Search Documents

By Bertrand L. Johnson

Barite, the natural sulfate of barium (BaSO4), is the most important barium mineral. Normally it is white (opaque to translucent), but impurities sometimes render it yellow, gray, blue, brown, red, or black. Brown or red stains are commonly caused by iron oxide. Barite is unusually heavy (specific gravity, about 4.5); in fact, it is one of the heaviest of the nonmetallic minerals. It is brittle and fractures unevenly. The hardness of barite ranges from 2.5 to 3 but is usually about 3. It can be scratched by a copper coin. Pure barite contains 65.7 percent BaO and A.3 percent S03. Much of the crude barite ore mined, however, contains impurities; thus it has a lower content of barite and consequently less barium oxide. Commercial analyses show its total BaSO4 content. Barium also occurs in nature as the mineral witherite (BaCO3), which, however, is not common in the United States, and commercial deposits have been found only in California. Witherite is a yellowish-white, light-gray, or Kite mineral with a specific gravity of about 3, a hardness of 3 to 4, and an uneven to subconchoidal fracture.

Jan 1, 1941

By N. Kumar Kittusamy

Operators of construction equipment perform various duties at work that expose them to a variety of risk factors that may lead to health problems. A few of the health hazards among operators of construction equipment are: (a) whole-body vibration, (b) awkward postural requirements (including static sitting), (c) dust, (d) noise, (e) temperature extremes, and (f) shift work. It has been suggested that operating engineers (OEs) are exposed to two important risk factors for the development of musculoskeletal disorders: whole-body vibration and non-neutral body postures. Method: This review evaluates selected papers that have studied exposure to whole-body vibration and awkward posture among operators of mobile equipment. There have been only few studies that have specifically examined exposure of these risk factors among operators of construction equipment. Thus other studies from related industry and equipment were reviewed as applicable. Conclusion: In order to better understand whole-body vibration and postural stress among OEs, it is recommended that future studies are needed in evaluating these risk factors among OEs.

Jan 1, 2004

By Gene R. Reid

The contract objective is the development of an Automatic Fire Control System for Mobile Underground Metal Mining Equipment. The Phase I Report, which described the projected data handling plan, was published on July 24, 1975. The Phase II effort covered the period from July 24 through December 2 and accomplished the following objectives: ? Acquisition of data in accordance with the project data handling plan. Data were acquired through visits to twenty mine sites in ten states and Canada; visits to Bureau of Mines and MESA facilities; visits to mobile equipment manufacturers; and an extensive literature search. ? Analysis of accumulated data which provided the following specific types of design inputs: selection of the type of mobile underground equipment found to represent the greatest overall fire hazard; typical operating conditions for the vehicle; characteristics of the reported fire experiences; and performance, cost and maintenance factors affecting potential purchases of automatic fire control systems for underground mining equipment. ? Development of the AFCS design concept. Utilizing the data analysis results and considering the state-of-the-art of fire control system components, a recommended design concept was developed with particular emphasis placed on the need for a low cost and reliable system. Design trade-off studies are provided for the recommended system and for four alternate system concepts.

Jan 1, 1975

By E. G. King

The Bureau of Mines made experimental determinations of the heats of formation of forsterite and chrysotile at 298.15° K. The heat capacities of two polymorphs of serpentine, chrysotile and antigorite, were measured over the temperature range from 50° to 298° K and the entropies at 298.15° K were evaluated. The heat content of antigorite above 298.15° K was measured to 850° K. These thermochemical data were combined with other pertinent data to give heat and free energy of formation values at high temperatures. Free energy values are given for the reaction, forsterite + water = brucite + serpentine at different temperatures and pressures.

Jan 1, 1967

By Catharine T. Fogg

The U.S. Bureau of Mines investigated the availability of platinum, palladium, and rhodium from 16 deposits in four market economy countries (MEC's). Major recoverable products include 164 Moz of platinum, 80 Moz of palladium, 13 Moz of rhodium, 24 Moz of ruthenium, 4 Moz of Iridium, 2 Moz of Osmium, and 10 Moz of gold. The 12 deposits in the Republic of South Africa are estimated to account for 96.7 pct of total recoverable platinum. The base-case scenario estimates the long-term cost of production including recovery of capital, but provides no return on the investment or O-pct discounted cash-flow rate of return (DCFROR). The total production costs in January 1990 U.S. dollars ranged from $325/oz to $1,288/oz of platinum compared to an average January 1990 price of $492/oz. Approximately 83 pct of total recoverable platinum was economic at a cost level of $4S0/oz or less. At the IS-pct DCFROR, only 26 pct of total recoverable platinum was economic. For platinum-group metals (PGM), attention has been focused on the ratios of the three primary metals: platinum, palladium, and rhodium. Sensitivity analyses were performed to determine the impact long-term rhodium price increases could have on the total cost of production for platinum and palladium.

Jan 1, 1993

By J. M. Davidson

The potassium mineral polyhalite (K2SO4.MgSO4.2CaSO4.2H2O) found in large deposits in western Texas and southeastern New Mexico is associated with varying amounts of halite (sodium, chloride, NaCl) and anhydrite (calcium sulphate, CaSO4). Although the anhydrite, because of its low solubility and slow rate of solution, is relatively inert, the halite is dissolved immediately in any process solution with which the polyhalite comes in contact. Limited quantities of sodium chloride in the liquors used for the hot extraction of polyhalite materially improve the results obtained, but only a very small sodium chloride content may be desired in the entering polyhalite in other procedures, such as Bureau of Mines process. In all of the processes suggested for the recovery-of potassium sulphate from polyhalite the control of the sodium chloride content will be desirable, if not absolutely essential to efficient operation.

Jan 1, 1934

By M. E. Volin

The tungsten potentialities of the Combination mine were examined by a mining engineer of the Bureau of Mines in 1947. A report based upon his personal knowledge of the mine and the results of the examination contained recommendations for further investigation. This report presents factual data from Bureau of Mines field investigations begun in August 1947 and continued until December 1948, except for a 5-month recess during the first winter. The Combinat.ion mining property of 52 patented claims and 15 patented mill sites is in the Black Pine mining district, Granite County, Mont., 11 miles northwest of Philipsburg. The altitude in the mine vicinity is approximately 6,500 feet.

Jan 1, 1952

By Larry Patts, Jon Hummer, Jim Noll, Aleksandar Bugarski1, George Schnakenberg, Steve Mischler, Mike Crum, Shawn Vanderslice, Rick Anderson

This study is organized under the auspices of the Metal/Nonmetal Diesel Partnership formed by the National Institute of Occupational Safety and Health (NIOSH), the National Mining Association (NMA), the National Stone Sand and Gravel Association (NSSGA), the United Steel Workers of America (USWA) and the MARG Diesel Coalition. The ultimate objective of the study is to reduce the exposure of underground miners to diesel particulate matter (DPM) and gases, and to help in fulfilling the partnership’s goal of identifying technically and economically feasible controls to curtail particulate matter emissions from existing and new diesel powered vehicles in underground metal and nonmetal mines. The majority of current knowledge on the performance of the diesel particulate filter (DPF) systems and other control technologies is based on studies done under laboratory conditions, the results then being applied the results to on-highway vehicles. According to the best knowledge of the authors, only two comprehensive studies that were conducted recently at Noranda’s Bathurst Mining and Smelting Mine and International Nickel Company’s Stobie Mine under the sponsorship of the Diesel Emissions Evaluation Program [McGinn 2001, Bugarski and Schnakenberg 2001, Bugarski and Schnakenberg 2002] offered some insight into the problems associated with the deployment of modern DPFs to underground mining vehicles. The U.S. mining industry has expressed concern that this rather limited knowledge base is not sufficient to help them comply with the rule limiting DPM exposure of underground metal and nonmetal miners [30 CFR 57.5060 2001]. The partnership agreed that a series of comprehensive field evaluations of DPFs in several underground mines was needed to determine their viability of DPF systems and establish confidence in their performance. The first in this series of studies was the one conducted in Stillwater Mining Company’s Nye Mine, Nye, Montana. This study was conducted in two phases. The objective of the first phase was to establish the effectiveness of the selected technologies in reducing diesel emissions by using an isolated zone methodology. The objective of the second phase was to assess the effectiveness of diesel particulate filters in controlling the exposure of underground miners in actual production scenarios. As part of the first phase of the study a series of tests were conducted at Nye Mine from May 19, 2003 until May 30, 2003. The results of Phase I of the study are presented in this report.

Jan 1, 2005

By Richard D. Smith

The Bureau of Mines evaluated the emission control methods, including the capital investments and operating cost, necessary for further reducing lead levels in ambient air at the Glover, Herculaneum, and Buick smelter-refineries in Missouri and the East Helena, MT, smelter. The U.S. Environmental Protection Agency (EPA) has proposed more stringent lead in ambient air standards than those currently in effect. This report presents theoretically achievable lead emission reductions and estimated capital and operating costs. Lead emission inventories theoretically can be reduced from 1985 levels by 2,421 lb/d at the three Missouri operations by containing and filtering fugitive emissions within structural enclosures and baghouses. The aggregated capital and operating costs in 1986 dollars using conventional environmental and workplace technologies are estimated to be $250,014,100 and $18,507,800, respectively. Estimated total incremental cost is $0.063/lb as refined lead. Additional regulatory costs attributable to Occupational Safety and Health Administration (OSKA), U.S. Department of Labor, workplace standards are included since proposed environmental controls may otherwise degrade workplace conditions. Continuous drossing is evaluated as an alternative to conventional OSHA controls. Substituting continuous drossing for conventional work- place technology results in an estimated aggregated capital and operating costs of $258,344,800 and $15,719,600, respectively. Estimated total incremental cost is $0.062/1b as refined lead. For comparison, the average open market price of refined lead during the first quarter of 1986 was $0.184/lb.

Jan 1, 1987

By BUREAU OF MINES

In 1948 the United States became a net importer of oil. Coupled with an unprecedented domestic production of 5,900,000 barrels daily, imports approximating 500,000 barrels made available a total supply of 6,400,000 barrels a day. Thus, by a herculean effort, the oil industry was able to meet an extraordinary demand at home and, in addition, to ship abroad almost 460,000 barrels daily of petroleum and products. The country’s oil position now differs greatly from that prevailing at the beginning of World War II. Then, actual oil production averaged about 4 million barrels a day, and productive capacity probably was greater than 5 million barrels a day. As the demand of the military and industrial machine grew with the rising tempo of the drive toward victory, the United States not only met its own needs but produced about two-thirds of the total oil requirements of the Allied Nations, excluding Russia. As a people, we can be deeply grateful that the Nation’s petroleum resources were adequate and sufficiently developed to support such a tremendous effort. Even in those critical hours when immediate needs were the paramount issues, a prudent Congress paused to contemplate the importance of an assured long-term supply of liquid fuels. From these deliberations came the Synthetic Liquid Fuels Act of 1944, which authorized research and development work on new sources of oil – coal, oil shale, and agricultural and forestry products. Since World War II, a civilian demand for 6 million barrels of petroleum products has become the order of the day. By drilling as many as 39,000 new wells a year, the production rate has increased enough to meet domestic requirements by a bare margin. Some imports were necessary, however, to fill both domestic and foreign demands, and these doubtless will increase. Is this policy of exploration within the United States and the development of oil in foreign countries adequate insurance for the fulfillment of our future national needs? This question has two aspects – one purely civilian and economic in character and the other significant from the standpoint of our national defense. There are now approximately 4,000 producing oil fields in this country. At first thought, it would appear that production could decline in a considerable number of these fields without materially affecting the overall daily output. However, 48 percent of the oil comes from only 111 major fields which contain 60 percent of the total proved domestic reserves. It is apparent, then, that the flow from large fields – having proved reserves of 100 million barrels or more each – must be sustained if daily production is to be kept at the present levels. Essentially, this means that new major fields must be discovered about as rapidly, or perhaps more rapidly, than the older ones lose productive capacity. From 1940 through 1947, only eight major fields with estimated reserves of more than 100 million barrels each were discovered and proved – an average of one such field a year. The total estimated reserve of these eight fields was less than 1 year’s supply at the present rate of use. As drilling continues, some existing fields ultimately will prove reserves larger than those now known. Without a pronounced increase in the number of major discoveries, however, the prospects for increasing our present productive level are not encouraging. Any gap that appears between domestic productive capacity and demand could be filled with supplies from proved oil resources abroad. Assuming cheap pipeline and tanker transportation to the United States, freedom from exorbitant taxes and charges...

Jan 1, 1949

By P. R. Perry

This publication is a compilation of tested methods for the analyses of titanium tetrachloride, titanium sponge, and various intermediate materials and products. They are presented in concise form without the detail usually found in publication of new methods because many of them are modifications of well known procedures. The Electrometallurgical Experiment Station, Boulder City, Nev., has been developing titanium production methods since 1945. Most of this development was on a modified Kroll Process but also included work on sodium reduction and electrolytic methods. During these years a large variety of samples were analyzed. Most of the analytical problems were solved using published methods or modifications of the same. At the start, there were no published procedures for analyzing titanium sponge using spectrochemical methods. A great deal of study was given to testing several of the well known techniques, and some of them, such as direct sparking of the metal, proved to be completely unsatisfactory. Solution-spark techniques were finally tried, and satisfactory procedures were developed for some of the more common impurities. These spectrochemical methods were then put into routine use for several months before their publication.2/ Some new modifications have been made, and techniques have been developed to determine other impurities found in titanium sponge and tetrachloride. All spectrochemical methods used in 1954 are included in this publication.

Jan 1, 1955

By L. H. Banning

Recent dry-top electric smelting tests at the Northwest Electrodevelopment Experiment Station, Albany, Oreg., indicate that a high-titanium slag and a good grade of pig iron can be produced from alluvial Idaho ilmenite. A total of 120 tons of concentrates were smelted during this investigation, to yield an average of 0.5 ton of slag and 0.3 ton of pig iron per ton of ilmenite. Power consumption averaged 1,400 kv.-hr. per ton of ilmenite, at a feed rate of 400 to 500 pounds per hour, when operating at an electrical energy input of 290 to 370 kilowatts. The optimum operating voltage appeared to be 110 volts, phase-to-phase. Graphite electrode consumption averaged 15.6 pounds per ton of ilmenite smelted. Magnesite furnace refractory withstood the corrosive action of the hot metal and slag better than carbon refractory.

Jan 1, 1955

By D. J. MacDonald

The Bureau of Mines has conducted bench-scale investigations leading to the design of an integrated process for producing reactor-grade zir-conium oxide (Zr02) from zircon sand, which avoids the air pollution, water pollution, fire hazard, and odor problems associated with the hexone-thiocyanate process. The integrated process consists of three steps: production of crude zirconyl sulfate solution, solvent extraction, and production of Zr02 from strip liquor. This report describes the solvent extraction step. Multistage, countercurrent liquid-liquid extraction with a tertiary amine in kerosine was used to separate zirconium from a dilute H2S04 solution containing hafnium and other impurities. Process steps de-scribed include extraction from an aqueous feed solution to form a hafnium-contaminated, zirconium-bearing organic-phase solution, scrubbing to separate zirconium from coextracted hafnium, stripping to transfer hafnium-free zirconium into an aqueous strip liquor, chloride-loading to produce a chloride-bearing organic solution, scrubbing with the chloride-loaded organic solution to remove traces of uranium impur-ity from the zirconium-bearing strip liquor, and regeneration to pre-pare the organic solution for reuse. These steps were performed simul-taneously in steady-state, bench-scale experiments. Zirconium recovery of up to 93 pct was achieved. Results of an economic evaluation are included.

Jan 1, 1984

By Forrest T. Moyer

Need for lightweight building materials was created in the latter part of the nineteenth century by a radical change in building design in which dead load or structural weight was transferred from thick, heavy, load- bearing walls of former construction practice to a load-carrying framework of beams and columns with thin walls. This new design was brought about by the introduction of structural steel followed by reinforced concrete and structural concrete as materials for the erection of the load-supporting frame. The new materials and method of construction made possible the erection of skyscrapers and the building of bridges with long spans, and made feasible additions of one or more floors to existing buildings. As size and design of the load-bearing framework are controlled chiefly by dead load, the natural result was a. search for and use of light- weight materials in partitions, floors, and exterior walls. However, these thin walls created problems of heat and sound. insulation, so that building materials which possessed good heat- and sound-insulating properties in addition to light weight were objects of extensive research. One group of materials developed to fill this need comprised lightweight concretes, of which some were obtained by the use of lightweight aggregates. Although the advantages of lightweight.materials were evident from the first skyscrapers, there was a transition.stage.between the old bearing- wall and modern skeleton-frame types of building, with the heavy and massive construction of the former superimposed upon the latter. Hence, it was not until the period between 1910 and 1930 that the new lightweight concretes were recognized and used more extensively in the erection of large, nonresidential buildings. From this type of construction, light- weight-aggregate concretes entered-fields of residential and small non- residential building; in which they were found desirable for production of prefabricated, large-size; masonry units. Although the weight of each unit was reduced sufficiently to enable one man to handle it easily, properties of the new concretes other than light weight were the principal factors in the ready acceptance of these new materials in residential building. Manufacture of precast units includes complete lines of masonry and back-up blocks, bricks; floor beams, columns and partition, roof, and floor tiles and slabs. Recent improvements in casting machinery, development of the vibration-pressure machine, and a more thorough study and knowledge of the requirements and properties of the concrete mix have all contributed materially to the rapid expansion in use of lightweight aggregates in this industry.

Jan 1, 1942

By William O. Vanderburg

This report3/ gives the results of a reconnaissance of mining districts in Eureka County, Nevada, made from September 25 to October 20 and from October 27 to November 5, 1577. During this time, virtually all the districts were visited and many data obtained on active and inactive properties. This report covers the locations of the various districts, geological background, ownership and brief descriptions of mines and prospects, information on past and current operations, and, other data likely to be useful to those interested in the development of our mineral resources. From the viewpoint of past production in the county, the silver-lead-gold deposits at Eureka have been tie most important, followed by the silver deposits at Cortez and Mineral Hill. The period of greatest activity in the foregoing districts was from 1870 to 1990, when Eureka was one of the principal mining areas in Nevada; the production of lead was sufficient to affect its price in all the commercial centers of the world. Eureka also merits the distinction of being the birthplace of the silver-lead smelting industry in the United States.

Jan 1, 1938

By M. J. Waller

Surface resistivity techniques were used at four field sites to monitor changes in apparent resistivities with variations in soil moisture content in the vadose zone. Apparent resistivity values were correlated with gravimetric moisture contents from soil samples taken at each site. Tensiometer readings were taken at two sites and correlated with the results of gravimetric moisture contents and apparent resistivities. Moisture at two of the sites was added by extensive watering; rainfall events were monitored at the other two sites. A recharge event at a dewatering program was monitored at a fifth site. A Ghosh-Koefed multi-layer computing algorithm was used to derive true resistivities from bulk or apparent resistivities. An automated data acquisition system was developed to measure resistivity changes and to process the data in the field. These studies are the first to evaluate measurement of moisture migration in clay rich soils using surface resistivity techniques. Results indicate that surface resistivity techniques readily measure changes in moisture contents in the vadose zone in clay rich soils. Correlation of apparent and true resistivity values with gravimetric moisture contents is more complex and requires additional research.

Jan 1, 1986

By Dennis R. Dolinar, Christopher Mark, Gregory M. Molinda

Despite more than half a century of experience with roof bolting, no design method has received wide acceptance. To begin to improve this situation, National Institute for Occupational Safety and Health (NIOSH) conducted a statistical study of roof bolt performance at a number of mines throughout the U.S. Case histories were collected from 37 mines with a variety of roof bolt types and patterns in a wide range of geologic environments. Performance was measured in terms of the number of roof falls that occurred per10,000 ft of drivage. The study found that roof falls are rare when the roof is strong and the stress is low, even with light roof bolting patterns. The focus of this paper is on the more difficult conditions, where the roof is weaker and/or the stress is higher. Analysis of the results led to guidelines that can be used to make preliminary estimates of the required bolt length, capacity, and pattern. The guidelines are based on the depth of cover (which correlates with stress) and the roof quality (measured by the Coal Mine Roof Rating (CMRR), and the intersection span. Another contribution is a formula for estimating the horizontal stress level in the eastern U.S. coalfields as a function of the depth of cover. The design guidelines are currently being implemented into a computer program called Analysis of Roof Bolt Systems (ARBS).

By E. P. Youngman

This digest, based upon a translation" of certain portions of the 1930 law, covers the pertinent points of what has been termed "The New Mining Law of Luxemburg," the Grand Ducal Order (Arrêté) of April 26, 1930, concerning the exploitation of "mines, minières, and carrières, 4 and abrogating the order of January 2, 1891, concerning the same subject." The Duchy of Luxemburg, which between 1735 and 1815 was French, adopted as its basic mining law the French Law of April 21, 1810, and an Imperial Decree of January 3, 1813. The Luxemburg Government later supplemented and modified this legislation by the laws of June 12, 1874, April 30, 1890, and May 10, 1898, which, with article 36 of the Constitution, are to be taken into consideration in a complete survey of mining legislation. The order of

Apr 1, 1933

The coal-bearing strata of Oklahoma occur in the eastern part of the state over an area of 14,500 square miles, 20.7 percent of the state's total area. Commercially valuable deposits of bituminous coal cover about 8,000 square miles in seams ranging from ten inches to five feet thick. Estimated reserves in Oklahoma are 1.6 billion tons, representing 0.3 percent of U.S. coal reserves. The vast majority of coal mined in Oklahoma used in a single power plant within the state. Oklahoma gained primacy when its regulatory program was conditionally approved January 19, 1981. Authority for the state to administer the Abandoned Mine Land program was granted January21,1982. On April 30,1984, the Office of Surface Mining substituted direct federal enforcement of the inspection and enforcement portions of the Oklahoma program. This substituted enforcement was based upon a finding by OSM that Oklahoma had not operated the inspection and enforcement portions of its program effectively. As of January 1, 1986, Oklahoma inspection and enforcement authority was reinstated. Full program authority was granted to Oklahoma on January 14, 1986.

Jan 1, 1992

By Arne Landsberg

The Bureau of Mines measured the vapor pressure of FeC12 , FeBr2, FeI2, Sb, Bi, Cd, Mg, Pb, FeC13 , and VCl2 using the Knudsen-and torsion-effusion methods, and on FeC13 -NaC1 mixtures, Au2Cl6, and MgNi2 using only the Knudsen method. Apparent vapor pressures calculated from the experimental data vary with orifice size and method of determination. Reaction with residual oxygen in the instruments was noted to have an effect on the iron halide data. Vapor pressure curves plotted as log P versus 1/T (where P is pressure and T is absolute temperature) for one substance using several orifice sizes tended to converge at a single point when extrapolated beyond the experimental region. All of the data, except those of VC12, agree with previously published results. The importance of comparing effusion measurements with those obtained by other methods and the variations encountered with various orifice sizes are discussed.

Jan 1, 1977