CHAPTER 6 GEOLOGY Canyon Fuel Company, LLC Mining and Reclamation Plan SCM/Dugout Canyon Mine May 1998

Home , Point Lookout Sandstone

TABLE OF CONTENTS

Section

610 INTRODUCTION 6-1

611 General Requirements ...... 6-1

61 2 Certification ...... 6-1

620 ENVIRONMENTAL DESCRIPTION ...... 6-1

624 General Requirements ...... 6-1

622 Cross Sections, Maps and Plans...... 6-2

623 Geologic Determinations ...... 6-4

624 Geologic Information...... 6-4

624.100 Regional Setting ...... 6-4

Stratigraphy ...... 6-5 Mancos Shale ...... 6-5 Mesaverde Group ...... 6-5 • Star Point Sandstone ...... 6-7 Blackhawk Formation ...... 6-8 Castlegate Sandstone ...... 6-9 Price River Formation ...... 6-10 North Horn Formation ...... 6-11 Flagstaff Formation ...... 6-12 Colton Formation ...... 6-12 Quaternary Pediment Gravels and Alluvium ...... 6-13 Structure ...... 6-13 Surface and Groundwater Impact...... 6-14 Coal Geology ...... 6-15 Cross-Sections, Maps, and Plans ...... 6-16 Drill Logs and Chemical Analyses ...... , ...... 6-16

624.200 Test Boring and Drill Hole Data (overburden removed) ... 6- 1 6

624.300 Test Boring and Drill Hole Data (overburden not removed) 6-16

Lithologic Logs ...... :" .-:- . . . .. 6-16 ,; ,7 '" Acid, Toxic, and Alkaline Chemical Analyses ( bd~ ~nQ ' .J~~; below the coal seam) , , , , , , , , , , , , , , , , , , , , , , ',-'fV17 ,cf(0 '

r ..) j ~ ". " \, 6-ii

I' Canyon Fuel Company, LLC Mining and Reclamation Plan • SCM/Dugout Canyon Mine May 1998 TABLE OF CONTENTS (Continued)

Section

Acid, Toxic, and Alkaline Chemical Analyses (coal seam) ..... 6-17 Roof and Floor Rock Clay Content ...... 6-1 7 Ground Water Occurrence ...... 6-1 7

625 Additional Geologic Information ...... 6-18

626 Sampling Waivers ...... 6-18

627 Description of the Overburden Thickness and Lithology 6-18

630 OPERATION PLAN ...... 6-18

631 Casing and Sealing of Exploration Holes 6-18

632 Subsidence Monitoring 6-18

640 PERFORMANCE STANDARDS 6-19

641 Exploration and Drill Holes 6-19

642 Monuments and Surface Markers of Subsidence • Monitoring Points ...... 6-19 REFERENCES ...... 6-20

, ..~.

.----"~ ~ l .. --"'- 6-iii Canyon Fuel Company, LLC Mining and Reclamation Plan • SCM/Dugout Canyon Mine May 1998 LIST OF FIGURES

Figure

6-1 Dugout Canyon Mine Geologic Cross Section A - A' 6-3

6-2 Stratigraphic Section Dugout Canyon Area ...... 6-6

LIST OF PLATES

6-1 Geology of the Dugout Canyon Mine Permit Area

6-2 Coal Seams Dugout Canyon Mine Portal Area

6-3 Geologic Cross Sections 8 - 8' and C - C'

6-3A Geologic Cross Sections 0 - 0'

6-38 Geologic Cross Sections E - E' and F - F' • 6-4 Rock Canyon Seam - Overburden Thickness 6-5 Rock Canyon/Gilson Seam Interburden Map

6-6 Rock Canyon Seam Isopach Map (Confidential Folder)

6-7 Gilson Seam Isopach Map (Confidential Folder)

LIST OF APPENDICES

Appendix

6-1 Drill Hole Logs (Confidential Folder)

6-2 Rock Canyon Coal Seam Roof and Floor Rock Chemical Analyses (Confidential Folder)

• 6-iv Canyon Fuel Company, LLC Mining and Reclamation Plan SCMIDugout Canyon Mine March 1998

CHAPTER 6 GEOLOGY

610 INTRODUCTION

This chapter presents a description of the geologic resources in the area of the Dugout Canyon Mine. Most of this chapter has been compiled from the approved Geology section of the Sage Point-Dugout Canyon Mining and Reclamation Plan , formerly designated by the State as ACT/007/009.

611 General Requirements

The geologic resources in the Dugout Canyon Mine area through 627 of this chapter. The plans for casing and seali subsidence monitoring are addressed in Section 630 through

612 Certification

All maps, plans, and cross-sections presented in this chapter, required by the regulations, have been certified by a professional engineer.

620 ENVIRONMENTAL DESCRIPTION

This section presents a description of the geologic resources in the area of the Dugout Canyon Mine.

621 General Requirements

This section presents the regional and site-specific geologic information for the Dugout Canyon Mine area.

6-1 Canyon Fuel Company, LLC Mining and Reclamation Plan SCM/Dugout Canyon Mine May 1998

622 Cross Sections, Maps and Plans

Plate 6-1 presents the surficial geology of the permit area, the Rock Canyon coal seam outcrop line, the strike and dip of the coal seam mined, and the locations of the drill holes in the mine area. The outcrop lines of the Rock Canyon and Gilson coal seams within the Dugout Canyon Mine disturbed area are illustrated on Plate 6-2. A north to south cross section, labeled as A to A' on Plate 6-1, is illustrated on Figure 6-1. This cross section displays the relative thicknesses of the formations and the stratigraphic position of the Rock Canyon coal seam. The location offour additional cross sections, labeled as B to B', C to C', D to D', E to E', and F to F', are identified on Plate 6-1. Cross sections B to B' and C to C' are illustrated on Plate 6-3, D to D' on Plate 6-3A, and E to E' and F to F' on Plate 6-3B. These cross sections demonstrate the relative position and thicknesses of the Rock Canyon, Sunnyside, and Gilson coal seams in the permit area. Cross sections also illustrate the stratigraphic locations of rider seams associated with the Rock Canyon and Gilson coal seams . The geologic map and six cross sections are based upon drill hole_ data and on the work previously performed by Anderson (1983) and lntrasearch (1998).

The overburden associated with the Rock Canyon coal seam is il lustrated on Plate 6-4. The interburden thickness between the Rock Canyon and Gilson coal seams is presented on Plate 6-5. The thicknesses of the Rock Canyon and Gilson seams in the permit area are illustrated on Plates 6-6 and 6-7, respectively. Since the Sunnyside seam is not of mineable thickness in the permit area, coal isopach, interburden thickness, and overburden maps are not presented for this seam in this permit.

The geologic logs from the following coal exploration drill holes have been included as Appendix 6-1 as a supplement to the geologic maps and cross sections. Although other drill holes occur within the permit area, the drill logs provided characterize well the stratigraphy oT the permit area.

• 3-1 • 9-1 • 9-2 • 10-1 • 11-1

6-2 GEOXSEC.DWa UC485-OI 3-05-11

NORTH SOUTH A' A Io Roan Cliffs I I ('II Book Cliffs - IN ::c~ 9000 - 9000

8000 8000

7000 7000 ~ Dugout Creek > \ "*==< T~ ,. Qat Qg

6000 6000

Mancos Shale

5000 5000

---- SECllON TURNS

4000 I }' '; , 4000--- From And"~n~~ t~,;~" i!"'""-._ _.. ""'. : lit, 1000' OC T 1 6 ' 199;-1~, ! L~~~'"' - :;...,.::...... ~ ..... '-"""~~...... ~-~ UP4h j "'c. ~,-, ~ "L;.. ,: \\. f: 0' • ~<., '~", ~~-"'~'~"''''''''''' 2000' ...... "'-'-.-~!.-,.:., •. ,.... ~..-~;.;;.:J SCALE ...... r•...... • L.'-#J...... --- FIGURE 6-1. DUGOUT CANYON MINE GEOLOGIC CROSS SECTION A-A' EarthFax

6-3 Canyon Fuel Company, LLC Mining and Reclamation Plan SCM/Dugout Canyon Mine September 2006

• 13-1 • 13-2 • 13-3C • 14-1 • 14-4 • 14-5 • 15-1 • 15-2 • 15-3 • 19-2 • 24-1 • 24-2 • 24-3C • 24-4C • HCC-4 • KCC-A • KCC-E • MDC-1A • N-13 • N-14 • N-15 • N-18 • N-19 • • N-20 No oil or gas wells are known to exist within the permit area. However, degassification wells have been drilled for releasing gas from the underground mine workings. Refer to the Degassification amendment for additional information.

623 Geologic Determinations

The information required by the Division to make a determination of the acid or toxic forming characteristics of the site strata is presented in Section 624.300 of this M&RP.

The information required by the Division to make a determination as to whether the reclamation plan, described in Section 540, can be accomplished is presented in Section 624.

The information required to prepare the subsidence control program is addressed in Section 624.

6-4 co PO T SEP 1 3 2006

Div. of 0" G Canyon Fuel Company, LLC Mining and Reclamation Plan SCM/Dugout Canyon Mine March 1998

Stratigraphy. All rock units within the Dugout Canyon Mine permit area are sedimentary (Plate 6-1 and Figure 6-2). No igneous or metamorphic units have been found in the area. The exposed, consolidated sedimentary rocks in the area were deposited during the Cretaceous

Age of the Mesozoic Era and the lower Tertiary Subera . The on -es unit ' ~ We.,--__ , -- .. _-- Cretaceous Mancos Shale, which is overlain in order of increasingl ., yd~ger.A a'c~s, 1 by the Star 'J- , if"' . l,. J J' Point Sandstone, the Blackhawk Formation, the Castlegate andstor).a,_t~"e ,J \ ;r E¥ River Formation, the North Horn Formation, the Flagstaff Formation and th

(Figure 6-2). I I I Mancos Shale. The Mancos Shale has been mapped througho t e Hi'v U ~ah an,d JW~ltg~ lMNG I Colorado and is the lowest rock unit exposed in the southern h ea. This formation is best exposed at the base of the steep Book Cliffs where overlying pediment gravels have been eroded or in the flat valley bottoms where streams have eroded through the alluvial cover. The Mancos Shale consists of bluish-gray fissile claystone or mudstone which weathers light bluish-gray to light tan. The formation contains thin calcareous sandstone and siltstone interbeds which upwardly increase in frequency. The interbeds of sandstone and siltstone are usually dark gray to light tan to yellow. The formation forms steep, barren, easily eroded slopes with occasional ledges of more resistant fine-grained sandstone, siltstone, or sandy claystone. The formation supports little to no vegetation. The Mancos Shale is between 4,700 and 5050 feet thick in the Book Cliffs Region (Clark, 1928). However, only approximately 200 feet of the upper Mancos Shale is exposed within the permit boundary.

Mesaverde Group. The name "Mesaverde Group" (Holmes, 1877) was originally used in southwestern Colorado to describe a sequence of marine sandstone and shale with non-marine coal-bearing rocks interbedded between marine rocks. The name has since been used in the Book Cliffs from Utah to Colorado and includes intertonguing marine and non-marine rocks. The Mesaverde Group in the permit area lies on and intertongues with the Mancos Shale, making the uppermost Mancos to the east time equivalent with the thinning Mesaverde marine sandstone to the west. From base to top, the group contains the following formations:

6-5 SlRAT.DWG UC485-06 3-11-96

SYSTD.4 SERIES SlRA'IlCRAPHIC UNIT LITHOLOGY THICKNESS DESCRIPTION

RED SHALE WITH SOME GRAY-GREEN SHALE. INTERBEDDED Z o LIGHT GRAY TO GREEN COARSE TO FINE GRAINED ~ LENTICULAR SANDSTONE . BASAL GRIT AND PEBBLE w « CONGLOMERA TE IN SANDSTONES. Z ~ W 0:: U o o --:::-:::-:::~ w LL oZ I FORMS THE ROAN CLIFFS . o-.J U

:::-:::-:::~. ~. 0::: --- - wZ INTERBEDDED GRAY-GREEN TO RED VARIEGATED SHALE. >0 ------LIGHT GRAY TO GREEN MEDIUM GRAINED LEN TICULAR w ~t= « ~~ SANDSTONE AND THIN BEDS OF FRESHWATER LIMESTONE . Z FORMS RESISTANT DIP SLOPE. w Z~ ~ ------U wa::: o wo r_-_-_-_I- W a:::u.. -- -f-_-_ -.J c..? « -~~~' __~~h~.~~_~. ~ -L __. a.. .~) <- ~ "=- z UJI J (: \ lr ) 1 ))~() ]0 "]Fi ~ . ... " a::: Z INTERBEDDED GRAY. GRA Y- ' ~ RE,£ Kf.\j PtJR E: H:[,' :1I". ) [ , J" \ J F1 J)) I 00 YELLOW- TAN CALCAREOUS HALE. LIGHT . -' ~E e ' ~J:: AM II- MARL WITH SMALL LlMESTO~ E NODUL ~ S;--AND LlGH .~~. « o COARSE TO FINE GRAINED L :::NTICULA CHANNEL . DANIAN I~ N I-a::: (0 SANDSTONE UP TO 40 FEE IN THICKN oor 16 199(; 0:::0 Ou.. Z Z « I l- UPPER SANDSTONE-GRAY 0 IMOOU A'f, fI,{;j- 'MN , I I t':IOO ~Pi A' SANDSTONE, WITH THIN BE[ S OF SILTSTONE, SHALE AND f U a::: CARBONACEOUS SHALE. CLlFF~FOt'ffirE -·----i...... _ -d,_ . I MIDDLE PORTION-LIGHT GRAY TO TAN MEDIUM TO FINE (f) GRAIN SANDSTONE INTERBEDDED WITH SHALE AND SILTY W « SHALE. ~ ' .. ~ ~<. ' . 2>~ GRAY, MEDIUM GRAINED SANDSTONE, WITH SOME THIN 7 ;' ,:;:, ~ : ' ::: ':: L:~ " :;j.': LENSES OF CARBONACEOUS SHALE . CLIFF FORMER. y .':':;' j ';' .. <:> 1i:. ,':":\7. .-;; .. o:"~: en -1 Z a.. 8~ ;~~/ti~ ::J ::l z CD ------o o o W a::: i= -i--+~-~.·"'y~{ COAL BEAR ING-INTERBEDDED LIGHT GRAY. MEDIUM TO U o « FINE GRAINED SANDSTONE. SILTSTONE. GRAY TO w ~ z ------CARBONACEOUS SHALE AND COAL. < o a::: ~ -~-=-~-:-=- J- a::: o LOWER PORTION-GRAY LITTORAL. MEDIUM TO VERY FINE W w u.. GRAINED BIOTURBATED SANDSTONE AND SANDY 0::: > co SILTSTONE WITH TONGUES OF MANCOS SHALE IN z « ~ V U « (f) ~ BETWEEN THE MAJOR LITTORAL TONGUES (THICKNESS OF Z w « TONGUES NOT TO SCALE). « ~ I ; ~ ~~~I~~~~~~ ~ a.. U ~ « « -.J u m

~ ~ ~ ~:~~~~t~ g: ~~~~ESA~~~/~L~~l~NSE 6?~~~E~T~R~EA~~AY =--= (f) a... " -:;'-::-:;:-:''7~~-\' N PANTHER TONGUES. NON-RESISTANT. r~~ MASUK TONGUE ------GRAY TO DARK GRAY. MARINE SHALE, 'r ",' - MANCOS SHALE:::::: CALCAREOUS AND GYPSIFEROUS SLOPE FORMER. l '-I'J _ ...... -~ FIGURE 6-2. STRATIGRAPHIC SECTION DUGOUT CANYON AREA EarthFax AFTER ANDERSON, 1980 6-6 Canyon Fuel Company, LLC Mining and Reclamation Plan SCM/Dugout Canyon Mine March 1998

• Star Point Sandstone, • Blackhawk Formation, • Castlegate Sandstone, and • Price River Formation.

Star Point Sandstone. Exposures of the Star Point Sandstone, the basal member of the

Blackhawk Formation, form a broad, arcuate band crossing east r ~~ - tar-pad ~ tendin-g Into I '.~(\ (( \1 f- J ]D.l(1J1T' A 17":lJD eastern Wyoming, where it is roughly correlative to the Shannon S n -si o'ne of-A !t~ Coe.' I Shale', .'t.J ~ . >.Jl"f.iE 'T V -:. and into southwestern Colorado and northeastern New Mexico where 11: --e-qUiva en - ~€ Point Lookout Sandstone (McGookey, D.P., 1973).

The formation reaches thicknesses of more than 1 ,000 feet in th Pleasant Valley area in t e . . UTAH I ':iIO rr Q-,u, d northern part of the Wasatch Plateau. The formation thins s ~uthwar along t ne vva 81t l'-i N J - -.-- Plateau and eastward in the Book Cliffs, and the lowermost units of the Star Point -graee ir:lt o,-_ the underlying Mancos Shale (Spieker, 1931). Marley (et. a!. , 1979) state that the Star Point Sandstone is a coastal complex of distributary channel, delta front, and beach barrier sediments.

Approximately 230 feet of Star Point Sandstone is exposed in the permit area between Soldier Creek Canyon and Fish Creek Canyon. However, the formation apparently pinches-out within the Mancos Shale east of Fish Creek Canyon (Anderson, 1983). The exposures in Fish Creek Canyon are generally recognized as the easternmost exposures of the formation (Young, 1955, p. 184; Balsley 1976). The Star Point Sandstone is a gray to grayish tan, very fine to fine-grained, calcareous sandstone with gray to dark gray siltstone and mudstone. The formation is thin to medium bedded. The upper sandy unit contains concretionary, sandy structures that are better cemented than the enclosing rock. In the permit area, the formation generally forms slopes with ledges of moderately-resistant sandstones.

The base of the Star Point Sandstone is arbitrarily drawn where the regular, thinly interbedded siltstone, sandstone, and "Mancos-like" mudstone changes or grades into non-resistant mudstone (after Folk, 1968, p. 28). This contact is difficult to trace along the cliffs and has

6-7 Canyon Fuel Company, LLC Mining and Reclamation Plan SCM/Dugout Canyon Mine March 1998

been mapped as inferred. The upper contact with the overlying Blackhawk Formation is drawn at the first appearance of moderately well cemented, interbedded sandy siltstone that overlies a thick, 65 to 122 feet thick sequence of "Mancos-like" mudstone (Balsley, 1976).

Blackhawk Formation. The Blackhawk Formation crops out from Thousand Lakes Mountain

in south central Utah, along the Wasatch Plateau northward to the ~o · o 1 ~~~~~~_ along the Book Cliffs to a few miles east of Thompson, Utah ' i ~ ~Pf~r;n )~RL~ ((lsl irt:i'me ~r~f 10) , correlatable with the lower Wahweap Formation of southern Utah ( eterson 1 f'I""" 1B2- 183) and the upper Mancos Shale of western Colorado (Fisher, 1 60).

The formation is well exposed in the cliffs and canyons of the per' it area.

top, the Blackhawk Formation contains the Spring Canyon, Aben e " Ke l'il ilw~rt ~( ern ,

lower and upper Sunnyside Members. The Aberdeen and Kenilw ~ cliff-formers of the Blackhawk in the Dugout Canyon area. The Blackhawk has been found in the subsurface in all the drill holes located north of the outcrop and is present in the • subsurface throughout much of the Uinta Basin to the north (Anderson, 1983). The thickness of the Blackhawk Formation ranges from over 1440 feet to the west of the permit area in the Deadman Canyon area (Nethercott, 1985) to about 910 feet to the east near Pace Creek (Anderson, 1983). The formation thins easterly as the Spring Canyon Member pinches out. Subsurface information on the entire thickness of the Blackhawk Formation is lacking since most of the drilling was performed as part of coal exploration and the coal lies near the middle of the formation.

The aforementioned members of the Blackhawk Formation are a series of upward coarsening littoral sequences, each related to an episode of marine regression. The Kenilworth Member is a complete representation of the littoral lithologies and is described herein. The base of the member is a slightly silty mudstone, gray to dark gray, slightly calcareous and carbonaceous, and generally massive bedded and non-resistant. Above this is an intensely bioturbated unit consisting principally of sandy siltstone to very fine-grained thin sandstone beds with interbeds of mudstone. Overlying this transition unit is fine-grained, yellow-gray sandstone, which is

6-8 Canyon Fuel Company, LLC Mining and Reclamation Plan SCM/Dugout Canyon Mine March 1998

hummocky cross-stratified (Harms, 1975, p. 87), thick- to massive-bedded, resistant, and bioturbated. Overlying this unit is a fine- to medium-grained, yellow-gray sandstone with ~ - - .. ~-.~ .~.------~ trough cross-stratification, mildly bioturbated, and resistant. The uppermos:\ un,iJ ~ J f ~ 1~ (~tD fra' sequence is a fine-grained, horizontally bedded, resistant sandstone that Y u ~ '9.;. 5) referred to as the "white cap". On fresh surfaces, this sandstone is Jsually lig (gray"" to--.::J"!~- gray. This upper unit of the littoral sequence may not always be pr ~ sent in II esn of the formation.

JTAH n, I,)ION Ou, GA:'> .l\ND MI"1ING The coal bearing rocks in the permit area are generally found above the Kenilworth Memger "' ...... ,,~ and intertongue with and overlie the Sunnyside Members. These units consist of tan to gray, fine-grained, occasionally cross-bedded and ripple marked sandstone, tan to gray siltstone, brown to gray mudstone, and black to dark brown carbonaceous mudstone. All these beds contain variable amounts of carbonaceous material, rare beds of well preserved plant fossils, and fresh- to brackish-water mollusks. As a group, the coal-bearing rocks are moderately resistant. Lenticular coals are present throughout this section of the Blackhawk Formation, and several beds are of mineable thickness. The characteristics of the coal seams are discussed further in this chapter under the subheading of Coal Geology.

The contact between the Blackhawk Formation and the overlying Castlegate Sandstone has been recognized by Spieker (1931), Clark (1928), and Young (1955) as an angular unconformity in the eastern Book Cliffs and Wasatch Plateau area. Anderson (1983) described the contact in the permit area as apparently conformable, but thickness variations within the area may indicate a discontinuity. In the subsurface, the contact is sometimes identifiable by the first occurrence of the thick carbonaceous mudstone of the Blackhawk Formation.

Castlegate Sandstone. The Castlegate Sandstone extends across the entire length of the Wasatch Plateau and the Book Cliffs (Spieker, 1931) but loses its character as a cliff-former south of the Interstate Highway 70. The formation is believed to have been deposited in a braided stream environment. It is correlative to the Cliffhouse Sandstone of southwestern Colorado and northern New Mexico (McGookey, 1973). In the Wasatch Plateau, its thickness

6-9 Canyon Fuel Company, LLC Mining and Reclamation Plan SCM/Dugout Canyon Mine March 1998

ranges from 50 to 500 feet (Spieker, 1 931 ). In the permit area, the Castlegate Sandstone is between 161 and 286 feet thick (Anderson, 1983).

The Castlegate Sandstone is a fine- to medium- grained Quartz sandstone that is very light gray on fresh surfaces and weathers light tannish-brown. The unit is cemented with clay and calcium carbonate and has moderate porosity. Sorting is poor, and rounding ranges from subangular to subrounded. The sandstone contains trough, planar, and some tabular cross bedding, current ripples, convolute bedding, and small scale graded beds 0.5 to 2.0 inches thick. Locally, thin lenticular beds of siltstone and mudstone occur and contain abundant carbonaceous plant material. These finer grained units are most common in the upper and lower sections of the formation. The formation typically forms ledges and cliffs in the permit area.

The upper contact with the overlying Price River Formation is laced ~ a ! t'he l[h> n~a (k )) f1l ) :lope if~;r) where the sandstone becomes finer grained and interbedded w th mudstone l'a 'm '(~L ·I vst.one. • The contact is sometimes difficult to map on the surface but is di tinctive in eophysical logl from area drill holes. T 6 1998 0 1 I I

Price River Formation. The Price River Formation is the uppermos m9frubep,ot- rt ti'l:e)M. .~s II group and is found in continuous outcrop along the Book Cliffs_-nJ"L~~~Qf-.,.~U~!.!.!..~~~~=--_· formation are moderately resistant slope formers while the upper units are typically resistant cliffs formers. The thickness of the formation in the permit area ranges from 327 feet to 489 feet.

The lower slope-forming units of the formation consist of mudstone and siltstone with some fine-grained sandstone and carbonaceous mudstone. These units are dark gray to tan, lenticular, and grade into one another. The upper units of the formation are light gray to very light gray, thick to massively bedded sandstone. The medium- to fine-grained, subrounded to subangular, moderately well cemented Quartz sandstone is friable and porous at the base and is upward fining. Some beds contain disseminated carbonaceous material, cast of tree stems and trunks, and minor bioturbation. The sandstone shows horizontal stratification, ripple

6-10 Canyon Fuel Company, LLC Mining and Reclamation Plan SCM/Dugout Canyon Mine March 1998

marks, and trough cross-bedding. The thick and massive sandstone is broken by beds of gray to dark gray mudstone and siltstone that are less resistant. These uppermost sandstone beds normally appear on outcrop as three cliff-forming units, each separated by a thin slope forming unit, but occasionally they join to form a single massive cliff. The contact with the overlying Cretaceous - Tertiary North Horn Formation in the permit area has been picked as the top of the uppermost, latera"y consistent, cliff-forming sandstone (Anderson, 1983).

North Horn Formation. The North Horn Formation is Cretaceous-Tertiary in age and conformably overlies the Price River Formation. It is moderately resistant and forms a steep slope with occasional sandstone ledges. The contact with the overlying Flagstaff Formation is difficult to determine. Therefore, thicknesses determined from measured sections, both on the surface and in the subsurface, vary by several hundred feet. Anderson (1983) determined that the formation ranges from 620 feet near Fish Creek to 1 330 feet in the subsurface in the Minnie Maud Creek area .

J The North Horn Formation was deposited in flood plaint a ~ cf lacust ~ i.n~ ) l€"'n ~~ rC?{lm l~ rylt~J Sandstone beds near the base of the formation are similar to tHe sandston s ~ 0·t~ f1a Fin.ce River Formation but are finer-grained and thin- to medium-beddled. Th i~wer secti ~ 0 the formation is comprised mainly of interbedded gray to light gra sandstl nQ h d1 a grayish green calcareous mudstone. The sandstone units are fluvial in jl Origin, lenttcu1-a., art reEtuently conglomeratic at the base with a fining upward trend. (h, • , )~ n r lA:) AND MI~r G

The upper part of the formation consists mainly of yellowish tan to gray marlstone with numerous sma" limestone nodules and gray, grayish green, yellowish tan and purple calcareous mudstone. In Soldier Creek Canyon, a local, thin coal bed is present in the upper North Horn Formation.

The contact with the overlying Flagstaff Formation is typically drawn at the base of the first relatively pure, fossiliferous, thin limestone beds. The limestone beds are generally consistent across the permit area, but occasionally the limestone grades into marlstone, thus making determination of the contact difficult. The limestone beds are underlain and overlain by slope

6- 1 1 Canyon Fuel Company, LLC M ining and Reclamation Plan SCM/Dugout Canyon Mine March 1998

forming mudstones. Since the limestone beds are typically fractured, they also form slopes, further complicating the task of determining the upper contact of the North Horn Formation.

Flagstaff Formation. The Tertiary age Flagstaff Formation is found throughout the Wasatch Plateau and above much of the Book Cliffs. It is contemporaneous with the Claron and Wasatch Formations of southern and south-central Utah. In the permit area, this formation forms a gentle dip slope on top of the Book Cliffs. Anderson (1983) determined the thickness of the formation in this area to be between 265 and 470 feet. The Flagstaff also thins from west to east across the permit area.

The Flagstaff Formation is an interbedded sequence of sandstone, mudstone, marlstone, -and limestone. The sandstone is fluvial in origin, lenticular, calcareous, medium to fine grained, tan to brown in outcrop and gray to grayish green on a fresh surface. The mudstone is dominantly grayish green and calcareous w ith some re , '3ri e @B ~ ~-Q.ue §. r the...... top. of the formation. The lime~tone beds are thin, typi all .~ jless ~ ha Jh ~ p 't4 r I' ~~ ~~ t ryli9 J[)Th ~ limestone is generally fossiliferous, containing fresh ater gastropp ':r ~ e~cypods, an ostracods.

The Flagstaff forms a moderate slope at the top of th Book limestone and calcareous sandstone protecting and o illl, t ~ , r ,~tJ ea ,t .f t Qe cliffs. T e fi, AS 1""\ Nt MINING upper contact of the Flagstaff Formation with the Colt OrllTatfoA is dfaw at tba..,top 0 a sequence of thin bedded, greenish gray sandstone beds. This contact is well marked in the permit area by the break in slope at the base of the Roan Cliffs.

Colton Formation. The Tertiary Colton Formation crops out in the northeast corner of the permit area but a full thickness of the formation is not present; only about 850 feet of the Colton Formation is exposed in the permit area . The lower units of this formation forms the Roan Cliffs which stretch from the Price River Canyon area to beyond the Colorado-Utah Border. The Colton Formation was formerly called the Wasatch Formation in eastern Utah.

6-12 Canyon Fuel Company, LLC Mining and Reclamation Plan SCM/Dugout Canyon Mine March 1998

The formation consists of grayish green, tan to light reddish brown, mostly fine grained, calcareous sandstone with occasional basal beds of thin clay and marlstone clast conglomerates and interbeds of mudstone or siltstone. The sandstone is generally lenticular and resistant and appears to be of fluvial origin. In the lower portion of the formation, the mudstone and siltstone predominate over the sandstone. The mudstone is mostly dark reddish brown with some variegated gray, green and yellow colors. The mudstone is usually calcareous and non-resistant, frequently grading into siltstone.

Quaternary Pediment Gravels and Alluvium. Pediments with gravel veneers are especially well developed below the Book Cliffs escarpment. They occur east to west across the southern portion of the permit area. As the more resistant rocks of the cliffs retreat by physical and chemical weathering, the softer and more erodible Mancos Shale is covered by thin layers of unconsolidated materials from the retreating cliffs. The deposits gradually thin away from the cliff face. The pediment deposits are partially cemented with .<:.alcium carbonate, poorly stratified and sorted, of local origin, and range in size from large ba 19r rs -t o cla-y size--par -IC e-s. ~ 1 , It ~ I ,I J 1L Jl I I 1 . -' JJ. - • .. l' L l:F 'E( c, I " The alluvium in the permit area consists of poorly stratified cays, siltls, sands, ang ' me gravels. Younger than the pediment gravels, it is distributed m inly belo the drainages between the pediments.

Structure. The permit area lies between the Mancos Lowland a d t ~k ' Bo~k ~ 'e If s-Roarr 6 lifi'Ts INn j Plateau (Stokes, 1977). The San Raphael Swell and the Farnum antic me structure of the area. Both structural features are located south of the mine area.

The regional structure of the Book Cliffs from Price to Green River curves around the plunge of the San Rafael Swell (Doelling, 1972, page 264, Figure 9). The strike of the beds in the permit area changes from N 82° W on the west side to N 62° W on the east side, approximately following the Book Cliffs Escarpment. The dip is north to northeast averaging about 8 degrees but has a range of 6.2 to 11.5 degrees. The Farnum anticline lies about seven miles south of the permit area and has a strike of approximately N 30° E and plunges to the north.

6-13 Canyon Fuel Company, LLC Mining and Reclamation Plan • SCM/Dugout Canyon Mine May 1998 about 8 degrees but has a range of 6.2 to 11.5 degrees. The Farnum anticline lies about seven miles south of the permit area and has a strike of approximately N 30° E and plunges to the north.

Faulting in the permit and adjacent areas is minor. Anderson (1983) mapped a small east-west trending normal fault, with a few feet of displacement down to the north, at the center of the eastern border of Section 20 and the center of the western border of Section 21, Township 1 3 South, Range 1 2 East (Plate 6-1). The stri ke of the fault, N 83° W, is parallel to the regional st-rike of the dominant bedrock fracture system. Anderson (1983) supposed that the fault was probably related to the slumping or breaking away of the rock from the Book Cliffs escarpment.

A second normal fault in the permit area was mapped by Clark (1928) and confirmed by Anderson (1983) and is located the northeast quarter of Section 12, Township 13 South, Range 12 East and through the northeast quarter of Section 18, Township 13 South, Range 13 East. This fault trends northwest-southeast and has a displacement of approximately 25 • feet down to the southwest.

Numerous small faults are present along the coal outcrop and appear to be related to the burning of the coal. Field investigations suggest that this faulting is surficial and does not extend past the burned coal at depth.

Jointing in the bedrock roughly parallels the local structure and is the result of San Rafael upwarping. Anderson (1983) mapped several near vertical joints in the perm it area that trend to the west and northwest. The joint patterns are well displayed in the outcrops in the Book and Roan Cliffs and Pine Canyon.

Surface and Groundwater Impact. Surface and groundwater impacts are discussed in Chapter 7 of this M&RP. .--

6-14 Canyon Fuel Company, LLC Mining and Reclamation Plan SCM/Dugout Canyon Mine May 1998

Coal Geology. Anderson (1983) identified the following five coal seams within the permit area:

(Bottom to Top) • Kenilworth, • Gilson, • Fish Creek, • Rock Canyon, and • Sunnyside.

According to Anderson (1983)' the coal beds are lenticular and sometimes difficult to correlate between drill holes. However, the five seams listed above do show some lateral continuity in the permit area and can be identified as individual coal beds. Only the Gilson and Rock Canyon coal seams appear to be sufficiently developed in the permit area to allow for economic mining under current conditions .

The Rock Canyon and Gilson coal seams will be mined at the Dugout Canyon Mine under this • permit. A northwest-southeast trending want area in the Rock Canyon coal seam is present in the north-central portion of the permit area (Plate 6-3). In the want area, the coal thins to less than 3 feet and contains several splits. Outside the want area, the coal ranges between 5 and 8 feet thick. In the areas where the Rock Canyon seam is of mineable thickness, the interburden between the Gilson and Rock Canyon seams ranges from less than 30 to more than 80 (Plate 6-5).

The as-mined quality of the Rock Canyon coal seam west of Dugout Canyon is projected to

average 12,000 + BTU, 10.3 % ash, and 0.65 % sulfur. The coal is ranked as a bituminous high volatile B.

East of Dugout Canyon, sulfur content in the Rock Canyon coal seam increases to greater than

1.00/0 thus rendering coal from this seam unsaieable and unprofitable to mine at this ti ~ e. Additionally, the interburden thickness between the Rock Canyo and Gilson seams generally '\) r . . c{"y \ . 6-15 \ _-.l • . ------Canyon Fuel Company, LLC Mining and Reclamation Plan SCM/Dugout Canyon Mine May 1998

diminishes to the east of Dugout Canyon and near the center of the federal lease coal making multiple seam mining difficult, dangerous, and uneconomical (Plate 6-5).

The as-mined quality from the Gilson coal seam in the area of Dugout Canyon Mine and to the

east of the canyon is expected to average 12,250 BTU, 10.4% ash, and 0.55 % sulfur. This coal is also ranked as a bituminous high volatile B. The Gilson seam is of mineable thickness in limited areas west of Dugout Canyon, therefore, the majority of the mining in this seam will occur east of the canyon in the federal lease area. Multiple seam mining will occur in a relatively limited portion of the permit area, generally in the vicinity of Dugout Canyon.

Cross-Sections, Maps and Plans. The cross-sections and maps are discussed in Section 624 and are located at the end of this chapter.

Drill Logs and Chemical Analyses. See Section 624.300 and Appendices 6-1 and 6-2. The • applicant requests that this information remain confidential. 624.200 Test Boring and Drill Hole Data {overburden removed}

Currently, there are no plans to remove overburden from above the coal seam to be mined. Regulations related to overburden removal do not apply to this M&RP.

624.300 Test Boring and Drill Hole Data (overburden not removed)

The drill logs and chemical analyses required by regulations 614-301-624.310 through 614- 301-624.330 are presented in Appendices 6-1 and 6-2.

lithologic Logs. Lithologic logs of drill holes are presented in Appendix 6-1. The applicant requests that this information be kept confidential .

• 6-16 Canyon Fuel Company, LLC Mining and Reclamation Plan SCM/Dugout Canyon Mine May 1998

Acid, Toxic, and Alkaline Chemical Analyses (above and below the coal seam). The chemical analyses for acid- and toxic-forming and alkalinity-producing materials from the roof and floor rock material above and below the Rock Canyon and Gilson coal seams are provided in Appendix 6-2. Samples for these analyses were obtained from a fresh coal outcrop a few hundred feet into the abandoned Rock Canyon coal seam mine and approximately 800 feet into the Gilson coal seam mine in Dugout Canyon. The location of the Gilson seam sample site is illustrated on Figure A-1 in Appendix 6-2. Using the parameters listed in Table 2 in the r= "Guidelines fu nagement of To .~ verburden for Undergroun9 and Surfac Mining", no values outside of the acceptable range were reported.

Acid, Toxic, and Alkaline Chemical Analyses (coal seam). The chemical analyses discussed above are also representative of the coal bed to be mined. Samples for these analyses were also obtained from a fresh coal outcrop a few hundred feet into the abandoned Rock Canyon coal seam mine in Dugout Canyon. The results of these analyses are reported in Appendix 6- 2.

Roof and Floor Rock Clay Content. The clay content of two roof and floor rock samples taken from within an abandoned portal in the Rock Canyon coal seam in Dugout Canyon was determined analytically. The roof rock clay content was measured at 7.6 % while the floor rock clay content was measured at 9.6%. Two samples for roof and floor analysis were also obtained from the Gilson seam. The roof rock clay content was measured at 19.6% while the floor rock clay content was measured at 8.6%. Copies of the laboratory data sheets for this analysis is included in Appendix 6-2. The logs of drill holes within the permit area (Appendix 6-1) indicate that the lithology of the stratum immediately above and below the mineable coal varies within the permit area.

Ground Water Occurrence. The depth to ground water was not noted on the logs prepared by the geologist onsite during the drilling of the exploration holes (Appendix 6-2). Since the holes have been plugged and abandoned, with the exception of those retained for ground water monitoring (Chapter 7), revisiting the locations for the purpose of obtaining ground water information is not feasible.

6-17 Canyon Fuel Company, LLC Mining and Reclamation Plan ' • SCM/Dugout Canyon Mine October 2010 625 Additional Geologic Information

It is not anticipated that any additional geologic data will need to be collected forthis site. During the drilling of degassification wells geologic data may be collected, refer to Chapter 6 of the Degassification . amendment for details.

626 Sampling Waivers

A sampling waiver is not requested at this time for this site.

627 Description of the Overburden Thickness and Lithology

Overburden thickness above the coal seam ranges from approximately 600 feet in the southern portions of the permit area to over 2400 in the northern and northeastern portions (Plate 6-4). Stratigraphically, the overburden consists of the Upper Blackhawk Formation, which contains the coal seams, the Castlegate Sandstone, the Price River Formation, the North Horn Formation, and the Flagstaff Formation as described ' • in Section 624.100 of this M&RP.

630 OPERATION PLAN

631 Casing and Sealing of Exploration Holes

The information addressing regulations for casing and sealing of exploration holes isfound in Section 765 ofthis M&RP. This includes both the temporary and permanent casing and sealing of drilled holes and exploration holes and boreholes.

632 Subsidence Monitoring

Subsidence and subsidence monitoring points are discussed in detail in Section 525 ofthis M&RP and a map showing the subsidence monitoring locations is provided in the annual report.

INCORPORATED • 6-18 -Eo a 8 2011 Div. of Oil, Gas &Mining Canyon Fuel Company, LLC Mining and Rec lamation Plan SCM/Dugout Canyon Mine May 1998

640 PERFORMANCE STANDARDS

641 Exploration and Drill Holes

The performance standards used in the casing and sealing of all exploration holes and drill holes are outlined in Section 765 of this M&RP.

642 Monuments and Surface Markers of Subsidence Monitoring Points

The performance standards used in the reclamation of all monuments and surface markers used as subsidence monitoring points are outlined in Section 525.

6-19 Canyon Fuel Company, LLC Mining and Reclamation Plan SCM/Dugout Canyon Mine May 1998

REFERENCES:

Anderson, P.B. 1983. Geologic Map of the Pine Canyon Quadrangle, Carbon County, Utah. Utah Geological and Mineral Survey, Map 72.

Balsley, John K. 1980. Cretaceous Wave-dominated Delta Systems: Book Cl iffs, East Central Utah. AAPG Field Guide, p. 163.

Clark, F.R. 1928. Economic Geology of the Castlegate, Wellington, and Sunnyside Quadrangles, Carbon County, Utah. U.S. Geological Survey Bulletin 793, p 165.

Doelling, H .H. 1972. Central Utah Coal Fields: Sevier-Sanpete, Wasatch Plateau, Bookcliffs and Emery. UGMS Mon. Ser. 3.

Fisher, D.J., Erdmann, C.E., and Reeside, J .B., Jr. 1960. Cretaceous and Tertiary Formations of the Book Cliffs, Carbon, Emery, and Grand Counties, Utah County and Garfield and Mesa Counties, Colorado. U.S. Geological Survey Professional Paper, p.80.

Harms, J.C., et. al. 1975. Depositional Environments as Interpreted from Sedimentary Structures and Stratification Sequences. SEPM Short Course No.2, p. 161.

Intrasearch, Inc., 1998. Geologic Map of the Dugout Canyon and Kaiser North Lease Areas. - Unpublished Canyon Fuel Company, LLC internal report.

Marley, W.E., et al. 1979. Coal Accumulation in Upper Cretaceous Marginal Deltaic Environments of the Blackhawk Formation and Star Point Sandstone, Emery, Utah. Utah Geo!. V. 6, No.2.

McGookey, D.P. 1973. Cretaceous System, in Geologic Atlas of the Rocky Mountain Region. Rocky Mtn. Assoc. Geol., pp 190-228.

Nethercott, M. 1985. Geology of the Deadman Canyon Quadrangle, Carbon County, Utah. Utah Geological and Mineral Survey.

Peterson, F. and Ryder, R.T. 1975. Cretaceous Rocks in the Henry Mountains Region and Their Relation to Neighboring Regions. Four Corners Geological Society Guidebook, 8th Field Conference, Canyonlands. p.182-183.

Spieker, E.M. 1931. The Wasatch Plateau Coal Field, Utah. USGS Bull. 819, p 46.

Stokes, W.L. 1977. Subdivisions of the major physiographic provinces in Utah. Utah Geology, v. 4, no. 1, p. 1-17.

Young, R.G. 1955. Sedimentary Facies and Intertonguing on the Upper Cretaceous of the Book Cliffs, Utah. Geological Society of America Bulletin, v. 66, p. 177-202. •

6-20 • Place in Confidential Folder

Appendix 6-1

• Dugout Canyon Mine P.O. Box 1029 ARCH WESTERN Wellington, UT 84542 (435) 637-6360 BITUMINOUS GROUP,lLC. Fax (435) 636·2897 • A Sub8idary of Arch Western Resources, LLC . August 31, 2006

Mr. John T. Blake School and Institutional Trust Lands Administration State of Utah 675 East 500 South, Suite 500 Salt Lake City, Utah 84102-2818

Subject: Permission to Core Seams at Degas Well Site G-14A, Dugout Canyon Mine

Dear Mr. Blake:

Per discussions at the Dugout Canyon Mine on August 31, 2006, we request SITLA's approval to core the coal seams at degas well site G-14A located in the northern part of SITLA Lease ML-48435. Information obtained from the hole would be valuable in characterizing the seam where data is sparse. Furthermore, it would provide information . necessary to meet data adequacy requirements for a soon to be submitted Lease Modification. Dugout Canyon Mine is considering acquisition of coal for eastward and • northward expansion of longwall panels.

Both the Rock Canyon and Gilson coal seams are planned to be cored at the site. The coal core would be used for the analysis of gas content and coal quality. Rock core may be tested for mechanical strength properties. The hole would be geophysically logged and the core would be described in detail. The hole would be cased for use as a degasification site and left open for venting during mining. However, the coal sequence would be cemented upon completion of drilling.

Exploration data generated from site G-14A would be provided to SITLA. This data would include but not be limited to copies of the geophysical log, geologists core descriptions, analytical data, and completion records.

Dugout Canyon Mine thanks you for your consideration and awaits approval of this addition to the drilling program.

Respectively Submitted,

INCORPORATED Erwin Sass General Mine Manager SEP 1 3 2006

Cc: D. Spillman Oi\!, of Oil, GelS 8t N'llnlng • Sitla File

Dugout Canyon rvline Canyon Fuel Company, LLC Mining and Reclamation Plan SCM/Dugout Canyon Mine March 1998

APPENDIX 6-1

Drill Hole Logs (CONFIDENTIAL FOLDER) Canyon Fuel Company, LLC Mining and Reclamation Plan SCM/Dugout Canyon Mine March 1998

APPENDIX 6-2

Rock Canyon Coal Seam Roof and Floor Rock Chemic:a~1 ~A~n::a ~ly:se:s~----J (CONFIDEN1-'AL FOLDER)