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The Mine Safety and Health Administration (MSHA) defines an independent contractor as any person, partnership, corporation, subsidiary of a corporation, firm, association or other organization that contracts to perform services or construction at a mine. Contractors that perform specific types of work are required to report the number of employees who work at coal mines and noncoal mines.

Jan 1, 2008

By Eugene W. Bartel

This report describes in detail the circuitry used in the Automated Time Domain Reflectometry System and the testing and modification done to the system to improve the units performance and consistency. The analog ATDR software is described and explained in detail. Also attempts to implement the same Assembly Language program in a higher level language (PLM) are documented along `h two versions of the PLM program - one which uses a data filtering approach to limit noise and another which uses data averaging to reduce noise. The field testing of the analog and digital ATDR units is described along with the hardware modifications that resulted. The analog unit has been abandoned and the digital unit adopted for most field tests. Tests indicate that the digital units are much more consistent and less confusing for the lay-person to operate. The results indicate that the it can locate an abnormality in a test cable to within 5% of the true location (provided the cable phase velocity is known). The units can consistently locate shunt type faults which are less than 300 ohms and series type faults which are greater than 30 ohms.

Jan 1, 1980

By M. C. Malamphy

A general description of the activities and results of bauxite investi-gation by the Bureau of Mines at its bauxite project in Saline and Pulaski Counties, Ark., has been given in Report of Investigations 4251. The factual data obtained during the project are reported in a series of Reports of Investigation beginning with No. 4251, of which this is the sixteenth. The data are accompanied by maps showing the location of holes drilled and the deposits developed. Each area upon which work was done is reported by half townships. Each bauxite deposit investigated was assigned a name and a number for ready reference and identification, and its location and name are shown on the appropriate half-township map. The description of each half township is followed by a description of each deposit developed in that half township. The 14 half-township maps and 77 detail maps of the bauxite deposits in this series of reports give the locations and numbers of all the holes drilled on the project, except the deep holes drilled to test the geophysical anomalies. The locations of the latter holes show on figure 13 in volume 1. The descriptions of the deposits developed are followed by complete detailed logs of the drill holes. Many of the widely spaced exploratory holes did not discover bauxite of minable thickness and grade. The pertinent information obtained from the widely spaced exploratory drill holes has been summarized and tabulated, and a table for each half township is given with the discussion covering that area.

Jan 1, 1948

By R. J. Fantel

The Bureau of Mines investigated the resources, costs, capacities, market relationships, and short- and long-run supply of phosphate rock and phosphoric acid. The 206 mines and deposits evaluated in 30 market economy countries contain an estimated 35.1 billion mt of recoverable phosphate rock (demonstrated resource level). U.S. resources are sufficient to satisfy the domestic and export markets for phosphate products well beyond the year 2000. Because of resource depletion at current producers, however, new properties (with higher cost levels) need to be developed if U.S. production levels are to be maintained. Existing worldwide capacity can satisfy expected demand through the early 1990's. Expansion at existing mines or low demand growth could mean that no new property development will be needed before the late 1990's. Worldwide, almost $8 billion could be required for development of new phosphate rock properties between now and the year 2000, given 3-pct annual growth in demand. Most properties that could develop in the 1990's would require price increases of 20 to 50 pct to break even. To earn a 15-pct rate of return on investment, prices must rise to nearly double the present level of $24 to $29 per metric ton.

Jan 1, 1988

By Merwin H. Howes

In constructing the NORAD Combat Operations Center, controlled blasting techniques were employed to achieve smooth walls and to avoid shattering the rock beyond excavation lines. Extraordinary measures were taken to stabilize the rock to permanently preserve the openings. Rock stabilization was accomplished by means of reinforced concrete and gunite linings, rock boltings, installation of chain-link fabric, and epoxy resin and cement grouting. A particular zone of weakness at a vital location was supported by exceptionally thick reinforced concrete lining, rock bolts, and cement grout.

Jan 1, 1966

By Robert T. Mann

This paper is one of a series being prepared for and published by the United States Bureau of Mines on the quarrying, crushing, and grinding of limestone for cement manufacture. These papers are designed to disseminate technical information regarding the methods used. The cost tabulations represent operating expenditures only and not total coats. It is recognized that publication of total costs might in many instances cause embarrassment to individual producers, as well as to the industry as a whole. On the other hand, operating costs are essential to the technical discussion and study of the methods employed. The attention of the reader is specifically called to this differentiation in order that no misunderstanding of the scope of the cost tabulations shall ensue. ACKNOWLEDGMENTS The author wishes to acknowledge the assistance of J. B. Thoenen, mining engineer of the Bureau of Mines, in the preparation of this paper.

Jan 1, 1933

By A. Livingston

This paper on mining practice at the Fresnillo silver mines is one of a series being prepared by the Bureau of Mines on mining practices, methods, and costs in the various mining districts of North America. Two classes of ore are produced at Fresnillo. A low-grade oxidized silver ore; end a complex-base sulphide are containing gold, silver, lead, zinc, and copper. This paper is confined to a discussion of operations relating to the production of oxidized silver ores. To date, more than 10 Million tons of this ore rave been mined. The present (June, 1931) daily production is 2,000 tons of ore, and approximately 600 men are employed in the mining operations.

Jan 1, 1932

By T. A. Sullivan

Refining in a molten salt electrolyte was investigated as a means of recovering nickel containing less than 1 percent and preferably less than 0.2 percent cobalt from nickel products containing up to 5 percent cobalt. Electrolytic separation of nick and cobalt was accomplished in a molten KCl-LiCl-NiCl2 electrolyte. Nickel containing less than 0.10 percent cobalt was routinely prepared. Factors that influenced the transfer of cobalt to the refined product were the nickel concentration of the electrolyte, the cobalt concentration of the electrolyte, the ratio of nickel to cobalt in the electrolyte, and cathode current densities. A method of recovering the cobalt from the electrolyte was developed. The possibility of preparing high-purity nickel by this process was shown, as well as the preparation of various cobalt-nickel-tungsten alloys.

Jan 1, 1968

By Mark S. Sanders

This report is a review and synthesis of the published literature dealing with personal equipment items used by low seam coal miners. This report reviews the following items of equipment: headgear, outer garments, respirators, cap lamp, gloves, knee pads, footwear, boots, helmets, ear protection, eye protection. Recommendations for further research and development are included.

Jan 1, 1978

By James C. Barker

In 1981 and 1985-1986, the Bureau of Mines conducted orientation studies of marine placer platinum-group metals (PGM). PGM are derived from the Goodnews Bay ultramafic complex and magnetic surveys show that the complex extends offshore at least four mi. The present seafloor was an emergent foreland as recently as 8000 years ago. High-energy ocean processes are transporting and depositing sediment such that PGM-bearing materials are reworked and later masked by barren littoral drift. Exploration targets include 1) placers formed since present transgression began, and 2) ancient marine and drowned fluvial deposits. Additionally, there is evidence of PGM solution transport and accretion. At least minor values of PGM in Recent lag-type placers and possible submarine strands are concentrated along an offshore scarp incised through glacial deposits into the preglacial surface between Flat Cape and Red Mountain. Other Recent PGM-bearing features include Flat Cape shoal, Chagvan Bay, Salmon River delta, and modern beaches. Ancient placers include possible N-S fluvial systems 2 to 3 mi offshore, a nearshore scarp 50 ft below sea level, and strands adjacent to projected ultramafic bedrock slopes. The existance of ancient placers is dependent on depth of glacial erosion. SEM studies show PGM are principally isoferroplatinum and osmiridium, with minor sperrylite, moncheite, and platiniridium. Gold is a co-product, and concentrates comprise chromite, ilmenite, and magnetite. Beneficiation tests successfully concentrated precious metals from natural blacksand accumulations, but failed to concentrate low-grade lag gravels.

Jan 1, 2011

By J. Ritchey

This report describes the engineering feasibility and economic advantages of using a mobile bridge-type cross-pit belt conveyor system in conjunction with a large dragline to excavate and transport spoils in a typical Western surface coal mine. The studies show that such a system could be built to survive operational and climatic mining conditions, and that its implementation would offer a reduction in both acquisition and operating costs versus conventional mining units of comparable rapacity. Reclamation costs can also be significantly reduced, and the total reclamation process accelerated, making the cross-pit conveyor system attractive to mine Owners and environmentalists alike.

Jan 1, 1976

By D. Randolph Berry

This manual was prepared to provide essential information to be used when critical decisions pertaining to mine fire recovery or other disaster situations become necessary. It is a state of the art report based upon technology and instruments developed, under a Bureau of Mines Research Contract. A detailed description of the development work and results of full-scale field testing is contained in the Technical Report, Vol. II, of USBM Contract Report H0122045, "Extinguishing Coal Mine Fires by Remote Scaling." Further research and development work has been programmed; consequently, a more complete manual providing detailed instructions and describing available instruments and equipment will be published. Those instruments and special equipment described in this manual must be considered prototype; methodology and applied technology will require special expertise. Consequently, any prospective application of this remote sealing technique will require assistance by the United States Bureau of Mines Research organization and experts from the contractor who developed the basic technology and instruments.

Jan 1, 1973

By W. W. Adams, T. D. Lawrence

"The National Safety Competition of 1938, the fourteenth of its kind conducted by the Bureau of Mines in which bronze trophies known as Sentinels of Safety are awarded to winning companies, has just been completed and the results are presented here.With 345 mines and quarries competing, more than in any previous year except 1931, the contest revealed low accident rates at many of the enrolled plants and, which is even more remarkable, it revealed 113 mines and quarries at which no lost-time accidents occurred during the contest year.The Sentinels of Safety trophies, provided by The Explosives Engineer magazine, were awarded to four underground mines, one open-pit mine, and one quarry. Each employee of the winning plant was awarded a Certificate of Honor by the Bureau of Mines in recognition of the employee's part in helping his company to win the trophy. In addition to the award of trophies, a Certificate of Honorable Mention was awarded to each of the mines and quarries in second, third, fourth, and fifth places in their respective contest groups and also to each mine and quarry that worked 30,000 or more man-hours without a lost-time accident. Ninety-two such certificates were awarded for 1938. Twenty-three other mines and quarries also operated without an accident but worked less than 30,000 man-hours, the minimum required by the contest rules for award of Certificates of Honorable Mention.Previous to 1938, five trophies were awarded annually in the National Safety Competition. For the 1938 contest a sixth trophy was provided by The Explosives Engineer so that open-pit mines and quarries, two classes of operations that previously had been included in one group in the competition, might have separate awards."

Aug 1, 1939

By K. K. Kelley

Sodium-aluminum and potassium-aluminum silicates are among the more important rock-forming minerals of the earth's crust. They also appear as constituents of some metallurgical slags and of some refractory materials. Consequently, knowledge of their thermodynamic properties is interesting and valuable from several viewpoints. This paper reports experimental determinations of the low-temperature heat capacities and entropies at 298.16° K. of albite, jadeite, and nephelite it the sodium-aluminum silicate series and of adularia, ferriferous orthoclase, leucite and kaliophilite in the potassium-aluminum silicate series. Also high-temperature heat-content and entropy increments about 298.16° K. are reported for albite, jadeite, nephelite, and carnegieite in the sodium-aluminum silicate series. Except for a few high-temperature heat-content values for albite, all these data are available for the first time.

Jan 1, 1953

By S. H. Ash

THE INUNDATION of anthracite reserves in the Eastern Middle field of Pennsylvania affects the life of the anthracite industry in this field; it also influences the economic status of people, communities, and industries that depend wholly or in part upon anthracite for their livelihood. The trends of production and of employment in the anthracite-mining industry in this field are downward, and they probably will continue in this direction. The reserves have been depleted to the extent that the end of the active life of the industry as a. major economic factor is approaching. By removing the water in those pools where it can be done economically, the future of this industry may be extended somewhat.

Jan 1, 1950

By A. B. Needham

In November 1940, the Bureau of Mines started exploration of the Three Blacks manganese properties - Black Diablo. in Pershing County and Black Eagle and Black .Rook in Lander County. The purpose was to determine possible reserves of manganese in the deposits. It is reported that a small amount of manganese was mined from the Black Diablo during World. War 1. No mining except that necessary for assessment work had been done on the Black Eagle. Shipments were being made from the Black Rock deposit to a concentrator at Vain, Nev., while the Bureau's development work was progressing. The Black Diablo deposit consists of one patented claim owned by the Charleston. Hill National Manes Co. Mary L. Clough of Winnemicca, Nev., president. The deposit is about 20 miles by a gravel and dirt road southwest of Golconda, a town on U. S. Highway 40 and the Southern Pacific Railway, Pershing County, Nev. The deposit lies at an elevation of about 5,600 feet on the east flank of the north-south trending Sonoma Range. The property was leased by Messrs. Hollis Chatwin, T. E. Chatwin, and R. H. Richards of Salt Lake City and Mammoth, Utah. The lessees installed a crusher and erected an ore bin below the open cut on the deposit and mined and, shipped about 5,000 tons of about 30 to 52 percent manganese ore to the Columbia Steel Co., Provo, Utah.

Jan 1, 1950

By Arel B. McMahan

The U.S. Bureau of Mines investigated mines, prospects, and mineralized areas in the Owlshead Mountains Wilderness Study Area (WSA) in 1982. Within the WSA, subeconomic manganese, iron, zinc, and lead resources were identified at two mines; sample analyses indicate five other mines and prospects may have gold, silver, iron, manganese, and copper resources. Three mines examined adjacent to the WSA have identified manganese and iron resources; and sample analyses indicate manganese, iron, and gypsum resources may exist at two prospects. Greatest likelihood for future identification of mineral reserves is for manganese at the Black Magic Mine in the southeast part of the WSA. The southern half of the WSA contains nearly all identified mineral resources, and properties at which sample analyses indicate additional resources. The most significant are manganese and iron resources at the Black Magic Mine in the southeastern part of the WSA; and the Ellie, New Deal, and Owl Hole Mines adjacent to that part of the area. Manganese and iron minerals filled fractures and replaced limestone in brecciated and faulted contacts with intrusive granitic rocks. In the southwest corner of the WSA, sample analyses indicate four prospects may have gold and silver resources. These precious metals are in gouge zones along contacts where diorite has intruded volcanic rocks. A small identified resource at the Kennedy Boys Lead Mine in the western part of the WSA consists of quartz veins with zinc and lead minerals along a brecciated contact between granite and limestone roof pendants.

Jan 1, 1985

By Louis A. Turnbull

An investigation of coal deposits near Cerrillos Santa Fe County, N. Mex., was undertaken 14 the Bureau of Mines in 1943 as part of a general program to determine sources of metallurgical coal for western steel plants. Almost all of the coal used for metallurgical purposes west of the Continental Divide Is mined from the Lower Sunnyside bed in, Carbon County,, Utah. Coke used in western steel plants that is produced from Lower Sunnyside a coal is weaker, structurally, than coke used elsewhere in this country. For this reason, western coal operators and steel manufacturers are anxious to develop new areas of coking coal of better quality then the coal produced from the Sunnyside bed. The objective of investigations of western coals was to (a) develop additional reserves of coking coal to supplement proved reserves in the Sunnyside bed. and (b) develop; if possible, reserves of coal with coking quantities superior to those of Lower Sunnyside

Jan 1, 1951

By Charles Will Wright

This paper is one of a series dealing with mining problems and summarizing the data contained in the Information Circulars on individual mines that have been prepared by the managers or superintendents and published by the Bureau of Mines. The purpose of this paper is to present the problems encountered in the development of an efficient mine organization and to show the means used by certain mining companies in promoting efficiency. There is also a discussion of the advantages and disadvantages of the various systems of paying and handling labor and a description of their application at the individual mines.

Jan 1, 1932

The workshop on "Cyanide Effluents from Mineral Processing' was held on February 2-3, 1982, at the U.S. Bureau of Mines, Salt Lake City Research Center, Salt Lake City, Utah. The workshop was sponsored by the minerals industry, supporting industries, the National Science Foundation, and the U.S. Bureau of Mines through the Utah Mining and Mineral Resources Research Institute, College of Mines, University of Utah Prior to the workshop, a Working Paper was prepared and delivered to the participants. This paper was used as a guide during panel discussions and forms the basis for this proceedings document. The workshop focused on use of cyanide as it relates to the gold and silver mining industry and the froth flotation processes employed by mineral mining companies. Its intent was to discuss "state of the art" technology and provide information pertinent to cyanide use in the minerals industry. No attempt was made to advocate regulatory limits or set policy governing the use of cyanide. The principal topics of discussion included- (1) the chemistry and use of cyanides; (2) control and treatment of cyanide mining wastes; (3) toxicity of mining wastes; (4) fate of cyanide in the environment; and (5) the analytical chemistry of cyanide.

Jan 1, 1983