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By William H. Pomroy

Spontaneous combustion fires involving high-sulfide-content ores are a relatively infrequent yet serious safety hazard in mining. They are also the cause of lengthy mine shutdowns because they typically occur in areas of a mine where abundant fuel material is present but which are inaccessible for fire fighting. This Bureau of Mines report describes research to design, fabricate, and test in the laboratory and field a system that warns of spontaneous combustion fires in metal mines. Overall performance of the detection system was found to be satisfactory, in that the system was capable of reliably detecting low levels of combustion products believed to indicate the preflaming stage of spontaneous combustion in metal mines. Installation of similar systems in mines with a high risk of spontaneous combustion is recommended. Principal operating problems and recommended corrective actions are also discussed.

Jan 1, 1987

By John Nagy

Large-scale tests in the U.S. Bureau of Mines Experimental Coal Mine show that the explosion hazard of coal dust on shuttle-car roadways can be con-trolled by proper application of water, dry rock dust, a saturated solution of ammonium phosphate, or mixtures of water or the water-phosphate solution with rock dust. The experiments were made with loadings of 1.0 and 5.0 pounds of mine size coal dust per linear foot of entry, and with a 3-or 4-inch-thick layer of coal rubble on the floor, The data from the tests with mine-size coal and rubble are comparable. The water contents of the dust loading were determined from samples collected just prior to initiation of a gas-air mixture in an ignition zone at the face Dust samples were collected 1 inch deep from the coal-rubble deposit. One experiment was made with the dust in the coal rubble bound with latex applied as a water solution by spray. The binding action was inadequate and explosion propagation was obtained.

Jan 1, 1970

By S. J. Broderick

[The term "nonmetallic minerals,? as commonly used in the mining industry, refers to those minerals of industrial importance that are mined essentially for uses other than for the metals contained. The field comprises several hundred minerals of industrial importance, of which 70 have been adequately described in the textbook Industrial Minerals and Rocks.3/ A few of the more important nonmetallic products are sand and gravel, salt, phosphates, clays, refractories, linestone, and cement materials. Some of tic minerals, such as bauxite and pyrolusite, have both metallic and nonmetal is applications, but in this report only the nonmetallic mineral phases are considered. In the organic field of nonraetallics only coal is considered, as, the, others - petroleum, natural gas, natural bitumens, and hydrocarbons - are of no importance in water softening.]

Jan 1, 1941

By Kyei-Sing Kwong

The U.S. Bureau of Mines investigated the synthesis of advanced ceramics (SiC+AlN, SiAlON, SiC+A1203, and Si3N4+AlN) from natural clays (kaolin, halloysite, or montmorillonite) by an intercalation and heat treatment method. This process includes the steps of refining a clay, intercalating organic chemicals into its layered structure, drying the intercalated mixture, firing the treated structure at certain temperature ranges in controlled atmospheres to form desired compounds, and grinding the loosely agglomerated structure. Focus of this research is to economically process advanced ceramic structures from abundant natural resources. The advanced ceramic phases produced in this simple treatment are homogeneously distributed at the nanostructure level, and may potentially lead to cost effective manufacturing processes. The intercalation of clay was confirmed by X-ray and BET analyses. The evolution of chemical compositions during carbonization reactions and carbothermal reduction was investigated. The characteristics of refined clays and synthesized powders were studied. Advanced ceramic composites/solid solution have been produced from intercalated clays, without the presence of other compounds.

Jan 1, 2010

By Stanton L. Tainter

When the disruption of gold mining stopped the usual source of siliceous flux needed by copper smelters , sandstone copper deposits in northern Arizona offered possibilities as a source of the flux during the war emergency . The Federal Geological Survey , while making a comprehensive survey of sandstone copper deposits , investigated the Warm Springs mining district in northcentral Coconino County in August 1943. A month later , J. H. Hedges , chief of the Tucson Division , Mining Branch , Bureau of Mines , examined the operations in connection with an application for an access road . Both investigations concluded that the district , as an emergency source of copper-bearing siliceous flux , had considerable merit , provided high prices for copper continued in effect . Early in 1944 , V. M. Ryan and S. B. Atherley requested assistance from the Bureau in exploring various deposits on their property . The Bureau / drilled 152 holes , aggregating 3,756 feet , on the Petoskey and Mackin groups of claims . This report is based upon churn drilling done under contract from October 7 to November 25 , 1944 .

Feb 1, 1947

By J. F. Shaw

MINE fires are usually extinguished by constructing seals in the approaches to the areas to exclude air from the fire areas, which smothers the fires in an oxygen-depleted atmosphere. Seals should be substantially constructed and made as nearly airtight as possible and should be provided with a sampling pipe so that samples of the atmospheres behind the seals may be collected at regular intervals. Methods of constructing seals and of sampling and analysing mine atmospheres are fully described in Bureau of Mines publications. (1, 2). Information obtained on the composition of atmospheres behind fire seals is helpful in determining if a fire has been extinguished or if there is any danger of an explosion when a fire area is being sealed or unsealed. The progress of a mine fire can best be determined by studying percentages of carbon dioxide, carbon monoxide, and hydrogen in the atmosphere behind the seals. Hydrogen will be formed in a bituminous- or subbituminous-coal mine when the temperature exceeds 480° F. and in an anthracite mine when the temperature exceeds 660° F. (3). Carbon monoxide and carbon dioxide are both products of combustion of coal, wood, or other organic compounds. The presence of carbon monoxide has long been accepted as an indication of a mine fire. A sealed fire area should not be reopened until the carbon monoxide has disappeared. Trends in the percentage of carbon dioxide are also useful in determining the status of a mine fire. Carbon dioxide is sometimes liberated by rock strata. In this case, carbon dioxide in the atmosphere behind a seal will be from two sources-the rock strata and the fire. When the, fire is extinguished, carbon dioxide will be liberated from only I source, the rock strata, and when the percentages of carbon dioxide are plotted, the slope of the curve will not be as steep as when this gas was being liberated from 2 sources. If the only source is the fire, the percentages of carbon dioxide will gradually decrease after the fire has been extinguished. By studying analyses of a mine-fire atmosphere, it is possible to determine if the atmosphere is explosive; if the mixture is capable of becoming explosive when mixed with air; and if the mixture can be made nonexplosive or be prevented from becoming explosive by being mixed with an inert gas. These factors can be computed mathematically or determined graphically. The mathematical calculations advanced by Ash and Felegy (7) are discussed, and graphical solutions of their equations are presented. It is believed that the graphical solution will be extremely helpful in determining the characteristics of a mine-fire atmosphere when fighting a fire, because the results can be obtained in a matter of minutes, and there is less likelihood of an error being made under the stress incident to control efforts. The experimental and theoretical work upon which the formulas are based have been adequately described and are not discussed at this time (5) (6).

Jan 1, 1955

By W. E. Dennis

"INTRODUCTION The strategic importance of zinc warranted investigation of the Silver Eagle zinc prospect, which was first examined by an engineer 3/ of the Bureau of Mines in January 1943.From October 12, 1943, to March 16, 1944, the Bureau explored the deposit by trenching, core drilling, and sampling to establish the amount and grade of ore and to test for the presence of sulfide-ore minerals at depth.ACKNOWLEDGMENTSIn 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 samples and performs beneficiation tests. Both these branches are under the supervision of Dr. R. S. Dean, assistant director."

Oct 1, 1946

By T. M. Ruff

The U.S. Bureau of Mines has developed a portable, inexpensive teleoperation system for mobile hard-rock mining equipment. The system was tested on a compact loader-trammer in a simulated stope. The teleoperation system includes radio remote control and computer-assisted navigation. A recent enhancement includes video cameras mounted on the machine to provide visual information to the operator. This system allows the operator to remain in a safe location while operating the machine from a distance, thus increasing both operator safety and mining productivity.

Jan 1, 2010

By M. H. Rinkenbach, C. A. Taylor

The detonating compound cyanuric triazide was discovered*** and patented**** by Erwin Ott, and on account of his claims, the Bureau of Ordnance, U. S. Navy, desired more complete data, so an investigation was made. The results obtained were such that the Bureau of Crdnance recommended publication thereof for the benefit of the explosives industry. Some of the patent claims regarding cyanuric triazide are as follows: 1. It is not poisonous in contradistinction to fulminating mercury and lead azide. 2. In contradistinction to the hitherto employed priming agents it is fusible, and its fusion point (94°C) is so low that the product melted by a single heating in water or steam bath, can be poured without danger in the capsule shell. It solidifies therein after cooling, and shows the density of 1.5. 3. It has been determined that the cyanuric triazide, in spite of its very much higher priming actions, is much less brisent then ful- minating mercury and lead nitride. 4. The chemically pure cyanuric triazide (C3M2) constitutes colorless crystals melting at 94°0., and is not volatile. It is not affected by cold water, and only slowly saponified by hot water. It is relatively insensitive to friction and not too strong concussion, but explodes by impact or when hea ted to 170°C., or when heated suddenly. It is not more sensitive to friction and shocks then fulminating mercury. 5. The preparation of the triazide is preferably carried out by acting with an excess of sodium azide in an aqueous solution; in the cold, on cyamric chloride gradually suspended in the said solution.

Aug 1, 1923

By R. V. Ramani, K. V. K. Prasad

"This paper was the subject of a cross-disciplinary presentation under the chairmanship of Dr A.M. EdwardsManagers need quality information for effective decision making. This demand, at the present time, is being fulfilled by the increased use of computers via information systems, decision support systems and management information systems. The idea of incorporating intelligence into computers to aid decision-makers has been evolving for over two decades. In recent years, significant progress is reported on applications to business and sciences. In engineering functions, the Artificial Intelligence approach that seems to have great potential is the application of Knowledge Based Systems.The primary objective of this paper is to identify domains in mining engineering where application of knowledge based systems could be beneficial. Incorporation of the expertise required during the analysis and interpretation stages of an engineering design problem through knowledge based systems is recognized as an area of significant benefit. To this end, the components of knowledge based systems for mine ventilation and strata control design are described. The potential applications and limitations of knowledge based systems are outlined. IntroductionCorrect decisions are the key to success in any enterprise. Scope of decisions varies with the echelons of management hierarchy. The decisions of top management are strategic, relating to the long-term future of the organization. In a mineral organization, these deal with such issues as the acquisition of a new mineral property or the diversification of the business to exploit additional markets. At the operational level, a manager is concerned with decisions pertaining to day-to- day eventualities related to production activities and other short-term needs. In either case, the prerequisite is the timely availability and use of information. The difficulty involved in decision-making depends on the situational aspect. In. many cases, the decisions to be made under given conditions are fairly straight-forward and standard. This may be due to experience gained from decision-making in similar situations in the past. In fact, many decisions in operations management are either repetitive or routine."

Jan 1, 1989

By Alan R. Buehler

In 1986, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied part of the 256,430-acre Alvord Desert and part of the 22,240-acre East Alvord Wilderness Study Area (OR-002-074 and OR-002-073A, respectively), in order to evaluate their identified mineral resources. The study areas are located in Harney and Malheur Counties, OR, about 25 mi northeast of the small village of Fields. There are no mines, prospects, or identified mineral resources inside the study areas. Basalt flows within the study areas contain chalcedony-lined vugs and banded agate which may be of interest to rock hounds. An ignimbrite flow contains perlitic material, but crystalline contaminants make it unsuitable for commercial uses. Lacustrine (lake) sediments contain diatomite and clays, and evaporite crusts contain boron too low grade to profitably mine. Small quantities of common opal and petrified wood occur which might be of possible interest to rock hounds. Some of the petrified wood is black, free of fractures, and polishes well; it may be suitable as backing material for soft, thin, and brittle gemstones, such as precious opal. The lacustrine sediments also contain black, fetid layers which have above background, but economically insignificant concentrations of zinc, cobalt, nickel, barium, iron, manganese, aluminum, and potassium. Large quantities of fine-grained dune sands within the study areas are too far from markets for economic consideration. Ephemeral streams in the study areas contain small amounts of placer gold of no economic interest. The western portions of both study areas are reported to have moderate favorability for occurrences of natural gas, and both study areas are reported to have high favorability for the occurrence of geothermal resources. As of December 1986, oil and gas leases covered 3,100 acres in the study areas.

Jan 1, 1987

By Douglas A. Donato

This Information Circular presents the MULSIM/PC system of numerical modeling computer programs developed by the U.S. Bureau of Mines. This system consists of four programs: PREMUL, the preprocessor or mesh generator; MULSIM/PC, the actual numerical modeling program (number cruncher); MUL3D, a three-dimensional postprocessor; and MUL2D, a two-dimensional postprocessor. These programs were specifically designed to operate on IBM-compatible (MS-DOS-based) personal computers for easy transfer of this technology to the mining industry and academia. MULSIM/PC uses a subvariation of the boundary-element method, namely, the displacement-discontinuity technique, for linear-elastic geomechanical analysis of mine plans in one or two parallel underground tabular deposits. Results calculated by this technique include stresses and displacements as they relate to changing mine geometries and materials. In addition to describing the MULSIM/PC program and its features, and providing a detailed example model, this report also documents the associated preprocessing and postprocessing programs that are part of the MULSIM/PC system. User's guides for all the programs are contained in the appendixes following the main report.

Jan 1, 1992

By J. H. Maysilles

The Bureau of Mines, U.S. Department of the Interior, is investigating several types of low-grade uranium deposits. Projections indicate that an increased percentage of future production will be derived from such sources. One material studied was from the Coso Mountains of California; this material contained 0.04 to 0.12 percent U3O8. The deposit contains at least two distinct types of mineralization. The material representing the bulk of this deposit was amenable to acid leaching; 80 to 85 percent U308 extraction resulted from leaching with 20 to 40 pounds per ton of sulfuric acid. No oxidizing agent was required. This ore fraction could be treated by either agitation or percolation leaching. Uranium recovery and purification from the acid leach solution was accomplished using anion exchange followed by precipitation with hydrogen peroxide and ammonia. The second type of mineral was very refractory to acid leaching; a maximum extraction of only 44 percent was obtained with sulfuric acid. Nitric and hydrochloric acids were ineffective also.

Jan 1, 1978

By James W. Townsend, William H. King

"INTRODUCTION As a byproduct of its mineral investigation program, the Bureau of Mines has developed a number of operating devices and techniques worthy of note. This paper, prepared under the direct supervision of Paul T. Alisman, chief, Salt Lake City Division, Mining Branch, and under the general supervision of Lowell B. Moon, chief, Mining Branch, reports upon ore such technique.The Wright borehole-surveying instrument developed at the Homestake mine, Lead, S. Dak., has been described in several publications. 3/ For the benefit of those to whom the publications are not available, the instrument is described here. However, this article will be concerned mainly with the technique developed by the Federal Bureau of Mines for using the instrument.In the use of the Wright borehole-surveying instrument, it was found advantageous to develop a standard practice of operation covering type of film, preparation and care of film, loading film in instrument, placing instrument in container, exposure time, unloading film from instrument, development of film, and determination of dip and strike from film impressions."

May 1, 1947

By J. B. Janus

This report, the 22d in a series, gives analytical data showing composition and quality of tipple and delivered samples of coal collected during fiscal year 1972. This coverage lists mines located in 20 States. Ultimate analyses are given for most of the coalbeds listed. Tipple samples were collected by Bureau of Mines engineers at tipples as coal was being loaded into railroad cars or trucks. The deliveries were sampled in accordance with instructions issued by the Bureau of Mines, and the samples were analyzed in the Bureau laboratory at Pittsburgh.

Jan 1, 1973

"Introduction.The Bureau of Mines has taken up the problem of determining a method or methods whereby underground compensation insurance rates for metal-mining companies can be equalized in proportion to the underground hazards involved. This study has been started by the writer with the assistance of Mr. I. M. Wolfin* as consultant.The present paper briefly reviews the origin of accident compensation, gives a digest of State compensation laws, and describes types of insurance carriers. This will be followed by study of the basis of premium rate, risk differentials, and cost of compensation insurance to mine operators. These data will be supplemented by an analysis of the accident hazards in different mining methods and practices, and the severity and frequency of accidents classified by time lost and period of exposure to hazard, for different States, mining methods, occupations and nationalities. Attention will be given to standardized preventives for underground accidents in metal mines, and, finally, the classification of underground metal-mining hazard for workmen's compensation insurance premium rating."

Mar 1, 1924

By P. L. Placek

Correlations were made on experimental data for four New Mexico ore series to determine relationships between ore grade and uranium extraction during leaching operations. Such relationships provide information needed to predict the long-range supply of minerals to meet national economic and strategic needs. Results show that other ore constituents and gangue materials in addition to uranium grade influence uranium extraction. In general, tailing grades decrease and uranium extraction increases as both H2S04 and NaCl03 concentrations increase. Terminal emf and terminal pH also were studied. Similar trends appeared for all ores; however, specific combinations of results also were observed for individual ores and ore series. Experimental results indicate that uranium extractions are higher for lower uranium feed grades than predicted by other estimates. Three factors--uranium feed grade, H2SO4 concentration, and NaC103 concentration--were used to design factorial experiments for each ore series. Four additional feed assay factors--V205, Fe, C02, and CaO--were included in regression equations to account for some of the variation in data. The three factorial factors are represented in the regression equations by linear and exponential terms of the form D i'1*G i + Di,2 *e Di, 3*Gi. The four additional assay factors are represented by linear and squared terms of the form Di,*Gi + Di,2*eDi3*Gi. where the Di, ,J are coefficients, the Gi are factors, and the symbol * represents multiplication in computer notation. The interactions of the factors are represented by products of the nonlinear terms for all pairs of the factors.

Jan 1, 1981

By John Gross

"Introduction.Southern Illinois and Kentucky are credited with approximately 90% of the fluorspar production of the United States. A small amount of high-grade acid, spar is obtained from the ore by band sorting; the greater part, however, is recovered by jigs and tables as gravel spar containing approximately 85% calcium fluoride. In the jigging and tabling operations, galena is recovered, and enough silica and calcite are removed to raise the calcium fluoride content of the gravel spar to 85%. However, the removal of silica and calcite results in a large loss of spar. With increasing depth in the mines, zinc sulphide, sphalerite, is encountered in increasing quantity and the removal of this has become a serious problem. While the sphalerite can be fairly well removed from the spar by present milling methods, a marketable zinc concentrate can not be made. The experiments described below were made on fluorspar ore from Southern Illinois, by the mining experiment station of the U. S. Bureau of Mines, at Rolla, Mo., in cooperation with the Missouri School of Mines and Metallurgy.The ore tested contained. 7.3% lead, 27.9% zinc, 35.7% calcium fluoride, 9.5% silica and 4.7%. calcite.Tests and Results. In some preliminary tests it was noticed that a portion of the finely crushed ore adhered strongly to the sample pans, and upon investigation it was found that the adhering material was practically clean spar. By utilizing this property of adhesion 46.8% of the spar was recovered as a product containing 98.3% calcium fluoride. This suggested the possibility of using electrostatic separation."

Jul 1, 1921

By H. William Zeller

The Bureau of Mines performed laboratory research into the effects of a barium-based fuel additive (the "postflame" type) on diesel particulate matter (DPM) emissions. The 5.6-L, six-cylinder test engine is typical of types certifiable for use in underground mines. Test parameters consisted of additive concentration and engine loads, speed, and air intake restriction. DPM emissions, including condensed volatiles, were measured gravimetrically. Also measured were gaseous emissions including carbon monoxide, nitrogen oxides, and hydrocarbons. The fuel additive was effective, reducing DPM up to 75 pct, when used at a concentration of 0.09 wt pct (one-fourth of the concentration recommended by the manufacturer). The additive was most effective at the highest fuel-air ratios, reducing DPM from 400 mg/m3 for untreated fuel to 120 mg/m3. At light loads, 25 pct of full rated, no DPM reductions were measured. Based on these results, the additive is recommended for use in diesel fuel, at a concentration of 0.09 wt pct, to power underground mining equipment as long as certain conditions are met: that a beneficial DPM reduction is verified, that the minimum required quantity of additive is used, and that potential adverse effects such as increased nitrogen oxides are checked.

Jan 1, 1990

By K. C. Dean

Horizontal and vertical air classification systems were tested individually and in simulated tandem use for the recovery of ferrous and nonferrous metals and of other noncombustible and combustible products from shredded urban refuse. The horizontal air system with a larger tonnage throughput was used to obtain preliminary separations, and a smaller capacity vertical system was used as a cleaning device. Air elutriation, magnetic separation, and screening of shredded minus 6-inch municipal refuse recovered 92 percent of the metal in a relatively clean iron product contaminated only by adhering coatings or entrapped materials, recovered 97 percent of the combustibles in a 97-percent combustible product, and rejected 88 percent of the nonmetal noncombustibles. Cleaning of the preliminary combustible fraction produced a 98-percent paper product while rejecting other combustibles (plastics, rubber, textiles, etc.) into a 94-percent combustible product. Retreatment of the preliminary noncombustible fraction produced a relatively clean glass product.

Jan 1, 1971