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By Samuel P. Polack

This report reviews investigations to determine the fire hazard in coal mining when using flammable petroleum hydraulic oils to actuate mining equipment and summarizes research by the Bureau of Mines and industry on fire-resistant hydraulic fluids. Tests were established to evaluate fire resistance and the necessary characteristics to assure adequate service when fire-resistant fluids are used to replace petroleum hydraulic oils. The research was conducted in the laboratory and field trials under actual operating conditions in underground mines. Bureau of Mines Schedule 30 became effective December 17, 1959; the first approval was granted on February 18, 1960, and the twelfth was granted on March 17, 1961. The approvals include nine ready-mixed (by the producer) fluids and seven concentrates to which water is added by the user according to instructions from the producer. Seven synthetic-type fire-resistant hydraulic fluids submitted by two producers are also approved. Over 100 coal mines are now using water-in-oil emulsion-type fire-resistant hydraulic fluids in varying degrees from a trial in one machine to all the hydraulic equipment in an entire mine.

Jan 1, 1961

A computer system for calculating the illumination on coal mine surfaces due to machine-mounted lights is described. Utilizing numerical models of mining machinery and measured data on luminaire output characteristics, the program computes the ft-candle levels incident on the mine entry surfaces for any desired machine/luminaire/ entry configuration. Shadowing effects of the machine are taken into account. Results are provided at 2 ft. intervals on the face, left and right walls, floor and roof. The system operates, interactively from a Tektronix 4014 graphics terminal which handles all input/output functions. The software is installed on a Cyber 74 computer that communicates with the terminal via telephone line.

Jan 1, 1978

By E. D. Gardner

"Trolley lines used in connection with electric haulage in mines are a source of danger and many lives have been lost by men accidentally coming in contact with the wires. Usually the wires in metal mines are sufficiently guarded to prevent men from touching them with their person or by pieces of steel which they may be carrying or their shoulders, while walking along the level. However, it is difficult to guard effectively the wires at loading chutes along the haulage ways and in spite of safe guards, chute tappers have been electrocuted through loading bars accidentally touching the trolley line.To overcome this danger the Calumet & Arizona Mining Co., at Lowell, Arizona formely used a hinged V-shaped trough made of 1-inch by 6-inch lumber, that was dropped over the wire in front of the chute, when the cars were being loaded. This arrangement interfered with the easy operation of the chute, and a cut-out device for the trolley line was devised by W. R. Gibson, chief electrician for the company. This cut-out is efficient easily constructed and roes not interfere with the operations at the chutes or with the motors operating on the same level.When the cut-out is open the electric current is carried past the gap by an insulated wire on the opposite side of the drift. A hinged board drops down over the ends of the trolley guard when the slide is open and Prevents anything touching the live wires. About ninety of these cut-outs are now in use in the mine,The levels under the scopes are timbered with drift sets placed 5 feet apart, and the loading chutes take up the space between two sets. All trolley wires in. the company's mines are carried 6 feet above the rails and guarded by two 1/2 by 6-inch boards placed on either side of the wire."

May 1, 1921

By R. J. Hundhausen

The Shamrock copper-nickel mine in Jackson County, Oreg., was formerly a part of the Chisholm mercury property. In 1948 new owners advanced the old workings 40 feet to reveal encouraging widths of copper-nickel sulfide, ore on the Shamrock claim. When the owner's funds became exhausted, the Bureau of Mines carried on the development in 1949-50, completing 1,650 feet of bulldozing trenching, 396 feet of drifting, and 3,419 feet of diamond drilling. The Bureau's trenching disclosed a separate surface deposit 600 feet south of the mine deposit. This and the previously known deposit subsequently were diamond-drilled. The underground deposit has a known length of 100 feet, a dip length of. 100 feet and a width varying from 1 to 25 feet. The surface deposit is 200 feet long, 200 feet deep, and 5 to 38 feet wide. Neither deposit has been entirely delimited by development to date.

Jan 1, 1952

To reduce the respirable dust generated by auger-type continuous coal mining machines. The Approach: Use water sprays close to the cutting bits on the auger so that coal fragments are thoroughly wetted as they are formed to prevent dust dispersal into the ventilating air. How It Works: The "wet auger" system of dust control uses water sprays distributed on both shafts of auger type continuous miners. This approach has been tested underground by personnel of the Bureau's Twin Cities (Minn.) Mining Research Center on a Wilcox Mark 20 continuous miner, in a cost sharing contract with Buchanan & Sons Coal Company, Inc. Personnel of the Interior Department's Mining Enforcement and Safety Administration collected dust samples and analyzed the data. A test machine was fitted with six sprays on each auger (see Fig. 1). Water flow rates from 8 to 12 gpm at pressures from 90 to 120 psi, or about 8 gallons per ton of coal mined, were required. At these rates of water usage, mining personnel experienced no problems with work-

Jan 1, 1974

By Frank T. Duda

A U.S. Bureau of Mines interactive FORTRAN computer program can screen explosion-proof enclosures intended for underground service. The program incorporates important information and criteria to assist enclosure manufacturers and Mine Safety and Health Administration (MSHA) personnel by providing a first-order approximation of rectangular explosion-proof enclosure characteristics prior to actual certification testing. The program uses information and data that can be retrieved automatically during program execution. The program also performs the calculations for a series solution algorithm and various equations to evaluate the enclosure for both a static internal pressure and an internal explosion. The program writes the intermediate and final calculations and information concerning the status of the screening process to a summary file on a floppy disk. One data base contains MSHA certification requirements given in the Code of Federal Regulations (30 CFR 18). A second data base contains material properties of acceptable construction materials and weld joint efficiencies. A series algorithm determines bolt and cover stresses for a simply supported rectangular cover with arbitrary bolt locations. Limit and yield line analysis is used to calculate the strength of body panels.

Jan 1, 1989

By Robert F. Chaiken

An absorption-desorption model of particle reactivity was employed to describe the observed relationship between two apparently diverse phenomena which have been the subject of considerable study at the U.S. Bureau of Mines: (1) coal-rock dust reflectance and (2) coal-rock dust explosibility. The model accounts for heterogeneities in particle-size and material properties; however, in the present report, only particle-size distribution is considered. A mean particle-size parameter, appropriate to the explosion extinction process, is derived, and then taken as appropriate to describing optical reflectance. The derived form-to-function relationships for the two processes, when compared with experimental data, suggest that a problem exists with previously derived theory relating optical reflectance to rock dust concentration. A reexamination of that theory leads to a new theoretical expression, changed by a factor of 2, for the variation of rock dust concentration with reflectance which is in quite good agreement with experimental results. The current work offers justification for measuring and establishing rock dust requirements for specific coal dust size distribution(s) found in the mine-distributions that undoubtedly depend on the mining method and the type of coalbed.

Jan 1, 2010

By Lathrop E. Roberts

The opinion is general among smelter operators that magnetite formed in the converter and reverberatory furnace has much to do with the loss of copper in the slag. Its action appears to be due in part to its relatively high infusibility, chemical stability, and specific gravity, as a result of Which it tends to form a layer of highly viscous "magnetite mush" between slag and matte. Particles of matte which might otherwise settle out of the slag are unable to pass through this layer. Maier and Van Arsdele have shown that the inclusion of grills of matte in the slag is also at tires very probably due to chemical reaction between magnetite and the constituents of the matte. In smelter control and in any laboratory study of slats the determination of magnetite is therefore a matter of some importance. The difficulties in the ray of making such a determination with any accuracy are rather obvious. Iron may occur in slag as ferric oxide, magnetite, various intermediate oxides, sulphides, silicates, as free metal, and in solid solution of several of these substances. Even if only the total iron content is to be determined, accuracy can be obtained only by painstaking and time-consuming separations from interfering elements. The determination of ferrous, ferric, and free iron in the presence of each other is a difficult matter under the most favorable conditions, and when present in a slag the difficulties are increased by the refractory nature of the sample, by the presence of sulphides, and by such elements as vanadium and molybdenum.

Jan 1, 1931

By Lathrop E. Roberts

[The opinion is general among smelter operators that magnetite formed in the converter and reverberatory furnace has much to do with the loss of copper in the slag. Its action appears to be due in part to its relatively high infusibility, chemical stability, and specific gravity, as a result of which it tends to fern a layer of highly viscous. "magnetite mush" between slag and matte. Particles of matte which might otherwise settle out of the slag are unable to pass through this layer. Maier and, Van Arsdale4 have shorn that the inclusion of prills of matte in the slag is also at times very probably due to chemical reaction between magnetite and the constituents of the matte. In smelter control and in envy laboratory study of slats the determination of magnetite is therefore a matter of some importance. The difficulties in the ray of making such a determination with any accuracy are rather obvious. Iron may occur in slog as ferric oxide, magnetite, various intermediate oxides, sulphides, silicates, as free metal, and in solid solution of several of these substances. Even of only the total iron content is to be determined, accuracy can be obtained only by painstaking and time-consuming separation ions from interfering elements. The determination of ferrous, ferric, and free iron in the presence of each other is a difficult matter under the most favorable conditions, and linen present in a slag the difficulties are increased by the refractory nature of the sample, by the presence of sulphides, and by ouch elements as vanadium and molybdenum.]

Jan 1, 1931

By Robert A. Westin

Polychlorinated Biphenyls (PCBs) have been widely used as fire resistant dielectri coolants in electrical equipment used in mining applications, including transformers capacitors, electric motors, and electromagnets. In addition, PCBs have been used in hydraulic fluids and heat transfer fluids, and are present in many oil filled transformers. The Environmental Protection Agency recently banned the manufacture of PCBs and equipment using PCBs, and imposed strict requirements on the continued use and disposal of existing PCB equipment. This manual discusses the EPA requirements, suggest ways to decrease the risks resulting from continued use of PCB equipment, and surveys the non-PCB equipment that is available as replacements for the PCB electrical equipment presently used in mines.

Jan 1, 1979

By Fred N. Kissell

In This Chapter [Measuring the gas emission from the coal Methane at the top of the silo Methane at the load-out area and Actions taken after a silo explosion] Methane accumulations in coal silos have resulted in the occasional silo explosion. These can be quite violent and dangerous because coal dust adds to the strength of the blast. However, with the appropriate precautionary measures, methane accumulations in silos can be greatly reduced. Mine Safety and Health Administration (MSHA) regulations at 30 CFR2 77.201 require that the methane content in the air of any coal silo be maintained below 1.0 vol %.3 Also, MSHA requires that methane tests be conducted before any electrical equipment is energized, unless a continuous monitor capable of deenergizing the electrical equipment is used.4 Measuring the gas emission from the coal. The first necessary step in dealing with silo methane issues is to measure the gas emission from the coal going into the silo. Such measure-ments allow one to estimate the silo ventilation needs and permit a comparison with the methane controls used at other mines that have similar gas levels. The gassiness of the coal can be measured by taking conveyor belt grab samples.5 Matta et al. [1978] measured the gas emission from conveyor belt grab samples using a simple desorption test. To conduct the test, they collected several grab samples of coal, weighing a few pounds each, from the conveyor belt entering the silo.6 They then sealed the coal into an airtight sample container that was equipped with a valve and short hose along with a pressure gauge. Every few hours they opened the valve and bled the emitted gas into a water-filled graduated cylinder that had been inverted and placed in a pan of water (Figure 11–1). The results are shown in Figure 11–2.

Jan 6, 2006

The Thermo-MIE personal DataRAM dust monitor (pDR) is a light-scattering instrument approved for use in gassy underground mines by the U.S. Mine Safety and Health Administration (MSHA). However, the use of light-scattering monitors has been inhibited by concerns about inaccurate readings resulting from changes in dust size distribution and composition, as well as concerns about the impact of moisture in the mine air. Because of this concern, the National Institute for Occupational Safety and Health (NIOSH) evaluated the pDR using available data from laboratory tests and mine surveys. The data show that accuracy can vary widely from test to test and mine to mine. In most cases, the results can be improved by using a companion gravimetric measurement to adjust the pDR data.

Jan 1, 2006

By James E. Bell, Clyde B. White

"INTRODUCTION The Friedensville district was one of the most important zinc-producing areas in the United States from 1859 to 1893. The ore minerals near the surface were principally calamine and smithsonite, but with depth sphalerite was found in increasing proportions. The ore bodies of the district are reported to have been in chimneys, occurring in folded and faulted beds of Beekmantown limestone of Ordovician age.The Correll was one of five mines near Friedensyille that were exten¬sively exploited. The high-grade ore shoots were mined to a depth of several hundred feet, but it is believed that inability to compete with lower-cost production elsewhere, rather than exhaustion of the ore bodies, compelled the mines to close.There is no record to indicate that any attempt was made during the period of operation to explore for additional ore in the limestone beds down the dip below the mine workings. The possibility that exploration might reveal additional ore in the limestone beds below the known ore shoots led the Bureau of Mines to diamond-drill the Correll property between September 1943 and January 1944."

Jan 1, 1948

By Clarence A. Wright, JAMES T. NORTON, JAMES G. PARMELEE

The object of this paper is to give to mining companies and to all others who are interested some idea of the possibilities in the treatment, by differential flotation, of lead-zinc ores of the Coeur d'Alene region and other districts. The purpose of these investiga.. tions is not to evolve a differential flotation process that would replace present methods of gravity concentration but rather one that could be applied to the relatively fine material and slime produced in the mills and treated unsuc_pessfully by gravity methods or by flotation. It is expected, of course, that the products to be obtained by differential flotation would be of much better grade than those now produced by flotation in the Coeur d'Alene mills. In view of the fact that it has been difficult to obtain representative samples of flotation feed from the mills, owing to the necessity of shipping the material wet and free from oil or other foreign matter that might be deleterious to the differential separation of the sulphides, the writers have felt justified in running flotation tests with the mill feeds in order to ascertain whether a differential separation of the sulphides could be effected. However, two different lots of flotation feed were tested for differential flotation, and the results of tests of one of these are given in this report. It is hoped that it will be possible later to test out the flotation feed for differential flotation on a large scale in some of the mills. This paper covers part of the investigations carried on by the United States Bureau of Mines in cooperation with the Idaho Bureau of Mines, the University of Idaho, and certain mining companies of the Coeur d'Alene region. Although the results of the tests included in this report are not to be considered final, they indicate possibilities and may suggest others leading to a solution of the problem of separating lead and zinc sulphides by differential flotation in the treatment of certain ores.

Jan 1, 1921

By McHenry Mosier

Mechanical loading, adopted long ago in open-pit, coal, and non-metal mines, was not used extensively in underground metal mines until the World War. In less than a decade it became standard practice in underground work in many mining districts. In 1924 the Missouri School of Mines and Metallurgy, in cooperation with the Federal Bureau of Mines, published a bulletin entitled "Mechanical Underground Loading in Metal Mines," which was prepared by Charles E. van Barneveld, mining engineer, Bureau of Mines.

Jan 1, 1940

By E. L. Fosse, W. S. Wright

"INTRODUCTION Preliminary and detailed exploratory examinations of iron and copper ores on Prince of Wales Island have been conducted by the Bureau of Mines from early in 1942 until the end of 1944. Among these investigations was that of the Jumbo magnetite deposit, which was visited by Stephen P. Holt, an engineer of the Bureau of Mines, during a preliminary examination of the Copper Mountain and Jumbo properties September 15 to 18, 1943, During the months of June, July, and August 1944, a more detailed examination, which consisted essentially of mapping and sampling, was made by the authors working in conjunction with George C. Kennedy of the Geological Survey, Geological, topographical, and dip-needle contour maps were made of the area, and 97 channel samples were cut.ACKNOWLEDGMENTIn its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes sam¬ples and performs beneficiation tests. Both these branches are under the supervision of Dr. R. S. Dean, assistant director.Special acknowledgment is made to R. D. Stewart, Territorial Commissioner of Mines and former general manager, and to Duncan Campbell, Ketchikan, Alaska, former mine superintendent of the Jumbo mine. Acknowledgment is also due to George C. Kennedy of the Federal Geological Survey for extending cooperative assistance in topographical mapping, dip-needle surveying, and geological study of the deposits. Further acknowledgment is made to C. Travis Anderson, chief, Rolla Division, Metallurgical Branch, and other members of that division for conducting beneficiation tests on Jumbo Basin ores."

Oct 1, 1946

By F. K. McIntosh, L. A. Dahmers

"INTRODUCTION North Carolina has been the leading producer of mica in the United States, accounting for roughly 50 percent of the Nation's output. The producing area is a belt some 100 miles in width lying in the Mountain and Piedmont sections in the western part of the State. Ashe, Watauga, Avery, Mitchell, Yancey, Buncombe, Haywood, Jackson, Macon, Transylvania, Rutherford, Cleveland, and Lincoln Counties supply the bulk of production, while small amounts have been produced in Gaston, Catawba, Burke, Wilkes, Yadkin, Stokes, and Person Counties.To assist the operators and expedite the production of mica during the recent emergency, the Bureau of Mines drilled four of the more promising mica properties in this State. The results of this exploratory program are recorded in this report.ACKNOWLEDGMENTSIn its program of investigation of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each project as soon as practicable after its conclusion. The Mining Division, L. B. Moon, chief, conducts preliminary examinations, does the actual investigative work, and prepares the final report. The Metallurgical Division, O. C. Ralston, chief, analyzes samples and makes beneficiation tests."

Apr 1, 1948

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 Max J. Spendlove

The Federal Bureau of Mines has been a leader in resource recovery research since it was founded in 1910. Until the early 19601s, most of the projects were concerned primarily with the task of extending and improving conventional technology oriented to secondary metals and minerals upgrading and processing for marketable products of highest value. By the mid-1960's with the passage of the Solid Waste Disposal Act of 1965, all resource recovery research programs were increased in scope and intensity as an effort to solve the growing number of environmental problems and the rapid depletion of domestic energy and mineral resources. Many new materials were investigated including urban refuse, manufacturing, industrial wastes, and stockyard wastes. The objective was to promote maximum recycling as the most practical answer to problems of waste disposal, pollution control, and the short supply of minerals and energy. The new research projects ranged from the conversion of animal manure and other organics to oil, to the recovery of precious and common metals from demolished aircraft and electronic scrap. This profile includes brief descriptions of many selected research projects that typify, the total spectrum of Bureau of Mines research in the important field of resource recovery.

Jan 1, 1977

By L. C. IlsLey

"The use of trailing cables on cutting machines, loading machines, and similar electrically operated apparatus is recognized as a necessary adjunct to the economical operation of such units. On the other hand, such cables because of their liability to failure from being run over by cars, locomotives, and other track-operated equipment offer one of the greatest hazards - indeed, probably the worst hazard - met with in the operation and maintenance of permissible equipment. Therefore, the Bureau of Mines is seeking ways of making the use of trailing cables less hazardous.Recently the bureau conducted an extensive investigation of both concentric and duplex rubber-sheathed trailing cables at the Pittsburgh Experiment Station. The results of this investigation were published in two reports.3 4In a larger part of portable motor operations in mines a double-conductor cable can be used. The investigation already mentioned indicated that it is feasible to construct a 2-conductor cable that will stand considerable abuse, such as being run over by loaded cars or light-weight locomotives without producing dangerous arcing in the cable either from grounds or short circuits. There are conditions where more than two conductors are necessary, and in such instances it will probably be necessary to use a cable less resistant to this kind of abuse.Schedule 2C, covering the tests of electric motored equipment, was approved February, 1930. This schedule provides for performance tests on trailing cables as follows;Trailing Cable Performance: The following performance test, optional with the manufacturer, is established for determining the suitability of trailing cables for use on permissible equipment. Trailing cables that pass this test will be especially recommended for this service.The cable will be placed across the two rails of a track and a 4-wheeled 7-ton car will be run over it 50 times. The speed of the car shall be approximately 3-1/2 miles per hour and potential shall be applied to the cable during tests. The cable will be shifted in position after each passage of the car thus giving 100 places over which two wheels have passed. To warrant special recommendation of the Bureau, a cable must neither become short-circuited nor grounded either to the rails or wheels in more than 10 per cent of the 100 places.The Bureau of Mines is prepared to conduct tests as outlined in the foregoing paragraphs to determine the suitability of trailing cables for use on permissible equipment. Application for such tests should be made to the Director, Bureau of Mines, Washington, D. C. Each application should be accompanied by a check for $25.00, made payable to the Treasurer of the United States, to cover the expense of conducting the test on a given size and make of cable."

Apr 1, 1930