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By John Ward Smith

An analytical method developed by the Bureau of Mines to determine dawsonite, nahcolite, and nondawsonite alumina (called excess alumina) extractable from Green River Formation oil shales is presented. The method requires water extraction of nahcolite followed by HCI-extraction of dawsonite and an unidentified mineral yielding excess alumina from the water-leached residue. Instrumental determination of sodium in the water extract and sodium and aluminum in the HCI extract measures the sample's content of the minerals. Detailed evaluation shows the method to be adequately specific, precise, and reproducible and free from uncorrectable interferences. The method's results define precisely the production of sodium carbonates and alumina possible from a sample of oil shale and the interval it represents. Shale-oil yields, nahcolite contents, and yields of extractable alumina determined on 83 samples representing an 821-foot section of dawsonite-nahcolite-bearing shale from .Colorado Corehole No.3, drilled in the north part of Colorado's Piceance Creek Basin, are presented. These samples resulted in nahcolite contents to 53.3 percent, oil yields to 48.3 gallons per ton, and alumina yields to 5.80 percent. Use of these data to evaluate the production potential of a section of the formation are suggested.

Jan 1, 1969

By James P. Ulery

A Bureau of Mines geologic study of Pennsylvanian and Permian coalbeds in southwestern Pennsylvania was undertaken to determine the effects of coalbed geology and petrology on in situ coalbed gas contents. Data were obtained from 18 coreholes from parts of four 7.5 ' quadrangles in southwestern Washington and northwestern Greene Counties, and from a single corehole in Westmoreland County. A total of 88 samples from 24 coalbeds were collected for direct-method testing to determine gas content. The samples were also analyzed for petrographic composition, chemical composition, and vitrinite reflectance values. Corehole information was used to generate isopach maps and geologic cross sections useful in data interpretation. Results of the investigation show that coalbed gas content is related to vitrinite reflectance, but not to petrographic composition. Gas contents are also influenced by other geologic factors such as roof rock lithology and competency, and location with respect to local fold structure.

Jan 1, 1989

By Carla A. Kertis, Alan A. Campoli, Claude A. Goode

This Bureau of Mines study was conducted to obtain a better understanding of the coal mine bump problem and its effect on underground coal mining in the Eastern United States. To accomplish this, information was collected on the geologic conditions, mining techniques, and engineering parameters at five bump-prone mines. Two geologic conditions have been found to cause the occurrence of bumps in the Eastern United States: (1) relatively thick overburden and (2) extremely rigid strata occurring immediately above and below the mine coalbed. Additionally, the probability of bump occurrence is increased by certain mining practices that concentrate stresses during retreat mining, in areas where geologic conditions are conducive to bumps. Mining plans that permit the development of pillar line points or long roof spans that project over gob areas should be avoided because these features may contribute to the occurrence of bumps.

Jan 1, 1987

By R. V. Lundquist, H. Leitch

Two hydrated calcium aluminates , formed by side reactions in the leaching step and desilication step of the lime- soda sinter process , were investigated to better define their influence on alumina recovery . The two calcium aluminates , Caз [ Al ( OH) 6 ]₂ and зCa0.Al½ 03 · ( 8-12 ) H₂ ) , were prepared and identified by chemical and X- ray analysis . The relative proportions of each of these compounds formed in typical leach solutions at several temperatures were determined . The influence of free lime as a promoter of calcium aluminate formation was also investigated . The formation and precipitation from leach liquors of calcium aluminates contributes to the low alumina recoveries in the process . The presence of carbonate ion in the leach solution suppresses calcium aluminate formation and precipitation and results in higher alumina recovery . Hydrated calcium aluminates are formed in the aging of lime - soda sinters in the normal atmosphere .

Jan 1, 1963

By F. E. Armstrong

Tritiated water has been used as a tracer to follow the path of leach liquids as they flow through a copper-mine dump. Semipermeable layers, produced within the dump by compaction and "stratification" of deposized dump material, restrict the vertical movement of water. Knowledge of this restriction would aid in the optimization of the leaching process. The portion of the dump of particular interest was approximately 2,000 feet long, 800 feet wide, and 200 feet high. A total of 94 curies of tritiated water was injected into the dump at the rate of 650 gpm over a period of 39 hours. The leach liquid was sampled at natural surface outflows and through a series of wells, some drilled to the bottom of the dump and others to intermediate levels. More than 3,300 samples were analyzed, most by liquid scintillation counting, but a few hundred by gas counting. Data obtained permitted calculation of flow paths, recycle times, total fluid volume, and estimates of retention times in various portions of the dump.

Jan 1, 1971

By J. T. Schimmel

The purpose of this investigation was to obtain complete information on some of the uses of a 24-inch-diameter auger in the underground mining of pitching anthracite beds. The auger was placed in operation early in 1958 to drive ventilation connections between coal gangways driven by a continuous miner. Although designed to drill rise holes only, it was used also to drill dip holes. The latter holes were drill id from an adjacent gangway to avoid interference between the auger and the continuous miner. These holes established immediate ventilation returns when intersected by the continuous miner. Bureau participation in the project covered 361 working days. The auger was used on 288 shifts, usually one 7-hour shift per day, and drilled 3,246 feet, of which 493 feet were reamed. The longest hole was 87 feet; hence the maximum drilling depth of the machine (rated at 100 feet) was not required. Holes drilled normal to the strike of the bed ranged from 30 to 66 feet deep, averaging 45 feet. The continuous miner drove gangways on 575 shifts. Thus, the auger worked one shift for each two worked by the continuous miner and was used on less than 80 percent of the workdays. The auger drove 24-inch holes 10 times faster than the larger, conventional openings could have been driven by usual mining methods and exceeded the workload for which it was purchased. Augering eliminates exposure to the hazards encountered in driving chute-work by conventional methods and provides adequate circular ventilation openings, which are strong in self support and are adaptable to reaming when required. With alterations, the auger may have limited use as a production machine in thin-bed pitch mining but cannot compete with established methods of thick-bed pitch mining.

Jan 1, 1962

By George C. Branner

This Bureau of Mines report presents information on the origin, collection, movement, and consumption of iron and steel scrap in California and Nevada. As far as practicable, information is presented on a grade basis. The iron and steel scrap industry in California is important from the standpoint of employment, economic essentiality, and dollar value. About 16,000 persons are either directly or indirectly employed on a full- or part- time basis in the collection, preparation, and sale of iron and steel scrap in California; in 1957 about 70 percent of the tonnage of products of California steel mills, valued at $271 million, was derived from scrap; the value of scrap in 1957 ($117 million) is about $10 million greater than the value of portland cement produced in California that year. The iron and steel scrap industry in Nevada is small.

Jan 1, 1960

By B. H. Eccleston

Experimental data were obtained from two medium-duty diesel engines derated to qualify for use in underground mines. Gaseous and particulate emissions from these engines were measured and results provide information on the effect of exhaust treatment devices on the emissions. The devices in the study were a catalyst, a particulate trap, and an exhaust gas cooler of the water scrubber type. Emission levels of carbon monoxide and hydrocarbons were observed to be very low in comparison with emission levels of comparable engines in full-rated operation. Oxides of nitrogen and benzo(a)pyrene content of the exhaust also were found to be somewhat low in comparison with previous findings. For particulate reduction, the combination of a particulate trap and a scrubber was observed to be the most effective combination tried; in some cases, over 60 pct particulate reduction was effected by the trap-scrubber combination.

Jan 1, 1981

By B. Dimitriades

Experimental work has been done to refine and to confirm an analytical procedure by which gas-liquid chromatographic (GLC) spectra are interpreted from retention time data alone. The rationale of this spectra interpretation technique involves whether or not a given peak invariably represents the same component or component mixture; if not, what factors influence changes in peak identifications. To answer these questions, peak-identification procedures, based mainly on the use of subtractive columns, were developed and applied to interpret GLC spectra of several exhaust (and fuel) samples.

Jan 1, 1972

By Susan M. Moore

According to the Mine Safety and Health Administration (MSHA) injury database, 227 knee injuries were reported in underground coal mining in 2007 [ 1]. Low-seam coal mines are those with extremely low working heights (<42?). Gallagher et. al [2] found that the average cost per knee injury in low-seam coal operations was $13,121.29. Thus, it can be estimated that the financial burden of knee injuries was nearly three million dollars in 2007. Pressure applied to the knee while kneeling and crawling is likely a risk factor. Typically, mine workers utilize kneepads to better distribute the pressures at the knee; however, their ability to reduce the stresses at the knee is unknown. The objective of this study was to determine the pressure applied to the knee during static postures used in low-seam mining while not wearing kneepads and while wearing two kneepads commonly used in the industry (one articulated and one non-articulated).

Jan 1, 2009

Determine the minimum waterflow rate needed for effective control of dust produced by cutting machines used to mine water-soluble ores. Approach Conventional wet-bar cutting techniques were studied to evaluate their dust control performance, and the optimum water flow needed for dust suppression was determined. Wet-bar type cutting techniques are used to help control mine dust by keeping the cutting chain wet. As the chain cuts the kerf, it dampens the dust produced by the cutting action at the point of generation. The Bureau, under contract, evaluated three basic wet-bar techniques, as shown in the diagram: water-trickle system A uses a gravity-feed or low-pressure (less than 50 psi) pump to send water through the bar and to discharge it at the bar tip. Water-spray system B uses a low-pressure spray nozzle located at the front of the cutter head. For protection the nozzle can be located within the cutter

Jan 1, 1982

By M. O. Magnuson

As part of an experiment in the restoration of lands strip-mined for coal, revegetation studies were conducted at three backfilled strip-mine sites in north-central Pennsylvania. The sites were subdivided into plots that were given varying amounts of lime and fertilizer. In tests conducted cooperatively with State and Federal agronomy experts, the plots were then planted with a variety of trees, shrubs, and grass-legume mixtures. Initial tree and shrub survival was not appreciably affected by lime and fertilizer applications where the spoil pH was above 4.5. Of 14 species of trees and shrubs tested, Norway spruce, black locust, Japanese larch, pitch pine, and white pine were the hardiest. The ground-cover percentage of grass-legume mixtures in the second growing season was substantially increased by using lime and fertilizer. Mixtures comprised partly of fescue were the most satisfactory.

Jan 1, 1968

By Ralph B. Adair

The Bureau of Mines conducted laboratory batch and small-scale continuous tests on samples of silt from the Nolichucky Reservoir near Greeneville, Tenn., to develop a process for the recovery of commercial-grade muscovite concentrates. Using a combination of Humphreys spirals for preconcentration followed by cationic flotation, 94.5 percent of the muscovite was recovered in a product containing 96.5 percent muscovite.

Jan 1, 1971

By Fun-Den Wang

Finite-element structural analyses were performed to determine the stress distribution and displacements around a single rectangular coal mine opening in a multilayered rock system. The effects of changes in mechanical properties of roof and coal layers, roof layer and mine opening geometry, horizontal-to-vertical load ratio, and structural geologic features on the stress distribution about the opening were studied. Variability in the stiffness and relative thickness of the immediate roof layers can produce a considerable difference in the stress distribution about the opening as compared with that of a homogeneous material. Changes in opening width and horizontal-to-vertical load ratio have different effects on the stress distribution about the opening depending on the composition of the roof layers. In general, where a stiff layer exists in the roof at the surface of the opening, the stresses are higher in the roof and ribs around the opening. Horizontal changes in facies in the roof layers produced by structural geologic features can also greatly alter the stress distribution about the opening compared with the simple layered cases.

Jan 1, 1974

Develop a simple and practical technique to measure in situ rock mass properties for realistic design and stability evaluation of underground structures. Background The Bureau of Mines has developed basic principles and techniques to determine in situ rock mass properties including Poisson&apos;s ratio, deformation modulus, and yield and failure strengths. An instrumentation package consisting of three pressure cells is installed in a single drill hole. Cell pressure response data are acquired and used to calculate and determine the rock mass properties. How It Works A test hole of BX size (approximately 5.7 cm) or larger is drilled to the approximate depth of the measuring point. The last portion of the test hole is drilled with precision bits to EX size (approximately 3.8 cm). The instrumentation package, which consists of one 3.8-cm-diameter cylindrical pressure cell (CPC) and two 5.7-cm-diameter cement-capsulated, flat borehole pressure cells (BPC&apos;s), is then installed. A complete history of cell response to changing strata loads is acquired on a continuous basis with a chart-type hydraulic pressure recorder. From these cell pressure data, Poisson&apos;s ratios, deformation moduli, and yield and failure strengths are calculated and determined.

Jan 1, 1990

By Theodore Christos

The Bureau of Mines sponsored an investigation of the thermal oxidative degradation characteristics of certain solvents and hydraulic fluids used in underground mining operations. The following halogenated solvents were studied in view of their usefulness and their flame retardant property: tetrachloroethylene, C12C = CC12; 1, 1, 2-trichloroethane, CIH2CCHC12: and trichloroethylene, C12C = CHC1. The hydraulic fluids studied were representative of five groups approved by the Mine Safety and Health Administration for underground operation, namely: glycol-water solutions, mineral oil-water emulsions, synthetics other than phosphate esters, synthetic phosphate esters, and mixtures of phosphate esters with mineral oils and other ingredients. It was observed that the partially halogenated solvents present a greater potential toxic hazard than the fully halogenated materials, due not only to the easy production of hydrogen chloride but also to their ease of oxidation leading to the formation of phosgene and carbon monoxide. The pure phosphate esters exhibited the best thermal oxidative stability of the five groups of hydraulic fluids tested. A fluid containing phosphate esters mixed with mineral oils and other unidentified ingredients appeared to be the most hazardous On the basis that it produced very toxic acrolein and phosphine.

Jan 1, 1980

By John Nagy

This circular has been prepared for the guidance of safety engineers, shot firers, and coal-mine inspectors concerning multiple blasting with short-delay (millisecond-delay) detonators. These special precautions are suggested in addition to those normally followed in blasting, as outlined in the Federal Mine Safety Codes 5 6/ and in Miners&apos; Circular 58.7/ INTRODUCTION The use of short-delay blasting has been proposed for promoting safety and increasing the rate of production in coal mining. Ideally, short-delay blasting, as compared with equivalent single-shot blasting, reduces exposure of the shot firer to dust, fumes, and weakened roof; as compared with equivalent simultaneous blasting, it reduces roof disturbance.

Jan 1, 1959

By L. C. IlsLey

As part of its work for the improvement of safety conditions in mines , the Bureau of Mines has undertaken to establish a list of permissible storage - battery locomotives for use in gaseous mines , and , to this end , has issued Schedule 15 , "Procedure for Establishing a List of Permissible Storage -Battery Locomotives for Use in Gaseous Mines . " Up to the present time , two approvals * have been issued under this Schedule , and considerable testing work done on four other applications which have been made for approval . Prior to the publication of Schedule 15 , the Bureau conducted both field and laboratory investigations to determine the hazard from the batteries used in mine locomotives . ** These investigations indicated that the safety of the locomotive would depend largely on proper care of the battery , also on the use of a battery as mechanically rugged as possible . For this reason the Bureau staff , in testing locomotives submitted for approval , considered it advisable to subject the batteries to a jarring or bumping test to prove their adequacy as regards mechanical endurance and ruggedness . These tests on the batteries of the locomotives are described below.

May 1, 1922

By S. J. Davenport

[The tremendous increase in mine mechanization since 1929 has increased markedly the application of electric power in and about the coal mines of the United States. Cutting, drilling, and leading machines have replaced hand-mining methods in nary mines. As a result, expansion of the gathering haulage has necessitated introduction of extensive feeder, trolley, grid other power wires. (1)3/ In spite of this vast mechanization the fatality rate from electric shock has been on the decline. However, there are still too many accidents, and efforts to eliminate electrical hazards cannot be relaxed. It is hoped that an acquaintance with the physiological aspects of electrical accidents will make workers end management aware of the lurking dangers of this very common and extremely dangerous form of energy.]

Jan 1, 1951

By D. D. Bolstad

The Bureau of Mines has developed procedures for sampling the geometry of fractures in underground coal mines. Stratified cluster sampling and the unit area concept are applied to the collection of fracture orientation data. The use of unit area mapping, stratification, and site delineation is made to assure collection of representative data. The procedures developed here help to isolate sources of variability in the fracture patterns.

Jan 1, 1973