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By Frank D. Lamb

Pyrophyllite, a hydrous aluminum silicate (Al2 Si4O10 (OH)2 ) has been mined in North Carolina and marketed without beneficiation for the past 100 years, but recent demands for higher-grade material indicate that an economical concentration method is needed for at least a part of the pyrophyllite production. Past production has depended upon selective mining and hand sorting, which is often unsatisfactory because of the finely disseminated character of the ores. The major impurity in North Carolina pyrophyllite ores is quartz, which accounts for the abrasiveness of the commercial product. Since pyrophyllite is only slightly heavier than quartz, those ores cannot be beneficiated by simple gravity-concentration methods. Some separation can be attained by differential grinding and air classification because of the difference in hardness of the two minerals) but the separation is not sharp. Froth flotation of pyrophyllite from Quartz has never been attempted commercially, but if the demand for high-grade material is sufficient, it would seem that this process offers the most premise of being economically feasible.

Jan 1, 1950

By E. G. Davis

Under a memorandum of agreement with Reynolds Metals Co., Richmond, VA, the Bureau of Mines studied the problem of corundum formation on refractory linings in aluminum recycling furnaces. A laboratory test was developed for evaluating refractories in contact with molten recycled aluminum and identifying the mechanism of corundum formation. A test apparatus was designed and constructed to evaluate the performance of refractory samples. Corundum mechanism formation studies indicated that corundum formed on refractories when there is metal penetration. Once corundum forms, it acts as a wick allowing the molten aluminum to move to the surface where it is oxidized, thus causing further growth of the corundum. Phosphoric acid treatment or a spinel mortar coating prevented corundum formation on the 70-and 90-pct-A1203 refractories.

Jan 1, 1988

By G. L. Neumann

The Guymard mine in Orange County, N. Y., is reported to have been discovered in 1862 and mined until 1876, producing 10,000 tons of lead and zinc ore. The property was examined by an engineer of the Bureau of Mines in 1948. Development work was done by the Bureau in April and May 1949 and March 1950. During these two periods four drill holes totaling 2,090 feet were completed. The mineralized sections of the core were sampled and assayed.

Jan 1, 1952

By G. L. Neumann

"INTRODUCTION AND SUMMARYThe Guymard mine in Orange County, N. Y., is reported to have been discovered in 1862 and mined until 1876, producing 10,000 tons of lead and zinc ore. 2/The property was examined by an engineer of the Bureau of Mines 3/ in 1948. Development work was done by the Bureau in April and May 1949 and March 1950. During these two periods four drill holes totaling 2,090 feet were completed. The mineralized sections of the core were sampled and assayed.ACKNOWLEDGMENTSThe diamond drilling was conducted under the general supervision of McHenry Mosier, chief, Mining Development Branch, Minerals Technology Division, Region VIII, and the direct supervision of Kenneth M. Earl and the writer as project engineers. Drill cores were logged by Paul K. Sims of the Federal Geological Survey. Chemical analyses were made by the Bruce Williams laboratories, Joplin, Mo., and the Minerals Processing Branch, Minerals Technology Division, Region VIII, Bureau of Mines, under the general supervision of Paul M. Ambrose, chief, and the direct supervision of Howard F. Carl, chief, Physical and Chemical Section.LOCATION AND ACCESSIBILITYThe Guymard deposit (see fig. 1) is on the west slope of Mount Hope, Orange County, N. Y., 1,500 feet northeast of Lake Guymard.Graham station, near the deposit, is on the Erie Railroad about 8 miles north of Port Jervis and 4 miles south of Otisville."

Aug 1, 1952

By G. A. Smyres

The Bureau of Mines conducted laboratory studies to determine the feasibility of chlorine-oxygen leaching for treating low-grade zinc sul-fide flotation concentrates. Recovery of zinc sulfides by flotation from complex fine-grained sulfide ores is substantially higher in low-grade bulk sulfide concentrates than in the high-grade cleaned concen-trates required for smelter feed. However, there is no commercial process in the United States for the treatment of low-grade bulk zinc sul-fide concentrates. Leaching experiments using reactors of 500-mL and I-gal capacity were conducted on a bulk concentrate containing 19.3 pct Zn, 35.6 pct Fe, and 39.4 pct S. The effects of pressure, temperature, and percent solids on extraction were investigated. The chlorine-oxygen leaching procedure showed promise for treating the concentrates. Zinc extractions of 95 pct or more were obtained by leaching at 50 pct solids in the temperature range of 1000 to 1200 C. Zinc extractions by leaching with chlorine followed by oxygen at reactor pressures of 50 to 100 psig were independent of pressure.

Jan 1, 1985

By E. L. Burwell

Preliminary results of an in situ oil shale retorting experiment conducted by the Bureau of Mines in a shallow bed of Green River oil shale at Rock Springs, Sweetwater County, Wyo., are described. Eleven wells were drilled into a 20-ft-thick section of the shale lying between 68 and 88 It deep, and attempts were made to connect the wells through the shale with a fracture system created by application of high-voltage electricity (electro-linking), hydraulic fracturing, and explosive fracturing. Ignition of the shale through the central well was easily achieved with a propane burner, and shale oil began to collect in three wells within 3 hours. Propane injection was discontinued after 7 days, and combustion continues, although attempts to control the direction of the combustion front have been unsuccessful. Production rates as high as 4 ½ barrels of nil per day have been recorded, but too little is known about underground conditions to permit an estimate of recovery efficiency at this time.

Jan 1, 1969

By D. Harrington, R. R. Sayers

For several years the writers have been studying various phases of the effect of air conditions in metal mines upon underground workers ; in 1918 a short study was made in certain hot and deep mines and brief reports were issued in the Engineering and Mining Journal ( August , 1920) and in the U. S. Public Health Reports (Vol . 36 , No. 4 , January 28 , 1921 ) . In 1921 a more extended study was made (also in hot and deep metel mines ) with intent to determine the limiting conditions imposed upon underground workers by the physiological effect of various air movements , temperatures , and humidities , with and without work . It is the purpose to publish a series of short papers on this later investigation , each paper to consider one particular phase of the work . The present paper deals with the effect on body temperature and pulse rate in still air as compared with moving air of temperatures from 90 to 100° F . and 100 per cent relative humidity, the subjects at rest .

Apr 1, 1923

By G. H. Martindill

Complex chemical and physical changes occurring during carbonization result in a heterogeneous system composed of gaseous, liquid, and solid phases, whose relative proportions and chemical compositions change constantly as temperature increases. Studies in which the participating variables are isolated and controlled should be useful in formulating the mechanism of coal carbonization. The most characteristic property of a coking coal is its ability to form a plastic mass at a certain stage of the carbonization process. During this period it is believed that fluidity of the coal influences the properties of the resultant coke. This report gives results of an investigation by the Federal Bureau of Mines of the influence of the maximum fluidity attained by the charge on the physical quality of the coke or char produced. As a first approach to the problem, researchers investigated high-melting-point pitches, which are relatively simple carbonaceous materials. The plastic properties of these pitches, prepared specially for this work, varied greatly; their fluidities, as measured by the Gieseler plastometer, covered most of the fluidity range characteristic of coking coals. Blending these pitches with increasing pro-portions of fine coke progressively reduced their fluidities. Coal-pitch and coal-coke blends also were treated; their fluidities were varied by changing their blending ratios. The various blends were carbonized in a small-scale carbonizer and the resistance of the carbonized residue (char) to abrasion was determined in a small-scale tumbler test, using the Roga drum.

Jan 1, 1960

By Andrew Allan

[This report describe the first experiment of the Anthracite Research Laboratory, Bureau of Miners, in attempting to reduce underground-mining costs and conserve anthracite as a natural r-source by introducing now minim methods. The work war, dons in cooperation with one of the large anthracite-producing companies. It applies to productive mining, characterized by comparatively low cost, per ton and high production per man, as differentiated from development mining, which is always necessary before the, productive or retreat phase can begin. The system d scribed in this report is believed to be generally applicable to beds pitching 70° to 90° and, under certain conditions, to beds pitching loss than 70°. After development hate been completed, an openings is made, extending the full width of the 9- to 10-foot coal bad and reaching from the haulageway to the vertical limits of the solid coal. Long drill holes (20 to 50 feet) charged with about one stick of permissible explosive riper foot of length are fused to break the coal. Once broken, the coal is loaded onto a shaker conveyor by gravity and thence into mine: cars. The coal is mined retreating in 15- to 20-foot sections that are broken and loaded onto the conveyor through a specially constructed chute. In the Bureau?s experimental work, the height of sections arse ranged from 35 to 60 fact, depending on the geologic extent of the coal bed.]

Jan 1, 1952

This manual is for use by mine operating personnel and vehicle manufacturers in the selection and proper use of automatic fire protection systems for underground metal and non-metal mining vehicles. Most of the currently available systems are manually operated, dry chemical fire suppression systems. When properly designed, installed, and maintained these systems have proven to be effective both in fire suppression and in withstanding the rugged mine environment. Portable fire extinguishers and manually actuated systems have provided adequate protection for most of the reported fire incidents. However, there have also been incidents where injuries and property losses would not have occurred if the vehicle had been protected with an automatic fire protection system. The need for reliable automatic systems exists when the operator is not present, especially when the vehicle engine is running without the operator in the cab; and also in cases where the operator leaves the vehicle to fight a small fire with a portable and is then forced to abandon the vehicle because the small fire becomes uncontrollable. In the later cases manual systems on the vehicle are never actuated. Although these incidents have been relatively few in number in the past, the increasing use of mobile diesel powered equipment and the related importance of personnel safety, high costs of the mining vehicles, and high cost of down time warrant consideration of automatic fire protection systems. The fire history data and the design concept discussed in this manual were developed under the Bureau of Mines Contract H0252038 which is part of the government's mining research safety program. The purpose of the contract was to develop a low cost, reliable, prototype automatic fire control system for underground vehicles. The industry needs were determined through an extensive mine visitation program, and the prototype system was demonstrated on a vehicle in an underground mine fire test. The system developed under this contract was specifically designed for a load-haul-dump. However, the design concept is applicable to the full general class of mobile underground mining equipment.

Jan 1, 2011

By C. A. Geffen-Fowler

This report, sponsored by the Bureau of Mines, presents the results of an examination of the safety of the Blind Shaft Borer (BSB) shaft sinking system and an alternative modified BSB design concept in comparison to conventional shaft sinking technology. Detailed study of the two systems was also performed to identify and recommend design changes for optimum safety conditions. A comparison of the BSB systems with conventional shaft sinking was made on the basis of relative risk levels. Risk incorporates both the frequency and the potential consequence of accidents. A safety evaluation of the component operations of the two BSB systems was performed using a Failure Modes and Effects Analysis (FMEA) methodology. The results of this analysis show generally that both BSB systems are safer than conventional shaft sinking. The potential risk of conventional shaft sinking operations could be reduced by over 30%, on the average, with the use of the original BSB system, and by an average of about 10% with the modified BSB. Design change recommendations to further improve the safety of these systems include better fire suppression systems, improved man haulage systems and more compact hydraulics. An operational safety manual was also developed for the modified BSB system.

Jan 1, 1981

By L. A. Readdy

Pilot Hole "X" was drilled to test the formations through which the ventilation shaft for the proposed U.S.B.M. demonstration oil shale mine will be drilled. The history of the drilling of Pilot Hole "XI' is presented. This historical summary provides the details of method used during the drilling of this hole. Problems encountered during drilling are discussed. The quantities of drilling mud and other materials used to drill the hole are documented.

Jan 1, 1977

By Glenn C. Reed

"Preliminary examination of the Glass Buttes mercury deposits, Lake County, Oregon, was made in August 1945 at the request of W. S. Lazier, present lessee of the deposit.Most of the prospect openings in the area were inspected. The more significant workings were sampled and napped in detail. This report presents the data obtained from the investigation to date.In its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. noon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests. Both these branches are under the supervision of Dr. P. S. Dean, assistant director.Special acknowledgment is due to S. H. Lorain, chief, Albany Division, Mining Branch and to S. R. Zimmerley, chief, Salt Lake City, Utah, Metallurgical Division, for analyses of the ores.The presence of quicksilver in the Glass Buttes district has been known since about 1930. The area immediately north of Middle Butte has been superficially prospected by numerous test pits, trenches, shafts, and short adits, which revealed a number of opalized zones. Many of these opalized zones contain weak to strong concentrations of cinnabar. The area has not boon explored thoroughly; no mercury has been produced from any of its deposits.A block of 48 full-size claims has been located to cover a large part of the area in sections 34 and 3, Tps. 23 and 24 S.,R. 23 E.,W.M. These claims, held by, location are owned by H. S. Miller, lumberman of Bend, Ore. W. S. Lazier, 10N. W. 20th Avenue, Portland, Ore., currently controls the property under,a nominal leasing agreement. J. W. McDaniel, 44 Lake Place, Bend, Ore., has done much of the underground and surface exploration on the property.The Glass Buttes district is an area of low relief in the Deschutes River drainage system near the northeast corner of Lake County, Ore. (See fig. 1.) The arid climate is marked by extremes of winter and summer temperature. Water for cane use is not available in the immediate area. Well water, however, can be obtained in limited supply on ranch property 5 miles to the south."

Aug 1, 1946

By C. E. Jordan

The fundamental properties of dielectric separation were studied to provide insight into the design and operating characteristics of a dielectric separator. Force equations on mineral particles were derived and evaluated experimentally. Responses to variations in the electrical voltage and frequency, feed rate, particle size, dielectric fluid, and dielectric constant were tested theoretically and experimentally, using a 5-cm-diam dielectric separator. High-dielectric mineral recovery was proportional to the calculated effective dielectric force volume (EDFV) that surrounded each drum-electrode wire. Electrode spacing was the most sensitive design parameter; spacing of less than 0.4 cm was required for a good separation. Dielectric separation was effective for separating minerals with dielectric constants that differed by approximately 2 or more.

Jan 1, 1985

By Raymond M. Stateham

Climatic conditions are compared with roof fall occurrence from April 1, 1972, to December 31, 1975, by the Bureau of Mines. These comparisons indicate that humidity has a strong influence on roof fall occurrence rates. Cubic regression techniques are used to develop best fit curves. Statistical analysis of these curves indicate that both are sinusoidal and exhibit positive correlation with each other. The sine waves have a period of 1 year with maximum and minimum inflection points in August and February.

Jan 1, 1978

By Lulie H. Crump

Salient historical data on consumption of fuels and energy have been summarized by State and census district for the years 1960 through 1972. This Information Circular covers States east of the Mississippi, and Information Circular 8705 covers States west of the Mississippi. These data replace previously published compilations of energy consumption statistics by States and districts. Future annual studies are planned using the same Btu conversion factors applied in these two. Information Circulars.

Jan 1, 1976

By C. J. Wilhelm, John M. Devine, Ludwig Schmidt

"Steel tanks often corrode rapidly in oil fields where the Gas produced with crude contains an appreciable quantity of hydrogen sulphide. In many instances working tanks have been discarded after only six months of service because of failure induced by corrosion.Aluminum has been used for some time in the fabrication of certain equipment incidental to the handling of oils containing hydrogen sulphide gas in solution, and has exhibited no carious corrosive action. These uses indicated that aluminum tanks,be equally effective in counter- acting hydrogen sulphide corrosion. Consequently, in the spring of 1920, an all-aluminum stock tank of 500 barrels capacity and a ""composite"" tank of equal capacity, having a steel bottom and bottom ring and an aluminum top and top ring, were placed in service on the State-Lassiter lease of the Gulf Production Co, in Crane County, Tex. These tanks were under observation for one year, the toot being sponsored by the Gulf Production Co., the Aluminum Co. of America, and the Parkersburg Rig and Reel Co. The results of this preliminary test sustained the belief that aluminum is highly resistance to hydrogen sulphide gas and likewise indicated the type or grade of aluminum which could be most economically used for lease tankage. However, in this preliminary test the tanks were not subjected to contact with the quantities o highly concentrated brines such as often are associated and produced with crude oil. Therefore, it was suggested by representatives of the aluminum Co. that additional tests be made to include production conditions in large quantities of brine would be handled, for pact experience had shown that aluminum often is susceptible to the corrosive action of brines."

Apr 1, 1931

By Mary S. Esfandiary

U.S. scientists attempting to maintain continuous surveillance of scientific information are confronted with two acute problems: The steady, even spectacular; increase in the volume of such information and the fact that much of it is published in unfamiliar foreign languages, According to the National Science Foundation, almost one-third of the world's scientific literature is published in languages that are read by less than 5 percent of U.S. scientists. Most scientists in the United States must rely on abstract journals and translations to obtain information on developments in research and investigations conducted in the non-English-speaking countries. However, there are problems involved in procuring suitable abstracts and translations and in obtaining such information as cheaply and rapidly as possible.

Jan 1, 1961

By R. L. Rock

The Bureau of Mines conducted radiation-ventilation studies in six large underground uranium mines to investigate the extent of radon-daughter exposure experienced by the miners and to analyze the ventilation systems to set what changes were required to achieve recommended radiation standards. The studies entailed tracing and measuring the mines' ventilating air, quantitatively and qualitaitively, from its entrance into the mines, through production areas, and lack to the surface. Pressures consumed in creating airflow through mine circuits were determined by altimeter surveys. Air quantities were measured with anemometers or by chemical smoke cloud methods. Air quantities delivered through tubing were determined using U-tube water gages to magnahelic gages to measure velocity pressures. Radon-daughters were filtered from mine air to measure alpha activity; activity levels were converted to "working levels," the established unit for reporting miner exposure. Attention was given to locating unnecessary contamination influx sources and recirculating air. The radiation-ventilation surveys showed that where basic principles of food ventilation were not followed, high alpha radiation levels invariably resulted. Some mines required more primary air for controlling radiation levels throughout active areas, but more efficient use of available air was generally possible. Premature contamination of intake air was prevalent where development Openings intersected ore or passed by worked-out stopes. Several auxiliary systems were inefficient in secondary distribution, recirculating air already too highly contaminated for ventilation. Many got these common problems can be traced try the lack of dine planning with radiation control in mind.

Jan 1, 1969

By R. S. Dean

The possibility of cheap electric power for a number of mining areas in this country has suggested to many the idea of electric smelting of nonferrous ores in small units at or near the mines. The electric smelting of nonferrous ores was tested fairly thoroughly 20 years ago by United States Bureau of Mines and by others, and the fact that it did not achieve continuing workable success in any instance is sufficient proof that it offered no advantages at that time.

Jan 1, 1937