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By Louis C. Brichta

The Rush Creek district of Marion County, Ark., has had a more or less continuous record of zinc production over the past 40 years. The ore has come from many small mines working on oxidized and semi-oxidized deposits found in the Everton formation where that formation forms the present surface rock. Prospecting has been restricted to the hillsides above the creek levels, the actual ore outcrops being the guides. Little attention has been paid the possible sulfide zones. In August 1942, the United States Geological Survey and the Bureau of Mines recommended exploration of the Powell and Cotter formations, which underlie the Everton, for which purpose the Survey had previously located 18 proposed drill-hole sites in geological structures that seemed favorable to are deposition.

Jan 1, 1949

By Robert R. Stein

Occupational noise caused by the rock drills used in mining was investigated by the U.S. Bureau of Mines. Using a large reverberation chamber and an automated drill test fixture (ADTF), the sound power levels of mining drills were measured to determine if there are types of drills that are advantageous from a noise production standpoint. Test results show that while there are not large variations among types of drills, there are still some choices that could produce a positive effect on overall noise exposure. It is also shown that lower noise exposures are possible using larger drills because of higher production rates and better operator positioning.

Jan 1, 2010

By D. W. Butner

This report is concerned with the conditions affecting the methods and costs of mining phosphate rock in that part of the western phosphate field that is in Bear Lake and Caribou Counties in southeastern Idaho ( see fig . 1) . The area was selected because it contains most of the known phosphate reserve and because its geology has been studied more extensively than that of other sections . Deposits of phosphate rock on public land may be leased from the Government under the terms of the Mineral Leasing Act of 1920 , subject to the regulations of the Bureau of Land Management . Public interest in phosphate production is growing , as shown by an increasing number of applications for leases . Two mines are being operated steadily for the production of phosphate rock by companies that have also the necessary processing plants for the manufacture of fertilizer . Total western phosphate - rock production in 1947 is reported by the Economics Statistics and Division of the Federal Bureau of Mines to have been 1,193,000 long tons , mined in Idaho , Montana , and Wyoming . The average grade was 30.7 percent of contained phosphorus pentoxide (P205 ) ; the average value at the mines was $5.67 per long ton . Idaho contributed 905,000 tons , or somewhat more than 75 percent of western production . Western fertilizer plants took 23 percent of total production; 76 percent was exported . Strip mining accounted for 75 percent of the Idaho tonnage; the remainder was stoped from underground workings . Rock must contain a minimum of 30 percent P205 to be commercially useful for the production of superphosphate fertilizer by current acid treatment methods . Research by corporations and Government agencies has been directed toward the use of lower - grade ore . So far , only by smelting can rock containing as little as 25 percent P205 be used economically . Any development of processing or use pattern that would render the mining of , say , 20 percent rock profitable would have important effects in reducing the unit cost of mining . In the search for metallurgical improvements , consideration should be given to the saving of valuable components of the rock, such as vanadium and fluorine , both of which are present in the beds .

Oct 1, 1949

By Kenneth L. Rubow, Virgil A. Marple, Zhigun Zhang

"A theoretical technique has been developed and verified experimentally for determining the aerodynamic diameter of irregular shaped particles. The aerodynamic diameter of a particle is a very important parameter for determining where that particle deposits in the respiratory tract. Many instruments, such as impactors and cyclones, will determine the aerodynamic size distributions of aerosol particles but few analyze the particles individually. The theoretical approach of our technique is to solve, by use of high speed computers, the three-dimensional Navier-Stokes equations to obtain the flow field around an irregular shaped particle of any contour. The computer program will then determine the drag on the particle, and thus the aerodynamic diameter of the particle can be calculated. The experimental approach has been to pass the particles through a centrifuge and collect the particles upon a collection foil. The position of a particle on the foil is an indication of its aerodynamic diameter. These particles were then shadowed in two orthogonal directions and inspected under an scanning electron microscope (SEM). The top view of the particle in the SEM plus the views of the two orthogonal shadows allows one to determine the three-dimensional shape of the particle. Studies have been performed on silica, coal and talc particles with aerodynamic diameters in the 1 to 4 µm size range. The three-dimensional shape, as is determined from SEM analysis, was used in the theoretical computer program and the results compared. It was found that in most cases the agreement between the experimentally and theoretically determined aerodynamic diameters was within 5%. INTRODCJCTIONThe equivalent aerodynamic diameter (EAD) of a particle, defined as the diameter of a unit density sphere with the same falling speed as the particle in question, is an important size measurement of the particle. This is especially true when attempting to predict where particles may deposit in the respirator tract. Therefore, EAD is an important parameter when considering respiratory diseases caused by particles, such as coal workers pneumoconiosis (CWP).Many instruments will measure the EAD size distribution of the aerosol particles, but few analyze the particles individually. Impactors, cyclones and virtual impactors normally collect particles upon substrates or filters which are · then analyzed gravimetrically to determine the mass concentration of the particles in that size classification. The EAD of particles can be measured on an individual basis with centrifuges, inertial spectrometers and the TSI Aerodynamic Particle Sizer (APS). Centrifuges are most ideally applicable for studying individual particles as the particles are deposited, on long removable foils, at locations dependent upon their EAD."

Jan 1, 1990

By W. S. Wright

"INTRODUCTION The Ward copper deposit was brought to the attention of the Bureau of Mines in September 1943 by John J. Knob, 217 E. Penn Street, Long Beach, N. Y. At that time all Bureau of Mines work on Seward Peninsula was being directed to the exploration of deposits of tin, a metal high on the strategic list. It was not until September 1946 that the Bureau could make a preliminary examination of the Ward prospect.ACKNOWLEDGMENTSIn its program of investigation of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual investigative work, and prepares the final report. The Metallurgical Branch, Oliver C. Ralston, chief, analyzes samples and performs beneficiation tests.Acknowledgment is extended to Robert S. Sanford, acting chief of the Alaska division, under whose supervision all exploratory work of the Territory is conducted."

Aug 1, 1947

By Thomas V. Falkie, R. Venkataramani

The empirical nature of this investigation required measurements of variables under operating conditions in underground coal mines. The variables to be measured were based on the postulated character¬istics of the loading function, as described in the previous chapter. One class of variables presumed to influence the loading function are geological variables. Accordingly, the sites for data collection were selected in different bituminous coal seams at dispersed locations in order that variation in geological conditions would exist. Seven mines in central and western Pennsylvania and one mine in northern West Virginia were selected as data collection sites. Five different coal seams were represented by these mines. The remaining classes of variables - geometric, mechanical, and procedural - were measured as they occurred in the mines. A description of the measurements, and the conversion of these measurements to forms which could be-analyzed for effect on the loading function is given. Mining Dimensions At the underground working face, the following dimensions were measured: a. Thickness of coal excavated. b. Thickness of shale excavated. c. Total height excavated. d. Width excavated. e. Depth of penetration of each machine cut. With the exception of the last of these dimensions, all were measured

Jan 1, 1972

By Irving Hartmann

Several recent ignitions of firedamp - a mixture of methane and air - in American coal mines have been attributed to frictional heating when hard rocks were struck while cutting and drilling coal seams. Although none of these ignitions caused severe explosions, they call attention to a problem that can become increasingly significant as mechanized mining is developed further. The power in and rapid release of energy from high-speed machinery has increased the rates of advance into virgin coal creating many problems. Unforeseen faults and hard mineral inclusions may be encountered; coal brought down in this way is finer in size; more gas is released from the seam; it is frequently more difficult to provide adequate ventilation at the' face; and new roof-support problems must be solved. In particular, continuous mining machines (also known as continuous miners) greatly increase the frequency of contact between cutter bits and minerals. In view of these conditions, it may be expected that more gas ignitions will occur as a result of frictional heating unless the situation is understood and remedial measures are introduced. The problem of frictional heating is not new in coal mining. In Europe, particularly in England, it has been a concern for more than a century. During the last 15 to 20 years frictional ignitions have been a major cuase of explosions in British mines. Explanations for the greater number of such ignitions in England may be the special character of the coal measure strata, the mining methods, the rate of gas emission and possibly its composition, and less effective ventilation near the face. To reduce the ignition hazard, considerable laboratory and field research has been conducted, particularly by the Safety in Mines Research Establishment, Ministry of Fuel and Power of Great Britain. Much of the information presented in this report has been drawn from these studies.

Jan 1, 1955

By J. W. Griffith, J. L. Stauffer, L. M. Demers, D. C. Kuhn, S. Riliog

"The relative activation of eicosanoid production which results from the exposure of the alveolar macrophage (AM) to mineral dusts is thought to be a key factor in the pathophysiology of occupational lung disease. We compared in vitro basal and silicastimulated production of prostaglandin E2 (PGE2) and thromboxane A2 (TXA2) by AM from normal humans and non-human primates (Macaca nemistrina). In addition, we instilled mineral dusts directly into one lung of the non-human primate and evaluated AM eicosanoid production at two week intervals following dust instillation. Unstimulated AM from humans produce more PGE2 and TXA2 than do AM from M. nemistrina. However, in vitro exposure of AM from both species to silica dust produced a qualitatively similar increase in TXA2 production accompanied by no change in PGE2 production. Sequential analysis of AM eicosanoid production following a single bolus exposure to bituminous or anthracite coal dusts, titanium dioxide (Ti()i) dust or crystalline silica showed marked variability among individual non-human primates in qualitative and quantitative aspects of dust-induced eicosanoid production. However, the rank order of potency of the different dusts (silica> anthracite> bituminous) correlated with epidemiological evidence relating the type of dust mined to the incidence of pneumoconiosis. These studies suggest that the non-human primate may serve as a model for the study of both the role of eicosanoids in the etiology of dust-induced occupational lung disease and the biochemical basis for individual variability in the response of lung cells to mineral dust exposure. IntroductionOccupational inhalation of mineral dust can lead to chronic debilitating lung disease ( 1,2). One of the key components of the disease process is thought to be the interaction of mineral dust with the alveolar macrophage (AM) and the subsequent release by the AM of inflammatory and fibrotic substances (3,4). Chronic inhalation of mineral dust, depending on the type and amount of dust, may then produce a situation in which ongoing inflammation, accompanied by the destruction of functional lung tissue by products of activated AM and polymorphonuclear neutrophils, stimulates the production of nonfunctional matrix by lung fibroblasts.The AM produces several oxygenated derivatives of arachidonic acid (AA) which may play important roles in dust-induced lung pathophysiology (5,6). In previous studies in the rat, we found that prostaglandin E2 (PGE2). thromboxane A2 (TXA2) and leukotriene 84 (L TB4) were the major AA metabolites produced by AM (7). PGE2 is associated with pro-inflammatory activity (8) as well as anti-fibrotic activity since it downregulates interleukin -1 (IL-1) and tumor necrosis factor (TNF) release by AM (9-11). TXA2 is known to stimulate platelet activity, cause bronchial and vascular smooth muscle contraction (12) and to possess chemotactic activity (13). LTB4 is chemotactic for neutrophils and monocytes (14) and has been suggested as an additional regulatory factor in the release of TNF by AM exposed to silica dust ( 15)."

Nov 1, 1995

By Thomas V. Falkie, R. Venkataramani

Proposing A Model In this investigation, a model of the form: n Y = a0 + E a x. A-1 v=l J J was postulated, where the number of independent variables "n" was originally fifteen. The following experimental hypothesis was to be tested: Null Hypothesis: the coefficients a = 0 J Alternate Hypothesis: One or more of the coefficients a 0 J Correlation and Regression To establish the alternate hypothesis and to test how well the proposed model fits the data, the conventional statistical techniques of correlation analysis and multiple linear regression analysis were used. Additionally, factor analysis was employed to investigate the dependency relationships in the data. Correlation and linear regression are well established statistical procedures in science and engineering. References on these procedures include Spiegel (1961), Anderson (1963), and Draper and Smith (1966). A simple example is stated here. If N observations are made of two variables, x and y, and it is desired to test this data to see if a linear relationship exists, then a model of the form: Y = a0 + a 1 x A-2 is proposed. The values of a0 and al may be calculated from the raw data by the "least square normal equations", which are:

Jan 1, 1972

By L. C. IlsLey

The cool drills that have received the approved of the Bureau of Mines may be divided into three general classes: (1) Hand drills, small drills that are held in the hands or supported against the body while in use; (2) post drills, drills that are too heavy or powerful for hand operation and therefore require some mechanical mounting when in use; and (3) drilling machines. Besides these three classes, drilling equipment has been incorporated in the design n of a number of permissible coal-cutting machines, but such drills are considered an integral part of the cutting machine and are not given separate approval. The hand drills have been described in Report of Investigations 3363, which is cite of several papers that have been published dealing with miscellaneous types of permissible motor-driven mind equipment not covered in bulletins. The present paper describes post drills and drilling machines approved by the Bureau of Mines up to July 1, 1937.

Jan 1, 1938

By L. C. IlsLey

[The cool drills that have received the approval of the Bureau of Mines may be divided into three general classes: (1) Hand drills, small drills that are held in the hands or supported against the body while in use; (2) post drills, drills that are too heavy or powerful for hand operation and therefore require some mechanical mounting when in use; and. (3) drilling machines. Besides these three classes, drilling equipment has been incorporated in the design n of a number of permissible coal-cutting machines, but such drills are considered an integral part of the cutting machine and are not given separate approval. The hand drills have been described in Report of Investigations 3303, which is cite of several papers that have been published dealing with miscellaneous types of permissible motor-driven mind equipment not covered in bulletins. The present paper describes post drills and drilling machines approved by the Bureau of Mines up to July 1, 1937.]

Jan 1, 1938

By James Paone

The Bureau of Mines conducted laboratory drillability studies on nine rock types using two mining-type percussive drills. Percussive-bit action was simulated by dropping a known weight on a rock sample to obtain a coefficient of rock strength for each rock drilled. While no single physical property of a rock is completely satisfactory as a predictor of penetration rate, coefficient of rock strength showed a better correlation with penetration rate than did other physical properties. Results also indicate that over the range of energies investigated, energy per unit volume in a given rock is independent of blow energy. A drillability index for the percussive system is proposed that utilizes the coefficient of rock strength test to determine energy per unit volume for a given rock which, along with the work rate of a given drill and the bit diameter, is used to predict the penetration rate as shown in the following equation: [R = 4P pD2 E, where R = penetration rate, in/min, P = work rate, in lb/min, D = bit diameter, in, and Ev = energy required to produce a given volume of rock, in lb/in3.] Laboratory tests indicate this method's potential as a simple and reasonably accurate method of predicting penetration rates with any percussive drill and bit combination.

Jan 1, 1969

By L. C. IlsLey

In the normal operation of mines, the aggregate effect of many seemingly minor op rations may be very important as respects economy and safety. Anion: these operations is the method employed in coupling and uncoupling mine cars. For economic reasons the equipment in mines has not been protected as well as railroad equipment. It is pertinent that haulage accidents rank second in severity among mine accidents, and that manual coupling of cars has been one of the most frequent causes of such accidents. One study4/ revealed that coupling was responsible for about 20 percent of haulage accidents underground. A review of early conditions on steam railroads, which were responsible for the introduction of safer methods of coupling cars, indicates how conditions in might be improved. THE STORY OF RAILROAD COUPLING As any considerable improvement in mine-car coupling probably will follow lines somewhat similar to those that brought order out of chaos for the railroads, it seems appropriate to review briefly the steps taken to improve railroad coupling from the days of link and pin couplings of various types to the adoption of the standard ?M.C.E? automatic coupler.

Jan 1, 1943

By Todd M. Ruff

The lack of visibility near earthmoving equipment resulted in six fatalities in U.S. surface mining operations during 2003. These accidents were the result of either a piece of equipment striking another vehicle or worker, or the equipment traveling over the edge of an embankment. Figure 1 is an example of a recent accident that resulted in serious injuries to one worker and fatal injuries to two others when a van parked in front of a haul truck. Two fatalities occurred in separate incidents when front-end loaders struck workers. Another two workers were killed when their equipment backed over the edge of a highwall or dump point [1]. There is clearly a need to provide better information to equipment operators regarding their surroundings. [ ] Researchers at the National Institute for Occupational Safety and Health (NIOSH), Spokane Research Laboratory, are working to reduce these accidents by developing systems that sense obstacles and changes in terrain near the equipment and provide this information to the operator. Many off-the-shelf proximity warning systems that were developed for automobiles, light trucks, and recreational vehicles were evaluated on off-highway dump trucks [2]. Many limitations were found with existing systems, including frequent false alarms, limited detection range, a lack of specific information on an obstacle (e.g., location, identity), difficulties in finding suitable mounting locations, and an inability to withstand the environment. These limitations have necessitated the development of new systems designed specifically for large, off-highway, earthmoving equipment. New off-the-shelf systems available for mining equipment include radar and tag-based detection systems. Prototype systems now being developed include a proximity warning system based on the Global Positioning System (GPS) and a computer-assisted stereovision system. Development of these new systems was accomplished by working with manufacturers to modify existing systems to meet the needs of surface mining and through cooperative research with organizations to develop completely new solutions. A typical proximity warning system consists of a sensor or antenna mounted on the equipment that detects the presence of obstacles and an alarm interface in the cab of the equipment. Some systems, as described in more detail below, also require that other vehicles and personnel on the ground be outfitted with electronic tags that transmit an “I’m here” signal back to the system (e.g., radio signal detection systems or GPS). Many types of proximity warning systems are on the market, but they are not all discussed in this paper. APPROACH In past work, engineers at NIOSH evaluated several off-the-shelf proximity warning technologies in order to verify their effectiveness on off-highway dump trucks [2]. Dump trucks were chosen because of the number and severity of accidents involving this type of equipment and because extensive blind areas around these trucks are typical. This experience allowed engineers to limit the number of systems chosen for long-term tests at mine sites to those systems showing

By ALBERT C. DURHAM

In anthracite mining , pumping is a problem of major importance , and water must be handled and rehandled in almost every mine whether the mine is in operation or idle . The motor - driven centrifugal pump is the most commonly used type of unit for the large pumping installations, and experience has . proved that fully automatic control has certain advantages over manual control . Some of these advantages are greater safety for maintenance personnel , continuous protection against faulty operation , which could cause damage to the Lumping apparatus , and lower pump -room operating costs .

Aug 1, 1948

To perform comprehensive economic evaluations on both existing and proposed mineral operations. Approach A comprehensive computer model was developed which is capable of evaluating the economics of an entire mineral recovery operation, including exploration, acquisition, infrastructure, mining, milling, smelting, refining, transportation, taxation, and return of and on capital. How it Works The MINSIM (MINe SIMulator) economic evaluation concept was developed by the Bureau of Mines in 1967. The initial versions used a continuous discounted cash flow rate-of-return (DCFROR) to measure the effect of changes in expected revenues and costs. Subsequent enhancements to the program have expanded and strengthened MINSIM, especially the addition of an option which determines total production cost (i.e., the commodity selling price that a mineral recovery operation would require in order to obtain a target rate of return), an expanded capacity for evaluating by-products from a mineral property, and significantly broadened taxation determining capabilities. The MINSIM computer program uses essentially the same procedures and calculations that are performed in a manual economic evaluation, although the program accomplishes its tasks much more rapidly and accurately, An experienced mineral economist may require a week to evaluate a single mining operation with the same detail and consistency provided by MINSIM in a matter of seconds of computer time.

Jan 1, 1983

The current procedure for measuring the concentration of respirable coal mine dust is as follows. Each filter is preweighed by the filter manufacturer to ±0.1 mg. Following sampling with the Coal Mine Dust Personal Sample Unit (CPSU) at 2.0 L/min, the filter with coal mine dust is sent to MSHA for weighing. The current MSHA procedure for weighing respirable dust samples uses a Mettler Model AE163 analytical balance in conjunction with an automatic weighing system with a precision of ±0.02 mg [Tomb 19901. Each balance is calibrated twice per day. Quality control for the automatic weighing system includes the systematic weighing of one in eight filters on a second Mettler AE163 balance. Tolerance is set at ±0.1 mg between the two weighings of the same sample. Weights are truncated at the 0.1 mg level (e.g., 3.457 mg is truncated to 3.4 mg) [Bowman et al. 19851. The difference of the two truncated weights is then recorded as the weight of coal dust deposited. The respirable concentration (mg/m3) is computed by multiplying by a correction equal to 1.38 and dividing by the volume of air sampled (2.0 L/min x sampling time [min]).

Jan 1, 1997

By L. H. Duschak

"This paper is based on the results of work conducted of the bureau's experiment station at Berkeley, Calif., in connection with the investigation of properties and methods of utilizing Western magnesite. The experiments described herein were made under the supervision of the writer, by W. C. Riddell and E. H. Delius, of the station's staff.In calcining magnesite for the production of magnesium oxide to be used in the preparation of oxychloride cement, the calcium carbonate present in the original rock may remain unchanged or appear in the finished product, either as CaO, or in combination with SiO2, A12O3, etc. As there is reason to believe that free CaO may have an effect on the behavior of caustic magnesia in the cement reaction, it is desirable to have a method for the determination of the relatively small amounts of free CO in the presence of a large quantity of MgO.The extraction of the free CaO with water free from CO2 at once suggests itself as a possible method. The solubilities of Ca(OH2)2 and Mg(OH)2. are given by Seidell in his book an ""Solubility of Inorganic and Organic Compounds."" (2nd Edition, 1919) as follows:"

Jun 1, 1920

By Vladimir Adamek

This paper describes the Bureau of Mines development of a novel subsidence prediction methodology suitable to the mining and geologic conditions in the Northern Appalachian Coal Region. It describes the computation of vertical and horizontal movements, inclination, curvature, and horizontal strains. The substance of this method is the separation of the effects of lithology by introducing a correlation between hypothetically homogeneous overburden and existing lithologic conditions, while providing for different mining conditions, i.e., underground geometry and overburden thickness. The effects of lithology have been expressed in the form of a variable subsidence coefficient within the subsidence trough. The subsidence coefficient is considered a constant for other predictive methods. Field data from 16 test sites at 11 Bureau longwall panel studies were used in the analysis. For each panel, the characteristics of the variability of the subsidence coefficient were defined. Regression analysis of the subsidence coefficients from all test sites on their locations relative to the edges of their respective panels yielded a third-degree polynomial equation. The results from additional longwall panel studies, not included in the regression analysis, were used to prove the validity of this method. To facilitate the use of this precalculation methodology, a computer program was written in BASIC for use on a personal computer.

Jan 1, 1987

By David Hoadley, Kenneth R. Maser, Ashok B. Boghani, James E. Billar, D. Randolph Berry, Mackenzie Burnett, Robert H. Trent

D.2 Principal Types of Coating A Sodium Silicate Sodium silicate is a good fire retarder when freshly applied, but it loses its effectiveness if the relative humidity is at all high, thus exposure to a relative humidity exceeding 65 percent causes a serious decrease in the effectiveness after only one month. In fire, sodium silicate swells to a frothy mass (intumescence) which hardens and insulates the wood against heat. This property is destroyed by exposure to moisture. Manufacturers of many of the proprietary paints containing silicates state that their products have overcome this difficulty The reagent may be applied alone, or, better, in a mixture with lime-water and common salt, or with inert fillers such as kaolin or asbestos. B Ammonium Phosphate Strong solutions (25 to 35 percent) of monammonium phosphate or diammonium phosphate give good protection. Two or three coats of hot solution should be applied either with a large flat brush or an ordinary paint spray gun The solution should be applied as hot as possible, as this improved penetration, and it should be the aim of the operator to apply 4 lbs of reagent, i e , one gallon of 33 percent solution to every 100 square feet of surface

Jan 1, 1976