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By M. P. Ristenbatt, E. K. Holland-Moritz, K. Metzger

A new post-disaster signalling system for the Bureau o Mines, using through-the-earth EM propagation, was successfully field-tested in the Lake Lynn test mine. Successful detection at an estimated input SNR of -30dB was accomplished using a coherent integration time of 4.46 minutes. The transmitted waveform consisted of a repeating pseudonoise maximal length sequence phase modulating a 1950Hz carrier. The receiver used a sliding-window matched filter, optimal for signal known exactly except for phase and starting time, implemented via a special purpose processor. Parallel processing permits adaptive signalling, where the detection (integration) time is determined by the actual input SNR encountered. This field test demonstrates a trapped miner detection system that is about 36dB more sensitive than a current pulsed system. This increased sensitivity permits some desired combination of increased range, shorter detection time, and reduced transmitter power or antenna-size. The combination of pulse-compression-type-signal, coherent integration, parallel-processing, and output peak-detection algorithms permit implemention of an ultra-reliable detection system. The same combination is compatible with digital Pulse Position Modulation and Emitter position location strategies.

Jan 12, 1983

By G. M. Kintz

The data in this circular were taken from publications of the United States Bureau of Mines and published annual reports of the Wyoming State Inspector of Coal Mines. The tables included are complete only' with regard to major disasters; the Bureau of Mines considers a major disaster one in which 5 or more men are killed. However, minor disasters and gas ignitions recorded in these publications are included. It is known that a number of gas ignitions have occurred of which no record is available. This is one of a series of papers by the Bureau of Mines giving by States available data regarding coal-mine explosions. This information is published in condensed form in the belief that it may be of vale to mine operators in preventing future coal-mine explosions.

Jan 1, 1934

By F. L. Wideman

Output of ore and waste from metal and nonmetal mines in the United States continued an upward trend and established a new high. The tonnage of ore handled increased 6 percent over that moved in 1964 and the tonnage of waste rose almost 10 percent. Earth moving by these two activities exceeded 3.2 billion tons, an increase of 7 percent over the 1964 total. Crude material from which metal or nonmetal products were derived continued to be about 75 percent of the total material handled. In 1965, surface mining methods were used to produce about 93 percent of the ore, 99 percent of the waste, and 95 percent of the total material handled. These percentages have remained almost constant since the beginning of this decade.

Jan 1, 1966

By Charles Prasky

This report describes bench-scale studies and pilot-plant development of the Bureau of Mines process for roasting iron ores with a ferrous scrap reductant, such as discarded automobile hulks, to yield artificial magnetite. Quality magnetic concentrates containing about 66 percent iron and 6 percent silica with iron recoveries of over 90 percent were obtained after roasting fine-grained oxidized or nonmagnetic taconite with unburned, sheared automobile hulks in a rotary kiln. The relatively complete oxidation of the lighter gage metal in the automobile during roasting resulted in a metallic byproduct consisting of the unconsumed heavier gage metal scrap. This residual or tailored scrap is potentially useful as heavy melting stock and has more value than the original automobile hulk.

Jan 1, 1970

By W. N. Marchant

The Bureau of Mines improved removal of selenium from zinc smelter acidic gas scrubber effluent by using zinc dust to precipitate soluble selenium prior to lime neutralization. Lime neutralization alone decreased selenium in the waste water from, typically, 6 parts per million to 2 parts per million, whereas the use of zinc dust precipitant gave an effluent containing less than 0.1 part per million of selenium. The waste treatment operation first was developed on a laboratory scale and later was successfully tested at a smelter site on a 1-gallon-per-minute basis. During the research a simple and rapid means was developed for determining selenium in waste water; the technique enabled visual semiquantitative selenium determinations that later were confirmed quantitatively by X-ray fluorescence.

Jan 1, 1978

By Howard E. Parkinson

The mine pager phone to public telephone interconnect system permits mine paging telephones to be interconnected with the public phone system, thereby providing emergency and off-hours communications. The system, a push-to-talk, push-to-listen system, is compatible with any mine paging system utilizing dc voltage on the line to enable paging. A tone generator of the proper frequency enables an outside caller to page over mine pager system loudspeakers. A caller inside the mine can make an outgoing call to a preselected, preprogramed number with the use of a proper frequency tone generator. The system includes an automatic hangup timer that restricts the time off-line due to a wrong number or incorrect hangup to 20 seconds and 6 minutes, respectively.

Jan 1, 1974

By Thomas J. Peters

In 1988, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied the 5,640-acre Soda Mountain Wilderness Study Area (OR-011-017), in order to evaluate its identified mineral resources. The study area is located in Jackson County, OR, about 30 miles south-east of Medford. The study area covers most of the south-facing slope of 6,071-ft Soda Mountain. Geologically, the area is underlain by Oligocene to Pliocene basaltic andesite flows and less extensive intrusive rocks of the western Cascade Mountains. In addition, there is a 3/4-mile-diameter area of kaolinized and silicified rhyolite tuff, which appears to have intruded the andesite, and is host to epithermal gold mineralization.

Jan 1, 1989

By C. E. Schmidt

Condensate waters from the Bureau of Mines Synthane process for coal gasification have been investigated by mass spectrometric methods to determine the organic contaminants. Waters from the gasification of six coals were extracted with methylene chloride, yielding 0.6 to 2.4 weight-percent extractable material. Using high-resolution mass spectrometry (HRMS), combined gas chromatography-mass spectrometry (GC-MS), and low-voltage mass spectrometry, 60 to 80 percent of the extract was found to be phenolic. About 20 organic contaminants have been identified and are present in the condensate waters from each coal gasified. The relative distribution of contaminants in the condensate water was nearly the same for the six coals gasified under various conditions; phenolic compounds were the most abundant in all cases.

Jan 1, 1974

By J. E. Meacham

The U.S. Bureau of Mines investigated recovery of manganese from basic oxygen furnace (BOF) steelmaking slags because the slags represent a large potential resource of a metal for which there is no domestic production. BOF slags were leached using fluosilicic acid, a byproduct of the fertilizer industry. Manganese and iron were extracted as soluble manganous and ferrous fluosilicates while the calcium and magnesium remained in the tailings as insoluble fluorides. Treating the pregnant liquor with sodium chloride, precipitated sodium fluosilicate (Na2Sif6) which was recovered as a byproduct. Manganese and iron were precipitated as hydroxide-carbonate salts with the addition of sodium carbonate to the treated liquor. Recoveries for manganese and iron were 73 to 83 and 67 to 70 pet, respectively.

Jan 1, 1991

By Carlton E. Brown

The purpose of this report is to present results of tests on the effectiveness of a spray of water mist, commonly called compressed-air water blast or water blast, in reducing the concentration of dust present in the air shortly after blasting and during mucking of the blasted material. Many observations have been male on the effectiveness of such ,sprays, but published quantitative information on comparative dust concentrations with and without their use, obtained by dust-sampling methods in use in this country, is rare if not absent. Tests conducted in South Africa about 19164/ and more recently in England5/, 6/ have shown that such sprays reduce the dust concentration to very low values within a fen minutes after blasting,

Jan 1, 1938

The REL of 1 mg/m3 for respirable coal mine dust does not assure a zero risk for the development of occupational respiratory diseases among all miners exposed during a full working lifetime. Consequently, a medical screening and surveillance program that includes initial and periodic chest X-rays and spirometric examinations is important for the early detection of disease and the prevention of "material impairment of health or functional capacity" [30 USC 8 11(a)(6)(A)]. The medical screening and surveillance program is also useful for disease surveillance, which includes the tracking trends, the setting of prevention and intervention priorities, and the assessment of prevention and intervention efforts. NIOSH encourages both underground and surface coal miners to participate in the medical screening and surveillance program.

Jan 1, 1997

By Fred N. Kissell, Maurice Deul, T. D. Moore

Methane emission from two surface gob-degasification boreholes was measured by the Bureau of Mines. The investigation took place during mining of a 3,200-foot longwall panel in the Lower Kittanning coalbed in central Pennsylvania. The first hole was 500 feet from the start of mining, and the second hole was 2,200 feet. The first hole went on natural draft as soon as the longwall face passed it. This caused the methane flow in the return entries to drop 75 pct. In the 6 months required to complete the panel, the two holes emitted 69 MMcf of methane in varying percentages of concentration in air. In 3 years, the holes emitted a total of 150 MMcf of methane.

Jan 1, 1976

By J. Roger Loebenstein

Demand for arsenic exceeded supply, and major domestic and foreign producers allocated available supplies to customers for the fourth consecutive year. Major demand for arsenic was about evenly divided between industrial chemicals and agricultural chemicals. Legislation and Government Programs.-Effective April 1, 1981, taxes were collected from companies producing and importing 42 chemicals and petroleum products designated as hazardous, The revenue was used to begin funding of the 5-year, $1.6 billion "superfund" being established under Public Law 96-510, the Comprehensive Environmental Response, Compensation, and Liability Act, designed to help clean up spills of hazardous substances throughout the United States. As hazardous chemicals, arsenic metal and arsenic trioxide were taxed at the rate of $4.45 and $3.41 per short ton, respectively.

Jan 1, 1982

By L. A. Johnson

The Bureau of Mines analyzed three cores from the south Seep Ridge area of the P. R. Spring tar sand deposit of northeastern Utah. Four tar sand zones are indicated in the area. The zones range in average thickness from 13 to 24 ft. The total net thickness of the tar sand in the three coreholes ranges from 71 to 112 ft. The tar sand occurs between the depths of 27 and 254 ft. It has good porosity, 25.6 pct of bulk volume; high permeability before and after oil extraction, 819 and 2,218 md, respectively; but a relatively low oil saturation, 36.5 pct of pore volume. Gravity of the oil ranges from 8.20 to 16.5° API.

Jan 1, 1975

By C. M. Frost

Crude shale oil produced by gas combustion retorting of Green River oil shale was hydrocracked over a cobalt molybdate catalyst at operating pressures of 500, 1,000, 1,500, and 3,000 psig, an operating temperature of 8900 F, and a liquid hourly space velocity of 1.0. Hydrogen feed rate was maintained at 6,000 scf/bbl. The volume-percent yields of total liquid product were directly proportional to the operating pressure. Weight-percent conversion and volume-percent yields of gasoline were directly proportional to the log of the operating pressure. Catalyst deposit percentages were inversely proportional to the log of the operating pressure. Nitrogen and sulfur removal rates as well as saturation of the liquid products increased as the operating pressure was increased.

Jan 1, 1973

By James S. Browning

The Bureau of Mines conducted laboratory and small-scale continuous tests of kyanite ore from Georgia to determine the technical feasibility of recovering commercial-grade kyanite concentrates by flotation. The research indicated that combinations of sulfuric acid and petroleum sulfonate may be used effectively for flotation of kyanite from quartzite-kyanite ore. Over 87 percent of the kyanite was recovered in a concentrate analyzing 55.8 percent A1203 and 5.3 percent acid-soluble Fe203. Subsequent treatment of the flotation concentrate by high-intensity wet magnetic separation reduced the acid-soluble Fe203 to 0.8 percent and increased the alumina content to 57.6 percent, with a recovery of 82.7 percent of the total alumina in the ore.

Jan 1, 1970

By G. F. Friel

A series of experiments in the U.S. Bureau of Mines Safety Research Coal Mine at the Pittsburgh Research Center evaluated the effects of crosscuts on the travel time of carbon monoxide (CO) along an entry to improve the accuracy of a mine-fire locator program. Three entries, ten single crosscuts, and three double crosscuts were instrumented with CO sensors. One-percent CO in nitrogen was released and monitored as it traveled the entries. In addition to dispersion of CO at the front of the CO wave, CO was entrained from the entry into the crosscuts. It was determined for an entry and single-crosscut configuration that the measured travel time for a concentration change of 5 ppm was 27% greater than the predicted time based upon entry volume only, but 13% less than the predicted time based upon entry and crosscut volumes. For an entry and double-crosscut configuration, the measured travel time for the same concentration change was 25% greater than the predicted time based upon entry volume only, but 10% less than the predicted time based upon entry and crosscut volumes. An effective dispersion coefficient for CO dispersion along one of the entries was estimated to be 1.5 m2/ s.

Jan 1, 2010

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

C 6 Automatic Elevator Control Systems An automatic elevator control system, consisting of position sensing devices and a control unit, can be used to control an emergency mine hoist. While automatic elevator control systems are assembled from standard components, they are typically custom designed to suit a given customer's application. Various manufacturers contacted indicated that the price range, less installation, for a simple two-stop control system begins at approximately $2500 and can increase depending upon the type of components used, shaft depth, the type of mechanical drive used, and the maximum operating speed A partial list of elevator control manufacturers follows. They should be contacted for further details. Marshall Elevator Company Pittsburgh, P A 412 -431 -1340 Armor Elevator Company, Inc. Louisville, KY 502-361 -7181

Jan 1, 1976

By C. W. Smith

The Bureau of Mines conducted laboratory beneficiation tests on four samples of waste. granite sludge to devise a method of recovering silicon carbide (SiC). Froth flotation using creosote as a collector in an alkaline circuit resulted in concentrates containing over 91 pct SiC from each of the samples. Recoveries ranged from 43.1 to 86.6 pct. Single-stage flotation of sample A using a column flotation cell produced a concentrate containing 92.0 pct SiC with a recovery of 71.4 pct. Flotation using petroleum sulfonate as a collector in an acid circuit resulted in a concentrate containing 95 pct SiC from one of the waste granite products with a recovery of 97.5 pct .?

Jan 1, 1987

By P. M. Brown

The Bureau of Mines is investigating a dewatering technique for coal-clay waste that uses a flocculant, polyethylene oxide (PEO). This flocculant forms strong stable flocs that can be dewatered on a static screen. A field test unit (FTU) using this technique was operated at approximately 400 gal/min, using a waste stream from the flotation circuit of a coal preparation plant. Consolidated coal-clay material con-taining 55 to 60 pct solids was produced when the flotation circuit slurries of 2.7 to 8 pct solids were treated with 0.1 to 0.3 Ib PEO per ton of solids. The FTU was also operated at 64.5 and 87.5 gal/min using a portion of the underflow slurry from the preparation plant's thickener. Consolidated coal-clay material containing 55 to 60 pct solids was produced when the thickener underflow slurries of 19 to 24 pct solids were treated with 0.08 to 0.2 Ib PEO per ton of solids. PED-treated materials continued to dewater when placed in a pit.

Jan 1, 1983