Search Documents

By Arthur Crowfoot

This paper describing t o concentrating practice of the Phelps Dodge Corporation, Morenci Branch, at Morenci, Ariz., is one of a series of articles on concentrating methods and posts being prepared by the Bureau of Mines. The Morenci concentrator, locally known as No. 6 concentrator, treats 5,000 dry tons of ore per 24-hour day by primary tabling followed by two stages of flotation treatment, at 48-mesh size and 65-mush size respectively.

Jan 1, 1931

By H. William Zeller

The Bureau of Mines is conducting research to determine whether the use of chemical surfactants improves respirable coal dust control and is evaluating laboratory test criteria for selecting effective surfactants. This publication presents the results from wetting effectiveness tests with emphasis on the capillary rise test. The test variables investigated included coal particle size, type of surfactant, surfactant concentration, test duration, and mineral con-tent of the water. In addition to the rise test, measurements of con-tact angle, zeta potential, and sink time for various coal and surfactant combinations were conducted. No significant correlations among the four wetting tests were observed, a surprising result which implies that each test type measures specific aspects of the wetting phenomenon and also that each test type should only be used to select surfactants for specific applications. For example, the rise test shows solution penetration into porous materials, and the sink test discriminates among surfactants for dispersing finely ground materials into suspension. Another important conclusion is that combinations of agents retain their individual wetting properties, allowing mixtures to be for-mulated to perform well in both rise and sink tests.

Jan 1, 1983

By Harmon E. Keyes

Many organizations, including the Bureau of Mines, have made intensive studies of the application of leaching methods to relatively small low-grade disseminated deposits of copper ores, containing both oxide and sulphide minerals. One of the principal difficulties has been to obtain a solvent that could be made at a low cost and would effectively dissolve the copper minerals. Another drawback has been the high initial cost of a plant and the refined type of mechanism ordinarily required by standard practice for carrying out the leaching cycle. The Bureau of Mines has attempted to develop a cheap and efficient solvent that would especially meet the requirements of smaller plants. (See Bibliography.) It has been known that dilute ferric sulphate-sulphuric acid solution is an excellent solvent for most copper minerals, such as chalcocite, bornite, and oxidized forms, but not for chalcopyrite and certain silicates. A method of producing this solution from sulphurous products and waste liquors was developed by the bureau and tried successfully on a test-plant scale at the Southwest Experiment Station in cooperation with the department of mining and metallurgy, University of Arizona, Tucson, Ariz. However, this work did not involve the actual leaching of ores with the solutions thus produced or the cyclic use of the iron solutions in the regenerator cell. Except for certain laboratory tests, in which known impurities were added, no data were available to show the effect on regeneration if accumulations of impurities were built up in the leaching circuit.

Jan 1, 1930

By Richard N. Spencer

This report describes investigations of the economic merits of multiple zone mining and beneficiation versus selective mining of altered Western phosphate rock. The same deposit was considered in both instances and it was assumed that the grade of selectively mined ore was comparable to the grade of the concentrate from beneficiation. The beneficiating scheme used for the investigation was one proved by small continuous circuit operation. All economic factors were found to favor multiple zone mining plus beneficiation. Capital requirements and production costs were lower, and production life of the deposit was extended 4.5 times. The concentrate from beneficiation would be a uniform high-quality feed for acidulation and would be low in stable metallic oxide (R203) content. Such a feed would permit improved plant operating control, and the low R203 would promote more rapid filtration and minimize sludge formation in the phosphoric acid. With the proposed treatment, the concentrate produced by flotation from this deposit would cost about 1.5 times as much per ton as the concentrate produced by classification sizing. Therefore, inclusion of a flotation step in treatment schemes requires an economic analysis for each ore deposit.

Jan 1, 1971

By S. H. Ash

The Pennsylvania anthracite region is composed of four fields, namely, the Northern, Eastern Middle, Western Middle, and Southern. It is in the eastern part of Pennsylvania and is shown on figure 1. The anthracite industry is confronted with a crucial problem of inundation by water impounded in underground pools in many mines and by infiltration of water from streams and pools on the surface (3). The deposits of anthracite in the United States are limited virtually to Pennsylvania, and the difficulties of this industry have been commonly considered as a State problem rather than a national one (1, 4, 6, 7). Anthracite was discovered in Pennsylvania in 1762, and the first mining company was formed in 1793. It was not until 1812 that anthracite began to receive recognition in the Philadelphia market as a domestic fuel, and by 1838 the annual production was nearly 1 million net tons. Since anthracite mining began, mine water has become progressively more difficult and costly to handle because of the extraction of anthracite both underground and along the outcrops of the beds, until at the present time mine drainage is a major anthracite-mining problem. Mine water is handled at the anthracite mines as follows: (a) by pumping, (b) by drainage tunnels, (c) by combination of pumping and drainage tunnels, and (d) by water hoists (hoisting water by means of large buckets) (4, 5,6, 7). This paper covers removal of the water from mines by means of pumping plants. Pumping is indispensable in the production of anthracite (5). The cost of pumping mine water has increased progressively since anthracite mining began. Some collieries have been forced to discontinue mining because of the high cost of pumping.

Jan 1, 1950

By L. Keith Hudson

The purpose of this study is to provide data that demonstrates that the Alcoa flash calciner design can be used for the decomposition of AlCl3?6H2O to A1203. Heat and material valance data for calcination provides data on the partial pressure of HCl in the off-gases. Experimentally determined data for the HCl partial pressure, over solutions expected in producing alumina from clay by the hydrochloric acid process, show that HCl can be absorbed from the off-gases into process solutions to effect crystallization of AlCl3?6H2O.

Jan 1, 1979

By R. R. Lowery

An analysis of three 1-1/4-diam manufactured wire ropes of 6x19 classification was done to identify and describe reference conditions of new rope. Reference condition is of value when examining tested or retired ropes. Measurements of strand and rope pitch and of wire and rope diameter confirmed adherence of all ropes to those construction specifications. Mechanical properties of strength and ductility were determined by accepted methods for the ropes and wires from the ropes. Individual wires from one rope failed to meet minimum wire ductility values. Wire chemical composition varied in average carbon levels, from 0.70 to 0.78 wt pct, and in manganese content, from 0.45 to 0.80 wt pct. One manufacturer's product contained 1 to 3 wt pct Ni and Cr. Heavily wrought pearlitic steel microstructures were porous and contained inclusions. Cold work variations were evidenced by wrought grain width. Recorded anomalies reflected the condition of the manu-factured products. The report provides data that compare the three wire ropes studied, but cannot verify the effects that these conditions or anomalies have on rope service life.

Jan 1, 1983

By Jeffrey H. Welsh

The Bureau of Mines studied the use of computerized, continuous, remote monitoring systems for safety from power system faults in underground coal mines. In this report the need to improve protection against power system faults is documented, and types of faults are identified. The relationship between mine safety regulations and computerized, continuous, remote monitoring is analyzed.

Jan 1, 1983

By G. L. Oldright

In the first Report of Investigations of the present series?(No. 4562) the usual course of progress ill reducing the minerals of low-grade ores to their valuable metallic components had been noted as advancing along two lines to concentrate a usually diminishing percentage of these minerals to a smaller bulk of richer product, and then to smelt the smaller bulk more cheaply per pound of metal produced. Fundamental properties of lead compounds made it difficult to treat much richer lead products than are treated at present in several steps of conventional lead smelting, unless ?marked modifications were made. No limits to the richness of the feed itself' were set by the ore (Scotch) hearth; on the contrary, the richer the feed, the better the results given by the hearth. The natural field of operation of the hearth, as determined by the ores available, was seen to lie in the Central United States, with their lead concentrates containing negligible quantities of precious metals and. with few ores of such metals available for use as fluxes. It was noted) however, that even in its chosen field, the Scotch hearth, or "ore" hearths developed from them, was not always used; the usual smelting practice was followed, at times, of sintering followed by blast-furnace smelting for even rich ores.

Jan 1, 1949

By William C. Cooley

[ ]

Jan 1, 1975

By F. E. Diebold

The wastewater-treatment system of the Anaconda Mining Co., at its Butte, MT., operation has been physically and chemically characterize modeled on a computer and investigated with respect to alternate systems for economic heavy metal recovery. The system involves lime addition to a mixture of acid underground copper sulfide mine water, acid effluent water from the iron induced precipitation of copper from acid leach solution and basic suspensions of solid effluent from a concentrator plant. Experimental chemical analysis and predictive computer calculations shows that the monosulfllte and disulfllte complexes of transition metals (Iron II being dominant) and alkaline earths are 40% of the total dissolved metal load of both acid streams. The suspended solids (30% by weight) in the basic concentrator slurries are dominated by quartz and pyrite and also contain kaolinite muscovite, biotite and undissolved lime. The mixture of these three streams result's in major reductions in concentrations of Al, Cu, Fe, Mg, Mn, Sir and Zn, and a pH >7 with calcium, sodium, potassium, and sulfate being the major dissolved ions. The treatment system has been simulated in the laboratory and accurately modeled on a computer. The computer program, an altered REDEQL-EPAK, is capable of accurately predicting the amount of lime required to reach a desired effluent water. Preliminary research has indicated the usefulness of electroprecipitation as a means of recovering the valuable metal load and providing an EPA acceptable effluent.

Jan 1, 1982

By A. Sainato, S. J. Kravits, G. L. Finfinger

This report describes a project conducted by the Bureau of Mines in which the accurate directional drilling of a borehole was demonstrated with the objective of intercepting a designated target. The project was conducted at Navajo Dam in northern New Mexico at the request of the Bureau of Reclamation. Borehole survey and drill logs are provided in an appendix. The trajectory of the demonstration borehole was designed to intercept a 5-ft-radius target at the final or "punchout" distance of 885 ft. The elevation of the borehole at this distance was within the target; the borehole punchout coordinates were 8.81 ft southwest of the target. As a result of the demonstrated accuracy, the Bureau of Reclamation has contracted the accurate drilling of boreholes as long as 600 ft from the inside of a short tunnel, to control water seepage in the right abut- ment. This resulted in a substantial cost savings compared to the orig- inal plan of constructing a longer tunnel and drilling 150-ft boreholes.

Jan 1, 1987

By T. F. Mitchell

During the investigation or the occurrence of manganese deposits in western United States, Bureau of Mines' examining engineers collected samples from four manganese properties in the Death Valley region, California. These were supplemented by samples submitted by owners of two other properties in the same area. Extensive laboratory tests were made to determine the, amenability of the ores to standard ore-dressing concentration methods. A small sample of high-grade oxide manganese ore from the McWhinney property, San Bernardino County, Calif., was submitted by the owner. Although the sample would sinter directly to plus 48 percent manganese grade, it appeared probable that the ore, if mined in quantity, would be lower in grade and would require beneficiation. Therefore, testing was conducted to remove the chief gangue constituent, calcite. The National Resources, Inc., property (also known as the old Owl Hole mine) is in the Owl Hole Springs district, I mile from Owl Hole Springs, San Bernardino County, Calif., near the southwest corner of Death Valley National Monument. The ore deposits occur as small lenses or ,pockets, evidently .replacements in limestone and granite. Laboratory work was done on a representative sample of orb procured by Bureau engineers.

Jan 1, 1949

By C. A. Taylor, C. E. Munroe

"In blasting the explosion of the high explosives charge is initiated by means of a detonator. Consequently the successful operation of the whole system is, ab initio dependent upon the suitability and efficiency of the detonator used. A considerable number of methods for testing the efficiency of detonators have been devised. In a previous publication*** of the Bureau of Mines many of these were discussed after having been classified as direct and indirect methods.In 1910, W. O, Snelling, then explosives chemist of the Bureau, devised a direct method which depends on the extent to which a hard brittle material of uniform granulation, such as quartz sand, is pulverized by the explosion of the detonator when imbedded in it, and, as a container in which to carry out the tests, he devised the vessel known as the Bureau of Mines sand-test bomb No. 1. A brief mention of his work was made in a paper presented to the Engineers' Society of Western Pennsylvania.****Later Storm and Cope made a very extended investigation of this method using sand-test bomb No, 1. Their paper***** contains a detailed, illustrated, description of sand-test bomb No. 1, with precise specifications of the sand and a minute account of the technique followed, together with a discussion of the data they obtained from the tests in this bomb of 112 detonators representing each of the grades from We, 3 to No. 10, inclusive. The average of results obtained by them are set forth in the following table."

Dec 1, 1923

By Alex C. Smith

This report describes laboratory studies conducted by the Bureau of Mines on the spontaneous combustion of U.S. coals. Approximately 11 pet of U.S. underground coal mine fires are attributed to spontaneous combustion. The relative self-heating tendencies of 24 coal samples were evaluated in an adiabatic heating oven. Minimum self-heating temperatures (SHT's) in the oven ranged from 350 C for a lignite and high-volatile C bituminous (hvCb) coal, to 1350 C for two low-volatile bituminous (lvb) coals. An empirical expression was determined predicting a bituminous coal's minimum SHT in the adiabatic oven based on the coal's dry ash-free oxygen content. Several factors that can affect the self-heating process were also evaluated. The self-~eating tendency of a coal increased when the coal was dried and exposed to humidified air, and was dependent on the particle size and oxygen concentration of the air. A new moderate-scale apparatus is described, in which the self-heating tendencies of larger coal samples, 3 kg, can be evaluated. The minimum SHT's of two coals were determined and the results were in good agreement with those found in the adiabatic oven. Finally, results of a test in the moderate-scale apparatus indicated a strong dependence of the self-heating rate of a low rank coal on the moisture content of the air.

Jan 1, 1987

By D. N. Nilsen

A mathematical modeling method was developed by the Bureau of Mines for the prediction of the principal equilibrium species in the solvent extraction of copper. The use of models for predicting the amount of metal extracted can reduce the amount of experimental work required to characterize a system for purposes such as optimization studies. Models were developed for the extraction of copper from ammoniacal sulfate and carbonate solutions with commercially available extract ants commonly used by industry. Results from laboratory shakeout tests compared well with predictions of the equilibrium concentrations of copper and pH values. For example, the loading of copper onto the solvent was predicted for most cases within ±S pct of the measured values, and the pH to with-in ±O.l pH unit in sulfate systems and ±O.2 pH unit in carbonate systems. Both mechanistic and empirical extraction equations were developed from laboratory data for copper and ammonia. The empirical-based models were slightly more accurate than were the mechanistic-based mod-els. Industrial level concentrations of the aqueous and organic constituents were used in this work. Independent variables included copper concentration, ionic strength, and initial pH of the aqueous phase; extractants, diluents, and their concentration in the organic phase; and temperature.

Jan 1, 1988

By August J. Kwitowski

This Bureau of Mines report summarizes the development of a protective operator compartment for a new generation thin-seam mobile bridge carrier. The developed compartment is commercially available and is currently employed on approximately 15 bridge carriers used in the mining industry. The design of the compartment, which employed human factors engineering and small- and full-scale mockup models, is fully described. Details of the compartment's fabrication, evaluation, and demonstration in a commercial low-seam coal mine are also provided.

Jan 1, 1986

By Daniel S. Witkowsky

The Pollution Prevention Act of 1990 provides few specifics to assist the non-fuel mining and mineral processing industries of the United States in achieving pollution prevention (P2) compliance. The U.S. Bureau of Mines (USBM) recognizes the absence of specific information to reduce pollution impacts from mining and mineral processing of hardrock and industrial minerals. Therefore, the USBM has prepared this publication to help reduce or eliminate environmental pollution and to assure the viability of these segments of the domestic mining industry. This report includes worksheets designed to help operators of mining and milling facilities to establish a P2 program. The report can also be used by citizen and environmental groups, State and local governments, and academia to gain an understanding of P2 as it relates to mining and mineral processing.

Jan 1, 1995

By C. A. Herbert

This paper sets forth the hazards of accumulations of explosive mixtures of methane and air due to inadequate ventilation, the causes of which are discussed as follows: 1. Lack of well-maintained air courses. 2. Air losses due to leaky stoppings, trap doors, and overcasts. 3. Faulty mining methods. 4. Poor supervision. A modified plan of room-and-pillar panel mine development is suggested, which, it is believed, will eliminate many off the hazards of gas accumulations inherent in the present method of mine development. It is also suggested that some water-proofing agent be used on the roof of permanent air-course entries in conjunction with roof bolting to eliminate the detrimental effect of the moisture-laden atmosphere during summer and thus prevent serious roof falls.

Jan 1, 1953

By J. E. Shelton

Flotation tests are described on samples of two lowgrade nickeliferous ores of Oregon and Washington. The sample from the Congress mine, Ferry County, Wash., contained 1.2 percent Ni, occurring chiefly as millerite. The sample from the Shamrock mine, Jackson County, Oreg., contained 2.20 percent Ni and 0.78 percent Cu occurring chiefly as pentlandite, nickeliferous pyrrhotite, and chalcopyrite. The millerite in the Congress ore was concentrated by flotatioin with aulfydric collectors in a series of locked tests to recover 73 percent of the nickel as a 7 percent bulk concentrate. By successively regrinding and floating the bulk concentrate, it was further concentrated to 12.4 percent Ni at a recovery of 59 percent and 21.8 percent Ni at a recovery of 50 percent. Attempts at selective concentration of the copper-nickel Shamrock ore were only partly successful because of the intimate association of pentlandite and chalcopyrite. The nickel concentrate, which contained 86 percent of the nickel, had an analysis of 4.42 percent Ni and 1.03 percent Cu. The copper concentrate had an analysis of 18.8 percent Cu and 1.96 percent Ni and contained 48.5 percent of the copper. A bulk sulfide concentrate contained 92 percent of the copper and 01 per¬cent of the nickel and had an analysis of 4.17 percent Ni and 1.63 percent Cu.

Jan 1, 1956