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By James H. Cobbs

The purpose of this study is to investigate the application of boring equipment to the production of anthracite coal from steeply pitching beds. Both raise boring and augering equipment were considered. Previous studies (11) have indicated that boring equipment may have definite applications to the development of steeply pitching anthracite beds. This investigation was to carry forward previous work to determine the possible application of the two different types of equipment being considered. Previous conclusions have been substantiated by the results of this study.

Jan 1, 1975

By R. W. Stahl

Coal mining has been revolutionized by the continuous miner. This machine has replaced, or has combined into 1, 3 former operations: Cutting, blasting, and loading. During the 25-year period before this machine was introduced, advances had been made in transportation, but the actual "coal getting" remained virtually the same. As frequently occurs, the multiple-purpose continuous miner introduced a new hazard--more rapid liberation of methane. The coal output formerly obtained from 10 to 20 working places might now be obtained from 1. It is true that circulation of air was generally increased; but the bulk of this machine virtually precludes continuous flow of air across the face, where gas may accumulate. Apprehension about this possible hazard led the Bureau of Mines to test face atmospheres during operation; and Report of Investigations 5288, Methane Buildup During Cutting and Continuous Mining Operations (published in 1956), presents proof that real danger may be present in many otherwise well ventilated mines.

Jan 1, 1958

By T. L. Marchewka

As part of its program to conserve the Nation's natural resources by developing improved performance materials, the Bureau of Mines, U.S. Department of the Interior, in cooperation with the U.S. Department of Energy, has conducted an investigation of materials of construction able to withstand the high temperature and hostile environments encountered in coal gasification units. Refractory pipe liners are required when extremely hot gases or abrasive solids are transported between processing units in the gasification plants. One promising technique for producing refractory pipe (or refractory pipe liners) is centrifugal casting. For this study, the effect of processing variables such as workability, additives, reinforcement and spinning time, and centrifugal force were evaluated using four commercial refractory concretes. In addition, data on characteristics such as strength, density, abrasion, and spalling resistance of 5-inch-diam refractory pipe were developed. Techniques for forming large-diameter (19-inch) refractory pipe also were evaluated. The test results indicated that all four refractory concretes could be made into strong, homogeneous pipe, but that optimum casting parameters had to be determined for each specific composition. The investigation revealed that the major controlling factor in the production of the centrifugally cast pipe was the workability of the refractory concrete.

Jan 1, 1979

By Anthony W. Sparks

The Bureau of Mines conducted tests designed to compare its breathing metabolic simulator (BMS) with other methods that are currently used to evaluate the performance of respiratory protective equipment. The BMS is a commercially developed device that uses a piston cylinder to simulate breath movement. Using a propane furnace that consumes oxygen and forms CO2, the BMS also simulates the respiratory metabolism of humans. The breathing and metabolic subsystems of the BMS are described in detail in this report. Results are compared from tests that used the BMS to evaluate respiratory equipment and from tests that used human subjects for the same purpose. The BMS was also tested against a pulsatile breathing machine (PBM) previously designed by the Bureau. Both machines were used to test respiratory equipment, and the test results are compared in this report. To illustrate typical applications of the BMS, the report briefly describes how the BMS was used to test two different types of closed-circuit respiratory apparatus, and the test results are presented. This research showed that BMS test results compared more closely to the results of tests that used human subjects than did results obtained using the PBM.

Jan 1, 1980

By Clyde E. Williams

The Northwest experiment station of the Federal Bureau of Mines , at Seattle , Wash . , was established in December , 1916 , and is one of 13 mining experiment stations maintained by Act of Congress , under the direction of the bureau , in the various sections of the country . Under the terms of the organic Act (March 3 , 1915 ) , the province and duty of these experiment stations is to cake investigations and disseminate information with a view to decreasing waste and improving the efficiency in the production , treatment , and utilization of mineral substances . The investigations carried on at the Northwest experiment station attempt to cover the needs of the mineral industry of the States of the Pacific Northwest and of the coastal regions of Alaska . The most in ortant needs of this district are for work on coal washing , electrometallurgy , and ceramics . The electrometallurgical investigations are not necessarily limited to the Problems of the Northwest , but may be of general application . Problems other than those specified above are referred to other stations of the Bureau that specialize on the particular type of investigation required . The Northwest station closely cooperates with the State of Washington through the University of Washington and with the State of Oregon through the Oregon Bureau of Mines and Geology . The University of Washington at Seattle has donated the use of an entire building , which houses the station's administrative offices and chemical laboratory , and parts of two other buildings which are usea in conducting the experimental avestigations . Twenty-five thousand dollars is expended annually by the Federal Government , while the State of Washington each biennium appropriates $ 20,000 , and the State of Oregon from time to time appropriates various amounts for the conduct of work along cooperative lines . Also , the station cooperates with private organizations tht have problems similar to those in which the station is interested . For example , the Washington Electrochemical Co. is cooperating in the electrometallurgical research, and furnishes part of the supplies and technical assistance required .

Mar 1, 1922

By S. P. Sandoval

Several researchers have shown that the surface of chalcopyrite becomes hydrophobic under oxidizing conditions. Because dissolution of copper from chalcopyrite in dump leaching occurs under oxidizing conditions, the U.S. Bureau of Mines studied the effect of surfactants on chalcopyrite leaching under dump chemical conditions. Surfactants were selected for study because they can lower interfacial tension. The tests were conducted in shaking water baths using 250-mL Erlenmeyer flasks in statistical experimental design formats. The addition of nonionic surfactants increased copper extraction in the fernc sulfate leaching of chalcopyrite when sufficient Fe3+ was present. A positive interaction between Fe3l+ concentration and surfactant concentration was demonstrated. Copper concentration in the leachhing solutions was increased by as much as 100 pct at 25° and 50° C by adding nonionic surfactants. ionic surfactants decreased leaching. The structure of the nonionic surfactants and their hydrophile-lipophile balance (HLB) influenced surfactant performance. The branched hydrophile of an ethoxypolyol was beneficial to surfactant performance. The ethoxypolyol was the superior surfactant at 25° C, but became unstable at 50° C. Four surfactants, an ethoxyalchohol and three block copolymers, performed best at 50° C.

Jan 1, 1990

By Sidney A. Suhler

A field operable, breadboard model, borehole radar was developed for the detection of hazardous geological anomalies in and above a coal seam in advance of mining. A four-inch diameter downhole probe was fabricated and tested in several environments. The radar transmitter was also employed in a cross-hole or through transmission mode to determine natural geotechnical and man-made conditions between boreholes. Sensitivity to underground conditions in both modes of operation were indicated.

Jan 1, 1978

By George H. Holmes

This paper , which describes mining methods and milling and manufacturing operations at the gypsum property of the Blue Diamond Corp. , is one of a series on mining methods and practices being prepared by the Mining Division of the Bureau of Mines . The property comprises about 4,000 acres and is in secs . 30 , 31 , 32 , and 33 , T. 21 S. , R. 59 E. , and secs . 5 , 6, 7 , 8 , and 9 , T. 22 S. , R. 59 E. , M. D. B. and M. , Clark County , Nev . , approximately 23 miles by paved highway southwest of Las Vegas , Nev . ( fig . 1 ) . This circular summarizes the history of company operations , describes physical features , labor and living conditions , and the geology . The method of exploration is outlined , and the section on mining methods contains descriptions of open - pit and underground systems , including loading and transportation methods . The crushing plant and tramway are described , as well as plaster-mill and board -plant practices . The boiler plant and organization are described , and wage scales are contained in the concluding section of the circular .

Mar 1, 1950

By Oliver Bowles

It is noteworthy that 80 to 95 per cent of the gross production of all slate quarries in the United States is discarded as waste . In view of the loss involved in handling so much waste , and the consequent added cost of the finished product , the Bureau of Mines has undertaken a study of the slate industry for the purpose of devising the best means of reducing the proportion of waste , and of utilizing the unavoidable waste . The utilization of waste has received special attention , and the cooperation of many prospective purchasers of waste slate has been enlisted in testing its adaptability for various uses .

Mar 1, 1921

By S. H. Katz, J. J. Bloomfield

Fires in zinc dust have sometimes given particular trouble owing to their resistance to extinguishers and the liability of explosions . Similar problems , notably with aluminum dust* , have previously been subjects of investigation by the Bureau of Mines .

Mar 1, 1922

By Harold L. Riley

This Bureau of Mines paper describes the methods and practices used at the Peck quarry of the Crab Orchard Stone Co., Inc., one of the leading producers of dimension stone in the Crossville, Tenn., area. The product is marketed under the registered trademark "Crab Orchard Stone". Another large producer of stone from the Crossville district sells its product under the registered trademark of "Tenn-Quartz". Both companies, and a number of other companies and individuals who quarry and process dimension stone from the same general geological formation, are members of the Quartzite Producers Association of Tennessee. The salable product is shipped throughout the country for use as architectural building stone. In 1959, 653,008 cubic feet of stone was produced in the Crossville area and was sold for $1,414,405. Terms and descriptions used in this report are those of the quarry and building trades. The offices, pitching sheds, wire saws, railroad siding, and storage areas of the Crab Orchard Stone Co., Inc., are on a side road 0.3 mile north from a point 2.2 miles east of Crossville, Tenn., on U.S. Highway 70. The quarry is on this same side road 2.0 miles south of Highway 70. Crossville is 62 miles west of Knoxville and 65 miles northeast of Chattanooga, Tenn.

Jan 1, 1962

1. In 2002, a total of 4,311 stone mining operations reported employment to the Mine Safety and Health Administration (MSHA). The major industrial classifications in stone mining are dimension stone (used for construction purposes), crushed and broken stone (aggregates), cement, and lime. Stone mines comprised 29.7% of all mining operations. • Mines producing crushed and broken stone (n = 3,372) comprised 78.2% of all stone mining operations.

Jan 1, 2004

1. In 2003, a total of 258 metal mining operations reported employment to the Mine Safety and Health Administration (MSHA). Metal mines were the smallest mining sector, comprising 1.8% of all mining operations.1 • Gold mines comprised 44.2% (n = 114) of all metal mining operations. Other common types of metal mines were iron ore (n = 29; 11.2%), copper ore (n = 28; 10.9%), and lead and/or zinc ore (n = 21; 8.1%). • Nevada had the largest number of metal mines (n = 48; 18.6%) followed by Alaska (n = 29; 11.2%).

Feb 1, 2005

By P. E. Churchward

Rhenium sources and recovery methods were investigated by the Bureau of Mines to delineate potential resources of the metal. The only significant rhenium resource appears to be about 28,000 lb of rhenium contained in the domestic annual output of approximately 20,000 tons of byproduct molybdenite concentrates from porphyry copper operations. An estimated 70 to 80 pct of this rhenium is potentially recoverable by processing the rhenium-bearing fumes and dusts obtained during conventional roasting of molybdenite concentrate. At 70 pct recovery this would amount to 19,600 lb of rhenium. A more conservative estimate by the Committee on Refractory Metals of the National Research Council (1513 is that 12,000 lb of rhenium metal could be produced annually from current production of molybdenite from porphyry copper operations in the United States. A procedure was developed in the laboratory for recovering rhenium in the form of electrolytic flake by electrowinning the metal from a solvent extraction strip solution. The procedure included (1) water leaching of molybdenite roaster flue dust, (2) selective extraction of rhenium from the leach liquor by contacting it with a kerosine solution of a quaternary amine, (3) stripping of rhenium from the loaded organic solution by a perchloric acid solution, and (4) electrodeposition of rhenium from the loaded strip liquor. Raw material for the studies was flue dust containing 0.48 pct Re, 35 pct Mo, and 23 pct S in sulfide and sulfate form, and small amounts of numerous metallic impurities. Water leaching dissolved 85 pct of the Re and yielded a solution that was 13 in sulfuric acid and contained, 1 g/l Re and 16 g/l Mo. The solvent extraction strip solution that was electrolyzed for rhenium deposition was 1 molar in perchloric acid and 1 molar in ammonium sulfate and contained 13 g/l Re and 0.01 g/l Mo.

Jan 1, 1963

The Bureau of Mines conducted a field study to assess the performance of various chain pillar configurations in terms of gate road entry sta-bility. Vibrating wire stressmeters (VWS's) were installed in four consecutive gate road chain pillars. Field data collected during panel retreat were analyzed to gain a better understanding of the mechanics of vertical load redistribution in gate road chain pillars as it relates to ground control problems. Several different pillar configurations were investigated including abutment-yield and yield-abutment-yield designs. VWS data indicate that average pillar loads were lower and appeared abutment-yield pillar arrangement was utilized. port the occurrence of severe roof and pillar to stabilize when an Data analyses also supdeterioration that was visually observed in the tailgate entries during panel extraction.

Jan 1, 1988

By E. D. Gardner

A custom gold and silver plant is one that treats ores for a fee. Usually such plants are located in mining districts and treat local ores. Ores of milling grade generally can stand only moderate transportation charges. These plants are scattered throughout the West. Most plants now doing a custom business originally were built by mining companies to handle ores from their own mires. As excess mill capacity became available ores from neighboring properties were treated, vainly as an accommodation. Later, as their own ore bodies became depleted, the mills were operated entirely on a custom basis. A few plants pull ore from their own mines only when the supply of custom ore is insufficient to keep the mill operating. Some of the present custom plants were built for custom work alone. Although built originally to treat the ores of the Golden Cycle mine, the Golden Cycle plant at Colorado Springs, Colo., soon became a custom mill and has been operating successfully for many years. It is the largest gold mill in the Western States and. treats Cripple Creek ores, from which most of its tonnage still comes. The plant is equipped to treat a great variety of ores and receives shipments from a wide area. It competes with smelters in Colorado, as it has a roasting plant to prepare sulphide concentrates for treatment in its cyanide plant. Most custom mills, however, are not adapted for more than one or two kinds of ore. Gold occurs in its ores both in the metallic state (free) and locked up in sulphides. It also occurs in a few places, notably at Cripple Creek and a few other Colorado districts, as tellurides. Mien the gold occurs in the native state, the ores is said to be free-milling and can be recovered by amalgamation. Usually, however, some subsidiary treatment is required to make a satisfactory extraction. Amalgamation generally was followed by tabling in the earlier mills; at present, flotation has replaced tables at many places. As depth is reached in raining and the workings extend below the oxidized zone the character of the ore usually changes, or, as the miners say, "it gets base". Since the advent of flotation, the average recovery of gold in base ores has been improved-greatly. Cyanidation is applied to some types of both gold and silver ores. The recovery by cyanidation is in general considerably higher than by other methods in vogue and in addition has the advantage of making a finished product which can be sold directly to the mist, thus obviating smelting charges on concentrate and discounts

Jan 1, 1935

By A. R. Elliott

"In addition to the usual interpretation that is placed on the words ""thief"" and ""thieves"", the petroleum industry also uses these words when referring to an instrument that is used for taking samples of oil from a tank or reservoir. It is an abbreviation of the term ""thief-tube"". It is desirable in sampling volumes of oil in tanks or reservoirs to obtain samples at different intervals below the surface of the fluid, because of the variation in the character of the oil at different depths. It is for this purpose that the ""thief"" is used.The subject of oil thieves is probably as old as the oil industry itself. Opinions as to which is the most practical instrument for thieving oil in tanks, to obtain a true average sample, differ wherever oil is produced and is analyzed. Every district, and even many of the companies within the district, will have different appliances for ""grabbing"" oil samples. It is interesting to note in passing that though the thief has an apparently insignificant part in the handling of oil, yet the results depending on it are of paramount importance practically every branch of the transportation, refining, and marketing of petroleum. Determinations, particularly dependent on a representative sample, are made by the centrifuge, laboratory distillation tests, and the hydrometer.The purpose of this article is to discuss conditions found in the California fields. Only a general description of types of thieves and the methods of using them will be given. However, it is believed sufficient data are given to enable the reader to form his own opinion as to which of the devices is most practicable under the prevailing conditions. Thieves of all types have their good points, speaking broadly, and it is possible to get good results with any of them, provided they are operated according to instructions and with due care. In work of this kind the advantages or disadvantages reside in the person operating the instrument rather than in the instrument used."

Apr 1, 1920

By M. L. Williams

In recent years the use of visual aids has expanded the? field of safety education. This is a modern adaptation of a method employed in ancient times, when simple paintings and drawings were the only means of recording current events. In its present application, visual aid employs sound and silent motion pictures, stripfilms, lantern slides, descriptive posters, and color. According to Roberts,3/ "Visual education is a method of imparting information which is based on the psychological principle that one has a better conception of the thing he sees than of the thing he reads about or hears discussed." Dent4/ further defines visual aid as "all the materials used to facilitate the understanding of' the written or spoken word."

Jan 1, 1951

By William C. Miller

This report describes investigations by the Bureau of Mines designed to establish the noise level and spectrum of various types of pneumatic rock drills and to furnish information that would be useful in conducting sound measurements in mining environments and in reducing the noise generated in pneumatic drilling. These investigations show that (1) the noise generated by the drills in the frequencies below 100 cps is caused by the impact of the piston and drill steel, in the frequency range between 100 and 2,000 cps by the exhausting of air from the ports, and in the frequencies above 2,000 cps by the resonant frequencies of steel drill parts and of drill steel; (2) satisfactory instruments and instrumentation systems are available for field and laboratory measurements; (3) reliable sound measurements can be made in mining environments; and (4) devices can be developed that will abate the noise.

Jan 1, 1963

By W. H. Forbes

The prevention of accidents from falls of roof and coal requires a considerable amount of personal judgment , for conditions are different even in adjoining working places in the same mine , and conditions may change from hour to hour even in the same working place as the coal is shot down and loaded . Experience has shown that many men can not or do not exercise enough care to protect themselves from injuries ; moreover , where the foremen have been made directly responsible for the safety of the men under them , accidents from falls of roof and coal have , in many instances , been reduced as much as 50 per cent . There is now no question that careful , constant , and intensive supervision is essential in preventing acci- { dents and more especially accidents of this class . Falls of roof and of coal account for approximately 50 per cent of all coal mine accidents and annually result in the death of approximately 1,000 men and cause lost - time injury to approximately 50,000 men . These and other accidents are recurring with little or no diminution , usually not because of the lack of knowledge of safe and dangerous practices , or of the technique of safety , but largely because of the lukewarm interest of major executives in safety or the failure of mine officials to formulate and to enforce common - sense rules and regulations . When failure is the outcome of a sincere attempt of the managing officials to teach safety to the miner , the fault may usually be attributed to misguided effort . Various solutions for the problem of eliminating accidents from falls of roof or coal have been suggested , some of which are : Standard system of timbering for the specified mining districts ; departure from the room-and - pillar system to a more concentrated system of mining ; more intensive supervision - that is , 1 section foreman for every 25 loaders instead of 1 section foreman for 75 , 80 , or even more loaders the practice in most mining districts . - However , investigations conducted by the writer at numerous mines operated by a number of mining companies in several districts show that employees and officials alike are inclined to work under loose and unsupported roof , relying solely on the " drummy " sound and on their judgment and experience as to whether the roof will stay in place for one hour or for several hours . With but few exceptions , men who had been injured by falls of roof or ccal or were found working under loose and unsupported roof , admitted that they knew of the possibly unsafe condition , but it was their opinion that the roof or coal was not loose enough to fall for some time .

May 1, 1931