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Improve the dust control effectiveness of dry collection systems on surface coal mine drills. Approach Use a dust pelletizer to convert the respirable dust particles discharged by the dry collector into dust pellets that present no health hazard. Background Blasthole drills are well-known sources of respirable dust that can contain significant amounts of quartz. The drills frequently use a dry cyclone-filter type collector that can obtain dust reductions theoretically greater than 95 pct. However, surface mine drills using dry collectors typically have three major dust sources that significantly reduce the overall effectiveness of the collection system: (1) the dust collector dump cycle, (2) drill shroud leakage, and (3) leakage around the drill stem seal in the drill table.

Jan 1, 1989

Develop a means for analyzing seismic crosshole data to predict and monitor the Flow of leach solution during in situ mining. Background Improvements in predicting and monitoring in situ leach solution flow would aid in planning well field configurations. These improvements would also facilitate permit application by assuring regulatory agencies that leach solution would not escape from a well field undetected. Seismic tomography can detect fractured zones, which enables the prediction of probable flow paths, and it is a promising technique for monitoring leach solution injected above the water table. Tomographic analysis of crosshole seismic data provides a two-dimensional picture of the distribution of seismic velocities between the transmitter and receiver boreholes. The positions of fractured zones and of leach solution can then be inferred from the seismic velocities.

Jan 1, 1989

Reduce the dust exposure to the operator of a longwall shearer with a novel foam spray system. Approach Discharge foam through the nozzles of a shearer drum so that foam and coal are better mixed. How It Works Bureau of Mines research showed that two very important principles for successful application of foam are: (1) moisture distribution and (2) degree of mixing. Foam can distribute a given quantity of moisture much more evenly over a large surface area. Successful Bureau tests of foam for dust control always involve a high degree of mixing between the foam and the material, Mixing, permits a greater distribution of foam throughout the mined product. The most suitable location of foam application would be at the point where the dust is generated, before the dust becomes airborne. Foam nozzles located in the cutter drum (pick face foaming or ejecting foam through scroll sprays) will suppress dust close to its source.

Jan 1, 1989

Develop an inexpensive, reliable means of quickly detecting and locating trapped miners in underground coal mines, particularly after a mine accident. The Limitations Although the Bureau of Mines has performed extensive research on the use of electromagnetics for locating trapped miners, much of its research trends toward the development of long-range systems designed to locate an underground transmitter from the surface. Such location systems are beneficial; however, there are several limitations regarding their use. Two limitations are weight and cost of the equipment. Most long-range detection systems would be too heavy and cumbersome to be accepted by miners as part of their daily protective equipment. Since such long-range detection systems are usually expensive, it would not be economically feasible for every miner to be provided with a system.

Jan 1, 1984

Reduce spillage hazards and contamination when adding hydraulic nil to mining machine reservoirs. Approach An easily transported module, that delivers hydraulic oil directly into mining machines, was built and tested. How It Works The Hydraulic Oil Delivery Module is carried, from the oil storage area to the equipment needing oil, in the bucket of a scoop or other utility vehicle. Oil is pumped into the module reservoir from storage, or out of the module reservoir into the machine being serviced, through a long hydraulic hose. During long-term testing, the 115 foot long delivery hose made it possible to replenish the hydraulic oil in mining machines at the face with only limited interruption to the mining operation. (Figure 1 shows one! version of the module.) The compact Hydraulic, Oil Delivery Module consists of: an oil reservoir: a pump driven by a hydraulic motor; two high pressure, low volume oil lines, filters; and a low pressure, larger capacity delivery hose equipped with quick-connect-couplers. The high pressure oil lines are connected to the scoop's hydraulic power takeoff, which supplies the power to pump oil in or out of the module reservoir.

Jan 1, 1977

Determine the effectiveness of remining operations in reducing contaminant load (acidity, iron, and sulfate) of discharges emanating from abandoned surface and underground coal mines. Background Until the implementation of remining initiatives, most States had regulations that held the operator remining an abandoned site responsible for preexisting acid mine drainage (AMD) discharges. For example, if a mining. company wanted to remine an area hydrologically connected to an existing AMD discharge, the company became responsible, as soon as the site was activated, for treating that discharge to meet effluent standards. If the mining operation improved the quality of the discharge, but the discharge failed to meet effluent standards, the company was held accountable for perpetual treatment. Because of this regulation, most mine operators avoided abandoned sites with minable coal reserves and AMD discharges. However, changes in remining legislation allow coal companies to be released from treatment liability as long as the post-remining pollution load does not exceed the pre-remining level. If remining can improve water quality through improved mining and abatement techniques, abandoned mine land (AML) areas that previously were liabilities could become

Jan 1, 1994

By D. J. Parker, D. Harrington, L. H. Harrison

The necessity for protection against the hazards of lightning manifests itself from time to time in the mining industry by reason of loss of life, damage to electrical equipment, fires in surface structures at mines, and accidents in the handling and use of explosives. This paper is intended to assemble, correlate, and present some of the salient. points embodied in the available literature on the subject and at the same time give some factual data concerning instances of such loss of, life and damage to property, with special application to the mining industry The annual loss of life and destruction of property by lightning is considerable; the former may be prevented to a limited extent, though use of common sense as to exposure is required and not always followed; the latter can be prevented to a considerable degree. The manufacturers of electrical equipment,, through improved types of lightning arresters,, have done much toward the protection of electrical equipment, with consequent safeguarding of life and of property. Education based on unfortunate experiences has gone far to discourage the handling of explosives and blasting accessories during thunder storms, especially in open pits and quarries, and to a much smaller extent in underground workings. The lowly lightning rod plays an important role in the protection of certain types of buildings (especially isolated buildings), stacks, monuments, and other structures. LIGHTNING PHENOMENA In 1751, Franklin proved that lightning was simply a visible display of electricity - an extended spark; and until a generation ago little had been added to his exposition, to define the various phases of the phenomenon. Matters pertaining to lightning are discussed in the following references:

By George R. Schottler

The Bureau of Mines investigated the distribution of uranium and various methods of ore sampling in a uranium deposit typical of those in the Morrison Formation sandstone of the Ambrosia Lake area, Grants mining district, north-western New Mexico. Chemical and radiometric assays of diamond-drill core samples are compared in detail by statistical techniques, and the assay data are correlated with the stratigraphy of the deposit. Conclusions applicable to ore-reserve estimation in geologically similar uranium deposits are drawn.

Jan 1, 1971

By James R. Welty

Heat content values were experimentally determined for yttrium metal between temperatures of 400° and 1,300° K and for iron pentacarbonyl between 301° and 380° K. The drop technique was used; that is, a sample of material sealed in a protective capsule was heated to 3 desired temperature in a furnace and then dropped into an ice calorimeter. A revised technique for determining heat content values from calorimetric data is described. Heat content and corresponding entropy-increment data above a reference temperature of 298.15° K are presented in tabular form. Equations for heat content and heat capacity as functions of temperature were derived for each substance. These equations are [Y (c): HT-H298.15 = 1.2041T 1 3.393 x 10-3T2- 0.4176 x 10' T"1 + 739.9 cal/mole Cp = 1.2041 + 6.786 x 10-3T + 0.4176 x 106-T-2 cal/deg mole Fe (CO) E, (1) : HT - H298.15 = 55.636T - 16,588 cal/mole Cp = 55.636 cal/deg mole]

Jan 1, 1963

By I. D. Shah

Thermal decomposition of copper (II) sulfate (CUS04) and copper (II) oxy-sulfate (CuO?CUS04) are important steps in the overall oxidative roasting of covellite (CuS) and chalcocite (Cu2S). Nonisothermal thermogravimetric techniques were used to investigate the decomposition reactions in flowing Na and air. Thermal decomposition of CUS04 and CuO?CUS04 followed "linear" kinetics with an apparent activation energy of 55±2 and 66±3 kcal per mole decomposed, respectively. These apparent activation energies comply with those previously reported when isothermal kinetic techniques were used. The addition of oxygen decreased the rate of decomposition, while small amounts of iron which were admixed with CuO?CUS04 did not have a significant effect. Neither oxygen nor iron had any appreciable effect on the apparent activation energy of the decomposition reaction.

Jan 1, 1972

By B. Dimitriades

Experimental work has been done to refine and to confirm an analytical procedure by which gas-liquid chromatographic (GLC) spectra are interpreted from retention time data alone. The rationale of this spectra interpretation technique involves whether or not a given peak invariably represents the same component or component mixture; if not, what factors influence changes in peak identifications. To answer these questions, peak-identification procedures, based mainly on the use of subtractive columns, were developed and applied to interpret GLC spectra of several exhaust (and fuel) samples.

Jan 1, 1972

Generate less respirable dust during mining by reducing the clogging and downtime of the water sprays on mining machines, especially on continuous miners. Approach An improved filtering system, having commercially available components, has been designed and tested. How It Works The improved filtering system shown opposite is mounted on the mining machine, where It traps particles of coal and pipe scale which cause most clogging of the water sprays. Water entering the system first flows through a ?Y" strainer, which screens out particles larger than 1/8 inch diameter. Next, the water whirls through a small hydrocyclone. Most of the remaining smaller particles are removed and pass Into the accumulator compartment built into the hydrocyclone. The water also flows through a final filter. This filter catches particles that might pass the hydrocyclone, especially during water spray start-up and shut-down, when the speed of the water flow is not sufficient for

Jan 1, 1976

By Rose L. Ballard

This chapter summarizes data on crude nonfuel mineral production for the United States, its island possessions, and the Commonwealth of Puerto Rico. Included also are tables that show the principal nonfuel mineral commodities exported from and imported into the United States, and that compare world and U.S. mineral production. The detailed data from which these tables were derived are contained in the individual commodity chapters of volume I and in the State chapters of volume II of this edition of the Minerals Yearbook. Although crude mineral production may be measured at any of several stages of extraction and processing, the stage of measurement used in this chapter is what is normally termed "mine output." It usually refers to minerals or ores in the form in which they are first extracted from the ground, but customarily includes the output from auxiliary processing at or near the mines.

Jan 1, 1982

By R. A. Guidotti

The Federal Bureau of Mines has studied the reaction of oxides of columbium, vanadium, and tantalum with ammonia in vertical, gas-solids reactors at temperatures ranging from 300° to 1,300° C with the goal of preparing nitride intermediates for subsequent preparation of the metals by a thermal-decomposition step. The best nitride conversions were obtained in nonmetal reactors. With Cb205, V2O3, and V205 , low-temperature maxima in reaction rates occurred at 800°,800°, and 450° C, respectively, during oxynitride formation (in A1203) at 1 atm of pure ammonia. Conversion of the oxynitride, in a second step, to the mononitride was optimum at 1,200° C for columbium and 1,050° C for vanadium. In the case of Ta205, the rate of reaction to form Ta3N5 (in a single step) was highest at 900° C, where the presence of up to 5 percent methane was found to be beneficial; improved results were obtained by conducting the nitriding in a rotary kiln. Optimum space velocities (in the vertical Al203 reactor) ranged from 5,280 hr-1 for Cba205 to 7,950 hr-1 for V203. Oxide particle size had little effect upon reaction rates. Under fully optimized conditions, products containing less than 1 percent oxygen were readily obtained in under 6 hours.

Jan 1, 1975

By Ann G. Kim

The Bureau of Mines investigated factors that influence the formation of methane and other hydrocarbon gases in coal, which is an integral part of the coalification process. Coalification begins with a biogenetic stage in which plant debris decomposes and peat is formed; methane and CO2 are the predominant gases produced during this stage. During the diagenetic stage of coalification hydrogen and the hydrocarbon gases methane, ethane, ethylene, propane, propylene, butene, iso-and normal butane, and pentane are formed by dissociation of the organic material. Methane may also be produced by a secondary reaction of hydrogen with unsaturates or by the reduction of CO2. The gas contained in coalbeds is a mixture of methane, C2 through C5 alkanes, CO2, O2, N2, H2, and He; its heating value is equivalent to that of natural gas. The gas content of coal depends on many variables, but an empirical relationship between adsorptive capacity, rank, and depth has been observed.

Jan 1, 1978

By Barbara J. Halpern

There?s no denying that mining is a male-dominated industry. Yet thanks to technologies developed over the last 20 years, societal changes in sex role stereotyping, individual determi­nation, and the willingness of companies to train women, there are no jobs in mining today where women are not represented. Women are drillers and electricians as well as drivers of heavy equipment and haulpack trucks. They perform jobs ranging from field exploration and metallurgy to clerical and janitorial and warehousing positions, from prospectors and underground blasters to geologists and land reclamation experts, from communicators to legal experts on mining law and more. The Women?s Mining Coalition, founded in 1994 to shepherd responsible legislative mining reform, estimates that 20 percent of the workers in the mining industry are women. Although women are concentrated in clerical and adminis­trative jobs, at least 10 percent are in non-traditional, hardhat jobs, claims the group. There are women in management, but the numbers in senior management remain small, especially in larger companies.

Feb 1, 1998

By Philip A. Holland

The Bureau of Mines has developed a method for determining helium in water for use in sampling and analyzing surface and subsurface waters for geochemical survey work. The accuracy of the analytical method is within ±10 percent for samples containing above 20 x 10-8 cm3 He (STP)/cm3 H20. The minimum detectable helium-in-water concentration is calculated to be 2 x 10-8 cm3 He (STP)/cm3 water. Water samples are collected in 500-cm3 stainless steel cylinders. The dissolved gases are extracted into a cylinder of equal volume containing a known quantity of neon. The resulting gas mixture is subsequently analyzed for helium and neon-21 by mass spectrometry. The volume of helium in the sample is calculated from the mass spectrometric determination of the helium-to-neon-21 ratio, the known quantity of neon used, and the extraction efficiency of helium.

Jan 1, 1981

By R. V. Ramani, R. Stefanko, G. W. Luxbacher

TEST DECK – ALTMETER SURVEY WITHOUT PLTTMETER TEMPERATURE CCRRECTION DATA INPUT

Jan 1, 1977

Federal lands often contain extensive mineral resources and decisions affecting access to those lands are made with knowledge of the possible minerals-related consequences. Information is provided to the Bureau of Land Management (BLM) in this report for use in preparing environmental impact statements on the Western Mojave Management Area (WMMA) and the Desert Tortoise Priority Habitat (DTPH). To augment U.S. Bureau of Mines (USBM) efforts such as the Mineral Assessment of the Planned Foil Irwin Expansion, Modified Silurian Valley Alternative, San Bernardino County, California which is in progress, and the Economic Analysis of the Minerals Potential of the East Mojave National Scenic Area; California, the USBM studied mineral deposits and estimated the potential impacts of mining in a segment of the California desert; the 8.7-million-acre WMMA, an area which includes the 1.2-million-acre Desert Tortoise Priority Habitat (DTPH). In addition, this information is intended to assist administrators, legislators, and the concerned public in understanding the economic importance of mineral resources in the California desert, especially that portion designated as the WMMA. See figure 1.

Jan 1, 1993

Improve the safety of salt mine workers by providing a means for quickly identifying areas within the mine that?s how an increased potential for gas and salt outbursts. Approach Outbursts occur in salt mines when a high-pressure pocket of gas is intercepted during the mining process, resulting in a sudden and sometimes catastrophic expulsion of gas and salt. In one case, the amount of gas released through such an event caused an explosion that resulted in five fatalities. The U.S. Bureau of Mines has designed and developed a gas outburst prediction system that can quickly determine the potential instability of areas within rock salt mines. The determination is based on noise measurements obtained from samples of the salt as they are dissolved in water. This system improves upon technology currently available because it provides information in only a few minutes instead of in several days. In addition, present prediction systems are not only time consuming, but expensive because they require laboratory conditions and highly trained personnel to operate them and determine results.

Jan 1, 1989