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By Rolland L. Blake

Petrographic methods of examination were used by the Bureau of Mines on a suite of samples of ultramafic rock from Soapstone Ridge, Ga., located about 8 miles south-southeast of Atlanta. The samples were analyzed to determine (1) their potential for releasing regulatory particles upon crushing and grinding and (2) their concentration of fibrous particles that approach the dimensions of amphibole and serpentine asbestos minerals. Such particles might be generated during grading and excavation for housing and industrial development and could become a health concern. Light optical microscopy, scanning electron microscopy, and X-ray diffraction were the techniques used to examine the samples. Six of the twelve samples contained amphibole as a major mineral; in five, it was a moderate to minor mineral. One sample contained no amphiboles, and serpentine was not observed or identified by X-ray diffraction in any of the samples. In nine of the samples, the amphiboles exhibited a habit that was either prismatic or acicular, but not asbestiform. Two of the samples did contain asbestos, occurring as small veins or fracture fillings, which represented only a minor percentage of the total sample. Similar petrographic screening is recommended for examining any rock deposit or mine location to delineate hazardous and nonhazardous mineral areas.

Jan 1, 1982

By J. A. Cavallaro

This Bureau of Mines report describes the preparation characteristics of 10 coal samples collected from the significant coal-producing mines of Lucas, Mahaska, Marion, Monroe, and Wapello Counties in Iowa, with special emphasis on physical desulfurization. All 10 samples were of high sulfur content as received, ranging from 4.2 to 10.4 percent; the organic sulfur content ranged from 0.8 to 3.8 percent. The pyritic sulfur content of the samples could be appreciably reduced by crushing and washing and provided pyritic sulfur reductions ranging from 36 to 75 percent. Crushing to 3/8-inch top size and removing the sink 1.60 specific gravity material would provide float coal products containing 3.5 to 6.0 percent sulfur. However, these coals could be burned at utility plants utilizing SO2 removal processes with efficiencies ranging from 70 to 88 percent and still be in compliance with the current Federal SO2 emission regulations for stationary sources.

Jan 1, 1973

By M. D. Carver

This investigation was undertaken by the Bureau of Nines to determine the effects of impurity levels on the mechanical properties of columbium at low temperatures. High-purity, electron-bombardment-melted columbium was purchased and used as a basis material. Variations in impurity levels were obtained by arc-melting charges containing definite amounts of added impurities. Tensile tests were conducted at low temperatures. Results showed the almost pure basis metal to be ductile at minus 194° C., the lower limit of the range used, Ductility of less pure columbium appeared to depend on interstitial element content. The ductile-to-brittle transition temperature appeared to be raised by increasing carbon content in the range of 50 to 730 parts per million, nitrogen content in the range of 50 to 200 parts per million, or total interstitial element content in the range of 240 to 1,380 parts per million. Some evidence was obtained indicating that decreasing cold work also raised the transition temperature, but recrystallization appeared to have no effect on it. Variations in interstitial element levels appeared to have little or no effect on ultimate strength of columbim in the range of room temperature to minus 194° C, Physical metallurgy studies of massive arc-melted and electron-bombardment- melted columbium were included in the columbium-tantalum research work assigned to the Albany Metallurgy Research Center in fiscal year 1959.

Jan 1, 1961

1. In 2003, a total of 1,972 coal mining operations reported employment to the Mine Safety and Health Administration (MSHA). Coal mines comprised 13.7% of all mining operations. • Bituminous mines comprised 92.5% (n = 1,825) and anthracite mines 7.5% (n = 147) of coal mining operations. • More than 70% of all coal mines were located in three states: Kentucky (29.0%), West Virginia (20.9%), and Pennsylvania (20.2%). • Bituminous coal mines reported the production of over 1 billion coal tons.

Feb 1, 2005

By B. E. Davis

Over 80 pct of domestic phosphate rock, which is the starting material for phosphorus-containing fertilizers, comes from central Florida deposits. As K-her grade deposits are depleted, lower grade phosphate ores containing 'Mg0 in the form of dolomite are encountered. Treating high MgO ores with present beneficiation technology will not yield a concentrate meeting specifications for acidulation. The Bureau of Mines conducted research on three high-MgO phosphate samples from south Florida. The sales contained, in percent, 5.4 to 10.2 P205, 1.9 to 7.6 MgO, and 35.3 to 60.1 acid insolubles. A technique of sizing, grinding, desliming, scrubbing, and redesliming was used to produce a feed suitable for continuous flotation studies, A conventional fatty acid-fuel oil rougher flotation followed by two to three cleaner stages resulted in concentrates containing, in percent, 30.7 to 31.3 P205, 0.6 to 1.3 MgO, and 2.5 to 4.8 acid insolubles. The P205 recovery from the flotation feed ranged from 55.1 to 89.7 pct.

Jan 1, 1984

By W. J. Fene, J. J. Forbes

Through education, investigations, and studies and an expanded coal- mino inspection program the Bureau continued to dischargo the responsibility placed on it by Congress 39 years ago for promoting safety and health in the mineral industries. Although much still remains to be dono, definite progress was made in combating physical and psychological hazards in mines and plants. Accident-prevention cours os for coal-mine supervisory officials and special courses for coal-mine safety committeeman were inaugurated. First- aid, mine rescue, and other safety training was conducted for those engaged in all branches of the mineral industries. Assistance was given in recovery work after mine explosions and fires. Studies to reduce the danger of roof falls, the greatest single cause of fatal mine accidents, resulted in the development and adoption of new coal-mine roof-support techniques. Knowledge of the explosion and health hazards of mine and plant dusts and ways of pre-. venting them were advanced. Electrical equipment was tested for safety of operation in gassy coal mines, and emergency mine communications apparatus was developed and tested. More progress was made in the study of controlling flood waters that threaten life and property in the Pennsylvania anthracite region. More coal-mine inspections were made than in any previous year, and an impressive number of improvements resulted from the Federal inspectors' recommendations, even though many of them went unheeded. A program of con- trolling fires in inactive coal deposits on the public domain and private property was instituted during the year.

Apr 1, 1950

By Frank E. Cash

Although during the past 10 years Alabama has attained an enviable position by its coal-mine accident experience and, like most of the other coal-mining States, has made progress in the safer operation of coal mines, there is still room for improvement, which can be realized only by still greater efforts on the part of employees and employers. From 1993, when accidents were first recorded by the Alabama State Mine Inspection Department, to 1934, inclusive, 3,451 men lost their lives in the production of 569,722,676 tons of coal. The primary purpose of this report is to bring to the attention of the mining industry in Alabama end elsewhere statistics of fatal accidents for 1931-34, with the hope that a study of the causes may lead to reduction of similar accidents in the future.

Jan 1, 1936

By Thomas C. Atchison

The purpose of this Bureau of Mines investigation was to measure the amplitude and shape of the strain pulse and the size of the crushed zone produced in a granite by different explosives and to determine how these quantities are related to the detonation properties of the explosives. The reflection theory of rock breakage has shown that the amplitude and shape of the strain pulse incident at a free surface determine the fragmentation and volume of rock broken. Determination of the properties of an explosive that control the characteristics of the strain pulse produced in the rock will help in evaluating explosives for use in blasting. The investigation showed the different explosives produced a twofold variation in the amplitude of the strain pulse but little variation in the shape of the pulse. The explosives also produced a twofold variation in the volume of the crushed zone, but differences among the explosives were more accurately determined by strain-amplitude measurements than by crushed-zone measurements. The peak amplitude of the strain pulse and the volume of the crushed zone correlated with the calculated detonation pressure of the explosive.

Jan 1, 1959

By L. E. Dalverny

This Bureau of Mines report describes the deployment, 5-month operation, and lessons gained from a continuous gas monitoring system using sampling-tube bundles at an underground mine fire in West Virginia. Research information gained indicates the utility of relating certain gas concentration ratios to events during fire development, mine reventilation, and mine recovery. In addition to monitoring the quality of remote fly ash seals, the system provided timely warning of dangerous gas concentrations which developed during surface and underground recovery activities. An evaluation of system components is supplemented by recommendations for improvements.

Jan 1, 1975

By J. D. Ramsdell

The object of this investigation by the Federal Bureau of Mines was to evaluate the workability, recrystallization characteristics, and mechanical and physical properties of high-purity electrorefined vanadium. The low level of interstitially soluble elements in electrorefined vanadium results in a soft ductile metal which responds readily to cold working by rolling, swaging, and press-forging. Hardness, strength, and resistivity increased with an increase in impurity content, but thermal expansion was independent of impurity content. The work-hardening of vanadium occurs rapidly. Most of the hardness increase occurs in the first 15 pct. of reduction in area. When vanadium is annealed, its hardness increases to a maximum when the annealing temperature is between 200° to 400° C. A sharp decrease in hardness develops as the annealing temperature is increased. An anomaly in the hardness versus annealing temperature curve is present in the 600° to 800° C. range, while all evidence of cold-work is removed at annealing temperatures above 900° C.

Jan 1, 1961

By G. W. Jones, F. E. Scott

"INTRODUCTION During the last war, considerable attention was given to the search for materials or combinations of materials for use as expelling agents for aerosols in the well-known ""aerosol bomb."" These materials must be free of fire and explosion hazards under normal conditions of use.In cooperation with the Department of Agriculture and other Federal agencies interested in the work, the Bureau of Mines carried out a laboratory investigation on the inflammability of- dimethyl ether-dichlorodifluoromethane air mixtures. 4/The method of investigation was essentially the same as that used in a similar investigation dealing with the inflammability of propane-butane-dichlorodifluoromethane mixtures. 4/SOURCE OF MATERIALSThe dichlorodifluoromethane (commonly known as freon-12) and the dimethyl ether were supplied by Dr. Lyle D. Goodhue., U. S. Department of Agriculture, Beltsville, Md. It was reported that the freon-12 was manufactured by the Kinetic Chemical Co. Wilmington, Del., and the dimethyl ether by the Carbide & Carbon Chemicals Corp., Charleston, W. Va..The materials were obtained in small metal cylinders and were used as received. Before using, the cylinders mere placed in an upright position, and 5 to 6 liters of the gas was released from each cylinder to the atmosphere to remove any trapped air that may have been introduced when the cylinders were filled."

Sep 1, 1947

By Seth T. Reese

THE INJURY and related employment experience of the coking industry in the United States for 1953 contained in this bulletin are presented under three general sections, as follows: (A) General injury experience: Tables 1 to 9: Contain current and comparable statistics on operating data, number, frequency, and severity of injuries, and major accident agencies involved in the cause of injuries. Data are tabulated for the industry as a whole, for each type of oven, and for the States in which coke is manufactured. (B) Selected injury experience: Tables 10 to 15: Contain comparable injury data covering 5- and 10-year periods on the number and severity of injuries and major accident agencies. (C) Historic injury experience: Tables 1.6 to 19: Contain data on the number and rates of injury occurrence and related employment statistics on the industry from the earliest records through 1953.

Jan 1, 1955

By Arthur E. Bruszak, Marcel Vanpée

In many practical combustion systems ignition may occur through contact with hot burned gases . Such a process plays a vital role in flame stabilization on bluff bodies . It is also of importance in the ignition of firedamp by the hot spent gases of explosives used in mines . Also , in the communication of flames through narrow channels , a problem of practical importance in flameproofing electrical equipment , the propagation of the flame is essentially a reignition process in which hot burned gases are the agent of ignition . In the actual ignition problem a great variety of conditions may be visualized . Ignition may occur where pockets of hot gases are surrounded by cold explosive mixtures or where pockets of cold mixture may be surrounded by hot gases . Alternately , a flowing stream of combustible mixture may be initially in contact with another stream of hot combustion products , or a jet of hot gases may flow into a cold quiescent mixture ; the jet may be laminar or turbulent , continuous or discontinuous . The hot gas may also consist of the oxidant ( air for instance ) and the cold combustible pure fuel . This study by the Bureau of Mines is concerned only with ignition produced by a continuous jet of gas ( hot ) flowing into a practically quiescent cold mix- The investigation of ignition by bursts of hot gases or by turbulent jets is outside the scope of this report , and work performed on this phase of the problem has been published elsewhere

Jan 1, 1963

By C. L. Brown

The frequency of mine fires during recent years, with an apparent increase in recent months, has focused attention on the necessity of reducing this hazard by every means possible. Investigation reports are available on 51 mine fires of electrical origin between August 15, 1949, and August 16, 1954. Nine other fires in the same period were suspected as being of electrical origin. Every mine fire is a potential hazard to underground workmen; it is remarkable that only six lives were lost as a result of these fires, since the injury list was very high. Modern mining methods, with increased power demands and extended distribution systems underground, involve greater electrical hazards and possibilities of costly production delays as a result of inadequate electrical service. Improvements in electric-power-distribution facilities in many underground coal mines is desirable. The purpose of this paper is to show the need for this improvement as revealed by studies and investigations of electric-power-distribution systems representative of those in a large number of coal mines.

Jan 1, 1955

By Victor E. Kral

"SUMMARYFollowing a magnetometer survey on the McCoy iron deposit, a trenching and drilling program was carried out by the Bureau of Mines in August 1944.This deposit is 32.3 miles southwest of Battle Mountain in the McCoy Mining District, Lander County, Nevada, and lies on the east flank of the Fish Creek Mountains at an altitude of 5,400 feet, about 1 1/2 miles south of the gold camp of McCoy.Total production from the deposit has been 400 tons of magnetite, mined by hand and shipped to the west coast for ship's ballast.Bureau drilled two holes to a total depth of 92 feet and excavated 12 feet of trenches. Both holes were drilled in the same ore body and engineered magnetite ore 14 and 11 feet thick. Trenching was used successfully to show the lateral limits of the ore.Magnetite ore bodies were found to occur as replacements of a limestone bed in quartzite. They outcrop near and parallel to the exposure of a diorite entrusting that forms a long westward-trending ridge. Although magnetic outcrops can be traced for 5,000 feet trenching definitely proved the ore bodies to be disconnected to have little or no lateral extent beyond their outcrops. Only two ore bodies more than 10 feet thick were found; one of these is the inaccessible to and the other was drilled by the Bureau."

Jan 1, 1947

This is the initial issue of STATE MINERAL SUMMARIES. This publication provides estimated data and summaries of mineral activities at the State level for 1988. Most of the estimates are based on nine months data. These summaries have been prepared in cooperation with State geological surveys or related agencies. Individual State summaries are published separately as State Mineral Industry Surveys and copies can be obtained from the appropriate State Activities field office.

Jan 1, 1989

By M. M. Wong

A brief investigation was made to determine the feasibility of electro-refining beryllium in a KCI-LiCI-BeC12 bath. Thin, platelike crystals of beryllium metal were produced by electrolyzing technical-grade beryllium metal beads (about 94-percent purity) as the soluble anode. Operating cell conditions were: Temperatures of 450° to 600° C.; an inert atmosphere; bath compositions of (1) 38.1 mol. percent KC1, 54.8 mol. percent LiCl, and 7.1 mol. percent BeC12 and (2) 36.7 mol. percent KC1, 52.7 mol. percent LiCl, and 10.6 mol. percent BeC12; cell voltages of 0.30 to 0.80; and initial cathode current densities of 50 to 435 a./sq, ft. Current efficiencies ranging from 87 to 96 percent were obtained. Qualitative spectrographic analyses of the metal products indicated that impurities were reduced. This technique offers the possibility of producing a grade of beryllium purer than that now generally available, which may have better mechanical properties.

Jan 1, 1960

By R. L. Rough, W. K. Overbey

The Bureau of Mines obtained samples of oil - reservoir rock from wells in Ohio , Pennsylvania , and West Virginia as part of an investigation of the susceptibility of petroleum reservoirs to secondary - recovery techniques . Illustrations and tables showing the geographic and stratigraphic sequence of the cored reservoirs and 40 tables of detailed lithologic descriptions of the reservoirs are presented . Information relevant to geologic surroundings , oilfield history , coring and well logging operations , and reservoir core analyses are referenced throughout the report .

Jun 1, 1970

By Horace C. Porter, F. K. OVITZ

Much has been written of the changes undergone by coal in storage and the deterioration of coal through exposure to the weather. In order to obtain definite information for the benefit of the Government departments and of all who store coal in large quantitieS', a series . of tests was begun in the fall of 1909 under the supervision of tT. A. Holmes, then chief technologist of the United States Geological Survey, and was continued by the Bureau of Mines after its establishment in 1910. The tests were confined to determinations of the loss in heating value of the coals and did not include a study of other deterioration; for exaIp.ple, in coking quality or the yield of by-products in coking. The Bureau of Yards and Docks of the Navy Department cooperated in tests of New R~ver (W. Va.) coal, a variety largely used by the Navy. A preliminary report presenting a brief account of the early results of these tests has been published by the Bureau of Mines as Technical Paper 16.a The detailed report is presented in this bulletin, which gives a fu11 account of the tests and the analytical data covering a period of five years' storage. Data of somewhat similar experiments for shorter periods with gas coal from the Pittsburgh bed, with Pocahontas coal on the Isthmus of Panama, and with Sheridan, Wyo., subbituminous coal, which is used for railroad and other purposes in the West, are included. The tests of New River coal, in cooperation with the Navy Department, were undertaken to determine the advantage to be gained by storing coal under water, and particularly under salt water. Small lots were used in order to make the tests of maximum severity, and parallel experiments were made with run-of-mine and crushed coal under one-fourth inch size. All of the small lots tested under the different conditions (except those tested near Key West, Fla.) were taken as representative portions from one large original lot. The tests of Pocahontas coal, which, like the New River, is semibituminous, were undertaken chiefly to determine th.e effect of the tropical conditions in Panama. They were made on an outdoor pile of 100 tons of run-of-mine coal. Pittsburgh gas coal, a high-volatile, bituminous type used at gas and by-product coke works, was exposed for test at Ann Arbor, Mich., in cooperation with the University of Michigan. The university agreed to make tests at successive intervals of storage to determine, in its illuminating-gas experiment station, the yields of gas and byproducts from the coal. The coal, screened lump, was stored in about 4-ton lots out of doors in open bins. Subbituminous coal, which is mined in Colorado, Wyoming, and other States, and is known also as "black lignite," is commonly supposed to deteriorate rapidly in storage, especially by "slacking" or crumbling of the lumps. The tests herein described were undertaken at Sheridan, Wyo., in cooperation with the Chicago, Burlington & Quincy Railroad Co., in order to determine the extent of this slacking and the accompanying loss of heat value. The tests were in open bins holding 4 to 12 tons.

Jan 1, 1917

By William H. Pomroy

This report describes Bureau of Mines research that led to the design, prototype fabrication, and successful proof-of-concept testing of an improved stench fire-warning system for underground noncoal mines. Stench systems are the most widely used means of warning driers in underground noncoal mines of fires or other emergencies. A stench system alerts miners that an emergency condition exists by injecting an odorant into the mine air. Although stench warning systems have been used successfully for over 60 yr, present systems suffer several serious shortcomings, including odorant toxicity, unreliability of warnings, widely varying stench concentrations, and others. In 1980, the Bureau began a research program to upgrade the stench warning system. The resultant system overcomes the deficiencies of existing systems by substituting tetrahydrothiophene for the commonly used ethyl mercaptan stench odorant, and through the use of a specially designed stench injector. The improved injector reliably meters stench fluid into either ventilation-air or compressed-air streams at a precisely controlled rate. Prototype hardware has been fabricated and proof-of-concept tested under bath laboratory and in-mine conditions.

Jan 1, 1985