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By Ted C. Briggs

The Bureau of Mines is evaluating the thermodynamic properties of helium and helium-containing mixtures. Twenty-two compressibility runs were made with helium at 0° C and pressures to 800 atmospheres using a Burnett-type apparatus. Data from the 22 runs were treated simultaneously and as separate runs while different functional forms and weighting factors were used. A fourth-degree-polynomial equation in the pressure gives a statistically satisfactory representation of the compressibility factor when the data are treated simultaneously and a weighting factor of Pr-3/4 is used. The second virial coefficient of helium at 0° C from this investigation is 11.997±0.015 cm3 mole-1. The stated uncertainty is the random error standard deviation. Compressibility factors determined by this investigation are precise to better than 0.01 percent and are believed to be accurate to better than 0.02 percent.

Jan 1, 1969

By D. L. Nussear, W. E. Wallace, N. N. Clark, M. Gautam, G. Hong-Guang

"Results from a study directed towards identifying and measuring the mutagenicity of diesel exhaust particulate matter involved in mining exposures, especially those which may synergistically affect genotoxic hazard, are presented in this paper. Particulate matter emissions from a diesel engine, representative of the ones found in underground mines, were sampled and assayed to determine the genotoxic potential as a function of engine operating conditions. Diesel exhaust was diluted in a multi-tube mini-dilution tunnel and the particulate matter was collected on 70 mm fluorocarbon coated glass fiber filters as well as on 8"" x 10"" hi-volume filters. A six mode steady state duty cycle was used to relate engine operating conditions to the mutagenicity potential.Protocols developed for using a primary component of pulmonary surfactant as a medium for collecting and applying respirable particulate material to cells for mutagenicity testing offer a true representation of in-vivo delivery of such respired aerosols to pulmonary cells and the genetic material within . The surfactant dispersion technique is discussed in this paper. Methods have been developed to sample and assay the diesel soot and diesel soot/mineral dust complexes which would not compromise the surface and physical properties of the particulate material."

Nov 1, 1995

By L. G. Marshall

This report is one of a series published by the Federal Bureau of Mines describing mining methods and performance at individual operations throughout the United States. The objective of these papers is to promote development and conservation of our mineral resources by disseminating reliable technological information on mining methods, practices, and results that may be applied to the engineering analysis and solution of mining problems. SUMMARY Operation of a limestone quarry producing flux for the steel industry and crushed stone for production of concrete is described in this report. The deposit being mined is a flat-lying limestone formation under a thin overburden 2 to 25 feet thick. The height of the quarry face varies from 9 to 60 feet, averaging 40 feet. Production rate ranges from 4.5 to 5 million long tons per year.

Jan 1, 1959

By D. L. Nussear, W. E. Wallace, N. Clark, M. Gautaum, G. Hong-Guang

"Results of a research effort directed towards identifying and measuring the genotoxic properties of respirable particulate matter involved in mining exposures, especially those which may synergistically affect genotoxic hazard, are presented. Particulate matter emissions from a direct injection diesel engine have been sampled and assayed to determine the genotoxic potential as a function of engine operating conditions. Diesel exhaust from a caterpillar 3304 diesel engine, representative of the ones found in underground mines, rated 100 hp at 2200 rpm is diluted in a multi-tube mini-dilution tunnel and the particulate matter is collected on 70 mm fluorocarbon coated glass fiber filters as well as on S"" x 10"" hi-volume filters. A six mode steady state duty cycle was used to relate engine operating conditions to the genotoxic potential. Results to-date on diesel exhaust have indicated that use of a primary component of pulmonary surfactant as a medium for collecting and applying respirable particulate material to cells for mutagenicity testing offers a true representation of in-vivo delivery of such respired aerosols to pulmonary cells and the genetic material within. Protocols have been developed to sample and assay the diesel soot and diesel soot/mineral dust complexes which would not compromise the surf ace and physical properties of the particulate material. Evidence has been gathered to show that diesel soot expresses mutagenic potential as dispersions in DPL in the Ames tests as well as sister chromatid exchange activity in the animal lung fibroblast ·derived V79 cell line. The results are comparable to the standard solvent extraction procedure. INTRODUCTIONDiesel engines are primarily associated with transportation; however, they are also very common in the work place. Of particular concern is the use of diesel engines in mining operations. Currently there are 1,950 diesel machines working in underground coal mines throughout the country. These units are used in 151 mines encompassing nine different states (MSHA, 1991). It is believed the use of diesel powered equipment has contributed to higher productivity in these mines. However, the exhaust from diesel engines operated in underground mines has been a subject of concern during the past decade because of its suspected relationship with health aspects. The particulate matter generated by the diesel engine is of particular concern."

Mar 1, 1992

By W. Dan Walker

In an effort to keep mine hoist accidents to a minimum and to impart to managers and workers the essential elements that enter into safe installation and maintenance of hoisting equipment, the Bureau of Mines presents this Information Circular as a guide. Hoisting of men and materials is an essential operation in many mines and has become so commonplace that some persons are likely to ignore day-to-day inspections or become lax in the operating phases. With proper maintenance and operation, hoists can be exceptionally safe. However, lack of strict attention can invite tragedy or costly shutdowns.

Jan 1, 1961

By Ronald T. Mayerle

There are no producing or developing mines in the Rattlesnake RARE II area. Specific areas with mineral occurences are prospects for: 1) stratabound copper and silver in Belt sedimentary rocks on the northwest border of the study area; 2) base metal sulfides, in thin veins and shear zones in Belt sedimentary rock, and diabase dikes and adjacent metasedimentary rocks in the southern part of the study area; 3) barite in sedimentary rocks near Rattlesnake Creek and Sheep Mountain; 4) limestone near Rattlesnake Creek and Blue Point; and 5) silica in quartz veins near the headwaters of Rattlesnake Creek and Sanders Lake. Stone, sand and gravel suitable for construction material are in the study area; however, equal or better quality deposits are common throughout the region. The RARE II area has no known oil and gas, coal, or geothermal energy deposits.

Jan 1, 1983

By Lester G. Morrell

THE WORLDWIDE economic expansion that has characterized the first 3 years of the 1960's continued through 1964 and was reflected in North America by strength in the industrial economy of the United States, which again was dominant. Advances in production were recorded in virtually all industries, including the mineral industry; 1964 mineral production established a new high, 5.4 percent above the previous peak recorded in 1963. However, the percentage increase in value of North American mineral production was slightly below overall economic growth. For industry in general, consumer demand held firm throughout the year and overall commodity prices averaged 2 percent higher than in 1963. Wages and salary payments also were up. With the single exception of the dock strike in the United States, the year was free of serious labor troubles and unemployment in both Canada and the States was at a low level. Despite the Viet-Nam situation, relatively tranquil international relations contributed to the forward movement of North American business. Total gross national product (GNP) for Canada and United States, in current dollars, was estimated at US$672.2 billion; 6.8 percent above the previous year's figure. Combined national income in 1964 amounted to US$546.9 billion, which was nearly 7.0 percent more than in 1963. In 1964, gains were recorded in each of more than 50 metals, nonmetals, and fuels commodities that comprise the North American output. The greatest category increase was 13 percent in metals, which was in part attributable to the 14 percent rise to a new record in value of iron and steel in United States, a 29 percent higher value of Canadian iron ore and a 57 percent rise in Canadian zinc. Despite a moderate decline in prices of iron ore and iron and steel products, generally favorable markets and rising prices for metallic ores and metals were a stimulant to the metals industry. Nonmetallic materials, with a total value in excess of US$5.25 billion were 7.3 percent higher than in 1963. High levels of highway and building construction and expanding demand for fertilizers and chemicals continued throughout the year. Noteworthy output increases were recorded for lime,

Jan 1, 1966

By R. Barany

The heats of formation of goethite, ferrous vanadate, and manganese molybdate at 298.15° K were determined by solution calorimetry. For formation from the elements, the heat values were -133.7 ±0.3 kcal/mole for goethite, -453.8 ±0.5 kcal/mole for ferrous vanadate, and -284.8 ±0.2 kcal/mole for manganese molybdate. For formation from the oxides, the heat values were -0.9 ±0.1 kca1/mole for goethite, -19.4 ±0.3 kca1/mole for ferrous vanadate, and -14.6 ±O.l kcal/mole for manganese molybdate.

Jan 1, 1965

By R. Barany

The heats of formation of gehlenite and talc were determined by hydro-fluoric acid solution calorimetry. The results are reported in terms of the constituent oxides (?H298.15 = -31.1 ± 0.5 kcal/mole for gehlenite and ?H298.15 = -44.9 ± 0.3 kcal/mole for talc) and in terms of the constituent elements (?H298.15 = -952.8 ± 0.7 kcal/mole for gehlenite and ?H298.15 -1,415.5 ± 1.4 kcal/mole for talc).

Jan 1, 1963

The Bureau of Mines equipped a longwall shearer with a water-jet-assisted cutting system and measured dust levels during the cutting of a simulated coal block. The block was cut dry, at a conventional water spray pressure of 190 psi, and with water-jet-assisted cutting pressures ranging from 1,000 to 6,000 psi. At water pressures of 3,000 psi and higher, dust concentrations were reduced by as much as 85 pct via water-jet-assisted cutting in comparison with conventional water sprays. This reduction was achieved without any increase in the water flow rate.

Jan 1, 1986

Three types of communication systems have become popular in solving communication requirements underground: Loud-speaking pager phones, carrier current phones, and magneto ringing phones. Basically, all three are simply single-channel party line systems. Although these systems are quite reliable, the single channel creates a variety of problems. For example- 1. Since no call is confidential, messages are sometimes purposely made vague, especially if accidents or safety topics are being discussed. 2. A potential user must literally "wait in line" until the channel becomes clear for his use; thus, when foremen have to wait to call in reports or supply requests, this single chan-nel creates a serious productivity bottleneck. 3. In many large mines, there are independent branch lines that must be tied together by a dispatcher, adding further delays to the system. To solve these problems, some mines have installed other phone systems-mostly commercial dial phones in industrial enclosures that offer extra channel capacity and private line features. Others have installed a system that combines both dial- and page-phone features in a single unit. Although these do represent improvements, they do not truly solve the overall problems that face modern mines. Besides extra channels, a communication system should have the following features to enhance productivity and safety: 1. A means of paging a roving miner to alert him that he is wanted on the phone. 2. Wireless-to-wired system interconnects by which a miner can talk on the wired phone system by using a remote portable radio. 3. Remote monitors that alert personnel when there is a toxic or explosive gas buildup. 4. Control interfaces that allow remote control of fans, pumps, or other devices. 5. Transmitters and receivers that can serve as emergency links. 6. Loopback that allows an alternate path of communications if the main path is cut. This chapter focuses on equipment and methods to meet the special communication needs of individuals in various places of the underground mine. The communication requirements can be broken down into four categories: 1. The mine entrance (shaft communication). 2. Permanent and semipermanent locations (shop areas, lunchroom, crusher stations, etc.). 3. Mining areas (the room-and-pillar sections, longwall faces, block caving areas, etc.). 4. Haulageways (tracked trolley haulage, diesel, belt haulage). Methods of implementing systems to meet the communication needs of these areas are described in sections 3.2 through 3.5. Section 3.6 discusses methods of satisfying special communication requirements that exist. Major topics in this category include communications with roving personnel, the isolated miner, and motorman-to-snapper communications. Emergency communication systems are described in section 3.7.Detecting and

Jan 1, 1984

By V. B. Dale

This paper is one of a Federal Bureau of Mines series covering the mineral resources of the Nation. It briefly describes most of the tungsten deposits in Cochise, Pima, and Santa Cruz Counties, Ariz. Most of the descriptions are from field examinations by the two senior writers, prior to July 1957. Wolframite first was identified in Arizona in 1896 by W. P. Blake, Territorial Geologist. Tungsten mining began about 1900 in the Little Dragoon deposits of Cochise County, and about 1901 in Las Guijas district of Pima County. The price history of tungsten is an erratic one; consequently, production has been erratic. Prices rise during wars and periods of national preparedness. Production of tungsten ore was stimulated greatly by a Government purchasing program, announced on May 10, 1951, wherein the Government agreed to purchase standard-grade tungsten concentrates at $63 per short ton unit5/ for 5 years or until 1,468,750 units were purchased. This was later increased to 3,000,000 units, and after this amount had been purchased in June 1956, the purchase of an additional 1,500,000 units was authorized. Government purchase, however, was suspended in December 1956 before completion of this latter program, and the price of tungsten concentrates declined sharply. The price had dropped to $15 per short ton unit, duty extra,6/ by the last part of July 1957.

Jan 1, 1960

By H. H. Fields, T. W. Goodman, Joseph Cervik

The Bureau of Mines conducted research to determine the effectiveness of long holes drilled in solid virgin coal in degasifying an area of the Pitts- burgh coalbed showing that horizontal holes drilled into a virgin coalbed from the bottom of any shaft will effectively remove methane gas in commercial quantities from the Pittsburgh coalbed. The in situ pressure at a depth of 214 feet into the coalbed and the average gas and water flows from the five degasification holes were 3 lb/in2 gage and 860,000 ft3/d and 1.7 gal/min, respectively. On June 19, 1975, after 593 days of degasification, a compressor was installed and pipeline quality gas was introduced into a commercial pipeline. As of June 1, 1976, after 1,022 days of degasification, over 753 million cubic feet of gas had been drained and 117 million cubic feet of gas had been purchased by the gas company for use in the local community of Wadestown, W. Va. The gas drained to date is six times the gas estimated to be in the area subtended by the holes. Methane emissions at the working face of 1 West mains, Federal No. 2 mine has been reduced by 50 pct, proving the value of methane drainage by horizontal degasification holes drilled from shaft bottoms ahead of mining.

Jan 1, 1976

By Annie G. Smelley

The Bureau of Mines, U.S. Department of the Interior, as part of its mission to effect pollution abatement, conducted research to devise means for disposing of phosphatic clay wastes and reclaiming mined land. Part of the investigation was performed in a cooperative research project with 10 phosphate companies in Florida. The colloidal properties of the phosphatic clay suspensions, called slimes, make them difficult to dewater and dispose of without impoundment storage aboveground. Various reagents to flocculate and dewater these plant wastes were evaluated, and a polyethylene oxide polymer was found to function in a specialized flocculation dewatering technique. The flocculation dewatering method was investigated in bench-scale batch tests and applied in continuous dewatering tests using standard mineral-processing equipment. In continuous tests at feed rates of up to 58 liters per minute, wastes at 4 percent solids were dewatered to about 20 percent solids. About 0.8 kilogram of polymer was used for each metric ton of dry waste clay solids; processing time was about 4 minutes. Requirements for the treatment system are (1) proper mixing of the clay-waste feed and flocculant, (2) rapid removal of water as it is released, and (3) physical manipulation to promote cohesion of solids.

Jan 1, 1979

By Lucien Eaton

This paper describing the mining practices at Mine No. 2 of the Marquette Range, Michigan is one of a series being prepared by the Bureau of Mines on mining practices, methods, and costs in the various minim; districts of the United States. The publication, of this information should be of interest to the industry at large and the exchange of ideas thereby made possible should be of economic value to operators in all harts of the country. ACKNOWLEDGMENTS The author is indebted to the superintendent, engineer, and mining captain of the property discussed in this paper for much of the information presented. The geological classification is taken from publications of the U. S. Geological purvey.

Jan 1, 1929

By Richard F. Hewlett

Use of digital computers makes possible a more efficient and complete analysis of data from a mineral deposit . This computer program was written and used during an investigation into the efficiency of methods of computing grade and tonnage of ore , wherein it was necessary to make repeated computations involving different combinations of data . This investigation was part of a continuing program of sampling methods research at the Bureau's Denver Mining Research Center.2-4 This program is designed to compute tonnage and average grade for 40 cutoff grades using either the statistical or polygonal methods . tational rate is from 200 ( input bound ) to 1,400 assays per minute , depending on the use of either individual ( one assay per card ) assay- interval length or

Jan 1, 1963

By H. H. Fields, Stephen Krickovic, M. G. Zabetakis, Albert Sainato

The Bureau of Mines is in the process of degasifying a virgin area in northern West Virginia from the base of an 839-foot -deep vertical borehole. An in situ gas pressure hole 199 feet long, and seven degasification holes ranging in depth from 500 to 850 feet (average 618 feet) were drilled in an 8-foot-thick virgin Pittsburgh coalbed from the enlarged (14-foot-diameter) bottom of this borehole. The in situ pressure at the back end of the hole and the range of gas and water flows from degasification holes as they were completed and closed off were 203 psi, 79,000 to 257,000 cfd (average 160,000 cfd), and 5 to 8 gpm per hole (average 6.8 gpm), respectively. Twenty-four hours after the seven holes were connected through individual water traps to a common collector for natural venting of the gas through pipes to the atmosphere, the total gas and water flows and the in situ pressure dropped, respectively, to 971,000 cfd, 1.3 gpm, and 18 psi. Eighty days later the corresponding values dropped to 529,000 cfd, 0.50 gpm, and 13 psi. After 180 days of degasification, 91 million cubic feet of gas had been removed from the affected virgin area. This represents 60 to 70 percent of the gas calculated to be contained in the area of coal affected by the holes.

Jan 1, 1973

By S. J. Page, W. E. Wallace, P. Bolsaitis, D. Eppelsheimer, M. J. Keane, J. Poston, J. Harrison

"Respirable-sized dust particles from a clay mine and mill were examined for aluminium and silicon content by scanning electron microscopy-energy dispersive X-ray analysis at incident electron energies of 5--20 keV. Most of the high silica content particles, those which had a silicon to silicon plus aluminium signal fraction, measured at 20 ke V, of0.9 or greater, showed a decrease in the silicon fraction of signal with decreasing incident electron energy, down to values of between 0.6 and 0,8 at 5 keV: this decrease was a function of particle size and composition. Simple models for silicon fractiol) of signal vs incident electron voltage suggest this behavour is due to a heterogeneous particle structure in which an aluminosilicate coating occludes the surface of a silica particle core. The coating survives incubation in a major component of pulmonary surfactant.INTRODUCTIONMINING and some other dusty workplace atmospheres are monitored for respirable dust and quartz dust for purposes of occupational health protection, respirable quartz dust being a known cause of pulmonary disease. Respirable quartz exposure data are acquired also for epidemiological research on the correlation of pulmonary disease prevalence with respirable dust composition and concentration. For these purposes quartz content often is measured on collected dust samples by X-ray diffraction or in spectroscopy. Scanning electron microscopy-energy dispersive X-ray analysis spectrometry (SEM-EDX) is also used. The first two methods measure the bulk composition of a multi-particle dust sample; SEM-EDX measures the elemental composition of single ·particles. These methods as typically applied, including SEM-EDX with a 20-30 kilo-electron volt (keV) electron beam accelerating potential, do not distinguish homogeneous distribution of impurities in a particle from possible heterogeneous surface distribution. These measurements of quartz content are not always accurate predictors of the prevalence of dust-induced disease (ROBOCK and BAUER, 1990), which implies that the biologically available quartz surface may not be equivalent to conventionally measured quartz content of respirable dust in some exposure settings. Using a minor modification of conventional scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX) protocols on samples of settled and airborne dust from a clay mine and mill we have detected heterogeneity with depth for aluminium impurity in high silica content particles, indicating that some of the quartz or 'free silica' respirable particles of the dust are aluminosilicate occluded. Coatings were not removed by incubation of the dust in a surrogate pulmonary hypophase surfactant fluid."

Jan 1, 1990

The following are abstracts from papers presented at the 4th Symposium on Respirable Dust in the Mineral Industries and· were produced through research funding under the Generic Mineral Technology Center for Respirable Dust. Full articles appear in the proceedings published in July 1996 in Applied Occupational and Environmental Hygiene. (Volume 11, Number 7). The two addresses included in the proceedings point to the progress, prospects, problems, and perspectives on control of respirable dust and dust-related disease in the mineral industries. The symposium papers deal with respirable dust issues that are longstanding such as characterization, health effects, control of airborne coal dust, new and emerging issues such as iron toxicity, diesel particulates, and sampling. The papers were grouped into the following topics: continuous dust monitoring, encompassing the development of a fixed-site monitor that will provide continuous information on instantaneous and time-weighted respirable dust concentrations; mechanisms involved in the generation of dusts in mine environments, important for dust control at the source; characterization and control of diesel emissions (particularly diesel particulates) in mine atmospheres; mining systems effects and models; dust control in mine working faces and in milling environments; characterization of the physical, chemical mineralogical, and biological properties of the dust and their relevance to health effects and sampling; dust-lung interactions, encompassing results from several biomedical studies dealing with acute and chronic inhalation of airborne dusts and associated lung responses; the role of iron in causing lung injury; and therapeutic strategies for ·the control of pulmonary disease. All papers submitted to the organizers were peer-reviewed. In the proceedings, we have not differentiated among the platform and poster papers; rather, they have been grouped into the above topical areas. Taken together, these papers reveal significant progress in the control of dust generation, characterization of dust, understanding of dust-lung interaction, and mining and milling practices to reduce dust exposure - all essential for reducing dust-related occupational hazards at the workplace.

Jan 1, 1998

By R. E. Lindstrom

Electrooxidation techniques were investigated on a bench scale by the Bureau of Mines to determine the applicability of the process for extracting molybdenum and rhenium from low-grade molybdenite concentrates. Parameters affecting the extraction, such as pulp density, power consumption, reagent requirements for pH control, and electrolytic cell configuration, were studied. Molybdenum and rhenium extractions of 98 to 99 percent were achieved from several concentrates containing 4.76 to 28.6 percent molybdenum and 180 ppm to 1,000 ppm rhenium. Optimum results were obtained by maintaining pH values between 5.5 and 7.0 during electrolysis and allowing the final pH to rise to about 8.2. Reagent consumption was 4 to 6 pounds of sodium carbonate per pound of molybdenum extracted. The power consumption declined from a range of 12 to 25 kilowatt hours per pound of molybdenum extracted with immersion electrodes to 9.7 kilowatt hours with a bipolar flow-through cell; however, molybdenum extraction was independent of cell configuration.

Jan 1, 1973