# Joint Appendix Vol II — Amoco Production Co. v. Southern Ute Tribe > Briefs, arguments, decisions, and more. URL: https://www.frixlaw.com/law-library/documents/brief%3Amicro_IA40385014_0245%3A14 ## Record - **Collection:** Supreme Court brief - **Document type:** Joint Appendix Vol II - **Published:** January 1, 1999 - **Citation:** 526 U.S. 865 ## Text No. 98-830 IN THE Supreme Court of the United States OCTOBER TERM, 1998 AMOCO PRODUCTION COMPANY, on behalf of itself and the class it represents,* v. Petitioners, SOUTHERN UTE INDIAN TRIBE, and Bruce BassitT, Secretary of the United States Department of Interior, et al., Respondents. On Writ of Certiorari to the United States Court of Appeals for the Tenth Circuit JOINT APPENDIX VOLUME II CARTER G. PHILLIPS ** THOMAS H. SuHipps ** STEPHEN B. KINNAIRD FRANK E. MAYNES SmDLEY & AUSTIN MAYNES, BRADFORD, 1722 Eye Street, N.W. Surpps & SHEFTEL, LLP Washington, D.C. 20006 P.O, Box 2717 (202) 736-8000 Durango, CO 81302 CHARLES L. KAISER (970) 247-1755 ANTHONY J. SHAHEEN Counsel for Respondent Davis, GRAHAM & Southern Ute Indian Tribe Stusss LLP Sern P. WAXMAN ** Suite 4700 Solicitor General 370 Seventeenth Street Department of Justice Denver, CO 80202 Washington, D.C. 20530 (303) 892-9400 (202) 514-2217 Counsel for Petitioner Counsel for Federal Respondents Amoco Production Company f (class representative) ( Additional Counsel Listed on Inside Cover) * Named classnm nbers listed in Addendum A of Petitioners’ Brief. ** Counsel of Record. PETITION FOR CERTIORARI FILED: NOVEMBER 18, 1998 CERTIORARI GRANTED: JANUARY 22, 1999 ORDER GRANTING CERTIORARI AMENDED: JANUARY 29, 1999 Gary L. PAULSON Resecca S. McGEE DAvip E. Bropy AMOCO CORPORATION 1670 Broadway Denver, CO 80201 (303) 830-4040 Counsel for Petitioner Amoco Production Company (class representative ) G. R. MILLER MCDANIEL, Baty & MILLER, LLC 1040 Main Avenue P.O. Box 1157 Durango, CO 81302 (970) 247-1113 Counsel for Certain Named Class Members Scott B. McELRoy ALICE E. WALKER GREENE, MEYER & MCELROY, P.C. 1007 Pear! Street Suite 220 Boulder, CO 80302 (303) 442-2021 MICHAEL T. MCCONNELL LONG & JAUDON 1600 Ogden Street Denver, CO 80218-1414 (303) 832-1122 Counsel for R Southern Ute Indian Tribe OE se te - t B TABLE OF CONTENTS VOLUME I Court of Appeals Docket Entries —..... First Amended Complaint ................ nn. Matthew J. Mavor Affidavit and Report .......... Douglas M. Smith Affidavit and Report Dan Yee Affidavit and Report ..........---....-. Documents Regarding the John J. Patterson ne enneite Shemas VOLUME II Marius R. Campbell, Contributions to Economic Geology, 1906, Part IIl—Coal, Lignite, and Peat, U.S.G.S8. Bulletin 316, H.R. Doc. No. 823, 59th Cong., 2d Sess. (1907) ....... Rollin T. Chamberlin, i ae eae 8 Mine Gases and Dust, U.S.G.S. Bulletin $83, H.R. Doc. No. 1538, 60th Cong., 2d Sess. (1909) 00000000 Papers on the Conservation of Mineral Resources, U.S.G.S. Bulletin 394, H.R. Doc. No. 1554, 60th ae eee ee Cassius A. Fisher, Depth and Minimum Thickness of Beds as Limiting Factors in Valuation reprinted in The Valuation of Public Coal Lands, U.S.G.S. Bulletin 424, H.R. Doc. No. 502, 61st Cong., 2d Sess. (1910) 401 415 473 | ii TABLE OF CONTENTS—Continued Horace C. Porter and F.K. Ovitz, The Escape of Gas From Coal, U.S. Bureau of Mines Technical SS Robert H. Fernald, wip slid ti tei thas Doioee and of the Internal-Combustion Engine in the Util- ization of Fuels, U.S. Bureau of Mines Technical (EE Phillip J. Wilson and J.H. Wells, Coal, Coke, and Coal Chemicals, Chemical Engineering Series Harry Perry, The Gasification of Coal, 230 Scien- tific American, No. 8 (Mar. 1974) .........................-. Robert A. Myers, Coal Handbook (1981) ................ William F. Clark and Tom Hemler, Completing, Equipping, and Operating Fruitland Formation Coal-Bed Methane Wells in the San Juan Basin, New Mexico and Colorado reprinted in James E. Fasset, Geology and Coal-Bed Methane Resources of the Northern San Juan Basin, Colorado and New Mexico, Rocky Mtn. Ass’n of Geologists (1988)... Jeffrey R. Levine, Coal Composition, as Related to the Mode of Occurrence of “Coalbed Methane” Ne CET a OA OC NOTICE Page The following documents have been omitted in the printing of this Joint Appendix. They are reproduced in the Appen- dix to the Petition For A Writ Of Certiorari on the pages indicated below : 9s PP Opinion of the Court of Appeals (Zn Banc) ........ Opinion of the Court of Appeals (Panel) ........... iii TABLE OF CONTENTS—Continued E. Classification and Valuation of Coal Lands, 37 Pub. Lands Dec. 653 (1909) ..... 137a F. Ownership of And Right to Extract Coalbed Gas in Federal Coal tesa 88 Interior Dec. 538 I ae ee te Ae See 140a G. eatin ty Guile Unitans Cites dn Oh a te Lease for Lands in the Jicarilla Apache Reser- vation, 98 Interior Dec. 59 (1990)... 160a H. Department of Interior, a Manual 3 Pe EM SE, Sear Se See 178a I. Map of Majer U.S, Coated Methane Resvuress. 18la The following additional documents have also been omitted in the printing of this Joint Appendix. They are reproduced in the Appendix to the Respondent Southern Ute Indian Tribe’s Brief In Opposition on the pages indicated below: Act of March 3, 1909, 35 Stat. 844 (“1909 Act”). la Act of June 22, 1910, 36 Stat. 583 (“1910 Act”). 3a Pub. L. No. 105-367 (“Enzi Act”) 6a Bureau of Mines, Bulletin 65 (1913) (cover page) _ 9a Bureau of Mines, Bulletin 65, Plate I (map)... 10a 401 59TH CONGRESS DocUMENT 2d Session No. 823 HOUSE OF REPRESENTATIVES Bulletin No. 316 Series—A. Economic Geology, 98 B. Chemistry and Physics, 51 DEPARTMENT OF THE INTERIOR UNITED STATES GEOLOGICAL SURVEY Georce Oris SMITH, DiRECTOR ECONOMIC GEOLOGY 1906 Part IIl.—COAL, LIGNITE, AND PEAT MARIUS R. CAMPBELL Geologist in Charge WASHINGTON GOVERNMENT PRINTING OFFICE 1907 402 Bulletin No. 316 Series—A. Economic Geology, 98 B. Chemistry and Physics, 51 DEPARTMENT OF THE INTERIOR UNITED STATES GEOLOGICAL SURVEY GEorGE Oris SMITH, DIRECTOR CONTRIBUTIONS TO ECONOMIC GEOLOGY 1906 Part Il.—COAL, LIGNITE, AND PEAT MARIUS R. CAMPBELL Geologist in Charge WASHINGTON GOVERNMENT PRINTING OFFICE 1907 403 CONTRIBUTIONS TO ECONOMIC GEOLOGY, 1906, PART II. COAL, LIGNITE, AND PEAT. Marius R. CAMPBELL, Geologist in Charge. INTRODUCTION. By Marius R. CAMPBELL. NEED OF INVESTIGATION. The constantly growing consumption of coal in the United States has led to the opening of mines in almost every State in the Union and it has also stimulated pros- pecting to a marked degree. This condition of affairs has created a strong demand for information concerning the extent of the coal fields, the geologic relation of the beds, and the quality of the coal. In the comparatively un- known coal fields of the West the demand is for general information regarding the extent, number, and thickness of the beds and the quality of the coal. In the better known fields the demand is for detailed information which will enable the prospective operator to know how much of any one coal bed is available, and how it lies, so that he may locate his mine in the best position for economic work. 404 In order to meet this growing demand the Geological Survey has been giving more and more attention to the subject of coal, both as regards its geologic relations and its technology. The need for information in both branches is imperative, for, although the amount of coal in the various fields seems so great as to be well nigh inexhausti- ble, the consumption is increasing so rapidly that already the question of a future supply of fuel is a serious one and the Government is surely justified in using every means possible to conserve the supply for the use of fu- ture generations. Accordingly the technologic branch of the Survey is engaged in studying the fuel problems in order to devise, if possible, less wasteful methods of min- ing and more economical methods of utilizing the coal after it is mined. Our chief fuels are coal, oil, and wood. Wood already is almost a thing of the past; oil, although used extensively in some parts of the country for the production of power, is necessarily of limited occurence and before long may cease to be an important factor in the problem. Coal, therefore, is the fuel of the present, and, so far as can be seen, will continue to lead in this particular for a long time to come. The importance of the coal industry at the present time is well illustrated by a comparison of the values of the leading mineral products of the United States for the year 1905. Values of six of the leading mineral products of the United States in 1905." REESE one eka eee Seibel, $476,756,963 Iron ..... SS eS OL Se eS 382,430,000 Clay products ......... POPES op as) Sv 149,687,188 I ictcsdaprerncingheint Pe ae pe Ae Ta AS 139,795,716 RII... . cssscsinsniatanigndenetharennemmesteg . 125,720,254 I RES IES perce fe 122,402,683 * Mineral Resources U.S. for 1905, U.S. Geol. Survey, 1906. 405 So far as fuels are concerned the work of the Geological Survey may be divided into three classes—geologic, tech- nologic, and statistical, the last of which is in charge of the division of mineral resources. The object of this report is to give, in a brief way, a synopsis of the results accompanied in the various branches of the work during the last year in advance of the more detailed reports cov- ering the same subjects. GEOLOGIC WORK. All geologic work en the mineral fuels of the United States is under the general supervision of the writer. The work is of various grades and degrees of precision, de- pending on the needs of the public and the condition under which the surveys are carried on. {n that part of the country west of the 100th meridian the coal fields are comparatively unknown, and the work of the Survey is largely exploratory. Rapid reconnaissance surveys are made over large areas to determine the limits of the field and to obtain such information regarding the number and character of the coal beds and their attitude as may be possible in the present undeveloped condition of the field and with the hasty method of examination. Where the outlines of the fields are already fairly well known the work is largely devoted to a more or less detailed investigation of the number and thickness of the coal beds, the quality of the coal, and the best locations for economical development of the field. In the eastern fields information is needed almost as badly as in the West, but the work is of a much more detailed character and involves not only a thorough study of the geologic conditions under which the coal occurs, but also a study of the quality of the coal and its adaptability to various commercial uses. The reports here presented cover results obtained wholly or in part during 1906. Geologic work has been done in ihe various States as follows: 406 Pennsylvania.—Since 1900 the examination of the Pennsylvania coal field has been carried on through the cooperation of the State and Federal authorities, but the field work has been done entirely by the geologists of the United States Geological Survey. In this time very detailed surveys have been made of most of the Pittsburg coal region of the southwest corner of the State, of a large area in the eastern part of the bituminous coal field in Indiana, Cambria, and Clearfield counties, and a part of the Allegheny Valley, embracing an area of about 5,000 square miles. All coal work in this State is under the general direction of George H. Ashley, who was assisted during the past year by W. C. Phalen, Edwin F. Lines, M. J. Munn, and Frederick B. Peck. Surveys were carried on in Cambria, Clarion, and Allegheny counties, and some of the results are given in this volume in papers entitled “Coal in the Clarion quadrangle, Clarion County, Pa.,” by E. F. Lines, and “The coal resources of Johnstown, Pa., and vicinity,” by W. C. Phalen. Virginia-Kentucky.—A reconnaisance survey was made of a district in the central part of the Appalachian field under the general supervision of George H. Ashley. The building “ ~ new branch line from the Chesapeake and Ohio Railway up Russell Fork of Big Sandy River to the Virginia line and the beginning of construction of the South and Western Railroad from the end of this branch to the Atlantic coast promises to open in the near future one of the largest and best tracts of coal land in the central Appalachian region. In order to be able to furnish information on this interesting and economically impor- tant region, a detailed reconnaissance was made by Ralph W. Stone, assisted by C. W. Dodge, on both sides of the Virginia-Kentucky State line, and the more important results will be found in three papers in this bulletin by Mr. Stone entitled “The Elkhorn coal field, Kentucky,” “Coal mining at Dante, Va.,” and “The Russell Fork coal field, Virginia.” io es wittal 2 es oD Oe Oe 407 Alabama.—For several years Charles Butts has been engaged in a close, detailed survey of the coal fields in the vicinity of Birmingham, including much of the War- rior basin. During the past year Mr. Butts was assisted by Chester W. Washburne, and the work was carried to the east into the Cahaba coal field. Time did not permit the survey of the entire field, but the northern part was examined thoroughly, and a brief account of the results of this work may be found in a paper by Mr. Butts en- titled “The northern part of the Cahaba Alabama.” densa Ilinois.—In Illinois the examination of the coal field is carried on both by the State Geological Survey and by the Federal organization, with the understanding that each shall supply to the other manuscript reports on the area or areas investigated. During the last year the work of the Federal Survey was confined to two 15-minute quad- rangles in Gallatin, Saline, White, and Hamilton counties, and the results are embodied in a paper in this volume by Frank W. De Wolf entitled “Coal investigations in the Saline-Gallatin field, Illinois.” Arkansas.—A demand for more detailed information regarding the Carboniferous coal field of Arkansas than is contained in the reports of the State Geological Survey led the Federal organization to make an examination of this field in the early part of the past summer. The work was done by Arthur J. Collier, assisted by Carl D. Smith, Sidney Paige, and R. D. Mesler. This work is of especial value, inasmuch as it has established the identity of the principal coal beds at the east and west ends of the field, and has thrown considerable light on the distri- bution of the workable coals, a point that has been troubling the operators for a number of years. A brief account of this work is given by Mr. Collier in a paper enti*led “The Arkansas coal field.” Montana.—The coal fields of Montana are probably more extensive than those of any other State, but they 408 known except along the main lines of rail- i mines have a opened, either to supply fuel for locomotive uses or for the great copper smelters of the Butte region. The quality of the Montana coal is exceedingly varied, but as a rule only the better grades are being mined at the present time. st important piece of geologic work carried on in ‘aes duine 1906 was the careful mapping of the Great Falls coal field by C. A. Fisher, assisted by W. R. Calvert, H. M. Eakin, A. J. Hazlewood, and J. D. Pollock. Geologically this field is most interesting, since the coal occurs in the Kootenai (Lower Cretaceous ) formation, which is not known to carry coal in any other part of the United States, except possibly in the Black Hills region of South Dakota and Wyoming. The field was carefully mapped from Missouri River eastward along the foothills of the Little Belt Mountains as far as Stan- ford. A brief synopsis of the results is given in a paper by Mr. Fisher entitled “The Great Falls coal field, Montana.” Bear Creek and Red Lodge fields of Carbon Pin were examined by N.H. Darton, who traced the Red Lodge group of coal beds for a considerable distance to the point where they are concealed by the overlying Tertiary rocks, and the Bridger coal bed from a point near the Wyoming line northward to Joliet. An account of this field by Mr. Darton is entitled “Coals of Carbon County, Mont.” t lignite field of the eastern part of the State “saa be A.G. Leonard, assisted by W. R. Hol- gate and W. H. Clark. This party made an exploratory trip from Glendive to Miles City and thence northward by way of Jordan to Hell Creek on Missouri River. An account of this trip and of the coal beds and other strata exposed will be found in a paper by Mr. Leonard entitled “Coal fields of parts of Dawson, Rosebud, and Custer courities, Mont.” a ee Se ee 409 Wyoming.—Wyoming is one of the great coal-producing States of the Union. This coal is extensively developed along the Union Pacific and Oregon Short Line railroads at Hanna, Rock Springs, and Kemmerer. It is also mined to some extent at Glenrock and Big Muddy on the Chi- cago and Northwestern Railway and along the Burlington system at Sheridan and Cambria. In addition to these well-known localities, there are immense areas of coal land along Powder River from a point north of Casper to the Montana line, in the Bighorn Basin, in Uinta County north of Kemmerer, and in Carbon County west of Rawlins. During the past year the Hanna field of Carbon County was rather thoroughly explored by A. C. Veatch, assisted by Max A. Pishel, Max W. Ball, and Spencer R. Logan. A brief account of this work is given by Mr. Veatch in a paper entitled “Coal fields of east-central Carbon County, Wyo.” C. E. Siebenthal made a hasty examination of the coal beds in the western part of the Laramie basin, and a brief account is given by him in a paper entitled “Coal of Laramie Basin, Wyoming.” During 1905, A. C. Veatch, assisted by A. R. Schultz, made an examination of the southern Uinta County field from the Utah State line to a point north of Kemmerer. A short account of this work appeared in Bulletin No. 285, and a full report is contained in Professional Paper No. 56, entitled “Geography and geology of a portion of southwestern Wyoming, with special reference to coal and oil.” During the past year this work was carried northward by Mr. Schultz, assisted by E. Eggleston Smith. The country is exceedingly rough and mountainous, but the coal fields were mapped with considerable care as far as Snake River. This region is scarcely accessible at the present time and little is known regarding the coals, but in the event of the construction of a railroad line along Snake River it seems quite possible that much of 410 the area of this field would become accessible by branch lines from the main trunk system. A brief account of this field will be found in a paper by Mr. Schultz entitled “Coal fields in a portion of central Uinta County, Wyo.” In the central part of the State there is a large syncline of coal-bearing rocks which in most places is covered by Tertiary sediments to such a depth that it is not accessible, but here and there along the rim of the basin coal beds are exposed. This is the case in the vicinity of Lander, where there is a small coal field that was examined by E. G. Woodruff. A very brief account of this field is given by Mr. Woodruff in a paper entitled “The Lander coal field, Wyoming.” Colorado.—Through the explorations carried on by the Colorado Fuel and Iron Company and the development of mines in the best and most accessible fields, the coals of Colorado are perhaps better known than those of any other western State. Nevertheless, there are a number of areas about which little information can be obtained, and it has been the aim of the Geological Survey to ex- plore these in advance of development. The largest area of undeveloped coal lies in the north- western part of the State, in Routt, Rio Blanco, Garfield, Pitkin, and Mesa counties. On the completion of the Denver and Northwestern (Moffitt) Railroad through Routt County the northern part of this great area, or the Yampa coal field, will be the first to be developed. This was examined in 1905 by N. M. Fenneman and Hoyt S. Gale, and a detailed report of their work ap- peared in Bulletin No. 297, entitled “The Yampa coal field, Routt County, Colo.” A brief account was pub- lished also under the same title in Bulletin No. 285. During the last season this survey was extended southward across the anticline of Axial Basin to the Danforth Hills and thence along the Grand Hogback southeastward to Newcastle on Grand River. This work was done by 411 Mr. Gale, who was assisted by A. K. Adams, A. L Beekly, and R. D. Crawford. A brief account of this work is given by Mr. Gale in a paper entitled “Coal fields f the Danforth Hills and Grand Hogback in northwestern ; Colorado-Utah.—The great Uinta Basin, which extends from the vicinity of Crested Butte, Colo., westward into Utah, continues in the latter State along the south side of the Uinta Mountains at least as far as Castle Gate. The center of the basin is deeply covered by Tertiary sediments, and at the western extremity these overlap the upturned edges of the coal-bearing rocks and conceal them so that the limit of the field in this direction is It is generally understood that the Book Cliffs, which beds. To supply such data George B. Ric i by W. D. Neal and Leon J. ovate = gee ees rapid reconnaissance during the last season from De ' River, Colorado, into Utah as far as Sunnyside mine of the Utah Fuel Company, where connection was made with the work of Mr. Taff, who, ee 5 : 5 durin, 1905, made a careful instrumental su of the Book Cliffs field from the Sunnyside mine westward to Castle Gate, and then southward along the east front of the Wasatch Plateau as far as Mount Hilgard, in Sevier as County. A report of Mr. Taff’s work was published i Bulletin No. 285 the title “The Book. Cliffs othe field of Utah.” A brief account of the results of the ny last year is ag by Mr. Richardson in this a paper entit “The Book Cliffs coal field between Grand River, Colorado, and Sunnyside, Utah.” Utah.—During the last year Joseph A. Taff, assisted Carl D. Smith, examined the region about Pleasant Valen 412 in the Wasatch Plateau, much more carefully than was possible during the previous year, and his report is em- bodied in a paper entitled “The Pleasant Valley coal district, Carbon and Emery counties, Utah.” The coal fields of I-on County in southwestern Utah, were hurriedly examined during the last year by Willis T. Lee, who visited them and procured samples for chem- ical analysis from the anthracite of the western extremity of the field and from the bituminous coal east of Cedar City. This is the most important field of the Southwest, as it is accessible from the San Pedro, Los Angeles and Salt Lake Railroad, and some day it may furnish fuel to most, if not all, of the desert region of the southern part of the Great Basin. A brief description of the field will be found in a paper by Mr. Lee entitled “The Iron County coal field, Utah.” New Mexico.—The largest coal field in New Mexico lies in the northeast corner of the Territory, but the coals in this field are not well known, being developed only at Durango, Colo., and Monero, N. Mex., on the northern edge, and at Gallup, on the southern edge of the basin. In- Contributions to Economic Geology for 1 , Schrader * had a brief paper embodying «The Durango-Gallup coal field of Colorado and New Mexico; Bull. U.S. Geol. Survey, No. 285, 1906, pp. 241-258. 413 In addition to the regular work noted above, the writer made a hasty examination of two small coal fields in the eastern part of the Territory—one at Capitan, in Lincoln County, and the other known generally as the Una Gato field, in Sandoval County. A brief account of latter is contained in a paper entitled “The Una del Gato coal field of Sandoval County, N. Mex.,” and of the former in a paper entitled “Coal in the vicinity of Fort Stanton Reservation, Lincoln County, N. Mex.” California.—tIn general the coals of California are of so low a grade as to be unable to stand in competition with fuel oil. As a consequence many of the miners have sus- pended operations. From time to time during the last few years reports have been made of the occurrence of a better grade of coal in Stone Canyon, in the southeastern Range, Monterey County, Cal.” During the past summer 414 J. Shober Burrows, who has made an extended study of methods of sampling and the results to be obtained therefrom. A teed coreens of Gate tls wad 0 cussion of their meaning is given by Mr. Burrows in a purposes can be made successfully from all grades bituminous coal, lignite, and even peat. The results these tests point conclusively to the substitution of pro- ducer-gas plants and gas engines for the generation of amet Ege ye Mig gh ps Be ogee ge use at the present time. The end of the steam engine is nearly in sight, and many people are wanting informa- tion regarding the present status of the producer and gas engine, in expectation of their installation in the near future. In order to supply unbiased information to the public on this important subject, R. L. Fernald, professor of mechanical engineering, Washington University, St. Louis, Mo., who has had charge of all tests made at the fuel-testing plant on the gas producer and gas engine, has prepared a brief statement which will be found in a paper entitled “The present status of the producer-gas power plant in the United States.” Another field of investigation which promises to have a distinct bearing on the better utilization of our coals is that of briquetting, and the present condition of the dustry of the United States.” 415 DEPARTMENT OF THE INTERIOR UNITED STATES GEOLOGICAL SURVEY GEorGE OTis SMITH, DIRECTOR BULLETIN 383 NOTES ON EXPLOSIVE MINE GASES AND DUSTS WITH SPECIAL REFERENCE TO EXPLOSIONS IN THE MONONGAH, DARR, AND NAOMI COAL MINES BY ROLLIN THOMAS CHAMBERLIN WASHINGTON GOVERNMENT PRINTING OFFICE 1909 —— ee 416 PRINS csitctiiciisltthinindcicsiitndiinienitinanabinietiaisisicbstnitistibeinnpestn IE, oseunemiepipaemmbiaianateliit Explosions studied ........................ sae icone a wre I i iahari in cease cstecinileanintieavetnibiiteldaien I le CN oo ere tecdecncetenccncensancenspentivensccsnncenies Possible conditions of gas in coal 00.0... .cecccccccccccccee ces Liberation of gas by crushing coal —................................ Plan of experiments .............................. icnainandntinisadlihcitie Nts CII iiiiocsantnminiincninaibbaisanttemaiteleniiarediii TN DOD deticindintitrtntteetsnditittintdeitihndvininarsnteccetinihin Gases from coal bottled in a vacuum ......................-........ 2 LEE Ln OY ee a ET TT TEE Effect of barometric changes |... EE eS EE Se ee oe Character of dust deposits 2.0.0.0... seen Cause and manner of coking —............................-..- Loss of volatile matter 2.02020... cccocneeceeeceennneeene Comparison of other dust samples Restraining factors—shale and dampness ................ BZSSSRSR8 SF SSSSRES 417 CONTENTS—Continued Practical considerations as to danger of explosions ........ Influence of seasonal change —........0...00000.. Effect of shale dust on explosions ............................. 3 Comparative inflammability of old and fresh coal dusts. Supposed danger in old dust on Significance of tests .......... Rs ILLUSTRATION FIGURE 1. Diagram showing rates of escape of meth- ig REESE AAAS ER ES a OR a") SSlssaee gees 418 NOTES ON EXPLOSIVE MINE GASES AND DUSTS, WITH SPECIAL REFERENCE TO EXPLOSIONS IN THE MONONGAH, DARR, AND NAOMI COAL MINES. By ROLLIN THOMAS CHAMBERLIN. INTRODUCTION. CHARACTER OF THE REPORT. The studies herein reported were begun as a part of researches undertaken by the United States Geological Survey looking to the more efficient utilization of the coal in the United States through the reduction of waste in its extraction, and were continued as part of further researches having regard to the conservation of the fuel resources of this country and to the lessening of injuries and fatalities in coal mining. Among other phases of the general problem to be studied were the origin of the gas which escapes into coal mines, its modes of occurrence in the coal and rock strata, and the conditions governing its outflow into the mines. The subject of relative danger from destructive explosions due to gas and coal dust in different mines belonging to different coal fields was to be one of the principal lines of investigation. But this work was barely under way when the series of unusually disastrous explosions in the Naomi, Monon- gah, and Darr mines of Pennsylvania and West Virginia, in December, 1907, afforded an exceptional occasion to observe the behavior of explosions on a large scale. Be- cause of the opportunities for study afforded by these terrific explosions, the inquiry originally planned was di- verted to the more specific investigation of the conditions 419 in these mines, and the examinations have been directed toward finding those qualities of gas anc dust which were concerned in these explosions. The following discussion, therefore, consists essentially of a report on that subject; but it is far from being exhaustive, and is to be regarded as a preliminary outline of investigations which are still in progress. EXPLOSIONS STUDIED. The first of the three mine explosions mentioned oc- curred in the Naomi mine of the United Coal Company, near Bellevernon, Pa., on Sunday, December 1, at 7:40 p. m. All the men who were within the mine at the time, fortunately only 34, were killed. Less than a week later there occurred in mines Nos. 6 and 8 of the Fairmont Coal Company at Monongah, W. Va., the most disastrous mine explosion yet recorded in the annals of American mining. The mines were com- paratively new and well laid out. Mine No. 8 had been in operation only about two years and was the pride of the Fairmont Coal Company. Mine No. 6 was first opened about four years earlier. In order to make it possible, in case of emergency, for either mine to be ventilated by the ventilating system of the other, the two sets of workings were connected underground. The F face heading of mine No. 6 led directly into No. 2 north heading of No. 8 mine. On Friday, December 6, at about 10.30 in the morning, an explosion of unusual violence swept completely through both mines, pursuing its course throughout the numerous ramifications and bursting out of the two pit mouths, located 1% miles apart, nearly simultaneously. The slope of mine No. 6 was only slightly damaged, but at the mouth of No. 8 the destruction was very great. The fan was wrecked, the engine house was demolished, and mine timbers were blown across Monongahela River. As nearly as can be determined, 361 men were killed in the two mines by the explosion. 420 While the inspection of the Monongah mines was still in progress, on Thursday morning, December 19, at about 11.20, a similar explosion wrecked the Darr mine of the Pittsburgh Coal Company at Jacobs Creek, Pa.; 238 men lost their lives in this explosion, which in number of casualties is second only to the Monongah disaster in the history of American mining. Of all the men in the mine at the time of the explosion, only one man, who happened to be within 100 feet of the surface on an old manway in a wet, unexploded portion of the mine, succeeded in escaping alive. The underground investigation of these mines was made in cooperation with Clarence Hall and Walter O. Snelling, of the United States Geological Survey, and James W. Paul, now of the Survey but at that time chief of the department of mines for West Virginia, to all of whom the author is greatly indebted for valuable assistance, suggestions, and advice. Mr. Paul will report on the nature of these explosions, the precipitating causes, their destructiveness, and the general conditions in these mines following the disasters. The present report is confined essentially to the laboratory examination of some of the explosive materials collected from these mines directly after the explosions. GASES FOUND IN THE MINES. METHODS OF COLLECTING. As soon as practicable after these explosions samples of the mine atmosphere were collected at the coal faces and from the return air ways in various parts of the mines. It was hoped that something as to the nature of the after damp might be determined, but as the exploration of the mines could be carried only where there had been a certain amount of ventilation, the samples of after damp were necessarily greatly diluted with air. With the aid of breathing helmets and compressed-air cylinders attempts 421 were made to collect after damp in the tight places where there appeared to have been little ventilation, but the subsequent analyses have shown that the proportion of after damp remaining was small. Other samples were taken to deiermine the accumulation of fire damp in the workings. The samoles of air and gas from these mines were collected for analysis in glass tubes of 125 cubic centi- meters capacity. These tubes were drawn out to a 5- millimeter bore at each end, over which was slipped a piece of red antimony rubber tubing 5 to 6 cenitmeters in length. Before entering the mine each tube was filled with water, and a tight-fitting plug of glass rod was in- serted in the rubber tubing at each end. To take a sample of the mine air the glass plugs were removed from the ends of the tube, allowing the water to run out and be replaced by air, after which the ends of the tube were securely closed by the plugs and the rubber connections tightly wired with copper wire. Glass tubes thus sealed were found to hold gas samples for several weeks with- out apparent change from leakage or diffusion. However, as a thin film of water always remains upon the walls of the tube when the gas is collected in this manner, it is inevitable that ‘a small amount of carbon dioxide be absorbed. Haldane* has called attention to the fact that when gas samples are collected in glass tubes whose walls are moist, a small amount of carbon dioxide is absorbed by the sodium silicate of the glass. If the water used be clear, the gas sample loses a small amount of carbon dioxide, but if the water used be dirty, the sample may gain carbon dioxide from the action of bacteria. The samples of gas collected in the Naomi, Monogah, and Darr mines are all subject to these criticisms. Clear water was used in every tube but one, No. 26, which had to be refilled from a pool of standing water in the mine. * Foster, Sir Clement, and Haldane, J. S., The investigation of mine air. 422 Whenever the sample could not be analyzed within a few days after it was collected, the rubber connections were completely coated with paraffin, thus preventing with certainty any passage of gas through the rubber. The samples of gas obtained from these mines were for the most part selected either from points in the workings where there appeared to be unusual quantities of fire damp, or where the presence of after damp was suspected. Other samples were collected from the return air currents to obtain information upon the general character of the air throughout certain sections of the mines. Except in one or two special cases, the samples were collected just below the roof, in order to obtain a proportion of meth- ane somewhat near the maximum present in the air. This was thought desirable because the gas near the roof would be most likely to be ignited from an open light upon a miner’s cap, and because the maximum percentage of marsh gas in an entry gives the best indication of the danger from gas. ANALYSES. The analyses of the samples of gas collected within these three mines are given in the table which follows. The first 18 analyses were made according to the tech- nical method of gas analysis described by Hempel.* The remainder of the analyses, with the exception of Nos. 23 and 29, were carried on over mercury in the apparatus devised by Professor Bone, of the University of Leeds.’ Analyses of samples of gas taken in Monongah, Naomi, and Darr mines. [Tabular Matter Omitted] “Hempel, W. M., Methods of gas analysis, 1902: technical method. * Bone, W. A., Jour. Soc. Chem. Ind., vol. 27, 1908, pp. 10-12. 423 METHANE. It will be seen from the table that the highest percent- ages of methane (CH,) were usually found in the samples collected at the faces of some of the mains. Methane in such high percentages occurred only more or less locally, either at the high points in the roof where, owing to its extreme lightness, it had accumulated, or as a thin stratum of fire damp floating along beneath the roof of an entry for a short distance from the coal face. Generally the diffusion of the gas was found to have taken place slowly in tight places where the current of air was slight, so that at a few rods from the face the percentage of methane in the air, even at the roof, was much reduced, while at the floor there was still less methane. But in some places the gas was found to have become far more evenly distributed throughout the entries. In several of the entries in the Darr mine (see analyses 21, 22, 24, and 26) fire damp was detected in such quantities by the Wolf lamp, at distances of 75 to 100 feet from the coal face, that it was not thought advisable to push on to the faces even with safety lamps. Later, with an elec- tric flash light to illumine the way, the faces of two of these three entries were visited. Tube 28, filled with air on January 4, 1908, from the face of No. 12 right butt, off entry 27, contained 7.99 per cent of methane, while tube 26, filled on January 2 at a point 80 feet from the face of this same entry, contained 4.24 per cent of meth- ane. The conditions were similar at the face of the main entry. Tube 21, filled with air from the roof of the main entry, 5 feet inby the third right crosscut, inby entry 30, contained 4.99 per cent of methane, while tube 22, filled a few minutes later at a point 20 feet inby the fourth right crosscut (about 60 feet from the face of the main), contained 6.01 per cent of methane. Two days later a sample of gas (No. 27) was taken from the mouth of a drill hole 5 inches in diameter in the face of the right air course of the main entry. In this methane amounted to 32 per cent. 424 These figures show that the percentage of methane in the air near the roof of the gassy entries diminished rapidly with increasing distance from the face. This was true even in entries where the diffusion has been fair, for the Wolf lamp at the point where tube 21 was filled indicated gas as low as 2 feet above the floor. The high percentages of methane were chiefly local. The main return air currents, and in general those parts of the entries distant from the coal face, contained methane only in very much smaller proportions. In these passageways the gases had become more thoroughly mixed by diffusion as well as diluted in the draft of air, and hence here it made less difference whether the sample for analysis was collected at the roof or near the floor. An example of this was shown in No. 1 left butt, off entry 30, in the Darr mine. Tube 20, filled at the roof of the entry 20 feet inby from entry 30, showed only 1.55 per cent of meth- ane. At this point « Wolf lamp on a tie showed a %4-inch gas cap, indicating from 1 to 1.5 per cent of methane. As only a very slight current of air was moving out of this entry, the thorough mixing of the gases was appar- ently due largely to steady diffusion rather than to the air draft. Tube 29, filled with gas-laden air from the roof of entry 28, Darr mine, about 125 feet inby No. 1 left butt, contained 2.12 per cent of marsh gas. On the floor just below nearly a %-inch gas cap was got with a Wolf lamp. The air was moving slowly. In the main return air ways the fire damp was more diluted. On December 21, two days after the explosion in the Darr mine, when the ventilation was bad, the air from the return air way just inside of the first crosscut to the left, inby from the swamp entry, contained 2.51 per cent of methane (analysis 17); but the air at this same point on January 1, when the ventilation was better, contained only 1.50 per cent of marsh gas (analysis 18). On January 2 the return air from the swamp entry only 0.58 per cent of methane (analysis 23). Two days later a Chesneau lamp registered 1.4 per cent of fire 425 where tube 18 had been filled, and 0.4 per cent in air from the swamp entry, indicating that, been a slight improvement in the char- air within these two days, the figures for 18 are probably not far from the normal Where the Chesneau lamp registered 1.4 per fire damp on January 4, and the chemical analy- gas collected January 2 gave 1.50 per cent, the Wolf lamp on each occasion showed a “%-inch gas cap. In the Naomi mine, where very high percentages of methane were found at some of the entry faces, the main return air current on the center main, 1,800 feet from the mouth of the slope, contained, on the afternoon of De- cember 14, 1907, only 0.75 per cent of marsh gas (analysis 16). At Monongah there appears to be much less gas in the mines, both locally near the coal face, and in the return air in particular. In mine No. 6 the air of the main south return air way, 50 feet from the bottom of the shaft lead- ing to the fan (analysis 9), and another sample from the main right return air way, 200 feet inby a face entry (analysis 10), contained, on December 16, 1907, only 0.22 and 0.45 per cent of methane, respectively. In mine No. 8 a test of the air collected on December 12 from the return air way opposite room 15 on the fifth right, off second north heading, showed only 0.09 per cent of methane (analysis 3). However, instead of collecting the gas from near the roof, the tube in this case was filled at a point about midway between the floor and the roof. AFTER DAMP. In all the samples of mine air collected in the Monon- gah, Naomi, and Darr mines within a few days after the explosions, the percentage of carbon dioxide greatly ex- ceeded that of carbon monoxide. But it is true that none of these samples was collected until a fair state of venti- lation had been reestablished after the explosions, such | sf z E eggEe & a Peg 426 that parties could remain in the mines for several hours. The best of the samples was No. 17, taken from the Darr mine by Clarence Hall on the afternoon of December 21, two days after the explosion. While obtaining this sample three of the party were so overcome as to be forced to leave the mine. An analysis of this air showed 1.07 per cent of carbon dioxide and 0.61 per cent of carbon monoxide. No other sample approached this one in re- spect to the prominence of carbon monoxide, but even in this one the after damp was much diluted with air. It may be instructive to undertake a rough calculation to show approximately what proportion of after damp is really present. Assume that essentially all of the oxygen of the air in the exploded portion of the mine was con- sumed in the explosion, and that carbon monoxide was formed because of insufficient oxygen, either directly or from the reduction of carbon dioxide by the floating par- ticles of incandescent coal dust. Before making a com- putation of the proportion of after damp, it is necessary t+ decide to which of these reactions the carbon monoxide is to be assigned, as it makes a difference in the total resulting amount of carbon monoxide whether the mo- noxide be formed directly from the partial combustion of the gas or through the reduction by the glowing particles of coal dust of a portion of the carbon dioxide produced in the explosion. Beard," quoting Thomas, states that the explosion of a mixture of methane and air at the most explosive point (methane 9.57 per cent, air 90.43 per cent) produces no carbon monoxide, but that as the percentage of methane is increased above the point named carbon monoxide is formed in ever-increasing proportion until, at what he gives as the explosive limit, 16.67 per cent of methane in air, the result of an explosion would be 87 per cent monoxide and 13 per cent dioxide; while near the limit of inflammability, 29 per cent methane, no carbon dioxide * Beard, J. T., Mine gases and explosions, 1908, p. 130. 427 is formed. He writes the equation 2CH.+0.+4N.=— 2CO+-4H: + 4N:. Agreeing with this in a measure is the statement of the French fire-damp commission that the explosion of a mix- ture of methane and air, containing 12 per cent of meth- ane, gave rise to the following gases: Carbon dioxide, 4.8 per cent; carbon monoxide, 3.9 per cent; methane and other hydrocarbons, 2.5 per cent; hydrogen, 3.5 per cent; nitrogen, 82.2 per cent; total, 96.9 per cent. At variance with this, Broockmann concludes from his own experiments with the products of combustion of methane and air that a pure fire-damp explosion gives no carbon monoxide.* A mixture of air and fire damp con- of produces, along with steam, only carbon dioxide. Differ- they that the elements, carbon and hydrogen, which are combined in is 2 present for the complete oxidation of both elements. Spe SEITE Soe AEE we ag * Broockmann, Niederrheinisch-WestfiilischenSteinkohlenberg- baues, vol. 6, p. 52. * Heise and Herbst, Bergbaukunde, vol. 1, 1908, p. 448. * Idem, p. 463. 428 For the computation in the case in hand (analysis 17) it will be assumed that the carbon monoxide has not been produced directly from a partial combustion of methane and other hydrocarbon gases, but has resulted from a reduction of the carbonic acid by the particles of incan- descent coal dust, according to the reaction CO,+-C= 2CO. The analysis of the return air showed 1.07 per cent of carbon dioxide. From this are to be deducted both the percentage of carbon dioxode in the air, 0.03 per cent, for the after damp has been much diluted since the ex- plosion, and also the carbon dioxide exhaled from the coal during that time. A rough estimate of the latter can be made, as the analyses of the gas issuing from the coal in the form of feeders and blowers, as well as from coal bottled in a vacuum, show that the proportion of carbon dioxide to methane in the gas escaping from the fresh coal of these mines is 1 or 2 to 100. As the percentage of methane was found to be 2.51, the amount of carbon dioxide which the fresh coal has contributed to the air since the explosion may be taken to be 0.03 per cent. This is the proportion of carbon dioxide to methane in the gas from fresh coal. In the older workings of the mine the preportion of the dioxide is greater than this; but in the absence of data upon the ratio of these gases escaping from coal which has long been exposed to the air, no allowance is here made for the greater proportion of carbon dioxide in the old entries. This leaves 1.01 per cent of carbon dioxide to be assigned to the after damp produced by the explosion. To produce 1.01 cubic centimeters of carbon dioxide and 0.61 cubic centimeter of carbon monoxide from an explosion of methane, in cooperation with coal dust whose heated particles cause the formation of the monoxide by abstracting oxygen from a portion of the dioxide, 2.63 cubic centimeters of oxygen would be consumed, pro- viding that all the hydrogen of the methane was burned ‘oO water. 429 This computation does not take into account the fact that, in addition to methane, other hydrocarbons partici- pated in the explosion. These necessarily consisted of relatively more carbon than CH,. But, on the other hand, the coal-dust particles which caused the reduction of the dioxide to the monoxide, instead of being pure carbon, contained a certain proportion of hydrogen, a portion of which was probably oxidized to water. These two factors tend to offset each other. Because of their complexity they can not be further treated here. On the supposition that no carbon dioxide was absorbed by the water in the mine, and that all the oxygen in the air was cons.imed in the explosion, the volume of the oxides of carbon in the sample collected should bear the same relation to the amount of CO.+CO originally de- veloped by the explosion as the corresponding volume of oxygen, 2.63, does to 20.5, the percentage of oxygen which is assumed to have been originally present in the mine. This figure is taken because the coal rapidly ab- sorbs oxygen from the air. The average proportion of oxygen in the air of tight places in this mine was found by a calculation from the analyses to be only 20.08 (see p. 15); but 20.50 would seem a better figure for the average of the mine air as a whole. The ratio~3v is equal to 0.128. or from 12 to 13 per cent of after damp in the sample collected. However, this can at best be only a rough estimate, as several uncertain factors are involved. The mine air pre- vious to the explosion contained a small and unknown quantity of carbon dioxide. But on the other hand, some carbon dioxide has doubtless been absorbed by the water in the mine since the explosion. In a measure these factors tend to offset one another. It is also true that other hydrocarbons, in addition to methane, were con- sumed in the explosion, and these would unite with oxygen 430 in different proportions. But methane in all probability contributed most. While this sample of the air from the Darr mine after the explosion shows that carbon monoxide may reach a considerable percentage in after damp, the other samples of the mine air which, however, were collected after better ventilation had been established, showed the presence of much less carbon monoxide, even though the proportion of the dioxide in some samples amounted to 1 per cent. It seems probable that some and perhaps most of the difference was due to more thorough ventilation before the later samples were collected, for carbon monoxide, once removed, would not be resupplied except in very small quantities, but carbon dioxide might have been supplied from the coal, the lamps, etc., since the explosion. However, the relative proportions of carbon dioxide and carbon monoxide in after damp must always be vari- able, depending on the ratio between the available oxygen and the available combustible matter, gas and dust, in the air. If the explosion were due largely to methane in the air, in quantities not exceeding 10 per cent, and with little dust as an accessory, little carbon monoxide would be formed. But, on the other hand, in a dust ex- plosion where large quantities of coal dust are present, capable of distilling volatile hydrocarbons in volumes too great to be entirely consumed by the quantity of oxygen in the mine air, and where there is an abundance of hot coal dust stirred up in the air, carbon monoxide might, perhaps, be produced in greater quantities than the di- oxide. A coal-dust exploion is more complex than one of fire damp. If the explosion of the dust proceeds by rapidly feeding the flame with combustible gases and hydrocarbon vapors derived from it through the influence of the heat. as is believed to be the case, there is, at first, sufficient oxygen at hand to insure the complete oxidation of the gases developed. Carbon dioxide and steam result. But under ordinary conditions, with plenty of dust, the dis- tillation of volatile matter continues, liberating an excess 431 of readily available combustible gas which, because of insufficient oxygen, is only partly consumed. In the ab- sence of oxygen, a portion of the carbon dioxide already produced is reduced to carbon monoxide in variable pro- portions, depending on the amount of red-hot dust float- ing in the atmosphere and the length of time during which the dust remains sufficiently heated to allow the reducing reaction to proceed. DEFICIENCY OF OXYGEN. In order to ascertain the character of the mine air, irre- spective of the after damp, a recalculation of the analysis was made. The analyses of gas from mine feeders and from coal bottled in a vacuum show that the proportion of carbon dioxide to methane in the gas escaping from the fresh coal of these mines is 1 or 2 to 100. Wherever methane is found in the mines it is safe to assume that a volume of carbon dioxide corresponding to 1 per cent of the methane has escaped from the coal simultaneously with the marsh gas. This figure, plus the 0.03 per cent of carbon dioxide in normal air, is subtracted from the percentage of carbon dioxide in the analysis. To be on the rieht side, it is assumed that all the rest of the carbon dioxide has been produced by the oxidation of CH,, as the combustion of this compound consumes more oxygen per unit of carbon dioxide formed than anv of the other com- pounds which could have participated in the explosion. The amount of oxygen which would have been required. on the basis of an explosion of methane, to yield the oxides of carbon found in the analysis, is then added to the percentage of oxygen shown by the analysis. The percent- ave of methane in the analysis, plus the carbon dioxide of normal air and that which, on the basis of the methane present, has been considered to have been derived from the coal since the explosion, is deducted from the total, and the remaining figures recalculated so as to add to 100. 432 This gives an estimate of the percentage of oxygen in the mine air irrespective of the after damp from the ex- plosion and the feeder gas which has escaped into the workings from the coal since the explosion. Because of the assumptions, these estimates give a generous figure for the percentage of oxygen. An average of the three analyses of air from the Naomi mine made in this way was 20.86 per cent, eleven analyses from the Monongah mine gave 20.72 per cent oxygen, and thirteen analyses from the Darr mine gave an average of only 20.08 per cent oxygen. These figures indicate a deficiency of oxygen in the mine air which can not be attributed to the forma- tion of free carbon dioxide or carbon monoxide, unless it be supposed that much of the carbon dioxide formed has been absorbed by water in the mine, which seems improbable in these dry mines. Instead, it would appear that the coal has absorbed oxygen from the air, thus reducing the percentage of that gas and increasing that of nitrogen. The greatest deficiency in oxygen occurred in the sam- ple of gas-laden air collected near the face of the swamp entry in the Darr mine (analysis 25). Corrected for car- bon dioxide and methane, this sample showed the unusual proportions, oxygen 16.13 per cent and nitrogen 83.87 per cent. This sample was also characterized by the high- est proportion of methane (50.67 per cent) obtained in these mines. That the diffusion of the air and gases in this cleft in the roof had progressed slowly is shown by the accumulation of so much fire damp, and it was apparently because of the stagnancy of the air in this nook that the coal was able to abstract such a proportion of the oxygen. It must be noted that feeder gas often contains several per cent of nitrogen, so that with 50 per cent of methane (feeder gas) present in the air a part of the apparent excess of nitrogen and deficiency of oxy- gen may, perhaps, be explained by this nitrogen coming from the coal. 433 As many of the samples of air which have contributed to these averages, particularly those from the Darr mine, were collected from sheltered, poorly ventilated nooks in order to get data on the accumulation of fire damp, the low figure of 20.08 per cent for oxygen is not representa- tive for the air of the mine as a whole. While the loss of oxygen is less conspicuous in the general mine air than in pockets in the roof and in tight places where there is little air stirring, its effect is felt throughout the mine, and furnishes an additional reason for ventilation which will afford a continuous supply of good air, as well as remove the dangerous fire damp and the noxious products of combustion. POSSIBLE CONDITIONS OF GAS IN COAL. The gas which escapes from coal may exist within the mass of the coal in three possible conditions. It may be mechanically held or imprisoned in minute pores, cavities, or cracks throughout the coal; it may be occluded or dis- solved within the substance of the coal; or it may be the result of slowly operating chemical reactions, such as those which have produced the coal from the original vegetable matter and which, still operative, might, as a working hypothesis, be supposed to generate gas in pro- portion as it is given off. In the first two cases the gases are supposed to be already existent within the coal as gases; under the third hypothesis they are to be regarded as now produced for the first time by chemical decom- position of the solid coal substance. The ultimate source of the gases may be taken as the same under each hy- pothesis, for there can be little doubt that the bulk of the gas given off from coal has arisen from the slow decomposition of organic matter as a by-product in the process which has converted vegetable humus into coal. The first hypothesis favors the belief that the gas-gener- ating process has been very slow and that such gas as comes off at the present time has long been stored in minute cavities or pores, from which it escapes when the 434 coal is fractured, as in mining operations. The second hypothesis assumes, like the first, that the gas was de- veloped long ago, but differs from it in assuming that the gas, as fast as it was developed from the coaly matter, was retained within the coal substance in solution, or occluded, instead of being held mechanically in minute crevices and cracks. This hypothesis is suggested by the well-known property of various metals to occlude or dis- solve within their mass certain gases, and by the familiar power of charcoal to condense on its surface or absorb many times its own volume of various gases. The term occlusion, which Graham gave to this imperfectly under- stood property of certain metals to absorb particular gases, has been very loosely used, especially in mining literature, where “occluded gas” usually means gas held according to either of the first two hypotheses, the radical differences between them having generally been over- looked. By some writers, indeed, the term is intended to carry the idea of the first hypothesis alone, the second, that of true occlusion, being left out of account. The third idea is only a working hypothesis which is framed to recognize the possibility that the coal-forming, gas-generating process is still in progress, and that the escape of the gases is a sort of index of the present chem- ical activity within the coal. LIBERATION OF GAS BY CRUSHING COAL. PLAN OF EXPERIMENTS. To throw light on this possible threefold state in which the gases are held in coal, and to determine the relative importance of the three hypotheses, a series of experi- ments was devised. In the first the coal was broken up and crushed to a coarse powder in an air-tight receptacle, from which any gas liberated during the process of crush- ing can be extracted by a vacuum pump. Only such gas as was already stored in the coal can be freed by crush- ing it, as the process is accomplished very quickly. How much gas might be expected to be freed from a state of 435, true occlusion by crushing is less clear. The most thor- oughly studied form of occlusion is that of hydrogen by palladium. Whether palladium charged with hydrogen will give off part of its gas at the ordinary temperature when placed in a vacuum depends entirely on the condition of the metal. If the palladium is in a very finely divided state, a considerable portion of the hydrogen is given off when the pressure is greatly reduced;* but the cast or forged metal gives off no hydrogen whatever when placed in a vacuum at ordinary temperatures.’ The hydrogen begins to be evolved from the solid metal only at tempera- tures above 100°C. It is conceivable that reducing the size of coal fragments by crushing in a vacuum might, in some similar way, allow the evolution of gas which was not possible from the lump coal. But as the lumps of coal are only crushed down to a coarse powder it would not seem as if truly occluded gas should be freed, to any large extent, by the coal crusher, even in a vacuum. If crushed under full atmospheric pressure in an inert gas, no occluded gas should be liberated. It is not at all certain that coal behaves like palladium in these matters. It seems, therefore, safer to conclude that by crushing the coal and opening up many pores and cavities it is chiefly the imprisoned cavity gas that is liberated. METHOD OF CRUSHING. The apparatus for crushing the coal was constructed on the principle of the familiar steel mortar, fitted with a long piston rod incased in a heavy rubber tubing, which, with one end fastened to a flange at the top of the mortar cylinder and the other wired to the piston rod near its free end, makes an air-tight connection, and at the same time renders the piston movable. A few vigorous blows delivered with a heavy mallet upon the end of the piston rod serve to crush the coal, after which the * Moissan, Chimie minérale, vol. 5, p. 860. > Graham, Chemical and physical researches, pp. 283-290. 436 gas liberated during the crushing is pumped out of the cylinder through a short delivery tube, fitted with a stop- cock.* The apparatus is intended to maintain a complete vacuum for the short time required to crush a sample of coal, but in practice it was found advisable, in order to prevent a slight inleaking of air, to place the cylinder of the crusher in a pail of water during the operation. This crusher was able to pulverize from 50 to 100 grams of coal at a time. The coal was crushed both in a vacuum and under full barometric pressure. DETAILED RESULTS. Sample 1.—Coal collected on December 13, 1907, from the face of No. 4 right entry, off the F-face heading, mine No. 6, Monongah, was crushed in a vacuum on January 27, 1908. Starting with lumps of coal of about 1 cubic inch, the material was crushed twice, the crusher being opened after the first crushing and the finer dust sifted out. The extent to which the coal was reduced after both crushings was determined by sieves, as follows: Of 100.21 grams of coal used, 20.56 grams passed through a 30-mesh sieve, 31.26 grams passed through a 10-mesh sieve, and 48.39 grams was too coarse to pass the 10- mesh sieve. There was obtained 10.57 cubic centimeters of gas at 0° C. and 760 millimeters pressure, having the following composition: Analysis of gas obtained by crushing coal sample 1 Per cent (OEE DLE TRAE ARS A AT TNE PIE: 2.90 RR SET INCE AE SA. Ra RRL Data t Tadésotdiaatan 39.65 RR AER SRA AEE ARE ches te ln Tk 10.07 RSS ERENT HORN Rs AERC Aleve AM = 22 38.11 I CUI ais i cicen te cctvcrsiccwsaecncenibitnlnceinns — 9.27 100.00 @ This rock crusher has been described in detail, with a diagram- matic sketch in The gases in rocks: Carnegie Institution of Wash- ington, Pub. No. 106, p. 39. 437 If the gas all came from the coal which passed through the 30-mesh sieve, the methane would amount to 0.26 of the volume of that coal. The latter figure is to be preferred. Sample 2.—Coal collected December 12, 1907, from room 3 on third right, off second north heading, mine No. 8, Monongah, was crushed in a vacuum January 28, 1908. Two lumps of coal were pulverized, in two crush- ings, to the following degree of fineness: Of 49.13 grams in all 20.24 grams passed through the 30-mesh sieve, 23.67 passed through the 10-mesh sieve, and 5.22 grams was too coarse to pass the 10-mesh sieve. The crushing liberated 11.71 cubic centimeters of gas at 0° C. and 760 millimeters pressure, which had the following composition: Analysis of gas obtained by crushing coal sample 2 Per cent READE i a RR AI Ain BENE 1.56 ET Se CRE Rs 40.99 8 AGE Ry 2 RE RR a MRE a RR Re 9.86 Nitrogen................. seinliiathtnitA Seitcwadstediees kekaRoa dates 87.62 TREC a sie 10.27 100.00 The quantity of methane is equivalent to 0.30 of the coal which passed the 30-mesh sieve, to 0.14 of the volume of the 10-mesh coal, and to 0.12 of the volume of all the coal used. A duplicate test with this same sample of coal, crushed in three trials, afforded the observation that there is not any very noticeable slackening in the gas obtained from the second and third crushings. For the first trial the total weight of coal is used. After the gas has been pumped over into the receiver, the crusher is opened and the fractured coal sifted with both the 10-mesh and 30- mesh sieves. Only the coal coarser than the 10-mesh sieve is returned to the cylinder of the crusher for the second trial. The second trial thus crushes coal fragments 438 averaging about the size of a bean to fine 10-mesh coal and dust, and as it crushes about the same weight fine enough to pass through the sieves as did the first trial, it is to be expected that about the same volume of methane will be obtained. After the second trial the coal is again sifted and that portion which is too coarse to pass through the 10-mesh sieve is put back into the crusher for the third trial. It is clear that some of the gas comes from that coal which is partly crushed, though not fine enough to go through the 10-mesh sieve, but in estimating the volume of gas given off per unit volume of coal it seems advisable to consider only that coal which has passed through the sieves, for whatever gas may have come from the coarser coal would undoubtedly be offset by the gas still remaining in the fine coal. Crushing coal to 30-mesh does not remove all the gas. In the experiments with samples 1 and 2 the coal was crushed in a vacuum and the gas brought out under reduced pressure. To ascertain the part played by low pressure in this process of gas extraction, and hence whether much gas escaped from occluding bonds, samples of coal were crushed under the full barometric pressure, both in air and in an atmosphere of carbon dioxide. Sample 3.—Coal from the same can as sample 1 (p. 18) was crushed in air under full barometric pressure. As it was necessary in this experiment to discover how much methane is liberated solely by crushing the coal, without the cooperation of a reduction in pressure, the gas was removed from the crusher in two portions. The first por- tion consisted of the air and gas which was removed by the first stroke of the vacuum pump. The stopcock being open only about two seconds, and only about half the contents of the crusher being removed, whatever meth- ane was found in this portion must have been freed from the coal without the influence of reduced pressure. As soon as this portion could be stored away for analysis, Gases removed after crushing coal sample 3 in air, with their relation to the coal by volume. [Tabular Matter Omitted] As would naturally be expected, the percentage of methane is higher in the second portion than in the first, though the difference is not great. But the greater amount of methane in the second portion was not liberated entirely through the influence of reduced pressure, as the had stood longer in the second case than in first, and the element of time proves to be an im- portant factor in the escape of gas from coal. However, only the first portion is to be taken as repre- senting the gas liberated during the crushing under full atmospheric pressure. An estimate of the total volume of gas obtained from the crusher on the basis of the analy- sis of the first portion gave the first two columns of the following table. A comparison of these figures with those in the last two columns, obtained by combining the volumes of the two portions analyzed separately, may help to show how much gas may be attributed to the reduced pressure. o 2 e. é Relations to the coal by volume of gases removed after crushing coal sample 3 in air. {Tabular Matter Omitted] The confirmatory tests were made with other samples of coal from Monongah mine No. 6. Sample 4 was col- lected December 16, 1907, from the face of the east returning air way, and crushed March 10, 1908. Sample 5 was collected December 13, 1907, from the face of the Il manway, and crushed March 18, 1908. Each of these 440 samples was crushed in air under barometric pressure, and the gas removed in two portions. For each sample the total volume of methane was calculated for both portions of gas, on the basis of the analysis of the first portion, which came over with the first stroke of the pump. At least this calculated amount of methane must have come off without the aid of reduced pressure. Ex- pressed in terms of the volume of coal which was crushed down to 30-mesh, the amount for sample 4 was 0.27, and for sample 5, 0.79. The volume of methane actually obtained for the two portions was, in the same terms, 0.41 for sample 4 and 0.86 for sample 5. In the test of sample 5 the difference between the total volume of methane actually obtained and the calcu- lated volume which must certainly have been liberated from the coal under full barometric pressure is small. Moreover, only a portion of this small difference can be attributed to the effect of reduced pressure, as other factors, such as slow diffusion and the greater interval of time, have helped to cause this difference. For a series of systematic experiments to show the amount of methane which is liberated from the same coal under various conditions, the can of coal which was collected from the face of the H manway in Monongah mine No. 6 was selected (sample 5). The results of crushing lumps of this coal are as follows, the several tests being set forth in numbered paragraphs, with the volume of coal crushed to 30-mesh and to 10-mesh: 1. Coal was crushed in a vacuum, but so much water vapor was given off and drawn past the cal- cium chloride drying tube into the pump that in order to draw over all the gas it was necessary to keep the pump going for nearly one hour. Hence the time factor enters here. Ratio, by volume, of methane to 30-mesh coal, 0.88; to 10-mesh coal, 0.33. 441 2. Coal crushed in a vacuum and the gas im- mediately pumped off. Then a full atmosphere of carbon dioxide was run in and pumped out, bringing with it the last traces of methane. Two separate trials were made, giving ratios of 0.89 and 0.83, respec- tively, to 30-mesh coal, and 0.38 and 0.34 to 10- mesh coal. 3. Coal was crushed in a vacuum, but phorus pentoxide was used as a drying agent instead of calcium chloride. Ratio of methane to 30-mesh coal, 0.84; to 10-mesh, 0.33. After pumping out this gas and removing it for analysis, an atmosphere of carbon dioxide was run in as rapidly as the apparatus i 4. Coal crushed in air under barometric pressure. This test has been described on page 21 (sample 5). The amount of methane was 0.86 of the 30-mesh coal and 0.41 of the 10-mesh. methane, 0.91 of the 30-mesh coal, 4.4 of the 10- Tests 6 and 7 were made to determine the influ- ence of the length of time during which the coal is 6. Coal crushed in a vacuum and allowed to stand 3% hours with occasional pumping. Then the 442 apparatus was filled with carbon dioxide and pumped out again. Total duration of the experiment, 4 hours, considerably more gas was thus obtained than when the process was completed in less than 1 hour. An- alyzed in four separate portions. The total methane was 1.38 times the volume of 30-mesh coal, and 0.57 of the 10-mesh. 7. Coal crushed in a vacuum. Pumping kept up for 1 hour; then, after a short time, 30 cubic centi- meters of hydrogen were let in and soon pumped out. After 1% hours an atmosphere of carbon dioxide was run in and pumped out again. Duration of ex- periment, 4 hours. Analyzed in three portions. Total methane, 1.39 times the volume of 30-mesh coal, and 0.53 of the 10-mesh. These last two experiments, in which the totals include all the methane which escaped from the coal during four hours after the process of crushing, show that the gas does not all escape from the coal within the first few minutes after the coal is shattered, and that to obtain comparative results it is necessary that the time consumed during the process of removing the gas after the coal has been crushed be approximately the same in all tests. In the last test the gases pumped off during the first hour, those brought over by the hydrogen, and those which came with the carbon dioxide, were collected and analyzed separately, but nothing of significance was developed except, perhaps, the fact that the hydrogen treatment yielded somewhat less methane than had been anticipated. These experiments, taken as a whole, appear to indi- cate that, in respect to the volume of methane obtained from the coal, it makes little difference whether the coal is crushed in a complete vacuum, or under the full baro- metric pressure, in an atmosphere either of air or of carbon dioxide, provided the gas in each case is quickly pumped out of the crushing apparatus. Gas continues to 443 escape from the crushed coal at a rather rapid rate for some time after it has been crushed, but this feature will be considered elsewhere. The quantity of gas immediately liberated from the coal when it is broken up is thus largely independent of the outside pressure. Such gas, therefore, can not be sup- posed to have come directly from a state of occlusion, for, without an appreciable change either of temperature or pressure, occluded gas should not be given off in this way, even from finely divided coal. Nor can it come immediately from chemical decomposition of the nongas- eous constituents of the coal. It must, instead, have been already stored within the mass of the coal as free gas, mechanically imprisoned in numerous pores, cavities, and crevices, from which much of it is immediately released as soon as the confining walls are shattered in the process of crushing, and the pores and cavities opened to the sur- face. Necessarily, in the process of crushing to this state of fineness, only a portion of the gas-holding pores are so opened as to enable the inclosed gas to escape at once. In many others, the shattering makes it possible for the gas to escape by slow diffusion, where before it was securely held. Hence an abnormally rapid escape of gas follows for a short period of time after the coal has been crushed. However, it is not impossible that in those tests in which the coal was crushed in a vacuum or practical vacuum, the reduced pressure, acting on the fresh surfaces of the crushed coal, might have caused the escape of some truly occluded gas. If such gas escapes from the coal, it would be likely to come largely from that portion which was most finely pulverized. (See p. 17.) But quantitatively this occluded gas can not play a very important part in the gas liberated by crushing the coal, as its liberation is dependent on a reduction of pressure, and these experi- ments indicate that, in the volume of gas given off, it makes little difference whether the coal is crushed under 444 the full barometric pressure or in a complete vacuum. Thus, while there is a possibility, and even a probability, that some of the gas does come from a state of occlusion, it seems more plausible to regard the main bulk of the gas escaping from coal during the process of crushing, and an abnormal rate just after being crushed, as being cavity gas, whose escape is facilitated by the shattering which the crushed coal fragments have received. The fact that the presence of oxygen, nitrogen, hydrogen, or carbon dioxide in the crusher has little influence on the amount of methane given off during the crushing, and for a short length of time afterwards, is in harmony with the theory that this gas escapes largely from mechanical bonds. GASES FROM COAL BOTTLED IN A VACUUM. VACUUM BOTTLES. The experiments with the coal crusher have shown how much gas can be liberated from these coals by crushing them to a certain degree of fineness and opening up many of the gas-holding pores. But this process does not re- move all the gas, nor is it the only way to extract the gas from coal without the use of heat. To get the gas which slowly escapes from coal, different samples of coal were stored in vacuum bottles, from which the gas evolved was pumped out from time to time. Each of these bottles had a capacity of 500 cubic centimeters and was fitted with a one-holed rubber stopper containing a short delivery tube. Over the free end of the delivery tube was slipned a short piece of heavy antimony rubber pressure tubing, which serve to make the connection with the mercury pump. A strong screw clamp on the rubber tubing closed the way to the bottle. The stopper and rubber connec- tions were all coated with paraffin to prevent leakage of air. When the air from the bottle had been completely exhausted, the clamp upon the rubber tube was tightly screwed, the rubber tube disconnected from the pump, ' ' 445 and a plug of glass rodding quickly run into the rubber tube as far as the screw clamp would permit. Rendered tight by paraffin the bottle was submerged in a jar of water until the time came to remove the gas. At any time desired the wottle could be connected with the mer- cury pump and the gas which had accumulated removed for analysis, after which the bottle was agzin submerged in the water jar. VOLUME OF GAS. The volume of the gas extracted from coal by allowing it to remain in an essential vacuum for a period of time was somewhat variable and depended on the sample of coal, the interval of time between its removal from the coal fragmen‘«. and the duration of the experiment. The finer the coal the more rapidly and completely was the gas liberated in a given period of time. At the end of six months gas was still accumulating steadily in those bottles which contained lump coal, and it was only in those containing crushed coal that the escape of gas had nearly ceased. The volume of gas from the crushed coal ranged from 0.9 to 2.3 times that of the coal from which it came. The lump coal yielded gas to the extent of 0.5 to 0.9 of its own volume during half a year at low pres- sure. Because of the pressure of other laboratory experi- ments, and the time required for the inspection of the Darr mine shortly after the material was collected at Monongah, more than a month elapsed between the col- lection of the coal samples and the bottling of them in a vacuum. These figures, therefore, do not represent all the methane given up by the coal since its removal from the seam, for a certain quantity of the gas may be sup- posed to have escaped while the coal was in the collecting cans. To obtain data on the volume of gas lost during the first month after the removal of the coal from the seam, samples of fresh coal were collected in the usual cans, which were at once hermetically sealed with a thick coat- 446 ing of paraffin, before leaving the coal face. When opened in the laboratory about a week later, a determination of the gas in the cans was made, after which some of the coal was immediately placed in the vacuum bottles. In this way all the gas escaping from the coal after the sample was mined at the working face was determined. A specimen of bituminous coal in the form of lumps from the Mansfield mine at Carnegie, Pa., gave off 0.55 of its volume of gas, exclusive of nitrogen, during seven days in the collecting can and thirty days in the vacuum bottle. Analyses made at intervals during this length of time indicated that gas was freed much more rapidly during the first few days after collecting than later. But a similar experiment with gassy anthracite coal showed only a slight slackening in the rate of methane escape, and this change in the rate was almost uniformly dis- tributed throughout the period of observation. CHARACTER OF GAS. The coal thus bottled in a vacuum was kept under observation for a period of half a year, during which time the bottles were connected with the mercury pump at stated intervals and the gas which had accumulated was removed for analysis. Thus not only was the rate at which the gas escaped from the coal discovered, but the character of the gas evolved throughout this length of time was determined. However, as the principal ob- ject of the experiments in which these vacuum bottles were employed was to determine the volume of methane escaping from the coal during a given interval of time, léss care was given to the determination of the minor constituents, especially carbon monoxide and the ethylene series. In some tests the absorption of the olefins with fuming sulphuric acid, or bromine water, was omitted, and the gases of this series were removed, together with carbon monoxide, by cuprous chloride. Also, the leakage of small quantities of air into the vacuum bottles was not prejudicial to the chief purpose of the experiments, for 447 the volume of methane was in no way affected. Although these analyses are subject to these limitations, they yet serve to indicate pretty closely the general character of the gas which escaped from the coal during the period of half a year under reduced pressure. Four of these sets of analyses of the gas from coals are given in the table following. Analyses of gases escaping from small lump coal bottled in a vacuum, with relation to the coal by volume [Tabular Matter Omitted] The analyses of the gas from the other samples of Carboniferous coal which were subjected to this same treatment show similar results.° The most noteworthy change in the nature of the gas escaping from the coal during the period of observation was the steady decrease in the proportion of nitrogen and the corresponding in- crease in the percentage of methane. Much of the nitrogen that appeared in the portion of gas removed from the bottles at the end of the first three weeks doubt- less came from air which adhered to the coal or was ab- sorbed by its mass, and was not given off immediately when the vacuum was produced. As the oxygen which coal absorbs enters rapidly into chemical union with the substance of the coal, the latter respires chiefly nitrogen (with some carbon dioxide) in place of the air taken in. The influence of the nitrogen from the air is naturally most felt during the early part of the sojourn of the coal in the vacuum bottles, as this nitrogen is largely held by the surface layers or in the more prominent crevices and lines of fracture. It therefore escapes from the coal more readily than the gas originating in the coal, which is distributed throughout its mass, but most abundantly in *The Cretaceous coal from New Mexico, however, behaved dif- ferently (giving 30 to 40 per cent carbon dioxide and only 4 per cent methane), but that is outside the field of this report. 448 the interior of the fragments, from which escape is slow and difficult. As this extraneous nitrogen was removed, the percentage of the methane rose proportionately. Methane was quantitatively by far the most important gas which escaped from the bottled coal. After the ex- traneous nitrogen had been removed, it ran in some tests as high as 98 per cent of all the gas coming from the coal. More commonly, however, it constituted from 80 to 95 per cent of the gas liberated. Methane reached its highest percentage in the gas from anthracite coal, which yielded only small proportions of the other constituents, carbon dioxide and nitrogen. In addition to methane, at least one other higher mem- ber of the paraffin series was found. In nearly every analysis the explosion of the residual gas with oxygen, after the removal of the absorbable gases, produced car- bon dioxide in slight excess over what would have re- sulted from the combustion of methane alone. Calcula- tions show that the excess of carbon dioxide noted can be explained by the presence of ethane in proportions of a trace to 4 parts of C:H. to 100 parts of CH. Other higher paraffins may be present in small quantities, but the computations are made on the basis of ethane alone, as C-H.++CH. = 2C-H.. So far as the tests have been carried, the bituminous coal has yielded more ethane than the anthracite (one sample only). In fact, in several tests the explosion of anthracite gas, instead of indicating higher paraffins, suggested the presence of a small amount of hydrogen. Carbon dioxide was found to be a more variable con- stituent of the gas, depending on the nature of the coal from which it came. The various experiments with the Monongah coal show that in most of the samples it amounted to 1 to 3 per cent of the gas which accumu- lated in the bottles. In the bituminous coal from the Mansfield mine at Carnegie, Pa., carbonic anhydride be- came much more important, reaching 13 per cent of the 449 total gas given off. But on the other hand, careful analyses made over mercury failed to detect any carbon dioxide in two out of the four portions of gas from the anthracite coal of Nanticoke, while the analyses of the other two portions revealed the presence of only small quantities of this gas. Although the proportion of meth- ane steadily increased as the experiment progressed, in general the proportion of carbon dioxide fluctuated dur- ing the period of observation. The volume of nitrogen in the bottles fell rapidly dur- ing the progress of these experiments. Apparently much of the nitrogen which was obtained from coal by this and other methods, especially that portion of the gas which came off most readily, is not to be regarded as gas held by the coal while in the undisturbed strata, but as nitrogen absorbed by the coal after it became exposed to the air in the mining operations. Some of it was derived from air adhering to the coal and tubes in spite of the effort of the mercury pump to remove it. The leakage of air into the bottles could take place only while they were out of the water jar and connected with the pump. Hence, most of whatever inleaking air there may have been was quickly pumped over into the gas receiver with the rest of the gas, and was determined in the analysis on the basis of the amount of oxygen found. Only such air as could leak into the bottle, between the closing of the screw clamp and the immersion of the bottle in the water jar after sealing the rubber-tube connection with glass plug and paraffin coating, could remain in the bottle with the coal during the interval between tests. Absorp- tion of oxygen from such air by the coal would leave an excess of nitrogen in the gas. But as less than one min- ute elapsed between the closing of the screw clamp and the immersion of the bottle, the amount of leakage was reduced to a small figure. The excess of nitrogen in the analyses of the portions of gas taken at the end of the half-year period indicated that the cvai did contain nitrogen as a truly original gas. This may have come originally in pat from air buried with the accumulated 450 vegetable matter and in part from the decomposition of nitrogenous compounds in the organic matter whose metamorphism produced the coal. The minor constituents of the gas from coal were car- bon monoxide and one or more members of the olefin series, most probably ethylene. The above figures represent the character of the gas escaping from lumps of coal averaging somewhat less than a cubic inch in size. The evolution of gas had in no case ceased at the end of the six-months period. Instead, gas was still steadily accumulating in the bottles, though at a diminishing rate. The composition of the last por- tion of the gas which would eventually escape, if the experiment were carried on for a much longer period, can only be inferred from these experiments with the lump coal. However, from the studies on the finely crushed coal, from which the gas escaped much more rapidly and completely in a given length of time than from the coarser fragments used in the above tests, more can be learned on this question. Two representative ex- periments with coal crushed in the rock crusher so as to pass through a 10-mesh sieve, and then bottled in a vacuum, may be selected to illustrate the composition of the gas which came from the coal after the main bulk of the free gas had been liberated and the outflow had nearly ceased. Analysis of gases escaping from crushed coal bottled in a vacuum, with relation to the coal by volume.’ [Tabular Matter Omitted] According to the foregoing table the relative propor- tion of both carbon dioxide and carbon monoxide in- «Coal from the face of H manway in Monongah mine No. 6, crushed so as to pass through a 10-mesh sieve, and then quickly placed in the vacuum bottle. The rate of methane liberation is shown by curve 7 of fig. 1. 451 creased greatly during the last weeks of each experiment, chiefly in consequence of the rapid slackening in the out- put of methane This gas, because it diffuses and transpires at move rapid rates than the other gases men- tioned, escaped from the coal sooner than the less active molecules, and hence the stored-up supply of free methane in the coal was more quickly depleted than that of carbon dioxide. Thus, on theoretical grounds, the coal may be expected to give off carbon dioxide for a longer period than methane. But these tables not only indicate an in- crease in the relative proportion of carbon dioxide and carbon monoxide during the latter part of the experi- ment, but they appear to show also an absolute increase in the volume of the oxides of carbon evolved per unit of time. During the first few weeks after the coal was bottled in a vacuum there was a reduction in the rate of outflow of all the gases, but during the last ten weeks of the last-year period the evolution of the oxides of carbon apparently proceeded at an accelerated rate. This feature was most conspicuous in experiments E and F, but the same phenomenon was also shown, though in a less striking manner, in the results of the two other simi- lar series of analyses which furnished the data for curves 4 and 8 of figure 1. The experiments with the rock crusher indicate that a large part of the free gas held by coal is mechanically imprisoned, under pressure, within the pores, interstices, and lines of fracture of the coal. Such gas is released immediately when the coal is pulverized and many of the gas-holding cavities are broken open. Many of the pores charged with gas are not opened by the crushing process, so that much cavity gas still remains in the crushed coal. Of the gas exhaled when the coal is placed in a vacuum, it seems safe to assign the bulk of the methane, carbon dioxide, and other gases which escape from the coal, rapidly at first, but at a progressively declining rate, to this mode of occurrence. The gases under pressure in the interstices of the coal are supposed to reach the sur- face by diffusion, or more strictly, transpiration, and to 452 escape until in time the gas thus mechanically held has bled itself out. The curves showing the rate of escape of methane support this view in regard to that gas. But the behavior of carbon dioxide and carbon monoxide in this respect appears to be different. The declining vol- umes of these gases during the first few weeks are natural enough, as the cavity gas comes off in greatest volume immediately after the coal is crushed. But reasons for the apparently increasingly volumes toward the end of the experiments are less easily found. Possibly the increment of carbon dioxide and carbon monoxide may come from a state of occlusion. (Charcoal, which is like coal, is known to absorb the gxides of carbon in much greater volume than hydrogen 4 and probably also in greater vol- ume than methane, though the figures for the latter are not at hand. The presumption, therefore, is that of the coal gases the oxides of carbon are likely to be held in greatest volume as occluded gas. But why such gas, even if occluded, should be liberated most rapidly after so long an interval is not apparent at the present time. Perhaps the explanation is to be found in chemical changes. For the present, however, the cause of this phenomenon must be left open. Further experimentation, to determine how generally the rule is true of different coals, is necessary before more is made of this point. COMPARIS WITH MINE GASES To make a comparison between the composition of the gas which escapes from the bottled coal in the laboratory, and that which issues from the rock strata, a few analyses of feeder gas from the mines may be introduced: Analyses of feeder gas. [Tabular Matter Omitted] The presence of a higher member of the methane series, probably ethane, was noted in Nos. 1, 3, and 4, but the « Moissan, Chimie minérale, vol. 2, pp. 251-253. 453 paraffins have here been computed as so much methan In No. 5, after the removal of the hydrogen by palladium, the explosion indicated only methane. A comparison of the foregoing table with that on 26, after the proper allowance is made for air and ine gen absorbed from the air by the coal used in the labora- tory experiments, fails to show any significant difference between the feeder gas encountered in the mines and the gas extracted from lumps of coal in the laboratory by means of a vacuum. But a comparison with the table on page 29 shows that, while the feeder gas bears a close resemblance to the gas which is obtained from the finely crushed coal during the first few weeks under reduced pressure, it is quite different from the gas which is finally exhaled from the fine coal after it has stood some months and has lost the bulk of its free gas. The feeder gas does not contain the high percentages of carbon dioxide and carben monoxide which characterize the last gas to escape from the fine coal. Feeder gas therefore represents that portion of the gas which is first to escape from the coal and which comes out most readily. It would seem to be that portion of the gas which, having been mechanically held at the outset in the interstitial spaces throughout the mass of the coal stratum, has subsequently escaped from the scattered pores in the coal and has accumulated along more or less connected lines of fracture, or other places of weakness or increased porosity. Traveling along these, it now issues into the mine workings from distinct ori- fices, cracks, or localized portions of the coal bed, at a more rapid rate and in greater volume than it i : tye phar it is elsewhere ee. the ae of » in the form of feeders, » Must die out long before the steady ex- aaa me Ges Body of the coal, oles int cued oe fracture continue to serve as paths of discharge for the gases slowly but steadily gathering in the porous reser- voirs back in the coal. And to judge from the slowness with which even small lumps of coal manifest a change in the character of the gas transpiring from them, even 454 when favored by a reduction of pressure, it would seem that a very much longer period of time would be required to produce the change in composition which the behavior of the finely crushed coal suggests will ultimately occur in the gas freed from the solid coal. But in the case of pillars and other coal surfaces long exposed to the the weathering action of the mine air, there enters another factor which is absent in the vacuum- bottle experiments—-that is, the steady oxidation of the coal by the oxygen of the air. Experiments on coal bot- tled in air, under ordinary barometric pressure, show that oxygen is rapidly absorbed by the coal until, after a few days, there remains often only | or 2 per cent of oxygen in the free gas in the bottle. At the same time a certain proportion of the oxygen uniting with the coal comes off again as carbon dioxide, but this, at least during the short time of the experiment, amounts to only a small part of the oxygen entering the coal. Perhaps with an abundance of air and a much longer period of time, so as to allow the coal to absorb oxygen to its full capacity, a much larger proportion of it might eventually reappear from the saturated hydrocarbon compounds, as carbon dioxide. The feeder gas originates back in the coal seam, away from the influence of the air, and hence it does not con- tain carbon dioxide from the direct oxidation of the coal. But the exposed coal surface must produce carbon dioxide in this way and thus supply the mine air with carbonic acid, which, though coming from the coal, is largely inde- pendent of the free gas content of the coal. This property appears to vary in different coals. The gassiness of a certain coal is not necessarily an index to the volume of carbon dioxide which may be developed from it as a contribution to the mine air. A few analyses made in Germany of the air from unexploded mines indicate a higher proportion of carbon dioxide, in comparison with methane, than is found in the feeder gas, suggesting that the oxidation of the coal may be a more prolific source of 455 the carbon dioxide encountered in the mines than the out- flow of the free gas stored within the coal. we RATE OF ESCAPE The samples of coal were kept in the vacuum fi twenty-six weeks, or just half a year. At an pox vals d this time the gas which had accumulated was pumped out and analyzed. As methane was by far most abundant gas thus obtained, as well as the most important from the standpoint of this investigation, the volumes of that gas given off per unit volume of coal were taken a ine Standard. Curves were plotted, as in figure 1, to now the rate of escape of this gas from the coal, the or- cnethane. ane Sraph representing the relative volumes of methane, absci i a : Ssas expressing the progress of Descriptions of the es of coal iti from which the iia adiies were «ens oo Curve. 1. Methane from coal collected from the face of the fourth right entry, off the F face heading, in mine No. 6, at Monongah, December 13, 1907: bottled in vacuum January 23, 1908. ‘eet Curve 2. Same coal as No. 1. Crushed in vacuum on January 27 by means of coal crusher placed in the vacuum bottle. lies Curve 3. Methane from coal collected from room 3 on third right off second north heading, in mine No. 8, Monongah, December 12, 1907: bottled in vacuum January 23, 1908. Curve 4. Same coal as No. 3. Crushed in v in coal crusher January 28, and then placed in the vacuum bottle. Coal passed through 30-mesh sieve. Curve 5 Coal from the face of the east return air way in mine No. 8, Monongah. Collected December 17, 1907; bottled in vacuum February 10, 1908. 456 Curve 6. Coal from face of right main, Naomi mine. This is the most gassy point seen in the mine. Collected December 14, 1907; bottled February 11, 1908. Curve 7. Coal from face of H manway, mine No. 6, Monongah. Collected December 13, 1907; crushed in vacuum March 17, 1908, and immediately placed in vacuum bottle. Curve 8. Same coal as No. 7. Crushed in air under fuli barometric pressure on March 18, 1908, and immediately placed in vacuum bottle. Curves 1, 3, 5, and 6 show the escape of methane from lumps of coal averaging approximately the size of a marble. Curves 2, 4, 7, and 8 indicate the vol- ume of gas which escaped from coal crushed so that all of it would pass through a 10-mesh sieve, a con- siderable part of it being necessarily much more finely reduced than this. 457 a (eed ‘3x09 008 uoryeunid xo 307) -Te0o tos oCEAIIUT Jo edeose jo sozes Supmogs MBSE —T THAI z % a 4 st gt ow a ot g +] ? t Q ' = 4 . i 4 — ome T an po ‘ sen ’ ee ak — . — sn ma : ba : = « ON OF > = ; . = sone ; . = TTT — @ ‘ ' " ‘e+ hall i | . : > r —- " i i i = on OT re i C/)) * Sm r i ; ; L ’ " he TTT Tia | Lik Trt : ¢ i mom ame ee ee : =. yy we ee : ee eee «eee : i = Eze />) ee astm -f kA ' az ; i) jenbeabndenienianl oF” ; " Pa eee «Saas ' i a : i ‘Ange ae : = a i +} u ps i 9 ~ ge if tt ts 4 et eee i ‘4 i; ! i. yume i a n" a. ‘i : : = ii i LB rei t oN = 1! . oe = . ‘ i Ah teeta sh : . ce - iat sitet > i . =z ert i tis ' «£ = i eRTRB = Tho? | : st L =e ce eee eA pag EY ‘4 = < . es waeee See ee 1 9 ON BL a a 7 'f } , Lisa . - ’ i : * : : ew — wr 2 - se — a ul . om 4 LON SS : “Tt = a at = : i con i im rae sit = ° 7 ‘ i : - ee! ' i La! eboeat de atoll 3 }. 8 Lt ' mm: | : = oe be 4 7 am. i i if me tT ’ ; ot = | : =) : i | i) ss | ft si a= 4s ‘ ; ‘ — =e ,) 1: I panes p+ i 4 yet - “a 4 rt 2 r “TT a om i " : we (ame. er : ) ++ zt , se : i - = Me, ’ ' i : ) i im om me — ry i , ‘ : et : ia vt . Saeeer,s sneees &. gt ut cj ' et 8 ON cet! Li met 459 The volumes of methane liberated during the process of crushing are also included in these curves. Hence curves for the crushed coal instead of commencing at the zero point start at points on the vertical axis corresponding to the volume of methane lost during the process of crush- ing. The four curves representing the lump coal show that the escape of methane from fragments of coal, even in a vacuum, takes place slowly and steadily and must in some cases continue for a very long period of time. Curve | is nearly a straight line, showing that the evolu- tion of methane was nearly as rapid at the end of twenty weeks as when the coal was first placed in the vacuum. In the other three experiments the rate of escape declined more rapidly. The relation between the size of the coal fragments and the rate of gas escape is strikingly shown by com- paring the curves obtained from the crushed coals with those representing the same coals in lumps. Curves 1 and 2 were parallel experiments with the same coal, as were also curves 3 and 4. The finely~crushed coals gave out methane at a very rapid rate for a short time after being bottled, but the rate soon rapidly declined. In the experi- ments represented by curves 7 and 8 the escape was ex- ceedingly rapid during the first week after the crushing, but had greatly slackened before the end of the second week. Bottles 2 and 4 were not opened until the end of the sixth week, so that these two curves are not so sharply bent. It is clear from these experiments that the gas escapes more readily, and at first in greater volume, from the fine coal than from the coarser lumps, but that the supply of free gas held by the fine coal is more quickly depleted, while the loss from the lump coal is more uniform. After a time, therefore, the coarse coal gives off gas more rap- idly than the fine. The graph shows that the curves for the same sample of coal approach each other and will 460 in ti bly at a point rently come together in time, proba wre es uP ch ee hausted. It seems probable, q ralieg Bye Mice the coal, whether finely divided or in t howe aan lumps, has little influence on the total amo “ pene to in a sufficiently long period of —, yer hayes makes a very great difference in the rate a say oe gas is given off. The phenomenon —— ot Aagg one involving the quantity of gas stored wi sg Se which can escape, and not one of gas generatio the interval of time. i f Some of the results of these experiments on the Ben i escape of gas from Monongah coal may be sum in the following generalizations: 1. Reduction of pressure removes the gases from coal slowly—a matter of weeks and months. 2. Finely powdered, fresh coal ag off pangs sang ing Si i than the same during six months in a vacuum oe oal subjected to the same con IS. 4 an during a much longer period of time — mately the same volume of gas should be expecte come off from either type of coal. 3. Reduction of pressure, acting for only a few See or even a few days, is far less effective in extracting entrapped gas than crushing the coal, either in a vacuum or under barometric pressure. 4. Crushing coal to a certain degree of agers aig approximately the same volume of methane whet —— operation is performed in a vacuum or In an atmosp of air or carbon dioxide. i f fineness of which 5. Crushing the coal to the degree of fir i the crusher tanith removes only a minor ee of the free gas stored within the coal. For 0 gy i um or un 1 already crushed, either in vacuui : pre see pressure, will yield more methane during 461 the next two weeks in a vacuum than was liberated dur- ing a process of crushing. PRACTICAL SIGNIFICANCE OF RATE. The escape of methane, which takes place slowly and steadily, even from small lump coal, and at a rate that is much influenced by the size of the coal, must continue very steadily for long veriods of time from the solid coal in the mines. This means that throughout every portion of a mine, in the old workings as well as the new except in the portion of the seam near the surface from which the gas has been slowly escaping during long geologic ages), a steady outbreathing of methane gas is to be expected. This may be independent of recognizable “feed- ers” and “blowers” and may come from the massive coal, as well as from distinct cracks and fissures leading back to storage reservoirs. But because this gas escapes as slowly as it does steadily, it does not often become dangerous in mines where the ventilation is good; but old, abandoned workings, cut off from the rest of the mine and from the ventilation, soon fill with methane from this continual exhalation of gas. A much greater danger lies in those more rapid out- bursts of fire damp which unexpectedly flow into the new workings when a strong blower or reservoir of gas is en- countered. Necessarily the quantity of gas suddenly forced into the workings must vary within extremely wide limits, depending on the nature and extent of what may, for convenience, be termed the storage reservoir. These so- called reservoirs of gas are, in reality, porous portions of the coal seam or adjacent strata, or a series of fissures, in which the gas has accumulated and is now stored, at many places under very great pressure. When a crack or fissure leading back to a region of stored gas is encoun- tered in mining operations, an outflow of gas into the working results. Suc ten falls of rock from the roof often open avenues of esuape for pent-up gas. When lines of 462 communication with extensive reservoirs of stored gas are opened, large quantities of fire damp may flow into a portion of the mine in a short time and thus render the air in this part of the mine explosive. These lines of com- munication may be opened either in the ordinary mining operations or because of the formation of new lines of fracture accompanying the natural deformation move- ments of the strata. Settling of the overhead beds, to- gether with a general redistribution of the strains caused by the removal of the coal, is likely to open new sets of fissures and seal old ones. Hence there may be periods of more gas and periods of less gas, depending on the local movements of the strata and the effect of such move- ments, by opening or closing fissures, on the facility with which the pent-up gases can find lines of egress. No ap- peal, however, is here made to seismic or volcanic dis- turbances in other parts of the world, whose influence on the local conditions must be trivial. From these experiments it has seemed safe to conclude that the solid coal in the seam must continue to supply methane for long periods of time. This means that as the supply of gas collected in reservoirs is reduced by escape into the mine, the adjacent coal has a tendency to yield gas to replace that which is lost, until (in case the avenue of escape is cut off by movements of the strata or other causes) a state of approximate equilibrium is established between the gas distributed throughout the mass of the coal itself and that accumulating in the so-called reser- voirs. If a reservoir of gas were tapped by boring and the gas removed, the reservoir would, in the course of time, be likely to become recharged, partly at least, with more gas supplied by the adjacent coal, provided the avenue of escape became closed. Just how rapidly a de- pleted reservoir might be resupplied with gas, and what bearing this factor has on practical mining, must be left an open question for the present. 463 EFFECT OF BAROMETRIC CHANGES. When the lumps of coal were placed in the vacuum bottles and the air was exhausted by means of the mer- cury pump, it was found that the reduction of the pressure to a fraction of a millimeter caused the immediate escape of only a small quantity of methane. The exhaust air from the bottles of Monongah coal contained methane in vol- umes ranging up to 0.002 of the volume of the coal. Lumps of coal from the Naomi mine and the Mansfield mine at Carnegie, Pa., added similarly small volumes of methane to the exhaust air. Three samples of coal from the mine at Cardiff, Ill., gave only traces of methane, but a fourth, from a gassy portion of the mine, gave off 0.003 of its volume of methane. A bottle of anthracite coal from No. 1 north shaft of the Susquehanna Coal Company at Nanticoke, Pa., gave off methane to the ex- tent of 0.03 of the volume of the coal while the air was being pumped out of the bottle. The time required to remove the air from these bottles was about twenty min- utes. Thus a sudden drop of 740 to 750 millimeters in pressure within twenty minutes does not bring out a very large volume of gas. Experiments already described have shown that time is required to bring out the gas, even in a vacuum. To discover how much more gas is given off from coal under low pressure than under the full barometric pres- sure, 20 pieces of bituminous coal from the Mansfield mine at Carnegie, Pa., were placed in a vacuum bottle and the air exhausted. At the same time 21 chunks of similar size, taken from the same collecting can, were placed in a bottle filled with air. The two bottles were then submerged side by side in a water jar. At the end of ten days the gas which had accumulated in the interval was pumped out and analyzed. The coal which had been bottled in a vacuum was found to have given up 0.25 of its volume of methane, while methane amounting to 0.14 of the volume of the coal had accumulated in the bottle 464 that had been filled with air. A similar experiment with two bottles of anthracite coal from Nanticoke, Pa., showed, after an interval of one week, exactly the same relative volume of methane in each bottle—1.07 times the volume of the coal. As in each experiment the volume of methane liberated was greater than the volume of oxy- gen which the coal absorbed from the air, the final pres- sure in the air-filled bottles was greater than the baro- metric pressure. Low pressure aided the escape of gas from the bitumi- nous coal. but it appears to have had little influence on the liberation of gas from this sample of anthracite coal. That identical volumes of methane should have escaped from the anthracite coal under such widely different pres- sures is perhaps to be regarded as largely a coincidence, for the distribution of gas is not uniform throughout the coal: but with about 20 fragments of the coal in each bottle, the gas content of the coal in one bottle should not differ greatly from that in the other. It is to be noted that, while the total pressure in each of these air experi- ments was very different from that in the parallel vacuum experiment. the partial pressure due to methane alone started at zero in each bottle and at the conclusion of the experiment with the anthracite coal had become as great in one bottle as in the other. Tp considering the influence of barometric fluctuations on the volume of gas exhaled by the coal in the mines, however, it is the total gas pres- sure which is of significance, rather than the partial pres- sure due to methane. It would seem therefore that even the greatest fluctua- tions of the barometer, which do not exceed 40 millimeters, can not have very great influence on the volume of gas escaping from the interstices of the coal itself. But in the case of feeders and blowers, in which the gas escapes for the most part directly from accumulations stored within more or less connected systems of fissures and zones of fracture, instead of from minute pores in the coal, the 465 . effect of the diminution of pressure probably is more marked. This should be particularly true wherever the stored gas is under only a moderate pressure and the path- way of escape into the mine workings is readily followed; the strong blowers coming from the reservoirs far back in the coal, where the gas is held under high pressure and communication with the coal surface is more difficult, are necessarily much less affected by the relatively slight barometric changes. Heise and Herbst bring out the point that, although frequent measurements have shown that the gas stored up in the fresh, undisturbed coal often is under pressure amounting to several atmospheres, these high pressures are obtained only by boring several meters back into the coal; and that close to the coal face the gas is under a pressure but slightly in excess of the barometric pressure." Blower gas, in that portion of its course which is near the orifice, is under only a slight pressure, so that an increase in the barometric pressure adds resistance to its outflow, causing it to slacken, whereas with a falling barometer the outflow of gas must become more active. In this way the common observation that the outflow of gas from blowers increases with a falling barometer and slackens percep- tibly with a rising barometer is shown to be entirely con- sistent with the high gas pressures that have been found to exist in the undisturbed coal some distance from the exposed face. _ The influence of barometric changes on the outflow of air and gas into the active workings from old abandoned entries which are not completely walled off from the rest of the mine is well known and does not fall within the scope of this discussion. * Heise and Herbst, Bergbaukunde, vol. 1, 1908, pp. 458-461. 466 GASES OBTAINED BY HEATING COAL. Meyer,” Thomas,° Bedson,* Trobridge,” and other inves- tigators have extracted gases from coal with the aid of heat, by warming the coal generally up to the boiling point of water, and in some experiments as high as 200° C. In many tests the higher members of the paraffin series, such as ethane, propane, and butane, were obtained in considerable proportions. At least one gas of the olefin series was often present in notable quantities. The present analyses of feeder gas from the mines and of the gas which slowly escaped from the coal bottled in a vacuum, as well as of that liberated directly by crushing the coal in the rock crusher, do not reveal the presence of any such high proportions of the heavier hydrocarbons. But these gases were all extracted at ordinary tempera- tures. As the constituents of coal include various hydro- carbon compounds, some of which may be supposed to be partly decomposed or volatilized at even moderate temperature, there comes to mind the suggestion that a portion of the olefins and higher paraffin gases obtained from these European coals, instead of existing within the coal in the free state, may have been produced from chem- ical decomposition induced by the heat employed. To test this possibility, parallel experiments were undertaken. A can of fresh bituminous coal from the Pittsburg district being selected for this test, one portion of the coal was stored for thirty days in a vacuum bottle; a second portion was pulverized on an anvil so as to pass through a 10- mesh screen, and then quickly placed in a suitable glass tube connected with the mercury pump, and the air re- > Von Meyer, Ernst, Jour. Chem. Soc., vol. 25, 1872, pp. 798-801. ¢ Thomas, J. W., Jour. Chem. Soc., vol. 28, 1875. pp. 793-822, and vol. 30, 1876, pp. 144-152. * Bedson, P. Phillips, and McConnell, W., Trans. Fed. Inst. Min. Eng., vol. 3, 1892, pp. 307-310; vol. 7, 1894, pp. 27-53. * Trobridge, F. G., Jour. Soc. Chem Ind., vol. 25, 1906, p. 1129. 467 moved. This tube was then kept for three hours succes- sively at 50° (water bath), 100° (boiling water), 150° (oil bath), and 200° (metal bath). The gas obtained during three hours at each temperature was collected and analyzed. The same experiment was then repeated with anthracite coal from the vicinity of Scranton, Pa. The results, expressed in volume of each gas relative to the volume of the coal as unity, are given in the following Analyses of gases obtained from coal in a vacuum at different temperatures. [Tabular Matter Omitted] The other portions of these two coals were kept in vacuum bottles at low pressures for thirty days. At inter- vals during this period the gas which had accumulated was pumped out and analyzed, in order to furnish additional data on the rate of methane liberation (see pp. 33-36). The gas was pumped from the bottle containing the bitu- minous coal at the end of each ten days; from the anthra- cite at the end of each week, except that the fourth period was extended to nine days to complete the full thirty days. The following table indicates the character of the last Portion of the gas obtained from these two vacuum bottles: 468 Analyses of gases given off by coal during last 10 of 30 days in a vacuum. {Tabular Matter Omitted] Ethane ..as present in the gas from the anthracite coal, if at all, only in small quantities. In two of the four analyses made of the gas from this coal the result of the explosion determinations indicated a small amount of hydrogen instead of higher paraffins. The explosions in the other two analyses pointed to the presence of a small proportion of ethane accompanying the methane. A comparison of the three tables shows that for these two coals the gas extracted by heating the material up to 200° C. is somewhat, though not radically, different from that which slowly exudes from the coal when bottled for a period at ordinary temperatures. The heat caused the expulsion of such uncombined gas as was ready to escape at ordinary temperatures, and in addition developed some new gas from the nongaseous constituents of the coal. Most conspicuous among these new products were the vapors of hydrocarbons which at ordinary temperatures are normally liquids. Benzene was probably the most prominent of these vapors. The hydrocarbon vapors be- gan to appear in notable quantities at 100° and increased in importance as the temperature was elevated. The vol- ume of ethane also rose slowly with the increase of heat, suggesting that some of this gas did not come from a state of mechanical imprisonment in the pores of the coal, but was produced by chemical action induced by the heat. Gases of the ethylene series remained unimportant, even up to 300°, in the experiments with the anthracite coal. The high proportions of higher hydrocarbon gases ob- tained by Meyer, Thomas, and Bedson by heating Ger- man and English coals up to 200° were not found in the gas from these two samples of Pennsylvania coal. By heating dust from the Darr mine up to 350°, however, 469 both olefins and higher paraffins, which at lower tempera- tures had appeared only in moderate quantities, were made important constituents of the gas evolved. (See tables on pp. 57-58.) Such gases could have come only from chemical action or from a state of true occlusion, for they must inevitably have been liberated in consider- able volume at the lower temperatures as well had their liberation been merely a question of escape from the inter- stices of the coal. Substantiating this view in a measure is the testimony afforded by the vacuum bottles. These experiments show, at least as regards the coals used in these investigations, that the gas slowly coming off from the crushed coal at the end of a period of six months at very low pressures is not notably richer in the higher members of the marsh-gas series than the gas rapidly ex- haled at the beginning of the experiments. These higher hydrocarbons do not diffuse and transpire so rapidly as methane, but if they were present in any considerable volume, mechanically held within the pores of the coal, as is the methane, a period of six months would seem sufficient to permit their escape in notable proportions. 470 SURVEY PUBLICATIONS ON FUEL TESTING AND MINE ACCIDENTS. The following public [Text truncated at 120,000 characters. The full text is on the page linked above.] --- Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/brief%3Amicro_IA40385014_0245%3A14. Public record. Not legal advice.