Search Documents

By L. H. Banning

The Bureau of Mines conducted pioneering batch and laboratory cyclic tests that simulated plant operation in developing a procedure for acidulating phosphate rock with fluosilicic acid. Both high-grade deslimed phosphate rock and low-grade phosphate rock samples were treated. The most promising results were obtained by acidulating des limed high-grade material. In a series of seven cyclic tests, 85.4 percent of the P20S was recovered in solutions. The average P2O5 content of the phosphoric acid-monocalcium phosphate solutions of the first step was 156 grams per liter, and the average fluorine content was 4.7 grams per liter. Residues had an average fluorine content of 30.7 percent and contained 83.9 percent of the total fluorine in the charge materials. Some fluorine was lost by volatilization.

Jan 1, 1975

By Damon C. Gray

This report contains a recommended program of acoustic research to be conducted by the U. S. Bureau of Mines. The program is directed toward the abatement and control of machinery noise in underground coal mining operations. The study conclusions and specific problem areas which led to the definition of the recommended program are also briefly described.

Jan 1, 1971

By Oliver Bowles

Sandstone, a widely distributed siliceous sedimentary rock, is the third most popular building stone in the United States. It is formed by the breaking down of preexisting rocks by weathering, subsequent segregation of the detrital quartz grains into discrete deposits by the sorting action of water or wind, and finally cementation of the quartz sand into a coherent rock. The homogeneity and resistance to weathering of the resultant sandstone make it suitable for exterior construction. Its excellent wearing properties explain its popularity for flagging and stair treads. However, quarrying and dressing methods and costs are adversely affected by the abrasiveness and hardness of sandstone especially as compared to limestone.

Jan 1, 1963

By Louis Schaffer

The purposes of the research were to assess the applicability of new accident investigation methods to mining accidents, and to adapt those found to be applicable in the development of a new methodology for use in mining. The development included field testing, evaluation and modification of the new methodology. The report is in two volumes. Volume one discusses the background research, the design of a methodology for field evaluation, preliminary field tests in Utah mines, and work done to prepare for a formal, complete evaluation by federal government mine safety officials. This, volume 2, discusses the field evaluation done by the contractor and cooperating mines after the program was re-directed by the Bureau of Mines. It relates to research done during a period of approximately eighteen months, ending in April, 1983.

Jan 1, 1986

By Donald C. Strimbeck

The Bureau of Mines designed a down-fired refractory-lined combustor that efficiently burned pulverized coal to produce a gas suitable as working fluid for an open-cycle gas turbine. The gas contained relatively little carbon, so the load on the ash-separation equipment was significantly reduced. Moreover, reduction in carbon content of the gas increased the average density of the solid particles making them more amenable to removal by centrifugation. Centrifugal-type separators failed to remove sufficient ash; however, to limit blade wear enough to achieve operating periods generally deemed necessary for commercial practicability.

Jan 1, 1969

By Alla D. Mah

The heat of formation of scandium sesquioxide (Sc203) has not been measured previously, and existing values for gallium sesquioxide (Ga203) are subject to large uncertainties. As a consequence, thermodynamic calculations involving these oxides hare lacked scientific exactness. This paper reports newly determined values of the heats of formation of gallium and scandium sesquioxides at 298.15° K., by combustion calorimetry. The corresponding free energies of formation are derived from heat and entropy data.

Jan 1, 1962

By Foster Fraas

The most important lithium resource in the United States is in the form of the feldspathoid mineral spodumene. This mineral has not been used to any important extent as a source of lithium salts or lithium metal, as other more easily decomposed minerals have b en available in sufficient quantity to supply the relatively small demand. The need for cheaper lithium salts for such promising new uses as air conditioning or dehumidification and of lithium feldspar for use in the glass and [ramic] trades has justified the recent work done by the Bureau of Mines on King available, through improved beneficiation and extractive processes, some of the lower grade but extensive spodumene deposits.

Jan 1, 1937

By Foster Fraas

The most important lithium resource in the United States is in the form of the feldspathoid mineral spodumene. This mineral has not been used to any important extent as a source of lithium salts or lithium metal, as other more easily decomposed minerals have been available in sufficient quantity to supply the relatively small demand. The need for cheaper lithium salts for such promising new uses as air conditioning or dehumidification and of lithium feldspar for use in the glass and [ramic] trades has justified the recent work done by the Bureau of Mines on [king] available, through improved beneficiation and extractive processes, some of the lower grade but extensive spodumene deposits.

Jan 1, 1937

By Harvey L. Pastan

The purpose of the investigation and analysis described in this report is to assess the data flow requirements that are required for remote supervisory control of a continuous mining system. Since these control concepts as applied to continuous underground mining are still in a formative stage at the present time during the first half of 1975, assumptions had to be made based upon engineering judgment as to what embodiment of mining machinery and control methodology seemed most feasible for achieving such a system. Based upon these assumptions and estimates of the control system's accuracy and response requirements, it was then possible to estimate the communication requirements for the assumed system configuration. 2. Approach The team members responsible for this study visited numerous coal mines to observe room and pillar mining operations in both high and low coal. The objective was to observe the methods of operating a variety of continuous mining machinery and haulage equipment with a view toward defining the problems to be overcome in the application of automation to the coal extraction process. Descriptive information concerning the mining equipment was obtained through contacts with the manufacturers. Conferences with Bureau of Mines personnel, equipment manufacturers and developers, and mine operators were held to explore the current thinking and developments being pursued toward automation and increasing both production and productivity.

Jan 1, 1975

By Arnold O. Tanner

Tables based on 1985 data, which were not available in time for publication of the "1985 Minerals Yearbook," are included in this chapter; corresponding tables for 1986 are not yet available. Raw nonfuel minerals produced in the United States during 1986 had an estimated value of $23.5 billion, an increase of $0.25 billion over the 1985 value. This is the fourth consecutive year that the value has increased, and except for a de- crease in 1982, the value each year has increased since 1971, or 14 out of 15 years. Industrial minerals growth slowed from a 3% increase in value in 1985 to a 1.5% increase in 1986, reflecting the slow growth in the domestic economy. The value of industrial minerals, more than three times larger than the value of metals, easily offset the less than 0.5% decline in the value of metal mine production. Although the decline was small, this decrease makes 1986 the fourth year in the past 6 years in which a drop in the value of metal mining production occurred in the United States. U.S. production continued to lag behind the growing world production. Overall, the estimated raw nonfuel mineral production rose 1% over that of 1985. Domestic mine production of ferrous metals declined as follows, in decreasing order of production: nickel, iron ore, tungsten, and molybdenum. All remaining domestic primary nickel and tungsten mines had closed down by yearend. Nonferrous metals that similarly declined included titanium, rare-earth metals, lead, silver, zinc, and magnesium. For the second consecutive year, aluminum, produced predominantly from imported bauxite, declined in production, while imports reached record-high levels. Somewhat modest gains were made in beryllium and copper. As has been the case for a number of years, gold was a bright spot in the domestic and internation-al metal mining industry. Gold production was spurred on by the increasing usage and development of heapleaching techniques that make lower grade ores, which were previously uneconomical, profitable. Additionally, various mining companies, the U.S. Mint, individual States, and a number of foreign countries began production of gold bullion and commemorative coins. Gold output in the United States increased from 2.43 million troy ounces (revised) in 1985 to about 3.73 million troy ounces in 1986, a dramatic 54% rise.

Jan 1, 1988

By Doris M. Hyde

The 350,000-barrel-per-day Bahamas Oil Refining Co remained closed throughout 1986. Financially troubled Charter Oil Co., joint owner of the refinery with Chevron Oil Bahamas Ltd., agreed in principle to have Chevron assume full ownership in return for canceling debts owed Chevron. Finalization of the agreement was pending at yearend. Burmah Oil Ltd. took more than a $30 million loss on the sale of its interest in South Riding Point Grand Bahama Transshipment Terminal to South Riding Point Terminal Holding Ltd.

Jan 1, 1988

By Edward L. McHugh, Charles Sabine, David G. Long

While less than 1% of reported mine accidents are associated with slope stability problems, slope failure accidents were responsible for about 15% of U.S. surface mine fatalities between 1995 and 2003. Small rockfalls, which may involve hand-sized rocks weighing only a few pounds, can cause fatal injuries to workers away from the protection of large machinery. Massive highwall failures containing a million cubic yards of material or more can be fatal even for heavy-equipment operators. As part of an ongoing study at the Spokane Research Laboratory, several remote sensing technologies are being evaluated as tools to assess slope stability and monitor slopes for hazards. An interferometric radar device capable of detecting very small displacements on slopes has been assembled and tested. Radar techniques can provide new tools to augment current methods for monitoring ground control hazards in mines.

Severe whipping of shuttle car trailing cables occurs when the car stops suddenly or reverses direction. This causes cable damage, and can seriously injure personnel near the cable. FMC has contracted with the U.S. Bureau of Mines to design, build and demonstrate a reel control system that will significantly reduce or eliminate whipping. II. CONCLUSIONS Results of engineering effort show that the following conditions are primarily responsible for the whipping problem. Causes may exist individually, or in combination.

Jan 1, 1972

By G. M. Martinez

The Bureau of Mines has investigated methods for the recovery of byproduct heavy minerals from sand and gravel operations in Oregon and Washington. These heavy minerals are not currently recovered except for gold in a few areas. The recovery of byproduct heavy minerals would provide a domestic source of minerals presently imported, and a more efficient use of domestic resources would be accomplished. Samples from more than 40 locations were treated by gravity separation to yield heavy mineral concentrates (black sands). Magnetite, ilmenite, zircon, rutile, chromite, platinum-group minerals, radioactive minerals and gold were identified in the concentrates. Individual zircon, ilmenite, chromite; magnetite, and gold products were recovered from selected concentrates by low-and high-intensity magnetic, high-tension, and heavy-medium separation techniques. The recovery for the individual mineral products ranged from 67 to 95 pct.

Jan 1, 1981

By Oliver Bowles

"INTRODUCTION Slate has earned a high reputation as a roofing material, carefully selected and properly placed it is rainproof, attractive, and extraordinarily durable. Despite there qualities in its favor, the slate industry during the past 30 years has suffered marked reduction in volume of sales. An increase in building construction and general improvement in business will doubtless bring renewed activity, but considerable ground has to be recovered before the industry can become prosperous. Influences tending to dwarf this long-established industry producing materials of world-wide reputation are analyzed briefly in the following pages in the hope that they may be rectified.HISTORY OF SLATE PRODUCTIONFigure 1 shows graphically the rise and fall from year to year of sales of roofing slate since 1885. In quantity, the peak was reached in 1902, and the most serious decline was from 1912 to 1918, sales at the end of this 6-year period being only one third those at the beginning. Unlike most building materials, slate experienced only a slight recovery in volume of sales during the post-war period, 1920-29. The value closely parallels the volume up to the World War period. Subsequently, however, as unit values increased the aggregate value rose sharololy above the volume curve, attaining in 1928 the point reached in 1903, although the Lumber of squares sold was scarcely one third as great. The increased unit value was due partly to larger sales of heavy architectural grades."

Nov 1, 1933

By J. G. Donaldson

Nickel containing less than 0.01 percent of total metallic impurities was produced at the Rolla Metallurgy Research Center of the Bureau of Mines by electrodeposition from purified electrolytes. The first report on this research4 described purification of electrolytes by selective precipitation and by liquid-liquid extraction. This second report describes a procedure: or electrodepositing high-purity nickel from electrolytes purified by passing a nickel ammine solution through a column of an ion exchange resin. The nickel electroplated directly from the ammine solution without further treatment; a titanium cathode and two platinum anodes were used. The nickel deposit was dense, smooth, and adherent, and contained less than 0.001 percent each of cobalt, copper, and iron, and spectrographically detectable traces of aluminum, magnesium, and silicon. Nonmetallic impurities in the nickel metal were carbon and sulfur, each present in concentrations of less than 0.01 percent. The results of several experiments planned to purify solid nickel salts by zone refining are also reported. These salts, after purification, were intended for use in preparing electrolytes for deposition of high-purity nickel. Results were not encouraging so that the more promising ion exchange procedure was emphasized chiefly.

Jan 1, 1962

By S. J. Aresco

The Bureau of Mines has been active in promoting the purchase of coal for Government use under specifications that define the requirements in terms of heating value of the coal, expressed in British thermal units, and the composition as shown by proximate analyses. To these, when required, are added the ash-softening temperature, the free-swelling index, and the Hardgrove grindability index. Under most of these specification contracts the bidders guarantee the quality of the coal, and that guaranteed by the successful bidder becomes the standard of his contract. The deliveries are sampled in accordance with instructions 5/ issued by the Bureau of Mines; the samples are analyzed in the Bureau laboratory to determine whether the coal is of the quality guaranteed by the contractor and, if it is not, a price adjustment is made. Analyses of the delivered coal and tipple samples (samples collected at mine tipples as coal is being loaded into railroad cars or trucks) provide valuable data for use in evaluating future bids. In addition, the continuous sampling of coal as delivered is a check on the practical results obtained in burning the coal.

Jan 1, 1962

By Martin D. Conyac

A 1984 Bureau of Mines investigation identified ho mineral resources in the Wilderness Study Area (WSA). However, four prospects in the WSA contain anomalous amounts of copper and silver minerals; one had traces of gold. Stratabound copper-silver occurrences appear to be prevalent. Quartz veins in the WSA locally contain trace gold, and one mine adjacent to the area produced some gold in the late 1800's. The WSA is underlain principally by Precambrian and early to middle Paleozoic quartzites, argillites, dolomites and limestones that have been complicated by faulting, generally tilted northeastward, and thrust southeastward over sequences of late Paleozoic sedimentary rocks. The stratabound copper-silver occurrences and gold-quartz veins are in Precambrian and Cambrian rocks in the western part of the WSA, as are similar deposits regionally. Sand and gravel, and limestone are abundant, but plentiful resources of these commodities are nearer established markets. In November 1983 there were 5 small groups of current claims oh the WSA boundary; none are patented claims. Probably less than 35 claims have been located within the WSA, mostly in the northwestern portion; hut over 100 claims have been located outside, near the northwestern boundary. Oil and gas leases nearly surround the boundary and 6 extend up to 1 mile into the study area. There has been no recorded mineral production from within the WSA. From 3 to 5 miles to the west, several lode nines in the Johnnie district have produced several million dollars worth of gold from quartz veins, and some silver and lead from galena-calcite veins. These veins generally trend northeasterly and dip northwesterly and probably do hot extend into the study area.

Jan 1, 1985

By I. Liebman

Two triggered barrier systems and several extinguishing agents were tested against coal dust explosion propagating in the main entry of the Bureau of Mines Experimental Mine at Bruceton, Pa. One system used a high-pressure cylinder to propel the extinguishant; the second system used pressurized nitro-gas or Halon 1301 (CF3Br) in a low-pressure system to power the disperser. The relative efficiencies of the extinguishants were determined by compar¬ing calculated concentrations of the extinguishant clouds present in the mine during suppressing of the explosions. Results showed the following trend of increasing effectiveness: Purple-K (KHC03)<water<hybrids consisting of foam or water combined with Halon 1301<Halon alone. On a weight basis, water was two to three times as efficient as Purple-K, whereas the hybrids and Halon alone were only marginally superior to water. Maximum efficiency of an extinguishant is attained by high rates of discharge from the barrier and by minimizing the time interval between onset of discharge and flame arrival to that necessary for discharge. Both the high- and low-pressure barrier systems were demonstrated to be capable of suppressing coal dust explosions; however, because of the potential hazard of the former, the low-pressure system is considered to be the most attractive prototype.

Jan 1, 1979

By Leonard Obert

The ultimate object of this investigation is to develop a method for determining the pressure, in- situ, on rock mine pillars, arches, end other mire structures. The preliminary investigations of Bureau of Mines engineers, as well as those of other investigations4/ have shown that, the velocity of sound depends on the pressure if it is dependent to such an extent that a measurement of the velocity might be used as a means of determining the pressure, a sonic method of measuring the pressure on rock mine columns is possible. Briefly the method would require, first, laboratory determination of the variation of the velocity of sound with pressure in samples of rocks taken from mine pillars to establish a. velocity-pressure relationship for the type of rock and, next, measurements of the velocity of sound in the mine pillars from which the laboratory samples were taken. The pressure on the pillars could be determined by correlating the velocity in the pillar with the velocity-pressure relationship established in the laboratory. Obviously the success of the method depends on the extent to which the velocity of sound varies with pressure in rock.

Jan 1, 1939