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By Earl Redman

The Juneau Gold Belt portion of the Juneau Mining District has historically had the greatest mining and exploration activity within the district. Between 1880 and 1983, the mines within the Juneau Gold Belt produced 6.7 MM oz gold, 3.1 MM oz silver, and 45 MM lbs lead, which had a total value of about $157,000,000 at the time of production. This report summarizes Bureau of Mines work completed in 1986, the second year of the Juneau Mining District study. Fifty mines, prospects, and occurrences were examined and 638 samples were collected for analysis during 1986. Metallurgical samples were collected from seven deposits and preliminary tests of cyanide amenability have been completed for five of these. The simultaneous discovery by private industry and the Bureau of gold-bearing quartz veins cutting diorite gneiss recently exposed by the retreat of the Herbert Glacier is the most notable result of work during 1986. This location yielded gold values up to 7 oz/st.

Jan 1, 2011

Greater mining productivity requires a more efficient cutting process. The cutting force available from today?s mining machines has been optimized with respect to machine size and weight. Researchers have shown that when employing water-jet-assisted cutting, bit forces and drum torques can be reduced significantly, which may allow mining machines to become lighter and more efficient. The Bureau of Mines has initiated a program to develop a water- jet-assisted rotary cutting system using the conventional bit assisted by a directed water jet operating at moderate pressures (3,000 to 10,000 psi). This water-jet-assisted cutting system has the potential to improve cutting efficiency without increasing machine horsepower or water usage (beyond what is presently used for dust control) or requiring fundamental changes in mining practice. IR addition to improvements in productivity, other anticipated benefits of water-jet cutting include reduced generation of respirable dust, elimination of frictional ignitions, increased bit life, reduced fines, and fewer machine vibrations. The papers presented at this open industry meeting discuss the development of water-jet-assisted cutting technology and future application of this technology to a variety of mining techniques including roof drilling and longwall mining.

Jan 1, 1985

By Donald I. Bleiwas

The U.S. Bureau of Mines has evaluated the potential availability of nickel from 36 deposits or districts in 16 market-economy countries (MECs), analyzing more than 95 percent of production in those countries. This study indicates the quantity of nickel available on the basis of net production costs and total costs with a 0-pct and a 10-pct discounted cash flow rate of return (DCFROR). Costs of production are expressed in dollars per pound of recovered nickel. The study also indicates sensitivities of the cost of production to energy, labor, and other factors. The studied deposits and properties contain approximately 33 Mmt of recoverable nickel. About 26 Mmt of nickel is potentially recoverable from laterite deposits, of which 4.5 Mmt can be produced at $2.50/lb or less with a 0-pct DCFROR. Approximately 7 Mmt of nickel is potentially recoverable from sulfide deposits, of which about 6.3 Mint could be produced at $2.50/lb or less at a 0-pct DCFROR. The price of nickel averaged above $6.00/lb in 1988. Sensitivity studies performed for both laterite and sulfide deposits indicate that the total cost of producing nickel from laterites is most sensitive to increases in energy costs and that the total cost of producing nickel from sulfide deposits is most sensitive to increases in labor costs; sulfides are also affected by changes in revenues from byproducts.

Jan 1, 1991

By Robert F. Pettit

This paper on methods and costs of mining and milling iron ore at the Iron Mountain mine of Ozark Ore Co., St, Francois County, Mo., is one of a series of Bureau of Mines reports on methods, practices, and costs of mining and milling throughout the United States. The Iron Mountain operation is notable for its successful transition from open-pit to underground mining, for use underground of large earth-moving equipment, and for development of a multilevel room-and-pillar mining method. Milling methods also have undergone transitions - from hand sorting and log washing in the early days to gravity concentration. Milling ultimately may include flotation to recover additional iron from products now discarded as tailing,

Jan 1, 1957

By Albert L. Brautigam, Michael R. Yenchek, Jeffrey Shawn Peterson, James C. Cawley

The National Institute for Occupational Safety and Health investigated how the starting of induction motors may cause nuisance tripping of short-circuit protection on coal mine power systems. This research had a dual purpose: 1) to identify how motor-start waveforms differ from those for short circuits and 2) to devise a method to provide short-circuit protection without intentional time delays to account for motor starts. This technology will help ensure that surface temperatures of energized electrical apparatus will not exceed gas or dust ignition thresholds when short circuits occur.

By Forrest T. Moyer

To keep the mineral and allied industries informed of trend: in the causes of accidents and to point out the need for corrective measures, the Bureau of Mines collects, analyzes, and publishes, periodically health and safety statistics. This report includes data for 1961 on injury experience, with related employment statistics, at coal mines in the United States. These data are presented in tabular form under the following headings: General Injury Experience Tables 1 to 6: Current data on number of injuries, degree of injury, frequency and severity rates, average severity, and related employment and production data by work location.

Jan 1, 1963

By H. R. Beard

The Federal Bureau of Mines investigated the absorption of radium and thorium from waste uranium leach liquor by clays and other materials. This work was conducted in support of the Bureau's goal of minimizing the environ¬mental conflicts, impacts, and occupational hazards Associated with mining and mineral processing operations. Tailings and soil samples from Wyoming and Utah were contacted with tailings liquors to determine the degree of absorp¬tion. Absorption ranged from 0 to 99 percent for radium and from 0 to 31 per¬cent for thorium. Some samples, which readily absorbed radium, were contacted with various salt solutions that could be present in tailings solutions to determine their effectiveness as desorbents. The desorption of radium ranged from 0.06 to 100 percent. An alpha-spectrometric method was used to determine the radium and thorium, concentrations in the solutions and the solids.

Jan 1, 1979

By J. R. Thoenen

In the summer of 1937 the authors began a series of time studies of the various processes employed in' the production of crashed stone. These studies, made at quarries situated in the eastern and southeastern parts of the United States, have not been completed, but to make results available to the industry as early as possible, it was decided to publish summarizes of the studies made to January 1, 1939, as a series of progress reports. The first of these dealt with power-shovel loading and was issued as Report of Investigations 3461 in September 1939. The second, issued in September 1939 as Report of Investigations 3467, dealt with quarry haulage. The present report discusses analyses of time studies of primary drilling a t the same group of quarries. OBJECT OF STUDY Pressure of business problems frequently requires the entire attention of quarry management, and in consequence internal plant economies often are neglected. Also, operating officials absorbed in their local problems are prone to overlook possible economies that would attract attention immediately were they critically examining another plant. The authors felt that technical studies at a number of plants, made by impartial engineers, might disclose opportunities to reduce costs or improve efficiency in internal plant processes.

Jan 1, 1940

By J. E. Crawshaw

"The few previous observations of the effect of turbulence on limits of inflammability have been made on a small scale in turbulence produced either by a fan or by movement of the mixture.By a suitable amount of turbulence from a fan the lower limit of methane was 5 per cent as compared with 5 per cent observed for quiescent mixtures in the same vessel.3 With a streaming movement of the gas mixture within the range of speed from 35 to 65 centimeters per second (69 to 128 feet a minute) the lower limit was approximately 5 percent,4 For a quiescent mixture of ethane the lower limit was 3.10 per cent ethane, but with fan running at a moderate speed a 3 per cent mixture exploded.5The object of the tests herein reported was (1) to determine the lower limit of natural gas in a mixture of natural gas and air Which would be ignited and propagate violently when the turbulence was produced by explosives fired from a cannon into the mixture; (2) to observe the behavior when the mixture contained less than this low limit; and (3) to determine how turbulence produced by a fan affects thin limit.Four series of tests were run, three of which were to determine the effect of different sources of ignition: Tests with (1) an electric igniter; (2) 3F black blasting powder stemmed with 2 pounds of dry fire clay stemming used to ignite the mixture, and (3) 40 per cent straight nitroglycerin dynamite unstemmed. The fourth was made to study the effect of turbulence produced by a two-speed electric fan, using an electric igniter as the source of ignition.In both series of tests with explosives, charges of 50 and 200 were used to determine the effect of increased quantity of explosives on the lower limit of natural gas."

Jul 1, 1930

By V. Ferrari

This report documents the three-phase program to design, fabricate, test, and demonstrate economical and practical methods of reducing noise levels on underground coal mining portal buses (mantrip vehicles). The noise-control treatments applied to a production-model portal bus were as follows: ? Wheel/rail vibrations were isolated from the vehicle frame by inserting elastomeric materials between suspension components. ? Vibration-induced noise was reduced by replacing all large sheet metal panels (except floor plates) with damped steel panels. ? Motor noise was reduced by tight-fitting covers made from damped steel and lined with sound-absorbing material, and by elastomeric motor mounts. ? The standard spur gears used in the traction drive system were replaced with helical gearsets. The program achieved the goal of reducing the average sound-level to below 85 dBA for typical operating conditions.

Jan 1, 1981

By Robert D. Ewing

The computer program described in this user's guide provides for the static, three-dimensional, linear and nonlinear analysis of structural and geological systems by the finite element method. The guide describes the capabilities and general features of the program and shows how input is prepared. A number of recent advances in finite element theory and computer technology are incorporated in the program. Nonlinear material properties are provided for, including isotropic, anisotropic, and time-dependent material properties, gravity loading, simulation of a sequence of excavation or construction, and a slip or joint element. The finite elements include beam, rod, axisymmetric and plane quadrilateral, hexahedron, thick shell, and axisymmetric and plane joint. The program also has an automatic mesh generator to minimize user input preparation for continuum finite element meshes.

Jan 1, 1976

By Christopher Mark

This proceedings volume contains papers presented at technology transfer seminars sponsored by the National Institute for Occupational Safety and Health (NIOSH) on New Technology for Ground Control in Retreat Mining. The seminars were conducted at five locations: Uniontown, PA (March 26, 1997), Norton, VA (April 8, 1997), Pikeville, KY (April 10, 1997), Charleston, WV (April 17, 1997), and Evansville, IN (April 22, 1997). The papers presented here describe several new, highly practical technologies developed by the NIOSH Pittsburgh and Spokane Research Centers3 to improve safety during pillar retreat operations. Two central issues are addressed: pillar design and mobile roof supports (MRS's). Proper pillar sizing is essential for safe pillar extraction. The Analysis of Retreat Mining Pillar Stability (ARMPS) program and its large data base of actual mining case histories are presented. LAMODEL, a second computer program, can be used for analysis of multiple-seam and other complex mining situations. Other papers address pillar design to avoid massive pillar collapses and the proper role of coal strength testing. MRS's have greatly improved safety where they are used for pillar line support. We studied the application of MRS's at 20 mines throughout the Eastern United States. Conclusions regarding the most effective section layouts, cut sequences, and support placements are reported. Field and laboratory tests of MRS's are also described.

Jan 1, 1997

By V. R. Spironello

The Bureau of Mines is involved in research directed toward the utilization of municipal solid waste. One of the primary objectives is the recycling of the magnetic fraction of municipal solid waste (raw refuse). This is consistent with one of the Bureau's goals, which is to minimize the requirements for mineral commodities by maximizing metals recovery from secondary domestic resources, In this investigation, cupola trials were made using combinations of refuse scrap with shredded automobile scrap under basic and acid slag practices. Furnace operating information and the behavior of alloying and tramp elements was obtained. The research showed that it is possible to utilize up to 60 percent refuse scrap in the cupola under basic practice and 30 percent under acid practice, Aluminum in refuse scrap, present in bimetallic cans, increased the recoveries of silicon and manganese charged to the cupola. Increased use of refuse scrap provided iron of lower sulfur. The alumina resulting from oxidation increased the slag volume. The aluminum and tin contents of the iron increased with increasing levels of refuse scrap in the charge. Lead was not a problem with respect to contamination of the iron. In basic practice, operation of the cupola was satisfactory since all slags were adequately fluid. In acid practice, operation became troublesome above the 45-percent level. Under both practices, the cupola iron melting rate decreased. Particulates in scrubber water and stack condensate samples contained lead, zinc, and tin, and the dust load increased. The tensile and transverse strengths of the iron produced under both practices are reported.

Jan 1, 1980

By Forrest T. Moyer

To keep the mineral and allied industries informed of trends in the causes of accidents and to point out the need for corrective measures, the Bureau of Mines collects, analyzes, and publishes, periodically health and safety statistics. This report includes data for 1961 on injury experience, with related employment statistics, at coal mines in the United Status. These data are presented in tabular form under the following headings; General Injury Experience Tables 1 to 6: Current data on number of injuries, degree of injury, frequency and severity rates, average severity, and related employment and production data by work location.

Jan 1, 1963

By H. N. Dunning

A comprehensive research program designed to aid development of new and improved methods for more complete production of petroleum from partly depleted reservoirs is being conducted at the Bureau of Mines Petroleum Experiment Station, Bartlesville, Okla. Water flooding has accounted for much of the petroleum produced by secondary-recovery methods; however, a considerable portion of the crude oil commonly remains in place after water flooding has been terminated. In recent years the possibility of increasing the efficiency of water flooding by using surface-active additives has received wide attention. In general, the results of laboratory research have shown that use of detergents as water-flooding additives will reduce the residual petroleum in porous media (1).3/ Some less extensive field tests have supported this conclusion but have not been entirely conclusive (2). Later studies (3, 4) have given conflicting evidence as to the relative worth of detergent additives for water floods in water-wet (hydrophilic) or oil-wet (hydrophobic or lipophilic) reservoir materials. The results of these studies emphasize the need for a more complete understanding of the fundamental principles involved in displacing petroleum from reservoir surfaces by injected fluids. Accordingly, a comprehensive research program was initiated to investigate the practical and fundamental aspects of detergency in petroleum production.

Jan 1, 1953

By Michael K. Phang

The use of explosives to fragment rock generates ground vibrations which may have a detrimental effect on contiguous underground coal mine openings. Increased surface blasting by a burgeoning number of surface coal mines and quarries has caused considerable concern among underground mine operators. Ground vibration effects generated from surface mine blasting are also causing public concern. In response to this concern, the U.S. Bureau of Mines (Stagg and Engler, 1980) has measured and analyzed ground vibrations and their effects on underground and surface structures. Some of the complaints registered against the mining industry are claims of substantial material damage from vibrations generated by the blasting; others are nuisance complaints of minor damage or annoyance. In general, allegations of damage from surface blasting have been sufficiently numerous to constitute a major problem for mine operators engaged in blasting operations. They have recognized the need for more technological data to evaluate the vibration problems associated with blasting. Both the operators and the general public need adequate safeguards based upon factual data to protect their specific interests. The coal mine industry needs reliable information from which to change blasting operations to reduce the number and severity of major damage claims and eliminate the growing number of nuisance complaints. The problem is of major concern not only to coal mine operators and nearby property owners, but also to federal, state and local governments. At the same time, environmental control agencies responsible for blasting and explosives use require reasonable and appropriate guidelines to protect the miners' lives.

Jan 1, 1984

By J. W. Thompson

A mining company for a period of 12 years bad been selling its ore to a certain smelting company for the purpose of obtaining a continuous and steady market for its ore and for the purpose on the part of the smelting company of obtaining a continuous and steady supply of ore for smelting; an agreement was entered into by which the mining company agreed to eell and the smelting company agreed to purcshase at ruling prices all the ore produced by the mining company of certain' stated grades, and to this end the mining company agreed to actively operate its mines. It is no longer the rule that a suit will not lie for the specific performance of a contract relating to personal property ; but the question for determination in such a case is whether the complainant has a plain, speedy and adequate and complete remedy at law, and if he has no such remedy, specific performance will be granted. In an action by a smelting company for the specific performance of a contract of sale it appeared that the ore produced by the mining company bad a peculiar value for smelt. i.ng purposes and was not readily obtainable elsewhere, and it would be practically impossible to measure the value for determining the loss the complainant would sustain· if the smelting company were not ,able ,to obtain the ore under the contract. It is comparatively simple for a court of equity to enforce the agreement as it pertains to the normal product of the mine and there is no plausible reason why a court may not require a performance on the part of the mining company where the mining company obligated it:Belf to operate all its mines. There is no delicate or complex condition involved in the production or delivery of the ore 'or in obtaining_ the stipulated prices agreed upon, and there is nothing apparent that will necessitate supervisory· control in requiring performance on the part of the mining company. A decree for specific perfoi:m,ance would require no supervision by the court either for the operation of the mines or for ascertaining and fixing the prices the mining company is to receive for its ore.

Jan 1, 1919

By R. S. Dean

This is the fourth of a series; of annual report of the Metallurgical Division to be released in this form and cover the fiscal year July 1, 1937, to rune 30, 1938. This report is not merely a recitation or brief of the year's work; it contains technical information in usable form, although a some of this has appeared or will he issued in greater detail in separate reports. The table of contents that follows fists the principal investigations accomplished and those that are being continued. Other projects are being begun and contemplated for the next year.

Jan 1, 1938

By August J. Kwitowski

This Bureau of Mines report summarizes the development of a protective operator compartment for a new generation thin-seam mobile bridge carrier. The developed compartment is commercially available and is currently employed on approximately 15 bridge carriers used in the mining industry. The design of the compartment, which employed human factors engineering and small- and full-scale mockup models, is fully described. Details of the compartment's fabrication, evaluation, and demonstration in a commercial low-seam coal mine are also provided.

Jan 1, 1986

By S. H. Lorain

This paper briefly describes the principal known commercial and near commercial deposits of gold-bearing gravel end the principal placer mining operations of Idaho County, Idaho. It is one of a series of similar papers on western mining districts. The data used in writing this paper were gathered during the summer of 1937. Information concerning gold-bearing gravels was obtained from prospectors and operators, while operators supplied most of the data on mining operations. No attempt was made actually to test the gravels. The principal object of the examination was to indicate placer areas worthy of further investigation by prospective operators.

Jan 1, 1938