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By F. A. Rutledge

"The chromite deposits of Red Mountain, 10,miles southeast of Seldovia, Alaska, are in an intrusive of ultramafic rocks. The earliest reference to the deposits was made by U.S. Grant3/; J.B. Mertic, Jr. 4/ made a brief examination in 1917; and A.C. Gill5/ spent 7 weeks studying the ore bodies and geology of the region in 1918. The Federal Geological Survey had a field party in the region from July until September 1940 and the Red Mountain area was mapped and geological data were assembled by P.W. Guild.6/A preliminary investigation of the Kenai chromite deposits was made in July 1941 by R. S. Sanford,7/district engineer of the Bureau of Mines, accompanied by P. W. Guild, assistant geologist of the Geologi¬cal Survey. This was followed by surface sampling and core drilling, which were completed in September 1942 under the direction of John W. Cole,8 associate engineer of the Bureau of Mines. G. O. Gates, associate geologist, and A, B. Unkelsbay, junior geologist, of the Geological Survey, logged cores and interpreted geologic features revealed by Bureau of Mines drilling and trenching.9/J. C. Roehm, associate engineer of the Territorial Department of Mines; examined the Red Mountain area in august 1941.10/Additional exploration of other deposits in. the Red Mountain area was completed during the summer of 194. Work consisted of surface sampling, core drilling, and mapping. G. O. Gates, associate geologist of the Geological Survey, spent 4 days in August investigating results of the Bureau of Mines program.Throughout the exploratory work conducted by the Bureau of Mines the cooperation of Red Mountain Chromite, Inc., and especially of John Blodgett, Jr., and Collis 2, Druley, president and superintendent, respectively, was greatly appreciated. Use of their camp in the Windy River cirque and shops at Kasitsna Bay facilitated the Bureau of Mines program."

Apr 1, 1946

By J. Drew Potts

The U.S. Bureau of Mines identified respirable dust sources and controls on four continuous auger mining sections, two with relatively low dust levels and two with high levels. Factors adversely affecting dust levels included auger equipment design, continuous haulage, and low seam height. Dust controls included ventilation practices and spray systems. Maximizing airflow seemed to reduce dust levels most. Air leakage and shock loss can be reduced by constructing stoppings with brushed-on mortar containing fiberglass and by keeping areas between curtains and ribs free from obstructions and storing equipment not essential for face activities in outby crosscuts. Curtain configuration, setback distance, and installation can also affect dust levels. Use of both blowing and exhausting curtains is the most effective configuration. Setbacks from the face should not exceed 15 ft. Installing brattice curtains at least 5.5 ft from ribs, when entries are 26 ft wide, minimizes velocity head. Installing curtains tightly against the mine roof and floor helps maintain a forward airflow movement in the center of the mine heading; curtain overlap can create a tighter seal. The wet-auger spray system also effectively controls dust, provided the mine is already exercising good ventilation practices.

Jan 1, 1989

This is the initial issue of STATE MINERAL SUMMARIES. This publication provides estimated data and summaries of mineral activities at the State level for 1988. Most of the estimates are based on nine months data. These summaries have been prepared in cooperation with State geological surveys or related agencies. Individual State summaries are published separately as State Mineral Industry Surveys and copies can be obtained from the appropriate State Activities field office.

Jan 1, 1989

By R. P. Vinson

Assessment of workplace exposures is an important tool for helping to minimize dust-related occupational illness and diseases. Real-time particulate monitoring can effectively locate areas where dust controls are needed and determine how well they are working. An affordable, person-wearable, real-time dust monitor is needed. The SKC Inc. Dust Detective (SKCDD) fulfills those requirements (Disclaimer: Mention of any company or product does not imply endorsement by NIOSH). The SKCDD consists of a disposable sampling tube (DST) connected to a small hand-held sampling pump. The SKCDD was developed through a Cooperative Research and Development Agreement (CRADA) between the National Institute of Occupational Safety and Health (NIOSH) and SKC Inc. The relationship of dust concentrations measured by personal gravimetric samplers to those measured by the SKCDD was determined in a laboratory aerosol chamber. A comparison of the means and the relative standard deviation of triplicate measurements of each type of sampling device demonstrated the SKCDD to be a viable alternative means for measuring dust. While it provides accurate measurements for specific coal types, it requires correction factors (those correction factors still need to be calculated) for other coal types.

By Orlando Martino

This regional report covers the mineral industries of Canada and 40 countries and territories in Latin America and the Caribbean Basin. Also included is a brief description of the mineral potential of Antarctica. The Latin American region encompasses an area twice that of the United States. Latin America and Canada have a rich and diversified endowment of mineral fuels, metals, and industrial minerals. Tables 1 and 2 provide a summary view of Latin America and Canada's output of its major mineral commodities in world mineral supply in 1991 (revised) and 1992. Table 3 shows the relative importance of a selected group of minerals produced in Latin America in the world mineral economy.

Jan 1, 1994

By Office of Public Information

"The Bureau of Mines was established in the public interest to conduct inquiries and scientific and technologic investigations concerning mining and the preparation, treatment, and utilization of mineral substances; to promote health and safety in the mineral industries; to conserve material resources and prevent their waste; to further economic development; to increase efficiency in the mining, metallurgical, quarrying, and other mineral industries; and to inquire into the economic conditions affecting those industries. The organic act of the Bureau, as amended by Congress and approved February 25, 1913, made it the province and duty of the Bureau of Mines to ""disseminate information concerning these subjects in such manner as will best carry out the purposes of this Act.""In accordance with this directive, the Bureau reports the findings of its research and investigations in its own series of publications and also in articles that appear in scientific, technical, and trade journals; in proceedings of conventions and seminars; in reference books; and in other non-Bureau publications. The number of these reports, the wide range of subjects they cover, and the variety of mediums in which they appear make the kind of list and index presented in this special publication both necessary and valuable.·This issue of the Bureau of Mines. List of Publications and Articles describes reports and articles published during the period January 1, 1985, to December 31, 1989. It supplements the 50-year list of Bureau publications issued from July 1, 1910, to January 1, 1960;1 the 50-year list of articles by Bureau authors published outside the Bureau from July 1, 1910, to January 1, 1960;2 the 5-year lists of publications and articles from January 1, 1960, to December 31, 1964,3 from January 1, 1965, to December 31, 1969,4 from January 1, 1970, to December 31, 1974,5 from January 1, 1975, to December 31, 1979;6 and from January 1, 1980, to December 31, 1984.7"

Jan 1, 1990

By Donald W. Mitchell, John Nagy

Observations made on coking of coal, deposition of soot, dust transport, flame, violence, and related phenomena following experimental coal-dust explosions are summarized. Data are given on gas explosion pressure, flame length, flame velocity, and variation of these parameters with concentration. Conclusions from these observations are useful in preventing similar occurrences in operating mines and serve as a guide in improving safety.

Dec 1, 1963

By Fred N. Kissell

In This Chapter [Instruments available to measure methane in mines and tunnels Using a portable detector in both accessible and restricted spaces Machine-mounted monitors: placement and response time Calibration of catalytic detectors for different gases and Misinterpreting warning signs This chapter gives guidelines for methane measurement in mines and tunnels. The emphasis is on the measurement procedure and the interpretation of the measurement rather than on the instrument itself.] The failure to properly sample for methane is a major contributing factor to methane explosion risk. Sampling errors are most likely to occur at mines or tunnels where the presence of methane is not suspected or during nonroutine tasks at mines or tunnels known to have gas. More specific information on methane sampling at continuous miner sections is in Chapter 3. Chapters 4 and 5 discuss sampling at longwall sections, and Chapter 14 discusses sampling at tunnels. METHANE DETECTORS FOR MINING Many models of gas detectors are available to measure methane concentrations, as well as most of the other contaminant gases found in mines and tunnels. An example is the iTX Multi-Gas Monitor, a portable gas detector available from Industrial Scientific Corp., Oakdale, PA. This handheld instrument measures several gases simultaneously. The cost (2004) ranges from $1,300 to $2,200, depending on the number of gases measured. Similar instruments are available from other manufacturers. Most methane detectors used in mining use a catalytic heat of combustion sensor to detect methane and other combustible gases. These have been proven through many years of reliable operation. For detection of methane, proper operation of catalytic heat of combustion sensors

Jan 6, 2006

Ohio has an estimated 46 billion tons of coal beneath 12,000 square miles of the eastern third of the state. Recoverable coal reserves within this vast area are estimated at 21 billion tons, 3.2 billion tons of which have been mined since 1800. Ohio is the eleventh-largest coal- producing state in the nation and ranks third nationally in coal consumption. Coal resources in Ohio lie in as many as 60 identifiable coal seams along the northwestern flank of the Appalachian coal basin. Except where interrupted by minor faults and erosional discontinuities, these rocks dip gently and uniformly to the east, simplifying the mining methods needed to extract the coal. Fourteen of Ohio's 60 coal seams are considered to be important, although only a small number of seams are currently being mined. Ohio first enacted a surface coal mining law in 1948, requiring in part a $100 per acre reclamation bond. Ohio progressively strengthened its surface mining law in 1949, 1955, 1959, 1961, 1965,1972,1975,1978, and 1981. At the time of its enactment, Ohio's 1972 mining law was one of the most stringent in the country. This law also created a state coal severance tax of four cents per ton to be used for abandoned mine land reclamation. Ohio received primacy to regulate the surface coal mining operations within the state August 16,1982. Its Abandoned Mine Land Program was approved on the same date.

Jan 1, 1992

By Lloyd R. Michels, Burke Cartwright, S. F. Ravitz

"INTRODUCTION Frequent attempts have be,made in the electrolysis of molten magnesium chloride to regenerate the electrolyte by allowing the chlorice generated at the anwdo to read with magnesium oxide and carbon within the melt according to the following reactions: (1) MgO + C + CL2 = MgCl2 + CO,(2) 2MgO + C + 2C12 = 2MgC12. + CO2.The principal advantages of such a procedure are that (1) the direct source of magnesium is magnesium oxide rather than the more expensive dehydrated magnesium chloride and (2) it is not necessary to handle or dispose of large quantities of chlorine or hydogen chloride.Grätzll 5/ proposed the use of an MgO carbon feed in a more or,less compact form in the anode compartment, of the cell. In a patent issued to Magall Aktiengecellschaft, 6/ a compact mixture of MgO and carbon is used as the anode itself. Kato 7/ and Backer 8/ add the feed in finely divided form to the surface of the anode compartment. The Bureau of Mines 2/ recently made a pilot-plant investigation of the electrolysis of suspension of MgO and carbon from chloride melts, in which it was found that although,current efficiencies of 60 to 70 percent were obtainable, the formation of sludges containing MgO, carbon, and magnesium seriously interfered with the operation of the cell,"

Apr 1, 1945

By Paul M. Tyler

"In preparing this paper the writer has perforce depended mainly upon published information, including the catalogs and pamphlets issued by importers and dealers such as the Diamond Drill Carbon Co. and J. K. Smit & Zonen. Special acknowledgment is made to various articles published by S. H. Ball. The writer of this paper, however, is alone responsible for statements herein contained and since he has often found it necessary to rationalize apparently conflicting opinions of recognized authorities on this little-known subject, he will welcome constructive criticism from the trade.Two types of diamond are extensively used for industrial purposes. One type, known as bort or bortz (boort, boart, bowr, etc.), consists of diamonds of the gem variety but unfit for cutting into gems. They may be colorless, yellow, brown, or gray. The other type, carbonado, known in the trade as ""carbon"" or ""black diamond,"" differs greatly from the white diamond, being opaque and apparently amorphous or noncrystalline. Actually, instead of forming a large single crystal as in a gem stone, carbon diamond comprises a mass of microscopic crystals that interlock to form a tough, homogeneous material with no planes of cleavage. It is found in various colors -- black, dark green, brown, and gray -- but usually it has .a dark lustrous black surface, with a resinoid or submetallic appearance, often resembling fine-grained steel. Upon exposure to the air the broken surface gradually darkens to an ash-gray color. Ballas is a special type of carbonado in which the crystals are definitely-oriented around a central nucleus. They are harder and tougher than ordinary carbonado but are much scarcer. The Cape ballas is reputed to be not quite so tough as Brazilian ballas but tougher than carbon or bort.The diamond crystals are isometric and take a variety of forms. The cleavage is octahedral and well marked. A crack is easily -started parallel to an octahedral face, and bort or gem diamonds are notoriously brittle, especially when subjected to sudden shock. Even carbonado, while it has a high resistance to slowly applied pressures, may be chipped or broken by a sharp blow.Exposed to radioactive rays, the diamond becomes phosphorescent; this property is often utilized to distinguish it from quartz, topaz, or glass. The unusually high refractive index likewise aids in its identification in the case of a more or less transparent stone. At the temperature of the electric arc, diamond is converted into graphite, another form of Carbon but one of the softest mineral substances. At a much lower temperature, as low as 1,5620 F., the diamond may be burned like ordinary carbon in an atmosphere of oxygen, and according to some authorities there is danger of burning a diamond if overheated even in air."

Mar 1, 1932

Assess the technical feasibility of mining small and/or deeply buried frozen placer deposits from the surface through boreholes.

Jan 1, 1997

By Alan Mayton, Bertrand Valero, Christopher Jobes, Farid Amirouche

Exposure to vibration induced in and around underground mine’s exploration is a major concern to vehicles operators. Most of these drivers over time develop serious spinal musculoskeletal and discs problems causing low back injuries. The first purpose of this paper is to analyze the performance and dynamic response of driver/operator when subjected to different levels of vibration due to rough road conditions depicted in a mine field. The second purpose of the paper is to quantify the energy transmission in the presence of seat padding with special characteristics and active suspension. Using experimental testing data collected at NIOSH/PRL (National Institute for Occupational Safety and Health/ Pittsburgh Research Laboratory) along with model simulation algorithms developed at the University of Illinois at Chicago we investigated how acceleration transfer functions as well as absorbed power affects the different parts of the body. To this end, we used a previously validated human model which includes the head, torso segments and legs. The connective forces between body segments were modeled through modal analysis techniques from previous experimental data at the UIC Vehicle Technology Laboratory. The absorbed power and energy transmitted to the body are used as an index measure to assess the viability of the different seat padding’s and active seat suspension control strategies.

By R. Hogg, S. Chander

"INTRODUCTION The behavior of particulate systems in general is determined by the properties of the solid and fluid phases and of the interfaces between them. As particle size is reduced, the inter facial effects become increasingly important until, in colloidal systems, they become completely dominant. Interfacial phenomena are especially important in coal processing for a variety of reasons. Because coal is naturally hydrophobic and its density is low, surface forces begin to dominate over gravity at relatively coarse sizes. Coal is thermodynamically unstable in the presence of air, so that surface oxidation occurs readily leading to important variations in surface properties with time and environment. These effects are further compounded by the inherent heterogeneity of the material.Surface characteristics and properties play a significant role in most aspects of coal processing. Comminution, for example, is a process of creating new surface, while agglomeration involves the reduction of surface area and is usually controlled by surface forces. Both solid-solid and solid-liquid separations are influenced by interracial phenomena, Gravity separations are usually performed in a liquid phase and are affected by the wetting characteristics of the various solids present and by the need to ensure proper dispersion of the individual particles. Froth notation, of course, separates particles on the basis of differences in surface characteristics. Chemical processes such as leaching generally involve interfacial reactions whose rates depend on surface area and may be influenced by electrochemical effects in the electrical double layer at the solid-liquid interface, or by adsorption of reactant and/or product species from solution. Solid-liquid separations and associated processes such as flocculation are strongly dependent on the nature and properties of the solid-liquid interface.In characterizing solid surfaces, it is important to consider first the surface area, since this determines the relative importance of the interfacial effects. The structure and chemical composition of the surface may depend on the distribution of different petrographic constituents and impurities such as finely disseminated mineral matter, on the extent of surface oxidation, and on adsorption from the environment. These, in turn, will generally determine the surface properties which define particle behavior. Since the relationships between structure etc. , and properties are not generally known, it is usually necessary to measure properties such as wettability and electrical charge directly."

Jan 1, 1989

By P. -É. Boileau, S. Mandapuram, Shiping Ma, S. Rakheja

The absorbed power (PAbs) has been suggested as a better measure of human responses to whole-body vibration, since it relates to the cumulative energy dissipated by the body exposed over a given duration. Moreover, unlike the other measures, the PAbs can adequately account for the intensity of exposure. Although, the vast majority of off-road vehicles impose considerably severe vibration along the horizontal axes, the vast majority of studies on biodynamic response characterization consider only vertical vibration. Only a few studies have reported PAbs responses of the seated human body exposed to horizontal vibration and the major contributing factors [1]. This study aims to characterize the PAbs responses of seated human subjects to horizontal (uncoupled x- and y-axis) vibration as functions of the vibration intensity, subject mass, seat height and the, type of back support. Methods Experiments were conducted using a rigid seat with an adjustable backrest inclination and seat height. The seat was installed on a horizontal vibration simulator and the forces at the seat base and the backrest were measured by three-axis force plates. Two single-axis accelerometers were installed on the seat back and the platform, oriented along the axis of motion. The experiments were performed using three different seat heights (350, 390 and 410 mm), back support conditions (NB- no back support and sitting erect; Wb0- Upper body supported against a vertical back support; and WbA- back supported against an inclined backrest, while sitting relaxed) and three different magnitudes of broad band excitations in the 0.5-10 Hz frequency range (0.25, 0.5 and 1 m/s2 rms acceleration under x-axis and y-axis, applied independently). A total of 8 healthy adult male volunteers with total body mass ranging from 59.4 kg to 92 kg and aged between 21-51 years took part in the experiments. The subjects were seated with their hands in lap, and feet supported on the moving platform for each posture. Each measurement was repeated 2 times, while the data were analysed using a bandwidth of 50 Hz and frequency resolution of 0.0625 Hz. [ ] The data were analyzed to derive the absorbed power characteristics of the body at both seat pan and backrest interfaces, while the coherence among the measured forces and accelerations wer

Jan 6, 2006

By Sean Gallagher

Background. There is currently little information regarding factors associated with specific modes of motion segment failure using a fatigue failure model. Methods. Thirty-six human lumbar motion segments were fatigue tested using spinal compressive and shear loads that simulated lifting a 9 kg weight in three torso flexion angles (0°, 22.5°, and 45°). Twenty-five segments failed via fatigue prior to the 10,000 cycle maximum. These specimens were visually inspected and dissected so that the mode(s) of failure could be determined. Failure modes included endplate fractures (classified into nine varieties), vertebral body fractures, and/or zygapophysial joint disruption. Logistic regression analyses were performed to determine whether certain morphometric variables, amount of motion segment flexion, disk degeneration scores, and/or loading characteristics were associated with the occurrence of specific failure modes. Findings. Results indicated that stellate endplate fractures were associated with increased posterior shear forces (P < 0.05) and less degenerated discs (P < 0.01). Fractures running laterally across the endplate were associated with motion segments having larger volumes (P < 0.01). Endplate depression was more common in smaller specimens (P < 0.01), as well as those experiencing increased posterior shear force (P < 0.05). Zygapophysial joint damage was more likely to occur in a neutral posture (P < 0.01). Interpretation. These results suggest that prediction of failure modes (e.g., specific endplate fracture patterns) may be possible (at least for older specimens) given knowledge of the spinal loads along with certain characteristics of the lumbar spine. Published by Elsevier Ltd. Keywords: Lumbar spine; Endplate fractures; Zygapophysial joints; Morphometry; Disk degeneration; Motion segments; Aging

Jan 1, 2006

By Charles E. Larson

Square Butte has no history of mineral development or production. Surface mapping, radiometric surveys and chemical analyses of rock samples reveal no mineral potential. The area has a speculative potential for petroleum and natural gas. INTRODUCTION The Square Butte Instant Wilderness Study Area, in Chouteau County, Montana, consists of 1,946 acres (788 ha) about 35 miles (56 km) southeast of Fort Benton and 50 miles (80 km) northwest of Lewistown (fig. 1). This study was performed under provisions of the Federal Land Policy and Management Act (Public Law 94-579, October 21, 1976), in conjunction with the U.S. Geological Survey, which is responsible for regional geological, geochemical, and geophysical investigations, and the U.S. Bureau of Mines, which determines the mineral potential of existing mines, prospects, or mineralized areas.

Jan 1, 1982

By G. W. Jones

[One of the mJor c~ctivities of the Bureau ~f l;ine;: is the j.a-onotion of sdetp in mining a.nJ other inclus tries. 13 cor&apos;ncc tlcn td t~l tiiene activities the 3~.sccu r:e termine? t&apos;le cwl.os:lon ha~arls 95 n,o;r.?xs tibla Tases, vzpor s, aid scli3s aqi iavestig~ ter rnrI.?ns of controlling s-~fi. prevpri ting eqlosians.]

Jan 1, 1941

By G. W. Jones

[One of the mJor c~ctivities of the Bureau ~f l;ine;: is the j.a-onotion of sdetp in mining a.nJ other inclus tries. 13 cor&apos;ncc tlcn td t~l tiiene activities the 3~.sccu r:e termine? t&apos;le cwl.os:lon ha~arls 95 n,o;r.?xs tibla Tases, vzpor s, aid scli3s aqi iavestig~ ter rnrI.?ns of controlling s-~fi. prevpri ting eqlosians.]

Jan 1, 1941

By Ronald B. Stotelmeyer

This report summarizes the U.S. Bureau of Mines evaluation of the mineral resources of eight roadless areas in several National Forests in Montana. The areas are amoung those that have been proposed as additions to the National Wilderness Presevation System In various sessions of the U.S. Congress. Mineral Commodities present include gold (lode and placer), silver, copper, lead, zinc, molybdenum, tungsten, rare-earth elements, fluorite, and barite. Numerous mineral deposit types occur. Past production was from gold placers and vein-type deposits. There is potential for development of large volume porphyry copper-molybdenum, disseminated gold, stratabound copper-silver, and exhalative massive-sulfide metallic deposits. A substantial increase in metal prices is needed before any known vein-type deposits will be economic.

Jan 1, 1994