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By Howard E. Parkinson

Since 1969, the Department of Interior, Bureau of Mines, has carried out communications research. Research has been directed toward developing emergency and nonemergency mine communications. This paper gives an overview of the progress made in the last two years. Particular emphasis is given to the overall program, noise and signal measurements, systems studies, guidelines, products, and demonstrations now being carried on in operating mines.

By Andrew B. Cecala, Robert J. Timko, Alexander D. Prokop

Bag loading and stacking processes are the highest dust-exposure job categories in the metal/nonmetal mining industry.1 To cost-effectively decrease respirable dust levels, the Pittsburgh Research Center of the National Institute of Occupational Safety and Health (NIOSH), formerly of the U. S. Bureau of Mines, designed and tested a system called the Bag and Belt Cleaner Device (B&BCD). [ ]

By D. E. Wolfson

The Bureau of Mines investigated the use of preheated coal in carbonization operations. Liquor yields and coking times were reduced, coke quality was improved, and smokeless pipeline charging to coke ovens should eliminate a serious source of pollution.

Jan 1, 1972

By Fred N. Kissell

Tracer gas decay curves were experimentally obtained in a full-scale model coal mine working face area. The concentration of tracer gas was found to decay in exponential fashion but with a change in slope. This change in slope is attributed to eddy zones in the face area. A simple theory was developed that allows one to calculate the approximate amount of gas in the eddy zones and thus estimate the size of the eddy zones.

Jan 1, 1974

Efficiently clear ice and frozen materials from ore-handling equipment. Approach Compressed air-propane torches that develop a high energy flame jet were used instead of ordinary propane torches. How it Works A high velocity high temperature stream of gases impinges on the ice and frozen materials to both melt and blast them away. This hot gas jet is at 3,000°F temperature and moving at 3,000 feet per second. In the photograph below, the jet is being used to clear frozen taconite from a grizzly. The functions of the compressed air-propane torch are as follows. The air heater assembly, which is mounted on a wand, con-

Jan 1, 1980

Provide a means through which members of the mining community can easily and readily access information on human factors/ergonomics as it relates to mining. Approach As part of a research study aimed at reducing human error accidents in mining the Bureau of Mines developed a computerized information retrieval system which provides relevant human factors or ergonomics information on 19 mining-related special interest categories.

Jan 1, 1988

By E. Aamland

Preparation of high-purity magnesium-yttrium alloys by electroreduction of Y2O3 dissolved in a YF3-LiF bath and the subsequent deposition of yttrium in a molten magnesium cathode was investigated in laboratory-scale apparatus. Parameters such as temperature, current density, and electrolyte density were studied. Electrolysis was conducted in a specially designed MgO diaphragm cell at temperatures ranging from 780° to 970° C. Alloys containing up to 55 weight-percent yttrium were prepared at cathode current efficiencies of 21 to 60 percent. Cell design and operation are described, and some of the limiting conditions pertaining to the method are discussed.

Jan 1, 1973

By Robert F. Chaiken

A quasi-steady-burning channel model is used in this Bureau of Mines study to describe the conductive heat loss from an in situ coal combustor to the surrounding rock strata. The calculated heat losses are significantly greater than those previously estimated, but are still very acceptable from the viewpoint of energy recovery. Approximately 80% to 90% of the heat of combustion of the coal should appear as sensible heat of the gaseous exhaust, with exhaust temperatures in the range of 1,000° to 1,200° C. The effects of burning stoichiometry and channel size on the heat loss are also discussed in terms of the model. Such effects are shown to be compatible with an in situ combustion process even in thin seams. However, these results depend on gas leakage and adverse roof falls not being important factors in deter-mining the heat loss mechanism.

Jan 1, 1977

By Travis Q. Lyday

Fiji has been an independent country within the British Commonwealth of Nations since 1970. It consists of an archipelago of more than 300 islands ranging from tiny coral atolls, cays, and rugged coral limestone islets, to the larger mountainous islands of Kandavu, Taveuni, Vanua Levu, and Viti Levu of volcanic origin. The islands of Fiji straddle the 1800 meridian about 1,800 kilometers south of the Equator in the part of the southern Pacific Ocean known as Melanesia. The production of gold and silver from the Emperor Mine at Vatukoula on the island of Viti Levu, the main island of Fiji, remained Fiji's only metallic mineral producer. Mining began at the Vatukoula site in 1933, producing 124 million troy ounces of gold and 147 thousand troy ounces of silver by yearend 1985.

Jan 1, 1987

By R. F. Waters

The Bureau of Mines developed laboratory-scale processes to recover sodium phosphates and metal values from waste sludges generated by the phosphate treatment of automobile and appliance components. After treatment of the sludge with NaOH, followed by coke or hydrogen reduction and sintering, zinc and lead were recovered as fume; the sinter was separated by leaching into a metallic product, chiefly iron and nickel, and high-purity disodium or trisodium phosphate.

Jan 1, 1971

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

MINE VENTLATION NETWORK ANALYSIS

Jan 1, 1977

By Fred Baldassare, Marcia Harris, Kenneth K. Eltschlager

Surface mine blasting was recently investigated as a potential source of high concentrations of stray gases found in nearby residences of western Pennsylvania. In one incident carbon monoxide was detected in a home and in the other, high concentrations of carbon dioxide were found in a home. Both carbon monoxide and carbon dioxide are by-products of blasting. However, other potential sources of these gases may also exist in a residential setting. In each case, gas chromatography (GC) and carbon isotopic analyses were used to define atmospheric concentrations inside the homes, and to determine the source of a stray gas. Molecular and isotopic analyses provide geochemical evidence as to the origin and source of the stray gas. This paper discusses elements of a stray gas investigation and the analyses necessary to identify the source of a stray gas.

By J. Hanslovan, R. H. King

An investigation of the feasibility of shielding low-voltage trailing cables in underground coal mines is described. Both laboratory and under¬ground installation results are presented. The main objective of shielding is to reduce the electrical shock hazard; however, several problems will be encountered by mine operators who install shielded cables. Parameters related to such items as purchasing, splicing, troubleshooting, safety, and reliability are discussed. Some of these problems can be minimized by changes in cable constructions and shuttle-car reeling-device components. Both SH-C and SH-D constructions are considered.

Jan 1, 1979

By C. M. Frost

Crude shale oil prepared by gas-combustion retorting of Colorado oil shale was hydrogenated over a cobalt molybdate catalyst at an operating pressure of 1,000 psig, temperatures of 781° and 761° F, and liquid hourly space velocities of 0.10 and 0.05 Vo/Vo/hr, respectively. The yields of total liquid products and the amounts of nitrogen and sulfur removed were comparable with those obtained at an operating pressure of 3,000 psig and a liquid hourly space velocity of 1.0 Vo/Vo/hr. Approximately 1.5 times as much gasoline was produced at the lower pressure and space velocities.

Jan 1, 1973

By B. E. Davis

As part of its program to increase the domestic availability of critical minerals, the Bureau of Mines conducted characterization and beneficiation studies on a St. Johns County, Fla., phosphate ore that was mined by borehole mining. Results revealed that the ore from this test mine was mostly sand-size carbonate-fluorapatite and quartz and contained 24.6 percent P205. Concentration by various flotation techniques produced phosphate concentrates that ranged, in percent, from 30.0 to 31.4 P205, 0.73 to 0.80 MgO, and 2.8 to 7.2 acid insoluble. Recovery of the phosphate from the ore ranged from 89.4 to 96.3 percent.

Jan 1, 1982

By D. R. Forshey

The recent occurrence of fatal accidents in copper mines, presumably due to premature ignition of loaded holes by the heat from reacting ammonium nitrate-fuel oil (AN-FO) and pyrite-bearing ores, has led to an examination of this reaction. The reactivity of prilled AN-FO mixtures with pyrite-bearing ores and the effects of water, dilute sulfuric acid, and potential inhibitors on reactivity of the mixtures were evaluated. Initiation of an exothermic reaction was observed as low as 150° F with acid in the absence of inhibitors. Low concentrations of urea, calcium carbonate, zinc oxide, and magnesium oxide were effective in inhibiting the reactivity of the mixtures. The temperatures produced during the reaction of mixtures of AN-FO and pyrite-bearing ores, in the absence of inhibitors, always exceeded the temperature at which electric blasting caps are thermally initiated.

Jan 1, 1968

By E. Morrice

Gadolinium, dysprosium, and yttrium are difficult to electrowin as high-purity liquid metals because of their high melting points (>1,300° C). Samarium metal is difficult to prepare directly by electrolysis because the metal reacts with the electrolyte. In this Bureau of Mines study, the rare-earth metal was electrodeposited on a solid manganese, chromium, or iron cathode to form a low-melting alloy. The alloy was then vacuum distilled to separate the rare-earth metal from the ferrous metal. A typical samarium metal product, obtained as the distillate from vacuum distillation of a samarium-iron alloy, contained 150 ppm oxygen, 80 ppm carbon, and 50 ppm iron as impurities, Gadolinium metal, obtained as a residue from the distillation of a gadolinium-chromium alloy, contained 300 ppm oxygen, 200 ppm carbon, and 100 ppm chromium.

Jan 1, 1969

Detect fires in or near mine shafts, isolate smoke filled areas, and remotely extinguish fire. Approach A system (of sensors, automatic alarms, an aboveground control console, remotely operated ventilation doors, and sprinklers) has been built from off the-shelf components, and fire, tested in two mines. How It Works The system uses three different kinds of sensors that can detect the heat or smoke of a fire and automatically actuate alarms. When the alarm sounds in the control center on the surface, water sprays in the mine shaft and shaft station areas can be remotely turned on to deluge both the inside and the outside of the mine shaft's wooden support structure. To protect miners from toxic fumes, smoke control doors can be closed or opened, either remotely from the control center or directly by miners using the manual or electrical actuators at the door locations. Man doors built into each ventilation door allow persons to pass without opening the main door.

Jan 1, 1977

By R. V. Lundquist

Past reports by the Bureau of Mines have described the extraction of alumina from numerous aluminum silicate materials by the lime-soda sinter process. The results from pilot-plant investigations of six materials, with alumina-to-silica mole ratios from 0.3 to 8.7, indicated a relationship between the alumina-silica ratios and the processing characteristics of the sinter. A series of laboratory tests was conducted to define this relationship. Sinter and leach tests determined that an alumina-to-silica mole ratio of 0.90 or greater resulted in the best alumina and soda recoveries while leaving the leach slurries practically free from any tendency toward gelation. The widely different chemical and mineralogic properties of the various aluminous materials used in compounding the mixes had no perceptible effect on the leaching characteristics of the sinter. The blending of low-cost, high-alumina materials with aluminum silicate materials to give an alumina-to-silica mole ratio of 0.90 or greater would improve alumina and soda extraction and minimize operating problems in the lime-soda sinter process.

Jan 1, 1970

By Fred N. Kissell

Methane flows and pressures were measured in mines in the Pittsburgh, Hartshorne, and Pocahontas No. 3 coalbeds. From the data, the permeability of each of these coalbeds was computed. It was found to depend strongly on the type of coal and on the amount of water in the coalbed, and it was found to increase with time. All of the coalbeds had a high-permeability zone adjacent to the face or rib, and the Pittsburgh bed exhibited directional anisotropy. Surprisingly, little or no overburden effect was observed.

Jan 1, 1972