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To reduce the respirable dust generated by auger-type continuous coal mining machines. The Approach: Use water sprays close to the cutting bits on the auger so that coal fragments are thoroughly wetted as they are formed to prevent dust dispersal into the ventilating air. How It Works: The "wet auger" system of dust control uses water sprays distributed on both shafts of auger type continuous miners. This approach has been tested underground by personnel of the Bureau's Twin Cities (Minn.) Mining Research Center on a Wilcox Mark 20 continuous miner, in a cost sharing contract with Buchanan & Sons Coal Company, Inc. Personnel of the Interior Department's Mining Enforcement and Safety Administration collected dust samples and analyzed the data. A test machine was fitted with six sprays on each auger (see Fig. 1). Water flow rates from 8 to 12 gpm at pressures from 90 to 120 psi, or about 8 gallons per ton of coal mined, were required. At these rates of water usage, mining personnel experienced no problems with work-

Jan 1, 1974

By James R. Boyle

The value of Alabama's nonfuel mineral production in 1983 was $361.3 million, an increase of $61.9 million over that of 1982. The increase reversed a downward trend that started in 1980 and established a new record high for value of nonfuel minerals in the State. Output of most nonfuel minerals increased to some degree with unit value increases creating the record-high value year. Cement, clays, lime, sand and gravel, and crushed stone were the major commodities produced in Alabama. Alabama led the Nation in the production of crushed marble; was second in bauxite; fourth in ferroalloys, dimension marble, common clay, and fire clay; fifth in bentonite and kaolin; and sixth in masonry cement and lime.

Jan 1, 1985

By Ivette E. Torres

The final 26 tables of this chapter, tables 24-49, extend and expand the statistical series on production that was started in the 1963 edition of the Area Reports: International volume of the Minerals Yearbook and that was subsequently updated and expanded in the 1965 and 1967-90 editions. Mainly because of the separation of the countries that formed the U.S.S.R., the column that provided a 5-year average, was deleted. The listing order of major producers, however, continued to be, as in past years, in descending order of rank in the year of review, 1992. This group of tables now includes each of the top 19 crude minerals in 1983 in terms of value of their output plus 3 others of lesser rank. These 22 crude mineral commodities accounted for more than 98 % of the estimated value of world crude mineral production in 1983. Coal production, included in the 1983 value of production table as two separated entries, is combined in one table in this chapter. World output of five key downstream products-aluminum, steel, cement, nitrogen in ammonia, and refined oil-is included because of their significance as products.

Jan 1, 1994

By Edward L. McHugh

The Thousand Lakes Wilderness has no known economically significant mineral resources. However, the geologic setting of the Wilderness indicates a potential for the discovery of geothermal resources. INTRODUCTION The Thousand Lakes Wilderness occupies 16,335 acres (6,611 ha) in eastern Shasta County, California. A mineral resource study of the area was authorized by the Wilderness Act of 1964 (Public Law 88-577). Mining records and published information were examined, and field investigations conducted in 1979. The Wilderness is about 50 miles (80 km) east of Redding and 12 miles (19 km) south of Burney, California. It lies in the Cascade Range of California. Relief is more than 3,000 feet (910 m); elevation is greatest at the summit of Crater Peak, 8,677 feet (2,645 m).

Jan 1, 1982

By W. M. Dressel

A simple, reliable field test for beryllium in rocks has been developed by the Rolla Metallurgy Research Center of the Federal Bureau of Minas. A small portion of the pulverized rock is fused with a sodium carbonate-sodium hydroxide flux in a wire loop. The fused mass is dissolved in water, a few drops of quinizarin solution are added, and the solution is viewed under ultraviolet light. A pink-to-orange fluorescence reveals the presence of beryllium in a sample containing as little as 0.013 percent beryllium (0.26 percent beryl). INTRODUCTION New and potential uses for beryllium make necessary a more intensive search for this metal, which is so similar to aluminum in its chemical reactions that it is not separated from aluminum in ordinary chemical analyses. The principal ore mineral of beryllium is beryl, a beryllium-aluminum silicate, which contains only 5 percent beryllium. This mineral is so similar to quartz in appearance that it is not always possible to distinguish one from the other in the field. While the distinction may be made easily with a petrographic microscope, few prospectors have access to such an instrument, and fewer still know how to use it.

Jan 1, 1960

By D. Eugene Rannels, Yu-Chen Lee

"Lee, Yu-Chen, and D. Eugene Rannels. Alveolar macrophages modulate the epithelial cell response to coal dust in vitro. Am. J. Physicl. 270 (Lung Cell. Mol. Physiol. 14): L123-L132, 1996.-The response of the alveolar epithelium to coal dust exposure is poorly understood. Coal or other dusts may act on the epithelium directly or indirectly through nearby alveolar macrophages (AM) that produce cytokines and other soluble products. AM and type II pneumocytes (T2P) were thus exposed to dust in coculture to evaluate their possible interactions. Anthracite coal dust PSOC 867 increased synthesis of extracellular matrix (ECM) components by T2P. AM alone did not produce ECM. Similarly, coculture ofT2P with AM (3.75:1) had little effect on epithelial ECM synthesis. In contrast, coculture ofT2P with AM significantly increased PSOC 867 effects on T2P rates of ECM synthesis, ECM fibronectin content, and T2P levels of fibronectin mRNA. AM-conditioned medium did not change the PSOC 867 effect on T2P. Neither control nor PSOC 867-treated AM on Falcon culture inserts (0.45-µm pore size) over T2P stimulated ECM synthesis by either untreated or dust-exposed epithelium. Thus AM-mediated changes in ECM synthesis by PSOC 867-treated T2P require close cell-cell interactions, suggesting a role for cell-cell contact or for short-lived soluble mediators of the AM effects. DEVELOPMENT OF PNEUMOCONIOSIS, a chronic disease of coal workers that results in pulmonary fibrosis and low lung compliance, is associated with inhalation of mineral or coal dust in the work place (14). Although the pathology of pneumoconiosis has been studied extensively, cellular mechanisms that cause changes in lung structure and function are not fully understood. Particulate matter that enters the respiratory system distributes according to size, with larger particles being removed in proximal airways. Dust components of small size may enter distal alveolar region, which is populated by two types of epithelial cells, type I and - type II cells, and by alveolar macrophages (16). Each of these cell types may interact with inhaled particles, but only the effects of coal dust on alveolar macrophages have been studied extensively. Less is known regarding the response of the alveolar epithelium, or of effects on epithelial cell-alveolar macrophage interactions, in the dust-exposed lung.Function of the alveolar epithelium is well known to be influenced by the underlying basement membrane, or extracellular matrix (28). Alveolar epithelial cell extracellular matrix interactions, which may involve modulation of cell migration, attachment, or differentiation (17), are reflected in type II cell morphology, metabolism, secretory activity, hormone responsiveness, lamellar body content, and gene expression (21). The extent to which basement membrane modulates differentiation of the overlying epithelium is determined by both molecular composition and three-dimensional structure of the matrix. Type II epithelial cells in vitro synthesize, secrete, assemble, and degrade a variety of basement membrane components, including laminin, fibronectin, type IV collagen, and thrombospondin (22, 27). How expression of these components is regulated, directly or indirectly, upon exposure of the alveolar epithelium to injury by coal dust or by other particulates remains to be resolved."

Jan 1, 1998

By Byron A. Baker

The Bureau of Mines used a windowed cell to measure the phase-boundary pressures of two related series of gas-condensate fluid mixtures. Normal butane was added to the mixtures incrementally to determine its effectiveness for lowering phase-boundary pressure. All the experimental data were correlated, so that the pressure required to maintain light oils mixed with natural gas in the single phase may be computed for secondary recovery applications. The heavy hydrocarbon parts of the mixtures were distillation fractions of a Gulf Coast condensate. Intermediate normal hydrocarbons in the butane-heptane range and natural gas were added to the fractions in selected proportions, so that phase-diagram pressures of 26 fluids were actually studied. The experimental range of temperatures was 50° to 280° F. Two correlations were developed to represent phase-boundary pressures by means of a polynomial. Independent variables represent natural gas content, disparity of properties of components comprising the mixtures, and temperature. A fourth variable, for one correlation only, was the quantity of normal butane added to the original mixtures. The latter correlation with four independent variables contains 15 coefficients and is estimated to be accurate to 135 psi.

Jan 1, 1973

By Irving Hartmann, F. P. Christofel, John Nagy, E. B. McGibbeny

"INTRODUCTION When permissible explosives are used in c procedure recommended by the Bureau of Mines 5/ they are relatively safe, and, no mine explosions are known to have resulted from this type of blasting. However, unsafe blasting practices - the use of nonpermissible explosives or the improper use of permissible explosives - have caused many serious disasters. In fact, such unsafe practices constitute the third most important cause (exceeded only by electricity and the use of open lights and smoking) of coal-mine explosions in the United States. During 1929-1947, inclusive, 81 explosions, resulting in 475 fatalities, were ascribed to unsafe blasting. 6/The hazards of black powder, dynamite, and other nonpermissible explosives in coal mines have been recognized for many years, and attention has been called to this in numerous Bureau of Mines publications. Not only can these explosives ignite flammable gas-air mixtures readily, but they can also ignite coal dust, as has been illustrated repeatedly in tests and at educational public demonstrations at Bruceton and elsewhere. 7/Research in the Experimental coal mine 8/ of the Bureau of Mines at Bruceton, Pa., and unfortunate experience in commercial mines have proved beyond doubt that improper use of explosives that have passed the official permissibility tests can cause as explosions. In limited tests with a fey American permissibles at Bruceton, and in more, extensive tests with permitted explosives at the Polish experiment station, 9/ explosive charges were fired from steel cannon and freely suspended in coal-dust clouds. In these experiments coal dust was ignited under some conditions. However, it has never been definitely established whether permissible explosives can initiate coal-dust explosions when fired in a coal seam. It is true that a few mine explosions were strongly suspected to have resulted from ignition of coal dust by misuse of permissibles, but in each case other complicating factors introduced some doubt in the minds of the investigators. Full knowledge of the problem is important, because coal dust is present in most blasting operations in coal."

Apr 1, 1952

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

By S. J. Schatzel, W. P. Diamond, F. Garcia

Methane explosions have historically been one of the major causes of fatalities and injuries in underground coal mining operations. Advanced numerical models and predictive modeling approaches have the potential to offer optimized methane control solutions for general mine planning purposes and to address specific methane-related operational problems. This paper describes the development of reservoir models for the longwall mining environment and their application for investigating the influence of various completion design parameters on the methane drainage effectiveness of gob gas ventholes. The influence of increasing longwall panel width on the effectiveness of current gob gas venthole completion and placement strategies in the Pittsburgh Coalbed were evaluated and optimized designs developed to capture the expected increase in methane emissions on the larger panel.

By Warren D. Longwill

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Jan 1, 1981

By R. G. Bottge

To better understand those factors which increase mining costs in Alaska, a Bureau of Mines study was conducted to compare the estimated costs of operating a 100,000-tpd open pit copper mine located on a hypothetical ore body in the Lake Clark area, Alaska, with the costs of mining a similarly sized hypothetical copper ore body near Tucson, Ariz. The information derived should be beneficial to the State and Federal governments in appraising the potential for development of large, low-grade porphyry copper deposits in south-central Alaska. Conventional mining and concentrating methods were assumed, and capital and operating costs were derived using flowsheets and standard costing methods. The total price required for copper mined in Alaska and Arizona was $1.12 and $0.63 per pound, respectively, plus or minus 20 percent. These values were obtained assuming no leaching of low-grade copper, recovery of gold, silver, and molybdenum as byproducts, 100-percent equity financing, and a 12 percent discounted cash flow rate of return. The average domestic and international prices for copper in July 1973 were $0.60 and $0.916 per pound, respectively. The existence of a developed transportation and power system in Alaska would have reduced capital and operating costs subs tantially. The required price for copper would have declined from $1.12 to $1.05 per pound, plus or minus 20 percent.

Jan 1, 1974

By John F. Papp

International and U.S. chromium material flow, losses, and environmental releases and transfers from mining through industrial processing, end use, and recycling are identified and quantified. Average (1983-92) U.S. consumption has been: metallurgical industry, 87 pct; chemical industry, 10 pet; and refractory industry, 3 pct. Average chromium content of aluminum, cobalt, copper, nickel, and titanium alloys and alloy, carbon, and stainless steel alloys was estimated. Anthropogenic chromium consumption was estimated for the cement and copper industries. N on-commodity cycle anthropogenic chromium mobilization resulting from U.S. fuel and fertilizer use was estimated. Commodity cycle anthropogenic world chromium loss from mining and primary consumer industry was estimated to be equivalent to about 56 pct of chromium contained in chromite ore production and represented a loss rate of 181 kt-Cr/Mt-CrOre. Chromium released to the atmosphere from natural and from anthropogenic sources were comparable in magnitude. Chromium released to soil was mostly from anthropogenic sources, and aquatic releases were all anthropogenic. Domestic product chromium losses exceed process losses by more than a factor of 10 showing the importance and potential environmental impact of post-consumer recycling. The location of historical and current domestic chromium industry processing sites in 23 States were reported. Chromium releases and transfers to the environment were estimated from 1973 through 2002 by primary consumer industry. A decrease in chromium releases and transfers to the environment was anticipated.

Jan 1, 1995

By T. Kessler

Spark-source mass spectrometry has been used to determine the amounts of minor and trace elements in coal particles of various sizes, including the respirable range (<5 microns). Fifty-six elements ranging in concentration from 0.1 ppm wt to 5,000 ppm wt have been determined. The investigation of coal and coal ash has shown that the organic material in coal does not interfere with the spark-source determination of the various elements.

Jan 1, 1971

By Fred C. Turin, Jasinder S. Jaspal, Alan G. Mayton, William J. Wiehagen

Dump site injuries occur in all major mineral industries. Working in elevated areas near an edge is a common hazard for operators of off-highway mobile mining equipment. In this Information Circular (IC), serious injuries involving haulage trucks working at dump sites are examined for the period 1988 to 1997. Data were acquired from injury reports gathered by the Mine Safety and Health Administration (MSHA). The IC is organized into three sections. The first presents an overview of the frequency and severity of injuries. The second analyzes injury characteristics using MSHA-defined data fields and author-defined injury classifications. Key findings are discussed in the third section. In summary, 370 serious injuries were identified that involved trucks at dump sites, of which 26 were fatalities. Although haulage truck activities at dump sites resulted in a small proportion of the total number of injuries at surface mines, these injuries were much more likely to result in death or significant amounts of lost time than most other surface mine injuries. These findings support the belief that haulage truck activities at dump sites are worthy of continued study by those interested in improving the health and safety of workers at surface mines.

Jan 3, 2001

By Steven J. Page, John A. Organiscak

Laboratory crushing experiments were conducted on a range of low- to high-volatile bituminous coals to investigate the various factors influencing airborne respirable dust (ARD) generation. This research was conducted to identify the principles of ARD liberation from the coal product. Five U.S. bituminous coals were uniformly prepared and processed through a double roll crusher located in a low-velocity wind tunnel. Experimental factors studied included inherent coal seam constituents, coal grind ability, specific energy of crushing, product size characteristics, dust cloud electrostatic field, and specific ARD generated. The results of this investigation indicate that a combination of several factors are associated with ARD generation. One factor is the effect of coal rank, described by the inherent moist fuel ratio, on the product size characteristics, defined by Schuhmann size function parameters. Another key factor is the effect of air dry loss(ADL) moisture in the coal seam on the breakage-induced electrostatic field of airborne dust. The effect of these factors is that different percentages of <10-m coal particles are dispersed as ARD. A discussion of electrostatic field principles, coal ADL, and its effect on ARD generation is presented.

Jan 10, 1998

By Avery H. Reed

RECORD production of marble, kaolin, scrap mica, and talc high-lighted the mineral industry of Alabama in 1962. Among the States, Alabama ranked second in scrap mica, third in the production of bauxite and native asphalt, and fifth in iron ore. The mineral industry of Alabama was dominated by mining and processing of coal and iron ore, and the manufacture of cement, which together comprised 73 percent of the total value of production, compared with 72 percent in 1961. Other important industries were the production of crude petroleum, and stone quarrying. Leading companies were Tennessee Coal & Iron, Southern Cement Co., Southeastern Electric Generating Co., Alabama By-Products Corp., and U.S. Pipe & Foundry Co.

Jan 1, 1963

By Donald E. Buck

In 1988, Albania&apos;s centrally planned economy continued to decline. The country&apos;s officially published yearend economic report did not contain concrete results such as the growth of national income or industrial output. 2 The shortfall for central budget earnings for 1988 amounted to 9% below the planned target. Losses in industry were attributed to poor management and organization, as well as to low technical standards and excessive consumption of fuels and raw materials. The construction, energy, and mining sectors of industry did not meet their annual production plans. As in 1987, within these sectors, the chromite and petroleum extracting and processing industries continued to lag in output. Both chromite and petroleum remained Albania&apos;s chief sources of foreign exchange; the production downturn of these commodities continued to negatively affect the country&apos;s foreign trade position, especially in view of constitutional prohibitions against using foreign credit to finance trade. The chief events in the minerals industry in 1988 included the construction startup of the first of four planned new concentrators at the Bulquize chromite mine, as well as the construction startup of new ferrochromium capacities at Elbasan. Also, the copper mining industry reported the completion of facility expansion at the Perlat mine in the Mid-rite district. Albania began new facility construction at the Dinamo heavy-equipment enterprise at Tirana to maximize self-sufficiency in mining equipment production. Upon completion, the new factory would double the out-put of mining equipment at the enterprise and would introduce new designs for electric trucks and pneumatic drills for the mining industry. The new facility would also increase the production of new machinery and equipment for the country&apos;s beneficiation plants.

Jan 1, 1990

By John Organiscak

A majority of continuous mining machines employ a water spray system and a machine mounted flooded-bed scrubber to suppress and capture dust during coal mining. These machine mounted dust control systems must be designed to function within the localized face ventilation system at the mining section to control both dust and methane. Spray systems can impede or improve the scrubber effectiveness in controlling dust or methane at the mining face. Laboratory experiments were conducted to examine the effect of spray type, spray pressure, machine body blocking sprays, and scrubber airflow on dust and gas levels while using a 12.2 m (40 ft) exhaust ventilation curtain setback from the face. These experiments were conducted with the mining machine positioned at the end of a simulated 6.1 m (20 ft) sump and slab cut. Results indicate that the hollow cone nozzles with blocking sprays best complemented the flooded-bed scrubber performance in an exhaust ventilation system. This external spray system notably reduced dust and gas levels on the off-curtain side of the mining machine for both the sump and slab cut as compared to the flat spray nozzles. Higher scrubber airflows reduced dust and gas levels on the curtain side and in the return of the continuous mining machine. The remote operator position, located on the off curtain side and parallel to the inlet end of the exhaust curtain, sustained the most stable and lowest dust levels around the mining machine.

Jan 1, 2010

By P. -É. Boileau, M. Smets, T. Eger, J. Boutin

Long-haul dump (LHD) vehicles used in underground mining are known to expose workers to important levels of whole-body vibration1. These vehicles are generally designed without suspension and may be categorized as small or large LHDs depending on whether their respective load capacities are lower or larger than 3.5 cubic yards. While the majority of older vehicles are equipped with a rigid or unsuspended seat, more recent LHDs often incorporate a suspension seat. The objective of this study was to define the vibration spectral characteristics of most commonly encountered large and small LHD vehicles operating in mining operations. This was done in an effort to categorize the vehicles in terms of vibration spectral classes to be reproduced on a laboratory whole-body vibration simulator to assess the vibration attenuation performance of a typical LHD suspension seat. Methods Vertical vibration measured at the seat attachment point of 8 small and 8 large LHD vehicles operating underground in typical mining operations under loaded and unloaded conditions was considered as the basis for defining the spectral classes. By regrouping the data collected for each LHD vehicle size and load condition, the overall distribution of acceleration power spectral density (PSD) of measured floor vibration was determined over the 0.5 to 20 Hz frequency range. Mean and envelopes of maximum and minimum values of PSD spectra were computed to define the spectral classes, along with the corresponding values of frequency weighted rms acceleration determined in accordance to the ISO 2631-1 standard2. These spectra were further used to calculate the displacements needed to drive a whole-body vibration simulator consisting of a platform supported by two servo-hydraulic actuators having a total stroke of ±100 mm. For validation purposes, the vibration acceleration spectra measured on the simulator were compared with the target spectra representing the spectral classes. Finally, the vibration transmissibility characteristics of a typical suspension seat were determined under sine sweep excitation using both a rigid mass load and a human subject having a mass of 62 kg and 85 kg, respectively. The SEAT value, representing the ratio of seat to base frequency-weighted rms acceleration, was further measured under each of the defined LHD vibration spectral classes by loading the seat with an 85 kg subject. Tests were repeated three times and the mean SEAT values were determined to assess the seat’s ability to reduce exposure to whole-body vibration in LHD vehicles. Results Three spectral classes applicable to both loaded and unloaded conditions were defined as shown in Figure 1: one for large and two for small LHDs. The influence of load on frequency-weighted rms acceleration was found to be negligible for large and Class I small LHDs, while a shift of the peak acceleration PSD to lower frequencies was noted for the loaded vehicles. The influence of load was found to be more important for Class II small LHDs. Table 1 provides a

Jan 6, 2006