Search Documents

By Stephen C. Tadolini

The Bureau of Mines conducted field investigations in two underground mines to determine the actual loads to which bearing plates were subjected when installed in conjunction with full-column resin-grouted bolts and the roof movements generated by the applied loads. Measured loads indicate that the bearing plate is an integral part of the support system. Vertical displacement gauges installed to monitor roof displacements in the test sites show that the highest degrees of loading occur in conjunction with the largest amounts of movement.

Jan 1, 1986

By W. W. Adams

"The third annual safety contest for plants producing sand and gravel, which was conducted in 1911 by the United States Bureau of Mines in cooperation with the National Sand and Gravel Association, registered further progress in safety as compared with the two previous annual contests. Both the accident-frequency rate and the accident-severity rate were reduced.The period covered was the calendar year 1931; sixty plants participated, and 17 States were represented by the participating companies.The contest covered accidents and man-hours worked by all men at the participating plant who were employed by the same company; and it included work up to the point of delivery of the material directly to the consumer or to an independent agency of transportation--in other words, to the point of relinquishment of control of the material by the producer.The purpose of the yearly contests for producers of sand and gravel is to aid in the promotion of safety among the employees and in the reduction of accident costs to the companies. The contests develop friendly rivalry among the various plants and among the employees of individual plant in a concerted effort to prevent accidents.Two safety trophies are awarded annually, both of which are provided by Rock Products magazine. One of the trophies is for the host safety record among plants that were in operation the contest year 100,000 or more man-hours; the other trophy is for the best among plants that were in operation lees than 100,000 man-hours. Awards and the relative standing of the various plants are based upon statistical compilation by the Bureau of Mines of accident reports and employment reports furnished by the enrolled companies. are summarized at the close of each year, and the summaries are submitted to each company concerned for certification as to the accuracy of the summary and the completeness of the company's reports from which the summary was prepared. When the summery is returned signed by an official of the company, the records are considered to be a trustworthy basis for determining the relative standing of the various plants. The position of each plant is determined by its accident-severity rate; that is, the number of days of disability resulting from accidents for each 1,000 men-hours of work done by all employees at the plant."

Aug 1, 1932

By R. D. Rosenkranz

The Bureau of Mines has investigated the availability of copper from 272 deposits in market economy countries. The deposits studied have demonstrated resources totaling 413 million metric tons of contained copper and account for more than 90 pct of the reserve base for market economy countries. Using data gathered as part of its Minerals Availability Program, the Bureau performed geologic, engineering, and economic evaluations in order to determine the copper production potential of each deposit. At the 1981 copper market price of $0.85/lb, the deposits studied could economically produce an estimated 88 million metric tons of copper (allowing for profit computed at a 15-pct rate of return), primarily from mines operating at the time of the study (1981). At this price, producing mines in market economy countries could economically produce only 2.1 million metric tons of refined copper per year. However, actual 1981 production was 6.2 million metric tons, indicating that many mines continued to operate even though they were unable to cover all production costs. For U.S. producing mines, the estimated average cost of production per pound (including profit at a 15-pct rate of return) was $0.15 higher than the average cost in other market economy countries.

Jan 1, 1983

By Earl T. Hayes

For several years the Northwest Electrodevelopment Laboratory of the Bureau of Mines, in cooperation with the Air Materiel Command, U. S. Air Force, has been studying zirconium alloys. A preliminary survey of these alloys has been completed and reported as a Bureau of Mines Report of Investigations. 4/ Originally the purpose was to determine the suitability of zirconium alloys in medium-temperature applications. However, data also were obtained on other properties of these alloys, and later the scope was broadened to include amore detailed investigation of a selected group. The zirconium-titanium system was one of those chosen. The Bureau of Mines has been instrumental in the commercial development of both of these metals and has constructed pilot plants for the production of titanium at Boulder City, Nev., and for zirconium at Albany, Oreg. Both elements are in subgroup A, fourth series of the periodic table, and therefore have many properties in common. Since both have similar atomic structures and lattice dimensions the possibility of extended mutual solubility seemed likely. Inc transition-point diagram of Fast indicated that the two metals are completely miscible in all proportions in both the alpha and beta forms.

Jan 1, 1951

By Gary E. Sherman

The Bureau of Mines estimated the remaining lode gold endowment of eight mining districts in Alaska using historic production data. A log-arithmic model of cumulative tonnage of ore processed versus cumulative grade was applied to the following districts: Chichagof, Fairbanks, Homer, Hope-Seward, Juneau, Ketchikan, Prince William Sound, and Willow Creek. To assess the remaining endowment, a computerized production data base was compiled from Bureau records. These data were aggregated in 5-yr intervals for each district. Data were sorted in order of declining grade, and log cumulative grade was plotted against log cumulative tonnage. Linear regression was performed on the data for each district. The linear equation for each curve was used to predict remaining endowment at a limiting mining grade. Based on conservative extrapolation of the grade-tonnage curves, a substantial total endowment of 8,415,100 tr oz of gold remains in the eight districts. The districts with the greatest remaining endowment are the Juneau, Chichagof, Fairbanks, and Willow Creek Districts.

Jan 1, 1987

By Wilbert J. Huff

For the past 9 years , the technical studies conducted by the Explosives Division of this Bureau have been summarized in a series of reports issued annually . The following account presents investigations undertaken from July 1 , 1943 , to June 30 , 1944. The work is detailed under a number of main headings corresponding to the organizational structure of the Division , the various activities being under the immediate direction of unit chiefs , who report directly to the author . Specific credit , however , is due to the individual unit leader and his assistants .

Jan 1, 1945

By Raymond B. Ladoo

In order to obtain comprehensive and authentic information on fluorspar mining in the western States , the writer, together with and at the request of representatives of some of the largest fluorspar producers of the Illinois - Kentucky district , spent the month of April , 1922 , in examining all we stem fluorspar deposits ( of which record was available ) believed to be of possible commercial importance .

May 1, 1923

By Charles L. Ross

A successful placer mine is being operated by the E. T. Fisher Co. on Rock Creek in the South Pass mining district at Atlantic City, Wyo. About 2,800 cubic yards of gravel is dug daily by a gasoline-driven dragline shovel with a 1 1/4-yard bucket and washed in a movable plant with a gold-dredge trommel and standard-dredge sluice boxes; the total cost is about 12 cents per cubic yard. The gold-bearing gravel occupies a narrow valley between two low ranges, of hills. The ground is covered by brush and willows, which are cleared of in the fall by burning after the leaves have dried. The elevation at the mine is 7,600 feet above sea level.

Jan 1, 1935

By B. I. Ferber

Toxic and explosive atmospheres are discussed, along with some of the instruments commercially available for their detection. No attempt has been made to evaluate the accuracy of anyone device. This circular has been prepared primarily to aid mine inspectors in selecting suitable instruments for underground gas detection.

Jan 1, 1972

By R. L. Loofbourow

The adjacent towns of Rouyn and Noranda, centers of the Rouyn mining district of western Quebec, are 360 miles by air line almost duo north of Toronto. Rouyn is reached from the main lines of the Canadian National Railways and the Canadian Pacific Railway at North Bay, Ontario, by the Temiskaming & Northern Ontario Railway and its subsidiary, the Nipissing Central Railway. Noranda is the southwestern terminus of a branch from the Canadian National Railway between Winnipeg and Quebec. The Rouyn mining district is a part of a mineralized zone that has been traced for a distance of 140 miles from Kirkland Lake in Ontario eastward into the Province of Quebec to the Pascalis district. From Rouyn the mine is 5 miler almost duo south over a gravel rend built by the company with assistance from the Province of Quebec.

Jan 1, 1933

By Thomas O. Llewellyn

This U.S. Bureau of Mines (USBM) report presents a concise review on sources, processes, supply, and historical use patterns of domestic cadmium. It also covers a preliminary estimated cadmium material flow for the year 1989. This preliminary study contains information on cadmium and cadmium-bearing products in the United States. The data in this report were obtained from both published and/or unpublished sources of information. However, in order to estimate the fate of cadmium in each operation or application stage, some assumptions, judgments, and correlations were made by the USBM in an attempt to determine the material flows losses.

Jan 1, 1994

By Ronald M. Van Noy

A reconnaissance study of kyanite-group mineral deposits in the Northwest has revealed large exploitable reserves of the mullite-forming raw materials in the Woodrat Mountain and Goat Mountain districts of north-central Idaho. Potential coproducts or byproducts are garnet and muscovite mica. The Woodrat Mountain district contains garnet-kyanite-mica schist, which has been traced for 6 miles and may extend farther. Surface samples average 29 percent kyanite and contain up to 15 percent garnet. Inferred reserves of strippable ore with a low waste-to-ore ratio, and containing more than 15 percent kyanite, are more than 3 billion short tons. The Goat Mountain district contains several kyanite-mineral zones. Samples of the richest zones average from 10 to 20 percent kyanite minerals and represent about 200 million short tons of strippable rock. Beneficiation tests indicate that the kyanite minerals and garnet can be concentrated by a combination of gravity, flotation, and electromagnetic methods. Reserves in these deposits are sufficient to satisfy any foreseeable domestic and export demand. However, the freight tariff to reach the nearest major users of kyanite (located in the Midwest) has discouraged development of western kyanite resources. Western demand of a magnitude to support a moderate to large milling operation has not yet been developed. However, there is some foreign market potential. If a garnet byproduct could be prepared and sold for coated abrasive products or as grinding grains, an offset possibly could be gained to a por¬tion of the mining and milling costs for the Pacific Northwest producer. Such byproduct values would offer a means for expanding the geographic market areas as well as the regional market potential.

Jan 1, 1970

By D. Harrington

Fire is always a serious-menace, whether in a residential or in an industrial region; in wartime it is particularly damaging in an industrial plant. The mining industry is especially vulnerable, as its plants are generally more or less isolated front centers of population and do not have access to modern fire-fighting equipment; moreover, owing to the transitory rapture of most mines, their surface structures; are often relatively flimsy and flammable.. Trained firemen seldom are available at or near mining plants to teach the fundamentals of fire-fighting to local fire brigades, with the result that efficiency in combating actual fires is lacking. Often the attitude "it can't happen here" is held by the management of a mining property, unless the plant has suffered a serious fire; even then lapse of time is very likely to induce forgetfulness as to the possible hazards. The necessity for producing metals for the prosecution of this war has increased management's responsibility. Whereas heretofore the loss of a plant or mill by fire meant merely monetary less to the stockholder of the company, now the national interest is affected, in that the nation suffers from loss of production of minerals indispensable for war purposes.

Jan 1, 1943

By George Saliba

This report disucsses the formulation of a mathematical model for the steering of a conveyor belt by a flat return idler and a troughed idler under various loading conditions. Significant parameters associated with belt training are identified. The generation of a skewed flat return idler model in terms of a steering force and self-aligning torque is presented. Development of the mathematical model for the flat return steering idler is illustrated for the case of no circumferential slip occurring and for the assumption of a bidirectional slip mechanism. Experimental results supporting the theoretical analysis is presented.

Jan 1, 1977

By Franklin H. Persse

The Bureau of Mines estimated reclamation costs for 13 surface coal mines in nine States west of the Missisisppi River. With the exception of the Pacific Coast coal province, at least one mine in each of the western coal provinces was studied. Cost estimates were, made using standard estimating procedures from data obtained from company records, interviews with industry personnel, and onsite observations. Estimated costs are presented in four categories which represent the four phases of mined-land reclamation: (1) Design, engineering, and overhead; (2) bond and permit fees; (3) backfilling and grading; and (4) revegetation. Estimated costs as of the first quarter of 1976 are expressed as averages and ranges in terms of per acre, per ton of coal produced, and per million Btu. Total reclamation costs ranged from $860 to $7,200 per acre, from 6 to 84 cents per ton, and from 4 to 35.3 mills per million Btu. A mine in the Northern Great Plains coal province (Region D) showed the highest per acre cost whereas mines in part of the western region of the Interior coal province (Region A) experienced the greatest per ton and per million Btu cost. The high cost of reclamation in the Western United States is reflected in the backfill in and grading category, particularly in the cost of topsoil removal and subsequent replacement as required by individual State reclamation regulations.

Jan 1, 1977

By P. M. Sullivan

A physical beneficiation flowsheet was designed by the Bureau of Mines for reclaiming and recycling metal and mineral values contained in municipal incinerator residues, and a continuous processing plant was installed. Residue samples collected from incinerators located in various parts of the country were processed at a rate of 1/2 ton per hour. Continuous screening, shredding, grinding, magnetic separation, and gravity concentration techniques were applied to produce metallic iron concentrates, clean nonferrous metal composites, clean fine glass fractions, and tine carbonaceous ash tailings. Research to develop systems for refining and upgrading the reclaimed metals and glass into marketable products is also underway. From the engineering data developed in the continuous processing plant, evaluations of the capital and operating costs for plants with capacities of 250, 400, 670, and 1,000 tons of dry incinerator residues per day were made. Research on a parallel system to separate and recover the metals, minerals, glass, paper, and plastics from raw, unburned refuse it currently underway, as are studies on the use of air classification to separate the refuse into organic and inorganic fractions.

Jan 1, 1971

By Homer J. Ballinger

During the fall of 1943 and spring of 1944, the Bureau of Mines investigated nine secondary limonite iron-ore deposits in the Williamsville district of Wayne, Butler, and Ripley counties, Mo., by rotary-bucket and power-auger drilling test pitting, and trenching. Studies on beneficiating the ores were made at Bureau laboratories. Iron ore has been mined in Missouri since 1825, and iron mining reached its greatest development between 1870 and 1890. During this period, production averaged about 250,000 tons annually.

Jan 1, 1948

Control shearer-generated airborne respirable dust on longwall mining sections. Approach Previous Bureau studies have shown that using high-pressure water can have a significant impact on the amount of airborne dust released into the face airflow while cleaning and controlling the airflow in the immediate cutting zone. The basic concept to improve the drum water spray system was to utilize high-pressure (1,200 psi) inward-facing drum sprays to improve the dust knockdown efficiency of the spray system and confine the dust to the face area. This system would minimize the exposure of the shearer operator through dust avoidance and decrease face dust levels by suppressing the amount of respirable dust that becomes airborne. System Design In-mine tests were designed to provide information that would permit evaluation of the operation with different spray orientations and water spray pressures. This was achieved by comparison with a conventional baseline wet-cutting system consisting of 26 low-pressure bit sprays, located on the hit blocks to provide pick-point flushing. Total drum water flow was 60 gpm and was maintained continuously throughout all tests. The high-pressure inward-facing drum water spray system consisted of sprays located in each bit block, oriented 15° and 30° toward the face. The inward-facing water spray system was operated at either 800 or 1,200 psi.

Jan 1, 1989

By William P. Diamond

This report presents results of a cooperative research project between the U.S. Bureau of Mines and BethEnergy Mines, Inc. Four coreholes (two before mining and two after mining) were drilled at a longwall mine operating in the Lower Kittanning Coalbed to obtain coal and rock samples from over-lying strata to determine their gas content at various times in the mining cycle. The results of those tests indicate that 91 pct of the gas removed from the overlying strata came from coalbeds. Material balance calculations were made to compare the volume of gas produced both from gob gas vent holes drilled on the panel and gas removed by the mine's ventilation system with the volume of gas removed from strata directly overlying the panel to a height of 275 ft. This analysis indicates that only 40 pct of the total gas produced from the panel actually came from the strata directly overlying the panel. The remaining volume of gas production probably migrated to the longwall gob from overlying, and perhaps underlying, strata immediately adjacent to the panel and perhaps from greater distances downdip because of the establishment of a long-term pressure gradient in the study area.

Jan 1, 2010

By W. W. Adams

"The National Safety Competition of 1930, the seventh annual contest conducted by the United States Bureau of Mines to promote safety in the mines and quarries of the United States, has been concluded, and the five winners of the bronze trophies, The Sentinels of Safety,' which are provided by the Explosives Engineer magazine and awarded annually for the most excellent safety records, have been determined by the committee of award. One trophy was awarded to an anthracite mine in Pennsylvania, one to a bituminous coal mine in the same State, one to an iron-ore mine in Michigan one to a gypsum mine in Ohio, and one to an iron-ore opencut mine in Michigan.These trophies were awarded to the companies for having the smallest loss of time from accidents in proportion to the total number of man-hours worked by all employees at their mine or quarry. Honorable mention was awarded to each mine or quarry that ranked second, third, fourth, or fifth in its own ground and to all plants that were operated without a lost-time accident during the contest year. Eighty-four out of 337 plants that competed for the trophies were operated without an accident that disabled an employee beyond the day on which the accident occurred.Under the contest rules, all mines and quarries were divided into five groups, four of the groups representing different classes of underground mining operations (anthracite, bituminous coal, metallic ore, and nonmetallic mineral), and the fifth group repre-senting the quarrying or opencut mining of minerals whether metallic or nonmetallic. Twenty-seven mines were included in the anthracite group, 68 in the bituminous group, 52 in the metal group, 24 in the nonmetallic-mine group, and 166 in the quarry and opencut-mine group. The total of 337 mines and quarries was 26 more than the number of plants that completed the contest during the previous year.The committee of award which determined the winners of the contest was composed of seven members, all known throughout the mineral industry but not connected with the United States Bureau of Mines. The committee included W. H. Cameron, managing director of the National Safety Council; William Green, president of the American Federation of Labor; James F. Callbreath, Secretary of the American Mining Congress; T. T. Read, Vinton professor of mining of Columbia University and editor of Mining and Metallurgy; C. B. Huntress, executive secretary of the National Coal Association; A. J. Curtis, assistant to the general manager of the Portland Cement Association; A. T. Goldbeck, director of the bureau of engineering of the National Crushed Stone Association."

Jun 1, 1931