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By L. A. Stewart

"SUMMARYThis paper describes most of the chrysotile-asbestos deposits of Arizona. Mining methods are discussed briefly and asbestos-mill flowsheets are incorporated. Arizona asbestos mines are the only sources on the American continents of naturally iron-free chrysotile spinning fiber that is so urgently needed for electric-cable coverings, especially on warships.Asbestos was first recorded and recognized in Arizona in 1872, and a minor amount was produced from a deposit in the Grand Canyon in 1900. The discovery of a deposit in the Salt River district in 1912 initiated intensive prospecting, and deposits soon were developed. The total Arizona production of all grades of asbestos through 1953 is estimated at 30,000 to 35,000 tons.The deposits of the Central Arizona region, which are discussed in this paper, are scattered over nearly 2,000 square miles. The annual output is relatively small, because the asbestos occurs in thin, discontinuous veins and only in areas where intrusions of diabase are adjacent to or crosscut certain favorable units of the pre-Cambrian Mescal limestone. This stratigraphic limitation, combined with other essential geologic conditions, tends to restrict the size of the deposits.Virtually all of the deposits are in rugged, mountainous country, and many of the mines are on steep canyon walls. In the average mine, production of 1 ton of commercial asbestos requires removal of 30 to 40 tons of waste rock. Mining and transportation costs consequently are high.Several deposits of chrysotile that is somewhat harsh and of moderate tensile strength have been known for years but were not worked because of the former exacting demands of industry for high-strength, soft asbestos. However, improve¬ments in asbestos fiberization and spinning technique, combined with the urgent need for asbestos, have made this so-called semisoft fiber desirable, and deposits of this type now are being exploited."

Jan 1, 1955

By Richard L. Jenkins

Systematic sampling, in reconnaissance fashion, of the continental shelves of the United States to define favorable areas of offshore mineral deposits, is one of the long-range marine mineral; programs of the U.S. Department of the Interior. In mid-1966 the Department of the Interior launched its Heavy Metals Program to stimulate domestic output of gold which is in serious short supply. The program is jointly conducted by the Geological Survey and the Bureau of Mines.

Jan 1, 1968

By K. E. Stanfield

The Bureau of Mines oil-shale program, initiated in April 1944, is concerned with the future utilization of oil shale in the United States as a source of liquid fuel. One phase of this program is the accumulation of information on the location, extent, and richness of oil-shale deposits that may be suitable for processing to oil and related products. A previous publication5/ presented, by means of logs, the oil yields of sections of the largest known oil-shale deposit in this country -the shales of the Green River formation occurring in adjoining portions of the states of Colorado, Utah, and Wyoming. This present supplementary report presents the oil yields of cores from 48 holes drilled during 1952 to 1954 in the Green River formation of Colorado, which is distributed over an area of more than 1,000 square miles. The oil yields of the 48 oil-shale sections, involving the assay of 9,651 samples, representing 22,451 feet of core, are presented by means of logs. In addition, the oil yields of samples comprising the maximum sections of 15 gallon-per-ton shale are tabulated for these cores and for the 28 cores from Colorado which were logged in the previous report.

Jan 1, 1957

By D. H. Platt

Bauxite, the principal source of aluminum, has been mined from deposits in Saline and Pulaski Counties, Ark., since 1899; war needs have greatly stimulated production. Many of the ore deposits are basin-shaped and either outcrop or are covered by a shallow-depth overburden at their peripheries; these are mined by stripping and open-pit methods. When stripping becomes economically impracticable, incline shafts or slopes are sunk on the dips of the deposits, and underground mining is done on the retreat, using a room-and-pillar method.

Jan 1, 1945

By Ronald H. Church, Walter E. Pittman, J. T. McLendon

In its role of providing technical assistance to the mining industry, the Bureau of Mines' Tuscaloosa Research Center has conducted research to develop trapped miner location systems which would aid in locating miners trapped by underground mining disasters. Efforts to produce electromagnetic systems for the location of trapped miners underground and to communicate with them were surveyed, from the 1920's to 1981. Theoretical studies of through-the-earth electromagnetic transmissions are described as well as studies of the electrical characteristics of various rocks, minerals, and soil. Several trapped miner location systems are reviewed including the Westinghouse systems, the DEVELCO system, and an automated three-dimensional location system, and the phase difference of arrival technique. Tangential research, relevant to trapped miner location systems is described. A comprehensive bibliography covering all aspects of trapped miner, through-the-earth electromagnetic location and communications systems is appended.

By Mary S. Esfandiary

This list of organizations that conduct research and development programs on coal has been compiled by the Bureau of Mines with the thought that such a directory may provide a useful guide to worldwide research efforts in the areas designated and may facilitate communication between organizations with similar interests. This list includes government, university, private, and commercial organizations. Many of these groups are conducting comparatively modest but often particularly interesting or specialized investigations. The areas of investigation have been defined in a broad manner--these include analysis and constitution, mining and geology, preparation, combustion, briquetting, high- and low-temperature carbonization, gasification, hydrogenation, Fischer-Tropsch, and health and safety. In some instances such information is not available, but the names of the organizations themselves often indicate immediate arias of interest. Special publications issued by and describing the work of each organization have been cited, when known; almost all of the organizations also publish results of their investigations in the technical press. Several foreign technical and trade publications that include such information and are not published directly by any of the organizations listed are cited in the pages following the list of organizations in each country. This list is not complete. Information that would improve coverage and/or accuracy will be welcomed by the Bureau of Mines.

Jan 1, 1961

By Raymond B. Ladoo

"The increasing realization of the fire hazards involved in the use of wooden shingles caused the National Lumber Manufacturers' Association to beginsome five years ago a search for a suitable fire-resistant paint. The problem was submitted to the Educational Bureau of the Paint Manufacturers' Association of the United States and work was started by Mr. Henry L. Gardner at the Institute of Industrial Research, Washington D.C. in collaboration with Dr. Herman von Schrenk, a timber expert of St. Louis.The results of this,work have been described by Heckel, in ""Asbestos"", (Heckel G.B., Asbestos in the Paint Industry, Asbestos, Vol. 2, July, 1920,pp.- 5-10).,,who gives the following formula for one of the colors as typical: It will be noted from this formula that ""asbestine"" forms 33% of the total liquid pigment by weight or 31.8% of the solid constituents. Hockel in the article referred to describes this paint,as ""asbestiform"" and assumes since ""asbestine"" is magnesium silicate it must be the chrysetile variety of ""Asbestine"", however, is not asbestos but is a trade name for a fibrous variety of talc mined in the Gouverneur district, St. Lawrence County, New York. This rather natural error persists through the article and credits asbestos with many desirable properties which are characteristics of talc."

Aug 1, 1920

By H. E. Hilliard

The Bureau of Mines investigated hydrometallurgical procedures for concentrating precious metals from a mechanically processed metal fraction of obsolete military electronic scrap. Feed material for the leaching procedures described in this report was the high-tension-separated metal concentrate obtained as a fraction from mechanically processing partially stripped electronic units. Initial pretreatment with a 20-wt-pct-NaOH solution solubilized most of the aluminum. After washing, the resulting residue was incinerated to destroy any organics attached to metal particles. The incinerated residue was leached with 20-vol-pct H2S04 solution using two methods, countercurrent pressure and ultrasonic-aided leaching to solubilize the base metals, predominantly copper. Silver was recovered from the base metal leach residue using 50-vol-pct HN03, and gold contaminated with several percent palladium was recovered from the silver leach residue using aqua regia. The impure silver and gold plus palladium products represent about 1.5 wt pct of the high-tension-separated metal concentrate. Included is a three-step process evaluation study of mechanical processing of general electronic scrap and two hydrometallurgical procedures for leaching high-tension-separated metallic concentrates obtained from the mechanical processing step. Process evaluation concluded that only mechanical processing is economically viable.

Jan 1, 1985

By Ramie H. Thompson

1.1 BACKGROUND In many underground coal mining operations the use of electromagnetic field equipment, particularly communication systems, not only increases the overall efficiency of the mining operation but can be directly linked with mine safety considerations. The use of electromagnetic field producing equipment in underground coal mining operations can only be expected to grow. Several new communication systems have already been proposed. In addition, high-frequency producing equipments for many diverse uses in mining operations are under study. The use of these equipment in underground mining operations is hampered by the possibility of their electromagnetic fields interacting with the electric blasting cap operations commonly carried out in the mines. Such interactions can have at least two results bearing directly on mine safety: o premature initiation of the cap, either in its normal shot location or during hookup or transportation; o dudding of the cap so that normal firing operations do not cause irritation; thereby leaving unexploded high explosives after normal firing. Since the consequences of a premature initiation could, particularly in coal mines operations, result in catastrophe involving human life, the overall approach to prediction of possible hazard must be, as far as possible, of a "worst case" nature. The general problem of predicting possible RF hazards for any electroexplosive device (EED) is best treated by reference to Appendix A of

Jan 9, 1983

By S. H. Ash

Probably one of the most significant departures in tunneling practice is the introduction of Diesel locomotives far haulage (Diesel trucks have been used for some time). The fallacy of the belief that they do not generate carbon monoxide or toxic gases and can be used indiscriminately has been proved by the authors through observation for several years of atmospheric conditions surrounding the use of Diesel engines in tunnels. Diesel locomotives haves been introduced in tunnel haulage for reasons other than safety or health. Except to the extent that they replace trolleys, with their danger of causing electrocutions, modern Diesel locomotives do not increase safety Or remove any ordinary hazards to safety or health. In fact, they create such hazards, the extent of which is limited entirely by the carbon monoxide-content level set, method of ventilation, adequacy of the measures.

Jan 1, 1942

By M. M. Fine

This Bureau of Mines report describes the theory, experimental procedures, and the results obtained to date in the development of the Bureau's process for magnetically roasting iron ores using scrap iron as a means of reduction. Since magnetic separation is an operational step common to magnetic taconite plants, the preliminary research studies emphasized only the novel magnetic roasting step. The studies included the use of automobile scrap, ferrous reductants such as borings and turnings, and prereduced pellets. Technical feasibility of the process was demonstrated both on a bench- and pilot-scale. Quality magnetic concentrates with recoveries of over 90 percent were obtained from a direct shipping ore containing 59.5 percent Fe and from fine grained semitaconites with about 30 percent Fe.

Jan 1, 1966

By John C. Gagliardi

The size and complexity of modern surface haulage trucks has resulted in an increased reliance upon sensors and electronic-based instrumentation for safe and efficient operation. Design engineers need accurate information about the equipment vibration environment to efficiently and effectively build components for installation on mobile mining equipment capable of withstanding the mine environment. Examples of such components include backup alarms, communication equipment, microprocessor-based controllers, and a wide variety of sensors. Unfortunately, this information is not available to the majority of both original equipment and aftermarket equipment manufacturers. To address this problem, the U.S. Bureau of Mines performed field vibration measurements on a variety of surface mining haulage trucks. The vibration measurements were then analyzed and test specifications were developed in the form of envelopes. In conjunction with test specifications, recommendations to aid manufacturers in implementing a vibration environment test program have been included with an illustrative example.

Jan 1, 2010

By Robert E. Wood

[The temperature dependency of the low-density thermal conductivity coefficients, ?°T, of nitrogen, 100° to 1,200° K, is correlated with the Keyes' equation, ?T ½ -1 -12/T) WT = aT+ bT 10 The equation ?T,P = ?°T +a[ ]ß represented 509 experimental higher V pressure thermal conductivities in the temperature range 131.2° to 973.15° K for pressures to 500 atmospheres, with a mean absolute deviation of 2.35 percent. This equation was used to compute thermal conductivities of gaseous nitrogen for 47 pressures, 1 to 240 atmospheres, and 110 temperatures, 133° to 740° K, which are common to conditions encountered in Bureau of Mines helium purification processes. Isobaric heat capacities, CP, and viscosities, ?T,P, from previous work were combined with the present thermal conductivities, ?T,P, to compute Prandl1 numbers, C?T P / ?T ,P, of nitrogen. Tabular values of Prandtl num¬bers are presented for 49 pressures, 1 to 240 atmospheres, and 75 temperatures, 133° to 740° K. Estimated uncertainties are ±5 percent in the tabulated thermal conductivities and ±15 percent for the computed Prandtl numbers. However, the uncertainty may rise to ±10 percent for thermal conductivities and to ±30 percent for Prandtl numbers as the critical conditions of nitrogen are approached.]

Jan 1, 1971

By E. G. Davis

The flash reduction of fine iron ore in a dilute-phase system was investigated at 500° to 900° C within a heated stainless steel tubular coil. Alabama brown iron ore and Mesabi semitaconite ore were fed into the coil concurrently with reducing gases of hydrogen and reformed natural gas, so that the velocity of the gas at the reaction temperature was sufficient to entrain and pneumatically transport the solids through the coil. Reduction is very rapid with retention time of the ore in the coil varying from 4 to 15 seconds. Variables affecting reduction are temperature, ore feed rate, and gas flow or velocity. Results of the studies show that a partially reduced product (10-to 25-percent reduction) can be made which, on subsequent magnetic concentration, yields a concentrate containing 64 to 70 percent iron with a 90-to 94-percent iron recovery. Maximum reduction of 77 percent was obtained when hydrogen was used in a four-stage reduction test to yield a product containing 61 percent metallic iron.

Jan 1, 1972

By J. H. Weber

This Bureau of Mines publication describes the hardware system and software package for the semiautomatic acquisition and automatic processing of high-resolution mass spectrographic plates. The semiautomatic data acquisition allows a tenfold saving of time compared with manual data acquisition. Automatic processing of the high-resolution data to yield exact masses, intensity, and the corresponding empirical formulas is accomplished by efficient programming on a small, inexpensive, programmable calculator system.

Jan 1, 1974

By John F. Papp

The Bureau of Mines has sampled microstructure of low-pressure flat flames by mass spectrometer for normal methane-oxygen-argon and for methane-oxygen-argon-bromotrifluoromethane flames. The physical and chemical phenomena, and the method of analysis of mole fraction data to evaluate net reaction rates are here considered in detail. Included is a computer program listing with output on one flame. Chemical species considered are CH4 , CO, CO2, H, H20, OH, Ar, H2, O2 , O, H2CO, CH3 , CF3Br, HF, HBr, Br, CH3Br, HCO, F2CO, CH2 CF2 , H02.

Jan 1, 1975

By John W. Frey

This paper presents one of a series of digests of foreign mining legislation and court decisions that is being prepared in advance of a general report relative to the rights of American citizens to explore for minerals and to own and operate mines in various foreign countries . This interpretation of the mining law of Australia was first compiled from the best information available in Washington; it was then sent to the American Consulate General , in Australia, where through the direction of Thomas H. Robinson , American consul in charge , it was submitted for criticism to the mining authorities in the various States of Australia , whose suggestions have been incorporated in this digest .

Sep 1, 1930

By Alexander May

In its role to provide technology to prevent or limit adverse environmental impacts associated with mining or minerals processing, the Bureau of Mines has conducted research at its Tuscaloosa Research Center to asess the environmental impacts of phosphogypsum produced by the Florida phosphate industry. Over the years, stockpiles containing 335 million tons of phosphogypsun have accumulated and the industry continues to generate an additional 33 million tons a year. Samples from approximately 1,000 feet of drill core, obtained from nine stockpiles were characterized using chemical, X-ray diffraction, emission spectrographic, radiological, and physical means. The data developed indicated that phosphogypsum is not a corrosive or toxic hazardous waste as defined by Environmental Protection Agency criteria. Radium concentration averaged 21 picocuries per gram and its content was inversely related to particle sizes. Thirty-nine elements were detected in phosphogypsum; concentrations of these elements did not vary with depth within the stockpiles.

Jan 1, 1982

By D. K. Ingram, G. L. Mowrey, T. R. Rehak

Problem: Blasting is a hazardous component of surface mining. Serious injuries and fatalities result from improper judgement or practice during rock blasting. This paper describes several fatal injury case studies, analyzes causative factors, and emphasizes preventive measures. Method: This study examines publications by MSHA, USGS, and other authors. The primary source of information was MSHA’s injury-related publications. Results: During the 21-yearperiod from 1978 to 1998, the mean yearly explosive-related injuries (fatal and nonfatal) for surface coal mines was 8.86 (95% CI: 6.38 -11.33), and for surface metal/nonmetal mines 10.76(95% CI: 8.39 - 13.14). Flyrock and lack of blast area security accounted for 68.2% of these injuries. This paper reviews several case studies of fatal injuries. Case studies indicate that the causative factors for fatal injuries are primarily personal and task-related and to some extent environmental. A reduction in the annual injuries in surface coal mines was observed during the ten-year period of 1989 - 1998 [5.80 (95% CI: 2.71 - 8.89) compared to the previous ten-year period of 1979 - 1988 [10.90 (95% CI: 7.77 - 14.14)]. However, such reduction was not noticed in the metal/nonmetal sector, i.e., 9.30 (95% CI: 6.84 - 11.76) for the period 1989-1998compared with 11.00 (95% CI: 7.11 - 14.89) for the period 1979-1988. Discussion: A multifaceted injury prevention approach consisting of behavioral/educational, administrative/regulatory, and engineering interventions merits consideration. Impact on industry: The mining community, especially the blasters, will find useful information on causative factors and preventive measures to mitigate injuries due to flyrock and lack of blast area security in surface blasting. Discussion of case studies during safety meetings will help to mitigate fatal injuries and derive important payoffs in terms of lower risks and costs of injuries.

By William M. Nabors

As a part of a program to promote conservation and efficient utilization of petroleum resources, Bureau of Mines engineers are studying secondary oil-recovery projects in the United States. Published reports that set forth the pertinent facts of these operations help others to profit by the experience gained. This report presents the results of a study of secondary-recovery methods used in Kentucky by the Cumberland Petroleum Co. on its L. C. Bailey lease, Oil Springs pool, Magoffin County, Ky. This is believed to be the first water-flooding project in eastern Kentucky (fig. 1).

Jan 1, 1958