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By F. D. DeVaney

Metallurgists and coal-washing engineers have used heavy liquids for years in studying the characteristics of ores and coal. By such means true separations can be made between the various specific-gravity increments in the materials examined. To use of heavy liquids has permitted determination of the possible grades of tailings and concentrates by specific-gravity methods on any particular size, and therefore the size to which the ore must be crushed to free the valuable material. The simplicity of float-and-sink separation and the high degree of efficiency attained in the laboratory are factors that commend the method for commercial concentrations.

Jan 1, 1940

By James H. Prout

Roof warning signals were studied in 18 mines covering 5 coal seams. The results of this study confirmed that roof talk must be interpreted for each individual mine after all other conditions are present that indicate danger of roof fall. Characteristics of roof talk pulses were studied to ascertain features used in interpretation. Roof talk pulse decay time was found to be typically 0.1 to 0.5 seconds depending on the dimensions of the entires. Time between roof talk pulses was found to correlate inversely with the degree of danger under certain conditions. Roof talk and machinery noise recordings obtained during this study were used for subjective tests of ear protectors in a simulated coal mine noise environment. These tests required a detailed interpretation of roof talk and yielded results with high statistical power. Results of these tests showed that the use of personal ear protectors in high noise levels does not degrade a miner's ability to discriminate speech and roof talk. A training course was developed to encourage coal miners to pro-tect their hearing by proper use of personal hearing protectors.

Jan 1, 1973

By Michael S. Miller

In 1984, at the request of Bureau of Land Management, the Bureau of Mines studied 8,500 acres of the 20,250-acre Seven Blackfoot Wilderness Study Area (WSA) consisting of all 3,950 acres of MT-024-657A and 4,550 acres of the 4,850 acre MT-024-657B in order to evaluate the mineral resources. Within this report these 8,500 acres are referred to as the study area. Located about 30 miles northwest of Jordan, MT, the study area is underlain by outcrops of Quaternary alluvium and Cretaceous to Paleocene sandstones, shales, clays, and coal. No mines or prospects were found in the study area. Except for some current interest in petroleum and natural gas, there has been no mineral exploration activity in the study area. The study area contains subeconomic clay, placer gold, and coal. Land within the study area is leased or under lease application for oil and gas.

Jan 1, 1986

By F. D. DeVaney

Metallurgists and coal-washing engineers have used heavy liquids for years in studying the characteristics of ores and coal. By such means true separations can be made between the various specific-gravity increments in the materials examined. To use of heavy liquids has permitted determination of the possible grades of tailings and concentrates by specific-gravity methods on any particular size, and therefore the size to which the ore must be crushed to free the valuable material. The simplicity of float-and-sink separation and the high degree of efficiency attained in the laboratory are factors that commend the method for commercial concentrations.

Jan 1, 1940

By Andrew K. C. Wong

Hydraulic transport has been considered as one of the most economical methods in transferring granular materials over relatively long distances. In the natural world, it is used to transport basic material required for the support of life; in industry, it is a method widely adopted for handling materials. But the phenomena of hydraulic transport has not yet been thoroughly understood. As most of them are conditioned by a number of hydraulic and mechanical parameters, of which the basic relationships are not fully known, the traditional approach in relating these parameters to the energy requirement is purely empirical in nature. Empirical formulas, such as that proposed by Durand, (1) only give satisfactory results over a selected range of (particle size)/(pipe diameter) ratios and slurry concentration. When the case is more complicated or when new situations arise, the empirical formulas fail to give good predictory results. In fact, most of these formulas are based upon dimensional analysis, where the underlying physical interaction is not explicitly considered. Apart from the loosely related, non-dimensional groups incorporated in the formulas, there is practically no analytical means for modifying the formula so as to enable it to cope with more complex real physical situations. Although it seems quite remote that a complete rigorous solution to this highly complex problem could be generated in the near future, it is generally recognized (2, 3) that research in this area should be directed to more comprehensive studies of the obscure phenomena. In fact, there are a good number of very basic problems such as the effects of gradation and concentration of particles upon

Jan 1, 1972

By Wallace W. Key

The California pesticide industry in 1962 consumed about 30,000 tons of clay, talc, limestone, diatomite, sulfur, and other minerals as fillers (carriers and diluents) in pesticide formulation. This was 10 percent of the U.S. filler requirement for pesticides. About two- thirds of the California total was supplied by a few local mineral producers; the remainder came mainly from Florida, Georgia, and Wyoming. The objectives of this report are to provide data on quantities, sources, specifications, and market conditions for minerals used as fillers by California pesticide formulators. The study disclosed that specifications for mineral fillers have become more rigid and formulators have become more numerous in recent years. During 1962 over 1,200 firms registered 16,000 pesticide products with the Bureau of Chemistry in California. Factors which will tend to diminish future need for mineral fillers include the trend toward greater use of organic sprays rather than dusts and further development of biological controls, such as the development of sterile insect strains.

Jan 1, 1965

By Wallace W. Key

The California pesticide industry in 1962 consumed about 30,000 tons of clay, talc, limestone, diatomite, sulfur, and other minerals as fillers (carriers and diluents) in pesticide formulation. This was 10 percent of the U.S. filler requirement for pesticides. About two-thirds of the California total was supplied by a few local mineral producers; the remainder came mainly from Florida, Georgia, and Wyoming. The objectives of this report are to provide data on quantities, sources, specifications, and market conditions for minerals used as fillers by California pesticide formulators. The study disclosed that specifications for mineral fillers have become more rigid and formulators have become more numerous in recent years. During 1962 over 1,200 firms registered 16,000 pesticide products with the Bureau of Chemistry in California. Factors which will tend to diminish future need for mineral fillers include the trend toward greater use of organic sprays rather than dusts and further development of biological controls, such as the development of sterile insect strains.

Jan 1, 1965

By E. M. Murphy

Comparative data from ASTM method of test E-162 and large-scale trials in the Experimental Mine show that the flame-spread quality of brattice cloth and other ventilation control materials can effectively be evaluated by either method. Materials having a flame spread index of 25 or less, as determined by the simpler and more economical laboratory test ASTM E-162, do not present a serious fire hazard when used in coal mines.

Jan 1, 1972

By R. E. Collom

The commercial development of petroleum and natural gas fields has reached its present status within 60 years and is still considered by some operators to be "100 per cent wildcatting." 1 A tendency to drill for gusher production, the production that yields big returns in spite of any mechanical defects in drilling methods, has frequently caused drillers to pass by oil-bearing strata of comparatively small yield and actually to overlook rich oil zones in proved fields; in addition, whole fields have been ruined by water because development methods were never carried beyond a hole-in-the-ground stage.2 Unfortunately, the petroleum industry has no mine dumps or tail. ing piles as at metal mines to yield fortunes through later and bette!' methods of treatment. The wasted oil and gas are gone, as are the time, money, and effort wasted in ill-advised or haphazard drilling. Probably as production costs increase less oil will be wasted, but the need to develop and produce from sands of low yield will become more urgent with the increase in consumption of oil and the decrease in supply. Hundreds of wells are producing steadily as the result of months and perhaps years of careful prospecting and of tests during drilling. The Bureau of Mines has studied the testing and drilling methods used at such wells, and presents in this paper a criticism of these methods and suggestions on future work. The term pr08- pecting here means correct identification and measurement of strata as they are exposed by the drill. The term testing means the determination of the kind and amount of fluid stored within the pores or crevices of any stratum exposed in the hole.

Jan 1, 1922

Mining and the related extractive and processing industries are chiefly responsible for America's high standard of living. Enormous quantities of sand and gravel, limestone, copper, iron and a myriad of other mineral commodities are required to sustain our growing nation. However, the mineral deposits, both domestic and foreign, are becoming increasingly difficult to find. Adding substantially to the problem, is the fact that the conditions are worldwide. Foreign politics are increasingly affecting mineral commodity availability. Figure 1, taken from Bureau of Mines, "Status of the Mineral industries 1976" illustrates our dependency (in some cases total) on foreign sources for vital mineral commodities. While few nations are capable of exerting an OPEC-like influence on any one mineral commodity, the threat of cartel arrangements and related control strategies is evident. Nationalization of entire industries, once they become self-sufficient, is also exerting a disruptive influence on a large portion of the mineral industries.

Jan 1, 1977

To improve the air quality in large-opening stone mines by developing better ventilation techniques, including appropriate fan selection in conjunction with air-coursing methods. Background Stone mines are the most common underground large-entry mines in the United States. Data from the Mine Safety and Health Administration (MSHA) for the year 2000 indicate that there were 162 active nonmetal underground mines in the United States, of which 117 were stone mines. Many underground stone mines are drift mines developed from previous quarry operations. Typically, these room-and-pillar mines have entries that are 20 ft or higher and at least 40 ft wide. These large dimensions lead to a very small ventilating pressure loss, even when significant air quantities move through the mine. This is especially true of drift mine operations where ventilating pressure losses of <0.25 in w.g. are common. Underground stone mines with shafts that are<200 ft deep typically have ventilating pressure losses that are <2 in w.g. The pressure losses through these mines are much lower than those of a typical coal mine or deep metal/nonmetal mine. Therefore, the ventilation techniques and principles are quite different. In addition, because of new MSHA regulations that limit the concentration of diesel particulate matter, these mines may need to greatly increase their ventilation airflow. Therefore, large-opening mines need a fan that can move large air quantities and operate at low static pressures. There are three fan types for mine ventilation: centrifugal, axial vane, and propeller. Centrifugal fans are uncommon in underground stone mines as they are often associated with mines requiring the highest of ventilation pressures. Axial vane fans are widely used in all types of mining operations. They are the most common fan type currently found in underground large-opening stone mines. However, they typically do not operate at low static pressures with high efficiency. Propeller fans are currently uncommon in underground stone mines. They are designed for low static pressures and large air quantities at higher efficiency. This fan type best suits the ventilation needs in large-opening stone mines?they produce large air quantities at low pressure losses. Mines with air shafts<100 ft long and at least 12 ft in diameter have fairly low mine static pressures and may also benefit from propeller fans.

Dec 1, 2002

By N. I. Jayaraman

High-pressure shrouded sprays were first tested on a bench to determine air-moving capability and dust collection efficiency. The bench-scale tests indicated that at 500 psi and above, the dust collection efficiency, when sampled downstream of a water eliminator, was about 99 pet for two types of nozzles. However, for the same water flow, the induced airflow was about three times greater in one type than in another. Since the only difference in the nozzles was the spray angle, this factor was important in air movement through a shrouded spray. Full-scale model mine tests were then conducted to determine the reduction in dust concentration behind the line curtain and at the operator position produced by high-pressure sprays in a shroud. The shroud was mounted on top of the boom of a model continuous miner, and high-pressure (greater than 500 psi) sprays were installed inside the shroud. The inlet of dusty air to the shroud was open toward the face and the outlet toward the exhaust line curtain. The high-pressure sprays were compared with conventional sprays mounted at the head of the continuous miner and directing water toward the face. The difference at the operator position (opposite side of brattice) was significant in that, under certain conditions, with conventional sprays an increase in respirable dust concentration of 471 pet was noticed compared with dry operation due to rollback from face. High-pressure shrouded sprays, on the other hand, decreased the dust concentrations at the operator position (opposite side of brattice) by 28.2 pct.

Jan 1, 1981

By J. E. Chilton, T. Mal

Methane monitoring at the mine face is essential to assure a safe work environment in underground coal mines. Machine-mounted methane monitors must be used to continuously monitor methane levels during mining. Monitors used on mining machines must be approved by MSHA and properly maintained to provide protection for workers (30 CFR 75.342). To provide protection the instrument must give accurate readings of current methane levels. Accuracy is maintained by calibrating the instrument with a standard gas at least once every 31 days. Instrument “response time” determines how quickly measurements will change to reflect current concentrations. At present there are no criteria for measuring the response time for a ma-chine-mounted methane monitor while underground. This study examined a procedure for measuring the response time of a machine-mounted methane monitor. Response times were measured using methanometers obtained from three different manufacturers. The effects of the measurement technique and methanometer sensor head design on response time measurements are investigated. Techniques for reducing variation in response time measurements are discussed.

By R. B. Stotelmeyer

Mineral resources, or a potential for their discovery, occur at 34 localities in the Glacier Peak Wilderness and adjacent areas of the north Cascade Range of Washington (see plate). Eighteen of the mineral deposits are in the established Wilderness, four are in or partly in contiguous RARE II (Roadless Area Review and Evaluation) lands recommended by the Forest Service for addition to the Wilderness (A, D and G6031.), three are in adjacent RARE II lands excluded from wilderness consideration, and nine are in nearby roaded areas excluded from the RARE II inventory. Mineral commodities that might be produced from the Wilderness and recommended additions are gold, silver, copper, lead, zinc, molybdenum, arsenic, cadmium, tungsten, cobalt, limestone (marble), pumice, and volcanic cinders. Mineral production from adjacent lands might include most of these commodities, plus antimony, decorative stone, pyrite, silica, and garnet.

Jan 1, 1982

Horizontal holes are drilled underground into coalbeds to control methane flow from ribs and active face areas and to make gas pressure measurements in coalbeds. Gas pressure measurements are made by drilling the same hole incrementally. After each increment, the hole is filled with some type of packers and allowed to reach equilibrium before a gas pressure reading is taken. As the length of hole increases, more packers are required to effect a seal and obtain a reliable pressure measurement. Problems have been encountered in obtaining satisfactory packer seals due to the friable nature of the coalbed. New methods of packing the holes must be used. Therefore, this project was established to evaluate materials and develop a new technique in which a semiliquid and/ or rigid type grout could be placed in the hole to provide satisfactory sealing.

Jan 1, 1972

By L. H. Wullstein

Nitrogenase activity (C2H2 reduction) was found to be associated with the following grasses in the field: Agropyron dasystachyum, Agropyron smithii, Aristida purpurea, Oryzopsis hymenoides and Stipa comata. Uptake of fixed nitrogen was also demonstrated for these grasses. Two unidentified nitrogen fixing bacteria were isolated, one from Stipa comata and one from Aristida purpurea. Cynodon dactylon and Agropyron cristatum were successfully inoculated with the unknown isolate obtained from Stipa comata. The inoculated plants exhibited nitrogenase activity (C2 H2 reduction) whereas uninoculated controls gave negative results.

Jan 1, 1982

By Robert Merritt

Approximately 2,500 tons of low-grade uranium ore were used to conduct a field-scale heap leaching test as well as throe column leach tests. The ore used to construct the field-scale heap leaching test had a grade 0.023% U308 while the ore used fur column leach tests had a grade of 0.027% U308. The ore was crushed to minus 4 in. The field-scale heap was constructed on a clay base with parallel effluent lines running under the heap spaced 7.5 ft apart. The heap was leached for 45 days, drained, washed, and dismantled. Based on residue analysis, approximately 205 tons of ore were leached with a final U308 extraction of 96%. The heap was 17.9 ft in height and leached in a near-vertical pattern down to approximately 1 ft, at which point the leached zone become bell-shaped. Two 8-ft column charges and one 18-ft column charge were leached for 36 and 45 days, respectively. Based on residue analyses, all U308 extractions were greater than 96%. The conclusions generated by the studies showed that (1) flow rates were similar for column leaching and field-scale leaching, (2) final U308 extractions were the same for both types of leaching; however, the deeper ore beds tended to require longer leaching times, and (3) the reagent requirements were reduced with increased bed depth.

Jan 1, 1980

By J. R. Hoskins

This is the final report for Research Contract No. 00101300 (Min. 34) granted by the U.S. Bureau of Mines to the University of Idaho Mining Research Bureau. The research project is entitled "Development of Improved Ventilation Technology for Non-coal Mines and Other Underground Excavations.&apos; The duration of the project was six calendar months, from 16 April to 16 October 1970. The budgeted cost was $34,867.00 of which $31,953.00 was to be furnished by the U.S. Bureau of Mines. The sequence of reporting that follows is to state the objectives as contracted, outline the program of investigation, highlight briefly the important technological factors peculiar to vein-type metal mine ventilation, and describe the normal methods of control. This is followed by the results achieved by the survey, and an itemization of the observed deficiencies in current technology. There follows a section dealing with the adopted Federal Regulations.

Jan 1, 1970

By S. J. Broderick

[Xuge d-mp heap co:lt:.ini9: tilcu?:na3s of tons of cad ~eP~se 2r3 a failiar sight in coal-mininc regior@:. T5ey reprecei~t considergole economic 1083, are very l.u.,si~hC,ly, ?:ld t?ke un m-lch vaL-x3le qace. Cor.sequentl;r thelr remcval i~ geatlyr dezir36, ax2 my ret-sn t?-at c,m be obtained would be er;pecic.llj .a~elconre&apos; t.7 the cod ir.S..r; kry. T?.e vaste rk.t~ri..tl conpl-ises large pieces of slr.t.e, hi~h-2s&apos;. bore c~al., luqs cf cle:., ,ad finer refuse conin,= fro3 the vrtskery, Tilt 1:zshcr:r refilsn contnins sone yood coal. Rig coal and the &apos;better p~lcs of bore ere the zat~rla2.s ~15:;~itiered in this in- vest ig:?.tion. 7% Il~avter frnctions of the w~~sherjr ref;lw aizd tts large 2ieces of slcte ?,".:I rgck contilin 1it:lei ccai-i-bcna.c~o~s caterial ad are vir- tu<dly worthiess nc, rz:. ::atcrin!. for .*=irin,= zct,iv?*teb cCvb~n. 13 the 3irniingh.m district, i13br.12, a-c.ju",P p?rcccn",f the c3sl r?.ir?ed is washed, ,md in tkis c?i.;trict nlz:~c rcfilce ecc;:?:lletcs ~t the r%tg of 1 to 2 million .! tons 2 yew.]

Jan 1, 1941

By N. Kyriazi

The U.S. Bureau of Mines subjected the CSE SR-lOO self-contained self-rescuer (SCSR) approved by the National Institute for Occupational Safety and Health (NIOSH) and the Mine Safety and Health Administration (MSHA) to a series of laboratory treatments designed to simulate various environmental conditions in underground coal mines. The tests were designed to predict the ability of the self-rescuers to withstand those environmental stresses without causing a decrease in wearer protection. The apparatus were heated to 710 C for 48 h, cooled to -450 C for 16 h, vibrated for 9 h, and dropped 1 m on each axis. A critical concern was internal damage to an apparatus, without any obvious external signs, that would cause it to malfunction or seriously degrade its performance. Carbon dioxide (C02) levels in apparatus with combined treatments were higher than in apparatus with individual treatments and untreated apparatus. The higher levels remained within safe limits, however. None of the treatments caused venting of the small oxygen cylinder that provides starter oxygen. Some bottles were found to be empty because of manufacturing defects in the burst disks. This problem was corrected in later models. The heat treatments did make the case ends more difficult to remove and the breathing bag sticky and subsequently more difficult to unfold. An apparatus that was dropped and vibrated had a broken desiccant bag that released some of its contents which compromised the seal of the relief valve. The case was dented from the drops. As with the first-generation self-rescuers, if there is visible damage to the case of the apparatus, the apparatus should be considered to be internally damaged and must be removed from service.

Jan 1, 1990