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By N. P. Kripakov

The Bureau of Mines has developed a unique new mine design procedure to determine the changing static load distributions imposed on under-ground support structures during the mining cycle. The procedure reduces the complexities associated with analyzing a three-dimensional problem. A combination of the multiple-seam displacement-discontinuity model and a two-dimensional finite-element window model produces refined results for a specific area of interest by assuming displacement compat-ibility between models. Input to the procedure includes the geometry of mined-out areas in up to two adjacent seams, the rock mass characteris-tics of the surrounding geology, the in situ stress conditions, and the mining sequence. The displacement-discontinuity program calculates ex-pected loadings for mine structures affected by the mining cycle and/or by overlying or underlying seams. Pseudoelastic finite-element analysis using a yield-factor approach determines the stability of coal pillars by simulating the degree and extent of nrogressive rib failure and sub-sequent load transfer. Application of the procedure is demonstrated on a field problem. In-duced stress changes predicted from the numerical model analysis are in reasonably good agreement with stress measurements obtained from an instrumented chain pillar affected by remnant workings in an upper seam.

Jan 1, 1988

By G. K. Derby

The Bureau of Mines investigated methods for removing dragline bucket wire rope terminations with the objective of finding efficient methods that are safer than the method most commonly used at U.S. surface mines, which is to use the explosive impact of a projectile fired from a cannon to remove the rope termination. Removal of a wire rope termination for repair or replacement requires separation of the wedge and socket that lock together to secure the rope end. The Bureau investigated currently used methods and improved upon and tested two safer alternate methods for removing wire rope terminations. A cannon test program was conducted, using 40-and 50-gr primer (detonating) cord, to establish the possible force produced with a 4-in-bore cannon and a 55-lb projectile. Wedge and socket units supplied from cooperating mines were separated under controlled conditions to establish data on separation force requirements. The two alternate methods investigated were use of the force generated by (1) a pendulum ram and by (2) a portable hydraulic pusher. Both methods are capable of providing sufficient force to effect wedge and socket separations on draglines with up to 78-yd3 buckets under normal conditions.

Jan 1, 1984

By McClelland. John J.

This Bureau of Mines report discusses recent applications of water in-fusion technology to control dust in U.S coal mines and presents recommended guidelines for determining coal seam infusibility. The techniques required to use water infusion are presented in detail. A Bureau case study indicated that water infusion reduced dust levels by 68 pct along a longwall plow face, bringing this section into compliance with the Z.0-mg/m3 Federal dust standard. Similar studies conducted by Occidental Research Corp. under a Bureau contract show water infusion at two longwall double-drum shearer operations produced dust reductions ranging from 38 to 50 pct. Water infusion was found to be cost effective, aver-aging 5 cents per ton.

Jan 1, 1987

By Albert L. Toenges

This paper is the third of a series4/ that describes some methods and practices of mining coal mechanically where operations are conducted on more than one shift. The mining of coal by means of mechanical devices has emphasized the need for continued study of the relationship, of these devices to existing physical conditions and to planning of the operations for increased safety and economy. The purpose of this investigation is to stud the operations of different types of mechanization used in mines under various systems of mining and physical conditions to reach conclusions as to the safest and most economical methods and practices of mining. Physical conditions very in different and in the same mining districts and determine, together with economical conditions, the systems of mining and the types of mechanical loading equipment used. The information presented in this paper

Jan 1, 1941

By K. C. Dean

Fine-sized mineral wastes discarded by ore milling plants require stabilization to prevent air and water pollution. Stabilization has been attained by physical, chemical, vegetative, and combination procedures. Vegetative reclamation is preferred to physical and chemical stabilization but is diffi¬cult to achieve because the wastes are sterile, contain deleterious inorganic salts, and lack the essential nutrients and physical characteristics required for sustaining vegetative growth. Methods now have been developed for attain¬ing vegetative growth on all but excessively acidic, basic, or saline tailings at costs ranging from $120 to $650 per acre. The cost for stabilizing tail¬ings requiring more intensive treatment techniques may range upward to $1,750 per acre. This report summarizes procedures developed by the Bureau of Mines and industry for vegetating amenable tailings, lists costs for the various processes, and suggests procedures that may be applicable for stabilizing saline and pyrite-containing tailings. Ridged planting beds, drip irrigation, and deep-furrow planting techniques are suggested for stabilizing saline wastes. A combination of mill tailings and sewage sludge can be used for pro¬ducing synthetic soils, and layers of sewage sludge buried under a layer of tailings offer promise of inhibiting acid formation from oxidation of sulfides in mineral wastes.

Jan 1, 1974

By H. M. Thorne

The Union of South Africa has been interested in oil shale for a long time, and deposits of oil shales, torbanites, and similar rocks have been found in many parts of the country. (Fig. 1.) Samples differ markedly in oil yield and in the characteristics of the oil. The strata vary in thickness, and most of the deposits that have been found are in unfavorable locations because of remoteness from markets or absence of transportation facilities. This report deals mainly with the torbanite deposit near Ermelo, Transvaal, in the Union of South Africa, and the operations of the South African Torbanite Mining and Refining Co., Ltd. (hereafter referred to as Satmar), in mining the torbanite, retorting it, and refining the crude oil.

Jan 1, 1954

By R. J. Fantel

The Bureau of Mines investigated the resources, costs, capacities, market relationships, and short- and long-run supply of phosphate rock and phosphoric acid. The 206 mines and deposits evaluated in 30 market economy countries contain an estimated 35.1 billion mt of recoverable phosphate rock (demonstrated resource level). U.S. resources are sufficient to satisfy the domestic and export markets for phosphate products well beyond the year 2000. Because of resource depletion at current producers, however, new properties (with higher cost levels) need to be developed if U.S. production levels are to be maintained. Existing worldwide capacity can satisfy expected demand through the early 1990's. Expansion at existing mines or low demand growth could mean that no new property development will be needed before the late 1990's. Worldwide, almost $8 billion could be required for development of new phosphate rock properties between now and the year 2000, given 3-pct annual growth in demand. Most properties that could develop in the 1990's would require price increases of 20 to 50 pct to break even. To earn a 15-pct rate of return on investment, prices must rise to nearly double the present level of $24 to $29 per metric ton.

Jan 1, 1988

By W. R. Gilliland, G. W. Jones

"One-phase of the accident prevention program of the Bureau of Mines is the determination of the explosion hazards of various combustible gases and vapors encountered,mining and allied industries and the development of means and methods of eliminating them.Gasoline is foremost among the combustible-liquid's as to quantity used and variety of applications in industry, It is a chief contributor to the causes of fires and explosions, taking an enormous yearly toll in property damage and considerable loss of lives.The results presented in this report evaluate the effect of various gaseous inert substances, which owing to their chemical composition, should be of considerable value in the prevention of gasoline fires and explosions. The substances investigated are as follows: Nitrogen (N2), automobile exhaust gas (85 percent N2 + 15 percent CO2), carbon dioxide(CO2), dichlorodifluoromethane (CCl2F2-Freon-12), trichloremenofluoromethane (CC13F-Freon-11), and dichloromonofluoromethane (CHCl2F-Freon-21).The general term ""gasoline"" designates a combustible liquid of such characteristics as to give satisfactory operation without preheating in spark-ignition-type internal-combustion engine. It comprises a complex hydrocarbon mixture having a limiting distillation range and produced commercially by distilling or ""cracking"" crude petroleum or other various petroleum stocks. Small proportions of other substances may be incorporated in the gasoline to enhance its antiknock properties or operating characteristics in internal-combustion engines and to increase its stability during storage, transportation, and use.It is thus seen that gasoline may have rather wide variations of chemical and physical properties, and it would: appear that the results of any investigation dealing with one particular gasoline might not be applicable to other types. However, as indicated by the results given in this report, the inflammable properties of different gasolines at normal atmospheric temperatures are influenced largely the mars volatile hydrocarbons containing 5, 6, 7 carbon atoms- in the molecule, and that the heavier constituent of higher molecular weight have a minor influence on the inflammable properties at ordinary temperatures."

Apr 1, 1946

By R. G. Meara, O&apos

[P.F? bmit e-ninirq ir.3.l r;tq: in the Znited State :; was u~irlyortant p~ior to the Torld ;Jar, ?-.lt with the c~r,sxti~rl of imports d11rln.c thr World 'Jar tke Rmericnn mar~factu~er:. of 1itkopone mcl Sayiun c;~oai?als forced tile tl~veloor?.ent of domertic bar,i$e dqosit9. Pr%~~,n-ily bcca-lse of tho increasing dc.n;;nl'i for lit,hupone3 by the pr?i:~t, Tlocr-covcrin~;, ,md rt1tbe.r indl~stries, ~3c.vs1o~:rnc2t of cto~entic de~onits has cr~ntim~ed to c-cpand. 13 1914, the salnr! oC doxegtic c~l~.dt? t,m-it~ ;u~cr-~nteii. to 52,91? tons, in 1237 ???,1!.1 tons nmre so1.d; thc 12:t~r rcyrprcntcd 77 .E;T pmccnt of the tot,:rl, dr??;ectic and imortcd., haritd US~C in the Cnited State? di7rinz t,hat :.vXr. C,f +he total 193,3:& ton? coy.1~-ed in the United 4 Steter ir. 135, 3E.X percent v;as usec? as groi.z.ld ~rai.te? , "0.3 percent arr lithopone, and 17 .:A ].ercc?t in the rnx 11fact,ure of b;~riim chs:nicals . ]

Jan 1, 1938

By D. P. Schlick

The German experience in dealing with the health hazard of respirable dust in underground mines is reported from first-hand observation in this Bureau of Mines paper. The report covers-- 1. The control of dust by water infusion, water spraying, and ventilation. 2. The sampling devices (tyndalloscope , konimeter , and BAT-I) and methods used to determine the dust concentrations in mines. 3. The systems of classifying hazardous and safe dust levels in mines. 4. The research facilities devoted to theoretical and applied work on mine dust and pneumoconiotic disease. Tile major research projects on dust and disease now underway in West Germany are outlined in an appendix.

Jan 1, 1970

By R. G. Meara, O&apos

[P.F? bmit e-ninirq ir.3.l r;tq: in the Znited State :; was u~irlyortant p~ior to the Torld ;Jar, ?-.lt with the c~r,sxti~rl of imports d11rln.c thr World 'Jar tke Rmericnn mar~factu~er:. of 1itkopone mcl Sayiun c;~oai?als forced tile tl~veloor?.ent of domertic bar,i$e dqosit9. Pr%~~,n-ily bcca-lse of tho increasing dc.n;;nl'i for lit,hupone3 by the pr?i:~t, Tlocr-covcrin~;, ,md rt1tbe.r indl~stries, ~3c.vs1o~:rnc2t of cto~entic de~onits has cr~ntim~ed to c-cpand. 13 1914, the salnr! oC doxegtic c~l~.dt? t,m-it~ ;u~cr-~nteii. to 52,91? tons, in 1237 ???,1!.1 tons nmre so1.d; thc 12:t~r rcyrprcntcd 77 .E;T pmccnt of the tot,:rl, dr??;ectic and imortcd., haritd US~C in the Cnited State? di7rinz t,hat :.vXr. C,f +he total 193,3:& ton? coy.1~-ed in the United 4 Steter ir. 135, 3E.X percent v;as usec? as groi.z.ld ~rai.te? , "0.3 percent arr lithopone, and 17 .:A ].ercc?t in the rnx 11fact,ure of b;~riim chs:nicals ]

Jan 1, 1938

By W. H. Tomlinson

One of the more important functions of the Federal Bureau of Mines is conservation of the life and health of employees of the mineral and allied industries. Since its very beginning the Bureau has encouraged competition between mine rescue and first-aid teams as a means of stimulating interest in safety and accident-prevention work. In addition to sponsoring competition on a national and international scale during the past 45 years, the Bureau has also assisted State mining departments, mining companies, and mining organizations in holding State, district, company, and other local meets. This assistance includes providing instructors to train teams, judges, and other contest officials. The Bureau has also furnished problems and outlines for working them, judges I discount sheets (scorecards), contest rules, and problem judges. In fact, Bureau representatives participate in nearly all State, district, and company contests and have bad complete charge of some contests.

Jan 1, 1956

By J. D. Davis

The Bureau of Mines Coal Carbonization Laboratory has been interested for the past 20 years in the quality of coke in connection with the selection of coals for the manufacture of coke. The principal experimental. method of carbonization, whereby 100- to 200-pound charges are carbonized in sheet-steel cylindrical retorts with recovery and determination of the properties of coke, gas, and products, was developed in cooperation with the American Gas Association,4 5 and it is known as the BM-AGA method. Results of the investigations of 90 coals included in the BM-AGA Survey of the Carbonizing Prop¬erties of American Coals have been published; 6 and, in addition to these, about 200 coals have been carbonized over limited temperature ranges. Because coke from cylindrical retorts differs in shape from that made in rectangular ovens, the BM-AGA method has been criticized, although those who developed it have always believed that it served well as a means of measuring the relative strengths of cokes from different coals. It is recognized that no laboratory-method carbonization, even on a large twit, can yield results that exactly duplicate those obtained in commercial ovens and retorts. However, with the completion and satisfactory performance of an experimental vertical slot oven of 500-pound capacity at the University of Illinois Geological Survey Laboratory,' the opportunity to directly compare BM-AGA coke with coke made by two-sided heating became available and the necessary test apparatus was installed. The Bureau of Mines slot oven, which is similar to that designed by the University of Illinois Geological Survey, has been used to carbonize 11 coals (or blends) tested by the BM-AGA method. This report compares the results obtained by the two methods.

Jan 1, 1950

By J. Dean Warner

Alaska contains many critical and strategic minerals that are scarce in the conterminous United States. Among these are tin, tantalum, and columbium. This Bureau of Mines report summarizes available data on the production, reserves, and occurrences of these minerals in Alaska. Alaska produces about 200,000 lb of tin per year, with historical production since 1901 estimated to have totaled 5,830,600 lb. Measured, indicated, and inferred tin reserves total over 140,000,000 Ib. Much of the tin production has been from the placer mines of the western Seward Peninsula; however, most of the reserves are in that area's lode deposits. Alaskan tin occurrences are part of a belt of tin mineralization that extends along the western coast of North and South America. The Alaskan portion of this "tin belt" comprises placer occurrences and lode occurrences of five major types: greisen, vein, skarn, pegmatite, and volcanogenic massive sulfide. Greisen and vein occurrences are the most abundant, but skarn deposits have historically been the most economically important. Columbium and tantalum have not been produced in Alaska; however, they may be recoverable as byproducts of tin, tungsten, gold, or uranium mining. Approximately 135,000 Ib of columbium oxide (Cb205) are inferred within the Tofty placer deposits in the Manley Hot Springs district.

Jan 1, 1985

By C. H. Fisher

[Mxny methnhs of ,analyzing tpr oils fnr thoir tar acid ~nd base cnntent hava boon employL~d in connection mith both ac~d,.mic and. industrial investigs- tions. Mnst of thznu nnalyticel proc?durn~s aro bpsed nn th; diminution in volums caused by extract lon sit5 alkali 5 minL+ra,l acids (cantrsction rn,>thod) , although othrr mr~thrids havu &apos;sL<on ?q~lnglt 8 . In many instmccs th-: donti ti on of RT~ m~lytic~l m ithod was not ;r.:c ~d~d by ~d.jqunt9 study, and, ns 3 cone+ qucnce, tha lit .,ratur ? on thls sub,jr:.ct is consoScuous for its cnntr~dictnry . claims and rocnmmondatinna.. 1.t tiR.s b9~n shoyn in th;, cnsn of c.lrtn.in synth?tic solut innsfi/ thnt larg~ jr-orn sny rcsult if th2 ,mnlysis is c~rri~d out by sim~la extraction wi.th alidi r.nd min 3rd ncids.]

Jan 1, 1937

By C. O. Hawk

Distillable oils derived from coal were desulfurized and hydrogenated at 2,500 psig in a two-step vapor-phase catalytic operation to give a product rich in saturated cyclic hydrocarbons. The first step was mainly a desulfurization at 400 C, the second a saturation at 300 C. One of the oils used as feed stock was from low-temperature carbonization of a bituminous coal, the other was from the liquid-phase hydrogenation of coal in the Bureau&apos;s pilot plant. The product from the saturation step was distilled to remove the light ends and high-boiling residue and to recover a fraction having acceptable properties with respect to heating value, density, freezing point, viscosity, and boiling range according to specifications suggested by the Air Force for ultra-high-speed aircraft fuel. Quantities of the fuel fraction available were too small for the thermal stability test approved by the Air Force. The experiments, performed on laboratory scale, comprised mostly a study of the effect of varying the oil feed rate (at constant oil-to-hydrogen ratio) on the yield of the desired fuel fraction. The yield of the fuel fraction made from low-temperature carbonization oil was a little more than 1 percent of the weight of coal carbonized; that from coal-hydrogenation oil was about 12 percent of the weight of coal hydrogenated. A few attempts to do both desulfurization and saturation in one operation with sulfur resistant catalysts, developed for vapor-phase hydrogenation or hydroforming, were unsuccessful. By leaving the low-boiling ends in both feed stocks to desulfurization, another product was obtained: a low-sulfur aromatic cut boiling below 200 C. This material would be suitable as a solvent or a chemical raw material.

Jan 1, 1965

By G. B. Gait

This report is the third in a series concerning the Bureau of Mines program for microfilming maps of abandoned mines in the Pennsylvania anthracite region; a catalog of the microfilmed maps of mines in the Lackawanna Basin of tile Northern anthracite field is presented. Previous reports IC 8274, published in 1965, and IC 8379, published in 1968, were catalogs of microfilmed maps of mines in the Eastern Middle anthracite field and Wyoming Basin, Northern anthracite field, respectively , Additional catalogs will be published as the microfilming of significant mining areas is completed.

Jan 1, 1970

By R. R. Lowery

An analysis of three 1-1/4-diam manufactured wire ropes of 6x19 classification was done to identify and describe reference conditions of new rope. Reference condition is of value when examining tested or retired ropes. Measurements of strand and rope pitch and of wire and rope diameter confirmed adherence of all ropes to those construction specifications. Mechanical properties of strength and ductility were determined by accepted methods for the ropes and wires from the ropes. Individual wires from one rope failed to meet minimum wire ductility values. Wire chemical composition varied in average carbon levels, from 0.70 to 0.78 wt pct, and in manganese content, from 0.45 to 0.80 wt pct. One manufacturer&apos;s product contained 1 to 3 wt pct Ni and Cr. Heavily wrought pearlitic steel microstructures were porous and contained inclusions. Cold work variations were evidenced by wrought grain width. Recorded anomalies reflected the condition of the manu-factured products. The report provides data that compare the three wire ropes studied, but cannot verify the effects that these conditions or anomalies have on rope service life.

Jan 1, 1983

By Lyman Moore

This Bureau of Mines report describes 2nd evaluates iron ore resources in California and Nevada and analyzes the California and Japanese iron ore markets in which these resources will be used. The competitive position of California-Nevada ores, in these markets, was estimated by comparing regional iron ore prices, production costs, and transportation costs with those of foreign suppliers. Resources were determined to be sufficient to produce the equivalent of 585 million tons of 64-percent iron pellets at a price of less than $15 per ton delivered at California ports. Much higher tonnage could be produced at higher prices. Iron ore requirement of the California iron and steel industry will increase to an estimated 15.9 million tons by the year 2000. A study of the iron ore production potential of California-Nevada deposits and of out-of- State sources indicated that this ore requirement can be supplied most economically by California-Nevada ores. Iron ore import requirements of the Japanese iron and steel industry will increase to an estimated 150.0 million tons by the year 2000. A study of price trends in this market indicated that very little California-Nevada iron ore will be sold in Japan after 1973 when existing sales contracts expire. Iron ore-exports might be economically possible if ore could be transported from California to Japan at ballast rates as backhaul on existing petroleum shipping.

Jan 1, 1971

By Edward W. Parsons

To determine in what part and to what extent creep or movement exists in an installed rock-bolt anchor and the effect of the creep or bleedoff on the tension load on a rock bolt, as well as the effect of normal mining activity on the rock-bolt load and anchor, the Bureau of Mines conducted tests in the laboratory and in two mines using four types of expansion-shell anchors, the wedge bolt, and in one mine, explosive-anchored rock bolts. Specially mounted heavy-duty springs, calibrated to obtain load readings from spring movement, were installed on the test bolts to prevent a drastic reduction in tension load caused by slipping or seating of the anchor. A dial gage, reading to 0.0001 inch, measured movement of the anchor shell against the rock and seating of the anchor wedge plug in the shell. While all bolts had electrical resistance strain gages for load reading, only readings from the laboratory tests were used because those from the field tests were erratic. The tests revealed that most load loss resulting from static loading is due to the slippage and seating of the serrations on the anchor shell into the drill-hole wall. Dynamic loading, primarily from sudden shocks from nearby blasting, and possibly from ground movement or mining activity, will cause the anchor wedge plug to seat in the anchor shell.

Jan 1, 1969