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By T. H. Dubaniewicz, J. E. Chilton

Fiber-optic technology is progressing rapidly, including the development of fiber-optic sensors for many applications. These sensors have the advantages of high sensitivity, light weight, small size, high bandwidth, and freedom from electromagnetic influences. The U.S. Bureau of Mines is investigating the use of fiber-optic technology to monitor mine atmospheres. This report describes a methane monitor based on differential absorption of infrared light. The monitor can detect methane concentrations as low as 0.2 vol pct as far away as 2 km via fiber-optic cable. The upper range is 100 vol pct methane. Since the system requires no electrical power within the mine, it is intrinsically safe.

Jan 1, 1992

By H. C. Ko

Heats of solution of calcium carbon-ate (calcite) and calcium oxide in hydrochloric acid were determined by solution calorimetry. Combination of these two heats yields a value of 42.643±0.024 kcal/mole for the enthalpy of calcination of calcite at 298.15 K. Literature data on ?H°298.15 of calcination of calcite were reviewed and compared. Thermodynamic properties for the calcination process were calculated from 298.15 to 1,500 K using Gibbs energy functions. This research was undertaken by the Bureau of Mines as an effort to provide thermodynamic data for the advancement of minerals technology, energy conservation, and environmental preservation.

Jan 1, 1982

By George S. Rice

"The successful use of the gas mask by the American Army it France in combatting the poisonous gases of German .shells caused many Army men to feel that the as masks were proof against any kind of gas which might be encountered. The result has been that from time to time there have been reported in the press, deaths of former army men through using their masks to enter various kinds of gases such as illuminating gas, gasoline vapor, and the gaseous atmospheres produced by mine fire. Such a case has just been reported from a mine, in Copperopolis, California, where a former Army man lost his life in descending a mine shaft filled with the fumes of a mine fire. Another man who, in attempting to rescue him, merely used a dust respirator, lost his life also.While the American type of the Army gas mask was developed by the Bureau of Mines for the War Department, and since the war a section of the Bureau's in¬vestigative force has been developing industrial gas masks for certain specificgases, the Bureau has repeatedly called to the attention of the public the fact that such masks have serious limitations and in no case should a gas mask be used in underground workings for the reason that there may be an insufficient amount of oxygen to breathe, (and the gas mask does not supply oxygen) or there may be present carbon monoxide, which the Army mask will not remove, and there always is some carbon monoxide produced by a mine fire or by a coal-mine explosion, or by a blast of dynamite or other explosive.It is true that the Bureau has been developing a mask which may take care of a small percentage of carbon monoxide, that is, one per cent and under, but in mine fires and after explosions, there may be, and frequently is, a much larger percentage of carbon monoxide in the mine atmosphere. Masks such as these, for small percentages of carbon monoxide and associated gases are for use in connection with industrial surface plants, as for example, on the top of a blast furnace or around gas producers in the open air."

Oct 1, 1920

By J. C. Franklin

An experiment was conducted by the U.S. Bureau of Mines and the Canada Centre for Mineral and Energy Technology (CANMET) to measure the emanation rate of radon from cemented unclassified mill tailings in two dewatered stopes of a uranium mine at Elliot Lake, Ontario, Canada. The radon was monitored upstream and downstream and in both stopes to determine the concentration in the stopes and the amount exhausted from both stopes. The emanation rate was determined to be 0.55 pCi/cm2 sec-1 from the mill tailings, which is approximately 1,000 times higher than the average flux in the mine before backfilling.

Jan 1, 1982

Objective To reduce equipment operator exposure to respirable dust in enclosed cabs by examining the effectiveness of retrofitting air pressurization and filtration systems on existing cabs. Background Many types of heavy equipment are used in mining, construction, and agriculture. Most have enclosed cabs to protect the equipment operator from excessive dust and noise exposure. When the equipment is new, controls are normally implemented into the cab to keep these exposures at acceptable levels. However, as this equipment becomes older, many components of the enclosure deteriorate, such as gaskets and seals. This causes the effectiveness of the enclosed cab to be greatly reduced. Once this occurs, the equipment operator's dust exposure can increase to hazardous levels. In surface mining operations, elevated exposures to crystalline silica have caused an excessive incidence of silicosis. Approach A cooperative research study with a mining operation and a cab filtration company was conducted to evaluate the effectiveness of retrofitting an older surface drill with two controls to lower the drill operator's respirable dust exposure. These two controls were: (1) A good air filtering and pressurization system to ensure that clean air was delivered into the enclosed cab. Ideally, the incoming air filter should be 99% efficient in removing particles with an aero- dynamic diameter of 0.3 pm or greater from the airflow. (2) Sufficiently sealing the cab to develop a positive static pres- sure and ensure that dust was not leaking into the cab. This was done by plugging all holes and cracks and maintaining good gaskets and seals. To prevent wind from forcing contaminated air through holes in the cab, the cab's static pressure must be greater than the wind's velocity pressure. During the course of this research, it was found that a floor heater fan used in the drill during the winter months greatly increased the operator’s Respirable dust exposure. Problem Identification Four days of background dust levels were measured as a baseline for this research. These baseline measurements were taken in May 2000 when air temperatures ranged from 60° to 70° F. When this was completed, the two controls were implemented. The first control was to install an improved air filtering and pressurization system on the enclosed cab. This was composed of a two-stage prefilter, a blower, then the respirator-medium secondary filter. Since the secondary filter was on the positive side of the fan, all air delivered into the enclosed cab had to pass through this secondary filter. After the filtering system was installed, the cab was pressurized to a static pressure of0.01 inches of water (w.g.), which is still very minimal. The second control was to seal the cab. New door gaskets were installed, and all cracks and holes in the shell of the enclosure were plugged. This increased the cab pressurization to approximately 0.1 inches w.g.

Mar 1, 2001

The Bureau of Mines believes that all coal mines are potentially gassy; for the purpose of administration in the prevention of explosions and fires, the Bureau recommends: That any coal mine wherein methane or other combustible gas can be detected in amounts as much as 0.27 of 1 percent or more by frequent systematic searches shall be classified as a gassy mine. Permissible methane-indicating detectors such as are given in I.C. 7110 or subsequent lists of Bureau approved methane-indicating detectors, or conventional methods of sampling and analysis of required accuracy may be used. The concentration referred to in the decision is percent by volume.

Jan 1, 1941

By Rudolf E. Greuer, Linneas W. Laage, Xinton Chang

The program MFIRE consists of four files MFIRE0 EXE, MFIRE1 EXE, MFIRE2 EXE, and MFIRE BAT The batch file, MFIRE BAT, controls the operation and cooperation of the three executable pro¬gram files and the output Networks of up to 500 air¬ways and 350 junctions can be modeled in the PC version of MFIRE Larger data sets can be accommodated by increasing array dimensions and compiling the program again. Input for MFIRE is in the form of a data file The data file contains fines of numerical data describing the physical mine, the ventilation parameters present, the fans, and the proposed thermal or mechanical disturbances

Jan 1, 1990

By Gary L. Mowrey, William D. Monaghan, George F. Persetic, Gregory M. Molinda

Ground penetrating radar (GPR) has been investigated by the U.S. Bureau of Mines Pittsburgh Research Center for its potential to determine rod hazards in underground mines. GPR surveys were conducted at four field sites with accompanying ground truth to determine the value of GPR for roof hazard detection. The resolution of the current systems allows detection of gross roof fractures (>6A mm (>0.25 in) zone) or rider beds in coal measure roof. Data quality is not yet sufficient to detect small bed separations or subtle lithologics changes in the roof. Differences in data quality are discussed, as well as suggestion for collecting improved data.

Jan 1, 1996

By E. W. Dean, W. A. Jacobs

"The petroleum division of the Bureau of Mines in its laboratory investigations, has had occasions to develop a number of types of electrical heating equipment. It was found that electric heaters could be used to particular advantage in the standard distillation test for gasoline. (Dean, E.W., Motor Gasoline, Properties, Laboratory Methods of Testing and Practical Specifications, Bureau of Mines Technical raper 214, 1919, 33 pages.) In order to assist in rendering this type of heater available for general use, a description of the apparatus developed by the Bureau was published. (Dean, E.W., A convenient electric heater for use in the analytical distillation of gasoline,. Jour. Ind, and Eng. Chem., Vol.10, 1918, page 823.) Shortly after the article was printed a chemical supply house undertook the manufacture of an electric heater suitable for gasoline distillation. A preliminary model was examined and tested by the Bureau and modifications were suggested that were incorporated in the type of heater that was finally marketed.Description of the Bureau of Mines-heater: The electric heater developed by the Bureau has an inverted conical resistance Plament surrounded by a layer of heat-insulating material and mounted in a metal case having a top of hard asbestos (Transite) board. The resistance element is a helix of nickel-chromium alloy wire held by a molded core of alundum. The Bureau heaters are generally of about 330 watts capacity and are used with stock types of regulating rheostats capable of reducing the effective wattage to about 43 the full-load maximum."

Jun 1, 1920

By J. W. Thompson

ORE CONCENTRATION PROCESS-PATENT OIL FLOTATION PROCESS. The invention of the patent issued to Sullman, Picard & Ballot November 6, 1906 (United States Letters Patent No. 835120), is based upon the discovery of an wholly unexplained phenomenon arising from the agitation of ore pulp containing oil and air in certain proportions. This was a discovery in an art in which it was well known that the elements of oil, air, and agitation possessed certain characteristics and produced certain results. As early as 1860 a British patent first suggested the use of oil in water concentration of ores by pointing out the affinity which oils have for metallic sub- stances in preference to gangue. Subsequently many patentees employed the known affinity of oil for metal in ore concentration proc- esses by using oil in proportions varying from 2 per cent to 300 per cent of the ore and recovering the oil-coated metal particles by causing them to rise to the top or sink to the bottom of the pulp. In these processes the agitation was either gentle or thorough but never great, and though always employed to produce thorough oiling of the metal it was used in different degrees for the sole pur- pose of causing the metal particles to rise or sink. In the prior art the oil was used for its known selective affinity for metal, agitation was em- ployed to mix the oil with the metal, and air was introduced to supple- ment the buoyancy of oil in raising oil-coated metal particles to the surface. To this extent had the art of oil flotation advanced when the patentee entered it, having reached the commercial stage in only two processes, representing respectively metal-flotation and metal-sinking processes, and having reached the stage of success in none. In the line of experiments by the patentee when the proportion of oil to ore was reduced to 1.5 per cent a "float" appeared; at 1.04 per cent still more "float" appeared; at 0.32 per cent the "float" again vastly in- creased; at 0.1 per cent the "float" again vastly increased. It thus developed that in using oil at 0.1 per cent or even at 0.05 per cent of the ore and after violently agitating the pulp from 24 to 10 minutes, there arose to the surface when the pulp was brought to rest, a thick froth or foam of oil-coated air bubbles carrying oil-coated metal particles to the extent of about 90 per cent of the metal con- tent, the foam being sufficiently stable to permit removal and metal recoveries. This was a new result based upon phenomenon then unknown and still unexplained and constituted discovery and promised a change in the art of oil flotation from laboratory experi- ments and mill failures to commercial success. The patent referred to covering the points mentioned has been sustained by the District and the Circuit Courts of Appeals and by the Supreme Court. Miami Copper Co. v. Mineral Separation, 244 Federal, 752, pp. 754-757. ORE CONCENTRATION PROCESS-OIL FLOTATION-INFRINGEMENT. The Miami Copper Co. in its process of concentrating ores by the oil flotation process used three distinct processes that were either the processes included and covered by the Sullman, Picard & Ballot patent or their fair equivalent and which were clearly an infringe- ment of the patent, and the company can not escape liability for such infringement by taking an additional step, although such additional step if taken alone would not constitute an infringement of the Sullman, Picard & Ballot patent. Miami Copper Co. v. Mineral Separation, 244 Federal, 752, p. 768. ORE CONCENTRATION PROCESS-VALIDITY OF GREENWAY PATENT. The patent issued to H. Greenway, June 9, 1914 (Letters Patent No. 1999699), is valid. The process disclosed in this patent was a substantial departure from processes of the prior art. The heating of water is a matter of large moment and the use of acids is a matter of constant and considerable expense. By wholly dispensing with both by the use of a minute quantity of hydroxy compounds, the patentee has disclosed an original and novel plan which has broad- ened and made more simple the agitation process of air flotation. The novelty and inventive character of Greenway's discovery is patentable.

Jan 1, 1918

By Charles Seitz

The Bureau of Mines has modified its parts-per-billion helium-4 analyzer to improve the analytical capabilities of the instrument. The modifications resulted in the following improvements: (1) The analytical precision of the instrument for 10 consecutive analyses was improved to ±1 ppb at the 5,000-ppb helium-4 level, (2) the helium-4 sensitivity was increased almost tenfold, and (3) the minimum detectable limit for helium-4 was improved to 0.5 ppb. The modifications made to improve the instrument included replacing the ion-source control circuit with a direct-current solid-state design, controlling the temperature of the ion source, stabilizing and reducing the pumping rate of the vacuum system, and optimizing peak integration.

Jan 1, 1986

By P. W. Jeran, M. C. Irani, Maurice Deul

This Bureau of Mines survey of methane emissions indicates that total daily emissions have declined from 227 MM ft3 in 1971 to 214.7 MM ft3 in 1973. The highest average daily emissions in million cubic feet per day observed in U.S. bituminous coal mines were, in decreasing order, Monongalia County, W. Va. , 40.7 ; Marion County, W. Va. , 23.1 ; Buchanan County, Va. , 22.1; Washington County, Pa., 12.4; Greene County, Pa., 11.7; McDowell County, W. Va. , 11.4; Cambria County, Pa., 9.8; Jefferson County, Ala. , 9.5; Wyoming County, W. Va., 6.0; Marshall County, W. Va., 4.8; and Indiana County, Pa., 4.8.

Jan 1, 1973

By Richard H. Singleton

Native asphalt was produced in 1980 by six companies in four States. Leading States were Texas and Utah. Output decreased 22% in 1980 to 1.25 million tons while value decreased 2% to $25.0 million. Bituminous limestone was produced by Whites Uvalde Mines and by Uvalde Rock Asphalt Co. in Uvalde County, Tex.; by Southern Stone Co. in Colbert, Ala.; and by Barton County Rock Asphalt Co. in Barton County, Mo. The product was used mainly in street and road repair. Gilsonite was produced by American Gilsonite Co. in Uinta County, Utah, and by Ziegler Chemical and Mineral Corp. in Weber County, Utah. This material was used for purposes other than road repair.

Jan 1, 1981

By Donald A. Wilson

As part of a continuing effort to maximize metal recovery from domestic secondary resources, the Bureau of Mines investigated a process for recovering the metallic portion of scrap alkaline batteries. A pyrometallurgical method for recovering nickel and cadmium from Ni-Cd scrap batteries previously developed on a laboratory scale, was scaled up to 25-and 43-pound charges. The method employed reduction and/or decomposition in a retort using a minimum of 2.5 percent carbon as a reductant. Metallic cadmium was distilled at atmospheric pressure and a minimum of 900° C. Purity of the recovered cadmium was 99.8 percent minimum and the nickel-iron residue contained less than 0.02 percent cadmium.

Jan 1, 1981

By Ted C. Briggs

A removable-jacket distortion apparatus was constructed and used to measure distortion coefficients for two high-pressure vessels. The measured distortion coefficients were used to compute distortion coefficients for volumes VI and (V1+V2) of a 1,000-atmosphere Burnett compressibility apparatus for the temperature range 0° to 75° C. Young?s modulus for Armco 17-4 PH stainless steel, heat treated to condition H1150-M, was computed from experimentally determined distortion coefficients. A 10-to 14-percent correction to the values obtained for Young's modulus may be required because pressure vessel end effects were neglected. The distortion coefficients of the compressibility apparatus are believed to be accurate to about 1 percent.

Jan 1, 1970

By E. G. King

This paper reports measurements of low-temperature heat capacities and entropies at 298.15° K. of two copper ferrites (CUFe204 and CU0.75Fe2.2504). These substances, which occur in copper-smelting slags, have not been sujected to any previous direct thermodynamic investigation. The two copper ferrites are spinel minerals of the variate class. In previous investigations similar data were obtained for 13 other spinel minerals -7 of the normal class and 6 of the variate class. The entropies at 298.15° K. of these minerals have been compiled and revised as necessary in the light of present knowledge regarding structural randomness; entropy values, recommended for use in thermodynamic calculations, are listed.

Jan 1, 1959

By R. V. Ramani, R. Stefanko, G. W. Luxbacher

1 11 THIS IS A DIGITAL COMPUTER SIMULATION OF THE VENTILATION SYSTEM OF A MINE LOCATED IN WASHINGTON COUNTY, PENNSYLVANIA. THE VENTILATION SURVEY ON WHICH THIS SIMULATION IS BASED WAS RUN FROM OCT. 27-30 AND ON NOV. 2, 1976 IN THE ACTIVE PORTION OF THE MINE INBY COMBS SHAFT AND THE INACTIVE PORTION AFCUND AND INBY DONAHOO SHAFT. FOLLOW-UP SURVEYS WERE THEN RUN ON FEB. 18 AND FROM MARCH 7-11, 1977 TO INCLUDE THE MAIN HAULAGE SYSTEM OUTBY THE ACTIVE AREAS OF THE MINE. ALL SURVEY DATA WAS NORMALIZED TO A STANDARD DENSITY OF 0.075 POUNDS/CU.FT. PRIOR TO THE CALCULATION OF INPUT PARAMETERS FOR THIS SIMULATION.

Jan 1, 1977

By V. A. Nieberlein

Problems of design involving the high-temperature characteristics of materials of construction have focused attention on tungsten, the metal with the highest melting point. To study the properties of this metal a method was needed to produce tungsten of high purity easily and consistently. The Bureau of Mines has made tungsten metal in massive form on a laboratory scale by hydrogen reduction of tungsten hexafluoride (WF6). Metal made in this manner had a purity of 99.99 percent or better, with reference to all detectable impurities, including gases. The process tolerated a wide variation in operating conditions, and the results with respect to total impurities as low as 0.01 percent were reproducible.

Jan 1, 1959

By V. Castranova, K. VanDyke

"INTRODUCTION A soluble mediator has been described which is released from activated rabbit leukocytes and induces histamine secretion from rabbit platelets (Barbaro and Zvaifler, 1966; Siraganian and Osler, 1971). This factor has been isolated, characterized and named platelet activating factor, PAF (Bcnveniste et. al., 1972). PAF has since been chemically identified as l-0-alkyl-2-acetyl-sn-glyceryl-3-phosphocholine (Benveniste et. al., 1979; Demopoulous et. al., 1979).PAF is a lipid mediator of broad biological activity. It causes smooth muscle contraction, contraction of lung tissue and decreased FEV 1; while enhancing capillary permeability thus causing edema (Pinkard, 1983). In addition, PAF is a chemoattractant and can lead to inflammation.PAF has been reported to stimulate the release of lysosomal enzymes, leukotriene B,, and lipid metabolites from neutrophils (Smith et. al., 1983; Shaw et. al., 1981; Lin et. al., 1982; O'Flaherty et. al., 1984). The objective of the present investigation was to further characterize PAP-induced stimulation of granulocytes and to develop a bioassay, i.e. chemiluminescence, for screening PAF receptor antagonists and inhibitors of PAP-induced activation of granulocytes. The possible use of the chemiluminescence assay to monitor PAF synthesis by human granulocytes is also described.METHODSBlood was drawn from healthy volunteers into a blood storage bag containing CPD anticoagulant. Granulocytes were partially purified by dextran sedimentation and further purified by centrifugal elutriation as described previously (Jones et. al., 1980). Granulocytes obtained by this procedure were approximately 95 percent pure. The number of granulocytes in this preparation was determined using an electronic cell counter (Coulter Model Z1, Coulter Instrument Co., Hialeah, FL). Isolated granulocytes were used to monitor membrane potential, hydrogen peroxide and superoxide release, oxygen consumption, calcium uptake and, in some cases, chemiluminescence. Studies of PAF receptor antagonists were conducted using neutrophils isolated by density centrifugation. Briefly, blood was layered onto Mono-Poly-Resolving Medium (Flow Laboratories, McLean, VA) and centrifuged at 22 °C and 300 g for 30 min. Neutrophils collected from the second band of this gradient were at least 90 percent pure."

Jan 1, 1989

By J. D. Spagnola

The Bureau of Mines conducted research to obtain comparative data on the extent of reduction of galena and sphalerite with molecular hydrogen and with hydrogen from the thermal cracking of ammonia and methane at various time intervals. Galena reductions of 95 to 99 percent were obtained with H2 and with decomposed NH3 while reductions of 70 to 80 percent were obtained with cracked CH4? Sphalerite reductions of 99 percent were obtained at 1,000° C with Hz and with decomposed NBs; however, complete volatilization of the free zinc from the remaining concentrate and the subsequent recombination of zinc and sulfur vapors resulted. A promoted iron catalyst brought about a decrease of 100° C in the temperature required for complete decomposition of ammonia. It was found that H2S retards NB3 decomposition and that nitrogen retards the reduction of galena by H2? A mixture of N2 and He in about the same ratio as that obtained by the thermal cracking of NBs gave about 15 percent less reduction of galena than was obtained with decomposed NB3; this indicates that a portion of the hydrogen obtained by NBs decomposition is in an active form.

Jan 1, 1965