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By W. A. Stickney

As part of a Bureau of Mines program to investigate recovery of manganese (Mn) from low-grade materials, laboratory studies were made of four samples of mill rejects: Three from Montana and one from Peru. These studies demonstrated that certain mill-waste products can be a potential source of manganese. Both manganese oxide and carbonate minerals were recovered by flotation in an acid circuit with a fuel oil-tall oil emulsion as collector. Sintering) required to prepare a physically acceptable product, also was used as a method of beneficiation. In addition to being low-grade, some of the samples presented problems of intimate mineral association and complex textures.

Jan 1, 1960

A Helix Pressure Gauge to Indicate roof bolt loads was designed, fabricated and field tested. The gauge indicated loads between 3,000 and 15,000 pounds with a ± ten per cent error. The coat of fabrication of the gauge was estimated to be $3.39 including an assumed overhead and profit per indicator for a series production of 5,000 unite. The unit can be read on a bolt to within ± 1,000 pounds load from a distance of twenty feet.

Jan 1, 1974

By G. W. Jones

Gas analysis is of great practical value to the combustion engineer as a guide in the proper deli and operation of power and heating plants. The automotive industry, however, has made little use of gas analysis in the design and construction of engines. Tests4 made by the Bureau of Mines have shorn that for the average motor vehicle approximately 30 per cent of the heat value of the gasoline passes out in the exhaust as incomplete-combustion products. The tendency at present is to pay more attention to ease and flexibility of operation than to efficiency of combustion. However, neither condition can be fully realized except where each cylinder gets a mixture of the same composition - that is, when certain cylinders do not "load up" with gas at the expense of the others. When this occurs, due to some of the cylinders having too rich a mixture while in others it is too lean, it is impossible to get efficient combustion from the fuel used. Gas analysis enables the engineer to determine the quality of the mixture fed to the different cylinders with a high degree of precision. Briefly, the method consists in making an analysis of the exhaust gas from each cylinder while the engine is in operation.

Jan 1, 1924

By Arnold B. Hubbard

A thermal decomposition study of the kerogen in three Colorado oil shales was made at different temperatures by heating the shales in the absence of oxygen at atmospheric pressure and measuring the decomposition products (gas, oil, and bitumen) formed. From these data the specific reaction rates, "k", for the thermal decomposition of kerogen were determined for each temperature studied, making it possible to calculate the time required to accomplish a given amount of decomposition within the temperature range. The influence of temperature on reaction rates was presented by plotting the data according to the Arrhenius equation, thus providing a means of estimating the values of "k" for any temperature within the range of this study. It was found that the specific reaction rates for the thermal decomposition of the kerogen in the three sampler were comparatively equal at corresponding temperatures.

Jan 1, 1950

By E. P. Youngman

This paper is one of a series of digests of foreign mining legislation and court decisions that is being prepared in advance of a general report relative to the right of American citizens to explore for minerals and to own and operate-mines in various foreign countries. This interpretation of the mining laws of Greece was prepared from information furnished by Ralph B. Curren, American assistant commercial attache, Athens, in reply to a questionnaire of the United States Bureau of Mines, transmitted through the courtesy of the commercial laws division of the Bureau of Foreign and Domestic Commerce. INTRODUCTION In his report,3 Mr. Curren states that the source of his information was the Director of Mines of the Greek Ministry of National Economy and the Mining Code of Greece, which was, compiled from existing laws in 1929,4 and which has since been modified by several acts of Parliament.

Jan 1, 1932

By Wm. F. Netzeband

The purpose of this paper is to present to the operators, in other districts a detailed description of the ruining method used and the results obtained to exploiting one of the zinc-lead deposits of the Kansas-Oklahoma-Missouri district. No. 1. mine is located in the heart of the town of Picher in the extreme northeast corner of Oklahoma. HISTORY The first prospect drilling was done at No. 1 mine late in-1914, and shaft sinking was started early in 1915. Sufficient ore was developed to start construction of the mill in April, 1016, Production begin in August, 1916, and the mine s been producing, except for short periods, to the present time. The property was originally a 40-acre tract, but additional properties have been consolidated with the original one until the mine now covers 200 acres.

Jan 1, 1929

By J. Douglas Causey

In 1986, at the request of the Bureau of Land Management, the U.S. Bureau of Mines studied the 7,940-acre Southern Otay Mountain Wilderness Study Area (CA-060-029), and the 5,750-acre Western Otay Mountain Wilderness Study Area (CA-060-028) in order to evaluate their mineral resources. The wilderness study areas are located in San Diego County, CA, about 20 miles southeast of San Diego. No mineral resources were identified in the Southern or Western Otay Mountain Wilderness Study Areas, based on literature, field observations, and sample results. The wilderness study areas are underlain by a complex blend of Late Jurassic, moderately metamorphosed sedimentary and volcanic rocks. Evidence of mineralization is not obvious.

Jan 1, 1987

By John Ward Smith

The Bureau of Mines drilled Wyoming Corehole No. 1 in Sweetwater County, Wyo., to sample Green River Formation oil shale. Core obtained was assayed for oil yield to determine richness and stratigraphic distribution of oil shale in the deposit. Oil shale in place at Wyoming No. 1 site represents over 200 million barrels of oil per square mile. Additional data useful in evaluating the deposit, including generalized stratigraphy and mineralogy, detailed lithologic descriptions of the core, rock specific gravity, and bore-hole logs, are presented with the oil-yield data. The sampled Wyoming oil shale resembles Mahogany-zone oil shale in rock properties and gross mineralogy. A statistically derived equation relating shale density to oil yield for the Wyoming deposit compares with a similar relationship valid for the better known Mahogany-zone oil shales in Colorado and Utah. A density log from Wyoming Corehole No. 1 is calibrated for direct oil-yield logging. The alternating rich and lean beds of shale at this site may permit creating the permeability necessary for direct production of shale oil from the shale in place.

Jan 1, 1968

By William W. Elmer

This paper, describing the mining method at the Black Butte quicksilver mine, is one of a series of papers being prepared by the U. S. Bureau of Mines on mining practices, methods, and costs in the various districts of the United States. It is presented to show the mining practice and costs in the successful treatment of low-grade quicksilver deposits. The operation discussed is an excellent example of w1-pat can be done in working a limited tonnage of low-grade ore under sound management. The Black Butte mine is situated at Black Butte, Lane County, in the southern part of the State of Oregon, 17-1/2 miles from Cottage Grove -- a station on the Siskiyou branch of the Southern Pacific Co. The Black Butte mining district lies in the foothills of the Calapooia Mountain Range, which connects with the Cascade Range on the east and with the Coast Range on the west. The elevation at '.lie reduction plant is 1,000 feet above sea level. The apex of Black Butte Mountain, or which the mine is situated, has an elevation of 2,700 feet. The district possesses exceptional natural facilities infrequently met with elsewhere for the mining and reduction of cinnabar ores. Several factors which contribute to the unusually low mining costs are:

Jan 1, 1930

By B. R. Mohal, F. F. Aplan, S. Chander

"The wetting behavior of coal has been determined in the presence of nonyl and octyl series of nonionic surfactants containing polyethoxy groups of different sizes. The wetting behavior was determined by a modified Walker technique and contact angle measurements. The results show that the wetting rate of coal varies with coal rank, structure of the hydrocarbon chain and number of ethoxy groups in the hydrophilic group of the surfactant. A close relationship has been observed between the wetting rates and the short-time advancing contact angles.INTRODUCTIONNonionic surfactants are used in many applications to improve wettability of solids. They can be used as dispersing agents [ 1 ] or dust suppressants [ 2-5] and to control the flotation, flocculation, filtration and flowability of particulates. This study was undertaken to study the effect of a series of nonionic surfactants on the wetting behavior of coal. Two series of surfactants, namely, ethoxylated nonyl and octyl phenols were used. The nonyl phenol series contains a linear hydrocarbon chain containing nine carbon atoms ( CH3 ( CH2 ) 8-C6H4-( OC2H4 )""' where n is the number of ethoxy groups). The octyl phenol series contains a branched hydrocarbon chain containing eight carbon atoms ( ( CH3 ) 3CCH2C ( CH3 ) 2-C6H4-( OC2H4)"").Initial wetting rates - modified Walker techniqueWalker et al. [ 6] developed a sink test to determine the wettability of coal particles. In this technique, coal particles are dropped individually onto the surface of surfactant solutions of different concentrations, and the most dilute concentration in which coal would sink ""instantaneously"" is determined. This technique is a variation of a procedure initially developed by Draves and Clarkson [ 7] to determine the effect of surfactants on wettability of cotton fibers."

Jan 1, 1989

In this U.S. Bureau of Mines report, two drill-split mechanical excavation mining system concepts are described, casted, and cost compared with conventional drill-blast mining systems. The concepts for the two drill-split mechanical excavation mining systems presented are (1) a method for steeply dipping narrow veins 0.6 to 1.2 m wide and (2) a longwall method for fiat-lying tabular ores. In the proposed systems, 70 to 80 pet of the ore is disposed of underground as backfill. For sortable ores, face area crushing, sorting, and direct stowage of run-of-mine waste and low-grade ores are proposed. The underground sorting and stowing of waste reduce materials handling, processing, and waste disposal costs by reducing the quality of ore transported to the surface by 70 to 80 pet (by volume). Because many of the tools and techniques proposed for use in these systems have little or no historical mining industry use, cost assignations are heavily influenced by engineering judgments and presented as prefeasibility-level cost estimates. These estimates, presented as discounted-cash-flow-rate-of-return (DCFROR) values, show the proposed systems to be at least as profitable as, and in some cases 50 pet more profitable than, conventional drill-blast mining.

Jan 1, 1994

By Irving Wender

This report describes Bureau of Mines experiments and reviews the work of others on the exposure of coal and coal-derived products to gamma rays and some other types of radiation. Results are presented on tests of three bituminous coals and a lignite that had been pulverized to minus 200-mesh particles and exposed to 1,000 megaroentgens of gamma irradiation from spent-fuel elements of a nuclear reactor. Of about 20 chemical and physical tests in Bureau work, only mass spectrometry of gases evolved during vacuum pyrolysis of the coals to 450° C gave results indicating differences in the irradiated and unirradiated samples. Mass-spectral distribution curves for CO and CO2 evolution showed fewer irregularities (reversals of curvature) for irradiated coals; thus, mass spectrometry appears to be the most sensitive method for determining radio-induced changes in coal. It is concluded that coal is not significantly altered by gamma irradiation owing to the resistivity of its highly condensed ring structure. High-level gamma irradiation, therefore, is unlikely to prove advantageous in coal processing and utilization. Specially treated coals, because of resistivity of coal to radiation damage, may be useful as an absorbent in processing radioactive wastes.

Jan 1, 1968

By Frederick W. Horton

With large deposits of low-grade molybdenum ore and a latent market for molybdenum, which with development might perhaps equal that for tungsten, the United States has for years made no pro- duction of molybdenum ore worthy of mention. In fact, during the decade previous to 1914, there was no output of molybdenum ore in this country except in 1905, 1906, and 1907, when a few small lots of molybdenite and wulfenite were marketed." To ascertain why this possible source of economic wealth should remain undeveloped, the United States Bureau of Mines undertook an investigation in 1914, with a view of assisting the establishment of a molybdenum industry in this country. A preliminary review of the situation showed the following conditions: Briefly there was a lack of any considerable demand for molyb- denum for the one known use that might consume any large tonnage of it, that is, for the manufacture to certain alloy steels to which molybdenum imparts properties roughly similar to those produced by tungsten. It was at once evident that the market for molybdenum in alloy steels must be developed, or that extensive new uses for the metal must be created, before the demand would be sufficient to war- rant any extensive mining of molybdenum ore. Investigation showed that one of the chief factors in retarding the development of any demand for molybdenum by the alloy-steel trade was that manufacturers who might use, or might investigate the possibilities of using, the metal were kept out of the market by the fear of not being able to obtain steady supplies. On the other hand, those who might be interested in the development of some of the extensive low-grade molybdenite or wulfenite deposits in this country were prevented from doing so by the small visible demand and the fear that any large production would glut the market. Owing to these conditions the mining of molybdenum has in the past been confined almost entirely to small-scale operations on high-grade streaks of molybdenite ore, and the methods of recovery have been limited largely to cobbing and hand picking.

Jan 1, 1916

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 W. T. Millar

Field reconnaissance and laboratory tests on clay from South Windsor, Hartford County, Conn., indicate that the clay is suitable for lightweight aggregate raw material. Exploration of the deposit supports the conclusion that the reserves of clay are sufficient for economical mining operations to produce lightweight aggregate. Preliminary tests indicated that the clay has a short bloating range. Initial expansion occurred at 2,000° F, and at 2,100° F the clay was slightly overfired and sticky. Rotary kiln tests verified the preliminary data, and these tests showed that the clay would make a good lightweight aggregate if the processing temperature and the kiln feed sizes were closely controlled. Lightweight concrete made from the processed aggregate had properties comparable to those of concrete made from a commercial clay aggregate.

Jan 1, 1964

By Clarence O. Babcock

This report describes the results of Bureau of Mines laboratory and preliminary field tests on a rock bolt of helical shape. The flexible construction allows the bolt to maintain a more stable load level than is possible with a straight bolt. Bolt load changes resulting from anchor slippage, blasting shock, or changes in mine geometry with mining advance are minimized. Preliminary field tests were performed at the Kaiser Steel York Canyon mine where the load changes of straight and helical bolts were measured using a vibrating-wire load gage. The field tests were performed to establish the viability of the concept of a helical bolt. The practical usefulness in terms of performance and economics remains to be shown. The change in bolt load for the flexible bolts was one-third that for the straight bolts. There were no malfunctions of the gage, and the bolts maintained a more uniform load than the straight bolts used as controls.

Jan 1, 1978

By J. H. Wiggins

"The tests described below were conducted by the Bureau of Mines at a lease in Oklahoma on installations designed to decrease evaporation losses of crude oil Pram storage tanks. Use of the lease was granted by the Oklahoma Producing and Refining Corporation of America. Tankage was obtained through the courtesy of the Parkensburg Pig and Reel Co. The purpose of the installations and tests was to demonstrate the value of making crude-oil storage tanks gas-tight, rather than to determine the amount of evaporation in any one type of tank. None of the tanks used were absolutely gas-tight, but one of them was very nearly so. They comprised a tank of the ordinary open type with an 18-inch manhole, a tank with a ""4-inch vent"", a tank with a ""smaller vent"", and a tank which had only ""pin holes"" through which air and vapor could pass freely. On the last two tanks any excess pressure was taken care of by an automatic differential pressure regulator.The results obtained in these tests indicate that tight tankage will soon pay for itself. They will not, however, serve as a basis on which a producer can compute the actual number of days necessary for tight tankage to pay out, because the oil used was exceptionally volatile. It is probable that the average evaporation loss in the Mid-Continent field is at least one-half as great as that shown by these tests, and if this is true, the saving that would be effected by providing tight tankage on the lease will undoubtedly justify the expense. The installation of evaporation-proof tanks on the lease has been delayed by the failure of production managers to realize, first, that their evaporation losses are enormous, and, second, that they can practically eliminate these losses by a simple and inexpensive installation."

Apr 1, 1921

By C. E. Jordan

The fundamental properties of dielectric separation were studied to provide insight into the design and operating characteristics of a dielectric separator. Force equations on mineral particles were derived and evaluated experimentally. Responses to variations in the electrical voltage and frequency, feed rate, particle size, dielectric fluid, and dielectric constant were tested theoretically and experimentally, using a 5-cm-diam dielectric separator. High-dielectric mineral recovery was proportional to the calculated effective dielectric force volume (EDFV) that surrounded each drum-electrode wire. Electrode spacing was the most sensitive design parameter; spacing of less than 0.4 cm was required for a good separation. Dielectric separation was effective for separating minerals with dielectric constants that differed by approximately 2 or more.

Jan 1, 1985

By W. K. Kleysteuber

This report covers the design and testing of a novel bulk materials conveying device by the Bureau of Mines. The transport concept of the device is to create a traveling wave with a steep front so that the bulk material slides and cascades down the front of the wave with some horizontal motion. Ideally, the front should act like a continuous chute. The concept of moving bulk materials along a belt without any forward movement of the belt itself was demonstrated. The conclusions reached were that the mechanism as designed could not overcome the inherent major disadvantages that would make the undulatory conveyor suitable for practical applications.

Jan 1, 1974

By Thomas Brunsing

The program was carried out to develop deep kerfing and core breaking techniques to be incorporated into the design of a field prototype hard rock mining machine. The field machine is designed to mine non-abrasive bedded deposits up to 20,000 psi in uniaxial compressive strength. The mining technique involves cutting approximately 2 ft deep parallel kerfs spaced 2 ft apart in either a horizontal or vertical direction and subsequently breaking out the cores so defined. The prototype machine is intended for demonstration of the technique in a quarry or equivalent field environment. The program was aimed at minimizing the required kerf width, obtaining reliable breaking within that kerf width and determining cutter blade requirements necessary to achieve a mining rate of 20 ft3/min. Full scale breaking experiments and 1/2 scale kerfing experiments were employed to evaluate the system. High strength concrete test specimens were used to simulate the rock being cut and broken. The test results indicate the kerf/break technique can achieve the desired mining rate by utilizing two 7 ft diam blades to cut 2 in. wide by 24 in. deep kerfs. A lateral load applied at the base of the kerf (base shear) was selected at the core breaking technique to be employed by the full-scale prototype machine.

Jan 1, 1983