The Engineering and Mining Journal 1905-07-06: Vol 80 Iss 1
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INDEX hjeEngineering^ Mining Journal VOLUME LXXX. JULY TO DECEMBER 1905 THE ENGINEERING AND MINING JOURNAL INCORPORATED 505 Pearl Street, NEW YORK July 6, 1905. THE ENGINEERING AND MINING JOURNAL. I and subordinate feldspar of any kind, with oidal fractures. When porphyritic this be¬ 2sE>^OINEERING^ or without other minerals. comes porphyritic-perlite (f. n.). 6.. Peridotrtes (f. n.) are granular, igne¬ 4. Pumice (f. n.) is a highly vesicular Mining ^Journal ous rocks "composed of olivine and ferro- glass, white or very light-colored. When magnesian minerals, with little or no feld¬ porphyritic this becomes porphyritic- Rock Classification in the Philippines. spar or other minerals. pumice. The following circular has been issued 7. Pyroxenites (f. n.) are granular, ig¬ REFERENCES. by H. D. McCaskey, Chief of the Mining neous rocks composed of pyroxene, with Reference is suggested in connection Bureau of the Philippines, for the instruc¬ little or no feldspar or other minerals. with the above to the following: tion of field assistants; also for the bene¬ 8. Hornblendites (f. n.) are granular, ig¬ 1. ‘Quantitative Classification of Igne¬ fit of miners, prospectors, teachers, inves¬ neous rocks composed of hornblende, with ous Rocks.’ By Whitman Cross, Joseph tigators and others interested in mining little or no feldspar or other minerals. P. Iddings, Louis V. Pirsson, Henry S, and exploration in the Islands: Division B—Aphanites : Washington. The following system for megascopic* (0) Non-porphyritic. These are divided 2. ‘Geology, Volume I. Geologic Pro¬ and field classification of the igneous into— cesses and their Results.’ By Thomas C. rocks, as proposed by the eminent petro- 1. Felsites (f. n.), or aphanitic igneous Chamberlain and Rollin D. Salisbury. graphers, Messrs. Cross, Iddings, Pirs- rocks, non-porphyritic and light-colored. - [To these should also be added ‘A son and Washington, added to with re¬ without vitreous luster. Handbook of Rocks, for Use without the spect to the use of the word ‘dolerite’ by 2. Basalts (f. n.), or aphanitic igneous Microscope,’ by James F. Kemp.—Editor.] Messrs. Chamberlain and Salisbury, of the rocks, non-porphyritic and dark-colored. University of Chicago, and modified for (b) Porphyritic. These porphyries are further simplicity by the Chief of this Bu¬ divided, depending upon the dominant Construction of Steel Tanks for reau by the omission of all synonyms ter¬ phenocryst,* into— Cyanide Works. minating in ‘phyre’ with the exception of 1. Quartz-porphyry (f. n.), composed of The following notes are taken from the the two retained words, ‘melaphyre’ and quartz phenocrysts and aphanitic matrix. specifications for a small cyanide plant, in ‘leucophyre,’ is hereby provisionally 2. Feldspar-porphyry (f. n.), composed which the leaching tanks were 15 ft. in adopted for official use in the work of of feldspar phenocrysts and aphanitic diameter and 4 ft. deep, and the solution the Mining Bureau. The letters (f. n.), matrix. tanks were 15 ft. in diameter and 6.5 ft. signifying ‘field name,’ will be invariably 3. HornWende-porphyry (f. n.), com¬ deep. written after each w'ord of this classifica¬ posed of hornblende phenocrysts and The leaching tanks are constructed of tion used unless a statement appears aphanitic matrix. No. 8 steel, B. W. G. The bottoms are otherwise in a bulletin or report, reproduc¬ 4. Mica-porphyry (f. n.), composed of flanged and riveted to the sides by ^-in. ing the outline herewith as adopted or mica phenocrysts and aphanitic matrix. rivets, pitch. The bottom has a to the effect that the system is used as 5. Angite-porphyry (f. n.), composed of drop of Vi in. from outside to center. authorized and directed herein. augite phenocrysts and aphanitic matrix. Around the upper rim of the tank an iron Every effort will be made to explain and 6. Olivine-porphyry (f. n.), composed of band 2j4x^ in. is riveted on the outside popularize this classification, to the end olivine phenocrysts and aphanitic matrix. by ^-in. rivets with about 6-in. pitch. An that miners and others interested in the They are also divided, according to iron packing ring 2^2x54 in. is riveted on Bureau work may use terms in harmony color, into Leucophyres (f. n.), which in¬ the inner side of the tank at the bottom therewith. clude all light-colored porphyritic, aphan¬ with ^-in. rivets, 6j4'in. pitch, the ring DIVISIONS OF IGNEOUS ROCK. itic, igneous rocks, and Melaphyres (f. n.), being set out in. by washers, so as to A. Phanerites are rocks whose mineral which include all dark-colored porphy¬ leave a space between the ring and the components can be seen with the unaided ritic, aphanitic igneous rocks. Depend¬ side of the tank. A similar ring is riveted eye. ing upon the phenocrysts again we have— around the main casting for the discharge B. Aphanites are rocks whose mineral 1. Quartz-leucophyre (f. n.), or light- gate in the center of the tank. components can partly be seen with the colored quartz-porphyry. The solution tanks are constructed of unaided eye, the remaining lithoidal ma¬ 2. Feldspar-leucophyre (f. n.), or light- No. 10 steel, B. W. G., in the same man¬ terial being not resolvable into its com¬ colored feldspar-porphyry. ner as the leaching tanks, except that the ponent parts. 3. Hornblende-leucophyre (f. n.), or central discharge gate and the packing C. Glasses are rocks with vitreous luster 1 ight-colored hornblende-porphyry. rings are omitted, and the bottoms Rro in the whole or a part of the mass. Quartz-melaphyre (f. n.), or dark- flat instead of concave. The outlets are- Division A—Phanerites: colored quartz-porphyry. made through wrought-iron flanges, riv¬ 1. Granites (f. n.) are granular, igneous 5. Feldspar-melaphyre (f. n.), or dark- eted on at the proper places and tapped' rocks with dominant quartz and feldspar colored feldspar-porphyry. for pipes of the desired diameter. of any kind, with mica, hornblende or 6. Hornblende-melaphyre (f. n.), or Specifications for such tanks should ex¬ other minerals in subordinate amount. dark-colored hornblende-porphyry—and so plicitly provide that they be made water¬ 2. Syenites (f. n.) are granular, igne¬ on, the second word indicating the color, tight, which, of course, depends largely ous rocks with dominant feldspars of any and the first the phenocryst. of the por¬ upon the character of the work in fitting kind, with hornblende, pyroxene, mica or phyry described. the parts together, riveting, etc. other minerals, but with little or no quartz. Division C—Glasses; 3. Diorites (f. n.) are granular, igneous 1. Obsidian (f. n.) is vitreous rock of According to the Engineer, of London, rocks with dominant hornblende and sub¬ any color, usually black, often red, less an important development has taken place ordinate feldspar of any kind, with or often brown or green. When porphyritic in several of the principal mineral oif without other minerals. this becomes porphyritic-obsidian (f. n.). works in Scotland. This is the introduc¬ 4. Gabbros (f. n.) are granular, igne¬ 2. Pitchstone (f. n.) is a rock resinous tion of electrical power in place of steam- ous rocks with dominant pyroxene and in appearance, less lustrous than obsidian, driven machinery. Pumpherson has just subordinate feldspar of any kind, with or and lighter-colored. When porphyritic this completed the installation at a cost of without other minerals. becomes porphyritic-pitchstone (f. n.). £17,204. Tarbrax, a new concern, is alt 5. Dolerites (f. n.) are granular, igneous 3. Perlite (f. n.) is a glassy rock with worked by electricity; and Philpstoun is. rocks with any dominant ferro-magnesian perlitic texture produced by small spher- at present having a power-house erected mineral, not megascopically determined, and plant built up. together with a range * Crystals large enough to be visible to the > Visible to the naked eye. naked eye. of new Stirling mechanical-stoking boilers. THE ENGINEERING AND MINING JOURNAL. The Minerals of Maguarichic. However, it is not the purpose thing new. Twinning of the usual ‘swal- BY RUFUS M. BAGG, JR. Qr of low-tail’ type occurs, and with these crys- Mexico is full of interesting geological these veins, but rather to point out some tals (lining quartz cavities) there are problems waiting to be worked out This interesting crystallizations which hav. handsome examples of proustite, crystal¬ is true also of the wonderful minerals observed. lized and massive, one piece of which is she possesses. Some interesting mineral l- Selenite crystals with included n an inch thick, two inches in diameter, species lie on the table before me; they of stephanite. Crystals of beautiful trans- and is of a bright ruby-red color. Similar come from the district of Rayon, State of parent monoclinic selenite occur at La Luz crystallizations are reported on the adja¬ Chihuahua, from the old Maguarichic property, and in some instances they con- cent mines near La Luz. 2. Dodecahedral fluorite. Fluorspar is not rare in metallic ores; but when pres¬ ent it is generally of the cubic habit. Octahedral crystals are also abundant in some mines, but I am not aware of many- perfect dodecahedral forms being found. These fluorites are of a deep sea-green color; they occur both as perfect uncom¬ bined units and also in twin-crystal forms (twinning on the octahedral face). In the Santa (iertrudis mine, above Maguarichic. octahedral fluorite is present. These crys¬ tals vary in diameter from one-quarter to one-half inch, and rest upon a crystallized base of sphalerite, quartz and stephanite. Pyrite and minute cry-stals of chalcopyrite are also present. Some of this ore runs M.\Gr.\RICHIC, MEXICO. as high as ^ oz. gold per ton, and this, with high-grade petanque (antimonial camp, which is reached by a three-days’ tain masses of stephanite.