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By Paul McIlroy

Costs of producing lead from various known resources in the United States are developed by the Bureau of Mines to define the future availability of domestic lead at various price levels. It is estimated that 60 million tons of primary lead (75 percent of the total resource) is available at $0.20 or less per pound; 72 million tons (90 percent of the total) is available at $0.50 or less per pound; and the 79 mil- lion ton total estimated resource can be obtained at a price or $1.82 or less per pound. The supply available at $0.20 per pound or less will meet demand for over 78 years at the 1970 annual consumption rate of 763,000 tons.

Jan 1, 1974

By R. L. Grayson

"Compliance standards for respirable dust, which are reduced because of high quart: concentrations, have become an industry-wide problem. Research on the physical and chemical character of quart-classified particles in respirable coal mine dusts indicates that they may exist in intermixed layers or may be coated by clay or coal material. The relative amount of intermixing varies with the coal seam being mined. If most of the quart: particles of a mine dust are ""pure,"" then the dust may have a high fibrogenic risk potential because of truly free silica and the compliance standard should be lowered. lf, however, quart: is locked inside another material matrix, or coated, a reduced compliance standard may not be appropriate.Although much research has been done on coal workers' pneumoconiosis (CWP) over the past decades, the etiologic agents of the disease still have not been pinpointed. The predominant methods of characterizing respirable coal mine dusts were bulk analysis techniques for determination of elemental and mineralogical concentrations, the results of which were used in statistical analyses to determine relationships between dust composition and the occurrence of CWP. These methods are incapable of finding the etiologic agents in the dust primarily because of complicated and confounding physiochemical factors, which may be discovered if the focus of characterization was done on a dust particle level.The SEM/EDXA-based research discussed here shows a significant difference in the number of ""pure"" quartz particles in respirable dusts collected from different mines. Some of the results have been reported previously (Grayson, Andre, and Simonyi, 1988). Concurrent research by other investigators (Wallace et al., 1989) demonstrates an SEM/EDXA-based methodology to pinpoint the location of the ""contaminating"" substance(s ) in a quartz-classified particle. The research of the European Economic Community has also begun analyses on the respirable-dust-particle level (Robock and Bauer, 1988).Since the compensatory and intangible costs of CWP are substantial in the United States, it is important that the etiologic agents be determined and then either controlled or neutralized in a cost-effective way. This line of research is especially important consid-ering the forecasted. near-term growth of coal production and the evolution of high productivity longwall panels (an immediate problem in compliance) and continuous mining sections ( a probable future problem).This need has been accentuated now that nearly all respirable dust samples submitted to MSHA are analyzed for free silica (Tomb, Parobeck, and Gem, 1986). Today a real problem exists in the coal industry, both underground and surface, because of high quartz levels in respirable dusts causing substantially reduced compliance standards (Murphy, 1989).The combined results of the respirable dust particle investigators indicate that conventional bulk sample analyses may not faithfully represent the amount of biologically available or active quartz in all mines with a high level (greater than 5% ) of quartz in the dust For example, some mine dusts might contain predominantly occluded (or coated) quartz particles where bulk analysis would result in anomalously high ""free silica"" measurements. The same result would occur when quartz particles are intermixed substantially with other minerals that can alter the surface of the composite particle away from a quartz-behaving character."

Mar 1, 1992

By P. L. Sibrell

Electrorefining of Ti in nonaqueous solvents has been studied by the U.S. Bureau of mines as a method for recycling impure scrap Ti. Electrochemical behavior of Ti species was investigated using cyclic voltammetry. Research results showed that Ti metal can be dissolved in polar solvents such as dimethylformamide or dimethyl sulfoxide. However, deposition of Ti from these solvents was not successful. Several solvent systems were investigated for electrodeposition of Ti but no deposits were obtained. Reduction of Ti4+ complexes to Ti3+ proved to be straightforward, but reduction to lower oxidation states could not be confirmed. In dimethylformamide solutions, cyclic voltammetry results demonstrated the reduction of Ti to an oxidation state of less than three, but no Ti metal was identified. In dimethyl sulfoxide solutions containing LiCl, it was possible to deposit Li metal. After adding Ti salts to the solution, electrolysis quickly passivated the electrode. Deposition of Ti was also investigated in solutions of dimethoxyethane and propylene carbonate but, again, no reduction of Ti to oxidation states of less than three occurred. Therefore, the prospects for a nonaqueous electrorefining system for Ti metal do not appear promising.

Jan 1, 2010

By Lindsay D. Norman

Four chloride and seven fixed-nitrogen processes for recovering manganese from domestic resources are described. The chloride processes are divided into two classes (leaching and chloridization) depending upon the major operation responsible for converting the manganese minerals to the chloride from which manganese oxide products are obtained. The fixed nitrogen processes, all of which yield high-grade manganese oxide products, are essentially either leaching or roasting processes. The 11 processes include HC1 leach, HC1 chloridization, HC1 chloride volatilization, CaC12 chloride volatilization, NO2 leach, HNO3-NO2 leach, NH3-CO2-H2O system leach, (NH4)2SO4 leach, (NH4)2SO4 roast, and ammonium salt roast.

Jan 1, 1963

By Lindsay D. Norman

Four chloride and seven fixed-nitrogen processes for recovering manganese from domestic resources are described. The chloride processes are divided into two classes (leaching and chloridization) depending upon the major operation responsible for converting the manganese minerals to the chloride from which manganese oxide products are obtained. The fixed nitrogen processes, all of which yield high-grade manganese oxide products, are essentially either leaching or roasting processes. The 11 processes include HC1 leach, HC1 chloridization, HC1 chloride volatilization, CaC12 chloride volatilization, NO2 leach, HNO3 leach, HNO3 ?NO2 leach, H3 ?CO2-H2O system leach, (NH4)2SO4 leach, (NH4)2SO4 roast , and ammonium salt roast .

Jan 1, 1963

By M. J. Brnich

The purpose of this U.S. Bureau of Mines study was to assess the ability of trainees to don an unfamiliar self-contained self-rescuer (SCSR) after having become familiar with how to put on a different type of apparatus. Prepractice instruction was the same for all individuals learning to put on a device: a step-by-step, hands-on talk-through using the "3+3" method. Subjects were assigned to groups that had their initial donning instruction delivered on either the Draeger OXY-SR60B or the CSE SR-100. Trainees' performances were then evaluated using the other model. Donning trials were analyzed using a number of measures. It was found that SCSR design had a moderate influence upon how well the donning task transferred.

Jan 1, 2010

By Robert M. Doerr

The oxidation kinetics of Ni-Y alloys in the range 0.04 to 8 weight-percent Y, and of high-purity Ni, were compared by the use of a sensitive volumetric apparatus. The reactions followed approximately the parabolic rate law; for oxidations in 02 at 0.5 atm and 1,200° C, the parabolic rate constant was about 0.37 + (0.064) (Y-2.11) mg cm-2 min-1/2, where Y represents the weight-percent Y in the alloy. Internal oxidation of Y occurred in the alloy specimens and the resultant Y203 particles, which were in patterns related to the eutectic structure of the alloys, served as markers showing that the subsequent oxidation of the surrounding Ni was by inward diffusion of O. The scale consisted in each case of NiO, but the inner parts of the scale on the alloy specimens included the patterned Y203 particles. The thicknesses of the inner parts of the scale depended directly on the Y concentration, and the thicknesses of the Y2O3-free outer parts of the scale were inversely related to the Y content of the alloys. There is thus a relationship between the thickness of the outer part of the scale and the protectivity of the scale. Outward diffusion of Ni and inward movement of 0, from the inner boundary of the Y2O3-free part of the scale, is proposed as a mechanism for these results.

Jan 1, 1966

By J. S. McNabb

"A search for manganese ore by core-drill exploration was carried out by the Bureau of Mines in the Philipsburg mining district in Granite County, Mont., in 1939 and 1940. This work was based on detailed studies of the manganese ore bodies of the district previously made by the Geological Survey.In 1949 further search for manganese in the district was deemed advisable. Diamond drilling was begun the following year as a joint program by the Geological Survey and the Bureau of Mines with the primary purposes of probing ore-leasing structures and extending the limits of known ore bodies. A secondary objective was to test a geologic theory based on a new conception of manganese-ore localization. The exploration targets were designated and the drilling results interpreted by the Geological Survey, and the Bureau of Mines was responsible for the drilling, sampling, and core handling. Improved drilling equipment and methods were utilized in an effort to obtain better core recoveries than resulted from the earlier drilling campaign.The Philipsburg mining district, Granite County, Mont., is 27 miles south of Drurrnnond, about 45 miles airline northwest of Butte, and 1 mile east of Philipsburg. During the course of the investigation patented lode-mining claims owned by the American Machine & Metals, Inc., the Contact Mines, Inc., and the Moorlight Mining Co. were diamond drilled.The district has been an important source of domestic manganese dioxide ore since local recognition of the mineral's importance during World War I. Peak annual output in 1918 of about 127,000 tons of manganese ore was utilized principally by the steel industry. A small but relatively steady output has persisted to the present to satisfy demands by battery manufacturers for battery-grade manganese dioxide.The known manganese deposits of the district are in sedimentary rocks of Paleozoic age. These rocks lie along a north-trending anticline traversed by a series of east-west tension veins. The east flank of the anticline terminates at a steep-dipping fault contact against a small granodiorite batholith.Replacement deposits of manganese oxides and carbonates occur locally in or closely associated with tension veins cutting calcareous rocks, or adjacent to the intrusive. Rhodochrosite has been a common accessory mineral in deposits valuable chiefly for lead, zinc, and silver. Some of the replacement deposits characteristically are irr2gular in outline, whereas others have fairly regular walls marking the limits of favorable beds."

Dec 1, 1955

By Frank J. Wiebelt

Work on the Abbott-quicksilver property was part of the general program of th~ Bureau of Mines in its investigation of domestic mineral resources, which are essential to national defense or industry and of which our present or probable future supplies are inadequate. The mine was discovered in 1862, and the intermittent production up to 1947 has totaled around 37,500 flasks of quicksilver. Output has come from ore shoots formed in the vicinity of fault intersections in a narrow zone composed of lenses of silicified serpentine breccia interbedded with shale. Work by the Bureau included the drilling of six diamond-drill holes aggregating 2,845 feet. Several possible ore zones were intersected by the drill holes. Field work was begun in April 1948 and concluded in October of the same year. This report gives detailed results of the diamond drilling and a brief account of the history and description of the ore deposits.

Jan 1, 1949

By David C. Oyler

Three long horizontal holes were drilled from a directionally drilled surface hole at the Emerald Mine near Waynesburg, Pa. The purpose was to adapt the technique of directional drilling for use in draining methane from coalbeds. A 504-m (1,652-ft) long, 76-mm (3-in) diameter, circular arc pilot hole was drilled, using a downhole mud motor, to enter the Pittsburgh coalbed at a vertical depth of 305 m (1,000 ft). The hole was reamed to 222 mm (8-3/4 in) and was cased to a measured depth of 486 m (1,595 ft). Three 76-mm (3-in) diameter horizontal drainage holes were then drilled, totaling 2,909 m (9,544 ft) of horizontal hole. Improvements in drilling methods increased the average drilling rate from 20.4 ill (67 ft) to 64.9 m (213 ft) per day. The cost of drilling the directional and horizontal holes (using a Government-owned drill rig) was $1,169,530, a figure inflated by inexperience and by delays caused by lost-circulation problems and fishing operations. An estimated total drilling cost of $960,000 (including rental of a drill rig) for an improved system, was determined by a detailed cost analysis. Initial gas and water production from November 1979 through May 1980 was low because of caving of the horizontal holes drilled in shale near the bottom of the casing.

Jan 1, 1982

By William D. Mayercheck, August J. Kwitowski, John R. Bartels

This report discusses the Bureau of Mines' efforts to develop partial protective structures for operators of low-coal shuttle cars. In coal seams 48 in high or less, full-coverage canopies are generally difficult or may be impossible to implement on high-speed face equipment due to the restrictions they impose on the operator's vision and comfort. Lim- ited coverage is one alternative that provides an acceptable level of operator protection in thin-seam applications where conventional full- coverage canopies cannot be used. Three possible limited-coverage de- sign scenarios (roll bars, sliding canopies, and flip-top canopies) were designed, fabricated, and evaluated for low-coal shuttle cars. All three designs were determined to be feasible and desirable for low-coal shuttle car application.

Jan 1, 1987

By T. T. Campbell

Although secondary recovery of lead and lead-tin alloys has been common practice in the United States during recent years, there is little published in-formation concerning recovery techniques. Available information does not cover metal recovery from wet dross skimmings. This investigation by the Bureau of Mines was undertaken to develop techniques that would allow lead-tin alloys to be recovered from wet dross skimmings containing large amounts of zinc chloride. A process was developed, on a laboratory scale, for recovering lead-tin alloys from wet solder dross skimmings. Straight water leaching, either with or without a second leaching operation carried out with a Na2C03 addition for removing chloride, produced a dross that could be smelted without further treatment. Overall recoveries averaging 92 percent of the metal values in the dross were obtained in the form of lead-tin alloys, which had an average tin content of 16 percent and lead content of 84 percent. The recovered alloy contained less than 0.02 percent zinc, as determined by both chemical and spectrographic analyses.

Jan 1, 1956

By K. J. Miller

Electrophoretic mobility measurements of coal and pyrite particles in distilled water revealed a difference between the migration speeds of the two materials toward the anode in a dc electric field. This information led to the development of a laboratory electrophoresis column for separating fine pyrite from coal by utilizing the electrokinetic and the specific gravity differences between coal and pyrite. The study demonstrated on a laboratory scale that pyrite and other impurities can be separated from fine coal by electrophoresis using a stage separation technique. In a cost analysis, electrical power for electrophoresis was extrapolated to about $1 per ton of clean coal product. But, since the only successful tests ever made were in the laboratory with prewashed samples of minus 100-plus 325-mesh coal in distilled water, the cost figure derived is not representative of conditions prevalent in commercial coal cleaning operations. True conditions would reflect costs many times as great. In the course of the work, several scale-up techniques were considered but their feasibility became academic in view of the physical and economic problems associated with electrophoretic separation of pyrite from coal. Although the process and apparatus were finally deemed impractical for commercial coal preparation, the electrophoresis column may have some application as a laboratory device.

Jan 1, 1974

By D. Harrington

The coal-mining industry of the United States finds difficulty not only in making ends meet financially but also in operating with anything like reasonable safety. The record to date has not been particularly good as to either finance or safety, but at least in some phases or safety there are indications of better times to come. During the fiscal year ending June 30, 1929, only 139 lives were lost in explosions in our mines as against 342 lost during the fiscal year ended June 30, 1928; this decrease in such fatalities is definitely a matter for satisfaction. During the fiscal year July 1, 1928, to June 30, 1929, the attention of the safety division of the U. S. Bureau of Mines was directed to 38 mine explosions in the United States. Two explosions were in non-coal mines, one in a semianthracite mine, two in anthracite mines, and 33 in bituminous mines. These were not all major explosions - that is, explosions in which five or more lives were lost; in some of the explosions no lives were lost, while in others fewer than five fatalities resulted. Table 1 gives data on the explosions, showing the number of mines using open or closed lights and the number of explosions with resulting deaths, by causes, for each State.

Jan 1, 1929

By Denise A. Herzog

The U.S. Bureau of Mines conducted a study of cyanide leach technology used in Alaska's mineral industry from 1987 through 1990. Literature and cost data were obtained for mines in the contiguous United States, Canada, and Alaska that use cyanide to recover gold and silver. The data was compiled in an effort to evaluate the economics and conditions associated with cyanide use in Alaska. This report discusses heap leaching methodology and evaluates a "typical" heap leach operation in Nevada and compares the results of the Nevada operation to an analogous hypothetical mine in Interior Alaska. Five daily tonnage rates were analyzed for both the Nevada and the Alaska operations to evaluate the spectrum of economic possibilities. The discounted cash flow rate of return (DCFROR) for each production rate was then evaluated in terms of recoverable metal value (RMV). The Nevada RMV for each production rate was then compared with its Alaskan counterpart, and the results averaged. The Alaskan production costs are an average of 1.71 times greater than costs associated with mining in Nevada at a 0% DCFROR. At 15% DCFROR, costs in Alaska are 2.01 times greater than those in Nevada. Costs are higher in Alaska because of the shorter leaching season, increased labor and transportation costs, and heavier precipitation and vegetation.

Jan 1, 1991

Provide an inexpensive, simple means of supporting highly yielding ground In underground mines. Approach The Bureau of Mines developed a high capacity support post made from standard steel pipe which, when using a 60-inch post configuration, has a 45-ton capacity and a yield length of 24 inches. How It Works The post mechanism is a three-piece unit consisting of a top and bottom leg (made from standard steel pipe) and a separate foot bracket. During installation in the mine, the bottom leg is placed on a relatively flat surface on the mine floor and the top leg is placed over it until its flared end contacts an expansion ring attached to the bottom leg. As the roof and floor converge, the flared end of the top leg is forced into the expansion ring, causing the walls of the top leg to be deformed radially and along the axis. The mechanism will yield until the unit bottoms out after about 24 inches of yield.

Jan 1, 1987

By W. F. Marshall

This Bureau of Mines report discusses tests conducted with four different catalytic reactor designs to determine the influences of exhaust treatment systems on emissions from diesel engines. Although there was significant differences in oxidation efficiencies at light to intermediate engine loads, all four catalysts were very effective in reducing emissions at heavy loads. Compositional determinations included carbon monoxide, carbon dioxide, unburned hydrocarbons, oxides of nitrogen, aldehydes, sulfur dioxide, sulfates, and particulate loading. Particulate size, exhaust odor intensity, and the character of the unburned hydrocarbon component were also determined.

Jan 1, 1978

By Joseph B. Cummings

The Twin Buttes camp embraces eight mines in the Pima mining district. The first mining claims in the camp are said to have been located in 1876, but little mining was done until 1905. Intermittent operation of five of the mi.nes to 1928 yielded 388,231 tons of ore averaging 6.19 percent copper and 8 small tonnage of high-grade oxidized zinc ore. While the Bureau was investigating the area, one mine was active, and it started to produce in 1944. The mines of the Twin Buttes camp are at or near contacts of intrusive granite with Paleozoic limestones and quartzite. The ore shoots lie in metamorphosed sediments adjacent to a zone of garnet rock that separates the ore from the footwall granite. Small fissures that originate at the contact and cut the sedimentaries appear to have been controlling factors in ore deposition. No important ore bodies are exposed at the surface, and those developed wore discovered by sinking on the fissure veins to the contact zone. Most of the area overlying the favorable ore zone is covered by alluvium ranging in thickness from 5 to more than 20 feet.

Jan 1, 1950

By J. E. Chilton

The Bureau of Mines has examined the operation of an oxygen sensor manufactured by the City University, London, England. The sensor produces a current proportional to the oxygen concentration by reacting oxygen at a nonconsumable cathode. The sensor design is unique in that the primary mode of oxygen transport to the cathode is by diffusion through a capillary, The sensor using this design has a stability of 0- to 0.02-pct reading change per day over a 4.7-month test, small temperature coefficient of 0.29-pct reading change per °C, and small pressure coefficient of 0.34-pct reading change per 1,000-ft altitude change, If this sensor were incorporated into an oxygen detector or monitor, this would be a distinct improvement in electrochemical-type oxygen analyzers and would be useful to the mining industry.

Jan 1, 1983

By Larry G. Stolarczyk

This report deals with information regarding a new Medium Frequency (MF) Wireless Communication System for underground mines. This new telecommunication system works on low loss electromagnetic wave propagation modes which allow it to provide quality radio communications almost anywhere in a mine. Tests show the MF system can provide improved safety and managerial control, increased productivity, better organizational team-work and reduced maintenance cost; furthermore, MF's unique design allows for easy installation at a minimum cost. This paper covers the following: 1) MF design plan, 2) Overview of mine radio communications systems, 3) Preparations needed for designing an MF system, 4) MF equipment, 5) MF installation, 6) MF design considerations, 7) MF design specifica¬tions, and 8) Recommendations dealing with MF system. Experiments in four mines are illustrated to demonstrate the success and via¬bility of the MF system. The mines range from small (500 tons/day) to large (67,000 tons/day) capacity and represent several different mining methods. The MF Wireless Communication System represents an advancement in mining communication and the groundwork for other advanced mine systems.

Jan 9, 1984