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By Donald F. Reed

In the Coastal Plain sedimentaries of northeastern Mississippi, high-alumina clays and kaolins, which are bauxitized locally to varying degrees, are found in many places along the contact between the Midway (Paleocene) and the Wilcox (Eocene) series. The trace of the contact extends from Tippah County, on the Tennessee border, south to Winston County, thence southeast to Lauderdale County, and into Alabama. Its length within Mississippi, disregarding sinuosities, is 185 miles (fig. 1). Commercial production of bauxite from the region has amounted to about 400 tons, shipped from one outcrop in Komper County. In December 1941 and January 1942, the Bureau of Mines and the Federal Geological Survey made a reconnaissance survey of the contact zone and selected the most promising areas for further study. In 1942, four areas in Benton, Union, and Pontotoc Counties were investigated by auger and rotary core drilling, and in 194, core drilling was done on five areas in Kemper, Noxubee, and Winston Counties. The present report records the work done by the. Bureau of Mines and the factual data obtained from the investigations of the nine areas in the two projects.

Jan 1, 1952

By Wils L. Cooley

Although electric utility companies have been active in grounding and bonding within substations, the mining engineer or mine electrical engineer is not involved to the extent that he can be fully up-to-date on the most effective practices for substation construction. The coal mine power system is grounded in a fundamentally different way from most other industrial power systems and is subject to considerable Federal and State regulation. At this time, there is little information that is directly applicable to the mine situation, especially if the substation must be built in an area of limited size or in low-conductivity earth. The objective of this guide is to provide specific engineering information to the mining; industry. Using as little theory as possible, it was written to be general enough to cover most substations, but specific enough to provide direct help with each substation. It will attempt to recommend practice that is in agreement with present Federal rules and regulations.

Jan 1, 1980

Rock mass classification is widely used throughout the underground mining industry—in both coal and hard-rock mines. It is used in all stages of the mining process, from site characterization to production operations. The goal of the International Workshop on Rock Mass Classification in Underground Mining was to provide a forum for leading practitioners of rock mass classification to come together and share their methods and experiences with the technique. The workshop was held in Vancouver, British Columbia, Canada, on May 31, 2007. It was co-chaired by Christopher Mark, Ph.D., P.E., National Institute for Occupational Safety and Health, Pittsburgh, PA, and Rimas Pakalnis, P.Eng., University of British Columbia, Vancouver, Canada. The proceedings of the workshop contain 16 invited papers from 9 countries, reflecting the international depth and breadth of current practice. Applications in both hard-rock and coal mining are well represented. Some of the topics that were addressed at the workshop include: • Major rock mass classification systems used in mining and their variants • Collection of input data through observation, rock testing, and geophysics • Design of mine layouts and rock support systems using classification • Estimation of rock mass strength and other input parameters for numerical models from classification • Applications in weak rock, raise boring, cavability assessment, and other special topics • Risk assessment using rock mass classification

Jan 5, 2007

By J. J. Forbes

Investigations by the Bureau of Mines and by mining-research departments of European countries have established definitely the value of rock-dusting to prevent or limit the propagation of coal-mine explosions. Its effectiveness in this connection has been demonstrated not only by research but by actual coal-mine explosions in which hundreds of lives have been saved because of its presence. In a general way this paper gives pertinent facts concerning rock-dusting practices in the United States. Information has been obtained from many reliable sources, and various coal-mining companies have furnished data on cost and other details.

Jan 1, 1939

By Galen H. Clevenger, MARTINUS H. CARON

Although there are exceptions, oxidized silver ores containing the higher oxides of manganese are generally refractory to hydrometallurgical methods of treatment. When these ores are of high enough grade they can be smelted; indeed, some rather low-grade ores of this type have been smelted at a profit because of their fluxing value. In the past, when these ores could not be smelted, they either were not treated or were treated at low efficiency, generally by cyanidation. The need for thorough investigation of the problem was therefore evident for some time before the writers began their research. The problem of treating manganese-silver ores seems to have been recognized first about 35 years ago by C. W. Goodale in applying pan amalgamation at Tombstone, Ariz. He attributed the low extraction of silver to the fouling of the mercury by manganese rather than to the presence of a refractory compound of manganese and·silver. Although definite knowledge as to the cause of the poor extraction of silver was lacking, a more or less effective preliminary treatment, that is, a chloridizing roast, was applied. E. M. Hamilton, in 1909, was perhaps the first to define clearly the problem as it affects the cyanidation of silver ores and to suggest possible methods of preliminary treatment. Most of the work done in the interval between the appearance of Hamilton's paper and the assumption of the investigation by the authors was in the nature of routine tests covering suggestions already made rather than of research directed to a fundamental study of the problem. No practical application has so far been made of any of these proposed processes. The investigation described in this bulletin has proved that there s a refractory compound of manganese and silver-probably a manganite- insoluble in cyanide solution and other common solvents for silver. Although this compound has not been isolated from natural ores, it has been made synthetically, and shows all the characteristics of the natural product. Furthermore the authors have shown definitely that heating in air a relatively small amount of a silver compound with a large excess of silica (in the proportions ordinarily occurring in a commercial silver ore) renders

Jan 1, 1925

By S. B. Bealko

Mining haul trucks comprise the majority of the equipment used in underground limestone mining operations and are known to emit high levels of noise. A previous study conducted by the National Institute for Occupational Safety and Health (NIOSH) indicates that 70-90 percent of all miners have a noise-induced hearing loss (NIHL) great enough to be classified as a hearing disability by retirement age. These results demonstrate the public health need to protect the hearing of workers in the mining industry, including haul truck drivers. Cab enclosures present an opportunity to isolate the haul truck operator from both truck and other noise in the mining environment. A total of twenty-five haul truck cabs were studied which were divided into three style (treatment) categories determined by soundproofing features and technology for noise reduction: old-, new-, and retrofitted-style. This study examines the contribution of cab acoustics, operator performance, and maintenance to noise reduction for each cab style. Dosimeters were used to measure 8-hr time weighted average sound pressure levels (TWA8 SPLs) inside and outside the cabs to determine if different acoustical treatments affect cab attenuation. Adherence to the Mine Safety and Health Administration (MSHA) Permissible Exposure Limit (PEL) of 90 dB TWA8 (with a 90 dB threshold) was used as the main indicator of overall noise reduction achieved. Dosimetery results indicate only 2% of the samples exceeded the PEL, but samples could still be reduced much further. Descriptive and comparative statistics indicate that noise levels inside the new-style cabs are significantly lower than the other two cab styles. Also, data suggest that there is no difference in noise exposures when comparing the old-style to retrofitted cab styles. Operator influence (opening doors and windows) was a significant factor for increasing noise exposure. This paper demonstrates that properly designed cabs can achieve major noise reductions, but noise levels could still be reduced much further below the MSHA PEL. New-style cabs, equipped with modern noise-reduction treatments, exhibit much lower noise exposures than the other two cabs styles, and the effectiveness of the current noise-reduction treatments for retrofitted cabs is questionable. Haul truck driver observations indicate that improved noise exposure reduction training is needed. Finally, specific targets for future noise reduction research are suggested that will further contribute to the prevention of hearing loss for haul truck operators.

By J. J. Forbes

Investigations by the Bureau of Mines and by mining-research departments of European countries have established definitely the value of rock-dusting to prevent or limit the propagation of coal-mine explosions. Its effectiveness in this connection has been demonstrated not only by research but by actual coal-mine explosions in which hundreds of lives have been saved because of its presence. In a general way this paper gives pertinent facts concerning rock dusting practices in the United States. Information has been obtained from many reliable sources, and various coal-mining companies have furnished data on cost and other details.

Jan 1, 1939

By T. L. Joseph

"IntroductionThe efficiency of ore reduction in the blast furnace and fuel requirements depend upon the degree of uniformity with which reducing gases can be distributed through the stock column and upon the permeability of individual pieces of ore and sinter. If the ore is fine, the major problem in reduction is to get the ascending gas stream to the surface of the ore-Hard, dense ores of low permeability, mined in coarse sizes, tend to improve the permeability of the bed, but unless they are crushed to the proper size they reach the hearth unreduced.Surveys by the Bureau of Mines have shown conclusively that the gas distribution in the upper three fourths of the furnace is far from ideal. Furnace lines, top design, and methods of charging are important, but more thorough size preparation of the ore is necessary to eliminate size segregation at the stock line, which inevitably leads to non-uniformities in gas distribution.Because of the quantity of sinter now produced close study of the characteristics which determine its behavior in smelting is warranted. As the use of concentrates increases agglomeration will become more of a necessity. Improvements in the physical character of the ore burden are particularly important to plants using coke of poor physical quality. In addition to aiding reduction, improved physical properties of the ore burden will permit the use of higher blast heats, which is equally important.Reduction Tests on Fine Sizes of SinterPrevious reduction tests on minus 0.742— plus 0.525--inch pieces of commercial sinters revealed large differences in porosity and reducibility. The results have been published in a former report. 3 Although the physical properties of the sinter, particularly porosity, were found to be of major importance in determining the rate of deoxidization, it appeared that certain chemical properties of the sinter appreciably retarded the reduction of sinters high in silica. This was attributed to the presence of fayalite, which has been identified by Schwartz and by Luyken and Kraeber4 as an important constituent of sinter. Although furnace operators and metallurgists have assumed that iron silicate is more difficult to reduce than hematite or magnetite, definite data on the reduction characteristics of this material were not available. Tests were undertaken, therefore, to develop a method for de-termining the amount of iron silicate present in sinters so that its effect upon reduction could be observed."

Jun 1, 1934

By D. J. Dollhopf

The objective of this five year study was to investigate the means of establishing non-polluted ground-water and root zone systems in areas where surface mining intercepts physiochemically unsuitable overburden materials. Overburden may need to be sampled on a 60 m grid in order to delineate materials unsuitable for reclamation and to accurately implement selective handling operations. Unsuitable overburden materials were buried successfully in a dragline operation with a minimum of delays, but costs were increased 12 to 53%. After three years the buried material remains above the reestablished aquifer and below the root zone. Construction of a clay cap over the buried material may not be required in semiarid environments. It was shown that some unsuitable overburden materials do not have to be special handled. When inhibitory material constituted <5% of the total overburden volume, such material was essentially not detectable in the resultant spoil pile due to mixing/dilution processes. When inhibitory material exceeded 15% of the overburden volume it was always found in the resultant spoil pile, generally with a smaller extent, indicating partial dilution. At least a portion of the postmine aquifer had hydraulic conductivity rates lower than the premine system, indicating the reestablished aquifer may, in part, conduct ground water very slowly. Postmine ground-water chemical quality in spoil materials had poorer quality compared to premine ground water.

Jan 1, 1981

Illumination hardware developed in conjunction with previous Contracts H024202l, H0242049, and H0242023 had not been adequately tested in actual underground work situations. The purpose of this contract was to install and monitor this equipment on mining machines and in actual working places of coal mines to gain experience with the use of the lamps and support equipment in the abusive and critical environments for which they were intended. The equipment that was to be tested consisted of the following: a. Lamps -A variety of sizes of permissible fluorescent lamps which operate from 12 volts DC power. These include the following sizes: Model 8, (9 watts) 2" diameter; Model 15/2 (14 watts) 2" diameter; Model 15/3 (21 watts) 3" diameter; Model 20 (25 watts) 3" diameter; Model 30, (28 watts) 3" diameter; and Model 40, (39 watts) 311 diameter. Representative photographs of these lamps are shown in Figure 1-1 and 1-2.

Jan 1, 1976

By G. L. Oldright

The data presented in this paper were collected at the smelter of the Consolidated Mining & Smelting Co. of Canada, Ltd., Trail (Tadanac), British Columbia. Many thanks are due to S. G. Blaylock, vice president and general manager, James Buchanan, smelter superintendent, and George Murray, assistant smelter superintendent, for their broad general policy in permitting these data to be taken and published. life are also grateful for the help given by the staff members stated in Paper XI, Report of Investigations Acknowledgment is given several excerpts from experiments by F. E. Lee, head of the research staff. INTRODUCTION The past reputation of zinc as an ingredient in lead blast furnace slags has been bad. Zinc is thought of as a cause of accretions in the shaft of the blast furnace, of hot tops, of the formation of "zinc mush" in the crucible and forehearth, of lead-rich slags, of viscous slags, and. of low capacity in smelting.

Jan 1, 1934

By Roy C. Bartholomae

This Bureau of Mines report presents the results of a laboratory investigation of coal cutting mechanics and noise. These experiments were performed using linear cutting apparatus that operates over a broad cutting speed range. The influence of several coal cutting parameters on the noise, force, productivity, and specific energy associated with linear cuts was ascertained. Some basic theoretical aspects of coal cutting mechanics and noise generation are discussed, and the results of the laboratory experiments are used to formulate analytical models of the coal cutting forces and noise. The analytical model for coal cutting noise is then generalized to account for the more important effects of rotary cutting. Based on the generalized model, an estimate of the sound pressure level at an operator&apos;s position is made for a typical continuous mining machine. It is concluded that by employing linear rather than rotary cuts, using deeper depths of cut, slower cutting speeds, and more efficient cutting tools, it is possible to reduce the level of coal cutting noise, as well as provide benefits to other important areas of health and safety in underground mining.

Jan 1, 1983

By T. A. Klinefelter

ONE OF THE many services rendered by the Federal Bureau of Mines is the identification and general examination of ore and mineral samples. Many of these, coming from almost every State in the Union, are clay and shale samples. Other Government agencies, State geologists, universities, and other laboratories are often requested to make similar examinations. This publication describes methods of testing these samples. An earlier paper, published in 1943, described Bureau of Mines methods of testing such clays.3 This paper was to be followed later with another (part II) that would describe much more thorough testing than did the rather general outline of part I. Part I has been out of print for some time and needs revision, and part II was never written; hence, the present publication is designed to include part I and also those additions intended as part II. The tests presented in part I were simple, requiring only the ordinary equipment to be found in any good chemical laboratory. The second publication was to include a greater number of test procedures and information on increasing the accuracy and precision of those previously given.

Jan 1, 1957

By G. A. Smyres

A GaC12--B2 l-eachtng procedure and meEal-recovery method for treating an arsenical Cu-Co sulfide concentrate was developed by the Bureau of Mines as an alternative to smelting, which is no longer considered an environmentally acceptable method for treating arsenic-containing ores. The procedure involved leaching in a CaC12 solution with CaC03 for 96 h at 26 pct solids (concentrate and CaC03), 1150 C, and a pressure of 50 psig (345 kPa) with oxygen. More than 98 pct of the cobalt and 97 pct of the copper were extracted, and 99.98 pct of the arsenic and 99.9 pct of the iron remained in the leached residue. A filtration rate of 2.9 gal/(ft2.h) [118 L/(m2.h)] and a cake formation rate of 36 Ib/(ft2.h) [172 kg/(m2.h)] were obtained by filtering reacted pulp at 1000 C. More than 99 pct of the copper in the pregnant solution was extracted as CuCl2 by golvent extraction with a new copper extractant. Copper was stripped from the loaded organic with a sulfate-chloride solution, which was used as the anolyte for electrowinning of copper in a membrane cell. Copper plate produced was more than 99.99 pct pure and requi.red 0.81 (kW&apos;h)/lb Cu [1.78 (kW·h)/kg Cu]. Cobalt sulfide was precipitated at pH 3 with Ca(HS)2.

Jan 1, 1986

By James A. Brierley

Wastewater from uranium mines in the Ambrosia Lake district near. Grants, New Mexico, U.S.A., contains uranium, selenium, radium, and molybdenum. The Kerr-McGee Corporation has a novel treatment process for waters from two mines, sections 35 and 36, to reduce the concentrations of the trace contaminants. Particulates are settled by ponding, and the waters are passed through an ion exchange resin to remove uranium; barium chloride is added to precipitate sulfate and radium from the mine waters. The mine waters are subsequently passed through three consecutive algae ponds prior to discharge. Water, sediment and biological samples were collected over a 4-year period and analyzed to assess the role of biological agents in removal of inorganic trace contaminants from the mine waters.

Jan 1, 1981

By Ivette E. Torres

Aruba, formerly a. part of the Netherlands Antilles, separated on January I, 1986, and became an autonomous part of the Netherlands. Full independence of the island from the Netherlands is scheduled for 1996. In this chapter, however, Aruba&apos;s statistics are included with those of the Netherlands Antilles. Tourism continued to be the main industry of the island, which continued to depend heavily on imports, mostly from the United States. During the year, the Government was preparing legislation to regulate the exploration of oil deposits in the relatively shallow sea around Aruba.

Jan 1, 1989

By George A. Morgan

The production and processing of crude petroleum and natural gas are the dominant economic sectors of the Middle East. Downstream processing of these mineral fuels to petrochemicals and fertilizers is a major investment opportunity. In 1991, the 15 countries that constituted the region accounted for 26 % of world crude petroleum output, 15.3 % of world natural gas plant liquid production, and 4.5 % of world dry natural gas production. Only Cyprus and Lebanon were not crude petroleum producers. Production of these mineral fuels all declined from that of 1990 owing to the Persian Gulf War, during which output from Kuwait and Iraq either ceased owing to war damage, or was embargoed. Prior to the war, Iraq and Kuwait were the fourth and fifth largest world producers of crude petroleum, respectively. In the war, virtually all of Kuwait&apos;s production and transport facilities were destroyed or damaged. Iraq&apos;s output was embargoed from export, with only domestic sales taking place. The embargo also affected Jordan, both in terms of transshipment of materials through it to Iraq and in exports of phosphate and potash. Shipments of crude petroleum by pipeline from Iraq through Saudi Arabia and Turkey and by vessel through the Persian Gulf were terminated. However, the loss in production from Iraq and Kuwait was made up by accelerated output from other Middle East and world producers. Saudi Arabia, in particular, with its excess production capacity, accounted for the largest portion, increasing crude petroleum output by 27 % to almost 3 billion barrels.

Jan 1, 1993

By Nathan T. Lowe

This report updates an accounting of mines and prospects in the Seafoam mining district, Custer County, Idaho, begun during mineral appraisal of the Idaho Primitive Area. Thirty-two mine and prospect locations have been added to the Bureau&apos;s Mineral Industry Location Subsystem (MILS) data base as a result of initial phases of mineral appraisal of the River of No Return Wilderness; most previously known locations were field checked and the updated information added to the data base. The district&apos;s major deposits include polymetallic fissure veins of gold-silver-lead-zinc-copper hosted by granodiorite and quartz monzonite which have been intruded by dikes ranging in composition from rhyolite to dacite, and vein type replacements of silver-lead-zinc-copper hosted by calcareous xenoliths imbedded in major intrusives. These deposits may be related to the intrusion of the Rapid River pluton or the Casto pluton. The dominant northwest structural trend is parallel to an aeromagnetic high, a weak gravity salient, and the Blue Bunch Mountain dike swarm.

Jan 1, 1983

By G. W. Jones

In a previous report,6 results were given that showed the amount of natural ventilation in a manhole having a capacity of 74.l cubic feet when the number of ventilation openings in the cover was varied. from no openings to a maximum of 48. The results showed that the ventilation (air changes per day) in the manhole was proportional to the area of the openings in the cover, and also that the number or area of the openings was the factor that chiefly affected the ventilation.

Jan 1, 1937

By Oliver Bowles

The National Granite Commission at its annual meeting in Norfolk, Va., in January, 1930, passed a resolution requesting the Bureau of Mines to conduct an economic study of the granite industry. In with this request a preliminary review has been made of trends in the production and uses of block granite.. Some unfavorable conditions were thus brought to light, and certain suggestions regarding a more orderly and consistent growth in the industry are herein discussed. The results of the study are, presented in this report for the earnest consideration of. the industry, and comments are invited, not only on this report but as to future work that might be accomplished by the Bureau of Mines. The authors desire to acknowledge many helpful suggestions and comments from Paul M. Tyler of the Bureau of Mines and from Harris F. Sherman, secretary of the National Building Granite Quarries Association. Miss A. T. Coons of the Bureau of Mines rendered valuable assistance through her wide knowledge of granite statistics. The block granite industry has shown little expansion during recent years. While the value of the annual production has grown from about $14,000,000 in 1904 to nearly $25,000,000 in 1928, the increment in value is caused mainly by mounting prices rather than by increased production. Even granite for memorials shows a very small advance in production volume, although the value has increased from about $3,500,060 in 1904 to more than $11,000,000 in 1928, which is the most consistent growth of any branch of the industry. The value of building granite has fallen for a number of years much below the figure for 1904, and in 1928 was very little in advance of the value attained 24 years previously. The use of granite paving blocks and rubble has shown a gradual decline.

Jan 1, 1931