by volume at sea level or on mountain peaks or at heights that may be nl n reached o y with balloo s . This constancy of composition is b s brought about y a ga eous exchange between the plant and the ani ’ i r o fl mal l fe , because animals th ow carbon dioxide , whereas all the All higherforms of plant life absorb it . of the carbon dioxide of the living world comes from the per cent of carbon dioxide in the atmosphere . F AI R EFFECTS ON M A N OF VARIATIONS I N COM POSITION O . 7

R H TR ANS FE R OF O" YGEN A N D C ARB ON D IO" ID E I N B E AT ING .

the W air . hen a man breathes , enters the lungs The oxygen from i air passes through the delicate lining membrane of the a r cells of

“ the lungs into the blood , where it forms a loose chemical combination with the haemoglobin in the red corpuscles . Thus loosely combined the oxygen is conveyed to the heart , and thence through the arteries ll a to the capi aries , where it separates from the h emoglobin and l passes through the capill ary wa ls to the tissues , where it is con i sumed . Carbon dioxide passes from the tissues in a correspond ng

r h r manner, fo ms a loose combination (as bicarbonate and possibly ot e the compounds) in the blood and is conveyed by veins to the lungs , where the combinations break down , and the carbon dioxide passes from the lining membrane of the lungs into the breath .

E FFE CT S ON M A N OF VAR IATION S I N COMPO S ITION A N D AMOU NT

OF A I R .

E E FFEC T OF CAR B ON DIO" ID . As regards the amount of carbon dioxide present that may give rise to symptoms of poisoning , Haldane and Smith carried out a number of experiments on animals and men and demonstrated that these symptoms did not begin to appear till 3 to 4 per cent of the

. Men gas was present, when the breathing became slightly affected can , however, go on working for a considerable time in this atmos h ere w mf l p ithout feeling serious disco ort , although they will certain y become quickly fatigued , and great exertion will cause panting ; but Haldane kept animals for weeks in this atmosphere without causing 7 8 them much inconvenience . A proportion of to per cent causes 1 0 i more apparent symptoms , and with per cent the distress s great , oe the headache becomes much more severe , there is marked dyspn a, u throbbing pulse , and fl shing of the face , and the gas begins to have a

i . 1 2 1 5 stupefy ng effect With to per cent , cerebral symptoms appear , and the patient soon becom es unconscious . Death may take place s 2 5 after exposure for several hour to per cent , but Haldane found 5 0 that some animals may breathe a much greater percentage , even per cent , without dying . The concentration of c arbon dioxide in the lungs is automatically W regulated , so that it is remarkably constant , practically ithout rela i tion to changes in the rate of breathing , provided resp ration is not

' a H e S S L in P s o lo a efe s o f air v ate br iration: ou . Pa . al an . . and m o a es d , J , ith , r , hy i gic l f ct iti d y p J r th

act . B , vol . l , 1 892 , p . 1 74. ACK AM I N M ES 8 BL D P IN .

i forced . Th s relation was shown by experiments of Haldane and Pries tl a su : y , the re lts of which follow

o Haldane and P estl to determ ne elation betwe d Res ults of e xperiments f r y r en rapi ity of i i . a d concent ati o carbon di ox d ation n on i e t n lun respir r f gs .

Proportio n o f c arbon diox id e in a lveo lar air Respira on r Subject . ti s p e A t end end minute . At ofinspi ofexpi

at on . ration . r i

P r en P er ent. P er ent. e c t. c c

5 5 9 5 . 87 5 . 73 H ne S . a a I . ld 5 . 56 5 . 70 5 . 63

5 . 40

5 . 44 5 . 52

5 . 95 6 3 5

G . P i es J. r tly 5 . 98 6 . 0 9

Even during muscular exertion Haldane and Priestly found that when the percentage of carbon dioxide in the inspir ed air was increased to 4 or 5 per cent the partial pressure of t h e carbon dioxide n u in the air i the air cells of the l ngs was practically constant . The effect of breathing air containing carbon dioxide is to stimulate the s o -called respiratory center in the brain and in crease the depth ‘ of breathing . This increase in the depth of breathing is brought about by the smallest increase in the percentage of carbon dioxide f in the inspired air, and is suf icient to keep constant the percentage i ls i x n . of carbon dio ide in the alveol , or, air cel , of the lu gs Th s response of the respir atory center of the brain to carbon dioxide is seen during muscul ar work . The latter increases the production u of carbon dioxide in the arterial blood , resulting in an invol ntarily increased depth of breathin g proportionate to the extra production Of di ul n h r carbon oxide , hence there res ts the rapid breathi g ( ype p naaa ) seen during exercise . So small an amoun t of carbon dioxide in the atmosphere as 1 or 2 per cent does not materially endanger the li e fe and comfort of those who breathe it , but does decreas their m efficiency as work en . A man is forced to breathe a larger amount in i of air a given time , and this breath ng consumes energy just as the n work he is doing co sumes energy . An increase of 5 0 per cent in the amount of air breathed is brought

1 . 4 C O about by the presence of per cent 2 in the inspired air , according fi Schn eider to Douglas , Haldane, Henderson , and They add that panting then becomes excessive even if a man does a g reat deal less muscular work than he could do in normal air .

' a Ha ane J. S . and P es J. G . The e u a on of the un ven a on : Jour . P s o . vol . 3 2 1 90 5 ld , , ri tly , , r g l ti l g til ti hy i l , , , p b225 Hen e son Y . and n e E C P Ha an . S D ou as C . G . e . S e . . s o o a o se va ons ma e gl , , ld , J , d r , , ch id r , , hy i l gic l b r ti d - on P kes Pea C o o . : P i os . T ans . Ro . S oc. Lon on set . B vol . 20 3 e ua 1 91 3 . 220 221 . i k , l h l r y d , , , F br ry, , pp M S OF AI R EFFECTS ON M AN OF VARIATION S I N CO PO ITION . 9

L EFFECT OF DIM INISHED O" YG EN SUPP Y . Abnormally rapid breathing is also brought about by want of oxygen . In some individuals such breathing is produced when the oxygenpercentage of the air is less than 1 3 (normally about 2 1 ) per k cent . Rapid breathing is produced much more quic ly by excess of carbon dioxide than by a corresponding deficiency of oxygen . The important practical point to remember is that rapid breathing caused a by carbon dioxide starts long before d nger becomes serious , whereas when it is produced as the resul t of a deficiency of oxygen it is a n grave sym ptom and poi ts to serious danger . Bert ‘1 showed that the abnormal symptoms and dangers associated with low barometric pressure depend , not on the diminished mechan r the o ical pressure , but on the diminished partial pressu e of xygen and consequent imperfect aeration of the arterial blood with oxygen . He found that defin ite symptoms of want of oxygen began to appear whenever the partial pressur e of the oxygen was reduced below a r certain limit . Thus at ordinary atmospheric pressu e a cat died when the proportion of oxygen was reduced to about per cent , or a partial pressure of per cent of an atmosphere . At a barometric r pressu e of atmosphere , on the other hand , the animal died when 9 the oxygen was reduced to about per cent , which is again per cent of 2 an atmosphere , and at a pressure of atmospheres a reduction of the oxygen percentage to per cent was needed . He established the general law that the physiological action of a gas depends on its al parti pressure , and further showed that the percentage by volume of oxygen taken up by the blood either in the lungs or outside the u body depends on the partial press re of the oxygen , and is greatly reduced when the lowering of oxygen pressure becomes dangerous . W hen men or animals , even though at rest , are subjected to atmos heres fi in u oe p de cient oxygen or at low press res , marked hyp erpn a is rapidly produced . Marked hyperpn oea caused by oxygen want is only temporary , and is due to the fact that the want aids carbon dioxide in exciting the respiratory centerf’ For a short time the proportion of carbon dioxide already present in the blood and tissues e h is more than nough to excite the center . W en the excess has been eliminated by a temporary hyperpnoea the breathing again becomes x th quiet , and if the transition to want of o ygen is gradual e tem o rar oe p y marked hyperpn a is not noticed . Want of oxygen without l 6 the aid of carbon dioxide does not excite the respiratory center at al .

a B Pa L m e u a ess on a o é t ue 1 878 . brt , l , pr i b r riq , Ha an I . d Pou on E P E f e . S an . . e s of wan o f ox en on es a on : ou . P s o . vol . 3 7 ld , , lt , f ct t yg r pir ti J r hy i l , ,

1 90 8 . 3 90 . , p 0 Hen e son an e n a and s o A P oe : m . ou . s o . vol . 25 1 91 0 . 3 1 0 3 85 . d r , Y d ll , Ap h ck J r hy i l , , , pp , B LA K AM I N M ES 1 0 C D P IN .

E E T OF A I R A T HI G H ALT TU E FF C I D S .

i hi ” Men ascend to h gh altitudes where the air is t n , and conse quently the partial pressure of the oxygen as compared with that at sea level is small . Under the same conditions of temperature and i pressure the expansion of d fferent gases is practically the same .

Hence the proportion by volume of oxygen , nitrogen , etc . , in air remains the same , no matter what the altitude , but the percentage by weight varies as the pressure changes . Air at sea level and at a

760 mm . i 2 barometric pressure of conta ns , by weight , about 3 per 3 mm cent of oxygen , but at half that pressure , or 80 . , contains only

2 3 . half of per cent , or per cent The table foll owing S hows the barometric pressur es at different al — heights, also the parti pressure of the oxygen that is , the per centage of oxygen that would correspond to the same attenuation of air at sea level .

' ' es o o en co es ondin t dt rent bar m Pa tia l essu x o e o etric essu es r pr r f yg rr p g fi pr r .

u e Altit d . B aro I nches o f m etric me u essu e rc ry . pr r , Me e s ee mm ofH t r . F t . . g .

’ D e d Abru zzi his In explorations of the Himalayas the u and im companions cl bed to a height of feet , the barometric pres

3 1 2 . 8 sure being mm , and the partial pressure of the oxygen about “ m i per cent . At this point the explorers felt no disco fort dur ng rest and seemingly did not experience any difficulty in performing the work required in climbing . l However , after the exp orers had lived for several weeks at a height of feet above sea level , the atmosphere did work some harm ul l in f effects , revealed only gradua ly a slow decrease of appetite m and consequent lack of nourish ent , but without any disturbance of f digestion . Of course , ultimately this insuf icient nourishment would l have caused a lowering of vita ity , loss of flesh , and a certain amount

'

a . S of an emia However , the effect was so low that even at the end of two months the men were able to make long marches without becoming excessively tired .

a D i o e K a o m n w n H m a a 1 61 - 8 d a a a d es e a 90 9 . 3 3 6 . Filippi, Filipp , r k r t r i l y , , pp I N M S OF AI R EFFEC TS ON M A N OF VARIATION S CO PO ITION . 1 1

E Many people are affected at a height of to feet . very m body suffers fro shortness of breath and fatigue at feet , and At serious symptoms frequently develop at feet . this height the partial pressure of the oxygen corresponds to air at sea level containing about per cent oxygen . However , people can live ru at very high altitudes . In Pe , Bolivia , and northern Chile a large proportion of the population live above feet . The elevation

El in . of the observatory at Mista , the Andes , is about feet a ttenu It takes time , however , for the body to adapt itself to such an h m ation of t e air . A person unaccusto ed to it and suddenly plunged into such an atmosphere would experience severe distress .

T E ATH E REA S G " YG E S U P PL EFFE C OF B R ING A D C IN O N Y .

i in Some instructive experiments on this po nt , which one of the 1 22 “ authors participated , are described in Technical Paper and summarized in Technical Paper The experiments were made Y under the direction of andell Henderson , professor of physiology at

Yale University . A man breathed airin and out of a bag having a capacity of about

70 liters . By means of a can of caustic potash inserted between the ’ man s mouth and the bag the exhaled carbon dioxide was removed . U di r nder these con tions , of cou se , the oxygen content of the air it breathed gradually fell . When had fallen to about 7 per cent the subject lost consciousness for a few seconds .

The mode of action of the oxygen want is instructive . The l subject felt no urgent. warning symptoms up to the time of col apse .

In fact, he wanted to continue , and just before collapse made a show of resistance against discontinuing the experiment . He felt no real distress until some time after the experiment . The next day he was decidedl y unwell .

E E T OF A M E ATM S HERE LO I xYG E FF C IN O P W N O N . In its insidious action oxygen want acts as carbon monoxide frequently does, that is , when the oxygen is slowly decreased . One difficul ty in comparing the mode of action of the two lies in the scarcity of experimental data regarding the effects on men of atmospheres containing small percentages of oxygen . Much light is thrown on the action of the two gases by an accident 0 u fi E . that occ rred in the Lodge Mill Colliery , Hudders eld , ngland

a B u e G . A . and O e e G . G . E fe ts ofa mos e es e en in ox en on sma an ma s and rr ll , , b rf ll , , f c t ph r d fici t yg ll i l — men Te . Pa e 2 B on : 1 2 u eau ofMines 1 91 5 . 7 9 . b ch p r , r , , pp B u e G . A . and O e e G . G . C om os on ofna ura as use in 25 es wi a s uss on o fthe rr ll , , b rf ll , , p iti t l g d citi , th di c i o ert P M — es of na u a as : Te . a e 1 0 9 B u eau of ines 1 91 5 . 1 6 1 8. pr p i t r l g ch p r , r , , pp 0 L o . D . Th e use of es ue a aratus at Lod e M Co e Hu e s e : C o . G ua d vol . 1 0 6 l yd , W , r c pp g ill lli ry , dd r fi ld ll r , ,

N ov. 7 1 91 3 . 957. , , p A AM N M E 1 2 B L C K D P I IN S .

Three men were in a disused part of the mine , and two of them ,

. . i A and B , were overcome by the black damp at a m A th rd ,

4 . . . C , was overcome at a m in an attempt to rescue his comrades At wi 1 p . m . of the same day rescuers equipped th breathing apparatus l removed C and about an hour later removed A . A ittle later B was B e th l found dead . A and C were in a critical condition but stil

hr . breathing . A died t ee days later The air in which the men were overcome contained a high percentage of methane and had a corre “ s o ndin l . p g y low oxygen content Haldane , in speaking of this wi : disaster, made the follo ng comment

in at that the m en e e m e bth in i All the facts recorded dic e w r e ov rco y e suffic ency a air h as no ason to sus e th in the oxygen per cent ge of the . T er e w re p ct e presence of fir r atin I n a dition the l as no obe o be . b a bon m onoxide as th e e w ood o f th c r r g g d , e dead m an as lac not red as it would have een if death had een du e to ca on w b k , , b b rb n xi I t is o a l e that sufficient fire am was esent to educe the ox en m o o de . pr b b d p pr r yg The act that A did not ecove was du e to exactl the sam e ca s to 7 o r 8 per cent . f r r y u e nt m n ecove in a te se e e ca on m onoxide oisonin T which often pr eve s e r r g f r v r rb p g . he l am a ed bthe olon e ex osu e to dea th f tissues have been seve e d o ox en r y g y pr g d p r r yg , g n s l is com letel esto ed ecove is oubt ul so that al thou h the ox e u . I n , yg pp y p y r r , r ry d f ost-m o tem exami natio n evealed the act that the hea t was dilat th e case of A the p r r f r ed . obabl the hea t m uscl es and the othe tissues we e in a condition of att de en Pr y r r r f y g i imil ti n a se bthe want o f o x en . The w te has seen othe s a cases f c ra o c u d y yg r r r r o dilatation sim ulatin seve e hea t disease and o nl sl owl eco e in a te olon ed g r r , y y r v r g f r pr g n xi oisonin So far as he is awa e howeve this is the e x osu e to ca on m o o de . p r rb p g r , r , o nl eco ded case o f death a te a tial ecove om e x osure to an atm os he e y r r , f r p r r ry , fr p p r whi ch was sim l de cient in o x en a a t om the esence o f ca on m onoxide p y fi yg , p r fr pr rb .

E FFE CT OF ATMO S PHE RE S L OW I N O" YGEN ON CANAR IES A N D

M I CE . Some experiments to determine the effect of atmospheres low in oxygen on mice and canaries, performed by thebauthors of this bul l etin n l 22 . , are described in Tech ical Paper In conducting the experiments , atmospheres containing various percentages of nitrogen 1 — and oxygen were prepared in 0 liter bell j ars . For the nitrogen supply a tank containing nitrogen with a small percentage of oxygen h was obtained . The atmosphere in t e tank analyzed per cent nitrogen and per cent oxygen . t In the experimen s with canaries three birds , designated A , B ,

. l : and C , were used Tabulated resu ts of the experiments follow

a — Hal ane J. S . N e D L . r W . . o C o G ua d vo l . 1 6 No v. 7 1 7 . d o on a e : 0 91 3 . 95 958 b , , t p p by l yd ll r , , , , pp B u e A . an e fi ct of a m os e e en in ox en on sm a an ma an G . d O e G . G . E e es s d rr ll , , b rf ll , , t ph r d fici t yg ll i l - m en: Te . a e 1 22 1 on P 1 9 5 . 5 6 . ch p r , , pp EFFEC T OF LAC K OF O" YGEN ON CANARIES A N D M ICE. 1 3

— o bat in atm os he es L 1 Results o ex e iments to dete mi ne e ect on canaries e h g p TAB E . f p r r fl f r r low i n oxygen .

m n . C omposition of atm os phere during experi e t

end e nnin . . n ana At b gi g At Effect o c ry .

Oxy N itro Oxy Nitro

n en . en . en . ge . g g g

P ct P ct. P . ci . P . ct. . . . mmediate s ess ev n 48 8. 5 0 90 . 90 e a 9. 42 90 . di tr i c d by r pid ea n 0 en and en en br thi g , bill , t d cy w n 1 m nu es h i to abble . 0 i t t e b rd was seemingly in normal condi tion ex cept for sli htly increased f n m rate o breathi g . gt was re oved om th e a m os e e after 1 u fr t ph r ho r . B ehaved similarly to canary B in 1 trial . Sh owed immediate distress by pant in and uns ea ness bu t not g t di , did collapse I t did not evince any m ore distress than canary B in 1 I was trial . t left in th e atmos h r f r u p e e o 1 ho r . n w 83 92. 0 7 C o a se as soo as as a e in 7. ll p d it l c d I th e atm osphere . t breat ed ve s ow W i e es and ose l ly , th y bill cl be ve e its ut r co r d normal state in less th an a m inute after it h ad been em ve to air r o d fresh . S owe s ess but not 7 1 0 92. 80 o a se h d di tr , did c ll p in 2 m nu e en ana 0 i t s . Wh c ry C was pl aced in th e atmosphere it mm e a e o a se i di t ly c ll p d .

The next experiments were made with white mice instead of

canaries . Tabulated results follow .

— Re u lts o ex e iments to determine e eet on white mice o atmos heres de cie t TAB LE 2 . s f p r fl f p fi n

i n oxygen .

C omposition of atm osphere d uring exp eriment .

nin end . At begin g . At Efiect on mouse .

P . ct. m f 2 S owed mme a e s m o s o s ess . 0 . 0 h i di t y pt di tr At times it appeared normal and again ap

ea u s . D id no t a I t wa red s l ggi h coll pse . s a 1 eft in the tmosphere hour . a a 1 0 S m e as on m ouse in tri l 1 . S ame as on mice in trials 1 and 2 . Showed imm ediate dis tress and collapsed in n m n u e a e em va m 6 m inutes . O e i t ft r r o l fro h a e wa t e tmosph re it s on its feet . C AM I N ” M N E 1 4 B LA K D P I S .

N R C OMM ENTS N TES S G E E AL O T .

Canaries show some distress in atmospheres containing per cent n n i in oxygen . The distress is more pronou ced in atmospheres co ta n g as low as or per cent , but even in an atmosphere containing as little as per cent of oxygen they may or may not collapse . i Mice are slightly more resistant to atmospheres low n oxygen . In an atmosphere containing about 7 per cent of oxygen they show some s i distress and become more or less luggish if left n it . One mouse resisted an atmosphere containing as little as per cent of oxygen before it collapsed . With that percentage , collapse did not occur 6 until the mouse had been exposed for minutes .

EFFE CTS OF O" YGE N D EFICIENCY A S S HOWING RE LATIVE VALU E F B I RD S A N D CE E" L O MI IN P ORING MINE S .

From the foregoing experiments on birds , mice , and men , it will be seen that oxygen want begins to affect men in about the same time as it does mice and canaries , and the percentages that cause ff n m f collapse are not much di erent . A i als di fer slightly as to their in in and resistance to collapse atmospheres low oxygen , presumably the s ame is true of men . The fact is evident that exploring parties in mines can not satisfactorily use birds and mice to detect atmos s phere low in oxygen . Canaries are of chief value in showing by their behavior the pres

. n ence of carbon monoxide Afterdamp may contai enough oxygen , o 1 7 an - ab ut per cent , to support the flame of oil fed lamp , so that exploring parties entering it would have no means of knowing that the air is low in oxygen , although the presence of dangerous percentages c of carbon monoxide could be dete ted by the action of the canaries, even

- ifit is not shownby the flame of the safetylamp . Wh en mine exploring parties , unequipped with breathing apparatus , reach an atmosphere in i which oil lamps are ext nguished , they are likely to proceed close to or into dangerous atmospheres if they advance farther , even if provided with canaries for detecting vitiated air . The acetylene lamp does not become extinguished until the proportion of oxygen falls to about 1 3 per cent . In such an atmosphere a party is not in immediate danger, although close at hand there may be atmospheres considerably lower hi s in oxygen , and hence dangerous , into w ch a per on might walk in a very short time . However, any party exploring a mine after a disaster and using canaries would also be equipped with oil safety n lamps and with electric lamps , so that acetylene lamps eed hardly be considered . VEN TILA TION OF BU ILDI NGS AB OVE GROUN D . 1 5

EFFE CT OF TE MPER ATURE A N D MOIS TURE ON MAN .

The temperature of the atmosphere is important in that it governs A the capacity of air for absorbing moisture . hot , moist atmosphere in prevents the evaporation of perspiration from the body . If , a ddition , hot , moist air is stationary, it becomes entangled between

k r . the clothing and s in , and becomes warmed to body temperatu e

Hence , the body can not lose heat to the air , and the skin becomes in warmed and bathed in perspiration . Putting a fan operation whirls the hot , warm air away from the body and allows cooler air fi to take its place , accounting for the bene cial effect of a fan in a - fin . room , even if fresh outside air is not ding access If the wet bulb ° 9 . temperature is 9 F (body temperature) , the body will not lose ° °

79 69 F . heat , but if the external temperature is or , perspiration E n - can evaporate . xperience has taught that whe the wet bulb ° n temperature exceeds 75 F . the amou t of work that a man can do V in r begins to fall off . entilating engineers this count y try to ar ° a — 2 range ventilating equipment so that wet bulb temperature of 7 F . will not be exceeded . They aim to maintain a relative humidity - varying between 3 0 and 80 per cent . The standard for dry bulb ° temperature is about 68 F . h l “ i En Cadman and W al ey , in an investigation of vent lation in g ° - 72 . lish coal mines , observed that at a wet bulb temperature of F ° heavy clothing was removed and only light clothing worn . At 80 F . hard work was possible , provided the maximum body surface was k exposed , the capacity for wor being greatly increased , however , if a

- current of air or a breeze passed over the body . With wet bulb ° ° s 80 85 . temperature of from to F work was seriously affected , and hard work was almost impossible .

VE NTILATION OF B U ILD INGS AB OVE GROU ND .

In designing the ventilation systems of public buildings , houses , and other places where people meet , the effects of carbon dioxide i and oxygen are subordinated to other cond tions , such as tempera

i . in ture, humidity, and keeping the air mov ng At sea level , the

- most ill ventilated room , the weight of the oxygen in a cubic foot of in n hi and the air never is as low as the ope air at gh altitudes , it is seldom that the carbon dioxide content rises above or per unfi cent, although the air in such a room may be t to breathe . The ventil ation in rooms is not essentially a matter of correcting diminished oxygen or increased carbon dioxide but of keeping the and of temperature , the relative moisture , the movement the air in a proper state . However , in the ventilation of rooms where people

a C a m an o n and a e E . B . Re o t of an in ui n o th e vent a on of oa m nes and d , J h , Wh ll y, p r q ry i t il ti c l i th e e o s ofexam nin for fire am : Ro a C ommiss on on M nes En an 1 90 9 4 m th d i g d p y l i i , gl d, , p . . P I N M I N ES 1 6 B LACK DAM . congregate the carbon dioxide and the oxygen tests may be excel 0 . lent criterions of the state of , ventilation Haldane and Osborne have investigated the ventilation of a large number of workshops and factories and have recommended that the standard of ventilation be such that the proportion of carbon dioxide does not exceed per cent during daylight or per cent after dark when oil or gas is ifi used for lighting . The carbon dioxide percentage is spec ed because its determination is easy and its presence a sign that there is no free ' c ventilation and that the air tends to be ome humid and warm . f However, the vitiation of air in overcrowded rooms may arise rom the products of disease , want of cleanliness of the occupants , or the room itself . In fact , air that , judged by the carbon dioxide standard , u fi is s f ciently pure , may be exceedingly impure when judged by the i number of microorganisms in it , and v ce versa . The test of smell, f in m of eeling of comfort or discomfort , breathing the air of a room ay i give resul ts equally at variance w th the carbonic acid test . Some i i people are more nfluenced by odor , others by an ncreased quantity of carbon dioxide or moistur e or an increased temperature . Men who habitually work in bad air that is not suffi ciently tainted f ae h to cause acute symptoms may suffer rom slight an mia , wit dis i nclination for work , rapid breathing on exertion , lassitude , loss of f i o o . n appetite , and ther symptoms indigestion Return to work better air , however , soon puts them right .

VENTILATION COND ITIONS IN MINE S . The foregoing discussion of the factors to be considered in ventila tion studies has largely to do with conditions aboveground and in

l . public halls , houses , and other places where peop e congregate With modifications it is applicable to conditions in coal and in other mines . In meetinghouses aboveground the carbon dioxide in excess of the proportion found in atmospheric air is principally derived from exhaled air, and if present , even in proportions as high as per

‘ cent , is usually a sign of stagnant air and poor ventilation . It has been found that this proportion of carbon dioxide usually accompanies very bad ventilation in that the air is stagnant and oppressive , with hi r perhaps gh temperatu e and the odor of perspiring bodies . In coal mines carbon dioxide arises principally from the action of the air on the coal , and to per cent is frequently found in the cool , swiftly moving air of returns , where or more cubic feet of air is passing per minute and the wet -bulb or dry-bulb tempera ° 65 . ture does not exceed F The relative humidity may be high , 1 0 0 ifi almost per cent in many mines , owing to art cial methods of watering to allay coal dust , but where the temperatures are not high

a H ne n O n n i and w s s En s B ue B o a a S . and Os o e 0 . . e a o o a o es o o : Govt . o ld , J . , b r , , V til ti f ct ri rk h p gli h l k,

1 90 2 .

DAM I N M I N ES 1 8 B LACK P . carbon dioxide produced by an adul t as cubic foot per hour: Of il Hence , in cubic feet air, he w l produce per hour a pollution 1 Of i i in amounting to part carbon d ox de parts of air . If the excess Of carbon dioxide were to be kept down to this figure it woul d be necessary to supply cubic feet Of fresh air per hour ; if the permissible excess was to be 2 parts in half this supply would

and . n l suffice , so on The amou t of fresh air allowed by venti ating engineers in this country varies from cubic feet per hour per pers on for school buildings , auditoriums , theaters , factories , etc . , to cubic feet per hour per pers on in surgical and contagious hospitals . In the nongaseous bituminous I nines of Pennsylvania the mini air 1 5 0 i mum quantity of per man is cubic feet per m nute , or cubic feet per hour . In a mine where explosive gas is generated in dangerous quantities the minimum is cubic feet per hour per man . These quantities exceed the quantity stipulated in the in ventilation of large public halls . Consequently the moving air ways Of such mines the air is fresh and wholesome . The temperature i l is is seldom h gh , and usually bad venti ation ex ts only at some working faces where the air does not find ready access . There h as been considerable discussion regarding a scheme pro posed in England to lower the oxygen content of the air in mines to a point (about 1 7 per cent) where the risk from explosion Of m ix i tures of methane and air is reduced . Most m ning men are Opposed ’ to such procedur e on physiological grounds . The author s experience h as indicated that the oxygen content has to be reduced below this li figure to lessen appreciably the habi ty of gas explosions . (See pages 2 4 Some investigators have argued that dis astrous co al—dust explo sions Of recent years can be attributed largely to the better ventil a tion Of mines at present as compared with the ventilation found n years ago . To make such a comparison just i volves the considera tion Of too many factors to warrant discussion here . There is truth a as in the statement , at le st regards mixtures of methane and air, to the extent that greater violence is exerted by an explosive mixture Of if the latter has a high initial velocity its own . The authors have seen this demonstrated many th es in an explosion gallery Of “ their own construction . But an unbiased consideration of evidence accumulated through long experience must lead one to accept the necessity Of plenty of fresh air . Whether for a m iner Working un der a a in“ ground, man at a he lth resort, or an assemblage a large public e i i . build ng , all the fresh air that can r asonably be obta ned is needed

0 s be u s e a e . The n a ve o es of th e a e es r D e a to s a e oweve o a t il p bli h d l t r high i iti l l citi g ll ry t t , h r, pr b bly wn in es w e e an ex os ve m x u e of me ane and air m ex s almost unkno min h r pl i i t r th ight i t . N A L AC TI O N OF O" YGEN O C O . 1 9

A CTION OF O" Y GEN ON C OA L .

Of b Many investigations have been made into the mode a sorp tion i Of oxygen by coal, which is of much practical importance , for th s reaction is mainly responsible for the depletion Of oxygen and in de ri crease Of carbon dioxide in the atmosphere Of a coal mine . The t mental effect is that in some parts Of mines atmospherbes are produced so low in oxygen that they will not support the com ustion of lights Off or that they impair the health of the miners . By sealing affected il z i areas , oxygen absorption by coal can be ut i ed to extingu sh mine

fir es , to prevent spontaneous combustion , or to produce an atmosphere Of air so low in oxygen that explosions methane and , or coal dust and

a ir . , can not occur The exact manner in which coal absorbs oxygen is not clearly A in understood . solid substance can hold gases actually dissolved Of its interior . With coal , the absorption oxygen is complicated by in is o the fact that, addition to this physical action , there als a very Of O is complex chemical action . Part the xygen converted into water, in r i part to carbon dioxide , and part is eta ned as combined oxygen , Of producing compounds richer in oxygen than the coal itself . Part o the carbon dioxide is retained by the c al, for coal at ordinary tem peratures has an enormous capacity for holding carbon dioxide . Many investigations have been made into the absorption and liber bibli b is i ation of gases y coal, as ndicated by the following selected o graphy

o b h o or tio and libe ation ases coal biblio a n abs n . S elected gr p y p r f g y

i ti n t th e ch emist Of coal with s ecial e e enc e t W . A cont u o o o AN D ERS ON . , C r b ry , p r f r l — w vol . 2 1 897 . 2 . in hil . Soc . G as o 9 7 96 the oals Ofthe l de Bas . c C y P g , , , pp al h m l 1 in l s in us t . e . News vo . 68 1 893 . 8 B ED S ON . . The ases c o e co 7 . , P P g d d C , , , p l h ns l an l ati n M E u s sur es c a o o uits esu t t de eur ox o . BOU D OU ARD . O. t e , d rb , pr d r yd — 4 1 8 . ll him . France ser. t . 5 90 9 . 3 77 3 0 Bu . Soc . c , , , , pp E I n x l si m ine as es and usts ith s ial H M RL N R . . Notes o e o e w ec e e C A B A , T p v g d , p r f r i h M n n ah Da an Na mi al min B l l ns in t e d o co es ul . 2 ence to the ex os o o o . 6 p g , rr , ,

in f l . Bull . Bureau Of Mines . 3 2 e t O . S . Geo . Su , p (r pr U rv - i n f s ans . I nst . Min . En . l 4 1 1 1 4 E The etect o O o e . vo . 6 9 3 R R OHN . b H G A , J d g fir Tr g , , ,

3 70 . p . M l m i n f al an i th m a n HILL A . . Th e s o o ust o O co d ts e l L MPLO GH F . E. E . a d w c A U , , , b r

l ans . n . Min En l . 45 1 1 3 2 . a ue . I st . vo 9 . 6 9 v Tr g , , , p F f llin is tat l i al W . and WHEELER . . Year oo O I o S e eo o c Su e RR S . W b G PA , , , k g rv y . l B ll . 1 . 1 8 . ll tat e . urv I . S e G o S ey u 8, 90 7 , p 6 ’ FF i n r s h ill a P ri n TA A N EL . De l alterat o des oussie e de ou e ex osé es air O i al , J p p . g

m . l 1 1 2 2 omm uni cations 8th I nt . on . A l . h e vo . 0 1 9 . 77 C , C g pp C , , , p F I n n in f al a ti la l in i HREL LL R C H RD . The s o ta eous h eat o co cu u sh T A , A p g ,p r r y d r g p m n m n . h . d . l 1 I . e t . ou Soc . e vo 3 8 90 9 . 75 9 . J r C , , , p E F in l in al an RO RI D G . Gases c ose co d ertain al h m G . c co usts . our . Soc . e . T B , d d J C n l 2 I d . vo . 5 1 . 1 1 2 , , 90 6 , p 9 . D M P I N M I N ES 2 0 B LAC K A .

Recent investigations into the action of air on coal are those of “ Winmill and Graham . b ‘ Winm ill determined that under his conditions of experim ent ff Of there was little di erence between the rates oxidation by air , Of except for mother coal and slate, between various parts of a seam

Of coal that he sampled . Hard coal , soft coal, cannel coal , j acks ,

'

. u tha t the a u shale , and mother of coal were tried He also fo nd mo nt Of oxygen absorbed was roughly proportional to the amount Of car bon aceou s matter present in each substance . One hundred and

- 1 6 . fifty grams Of " OO mesh coal absorbed 9 to 83 0 c . c of oxygen at ° ll a temperature of 3 0 C . Winmi states that there are two factors Of — a fir in the oxidation coal rapid st reaction , which is soon over, Of a nd a slow reaction , responsible for the maj or part the oxygen absorption . He found , as have other investigators , that oxidation f O coal , so rapid that the coal heats up , can take place in the absence l of pyrites , only a smal amount of carbon dioxide being produced . ° 2 From the hard coal at 3 0 C . less than 0 c . c . of carbon dioxide was f 2 f formed during the absorption O 0 c . c . of oxygen . A reduction O the proportion of oxygen to per cent (not of the quantity Of air) did not slow up the reaction very perceptibly . With 1 0 0 -mesh dust the rate Of absorption was 72 per cent Of that - n Of m with 2 0 0 mesh dus t . Increasi g the temperature the experi ent ° ° l from 4 0 to 6 0 C . practical y doubled the rate of absorption . In an other communication Winm ill c gives the results Of some ex peri f f ments on the rate O absorption O carbon dioxide by coal . The ° f temperature of the experiment was 3 0 C . The proportion O carbon

1 0 0 . O. dioxide absorbed by grams of coal varied from c , with

n a 4 72 . . per ce t of carbon dioxide in the tmosphere , up to c O , n with an atmosphere co taining 1 0 0 per cent of carbon dioxide .

I N F L UEN CE OF M OI S TUR E ON R A TE OF A B S OR PTI ON OF

OXYG E N B Y C OA L .

“ F ayol maintains that there is little evidence in support Of the a view that mois ture accelerates the fir ing of coal he ps . Richters “ concludes that more oxygen is absorbed by dry than by moist coal . Mahler f found that coal in the presence Of oxygen under pres sure absorbed a considerably larger quantity when moist than when dry .

0 I Th so on ofOx en oa Tra m . e a : ns I i E 1 M n vol F . 1 9 5 G a a . . ns . 9 b . n 5 e . 3 5 . r h , J , b rpti yg by c l t g , . , , , p b — T F Th e a sor on o f Ox en oa : T a I i E M n . ol 46 1 91 3 1 4 Winmill . . ns . ns . n v , , b pti yg by c l r t g . , , pp .

5 63 . 5 68.

c l . 4 F 1 1 5 . 1 4 O . . vo 8 eb. 9 5 . inmi T F W ll , . . , p cit , , , , p d Th s on aneou s ea n o f coal a a m o So C em T e a R a e u ur n s en : ur c. . hr lf ll , ich rd , p t h ti g , p rtic l rly d i g hip t J . h

l 28 63 . I n . 1 90 9 vo . . 7 d , , , p e T r e a R a O . . . 759 . h lf ll , ich rd , p cit p m n n h e oxi a on of oa C ol G 0 f M a l e M . P . Ex e e s o t : . ua d 1 91 3 vol . 1 6 . 891 . h r , p ri t d ti c l l r , , , p ' N W D A CTI ON OF AI E O OO . 2 1

° Graham determined that ( 1 ) at temperatures below 5 0 C . coal dust when moist absorbs oxygen at a rate approxim ately half as gr eat again as when dry ; (2 ) that coal dust heated for some hours ° at a temperature Of 1 0 0 C . in a vacuum during subsequent oxida tion absorbs oxygen at the same rate as when not previously heated ; ba (3 ) that the absorption Of oxygen by coal is independent of cte rial activity . b Porter and Ovitz found that 1 0 kilograms Of coal (22 pounds) in a bottle absorbed during the fir st day after mining nearly half the oxygen from 1 0 liters of a ir and gave Off little more than one- tenth as much carbon dioxide as wou ld have been formed if all the oxygen had combined with carbon to produce carbon dioxide . Four coals that 7 9 1 0 1 7 Porter and Ovitz tested in bottles absorbed in , , , and months Of and volumes oxygen , as compared with a ccum u the volumes Of the coals . From time to time the gas that lated in each bottle was drawn Off in order to relieve the pressure and permit the inflow of oxygen . Porter and Ralston 0 found that with the same coal the rate of f oxidation increased from c . c . O oxygen absorbed per gram Of ° °

2 C . f dr 40 . . . 0 0 O y coal at C to c c absorbed at , the duration each test being 60 minutes . They found that the oxygen content air 1 5 Of of the must be reduced below per cent , or to a pressure about efl ect Of 1 0 0 mm . when pure oxygen is used , before the on the rate Of 1 0 oxidation becomes serious , and that the presence as much as per cent of carbon dioxide in the atmosphere has no retarding in ° fluence on the rate Of oxidation at 20 0 C . c Winm ill , it will be remembered , found that if the per entage of oxygen in air be reduced to the reaction did not slow per ibl Of ce t p y , but his results are not in harmony with those Porter and

Ralston . It is certain , of course , that the rate of oxidation must eventually fall decidedly when the oxygen content Of the air be comes low, and must be zero when the oxygen content of the atmos phere is zero .

A B S OR PTI ON OF OXYG EN A N D PR OD UCTI ON OF CA R B ON D A I D I OXI E F R OM TM OS PHER C A I R B Y WOOD .

M n m in i es eci any metal mi es are heavily ti bered and some m nes , p in ally dead ends where the air is stagnant , the wood is moist , and m Of much ti ber is present , the carbon dioxide content the air is in creased and the oxygen content is decreased .

0 Th e a so on o f Ox en oa T ans I ns in E a am J I . M : t . . . vol . 59 F e . 1 91 5 G . . b ng , . 3 5 . br h , , b rpti yg by c l r , , , p P H C an O z F Th e es a e of s o o T P o e . . d v . K . a m a : e a e 2 B ureau of M nes 1 91 1 rt r , , it , , c p g fr c l ch . p r , i , , 6—7 pp . . c Po e H . C . and Ra s on O . C . st u of th e ox a on of oa : Te Pa e 65 B ureau Of M nes rt r , , l t , A dy id ti c l ch . p r , i ,

1 91 4 . 1 3 . , p D M I N M I N E 2 2 B LA C K A P S .

Some results by the authors on the action Of air on wood are gi ven Of in Table 3 following . Dried and seasoned pieces wood plank were sawed or shaved to produce sawdust or shavings. The material was placed in bottles having a capacity Of hters and the bottles were securely closed . Through each bottle stopper was placed a glass tube provided with a stopcock to permit drawing out samples of air for analysis .

Resu lts of experimen ts to determine ej ect of wood in changing composition of atmos

pheri c air.

Firs t Second Third Si xth analysis analys is analysis analysis of re oi t e oi re ofre ‘ s1 dua1 s 1 dual s i ne s1 dual idnel idn K n ofw oo . e t. s s el i d d W igh . . d_ i 0 air air air air air a , , , , , ir, 2 1 A u 21 S D une 7 u 1 5 u 3 . e . 1 6 ec . 1 2 J , J ly , J ly , g , pt , ,

1 91 3 . 1 91 3 . 1 91 3 . 1 91 3 . 1 91 3 .

P ent. n P en . P er en P n ms P er en . er P er e t. er t t. er e t. P n G a . t er e r c c c c c c t.

0 0 0 g . 6 6 5 2

. 0

. 0 . 1 5

. 20 . 20

. 3

. 2 . 2 4

a af er th es s a and u o es a e Water was added to each bottle 1 5 days t et ts were t rted j s t pri r to th e an lys s .

D I S C U S S I ON O F RES ULTS .

Th e J 6 1 9 1 3 fi experiments were started on une , , and the rst anal NO yses of the residual air were made on June 27 1 9 1 3 . appreciable change in the oxygen or carbon dioxide content of the residual air f over the composition O ordinary atmospheric air was noticed . The ul O J 1 5 1 9 1 3 3 9 same statement held true of res ts btained on uly , or r days afte the experiments were started . Water was then added to each bottle in suffi cient quantity to perceptibly moisten the sawdust n 1 6 and shavi gs , and analyses were again made . After days from Of the time the wood had been moistened , analyses were made the residual air , and a marked increase in carbon dioxide and a marked in decrease in oxygen were found . These changes continued the i l sawdust samples unt l the oxygen had practical y all disappeared . The rate of absorption of the oxygen by the fine cypress shavings was w in slower , probably o ing to the fact that the cypress wood was not fin e as a state of division as the other woods tried . An interesting featur e Of the results was that the carbon dioxide was only S lightly less than the molecul ar equivalent Of the oxygen

consumed . This result differs from that obtained when oxygen is

absorbed by coal at ordinary temperatures . The amount Of carbon dioxide produced by co al is invariably less than the molecular equiv

lent f . t a O the consumed oxygen In fac , the oxygen may entirely or N N N D RAI SI N G ARB ON DI O" I DE ON EN LOW ERI G O" YGE A C C T T. 2 3

l r e a most enti ely disappear , and there may be present in the r sidual air only 2 or 3 per cent Of carbon dioxide . Bacterial action appar - ently does not enter into the phenomenon , whereas as regards the a reaction between wood and oxygen , bacteri l action is probably almost

Wholly responsible .

EF F E C T OF L OWERI N G OXYG EN A N D R A I S I N G C A RB ON D I OXI D E - C ON TE N T ON EXP LOS I B I LI TY OF M E THA N E A I R MI XTUR E S .

l r ul the In coa mines , especially if the air is not in apid circ ation , Of i a composition the atmosphere may change quickly . The pr ncip l changes that affect the explosibility of mine atmospheres are those caused by the absorption Of oxygen by the coal and the oxidation of f fa coal to carbon dioxide . Both O these changes if carried r enough can resul t in so lowering the oxygen content or raising the carbon dioxide content that an explosion can no t take place even if an ex Of of plosive proportion methane is present . Therefore , knowledge Of Of di the propagation flame in limit mixtures methane , carbon oxide , oxygen , and nitrogen is important . Haldane was the first to publish results Of experiments bearing i on this point . The composition of those m xtures containing the smallest percentages of oxygen that he found woul d completely in l i . n flame follows Haldane presented his resu ts terms of black damp , ha e fire . ll w ul V damp , and air In the fo o ing table his res ts been ul Of recalc ated to show the percentages carbon dioxide , oxygen, me : thane , and nitrogen

I n am able mixtu m t fl res con aining sm all percentages of oxygen .

M u e N ixt r o .

P . ct. P . ct. P . ct. P . ct.

4. 21 1 1 . 90 7. 46 76. 43

3 . 5 8 1 3 . 23 6 . 85 76 . 3 4

3 . 41 1 3 . 63 6 . 46 76 . 5 0

’ Haldane s experiments were made with gas Obtained from a coal i S Of m ne , which was passed into a cylinder , the ize a lamp chimney,

. ff from above Ignition was e ected by a small flame from below . Others wbho have worked on this phase Of the subj ect have been , Har er —Rin u et c “ g , Leprince g , and Burgess and Wheeler , but the

a Ha ane . S . I nves a ons on th e om os on o u en e and o e t es of a am : T ans ld , J , tig ti c p iti , cc rr c , pr p r i bl ck d p r . Ins in n — — . . E . vol . 8 1 894 95 . 5 49 5 67. t M g , , , pp bH hn Th a e o e even on of ex os ons in m nes T I Min E 1 1 2 . 1 3 2 : ans . ns . . n . vol . 43 9 rg r , J , pr ti pl i i r t g , , , pp ,

1 3 6 .

c - Le n e Rin uet F . The infl bi mma il t of fir a e am and o e ases : C o . G ua d vol . 1 0 8 Au . pri c g , , y d p th r g ll r , , g

1 4 1 91 4 . 3 76 . , , p d B u ess M . and ee er R . V . Th e o a a on of flame in m t m x ures of me ane ox en rg , J Wh l , , pr p g ti li i i t th , yg , — and n o en: our . C em Soc . vo s 1 5 . . 0 and 1 0 6 Novem e 1 91 4 . 25 96 260 5 . itr g J h l , b r , , pp K D M P I N M I N ES 24 B LAC A . most exhaustive experiments having to do with the explosibility of - i Of Of re methane air m xtures , in which part the oxygen the air was o r r placed by nitrogen carbon dioxide or both , have been perfo med “ by Clement . ’ In Clement s first experim ents the gases a t atmospheric pre ssure were contained in a Hempel explosion pipette over mercury . The source of ignition, a spark from an induction coil, was applied near the top of the pipette . un mi infla m abili re n Clement fo d that the li ts of m ty we arrowed as the oxygen was diminis hed until with 1 4 per cent Of oxygen the low Of e limit was per cent methane and the high lim it per c nt . h The inert gas present was nitrogen . W en the oxygen was kept con stant at 2 0 per cent and part Of the nitrogen replaced by 1 0 per cent of carbon dioxide the low limit was raised from per cent Of methane i 20 to per cent . When the oxygen was aga n constant at per cent it required the replacement of part Of the nitrogen by 62 per ce nt of carbon dioxide to rais e the low limit to per cent Of methane . Clement found that even when the oxygen was reduced to 1 7 per cent infla abili Of - there was no change in the mm ty methane air mixtures from the per cent hmit Observed with 2 0 per cent Of oxygen . Another set Of resul ts was Obtained by Clement with a steel tube i closed at both ends to hold the mixtures . This tube was prov ded wi s — i in n th stopcock , an electric arc gniter, a mix g device , a wi dow for O i araffin - bserving the flame, and an opening covered w th a p paper diaphr agm through which the pressure was released . The igniter was designed so that an arc could be maintained momentarily or for an d are on o 220 -V Olt d r y esired time . The was c nected t a , i ect e t i wi i in to i ur Of curr n circu t, th suitable res stances series g ve a c rent

Of . amperes , and was placed at the center the vessel With this device the low lim it Of methane with 1 9 per cent of n oxygen was per cent, or per cent lower than that fou d by the 1 h it firs t method . With 7 per cent of oxygen the low m was raised 1 3 Of to per cent, but even with per cent oxygen the mixture was explosive with a content of per cent as the low limit and per i r cbent as the h gh hm it . This second series of expe iments again rought out the fact bthat a large proportion Of carbon dioxide was necessary to apprecia ly affect the limits . Clement concluded that the action Of carbon dioxide in reducing — b the explosibility of methane air mixtures can be accounted for y the i h s Of his n di h g pecific heat t gas . He fou d that carbon oxide was r ff mo e e ective than nitrogen in reducing explosibility . The reader shoul d note that atmospheres without enough oxygen (about 1 7 per cent) to support an Oil-fed flame may be explosive if

a C emen K Th n n n ma e aseous mix u es : Te . Pa e 43 B u eau . . e uen e of e t ases o nflam l t , J , i fl c i r g i bl g t r ch p r , r M o f ines 1 91 3 24 . , , pp

B LA K D M I N M I N E 2 6 C A P S .

In most metal mines , lights and the breathing of men and of ani mals are more important in removing oxygen from and adding car bon dioxide to the mine air, because less oxygen is removed and less carbon dioxide is added in other ways .

L I N G OF M I N E A I R B Y D E A OF I M B ER F OU C Y T . hi In all mines in w ch timber is used , some oxygen is taken from the air and some carbon dioxide is added to it by the decay Of the timber . This source of black damp is much more important in many metal mines than in most coal mines because of the much larger l quantity of timber used , especia ly in heavy ground . Timber decays Of Of hi through the action various low forms plant life , c efly fungi , some of which take oxygen from the mine air, and practically all

Of which give Off carbon dioxide .

I S PE CI F I C G RA V I TY A N D COM POS TI ON OF B LA CK D A M P .

The specific gravity of black damp varies considerably . Wh en h hter methane is present the combined gases may be g than air . Great caution should be exercised when any accumulation of black h hter air damp g than is found , especially in mines worked with h hts e naked g , as the lesser density is probably due to the presenc of methane . A sample Of the following composition w as collected by the authors from a cavity in a room Of a coal mine

Results o anal sis o sam le o mine air o mu ch less densit than atm os he ic air f y f p f f y p r .

Of fi Owing to the large amount methane present , the speci c grav ity (air = 1 ) Of this sample was only The analysis Of another sample showed an accumulation Of methane and a deficiency Of oxygen in an inclosed section of an anthracite mine that had been sealed for six days because Of a fire in an fire f adjoining section . The did not af ect the particul ar area from Obtained bec s hi au e Of w ch the sample was r a heavy intervening roof fall ; consequently the sample represented the gases trapped in fire f a stagnant section unaffected by . The results O analysis follow :

Re ts o anal ses o sam les o as in an inclosed are o n su l f y f p f g a f an a thracite mine .

1 0 0 . 0 N K M SPECI FI C GRAVI TY A N D C OM POSI TI O OF B LAC DA P . 2 7

The specific gravity of this mixture (air = 1 ) was only owing f to the large proportion O methane . Mixtures containing a large amount of carbon dioxide are Often

- found on the floor and in low lying workings . It happens occasion

-ally that the gas is in a heavy stratum with lighter air above , and these strata are at times so sharply defined that a lighted candle is extinguished at once by lowering it only 1 inch below a certain

level . Equally distinct stratification of gases may be encountered in i metal mines . A mixture containing more carbon diox de, and

being consequently heavier than normal air may lie near the floor ,

. or a mixture containing less oxygen and more nitrogen , and being consequently lighter than norm al air may accumulate near the roof E r . i or in a raise ither the heav er or the lighter mixtu e , dangerous fi to the miner , may be so well strati ed that a few inches will make

the difference between breathable air and suffocating gases . n Before starting some work near the floor , a mi er may hang his s lamp well up in the roof , where by burning it indicate that the air near it is breathable ; while the air near the floor may be so bad that

it would extinguish the lamp immediately . However , except in air

' fir e fire Of directly over a area or close to a , a large amount carbon

dioxide (over 5 per cent) is unusual in a coal mine . The small pro portion Oi carbon dioxide normally in mine air is indicated by the E many analyses of samples presented in this report . xceptions are

5 866 5 86 7 5 785 5 786 . samples , , , and (see p in which the carbon dioxide percentages were and and the specific gravities and The samples were r fi collected from sealed mines in which the e were or had been res . The authors ’ experience as a result of analyzing gas samples col lected from many mines has indicated that if the carbon dioxide resul ts from the action of the oxygen of the air on the coal (including

perhaps a small amount released from the pores of the coal) , it is not produced in proportions exceeding more than 3 to 5 per cent even

after the air has long been in contact with the coal . Th e following results Of analyses show how small the carbon dioxide content may be in the air Of a mine that has been sealed for i n ne months .

Resu lts o anal ses o as sam les rom a mine area that had bee al d n se e or nine months f y f g p f f .

Sam e N O. pl Total .

0

Per ent. P r nt. e e P er ent. P er nt. c c c ce P er cent.

1 . 50 5 . 29

1 . 20 3 0 5 . 3 7 LA K D M P I N M I N ES 2 8 B C A .

f w ere hin The collectors O the samples breat g apparatus . The nl oxygen had almost entirely disappeared , but o y and per cent of carbon dioxide were present .

EF F E CT ON L I G HTS OF A I R L OW I N OXYG EN A N D HI GH I N D CA RB ON D I OXI E .

All mine air is somewhat deficient in oxygen as compared with fi 2 outside air . This de ciency may amount to to per cent or ll n n more . As the oxygen in air decreases , the i umi ati g power of lights grows less ; the flame of an ordin ary Oil-fed lamp wick becomes n 1 Of extinguished in air containi g about 7 per cent oxygen . Haldane “ determin ed the effect on the hght of a safety lamp fi ll when burned in atmospheres de cient in oxygen . The fo owing him Of n tabul ation prepared by is exceptional i terest .

Resu lts of tes ts to determine diminution of light with diminu tion of oxygen in ur oundi n air s r g .

Proportion of oxygen D egree of in sur light dim i n n roundi g nutio .

air.

O n m i i Of Haldane bserved , in ge eral , that every di nut on per cent in the oxygen content of the surrounding air caused a diminu i Of Of the t on per cent value of the light in pure air . The results Of some experim ents by the authors with atmospheres ul n n that wo d exti guish a flame are show below . Lighted candles and wi acetylene and Wolf lamps were placed in a chamber th air , and when the oxygen content had become so low that the flames were ui a exting shed the residu l air was analyzed .

Resu lts o ex e im ents with atm os he es tha t wou ld extin u ish ame f p r p r g fl .

na s s o f es ua ir A ly i r id l a . S ource o f flam e ext n u s e i g i h d .

P er ent. P er ent. P er en c c c t.

9 1 6 . 24 80 81 O .

6 . 3 0 2 8 . 0 0 3 . 0 0 1 6 . 3 0 80 . 70

a H a ane . S . Th e e e s of e en of ox en on th e , , o f a sa e am : C o . G ua ol 1 ld J ff ct d fici cy yg light f ty l p ll rd . , v . 0 6 ,

Oct. 25 1 91 2 . 83 6 , , p . M A L AI R ON LI GH TS EF FEC T OF AB N OR . 2 9

The carbon dioxide present , which was due to combustion , had no n n appreciable effect in exti guishing the flame , as was show by cer im tain experim ents performed by the authors . In the exper ents varying proportions of carbon dioxide were added to the atmosphere Of in before the flame was introduced . The results analyses made conn ection with the experiments foll ow

o a bon dioxide in extin uishin the ame o Resu lts of experiments to determine efiect f c r g g fl f dl a can e.

C omposi tio n of at m osph ere at end

of ex e men . Experiment p ri t

No .

The results show that the initial presence of a large amount of carbon dioxide had little effect in extinguishing flame . In all of the

' a e robabl ifl laboratory experiments the fl m p y lasted a tr e longer than in n n in it would have actual mi i g practice , because mines a slight gust Of air or a quick movement Of a lamp would easily put out a d n iminishi g flame . For the experiments a certain atmosphere was prepared in a 1 0 b l liter ell jar, and the flame was al owed to burn in it until the oxygen b ul b had een consumed to a point where the flame wo d no longer urn . Incidentally there was formed by the combustion a certain a mount Of d bu no i t carbon iox de , the amounts formed had appreciable effect in extinguis hing the flam Other experiments to determine the amoun t of carbon dioxide i as required to appreciably affect flame extingu shment were made , follows V Of air bd i a arious mixtures and car on iox de were prepared in 1 0 0 - i i large liter gas holder, and these m xtures were slowly passed nto and out of a small bell jar in which was burning a Wolf miner ’s safety lamp . The different atmospheres were kept as near constant 1 7 1 8 1 9 2 0 2 1 to at , , , , and per cent of oxygen as possible , and each Of the mixtures carbon dioxide was added (replacing some nitrogen) until enough carbon dioxide was present to extinguish the flame at

' the particular oxygen percentage used . i S o u i The exper ments how simply the effect n. flame exting shment Of i o f replacing an equ valent amount nitrogen with carbon dioxide . Carbon dioxide shoul d have a greater extinguishing power than nitro Oi gen, because its greater molecular specific heat and its greater ivi Of conduct ty heat . The percentages o f carbon dioxide and of oxygen in the different mixtures that extinguished flame are shown l in the following tabu ation . LA K D M I N M I N E 3 0 B C A P S .

o ca bon dioxide and o ox en in di erent mixtures o the two that extin P ercentages f r f yg fl f uished am g fl e .

O 0 . z. 0 2 0 2 . 2 1 6. 3 5 1 8. 7

1 6. 9 3 0 1 9. 2

1 7. 3 3 5 1 9. 6

1 7. 8 40 2 0 . 3 1 8 3 43 21 0

It will be Observed that a large percentage of carbon dioxide i u s 5 (replacing the nitrogen) was requ red to exting i h the flame , per cent Of carbon dioxide raising the oxygen content of the extingu ish u i Of ing mixt re from to per cent . Th s proportion carbon dioxide in min e air when the oxygen has fallen to 1 6 or 1 7 per cent is unusual . It can be said for all practical purposes that the carbon in dioxide in mine air has no effect in ext guishing the lamp flames .

' Jorris en “ has made experiments and compiled data from various w sources on flame extinguishment , as sho n below

’ Resu lts o Jorrisen s ex e iments with am e-extin uishin a tmos h f p r fl g g p eres .

Proportions in nat Proportions in arti cial extin ural ext ing uish fi uis in a mos e e. in m g h g t ph r g at osphere . n f am K i d o fl e .

P P er ent. P e ent P er ent. e en P e r . rc t. r ent c c c c .

o o o o o o o o o o o" c 2 to

1 5 . 1

The ul Of il res ts experiments of other investigators , as comp ed by Jorrisen l , fo low

Resu l o ex eriments o vario us inves ti a to on am -extin uishin atmos h r ts f p f g rs fl e g g p e es .

f m N atur e o fla e .

Petrol s pirit Gasoline

Methylated spirit

N atural gas

o o o o o o o o o o

C arbo n m onox ide M ethane

a n f m G L n and a e S u vol . 1 3 0 . 6 Jerrisen . P . The ex n o o a es : our . as , , W ti cti fl J ighti g W t r pply, , Apr

1 91 5 . 27. , p W -O" GEN AI R ON I RES I N M N EFF ECT OF LO Y F I ES . 3 1

Of The agreement most of the results is fairly satisfactory . The m in r experi ents are easy to perform, the pr cipal sou ce of error being u f Of n i C O 0 ins f icient mixing the atmosphere , with its cha g ng " and 2 n nonre re content , in which the flame is burni g , and consequent p n se tative sampling . Jerrisen calls attention to the fact that thereis close similarity b i b etween the extingu shment of a flame , such as a urning candle or gas air n bi jet, in as the oxygen decreases and the lesseni g explosi lity he Of gas mixtures as the oxygen diminishes . If t composition of the n i air surroundi g a burning gas jet is near the extinguishing l mit , the temperature of the flame is almost instantly lowered so much that n the combustible gas supplied can not be ig ited , and the flame goes u out . Similarly with explosive mixt res of gas and air in a globe , i say, when the upper limit of explos on has been exceeded , the oxygen content has become so small that the flame can not extend itself ur ill beyond the so ce of ignition ; that is , the mixture w not explode . This is shown in the following table :

a a howin relation between o en content o u er ex losive limit o mi tu o D t s g xyg f pp p s f x res f ce tain ases and air and ox en content o similar mixtu res tha t will extin uish ame r g yg f g fl .

Proportion Proportion ofoxygen Proportion ofgas in in gas o foxygen upp er mixture at hi ghest explosive that ex explosive i m a i mi . t n ish u l it gu es t .

flame.

N atural gas

a Th e va ues in s o um n w e e e e m ne th e au o s l thi c l r d t r i d by th r .

The comparison fails badly in the case Of carbon monoxide and

acetylene .

EF F E OF A M OS HE RE S L OW I N O G EN ON F I R E S I N E S CT T P XY M I N .

The effect of the oxygen content of mine air on a fire in a mine is important and is as follows : When a burning section Of a mine has been successfully sealed the atmosphere within changes in composi fir un S O tion . It st loses oxygen til the content becomes low , prob 1 E 7 n . ably about per ce t , that flame can not exist ventually the oxygen content becomes so small that the rate of combustion slowly m fire is n decreases , until ulti ately the out and the mi e can be safely

0 S B i min : T P i e F Ga na s as an ai n e es e . a e 1 3 ee u el G A . and Se t M . s a s d n rr l , . , b r , . , ly i fighti g fir ch p r , B f n s 1 1 2 1 B A n O G Ex os l of ases om m ne res u eau o M e 9 6 . u e G . a d e e G . . r i , , pp ; rr ll , . , b rf ll , , pl ibi ity g fr i fi

Te . Pa e 1 3 4 B ureau ofM nes 1 91 6 3 1 . R e G . S . M ne es a e mina s u : Te . Pa e ch p r , i , , pp ; ic , , i fir , pr li ry t dy ch p r

24 B ureau of M nes 1 91 2 . 3 8. , i , , p A K DAM P I N M I N ES 3 2 B L C .

a m Opened . Conclusions as to the approxim te length of ti e a sealed n Of n fir e mi e , or part a mi e , should remain closed after a has been di brought u nder control are hard to reach , because con tions differ l greatly . When the oxygen in an area has been a most or entirely consumed combustion must necessarily stop , and the question then e n s uf is how long the embers , or partly burned coal , can r tai heat rekindhn ficient to permit g on the admission of air . Systematic samplin g and analysis Of the atmosphere in different parts of a sealed S i ul mine will how whether the oxygen d minishes regularly , as it sho d s n fire if toppi gs are tightly built , or whether air is leaking into the area .

RE S L S OF A N A L SE S OF OA L -M I NE A M OS HE RE U T Y C T P S .

In the course Of the investigations reported in this bulletin a large Of n number of analyses mi e atmospheres were made . Methods of “ analysis are given in Bulletin 42 Of the Bureau Of Mines . The fi 1 6 f analyses were classi ed in series from to , and , for convenience O fi n in reference , the original classi cation has been retai ed presenting ul the res ts . The following analysis Of pure outside air is presented for com n Of i - parison with the compositio the m ne air samples analyzed .

A nal sis o u e a ir y f p r .

a bon di xide C C r o ( 0 2)

Oxygen (0 2) it o en N r g (N2 )

1 0 0 . 0 0

Included in the nitrogen percentage are the S O- called rare gases of — b m r the atmosphere argon , ehu , neon , k ypton , and zenon . These

1 Of air gases constitute about per cent of the total constituents and, like nitrogen , are inert . o llow th e di n In the tabulations that f , carbon oxide , oxygen , metha e,

n . Of a a and nitrogen , as fou d by analysis , are given The results n ly S ses have been recalculated to how the air , black damp , and methane t Of present and the percentage composi ion the black damp . The air n Of content is equal to the nitroge equivalent the oxygen , accord ing to the proportions foun d in pure air plus per cent Of carbon di oxide . The black damp is equal to the total nitrogen minus the nitrogen equ ivalent of the oxygen plus the carbon dioxide in the in Of n n mine air excess the amou t per cent) fou d in pure air .

a B u e G . A . and Se e . M . Th e sam n and exam na rr ll, , ib rt, F , pli g i tion o f m ine gases and natural gas

B ul . 42 B u eau of M nes 1 91 3 1 1 6 . l , r i , , pp

L K D M P I N M I N ES 3 4 B AC A .

L —R l TAB E 4 . esu ts of analyses

La o a ana f s am e. or s s S ource o pl b r t y ly i .

R emarks .

e Poin t in min .

P er c e t P r t . P er . P e t. c c r ct. - 1 20 feet fro m face of N O. 8 Air s till ; 1 inch cap on

sa am . eas t entry . fety l p m e an s outh en . . T a e o f e s own 1 7 4 1 3 73 5 1 Face ofN o . 7 try r c th h 20 3 0 5 by safety lamp .

2 C oss u e ween 2 o oms . uan ofair u r c t b t r Q tity , c bic feet per min u te; tem ° erature 61 . . B . p , F W ° 60 F . D . B . e a ve , ; r l ti

umi i 94 er en . h d ty, p c t 2 3 ( a ) 3 ( a ) 4 N

tr at oo 20 ee n . y , r f, f t i by

4 N o . 1 oom 0 11 N o . 1 0 r , en r at oo 1 0 ee y , fl r, f t in g

C a w as ove a sea e . 6 5 Surface crack . r ck r l d 5 area in a drift mine th a t h ad been on fire a sho rt tim e previous ; fire prob ably ou t .

R . . 9 oom 20 feet from a butt . d 7 83 1 0 69 8 80 59 , , 1 0 ee o m oo f t fr fl r . Main intake for boos ter fan Hea in of nor en d g th try , ff o 3 eas t . 6 1 6 eas e ween oom s 5 6 t , b t r

and 5 7. 6 L as t cross cut between

oom s 1 9 and 20 N o . 1 6 r , eas t entry . 6 Main e u n at u as 1 0 0 1 9 3 1 r t r , pc t s h aft . 7 Six e en r at a e 9 90 0 u ee of air er th l ft t y f c , c bic f t p minu te . 7 Re u n air ou se nea u ee of air er t r c r , r c bic f t p

m n u . exh aus t fan . i te 20 ee ns e a e in f t i id br ttic 84 0 1 os n o m { cl i g f r er fire area. 80 feet ins id e brattice i n os n o m e fir a a { cl i g f r r e r e . Ret ur n air course

M a in ret urn cubic feet of air p er ° ininu te; temperat ure 67

F . B . and D . B . rel , W . ; a i ve umi i 1 0 0 t h d ty, cent . 1 0 Point in entry where air 77 66 was consi d erabl dilut ed with return air rom fire area . 1 1 Point in a roo m W here it c ubic feet o f air p er 77 47 o e ou in o a minu e em e a u e h l d thr gh t t ; t p r t r , manwa ° F B ° . 76 . 5 78 y . , W . . , F . D B . e a v . ; r l ti e humid 2 r n 9 e e . ity , p c t 1 1 Manwa i 8 50 u ee o f a r er 95 1 9 . 89 . 66 7 y c bic f t p . minu e em e a u e t ; t p r t r , 74 5 ° B ° . 77. 5 . : . F D Bl a v . r el ti e humid 87 er en ity , p c t .

7 20 0 u ee o f air er . 80 78 4 1 , c bic f t p minu te; j pmperature ° , 74 . 2 B . 5 F . fi D B a i v . e h . r l t e u

mi dit 87 er ent. y, p c ' a Sam e was ol e e at th e to of a o e o e ou mine a ir w as s ui Th e m ne was a pl c l ct d p b r h l thr gh which i s ng . i

i mine a h ad een sea e fo r 3 0 a s e ause o f fire . T e e we e oweve man s mal O enin s in dr ft th t b l d d y b c h r r , h r, y l p g th e ou o ma in m oss e om e e ex us on of air tcr p , k g i p ibl c pl t cl i . - RESU LTS OF ANALYSES OF C OAL M I N E ATM OSPHERES . 3 5

- o coal mine air sam les se ies 1 . f p , r

C alai a o o tion Re a u a e ana s s s ow ng air a am and m e ane . c lc l t d ly i , h i , bl ck d p , th ‘flgfiifiggl g i

B a am l ck d p .

20 3 4 92 0 9

1 4. 3 7 54. 27 25 . 98 84 . 41

1 0 69 40 3 7 40 22 1 6 26 83 74

1 9 3 1 1 2 61 87 3 9

91 0 7

1 . 6 93 1 5 . 73 1 6 . 24

1 8 . 84 71 . 1 5 1 9 . 1 8 80 . 82

1 9 . 9 5 . 1 1 8 7 21 . 3 5 78 . 65

1 9. 73 74 . 5 1 20 . 89 79 . 1 1

b La o a o anal s s C O b r t ry y i , . A M P I N M I N ES B LAC K D .

L —Resu lt o TAB E 4 . s f ana lyses

m e S ource ofsa pl .

Rema s rk .

e Point in min .

P er ct. P er ct. f a n no r e u n . 5 60 0 u eet o air er . 23 1 2 M i th r t r , c bic f p minu e em e a u e t ; t p r t r , B n D B a d . F . W . , . , e a ve um i 1 0 0 r l ti h id ty,

. 1 9

e urn o f 1 4 no en . . u ee of air er 22 R t rth try c bic f t p . m nu e em e a u e i t ; t p r t r , B an D B 67 . W . . d F , . . ; e a ve um i 1 0 0 r l ti h id ty, er n p ce t.

do . . 1 7 Tem 1 ° En at a e e a ure 8 . 75 . 1 . 25 try , f c p r t , F B 2 7 ° B 8 5 . W . . , e a ve umi i 92 r l ti h d ty, r n p e ce t . Seven sou en 25 6 0 0 0 u eet o f air er th th try, , c bic f p m nu e feet from face. i t Main so uth return 3 98 cu bi c feet of air p er minute; tem erature °

78 . 25 F 25 D i . B. e a v hu F . ; r l t e mi i d t 96 er en . , p c t Las tcrosscut o ffifth north 780 cu 1 0 feet of air p er mi m en . nu e e e a u re try t ; t p r t , 81 ° F B . , W . D B e a ve umi . . , r l ti h d 88 er en ity c t . i i Re urn at o om of air 5 cu c ee o f a r er . 78 t b tt , f t p m n ° F W s a . u e 76 50 . . B . h ft i t ; , , ° 77 5 0 D B e a ve F . , . . , r l ti u mi 96 er en h dity , p c t . Sou s e e urn 1 0 0 ee 880 u i ee o f air er th id r t , f t , c b c f t p ° m nu m air a e 78 . 25 W B o s . . . . fr h ft i t ; F , °

78. 75 F D . B e a ve , . , r l ti mi u 98 er en . h dity, p c t Mai n north e u n 1 0 0 u i ee of air er 7 r t r feet c b c f t p . 6 ° m air a m nu e 76 B o s . 75 . . fr h ft . i t ; F W ° D B 78 . . e a ve F , r l ti umi i 99 er en h d ty , p c t . 1 0 0 ee ou e am e e esen e e urn 95 f t tby ighth and pl r pr t d r t .

n n . air om ei hth nin i th right fr , th , en anfi e even t th , l th of"?no a l a e right , rth h u g ; cubic feet ofair per minu ° e 67 . W . B . t ; F , ° . D B . a 68 F . rel tive m u i 95 er en . h id ty, p c t do . e ween e an n n B t ighth d i th Air still . in last break

1 4 do 1 4 Nin le 0 11 no au Sam e of e u n air om th ft , rth h l pl r t r fr a e 1 0 0 ee om en n n en e even g , f t fr i th , t th , l th an e. and we en es off tr c t lfth tri , north haul age; cu bic feet ofair per minute; ° 67 F . W . B . n D , a d . B , e a ve umi i 1 0 0 r l ti h d ty,

1 4 do 78. 47 ° 1 ir leve ose to u Me a m ne 2 5 T 6 . W . B . 0 0 h d l , cl b lk t l i ; F , . ° ea on eas s e . 63 F . D . B . e a ve h d t id , r l ti m d u 95 er en . h i ity, p c t

do . 1 5 . . do 1 5 Seven eve wes at th l l , t , bulkhead . 1 5 do 1 5 U as s a 1 0 ee e ow u ee of air er pc t h ft , f t b l c bic f t p

a m nu e . coll r . i t L S F N L SES OF OAL-M I N E A M OS HERES RESU T O A A Y C T P . 3 7

- — i o coal m ine air sam les se ies 1 ont nue . f p , r C d

C alc l a or o tion Re a u a e ana s s s ow n air a am and m e ane. c lc l t d ly i , h i g , bl ck d p , th gfgfaifidggg f

B a am l ck d p .

0 0 2 .

20 25 1 9 85 80 1 5

20 . 3 0 76 . 66 83 . 42

82. 54

2° 21

20 ° 41 77-0 8

20 . 44 77. 1 9 96 . 40 B LA K D M P I N M I N ES 3 8 C A .

LE 4 —Resu lts o a al se TAB . f n y s

our e f sam e. La ora o ana s s S c o pl b t ry ly i .

R s emark .

P in ne oint mi .

P t er c . P er ct. Per ct.

ee om a e and 20 ee 1 3 . 70 . 0 0 62 20 f tfr f c f t 83 . eas of oom ne 60 0 t r ck , feet wes t ofshaft bottom .

. s 83 . 60 Main return air course cubic feet of air per a 81 0 2 a minu e near shft . t cubic feet of air per ° minute ; 76 W . ° 79 F . D . B . e a ve , r l ti

h umidi t 87 er en . y, p c t d 0 o o o o o o 8 77. 66 o o o o o o o o o o o u ee of air er M8 9 Manwa 20 0 ee in . 77. 6 y, f t by c bic f t p ° m nu e 76 . W . B . i t ; F , ° 79 . D . B . e a ve F i ; r l ti

humid t 87 er en . y , p c t

do d 2 . 0 8 77. 67 f a er N o u a e u u ee o ir 78 . 89 rth ha l g ret rn . c bic f t ° m nu e 66 . 5 . W . i t ; F , ° 5 . e a ve 66 . F r l ti

h umidi t 1 0 0 er en . y , p c t do d Head o fair co urse cubic feet o f air p er minute

M ain e u n n oo o f u ee o f air “ r t r , i by f t c bic f t ° F 93 m n 5 . 5 . air s a u e 7 . h ft . i t ; , W ° D B e a v 77 . 75 . . . e F , ; r l ti

humidit 89 er en . y, p c t

d . 50 78. 88

1 5 ee n en u ee of alir er . 48 8 77 f t i by F try c bic f t 7 . ° minu e 5 5 F VV t ; 7 . ° 77. 75 . D . B e a ve F , . , r l ti um 90 er en h idity p c t .

m ° N o . 1 oo i 9th 77 F . . B . and D . B r , right , W en 4 ee om a e e a ve u mi 1 0 0 er try , f t fr f c r l ti h dity p and 1 8 n es om oo en i ch fr r f . c t .

6 . 3 8 i Ma n e u n 20 0 ee o m u ee o f air er 1 4 1 8 r t r , f t fr c bic f t p 79. ° m ou m nu e 53 5 W B pit th . i t ; F . , . . n D B e a a d . . r l ti ve hu m rlit 1 0 0 er en a y p c t . 1 3 79 . 1 5 ° Re u n air o m 8 and 66 F . . B . and D . B 0 8 1 6 t r fr th , W . 79 . h en e a ve 9t right tries . r l ti humidity 1 0 0

. d o 0 6 . 79 . 23 Re u n air om 8 e u ee o f air er 0 8 9 . 2 t r fr th l ft c bic f t p . 7 2 min ° en . u e 69 . B try t ; F W . . D B and . . relati ve h u midit 1 0 0 er en y p c t .

. 0 7 79 . 1 7 ° Se o n oss u e w n S ill air F W B ° ee t 65 . . 66 43 c d cr c t , b t ; , , 6 . oom n 9th D B e a i v s 1 a d 2 . . . e h u r , right . F r l t m dit 95 er en y, p c t .

o . I . 6 . 62 Re urn o fo ne o ftwo s it s 0 0 1 0 t pl , F 79 . feet from pit m outh .

Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q . 0 2 M ain aul a e wa 20 0 u ee ) er 4 1 4 h g y , c bic . 0 79 . t om o a m inu e ° fee fr p rt l . t ; 55 Ff Wt I; ° 56 . D B e a F . . ; r l tive um i 94 er en h id ty, p c t .

20 . 5 7 0 1 79. 1 7 F N SES F AL—M N TM H R RES U LTS O A A LY O C O I E A OSP E ES . 3 9

a -mine air sam les se ies I — ontinue o co l . f p , r C d

C acu a e om os on Re a u a e ana s s s ow n a ir a am and m e ne l l t d c p iti c lc l t d ly i , h i g , bl ck d p , tha . of black dam p

B a am l ck d p .

C Oz.

93 . 5 1

20 . 61

1 2 . 87 87. 1 3 B A K D M I N M I N ES 4 0 L C A P .

LE 4 — Resu lts o anal TAB . f yses

f m S ource o sa ple.

Rema s rk .

Poin in m n e t i .

Mine sealed when sample 25 - ou se en was o l ec e e aus e of Air c r try . c l t d b c a ev ous in fi pr i m e re.

81 . 24 Fire area in sea led m ine o h in n 45 thr ug hole s to ppi g 77. o f o o O enin utcr p p g . 25

26 Ma n e urn 75 ee o m u ee of air er i r t , f t fr c bic f t p ine m ou . minu e B m th t ; W . . relative

26 do 27 a e of en 3 F c right try, ee wes o fs a f t t h ft .

27 do 28 Mou o f th en 9 th 7 butt try .

do Manw ay 3 0 0 feet sou th cubic fee t of air er wes o i m ou n 2 ° W . m u e 5 . 5 . t pit th i t ; F , °

53 . D B . e a ve F . ; r l ti

humidit 97 er en . y, p c t do d Main e u n 1 0 ee o m u ee of air er r t r , f t fr c bic f t o o m o fair ° s a . m nu e 66 F b tt h ft i t ; . , ° w lativ 67 . D . B . i e e F i ; mid t er n hu 95 e . y, p c t d 8 eas en at ea o f 1 20 0 u ee of a ir er 5 t try h d , c bic f t as oo m hrou o m m in ° u e 75 F . l t r t gh fr t ; , W . 9 eas en 6 ° D B . 7 F . . . e a ve t try , r l ti hu nidit 96 er en y , p c t éo 8 0 7 . 1

a C O er en . 0 C O er en , p c t , p c t .

1 N M I N ES 4 2 B LAC K D AM P I .

LE I ERI E C OM M E N T ON A N ALYS ES OF S A M P S N S S 1 .

The results of analysis of 1 1 1 samples of mine air from 2 9 coal i mines are shown in the preced ng table . The percentage of black damp in the samples varies from to The average per in a centage of carbon dioxide the bl ck damp is per cent, and the average percentage of nitrogen is per cent . The principal factors that probably affect the formation of black d amp in coal mines are ( 1 ) tim e of contact between the air and coal ; r wi (2 ) rate of reaction of a pa ticular coal with oxygen, th subsequent formation of some carbon dioxide ; (3 ) temperature of the coal and

4 . fi the air , and ( ) presence of moisture Of these the two rst are undoubtedly the most im portant ; hence it is to be expected that different percentages of black damp will be found at different places

‘

in . in the same m e In a return airway , where the velocity of the air i in a n current is h gh , and the air has been contact with the co l o ly a m S o Short ti e , mall percentages of black damp are found ; h wever, in i k n air S the same m ne , at a wor i g face , where the travels lowly , or i air in an abandoned part of a m ne , where the is stagnant, the per a i i centages of black d mp may be h gh , conditions clearly ndicated in i by many of the results of analyses the forego ng tables . If all coals upon reaction with air produced carbon dioxide in the o x en same ratio to the y g consumed , then the percentage composition S in of black damp hould be always the same all mines . Laboratory S e experiments how, however , that th re is no such constancy , as some coals produce more carbon dioxide in relation to the oxygen absorbed than do others ; hence black damp formed by the action

of air on different kinds of coal must vary in composition .

A question of interest arises , Should the ratio between the carbon dioxide produced and the oxygen consumed be always the same for each coal ? If one takes a sample of fresh coal and treats different wi u portions of it th oxygen nder the same conditions , practically iden

tical results will be obtained . If, however, one portion is allowed to i if weather a long t me , or more moisture is present in one than in

another, the results are not so concordant . Probably , also , other

factors must be taken into consideration . The analyses given in n S i the precedi g table how a fa r degree of concordance ; that is , samples of black damp from different parts of the same mine do not vary as regards percentage composition of the black damp nearly So n much as do samples from different mi es , although there is lack of strict concordance which shows that even in the s am e mine different

samples differ in composition . - H RE RESU LTS OF AN A LYSES OF COAL M I N E ATM OSP E S . 4 3

M D TY TEM PERATURE A ND HU I I .

Wet and dry bulb temperature readings were taken in 22 of the I 6 i 2 9 mines represented in the fir st series of results . n m nes of the 22 the temperature was higher than it should be under the best — e il n . 1 1 v nt ati g, conditions In mine the wet bulb temperature at hi one place varied from to F . However, t s place was n — in mi 1 3 used only for traveli g. The wet bulb temperature ne ,

i . both at the face and in the mov ng air current , was too high The i proportion of methane was also h gher than it should be , ranging from per cent in the return 1 0 0 feet from the air shaft to I n per cent 2 5 feet from the seventh south entry . other words , the introduction of more fresh air into this min e would not onl y have

it e il . cooled , but would hav d uted the methane present n Mine 1 6 was poorly ventil ated . In the return air course where o ly cubic feet of air was passing (samples 5 0 77 and 5 0 78) the carbon dioxide averaged per cent and the oxygen per cent .

More air would certainl y have been desirable . In mine 1 8 there were high temperatures combined with high i carbon dioxide , low oxygen , and h gh methane content in the air of the manway . 20 w as I n mine , the oxygen content of the air low, the carbon dioxide and methane contents high , and the temperature high .

F A NA L S ES OF S M PLE S I N S ERI ES 2 TO 6 RES U LTS O Y A .

In Table 5 foll owing are presented the results of analyses repre a f i s enting mine ir collected in di ferent mines n this country . The results have been divided into five series following series 1 in the fore in ri 2 3 ll 1 1 going table . The samples se es and were co ected in mines 1 r in 4 in r West Vi ginia . The samples series were collected an anth acite

n n ‘ 5 6 mi e in eastern Pen sylvania , and the samples in series and were i collected in two different m nes In Indiana . In each mine the in air sampler started at the intake , and traveled the direction of the , i S collect ng samples at certain intervals , so as to how the progressive change in the mine air as it traversed the mine and came in contact with more and more coal . The table shows the laboratory number of each s am ple ; the place where the sample was collected ; the composition of the sample as l air received ; the recalcu ated analysis showing the atmospheric , in black damp , and methane the sample ; and the composition of the black damp . Certain observations made in conn ection with the different samples are also given . N M N 44 B LA C K DAM P I I ES .

LE —Resu lts o anal s o TAB 5 . f y es f

S MPLES IN SERI ES 2 ROM A , F

B o e Sam ttl P m of sam in o t pl g . o le N o . N . p

fw Main air course o es t heading . ou se off G een ea n Air c r , r h di g ou se off G een ea n etween Air c r , r h di g , b m roo s 5 and 6 . A ir ou se off G een ea in etween c r , r h d g, b room s 1 4 and 1 5 ou se off G een ea n o os e Air c r , r h di g, pp it room 24 A ir ou se off G een ea in o os e c r , r h d g , pp it room 3 3 A ir ourse off G een ea n o os e c , r h di g, pp it room 42 R e ea n o os e oom 48 itt r h di g , p it r i m R e ea in ri p s e 0 os te oo 1 . itt r h d g , g t id , p r R e ea n oom 5 5 off ef s e at a e itt rh di g , r , t id , f c R e ea n at a e of oom 2 off itt r h di g , f c r , right m R e ea in 3 0 ee o u as air s a . itt rh d g , f tfr pc t h ft

S MPLES I N SERI ES 3 R OM A , F

1 2 left air course ace of air ou se of " en off ten e F c r try , th l ft heading

a e of oom 3 off en ea n . F c r , t th right h di g O pos ite first cross-cut beyond twelfth eft heading B e ween ooms 2 and 3 off we e t r , t lfth l ft heading Room 3 ofi we e ea n , t lfth l ft h di g Room 7 off we e ea n , t lfth l ft h di g B etween first and second cross cuts T n os os u e e en O e s . th l ft try , pp it fifth cr c t Main air course at I ntersection with ninth right heading Ma n air ourse e ween and ou i c , b t third f rth

oss u s e on e ea n . cr c t , b y d ighth right h di g Ma n air ou se 40 ee e on seven i c r , f t b y d th left heading Main air ou se 60 ee in fan c r , f t by

S MPLES I N SERI ES 4 R OM A N N THR C I TE A , F A A

20 0 feet from slope 470 feet from foot of slope 682 ee om oo o fs o e at fac f t fr f t l p , 80 2 feet from foot of $1 0 e 1 527 ee o m oo of s o e , f t fr f t p 2 242 ee om oo ofs o e , f t fr f t l p 3 20 7 ee om oo of s o e , f t fr f t l p 4 3 20 ee om oo o fS o e , f t fr f t l p 4 840 ee om oo o f s o e , f t fr f t l p feet from foo t ofs lope feet from foo t ofsl o pe 6 5 75 ee om oo o fs o e , f t fr f t l p F A - M N E A M O H ER RESU LTS OF A N ALYSES O C O L I T SP ES . 4 5

- mine air sam les se ies 2 to 6 . p , r

E E T I RGI N I A MI N IN W S V A .

C om os ion of sam e as ‘ p it pl received .

P . ct. P . ct. P . ct. P . ct. P . ct.

0 . 0 3 0 . 0 3 20 . 83

. 0 3 0 3 20 80 78 54

0 4 79 0 5

E I N S T R N I A MI N WE VI GI A .

1 9 98

20 24

MIN E I N STERN PENN S N EA YLVA I A . B LA K DA M I N M I N ES 4 6 C P .

LE 5 — Res u l TAB . ts of ana lyses of

S M PLES I N S ERI ES 5 A ,

B ttle 8 1 Po n of a 2 i t s mpling . No 1 3 1 21 50

Main east entry at air co urse M am eas t entry

m0 11 s econ wes en N o . 1 oo r r , d t t y Room 2 o ff se on wes en off , c d t try, eas t e ntry . Roo m 7 seco n wes en off ma n eas , d t try, i t entry Room 9 se on w es en ofi ma n eas , c d t try, i t

en r at a e. t y, f c Second w es t air co u rse at overcas t on first eas t Return at jun ctio n o fmain eas t entry and ma in north entry

S M PLE S I N S ERI ES 6 A ,

oo o fair s a in a e a ir F t h ft , t k Fourth w est air course

ac e o f oo m in e no h en r off F r ighth rt t y , fourth west air course a e ofe no en ofi foru th wes F c ighth rth try, t air co u rs e Roo m 9 s s ou en off i wes , fir t th try, th rd t air corirse Roo m 1 at a e o ff rs so u en off , f c , fi t th try, i w es ai ou e th rd t r c rs . Roo m 2 nea a e at eak ou o ff , r f c br thr gh e no en ofi our wes air ighth rth try, f th course ou wes air o u se e urn s e F rth t c r , r t id

a Sam e ak en at oo o fs a pl t f t h ft. S LTS OF A N A L SES OF OAL - M I N E M OSPH ER S RE U Y C AT E .

- — d mine air sam les series 2 to 6 ontinu e . p , C

N F ROM A MI N E I N I N D I A A .

Re a u a e ana s s to s ow air ac am c lc l t d ly i h , bl k d p , d m an an e th e . C ompos ition ofsample as C ompos ition

a am . received . bl ck d p B ac am l k d p .

P . ct. P . ct. P . ct. P . ct. R ef. P . ct. P . ct. P . ct. P ct.

0 . 0 5 20 . 87 79. 0 8 0 . 0 3 20 . 87 78. 81 2 0 . 27

0 8 20 . 81 0 0 79 . 1 1 0 3 20 . 81 78. 59 0 5 52

0 6 20 . 82 0 0 79. 1 2 0 3 20 . 82 78. 62 0 3 50

0 9 20 . 80 0 1 79 . 1 0 0 3 20 . 80 78. 5 4 0 6 56

1 9 20 . 5 5 0 0 79 . 26 0 3 20 . 5 5 77. 60 1 6 1 . 66

56 1 9. 55 0 1 79 88 0 3 1 9 55 73 82 5 3 6 0 6

0 3 1 9. 59 73 . 97

ROM MI N E I N I N D I N F A A A .

0 3 20 . 3 1 76. 69

0 3 1 9. 89 75 . 1 1 B LA K DA M I N M I N E 4 8 C P S .

MM ENT O N RES UL TS OF SA M PL I N G A N D A N L I C O A YS S .

M PLE ERI E 2 S A S I N S S .

It will be noted that the first s ample of series 2 was collected di i feet from the intake , and the succee ng samples at greater d stances , i until the last one was taken feet from the ntake . In general, the first samples were lower in carbon dioxide content and higher in oxygen content , and consequently contained less black damp , but the the change was not so marked as in samples of other series . The the i composition of black damp was fa rly constant, ranging between per cent and per cent carbon dioxide an d between and

per cent nitrogen . The average composition of the black damp

i . was carbon diox de , per cent ; nitrogen , per cent

M L N E E S A P ES I S RI S 3 .

The first eight of the samples in series 3 were collected in still air at workin g faces . The proportion of carbon dioxide ranged from er to per cent , the oxygen content ranged from to p cent , and the percentage of black damp ranged from to per fi l i . ve cent , a smal but still noticeable ncrease The last samples were collected in the air current and the greater purity of the air is notice of able . The composition the black damp was remarkably constant , rangin g from to per cent carbon dioxide and from to 93 e per cent nitrogen . Th average composition of the black damp was carbon dioxide , per cent ; nitrogen , per cent .

M PLE N ERI E 4 S A S I S S .

The change in the composition of the air as it traversed the mine is much better indicated by the data regarding the samples in series 4 in n than by those for the samples the two precedi g series , because the volume of air traversing the place where each sample was collected did not differ enough to influence markedly the percentage change in l ri the carbon dioxide and oxygen contents . Some irregu a ties due to this cause were , however , noticeable . At the place where sample 62 94 l was col ected , cubic feet of air was passing , whereas at 62 99 the place where sample was collected , cubic feet of air was passing ; this difference in the quantity of air passing made the 62 94 s percentage of black damp in sample appear less , wherea 2 40 in reality the cubic feet of black damp was greater , being cubic feet by as against 1 3 6 cubic feet by for 2 sample 6 99 . S M PLE E E A S I N S RI S 5 .

A noticeable increase in the percentage of black damp is seen in the

a 5 . 63 3 0 63 2 7 3 2 6 63 23 s mples in series Samples , , 6 , and were collected ki in s l hi at wor ng faces ti l air, and consequently were much gher in black

K D M P I N M I N E 5 0 B LAC A S .

hi w as ll low in oxygen per cent) . T s sample co ected in the retur n air where cubic feet of air was passing . The tempera tures were satisfactory .

F LE K G E O F A IR THR OU G H D OORS B R TTI C ES ET C . E FFE C TS O A A , A ,

Necessarily the composition of the air in an entry is infl uenced air greatly by the leakage of through stoppings , doors , brattices , and ns air all al overcas ts . For i tance , the may be practic y norm at a v particul ar place in an entry , not ha ing traveled very far in the

vi e a . mine , and hence not ha ng react d with much co l A short dis di i tance farther , however , a decided change in its carbon ox de and oxygen co ntent might be caused by badly vitiated air leaking i i s thr ough a door . That m ne w ll have the tightest doors , overca ts , hi l unif in etc . , in w ch the air shows a gradua and orm chang e com mi position as it travels through the ne .

M M B L A S M S I N FLA A E G I N I N E .

Although this report deals primarily with the vitiation of co al -min e di i air by changes in the content of carbon ox de and of oxygen , some e m as reference to the pr sence of infla mable g (methane) is required, because coal -mine ventilation is largely governed by the quantity of inflammable gas entering the workings . i m - s s For nstance , the bitu inous mine law of Penn ylvania state that in a nong aseous mine the minim um quantity of air shall be not less 1 5 0 than cubic feet per minute for each person employed , and in a mine wherein explosive gas is being generated in such quantities that ini it can be detected by an approved safety lamp , the m mum quan tity of air sh all be not less than 20 0 cubic feet per minute for each o n person employed therein , and as much more in either case as e or r r more of the inspecto s may deem requisite . Fu ther , under the law us e i hi i mentioned , the of open l ghts is pro bited in any entry , a rway, li n trave ng way , room , or any other worki g place where explosive li o un all a gas is kely to be enc tered, and in such places locked s fety lamps must be used exclusively . al i fl m In other words , the fact that co m nes generate in am able gas in greater or less quantities has necessitated the introduction of . fresh di a air to lute the gas , and this natural gaseous condition of many co l mines has had a great deal to do with keeping the air of coal mines s in good condition . The pre ence of inflammable gas introduces the as s s l in is dang er of dis trou explosion , especial y mines where the air his di not controlled properly , but t dang er , by lea ng to the continu s air ous introduction of immen e volumes of fresh , year after year , has i a undoubtedly been the ch ef element in ssuring good ventilation . GAS I N RO K STRA RI P LE REEK DI R C TA , C P C ST I CT . 5 1

“ i co ns e In general the air in m nes that are termed gaseous , and quently are required to have large volumes of air coursing thr ough them and must be inspected more thoroughl y to keep all parts of the i as i work ngs free of inflammable g , is h gher in oxygen , lower in carbon dio s s xide , lower in temperature , and moves fa ter , and in all way has a higher standard of purity than the air in those mines that are termed nongaseous and hence are not required by law to have as much air s i fresh pa sing through them , and , in wh ch , because they are not as menaced by inflammable g , the ventilation is not regulated as carefully .

OC C URREN C E A N D C OM POS I TI ON OF G A S I N R OC K S TRA TA OF TII E - C RI PPL E C REE K G OL D M I N I N G D I S RI C C OLOR A D O . T T,

i l in i The sen or authors of this paper, whi e Colorado on other off cial i - bus ness , made a trip to the Cripple Creek gold mining district to get more data than is at present available regarding the composition of the gas that issues from the rock strata into the gold mines of the ff district . This gas was said to cause su ocation , and hence to be a f The n ll the menace to li e . data presented herein relate pri cipa y to composition of this gas and its effects on men and on lights . It is estimated that 2 5 to 1 0 0 miners have been killed by the rock gas in the 2 5 years that mining has been vigorously carried on at M Cripple Creek . any men have had narrow escapes from death , ,

vi . some of them ha ng been incapacitated for days In addition , on few certain days men can not enter some of the workings . At a n n n mines fans are used to force outside air i to the mi es , thus improvi g conditions in large measure , but even this plan , as used at Cripple

r i . C eek, is not entirely adequate at all t mes

ORI G I OF THE TRA GA N S TA S .

Lingren and Ransome believed that the gas found in the rocks of the Cripple Creek mining district repres ents the last exhalations o fthe hi extinct Cripple Creek volcano . In support of t s they s tated that in i n little timbering is used the m nes , hence one can not accou t for the decrease of oxygen or in crease of carbon dioxide by oxidation of r e e e is l all i timber . Fu th r, th r on y a sm proportion of pyr te and car

' bonates present in the rocks and ores as compared to that in many

e e . a i other min s entir ly free from gas Moreover, no g s occurs n the wi i n oxidized zone , sho ng that ox datio can not have anything to do i a i with it, and as the gas ncre ses with depth it must be ma nly accu m ul ated in strata at depths below those penetrate d by the deepest mines of this district .

0 m L o o an e os of the C e C ee m nin ist L n en W . and Ranso e . . Ge d o s i gr , , , F , l gy g ld d p it rippl r k i g d rict

U . S . Geo . Surve P o . Pa er 54 1 90 6 . 25 7. l y, r f p , , p M N M I N E 5 2 B LAC K DA P I S .

E URE O N OU T LO OF TRATA E FFE CTS OF B AROM ETRI C PR S S F W S G A S .

The g as is confined in the rock un der such low pressure that vari ar tions in the outside atmospheric pres sur e may mate rially affect the mi e mi e . s r outflow of gas in to the n s Also , at the e n s where fans fo ce i i 6 7 i air in , thereby putt ng the work ngs under about or nches of r ki water pres sure (about inch of mercu y) , the wor ngs are more or les s free from the rock gas which is held back in the pores and in ri es r crevices of the rocks . The variation outside atmosphe c pr su e i Of r is easily more than nch mercu y , and the effect of the barometric pressur e on the outflow of gas is appreciate d by mining men .

M PLE OF G A I N OUR M ET L M IN E C OLLEC TI ON OF S A S S F A S .

l as in M McKinne One of the authors collected samp es of g the ary y ,

Mi s i . ar in Anaconda , dget , and Cre son m nes Data reg d g the samples l e are contained in Table 8 . Genera remarks on some of the min s represented in the tab le are presented as bearing on the data given in the table .

TI N N G A I N MID ET MI N E OB S ERVA O S O S G . S The Midget mine is situated on the wes t lop e of Gold Hill . Th e workings are partly in breccia and partly in the fine-grained gray

The 1 . gneiss comm on to the district . mine has 0 levels From the 2 Shaft to the tenth level is about 90 0 feet . About 0 men work under As e groun d on a leasing system . r gards the men in the levels where e in sampl s of gas were collected , four men were the seventh level , u un fo r men on the eighth , and nobody , on acco t of bad gas condi f . O i tions , on the ninth or tenth In the afternoon the day of sampl ng n the men had to leave the eighth level on accou t of the gas . Gas i n to cond tio s were said be worse than usual at the mine on that day . i Of O The Midget m ne uses a pressure system ventilation . n the surface is a 5 -foot Sturtevant fan driven by a 2 0 -horsepower motor which forces air thr ough an air compartment in the shaft to a point i below the second level , whence the air spreads nto the various levels . d i a ui In the rifts at various d stances from the sh ft are air doors , b lt - ar i as 1 w . s r of inch bo ds and tightened th canv Thus , a small pre su e , 3 4 in u fi or inches water gage , is placed on the mine work gs , s f cient to check in part the outflow of g as from the rocks and enable the an ul wi men to do more work th they co d thout the fan . But when l m a re the outflow of gas is stronger than usua , work en sometimes ri a l d ven from the lower levels , and occ sional y can not reenter for days . N RO K S RA A RI LE REEK DI S RI . GAS I C T T , C PP C T CT 5 3

The Conundrum mine was the firs t in the Cripple Creek district to

hi mi Mi . install this system of ventilation . T s ne adjoins the dget e l M mi o Of the series of sampl s co lected at the idget ne , nly one , 4 w as l e es No . 66 , col cted outside the pr sure area or zone and beyond l s r i 2 0 the door . Cand e bu ned freely nside the door, but feet beyond i i i i s a 1 7 they went out , nd cat ng at th s point le s th n per cent of oxy O the air i suffi gen . Wh en the door was pened rushed through w th cient strength to blow out the lights .

N E G EN ERAL OB S ERVATI ON S RE G ARD I N G G AS EOUS C ON DI TI ON S I N AN AC ON D A MI .

The workings of the Anaconda min e in the town of Anaconda hr il mi is extend t ough Gold H l . The ne worked through an adit An l n u in l . hav g a porta at aconda The prevai i g co ntry rock is breccia , with some irregul ar bodies of latite-phonolite and a few dikes of phonolite and basalt . The Anaconda shaft is reached by means of an adit feet ur fif and long . The fo th and th lower levels are at times much i in troubled by rock gas . The progressive v tiation of the air the fourth drift of the four th level is shown by the data presented in

Table 6 regarding the first s ix samples from the Anaconda mine . in 69 1 3 0 0 t af n In tak g sample , feet nor h of the sh t , which contai ed

per cent of oxygen and per cent of carbon dioxide , the sampler advanced with an acetylene lamp held near his mouth , until 1 2 1 3 r the lamp went out (about or per cent oxygen) , then eached l down and col ected the sample near the floor . The dangerous fi strati cation of the gas is well shown by these analyses . At the ’ t height of a man s mouth the air was breathable , but a the floor a man woul d coll apse quickly because of the small amount of oxygen il fi n per cent) there . Sim ar strati cation is show by sam ples i taken at other po nts . It was noticed on another occasion that a lighted candle would l f c burn fairly we l at one point in a dri t , but be ome extinguished r l fu ther a ong , although great care was taken that it shoul d not i be extinguished by a sudden movement or j erk . At a po nt still u in f u . U f rther the dri t it wo ld stay lighted sually, though, the nearer one approached the breast of a drift containing much rock gas the worse the air became .

O S ER TI ON S 'ON GA S I N C RE S S ON MI N E B VA .

The Cresson mine is on Raven Hill a bout two and one-h al f miles o M i i fr m the idget m ne and two miles from the Anaconda m ne . It

1 3 . un is has levels The prevailing co try rock andesite breccia . A wooden door made as tight as possible is placed in e a ch dr ift beyond the workings and a compress ed-air pipe is run through a B L K D M P I N M I N ES 5 4 AC A .

al hole in the door and is se ed around as tightly as possible . A valve ni co placed inside the door provides for tur ng on the mpressed air .

When the air is turned on the rock gas is kept back . The effective ness of this plan is shown by the anal ys es of samples collected inside and beyond one of these doors . In collecting sample 760 the collector advanced 1 0 feet beyond air where the was comparatively good , holding his breath , then i qu ckly snapped the sealed and evacuated glass sample bottle , min m fi f i whereupon the e gas im ediately lled the bottle , a ter wh ch E . for he quickly came out ven so he had a narrow escape , his his i i kn ees became weak and m nd slightly hazy, ow ng no doubt to i As inadvertently breathing a l ttle of the atmosphere . soon as he 1 all came to better air 0 feet away he felt right . Sample 760 showed the effect of the compressed air in holding ’ back the rock gas . At the height of a man s head j ust at the door 1 the oxygen content of the atmosphere was per cent , whereas 0 l feet beyond the door the oxygen content was on y per cent . This sample more closely approximated the pure rock gas than any other collected . So -called blowers of gas are difficult to find in the Cripple Creek Th e Of u i mines . escape gas from the rocks usually is n form from thousands of small pores rather than from large outbursts at ' one l - particul ar place . If one calcu ates the air free composition of this sample (No . by eliminating the nitrogen and oxygen accord n ing to the proportions fou d in atmospheric air , the composition i becomes per cent carbon diox de and per cent nitrogen . fi r S if u These gu es how the composition of the pure rock gas , one ass mes that the air in the sample as collected was due to dilution of the rock gas by the min e air .

Apropos of the occasional small outbursts of gas from the rocks , it is interesting to mention at this poin t an incident related by the i r superintendent of the Midget m ne . In the cou se of his duties in the min e he was leaning again st the wall of a drift with his face close n to the rock , talki g to another man . Suddenly he felt dizzy and his breathless and knees became weak . Although not knowing the cause of his distress he changed his position and soon felt better . Then it occurred to him that possibly a small feeder of gas was fin ding its exit close to where he had been standing ; so he put his n a carbide lamp up agai st the rock at th t place . It was immediately extinguished , showing that his assumption had been correct .

TA B U LA I’ ‘ ED D T A A .

6 Table , presenting detailed data regarding the s amples taken u i in the fo r m nes under consideration , follows . V V AS I N RO K S TR T RI P LE C REEK DI S TRI . G C A A , C P CT J 0

m 2 v $ m g a 8 5 o 8 s o 9 8 m 5 b n w w s a q o S a a 3 : . n s a o a t » g 3 o . m e s a fl 8 E fi 2 v 3 o £ o a o bo 3 5 n w 2 n e 9 o m a 5 0 b 3 “ 6 a n 8 a s 3 e 8 o 3 o c m3 N 5 d 3 a 9 a 6 o o m 8 w 9 a e a A n 3 n — “ w 5 o 3 3 e i w o 3 Qg e 8 g 8 c n “ 0 QB 8 £ o o ? ? 8 8 8 2 t 3 S bw S 3 s S2 e o 5 H 6 o 3 : 5 8 8 o &n E 8 8 e S 3 3 m 8 v “ 0 a 8 o q oo 3 S s 3 8 o g o 8 z z

c 0

a 2

o a m m m m 2 3. e m

o o o a a w n 9. w m n

n “. m w m m w o 3 c m o w m w » w

o o a

n 3. n. m.

m 3 o 8 3.

m m. m m. o o 8 w

S a E s S 2 s s s 5 w c 8 E S 8 a m E S$ 5 g 8 o 5 S S w n e a E5 s 5 E s e 3 s E3 a S m c fl m - o S s S m a . s 8 w E o ” g o S w S S a s 4 a S o a s s 9 n ” E Ea s S s s w 3 5 : ? m S S p . 2 a o o Ba S u n n 5 o w o 5 3 fig e 5 bb° e s s 5 2 8 m m D M I N M I N ES 5 6 B LA C K A P .

0 .

S S S S m. e 8 E SE S A N E S S B . 5 £ S E S . 5 u E 5 E o 5 6 S o S S u 5 S £ . E SS L E S 5 o 5 E o o 8 E E c 8 c S S S . S S S 5 S 8 L S e 9 o S a 2 Eo . 8 Em E6 Ea u m p E o S 8 S S L 5 S e S a 9 o am a o S E s : 8: s 5 s : u O h a h h m

e 1 6 7 0 4 ml 0 9 6 3 5 9 6 9 7 3 a fl 9 S

B A K D M I N M I N E 5 8 L C A P S .

’ PEC I L A I R S M PLES ROM M R M K I N N EY M I N E S A A F A Y .

The Mary McKinney mine is S ituated on the south side of Squaw n firs in O . Gulch , pposite the town of A aconda The t ore was shipped inl in a 1 93 i . 8 . The work ngs are ma y brecci and phonolite Data on the air samples coll ected in this min e by one of the authors is shown in Table 8 . At the instance of the authors mine-air samples were collected by i i 2 2 A . G . Suydam , a m n ng engineer of Cripple Creek , for days , almost McKinne n in 1 2 il in . da y, the Mary y mi e , the No north drift , on the

- i 0 . s am 80 foot level, about feet from the shaft The po nt of “ ” plin g was close to a fissur e in the rock from which a feeder of i rock gas intermittently ssued . Table 7 following S hows the num ber of samples collected at this i and n . poi t by Mr Suydam , date of sampl ng , results of analyses , the . direction of the wind and the barometric pressure ou the date the samples were collected

L — D ata e a din as sam les coll cted nea eede in Ma McKinne mine TAB E 7 r g r g g p e r f r ry y .

Analys is . B u “ C “ m m rsa ease .

1 91 5 .

4 8 N . N W N ov. 1 0 . 2 79 . 1 to N o 3 W v. . .

N ov. 5 . 94

Nov. 9 83 3 3 S . to

N v 1 1 1 20 . 5 8 W . to N o . 7 7 79 0 N

N ov. 1 3 1 1 0 5 85 S . to

N ov. 1 5 7 86 83 25 N . N 22 4 W ov. 1 78 95 N . to N

In addition to the resul ts given above some in teresting observations f were made by Mr . Suydam as to the effect of di ferent wind and barometer conditions on the air in the drift of the Mary McKinney i i mine as ndicated by candles and acetylene l ghts . These data are 8 wi shown in Table , follo ng . N RO K S RA A RI LE REEK DI S TRI T . 5 GAS I C T T , C PP C C 9

- e ee o wind and barometer conditions o n air in dr t o Mar LE 8 Data re ardin t TAB . g g fl f if f y McKinne mine y .

Strength

S Mi Mine cl osed e aus e o fs trata as . . to ld b c g

A ir in drift. N . to N . E good

S m e as in dn ft . N E . to N d o s a a . o tr t g

N E to N S on od . . . tr g Air gp S . to s C a m 0 . W . l

N t o N . W M D o. . ild

D o . S s E to . - . do m S m e t t as in drift do . . C a . o s ra a . _ l g

d o D O.

N t N . W d o o . N E L t o . ight m N to N . C W . al

S W . S B . t . is o to w . . r k

N ov 2 . to S . . to M . W W ild N . W .

S to S . W d . . o

N to N . W d -. o

N t N d W . o o

n Regardi g those samples that were collected and analyzed , the total number of samples collected was too small to permit the draw i 6988 ing of r gid conclusions . With one exception (sample No . ) the largest amounts of carbon dioxide and the smallest amoun ts of oxygen were found in samples collected when the wind was from the o f south or southwest . This relation agrees with statements some mining men that when the wind came from the south or southwest e the most rock gas entered the min s . Table 7 shows that rock gas was present In the north drift of the Mary McKinn ey mine when the wind was south or s outhwest in 4 2 Al in 1 0 cases and when it was north in cases . so cases the air was in f 3 good the dri t when the wind was from the north , and in cases l when it was from the south or southwest . A so a consistent relation could not be traced between the barometric pressure and the presence of rock gas ; Some of the mining men of the Cripple Creek district have a theory that when the wind comes from the south or southwest it sweeps up c canyons where the ro k outcrops . These , being somewhat porous , an permit the entr ce of atmospheric air , which forces the rock gas in n s to the mi e working . K D M P I N M I N E 6 0 B LAC A S .

C OM PO S I TI ON OF S TR AT A G A S S AM PLE S C ALC ULA TED ON A IR -FREE B S I A S .

It was impossible to procure samples of pure strata gas as it issued - from the rocks in the Cripple C reek mines durin g the visit of one of s E n the author . ntra ce was made as far as it was possible to pene dr trate into some of the ifts that were most affected . A sample

‘ ‘ i 2 . 69 (No . 760 ) containing per cent oxygen was obta ned from the Cresson mine and was the sample containing the largest percentage U e 1 of strata gas . ndoubtedly if one had been able to p netrate 5 or 2 0 feet farther into the dr ift a sample practically devoid of oxy can mi r gen could have been procured . One deter ne ather closely the composition of the strata gas , however, by selecting those samples that contained the smallest percentages of oxygen and calculating h - has in : t em air free , as been done in the follow g table

- n o am l containin sma ll e centa e o ox Airfree compositio f s p es g p r g s f ygen .

MI N E MI D GET .

To tal .

t P er ent. P er ent. P er ent. P er ent. P er ent. P er cen . c c c c c

1 0 . 86 0 . 0 0 1 0 0 . 0 0 1 8. 3 7 _

8 . 68 1 0 86 0 0

. 0 0

MI AN AC ON D A N E .

M R MC K INN E MI NE A Y Y .

C RESSON MI NE .

These calcul ations S how that the composition of the strata gas vari ed between and per cent of carbon dioxide an d ce of and per nt of nitrogen . The average of all the results is dio i . i per cent of carbon x de and per cent of n trogen . s i ni Thu , the rock gas is a mixture of carbon diox de and trogen . In making the calcul ations it was assum ed that no oxygen is present '

GA S I N RO K S TR RI LE REEK DI S RI . C ATA , C PP C T CT 6 1 in the the gas as it issues from the rock, and that any air in samples i — was due to d lution of the rock strata gas by the air of the mine . This assum ption appears to be justified because in a drift more or less filled with rock-strata gas the gas becomes less and less diluted with oxygen as one travels from the good air of the mine farther and falrther into the bad air of the drift . A tendency was noticed among the mining men of Cripple Creek to speak of the strata gas as carbon dioxide or at least as if carbon

i w as n n . hi d oxide the predomi ati g constituent T s is not the case .

' Nitrogen is much in excess . The bad effects produced are principally due to the fact that the rock gas s o dilutes the air of the min es that the oxygen falls to a point where lights will not burn or so low that life is endangered . In the authors ’ opinion the acetylene light should not be used as n of the sole warning agai st the presence gas in these mines . It is true that where the acetylene lamp burns there is enough oxygen 1 2 1 in f ( to 3 per cent) the air to support li e , but under such conditions the air only a short distance beyond in a drift or at the floor may be Th e n ff fatal to life . warni g of a candle flame a ords a much wider the O margin of safety . At some mines perators allow no work to be performed where a candle will not burn .

EFF E T ON M EN OF P RTI L PRES S RES OF O" YG EN C A A U . The effects of carbon dioxide and oxygen on men and lights have i been discussed in a previous part of this report . A po nt that can be profitably emphas ized here is the effect of the partial pressure of the oxygen on men . The effects of working in bad air of the Cripple Creek mines are typical of the effects produced by an y low oxygen and high carbon ’ in dioxide atmospheres . After a day s work the men suffer a feel g of n oppression , heavi ess , and lassitude , or sleepiness , and a loss of appetite , the degree of distress depending , of course , upon the extent h . W of vitiation of the air en the air gets very bad , say when a an c dle will not burn , slight exertion causes breathlessness . Much exposure in bad air brings on headaches an d nausea and complete r exhaustion . That more fatalities do not occu is due to the fact that the men fairly Well appreciate the warnin g of their lamps and r wi are careful about ventu ing where acetylene lamps ll not burn . in Collapse may be very sudden atmospheres low in oxygen . In -oi i fact , it is typical such atmospheres , that little warn ng is given of their great danger . In some cases men who have collapsed and n ff been rescued have been days recoveri g . The after e ects are very n similar to those produced by poisoni g by carbon monoxide . B LA K D M P I N M I N E 6 2 C A S .

C OM PARI S ON B ET W EEN THE I N D I C ATI ON S A FFORD ED B Y C A N D LE A ND L N E LAM E A ND A N AL E OF THE M PLE Y ET E S S . S S B A C Y F Y A . At each place where samples were collected by one of the authors

“ th e his he made a note of condition of lamp flames , both candle and s r acetylene . It is intere ting to compare these obse vations with the ll n : oxygen percentages of the various samples , as in the fo owi g table

lation o ox en contents o sam les to bu n o c l t l D a ta sho wing re f yg f p r ing f and e and ace y ene lam la p f mes .

I D ET N E M G MI .

Oxygen C andle Sam e N o . in Sample N o . pl burned . m . m sa ple sa ple.

N N D N E A AC O A M I .

R MC K I NN E MI N E MA Y Y .

C RE SSON MI N E .

Feebly .

In general these results show that the candle flame became ex tin uished 1 7 1 8 g when the oxygen in the atmosphere fell to to per cent , and that the carbide flame was extinguished when the oxygen con 1 4 tent fell to 1 2 to per cent .

M B STI B LE G A S I N THE - S C O U ROC K TR AT A G A S . Eight of the samples examined contained traces of combustible gas . The largest proportion was per cent . Presumably all of the samples contained small proportions that could not be detected by analysis . The relation between the contraction and the carbon i e i hi diox d content ndicated that t s combustible gas was methane . I L I ON ON DI I ON S OF M E A L M I N E VEN T AT C T T S . 63

Rarely a small outburst of gas is encountered that burns when a torch is applied to it, but quickly burns itself out .

V E N TI L A TI ON C ON D I TI ON S OF 1 5 M E TA L M I N E S A S I N D I C A TED B Y A N A L S E S OF A I R S A LE Y M P S .

In Table 9 following are shown data regarding samples of air col lec ted in 1 5 metal mines . Most of the samples were coll ected by in M lfl . e . Wo H . M , mining engineer of the Bureau of ines Some wer E i l . col ected by dwin Higgins , also a m ning engineer of the Bureau

The samples were analyzed by the authors . The table and the i il comments follow ng touch upon the vent ation in the different mines . Cal culations to Show the amount of black-damp present were made only for samples that were not affected by blasting operations in the mines . B LA K D M I N M I N ES 64 C A P .

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B L C K D M P M I N E 6 6 A A IN S .

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3 3 . V T T T OF T EN ILA ION CONDI IONS ME AL MINES . 71

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w m u w 0 N n w m 8 m w $ 0 $ 0 8 $ e 8 w w w w ? 3. i. 3 “. 2. w 3 . 3 3. 3 3. B LA K P I N 72 C DAM MINES .

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DA M P I M I N E 74 B LACK N S .

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9 8 7 1 0 0 O 7 T T ON DI I ON S OF M ETAL VEN ILA IO N C T MINES . 75

4 6 6 1 0 1 B DA M P I N S 76 LACK MINE .

T ON R U T F COMMEN S ES L S O ANALYSIS . to

l 4 air On y one of the samples (laboratory No . 60 9) of from Mine 1 c ontained a proportion of oxygen that was either low or excessive as i c ompared w th the oxygen content of ordinary air . All of the sam l ples were col ected several hours after blasting operations . Hence the mine air W as not vitiated in any appreciable degree at the time the samples were collected . All of the temperatures observed at the hi — time of sampling were gh too high to allow men to do good work .

2 . 4 0 3 6 Of the samples collected in Mine , four (laboratory Nos , 4 0 3 7 4 0 5 2 4 0 5 diox , , and 6) contained excessive amounts of carbon l ide . These samples were all col ected at the same place , a few minutes apart . The atmosphere contained powder smoke as the l vi resu t of a pre ous blast, hence the atmosphere was vitiated by ‘ - l r products of combustion from the blast . Wet bu b temperatu es - r were not noted in this mine . The dry bulb temperatu es were good except that observed at the time of taking the sample designated 4 - l laboratory No . 0 79 . The wet bu b temperature was not deter in n l hi mined con ection with the co lection of t s latter sample , but the sense of discomfort experienced by the sampler and the moist con dition of the place of sampling indicated that the air was almost 4 . 79 saturated with moisture Sample 0 was the only one , not con tam inated i with products of combustion from a blast, that had a h gh percentage of carbon dioxide . The analyses of two of the samples collected in Mine 2 were recalculated to show the percentage of black damp present . ° - Wet bul b temperatures observed in Mine 3 exceeded 75 F . The chemical analyses disclosed no low oxygen or high carbon dioxide 1 2 content . The composition of the black damp ranged from to per cent carbon dioxide and from 88 to per cent oxygen . The temperatures and the humidity readings observed in Mine 4 were excessively high . The chemical analyses of the air disclosed no bad condition . Black damp contained to per cent carbon dioxide and to per cent oxygen . The temperatures were higher in Mine 5 than is compatible with in ffi the best work g e ciency . The chemical analyses disclosed no a high carbon dioxide or low oxygen percentages . The bl ck damp contained to per cent carbon dioxide and to per cent nitrogen .

n 6 7 8 9 . Favorable temperatures were fou d in Mines , , , and The chemical analyses of the air also showed good conditions . 1 Temperatures in Mine 0 were not so good . 1 Most of the observed temperatures in Mine 1 were good . There was one noteworthy exception , that noted at the time of taking sam

443 . ple 8 The carbon dioxide content was also high in that sample . VEN I L I ON ON DI I ON S OF M E AL M N T AT C T T I ES . 77

Considerable powder smoke was present at some places where sam ° were coll ected ples , but no carbon monoxide that might have re a n mained in the air fter the shooti g was found . Of 1 2 Many the temperatures observed in Mine were low . Som e ° l . exceeded 75 F . wet bu b The carbon dioxide and oxygen contents s 4463 44 4 in some of the amples were low, especially in samples , 6 , 4 J O and 4 73 . ust how much blasting perations affected these sam

NO . ples is problematical . One sample ( collected 1 1 hours

after blasting , contained per cent carbon dioxide and per

cent oxygen . In general the chemical analyses of the samples from Mine 1 2 disclosed higher carbon dioxide and lower oxygen contents m than in the samples fro any of the other mines .

The temperatures in Mine 1 2 were favorable . O 1 4 1 5 The temperatures bserved in Mines and were good . Only in Mine 1 2 were samples collected that contained excessively high per Of centages of carbon dioxide or excessively low percentages oxygen . ' m bs m e aid In su ming up conditions in these metal ines it can that , s ll as regards the chemical analy es of the samples co ected , the air , on o the whole , was very good . Samples c llected several hours after s blasting, and when men were mucking out their place , did not con i O tain carbon monox de from the blasting perations . Changes in the mi O mi air of metal nes due to xidation are not as rapid as in coal nes , in spite of the fact that immense volumes of air sweep through coal in o mi il r m es as c mpared to metal nes , where the vent ation is natu al - or where air is supplied from compressed air lines . hi i - The c ef trouble lies in the h gh temperatures , both wet bulb and dr - ul y b b also , the stagnation of the air encountered in many places is so bad as to be detrimental to the health and to the efficiency Of the workmen .

OB SERV TI ON S RE G RD I N G B D M P I N ERT I N M ETAL M I N A A LACK A C A E S . The average percentage of black damp in certain mines and the average composition of the black damp are shown in the following table :

a e ce ta e an ave a e com osition o black am t i A ver e n d d in cer a n metal ine g p r g r g p f p m s .

C omp osition Of black m da p . n N Mi e O.

2 and

0 0 0 0 0 0 0 0 B LA K D M I N M I N ES 78 C A P .

The average of all analyses in the above table is per cent black damp with a composition corresponding to per c’ent carbon dioxide and per cent nitrogen . The average com position of black damp in metal mines is about the n A same as that fou d in coal mines . difference in its occurrence in the two kinds Of mines lies in the amoun t that can be produced in a given time . If coal mines depended only on natur al ventilation or on compressed in n air from pipes at work g places , the amou t of black damp produced would usually exceed far more than it does that produced in metal ne i l mi s , for coal reacts w th oxygen much more rapid y than do most i of the rocks , wood , etc . , found in metal m nes .

S U BI M A RY .

The most satisfactory definition of the term “ black damp is an accum ulation Of carbon dioxide and nitrogen in excess of the per r centage foun d in pur e atmosphe ic air . The principal factors that affect the changes In min e air are (1 ) the velocity with which the mine air traverses the min e passages ; (2 ) the amount Of coal with which it comes in contact ; (3 ) the gaseous (methane) nature Of the seam ; (4 ) the natur e Of the coal as regard its power to react with oxygen ; (5 ) the temperature and the wetness

Of the mine . Carbon dioxide mus t be present in large proportions before it Of 3 4 thr eatens life . A proportion to per cent of carbon dioxide in

in . air affects the breath g of most people Men may , however , work ffi for a long time in such an atmosphere , although their e ciency as workmen will be greatly affected and they will become fatigued in 1 2 quickly . The presence air of as little as or per cent of carbon dioxide is not so much a matter of safety and comfort to those who fi m breathe it as it is of their ef ciency as work en . Distress is caused in some people when the oxygen content falls to less than 1 3 per cent . Rapid breathing is produced much more quickl y by an excess Of carbon dioxide than by a corresponding f deficiency O oxygen . The important point to remember is that rapid breathing caused by carbon dioxide starts long before there is fi any serious danger , whereas rapid breathing caused by a de ciency of oxygen is a grave symptom and points urgently to serious danger . By acclimatization people live the year round at high altitudes where the air has an oxygen content , by weight , that is the same as that Of an atmosphere at sea level containing 1 2 per cent oxygen by n volume . People u accustomed to such atmospheres , if suddenly

e . m plunged into them , xperience severe distress In an experi ent conducted by the authors a man lost consciousness temporarily when the oxygen content Of an atmosphere he breathed fell to 7 per cent . SU M M R A Y. 79

Mice and canaries are about as resistive to low-oxygen atmos pheres as men ; hence they can not be used by exploring parties to Of lo give warning atmospheres that are dangerously w in oxygen . An excess Of oxygen or a diminution of oxygen such as often occurs in many mines , if present in buildings above ground Where people Of congregate , would be indicative extremely bad ventilation . How in ever , mines having such an excess or diminution the ventilation

. t may be excellent In most buildings above ground , he problem of good ventilation is not to correct a diminished content of oxygen or Of an increased content carbon dioxide , but to maintain prop er temperature and relative humidity, and to keep the air moving , al Of an Of though the presence excessive proportion carbon dioxide , f more than or per cent , may be a reliable indication O air that will produce injurious effects on men . In these buildings the carbon hi e dioxide comes c efly from the air exhal d by the persons present , and , if fresh air is not admitted , invariably accompanies bad condi tions such as stagnant and oppressive air , high temperature , and fre

. . quently high humidity In , coal mines the carbon dioxide is princi pally from the action of the oxygen of the air on the coal , and per f Of cent is requently found in the cool , swiftly moving air retur ns Of where or more cubic feet air is passing per minute . Hence , a proportion that accompanies good conditions of ventilation in a coal mine may indicate extremely poor conditions Of ventilation in the room of a house . Th A S imilar statement applies to oxygen . e oxygen content is scarcely ever normal in a coal mine , owing to the gas being absorbed 1 by the coal ; in fact , a diminution of per cent is not uncommon . Such a diminution in a building filled with people would be aecom

anied . p by intolerable conditions of ventilation However , even in coal mines the oxygen content Of the air shoul d not be allowed to become too low, and the authors believe that it should not fall below l 1 9 per cent . That this limit can easi y be maintained in coal min es - is indicated by many mine air analyses made by the authors . The maximum percentage of carbon dioxide allowed in English coal mines i s per cent . The principal cause of the depletion Of oxygen in coal-mine air and the increase of carbon dioxide is the reaction between the oxygen Of the air and coal . Some of the oxygenis actually held dissolved in the coal substance . Part of the oxygen is converted into water , part x into carbon dio ide , and part (by far the larger part) is retained as combined oxygen to give compounds richer in oxygen than the coal

Of . itself . Part the carbon dioxide is retained by the coal Explosive proportions Of methane in air become nonexplosive when th e proportion of oxygen in the atmosphere falls below about 1 4 per . cent . Carbon dioxide has only a Slightly greater effect in reducing B L K D M P I N M I N ES 80 AC A . the explosibility of methane- air mixtures than nitrogen has ; for n 2 0 instance , when the oxygen is kept consta t at per cent , part of the nitrogen must be replaced by 1 0 per cent Of carbon dioxide to raise the low limit for methane from to per cent . The specific gravity of black damp varies considerably in certain mix tures . When methane is present the combined gases may be ul O lighter than air . Great caution sho d be bserved when one detects ul l an accum ation of black damp of lighter density than air, especial y in n ns coal mi es in which naked lights are used , as this lesser de ity is probably due to the presence of methane . E fire mi fire xcept directly over a area or close to a ne , a large pro portion of carbon dioxide (more than 3 to 5 per cent) is unusual in air f the O a coal mine . An oil-fed flame becomes extinguished when the oxygen in air falls to about 1 7 per cent ; an acetylene flame 1 s extinguished when the 1 2 1 oxygen falls to about or 3 per cent .

Lack of oxygen is the important factor in extinguishing lights .

In some experiments conducted by the authors , the oxygen content n fell to per cent before the flame became exti guished , but the presence of 1 0 per cent of carbon dioxide raised the extinguishin g percentage of oxygen to A tmospheres that do not contain enough oxygen to support an Oil fed flame (about 1 7 per cent) may be explosive when the oxygen 1 4 content is as low as per cent , if enough methane is present . When a burning part of a mine has been successfully sealed the composition Ofthe atmosphere within changes . The oxygen decreases to a proportion (probably about 1 7 per cent) that will not support flame ; ultimately the Oxygen content becomes S O small that the rate Of combustion is extremely low, so low that combustion entirely air is ceases , the embers cool , and the admission of when the mine reopened does not rekindl e them . 1 1 1 2 9 n In samples of gas from mi es represented , the average per centage of carbon dioxide in the black damp was per cent , and e a f ni the average p rcent ge O trogen per cent . In 6 mi nes of 2 2 examined the temperature was higher than it 0 l 75 F . e should be ( , wet bu b) und r the best ventilating conditions . e a S n Analyses of a larg number of s mples , how how mine air cha ges as it traverses the workings . The average co mposition of the black o damp was per cent carb n dioxid e and per cent nitrogen . E s i d xcept for two or three amples , in wh ch carbon ioxide was high

and . the oxygen low , the quality of the air was good A s n f regards the u favorable e fect of black damp on men, on lights , and i - air r i Of on the explosibil ty of methane mixtu es , the d minution a Of oxygen in the tmosphere , resulting in the formation more nitrogen , is mainly responsible . The presence of carbon dioxide is far less

P UB LI CA TI ON S ON M IN E A CC I D E N T S A ND fMETHOD S OF COA L M I N I N G .

Lim ited editions of the following Bur eau of Mines publications are

tempor arily available for free distribution . Requests for all publica t ns no t o io can be granted , and applicants should select nly those f Al publications that are O especial interest to them . l requests for r r r Of publications should be add essed to the Di ector , Bu eau Mines ,

hin . . Was gton , D C

E . n l B LLETI N 1 7 A im e on ex l osiv es for coal mine s b. Munro e a d aren e c U pr r p r , y C C l l i i Hall 1 . 1 0 s . 1 2 fi Re int Of nite tates eo o al Su ve l n 6 s . d S G c Bul et . pp , p , g pr U g r y

423 . l i i i i i l t f oal st . . R e th h a te s . LL TI The ex os O c u G S c w c . C W . B E N 20 . b b b U p y d , y , p r y J 4 4 l 2 fi s l en an Haas and a l S ch l z 20 . 1 s . F aze Ax e La s F o . 8 . r r , r , r k , C r pp , p , g L TI N 42 The sam lin and examination o f mine ases and natu al L E . b B as U p g g r g , y i 1 1 . 2 l l n M . e t . 1 3 . 1 6 e . 23 fi s l a d F . Se 9 . A . . Burre G b r pp , p , g LL TI N 4 and availa l e for fil lin mine wo in s in th e No the n Anthra ite BU E 5 . S b g rk g r r c l n 1 1 . Da to . 3 . 3 3 s . fi s l H. s v ni a bN . 9 8 5 . oal Basin Of enn a C P y , y r pp , p , g i i f x l si n- r min m s H H. l i s t on O e o o oo e oto b. 4 An nve t a a . LLETI N 6 . BU g p p f r , y C rk

l 4 fi s . 4 . s . 1 1 91 2 . 4 6 pp , p , g 4 The sel ection of ex l osives u sed in en inee in and minin O e a BULLETI N 8 . p g r g g p r l l l 1 1 3 . 50 . 3 s . fi s Howe . 9 7 . tions bla ence Hall and S . . , y C r P pp , p , g t Of the inflamm abilit of coal dust l at s ud b A a o o . . TI N 0 W . BULLE 5 . b r ry y y , y J C

ll r 1 1 0 . fi S cho . 3 . 6 5 s . A . 9 9 H man and L . F aze E . . o r r , J ff , , j pp , g i i min ases bthe lam ents o fincandes en l I n t on of e c t e ect ic lam LLETI N 5 2 . s BU g g y fi r p ,

1 . l 2 fi s . 1 1 . 6 s . I l sl . 9 3 3 l and L . . e H H. a b. y C rk C y pp , p , g Fi st se ies Of coal -dust ex losion tests in the ex e im ental min LLETI N 5 6 . e BU r r p p r , L l m n and W . . E . 1 1 1 1 K . e e t 9 3 . 5 1 2 l M . ones . . s . Ri e L . bG . S . c y , J , J C , gy pp , p , fi s 2 8 g . 0 H rau li c mine llin its u se in the enns lvania anthracite elds B ULLETIN 6 . yd fi g; P y fi ; 1 l 2 3 . 1 fi s l Enzian 1 3 77 . s ha s . 9 . b e . elim inar e o t a pr y r p r , y C r pp , p , g 2 N tional mine- escu e and first-aid confe ence itts ur h Pa Se 6 a . B ULLETI N . r r , P b g , , p — i 1 1 4 2 H M W lson 9 3 . 7 . 1 1 b . . b23 26 9 . em e pp t r , , y bH H l El t ic switch es for use in aseou s mines . . ar and R W 8 ec . . BULLETI N 6 . r g , y C k ls 6 . 1 3 40 . 1 9 . Crocker . pp , p Goal mine accidents in the nited States and o ei n countries com BULLETIN 69 . U f r g , 2 4 fi s 1 l . 0 3 s . n 1 91 3 . 0 . W Ho to . F . p p , g b. pile d y r p Mine ventilation sto in s with es ecial re e ence to coal mines in B ULLETIN 99 . pp g , p f r 1 l 4 fi 1 4 s . s 3 0 . m 9 5 . Y Willi a s . R . i b. , , n pp g I lli o s, y p f urnin f fuse as influ enced btem n Th e ate o o e atur e a d T EC HN I C AL PAPER 6 . r b g y p r 1 1 2 28 o e . 9 W . O Smellin and . W . b. p pp ess u e pr r , y g C C ’ n f u se and mine s s uibbl n l I nvesti a tio s o s are ce Ha l T EC HN I C AL PAPER 7 . g f r q , y C

2 1 . well 1 91 . 9 Ho . and S . P . pp d bi s for dete in a on n xi ER 1 1 The use of mice an ct c m o o de T EC HN I C AL PAP . rd g rb ll A Burre . . bG . . nd ex losions after mi ne fires a p , y pp n aid 1 1 1 htin m ine es bG A Bur 1 Gas anal sis as a . . T EC HN I C AL PAPER 3 . y fig g fir , y 1 1 fi . 1 1 2 6 . 9 . M Seibe t . nd . r ell a F . r pp g 82 B LI TI ON S ON M I N E I DEN S PU CA A CC T . 83

L PER 1 4 A a a u f r - n l l s b I C t s o as a al sis abat ies at oa mine EC HN . o o c T A PA pp r g y r r , y eib 1 1 l nd F M S e t 24 fi l a . . . 9 3 . . s A Bu e 7 . G . . rr r pp , g L PER 1 T e e e t Of stemm in n i f x l sives b h e EC HN I C 7 . c o t e c enc o e o T A PA h ff g ffi y p , y n n la n e Hall 1 1 2 2 1 1 lli d e c . 9 0 fi s Sne a . . O . W . . g C r pp , g L PE 1 8 Ma az in es and th aw h u f x l i l Hall EC HN I C R . o ses or e os ves ba ence T A PA g p , y C r 1 2 3 4 1 l fi l 1 . s H e l 9 . . 5 nd S ow . . a . P . pp , p , g I L PER 1 The acto of sa et in mine el i al ins ll n b E io s C HN C 9 . ect c ta at T A PA f r f y r , y 1 1 2 1 4 l . H H a 9 . . . C rk . pp E I C L PER 21 The evention Ofmine ex l osions e and m m enda C HN . o t reco T A PA pr p , r p r i o Wa tte n e arl Meissne and A thu Des o ou h 1 2 R int i ns bV ct . . e t o , y r y , C r , r r b r g pp pr l S Bulletin 3 6 of United States Geologica u rvey 9 . 2 El al mbols for mine L PE 2 t ic s m a s bH H l R 1 1 2 EC HN I C . ec . . a 9 T A PA r y p , y C rk . . 1 1 8 fi s pp . , g . n f ine as bnd d n n EC HN I C L PER 28 I nitio o m sta a i ca descent lam s b T A PA . g g y r p , y 1 2 l 1 6 . H H a 9 . . . C rk . pp E I L PE 29 ainin with mine- escu e eathin a a atu W HN C R . s b C T A PA Tr g r br g pp r , y J . . l 1 1 2 1 au 9 6 . P . . pp Th infl m a le ases in air b I L PER 3 e am mine G A Bur ell n EC HN C 9 . . . a d T A PA b g , y r 1 2 2 fi s 1 3 4 . M eibe t 9 . . F S . . . r pp , g I C L PER 43 Th e e ect of ine t ases on inflamm a le aseou mixtu e EC HN . s s T A PA ff r g b g r . l n 1 1 3 24 1 l 8 fi s m e t 9 . . . K e . . b . y J . C pp , p , g L PE 44 et el t i wi che for n s bH H l R S s t s mi e a 1 1 EC HN I C . a ec c . . 3 T A PA f y r , y C rk . 9 . 8 pp . L PE 4 o ta le electri mine lam s bH H l 1 1 EC HN I C R 7 . . . a 9 3 T A PA P r b c p , y C rk . .

1 3 pp . E 8 oal -m ine accidents in the nite State 1 8 —1 1 EC HN I C L P R 4 . s 96 9 2 with T A PA C U d , , 1 1 2 m iled b Ho n 1 1 4 i f r co F W to 9 3 1 fi st . 0 s hl stati cs o 9 . . . 7 . ont . m y , p y r pp , g I L PER 5 8 The action Of acid min e wate on the insul ati n f el e i TEC HN C A PA . r o o ctr c l in H H la I lsl 1 1 2 i e o t b d L . m a . an C . e 3 e 9 . 6 n u to s a . . . c o d c r ; pr ry r p r , y C rk y pp , 1 fi g . L PE i si le ele t i l am s for in bH I R 75 erm s c c m e s H la EC HN C . . . T A PA . P b r p r , y C rk 21 3 fi s 1 1 4 . . 9 . pp , g I L PE s n th sam lin and anal sis Of al bA ld 6 Note o e co . ie E HN C R 7 . . F T C A PA p g y , y C fi 1 1 5 9 . 6 s . n r 9 4 . e . pp , g L PER 7 Re o t Ofth e om m ittee on Resu scitation om Mine Gases E HN I C 7 . T C A PA p r C fr , W ile ose h E lan e Yandell Hen e s n and S W B annon Geo e . o . . b. . y C , rg Cr , J p r g r , d r , T 4 fi s eltze 1 91 4 . 3 6 . . M r . pp , g E 4 Meth ods Of reventin and limitin ex losions in coal m ines E I C L P R 8 . T C HN A PA p g g p , n 1 1 4 1 4 l fi 9 5 5 s . 3 s nd M o es . . . . Ri L . G S ce a . b . y . J pp , p , g 1 is ibl ex losi e tes ed i M 1 1 1 b I L PER 0 0 erm s e s t o to arch 9 5 E C . T C HN A PA P p v p r r , , y 1 1 1 H well 5 5 . 9 . S o . . P . pp 1 h o rin in coal m ines bele t icit nt olled om I L PE 0 8 S t c co TEC HN C A PA R . fi g y r y r fr B h and M Means 1 91 3 H l a N V et . 5 6 h i e bH ...... d . t e ou ts . , y C rk , r , C pp ’ I R L R 5 E lect ical accidents in mines thei cau ses and evention MI ERS C . N C U A r , r pr , n H R nd l h 1 1 1 1 R L I lsl e a d F a o 0 . D o ert s 9 . H H la . . . . . b W . . y . . C rk , b , C y , p pp , ls 3 p . ’ f x l i in b Rut inin M E s IRC UL R 7 Use and misuse o e os es coal m . . I N R C A . p v g , y J J 1 8 fi 1 1 4 5 s . le e . 9 . dg . pp , g ’ - W l ow W A n in b . id in i for e M G as . I L 8 F i st a st u ct o s m s . . I N ERS RC R . M C U A r r r , y g , n R bs 1 1 3 6 5 1 fi s 7 h d O o e t 9 . . R nbu s a . . . au e . d , C r pp , g ’ in n i L M ones 1 d n ars a d lo o o b . 1 A i s om m e c c m t es . . I ERS I RC L R . cc e t M N C U A fr v , y J 1 1 2 1 6 9 . . pp B LA K DAM I N M I N E 84 C P S .

’ ’ ER I R L R 1 2 Use and a e Ofm ine sa et l a b l 1 s m s W au 1 3 MI N S C . c . . 9 C U A r r f y p , y J P . . 1 4 fi 6 pp . , g . ’ E I R L R 1 4 G ase s ou nd in oal ine b ll nd m s G A Bu re a M MIN RS C . c . . F C U A f , y r . . ibe 1 1 4 23 Se t 9 . r . . pp ’ ERs I RC UL R 1 5 Ru les for ine- es u e and fir -aid eld ontest bW MI N m c st c s C A . r fi , y J . . l 1 1 3 1 2 au 9 . P . pp . ’ I RC L R 1 Hin s o n oal - in v n ila i n b led e 1 1 4 6 t c m e e t t o Rut 9 MI N ERs . . . . . C U A , y J J g 22 pp . ’ MI N ERS I R C L R 21 What a m ine c an do to event ex losions Of as and coal C U A . r pr p g u st bG S Ri e 1 1 5 24 c . 9 . d , y . . . pp INDE" .

Pa e g . B a am ana ses of 3 3 48 77- 78 80 81 l ck d p , ly , , , , A en s mine at Lo e Mi C o e ccid t , , dg ll lli ry I n me a mines om os on 77—78 81 t l , c p iti , in C i e C ee is r ppl r k d trict e en a e of 77—78 81 p rc t g , e ene f x , o o on o in e p os ve mix Ac tyl pr p rti , l i deaths from 1 2 ures t definition Of A e ene ame ex n uishin Of e ease c tyl fl , ti g g , by d cr e fe of on s 80 f ct , light Of ox en 28 3 0 , 80 — yg on men and animals . 80 81 e ene am use I n e e n mine as 61 , g m -a c tyl l p d t cti g n o o A o e an ir mi x u s o 80 th e t re o o o o o o o o o e am e e on Of 1 4 Aft rd p , d t cti o ma on of 6 26 42 f r ti , , A ir at sea eve e en a e of ox en in 1 0 , l l , p rc t g yg in m ne air e enta e of 48—49 66—71 76 77—78 i , p rc g , , es a ne ess for mine s 1 8 fr h , c ity r inflammabilit Of es u s Of es s 23 y , r lt t t — — in oa mines ana ses of. 41 44 47 c l , ly , s e av of va a on of 26 80 p cific gr ity , ri ti , a am I n e en a e of 48—49 bl ck d p , p rc t g term not s ynonym for carbon dioxide 81 a on ox e in e en a e of 27 48 c rb di id , p rc t g , S ee also C arbon di oxide; N itrogen; Oxy c om osi on of an es in 5 22 . , n p ti ch g ge . ea a e of effe of 50 l k g , ct B as in ih me a m nes effe on air 76 77 l t g, t l i , ct , ox en in a of 28 yg , l ck B ea n e fe on e ease of ox en 9—1 4 r thi g, f ct , by d cr yg , e en a e Of 48 49 50 p rc t g , , 1 7 78 S ee also B m a a . l ck d p of a on ioxi e effe of 9 78 c rb d d , ct in m e a mi nes ana ses Of , H r n a t l ly S ee als o ype p m . m in a da , e en a e of bl ck p p rc t g Bu e Mont m nes at ana ses of air in . tt , , i , ly m ne an es in auses Of i , ch g , c ex os of efl ect Of ox en on pl ibility , yg ’ um of eflect of h idity , a man o n n n a on in En a infl mm b C , , o ve t s co l a a ili t Of esu s of es s d h til i gli h y , r lt t t J min es o o o o o o o o o o o o o o o o o o p urity of o o o o

C an a es e fe of ox en a on n n n n n n n n n wa e va o in a so on of ri , f ct y g l ck t r p r , b rpti use of in ex o n m nes ure ana ses of , pl ri g i p , ly ’ C an d e ame ex n u s n of es s o o am e eflect o f ex n u s n a m os l fl , ti g i hi g , t t Alc h l fl , ti g i hi g t use Of in ete n m ne as ph eres on , d cti g i g

m x n shin of o C a e a e e u o o o o o o o o o o o o o A na on a m ne es on of. rbid fl , ti g i g c d i , d cripti C a on iox e a on of on me ane-air as in ana ses of rb d id , cti , th g , ly

m x s o o o o o o u e o o o o o o o o o o o o o o o o o 24 sampling of i t r o o o n a n i o o o f n o s s ems o 1 5 effe o ve o o o o o o h s in effe Of ox en on ct , til ti y t lig t , ct yg

m n an s o o o 2 61 on e d o o o o o o o o o o o o o 9 78 A na ses of a am , ly , bl ck d p light

in a am e en a e of. 42 in m etal mines bl ck d p , p rc t g , 49 76 77 of coal-mine air in oa m nes am oun ven off 25 of as om na on a m ne , g , fr A c d i c l i t gi n ease of 1 9, 79 from C resson mi ne . i cr en a of 4 48 4 M e e 3 , , 9, 80 from ary McKinney m inez. p rc t g sources of 6 1 6—1 7 in C e C ee m nes 61 Ofinflammable m ix tures rippl r k i - in En s oa m nes e en a e Of 79 ofm etal mine air gli h c l i , p rc t g in un s egul a on Of 7—8 ofpure air l g , r ti in m x ures ex n u s n am e e en A sh saw us . S ee S w , d t a dus t . i t ti g i hi g fl p rc t

a of o o o o o o ge o o o o o o o o o o o o B . n n om o so o o o o o o o o p i i g fr o o o B a ome i essure effe of on ou ow of ese e of s n Of r tr c pr , ct , tfl pr nc , ig s a a as o ort on Of in norm al mine air tr t g pr p i , ox en essure o es on n to eten on of oa yg pr c rr p di g r ti , by c l B e Paul law on s o o a a on of a e m not s n on m for a am rt , , phy i l gic l cti t r y y bl ck d p ans e of in ea in tr f r , br th g n n w m C a on m onox e in ex os ve m x ures o a e s om lo a o e essu e . d g r fr b r tric pr r rb id , pl i i t , B ibliography on absorption Ofgases by coal . . 86 I N DE" .

’ C ar on m onox e flame eflect of ex n uis es mine e fe t of sea n on b id , ti g h Fir , , f c li g in a m os e es on ox en in air e fe on g t ph r yg , f ct a m v C on onox e o sonin ef e of. e en on Of. rb id p i g, f ct pr ti m mm a mix am e ex n u s in of C e en . K . on n a e u es l t , J , i fl bl t r Fl , ti g i h g on a nin ox en 2 25 ax flam e of e fe of ex n u s n t c t i g yg 4 Fl , , f ct ti g i hi g a on inflamm abi m an -air mix m OS h eres on il ty of eth e p .

G .

C oa a so on of ases o a . . l, b rpti g by, bibli gr phy a so on of ox en am oun Of G as anal ses o f om na on a m ne b rpti yg by , t , y , fr A c d i om C esson mi ne owe of o o o o o o o o o o o o o o o p r fr r o oxi a on Of ex e m en s on om Ma McKinne mine d ti , p ri t fr ry y rate of from Midget m ine C oa us a so on of ox en om us on of l d t , b rpti y g by c b ti C oa - us ex osions ven a on aus e of in o s a a C e C ee min n dis l d t p l , til ti c r ck tr t , rippl r k i g - ri — t ct o o o o a am fi f x n a m o o o o o o o o o o o o o o o o o o o o o o o 5 1 3 81 C o as e c ect o e uis in os o 6 l g fl , ti g h g t , h r n G as owe s in C e C ee s p e es o 3 0 bl r , rippl r k di trict 5 4 — — G as sam in n on C oa mines ana ses ofair in . 26 3 3 4 1 44 47 n a a 5 3 l , ly , pli g , A c d H in C esson m n m in am eo o o o o o o o o o o o o o a a oun o u e in l o 5 4 bl ck d p , t pr d c d r i a on x in n 79 in C e C ee m ines c rb dio ide i crease of. rippl r k percentage of 80 in Mary McKinney mine s ou e of 6 1 6—1 7 25 79 rc , oxidation Of air 77 ox en in En s law e atve to 1 7 yg , gli h r l i e u on of ex ans on of e e of a u e on r d cti p i , ff ct ltit d S ee also En s oa m nes I n i ana inflamm ahilit of mi s gli h c l i ; d ; y , li t Gases m ne s f Penns vania. ana es o yl , i , ly C om us on a e of efl ect Of ox en on en e fe of a m os e essu e on b ti , r t , yg c t t f ct t ph ric pr r on expl os ibility of Co m us on s on aneous even on f s a fi a on of o . b ti , , p t , pr ti tr ti c ti C onumdrum m ne ven a on in S ee a lso B a am C a on ox e i , til ti l ck d p ; rb di id ; C esson m ne om esse air in e e of C a on m onox e N o en r i , c pr d , ff ct . rb id ; itr g as in ana ses Of s o o a a on of law on g , ly phy i l gic l cti sam in Of G aso ne am e eflect ofex n u shin a mos pl g li fl , ti g i g t her on in fl of ox n es o o o o o o o o o o s e ect e on o o o o light , yg p o o Gaso ne va o in ex os ve mix ures e fe li p r , pl i t , f ct C e C ee minin s as in oc rippl r k g di trict , g r k

s a a in 5 1 G a am . I . on ox a on of tr t r h , J , id ti s C e s s av s . S ee Saw us . on ox en a so on oa us ypr h ing d t yg b rpti by c l d t . D . H .

D ou as C . G . on a on ox e efl ect of gl , , c rb di id , , Ha ane S n m a m . . o ea s o a . ld , J , d th fr bl ck d p on on effe of a on ox e on ct c rb di id breathing . E on n amma e m x . i fl bl i tures . on of sa e am in air low in En s oa m nes a on ox e in er light f ty l p , gli h c l i , c rb di id , p centage of ox en in l aw on s in air low in ox en yg , light yg e ommen a on of for an a fven E a o o am e effe of ex n u sh n r c d ti st d rd o ti thyl lc h l fl , ct ti g i i g a on atm osph eres on l ti o o o o o o o o o o o o o o o o o o o o Hem o aw s u S ee Saw u . E ene in ex os ve m x u es e e of l ck d st . d st thyl , pl i i t r , ff ct Hem e ex os on e e use of in inflam E ene am e efl ect of ex n uis n a m os p l pl i pip tt , , thyl fl , ti g hi g t mabilit es s ph eres on y t t Hen e son an e on ea n w de Ex os of m e ane eflect Of m n d r , Y d ll, br thi g ith p l ibility th , di i x n u ish ed oxygen creased o yge s pply n flect of a n ox n limits of o e c rbo di ide o breathing ‘ H e En e u e s an . S e Lo e M Ex os of m e ane-air m x u es efl ect dd r fi ld , gl d dg ill pl ibility th i t r , C Ofblack dam p on olliery . Hum e fe of on m ine air effect of oxygen content idity, f ct , H o en in ex os ve m x u es ef e of experiments on ydr g , pl i i t r , f ct H n am e fe f x u m s om e u on Of o e e, o e n shin a os ri k fr , r d cti ydr g fl f ct ti g i g t h n eres o o o o o o o o o o o o o o o o o o o o o o o o o Ex os ofmine air efl ect of Ox en on p o o pl ibility , yg H noea au e of Ex os ons mine ven a on ause of yperp , s s pl i , , til ti c c Ex os vem x u es of as and air x i S ee also B ea n o en n . pl i i t r g , yg r thi g ee al so M n - ir m S etha e a i xtures .

I nflammable as in oa mines an e of g , c l , d g r e m infl mm i I nflam ma ble m x u e nves a on of a a abil t of s s s esu o f es s Fir d p , y , r lt t t i t r , i tig ti w e ox en an a ses of ith littl yg , ly ox en e u e S ee a lso Me an -a m x yg r d c d th e ir i tures . I N DE" . 87

Pa e g . - - I nflammabilit ffi am e u s of es s of. M e effe ofl ow o x en m n o re s a os e e o 1 2 1 4 79 y d p , r lt t t ic , ct yg t ph r . , m m m I nfla abilit of a e m of. use of in ex in in s s s o es 1 4 y g , li it , pl r g I nflam mabilit ofme ane M e m ne es on of 5 2 y th idg t i , d cripti In flammabilit of me ane-air m x u es as in ana ses of y th i t r , g , ly — m s of 24 25 sam n of 5 2 53 li it pli g , I nflammabilit ofm ne air efiect ofox en on 80 s in effe of ox en on en on 62 y i , yg light , ct yg c t t resu lts oftests of 23 ventil ation system in 52 — I n ana oa m nes ana ses ofair in 46 47 M ne air. S ee in oa m nes in di , c l i , ly i Air , c l i ; Air , m e a m nes m ne B a t l i ; Air , i ; l ck am G ases m ne d p ; , i . Jo i en P n x n f m 3 0 —3 1 M n x rr s . . o e n o o a es e e os ons . Ex s n m S ee o o s ne . , W , ti cti fl i pl i pl i , i M ne m es . S ee es ne. K i fir Fir , i . M m ine e . S ee T m e m ne ti b r i b r , i . M — M n C m K e o ont m n at an f in 65 66 es . S ee oa nes Me a min e a ses o air es . ll gg, , i , ly i l i ; t l K e osene am e e fe ofex n u s n a m os Mo s u e n uen e of on a so on of ox r fl , f ct ti g i hi g t i t r , i fl c , b rpti y heres on en oa p . . g by c l

L . N. N a u a as in x s v m x f f e o e ur es e e t o . Law S ee En s oa m ne P nn l g , , s . gli h c l i s ; e sy t r l pl i i t f c Na u al - as flam e e fe of ex n u shin an a g , v i . t r f ct ti g i g a mos e es on 3 0 Lea S . D ak . m ne at ana ses of air d , , i , ly t ph r N o en in a am e en a e of 48 81 Lea a e of air in m nes effe itr g , bl ck d p , p rc t g , k g , i , ct in C e C ee m nes 1 L s a on ox e ven ofi . 6 ight , c rb di id gi by . rippl r k i extingu ishing of 0 . ox ygen consumed by Oak saw us S ee Saw ust d t . d . L n en . on as in C e C ee m n n i gr , W , g rippl r k i i g Os o n mm e 0 . O . e o en a on for s an b r , , r c d ti t d district . . ard ofven a on 1 6 Lo e M C o e a am in a en s til ti dg ill lli ry, bl ck d p , ccid t Ov z . K . on a so on ofox en coa 21 1 1 —1 2 it , F , b rpti yg by l Ox a on ofair in oa m nes 77 id ti , c l i M in m e a m nes 77 . t l i Ox a on of oa ex e men s on id ti c l , p ri t Ma l e M P . . on a so on of ox en h r , b rpti yg by a e of 20 21 r t , oa c l Ox en a bso n of m f o oa a oun o . 79 yg , rpti , by c l , t Ma McK inn m n a in ff f ey e, ir e e o W n ry i , ct i d m o e of 1 9 21 d , and em a u e ou 59 t per t r . . power of 6 as in ana ses of 56-5758 60 g , ly , utilization of 1 9 sam n of 58 pli g a so on of oa us 21 b rpti , by c l d t s in effe of ox en n n n , o e o . 62 light ct yg c t t onsum on of s in m nes 25 c pti , by light i o a on of 58 ‘ l c ti e ease of eflect on s 28 3 0 61 62 80 , g , , , , Me a m nes air in ana e of — d cr li ht , , s s . 63 78 t l i ly effe t of on ea in 9 1 0 —1 4 61 78—79 c , br th g , 9 a am in ave a e om os on of 81 bl ckd p , r g c p iti . on combustion 80 e en a e of 66—76 77—78 81 p rc t g , , esu n in m o e n o en 80 as n in e r lti g r itr g , e on air in 76 77 bl ti g ff ct , ef e o f su o na e in ven a on s s f ct , b rdi t d til ti y carbon dioxide given off in 26 tems oxidation ofair in 77 in air at a n a f se eve , e e e o ox en in onsum on of l l p rc t g yg , c pti 26 in a am e en a e o f bl ck d p , p rc t g Me ane effe of on ox en on en ofm ne th , ct , yg c t t i in ea n ans e of br thi g , tr f r . D in oa m n En law n es , s o ex os of effe of a ofox en n c l i gli h pl ibility , ct l ck yg o reduction of lim its of in a m x u es e en a e o f g s , in oa m ne m i t r p rc t g s an e o . c l i , d g r fr . in m ne air effe o f on fire i , ct , prop ortion of factors decreas ing in ex os ve m x u es o o t on of pl i i t r , pr p r i , percentage of 50 effect of essu es of o es on n to arome inflammabilit f pr r , c rr p di g b tric y o essu es Me ane-air mix u es ex os bi pr r of efiect th t r , p l i lity , ee a so S l Fire damp . ofblack damp on P ef e t ofox en on ent o . f c yg c t n. ex e men s on Penns vania an a e oa m ne in anal p ri t yl , thr cit c l i , y s om e u on f ri k fr , r d cti o ses o fair in inflamm abilit f m - o s of. uminou s m ne law o f y , li it bit i S ee also C a on oxi e. um nous m nes in ven l a on in rb di d bit i i , ti ti Me ane ame ef e t ofex n u s in atmos Pe o S i flame e e o f ex in u s in th fl , f c ti g i h g tr l p rit , ff ct t g i h g ph eres on atmospheres on - Me a e s t ame e e of ex n u s Pet o eum am e effe t o f ex n u s in thyl t d piri fl , ff ct ti g i h r l fl , c ti g i h g in atmos e es on n g ph r atmospheres o . . 88 I N DE" .

Pa e g . H n f ox en T m Po e . C . on a so o o e m ne e a of ef e t o f on air rt r , b rpti yg by i b r , i , d c y , f c coa l decrease o foxygen content by n eas e f a n d on ox idation o f coal . i cr o c rbo io xide by G on e e o f a on ox e on sou e o f a am P es . . 26 ri tly , J , ff ct c rb di id rc bl ck d p n a m ines anal fair in — ea n 8 To o h ses o . 64 75 br thi g p , y

P o a a on of am e m o an e of 23 T o an S . D ak . m nes at ana ses o f air in 69 r p g ti fl , i p rt c r j , , i , ly

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