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By D. B. McGilvra

This paper, describing the mining practices and methods at the Black Rock mine, is one of a series of similar papers on mining methods in the various mines of the United States being prepared by the Bureau of Mines. The Black Rock mine is located in the northeast corner of the Butte district, about 3 miles from the center of the town of Butte, and is owned and operated by the Butte & Superior Mining Co.

Jan 1, 1930

By H. S. Caldwell

A magnesium-base incendiary alloy, containing about 20 percent cadmium, 4 percent aluminum, and 0.5 percent zinc, was investigated in a series of vacuum-distillation experiments to determine the feasibility of recovering magnesium and cadmium as refined metals. Alloys prepared in the laboratory and actual bomb-casing alloy were studied at temperatures of 550° to 750° C. and pressures of 100 to 150 microns. Simple distillation and fractional distillation methods were only partly effective in separating the cadmium and magnesium. They were separated satisfactorily, however, with a special vapor baffle designed to condense the metals selectively. Magnesium and cadmium products were 99 percent pure and together comprised 82 percent of the total condensate. About 17 percent of the condensate was intermediate-grade alloy that could be recycled with new charge and contained about 70 percent magnesium and 30 percent cadmium.

Jan 1, 1959

By V. B. Dale

This is one of a series of reports covering the mineral resources of the Nation. It describes briefly most of the known tungsten deposits in Yuma, Maricopa, Pinal, and Graham Counties, Ariz. Most of those described were examined by the author. An effort was made to determine the position of the various deposits by section, township, and range and to give accurate road direction to each property from a prominent landmark. All available maps have been used in making these determinations, but in unsurveyed areas it was necessary to make approximate projections of subdivisions. The township and range numbers refer to the Gila and Salt River base and meridian.

Jan 1, 1959

By Gerald W. Elger

This report describes development of the fusion-leach crystallization precipitation process for producing a hafnium content feed material for hafnium-zirconium separation plants. Mixtures of zircon, potassium silicofluoride, and potassium carbonate (or potassium chloride) were fused to prepare soluble potassium zirconium hexafluoride-potassium hafnium hexafluoride salts. High extraction of these salts was obtained by countercurrent leaching the fused material in dilute hydrofluoric acid. About one-half of the hafnium was recovered in hafnium-enriched mother liquor by cooling clarified lead: liquor to crystallize most of the zirconium salt. Additional hafnium was recovered from the primary crystals in a multiple dissolution-recrystallization step. Hafnium-enriched oxides having a hafnium-zirconium ratio of more than three times that of zircon were precipitated from the combined mother liquors. The hafnium and zirconium recoveries in the precipitate were 83 and 24 percent, respectively. About 71 percent of the zirconium and the remainder of the hafnium were recovered in potassium zirconium hexafluoride crystals of low-hafnium content.

Jan 1, 1966

By R. G. Sandberg

The Bureau of Mines investigated a hydrometallurgical procedure to recover gold, silver, and byproduct lead from a complex lead-zinc sulfide ore. A ferric chloride (FeCI3) preleach, at 40° C in 6 h, extracted about 50 pct of the zinc and formed insoluble silver and lead chlorides. Subsequent acid thiourea leaching, for 1 to 3 h at 40° C, extracted about 85 pct of the gold and silver. Lead chloride was solubilized from the remaining residue with NaCI brine solution at 55° C in 1 h. Lead metal was recovered from the brine solution in an electrolytic cell with an anion perms elective membrane at a current efficiency of 95 pct and current density of 100 A/m2. Spent FeCl3 leach solution was reoxidized in the anode compartment at a current efficiency between 75 and 95 pct.

Jan 1, 1986

By L. F. Heising

The Bureau of Mines evaluated 191 composites from the central Mesabi Range, Minn., chiefly by reductive roasting and magnetic separation. After reductive roasting and magnetic separation at minus 325 mesh, 28 composites produced concentrates that contained an average of 66.0 percent iron with less than 10 percent silica. Recovery of contained iron was over 90 percent. Natural magnetic material in excess of 5 percent was present in 142 composites. Trial flotation tests were used to evaluate three samples unresponsive to reductive roasting and magnetic separation procedures, and satisfactory concentrates having low silica contents (averaging 6.6 percent) were achieved.

Jan 1, 1965

By R. H. Fewkes

New information on possible resource value of sea floor manganese nodule deposits in the eastern North Pacific has been obtained by study of records and collections of the 1972 Sea Scope Expedition. Nodule abundance (percent of sea floor covered) varies greatly, to judge from bottom photographs from 8 stations and data from other sources. All estimates considered reliable are plotted on a map of the region. Similar maps show the average content of Ni, Cu, Mn, and Co at 89 stations from which 3 or more nodules were analyzed. Variations in nodule metal content at each station are shown graphically in an appendix, where data on nodule sizes are also given. Results of new analyses of 420 nodules from 93 stations, for Mn, Fe, Ni, Cu, Co, and Zn, are listed in another appendix. Relatively high Ni+Cu content is restricted chiefly to four groups of stations in the equatorial region, where group averages are 1.86, 1.99, 2.47, and 2255 weight percent. These and a few other areas may warrant more exploration. It is hoped that this report will stimulate new interest in North Pacific nodule deposits and that the maps and quantitative data will aid future exploration.

Jan 1, 1981

By A. S. Moore

The Bureau of Mines is doing research and development work on removing acid-gas impurities from synthesis gas made directly from coal. Since conventional gas scrubbers, packed towers and bubble-cap columns, are expensive to construct and difficult to operate with viscous solutions, one aspect of the work was developing a compact, agitated, gas-liquid contactor for use with concentrated absorbents. The efficacy of the agitated contactor for absorbing carbon dioxide in diethanolamine increased with increasing solution rate, turbine speed, diethanolamine concentration, and carbon dioxide concentration in feed gas, and with decreasing liquid-gas ratio. It was unaffected by pressure between 200 and 300 p.s.i.g. and little affected by temperature between 115 and 190° F.

Jan 1, 1961

By R. L. Benner

A compound stability diagram was constructed by the Bureau of Mines for the Zn-Fe-S-O system to show the phases that should be thermodynamically stable at various temperatures, oxygen pressures, and SO2 pressures. The diagram was demonstrated to have good qualitative value for predicting stable phases that may, in turn, be related to the recovery of zinc in the leaching phase of the electrolytic zinc process. The study showed that roasting temperature is the most Significant variable in preventing roaster formation of zinc ferrite, which is directly related to subsequent extraction of zinc in the leaching step.

Jan 1, 1966

By W. G. Hopkins

The development of systems for location of miners who have become entrapped following a mine disaster has been one of the major research goals in the Bureau of Mines. This study details the preliminary development of such a system. Current technologies for locating trapped miners from the surface are either simple direction finders or time difference pulse systems that have accuracy limitations. Developing technologies using full vector field measurements at several receiving points are currently being studied. The necessity of measuring field strength with great accuracy can be a drawback in these systems. A system that operates with continuous wave radio signals, whose phase differences can be measured accurately even in weak signal conditions, greatly improves the location accuracy. A microcomputer would be used in conjunction with the system, to gather and manipulate the data to automatically pinpoint the location of the trapped miner. Comparison of this system with existing technology indicates a favorable accuracy/complexity ratio for the phase difference of arrival technique.

Jan 1, 2011

By E. P. Youngman

Gold and precious stones were mined in Egypt in prehistoric times. This mining, carried on at intervals, extended over thousands of years, until about 1300 A. D. Then ensued a dormant period of several hundred yoars. In the mean- time Europe made great rogress in mining practice, metallurgy, and geology and sent out various expeditions during the nineteenth century to investigate ancient mines. But the exploratory work produced no material results, and not until the beginning of the present century did actual mining recommence. The reopening of old gold mines in Rhodesia aroused interest in London and Paris, and these cities provided the capital necessary for the investigation of the ancient minee in West Africa and Egypt. Speculation resulted in the division of most of the uncultivated area of Egypt and the Sudan into huge concessions, and a number of expeditions were made; but after an unprecedented activity in West Africa, roaction set in, and the flow of capital ceased. The concession- aires, mostly individuals with insufficient capital and with a misconception of the initial difficulties of communication, water supply, and labor, allowed

Jan 1, 1932

Multiple-seam interactions are a major ground control hazard in many U.S. underground coal mines. In some U.S. coalfields, particularly in central Appalachia and the West, the majority of today’s mines are operating above and/or beneath previously mined seams. The effects of multiple-seam interactions can include roof falls, rib spalling, and floor heave. These can seriously disrupt mining operations and threaten the safety of miners. In early 2006, a West Virginia coal miner was killed by rib roll that occurred in a high-stress zone beneath a remnant structure in an overlying mine. Fortunately, not every multiple-seam situation results in hazardous conditions. Indeed, the vast majority do not. For the past several years, the National Institute for Occupational Safety and Health has been conducting research to develop better techniques for predicting the location and severity of multiple-seam interactions. During this investigation, more than 50 mines were visited across the U.S. coalfields. Nearly 300 case histories were collected and analyzed using multivariate statistical techniques. The study also employed the numerical model LaM2D to estimate the multiple-seam stress, the Analysis of Longwall Pillar Stability (ALPS) and the Analysis of Retreat Mining Pillar Stability (ARMPS) programs to determine pillar stability factors (SFs), and the Coal Mine Roof Rating to measure roof quality. The study focused on the two most common types of multiple-seam interactions: • Undermining, where stress concentrations caused by previous full extraction in an overlying seam is the main concern; and • Overmining, where previous full extraction in an underlying seam can result in stress concentrations and rock damage from subsidence. The study confirmed that overmining is much more difficult than undermining, and isolated remnant pillars cause more problems than gob-solid boundaries. For the first time, however, it was possible to quantify these effects in terms of the equivalent thickness of interburden needed to compensate for them. The study also found that pillar design is a critical component of multiple-seam mine planning. Many of the failed cases involved pillars whose SF seemed inadequate once the multiple-seam stresses were accounted for. Weaker roof was also found to significantly increase the risk of multiple-seam interactions. The most important result of the study is an equation that predicts the critical thickness of the interburden required to minimize the likelihood of a multiple-seam interaction. This equation was incorporated into a step-by-step methodology that allows mine planners to evaluate each potential interaction and take steps to reduce the risk of ground control failure. Such measures could include installing cable bolts or other supplemental support, increasing the pillar size, or changing the mine layout to avoid the remnant structure entirely. These Proceedings also contain several previously published papers that cover other facets of multiple-seam mining research. Two papers describe the LaModel family of software developed by Professor Keith A. Heasley of West Virginia University. The LaModel programs were designed for calculating the stresses and displacements in coal mines or other thin, tabular seams in layered media. The original three-dimensional version of LaModel is essential for detailed analyses of complex multiple-seam scenarios. LaM2D, by contrast, implements a simplified two-dimensional model that is suitable for quick approximations of the multiple-seam stresses and strains. Three additional papers in these Proceedings describe the extensive multiple-seam experience of the Harris Mine, examples of extreme multiple-seam mining from the central Appalachian coalfields, and longwall mine experiences in Pennsylvania, West Virginia, and Utah. The final paper reports on a numerical modeling study that provided some insight into the mechanics of multiple-seam mining.

Jan 5, 2007

By Oliver C. Ralston, Foster Fraas

The electrostatic separation of solids utilizes the forces exerted when electrically charged particles of the solids are present in an electric field . The charges may be acquired by various means (5) , and when the acquisition or loss of charge depends on the property of the particle , separation can be obtained between particles having different properties . A property commonly utilized in present - day separators in conductance . Charging also may be accomplished by bringing the particles into intimate contact with various surfaces . This is sometimes described as a " frictional electrical effect. The charge , or specifically the polarity of the charge , in this latter case evidently depends on the property known as the contact potential , as has been explained in the discussion of a paper (7) and in several other papers (10) . Separation by this method is accomplished in two steps - a charging step , in which the particles are brought into intimate contact with an electrification surface , and a separation step , in which the charged particles are separated in an intense electric field . Descriptions of such methods may be found in the literature (2) , (7) , ( 8) . Even as early as 1909 , Blake and Morscher (2) described the charging of particles by intimate contact followed by separation in an electric field . They also state that the polarity of the electrical charge acquired by the particles depends on their composition . O'Brien ( 8) presented several designs of apparatus . He obtained electrification by means of a wiping action , either on inclined plates or in rotating cups , in which a centrifugal force was imparted to the particles .

Nov 1, 1942

By E. W. Dean

A previous report of the Bureau of Mines* has supplied data for the physical and chemical properties of samples of crude petroleum produced in the eastern fields of the United States. It was issued as a preliminary chapter of a bulletin which is to cover the results of a survey of the entire country. The present report is a second preliminary chapter including figures that are available for the producing fields of the Rocky Mountain district. Work is being continued. with a series of samples from the States of Kansas and Oklahoma which will be described in a third preliminary chapter, to appear at a subsequent date. Acknowledgments. The obtaining of samples was rendered possible through the courtesy of representatives of a number of producing and refining companies operating in the Rocky Mountain district. The Bureau hereby acknowledges its appreciation of the hearty spirit of cooperation that was universally encountered.

Jan 1, 1921

By Hal D. Peterson

In research sponsored by the Bureau of Mines, a technique was developed for simulation of heap leaching on uranium ores. The equipment used for this simulation consisted of 2-ft-diam columns, constructed in sections, such that ores as coarse as minus 4-in could be treated in bed depths ranging from 8 to 18 ft with test condition variations. The technique consisted of the separate steps of ore preparation, column loading, charge wetting, leaching, washing, and residue recovery. For the ores studied, sulfuric acid was found to be generally superior to alkaline lixiviants. The rate of uranium extraction by acid leaching proved" to be primarily a function of percolation rate, alkalinity of the ores and oxidant requirements of the ores. Column leaching was closely comparable to field-scale heap leaching in terms of uranium extraction rate and recovery results. Acid and oxidant requirements were lower for the field-scale operation. All column tests, as well as the field-scaly heap, achieved in excess of 96-pct uranium extraction on a Bear Creek, Wyoming ore.

Jan 1, 1985

By J. W. Miller

This report deals with upgrading of the coal reserves of Raleigh County, VI. Va., to metallurgical standards. The data on samples herein correctly show the characteristics of the bed at the point where sampled and are used to indicate the general quality of the bed in the county. The principal results and conclusions are: 1. Raleigh County contains large reserves of high-quality, high-, medium-, and low-volatile coals. 2. The principal beds from which an increased amount of coal is expected to be mined in the future are: The Eagle, Powellton, No. 5 Block, Hernshaw, Fire Creek, and Pocahontas No.6.

Jan 1, 1954

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 James W. Townsend

The Vicksburg mining property lies in the southeastern foothills of the Star mining district, Beaver County, Utah (fig. 1). Within a few miles of the Vicksburg mine, lying in a semicircle from south to northwest, are such past producers of lead-silver ores as the Moscow, Hoosier Boy, Red Warrior, Wild. Bill, Harrington-Hickory, and many others. Farther to the north, in the San Francisco district, are the famous Horn Silver and Cactus mines. The formation at the Vicksburg property consists of interbedded limestone, shale, and dolomitic limestone. These beds have been metamorphosed by the intrusion of irregular masses of porphyritic igneous rocks grading from quartz-monzonite to granodiorite. Ore deposition is in north-trending fissures of sheeted zones, contact metamorphic in type. These depositions were subsequently altered to gossan. A preliminary investigation of the Vicksburg property involving surveying, mapping, and sampling was made by W. A. Young and F. H. Gunnell, engineers of the Bureau of Mines, in the fall of 1946. As a result of the investigation, a project was set up to investigate the possibility of ore occurrence at greater depth on the fissures under the mineralized zone by diamond drilling.

Jan 1, 1950

By W. S. Landers

Analysis of the size consist of broken coal has been extended in recent years beyond the mere representation of the relative quantities of the various sizes present in a given lot of the material. Fundamental characteristics of the coal related to the process of breakage fix the distribution of sizes, and it has been found by Rosin and Rammler4/ that a relatively simple law-governs this property. Benhett5/ has described a graphical method of expressing the relationship, and by its use considerable simplification in the expression of size distribution is possible.

Jan 1, 1946

By Mark S. Sanders

The purpose of the present study was to develop and test improved Type V workvests for use on dredge operations. The goal was to design workvests that would be more comfortable to wear, would interfere less with task performance, and would better meet the needs of dredge workers. It was hypothesized that by attaining these goals, the resulting vests would be worn more often and would be kept buckled more of the time than traditional vests. The study involved three major phases. In Phase I, visits were made to dredge operations and a definition of the problem was developed. Problems with current vests were identified and working conditions and tasks surveyed In Phase II, prototype vests were developed and laboratory tests were per-formed to assess comfort and interference. In Phase III, the prototypes were modified and field tested with actual dredge operators and workers.

Jan 1, 1985