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Permit visual inspection of underground cavities dam the surface. Approach A closed circuit TV camera and a 35mm still camera are lowered down a borehole, and remotely operated. How It Works A platform holding the cameras, and other equipment is lowered on a graduated cable until the depth of interest is reached. Then a quartz lamp and the TV camera are turned on. The television picture is monitored at the surface and recorded on video tape. Areas of special interest are photographed with a 35mm still camera. These photographs contain more detail than TV images because photographic film is capable of higher resolution than a TV transmission.

Jan 1, 1979

By Robert F. Holub

The Bureau of Mines has made a study of the magnitude of the variations of radon daughter mixtures, with the objective of determining whether these variations reflect the existing physical conditions in uranium mine atmospheres or if they are merely random or systematic errors. To accomplish this, many data have been plotted using a triangular graphing technique which shows that plateout affects RaA more than RaB or RaC, and that it is impossible to find simple correlations between working level ratios, radon daughter mixtures, and age.

Jan 1, 1978

By Travis Q. Lyday

Gold continued to dominate mineral production in the group of volcanic islands and atolls of Melanesia in the southern Pacific Ocean, which comprise the British Commonwealth nation of Fiji. The Fijian mineral sector, however, remained of minor importance in terms of export earnings, Government revenues, and employment to the economy of the country, which was primarily agrarian with sugar as its mainstay. The Vatukoula gold-silver mine on the north side of the main island of Viti Levu remained the largest and most important mining operation, as well as Fiji's only operating metalliferous mine. In October, Western Mining Corp. (Fiji) Ltd. (WMCF), a wholly owned subsidiary of Australian-registered Western Mining Corp. Holdings Ltd., increased its interest in the Vatukoula joint venture from 10% to 20% by exercising its option with Emperor Gold Mining Co. Ltd., also of Australia. The assumption of mine management operations at Vatukoula in 1983, with its attendant influx of additional capital and technological expertise, enabled WMCF to increase both efficiency and output at the mine during 1984. Higher output was obtained owing to an increase in underground ore production, which was partly offset by a reduction in opencut tonnage, as well as to modifications in the recovery circuit. Rate of recovery increased from about 15% to over 82% of the gold contained in the ore and from about 40% to 45% of the contained silver.

Jan 1, 1986

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Jan 1, 2012

It was decided to demonstrate the use of latex as a soil sealant by irrigating three small plots at Lanse coded 03A on the west of Brown's run, 3C on the east of the stream, and SB, an area on the spoil bank. Earlier plans to sprinkle latex on twenty acres of the side were abandoned because of easement difficulties. On the basis of results from laboratory soil columns and small plot experiments at Lanse, Naugatex J-3471 was the latex of choice. The irrigation system consisted of plastic pipe (two inch size) for the main line from the water meter to the irrigation area because of lower price and ease of handling. Because the municipal water supply was limited to 20 gpm, low-volume 14V-LA-TNT Rainbow sprinklers were specified with low angle 20° 3/32 inch nozzles to reduce wind effects. At the expected nozzle pressure of 50 psig, each sprinkler covers a 56 foot diameter area at a delivery rate of 1.64 gpm. Each of the three test areas was covered with twelve sprinklers, six used with water alone as a control area and six used with latex and subsequent water spraying. One-quarterturn inlet valves were positioned on the main lines leading to each area. Flow to the treated and untreated areas was set at 10 gpm by Dole flow control valves in the' main entry lateral to each of the six sprinklers. To avoid the use of dilution tanks, a Moyno pump operated by a 1/2 HP, 1140 rpm 5:1 reducing drive was used to deliver 1/2 gpm 48% latex for mixing with 10 gpm water. A 3500 watt gasoline generator provided power for pump and light. Latex was applied at night to take advantage of the lower evaporation and higher humidity. Neutron gauge access tubes were placed in orthogonal arrangement in the areas that were irrigated, with four tubes in the section that were sprinkled with latex and four tubes in the untreated irrigation section in each of the three locations. Each tube, five and one-half feet long and sealed at one end with a plug welded in place, was inserted five feet into the ground in a cored hole. In each irrigation area, the left section of six sprinklers spread the dilute latex while the right section sprinkled the same amount of water to serve as a control plot. As shown in Figure 7 each sprinkler has a 56-foot sprinkling diameter at 50 psig design water pressure. The sprinklers are 30 feet apart on the laterals and 35 feet apart between the laterals. The access tubes (coded AT on Figure 7) were placed in comparable spots on the two sections of each area, so that four soil moisture measurements on the two sections could be compared. Bouyoucos resistance blocks (BB) were also placed in areas 03A and 3C at one, two and three foot depths, but not on the spoil bank area.

Jan 1, 1972

By Julie Mitchell, Robert King, Len Eros

The Bureau of Mines has studied the Deserado Mine computerized monitoring and control system, located in Rangely, Colorado, to acquire knowledge about the overall costs and benefits of mine monitoring systems. The Deserado system is a complex system monitoring environmental parameters, electrical power, and operation of all mine equipment, and controlling the entire conveyor haul age system. This paper discusses the evaluation of the Deserado monitoring system from initial design through system installation and operation. It also examines the costs, benefits, and performance of the monitoring system.

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

A. 3 Program Description The computer program developed to simulate events in the case of fire in the mine is described in this section The description is divided into three parts. 1. Program Capabilities This part summarizes what inputs can be changed, what outputs can be obtained and demonstrates program flexibility through suggested uses.

Jan 1, 1976

By Fred C. Turin, Kim M. Cornelius

Work in underground coal mines is repetitive and physically demanding. Workers commonly report a wide range of aches and pains. Management at one mine was concerned about increased reporting of aches and pains by roof bolting machine operators. An analysis of roof bolting tasks was conducted at this mine to identify early warning signs of cumulative trauma. Health and safety risk factors were identified and recommendations to reduce cumulative trauma exposure were provided. Recommendations addressed job procedures, equipment design, and worker awareness of risk factors.

By Robert P. Vinson, John C. LaScola, Fred N. Kissell, Edward D. Thimon

The face ventilation measurement method developed by the Bureau of Mines involves releasing a small volume of tracer gas (SF6) on the off-curtain side of the working face at the start of the mining cycle. At the same time, gas bottle samples are taken in the immediate return airway. The gas samples are analyzed, and a curve is drawn of SF6 concentration versus time. From this curve, the percentage of gas removed per time is calculated. A curve showing a high percentage of the tracer gas removed in a short period would represent a well-ventilated face. The face ventilation measurement method was tested in a full-scale mine entry model. Subsequently it was used underground to evaluate the spray-fan ventilation system and in an MSHA test facility to test machine-mounted scrubbers. The method was shown to be a simple and effective way of evaluating face ventilation systems.

Jan 1, 1980

By G. W. Murrie, W. P. Diamond, C. M. McCulloch

It is estimated that more than 1 trillion cubic feet of methane is contained within the coals of the Mary Lee group in Jefferson, eastern Tuscaloosa, and southern Walker Counties, Ala. Most of this methane will be encountered by mining. Coals of the Mary Lee group are presently being mined at depths exceeding 1,000 feet and will in the near future be mined at even greater depths, where the problem of methane gas affecting the mining operations will be acute. It is calculated that approximately 90 pct of the methane is at depths greater than 1,000 feet, and over half of the gas is contained within only 12 pct of the study area which is under more than 1,500 feet of over- burden. Degasification in advance of mining will increase mine safety, reduce ventilation expenditures, increase productivity, provide an additional energy source, and make it possible to mine parts of deep coalbeds that probably could not otherwise be mined.

Jan 1, 1976

To monitor the quantity and quality of air in underground mines to assure safe working conditions. Approach Several mine air monitoring systems, consisting of sensing stations in the return airways and control stations on the surface, have been Installed and tested. How It Works Sensor stations are located at strategic places in the underground mine. At each station, the sensors measure air velocity, air temperature, methane concentration, and carbon monoxide concentration. In one system, differential air pressure between intake air and return air, is also measured. Output voltages of the sensors are converted to digital signals at the sensor stat ion; these signals are multiplexed so that data from all sensors can be trans-phone wire to a central station. There the data are displayed and alarms are triggered when the sensed values exceed (or in the case of air velocity, fall below) a preset value. In addition to receiving data automatically, the central station can poll individual sensors at any time.

Jan 1, 1978

To develop an in-mine water treatment system in which bacterial sulfate reduction and limestone dissolution continuously remove metals and acidity from contaminated drainage. Approach A section of mine tunnel was converted into a water treatment bioreactor by constructing cinder block dams and fang the area between them with a porous substrate mixture of limestone gravel and compost. Readily fermentable materials such as dairy whey, spent brewing yeast, or sugar were periodically added to the reactor. Mine drainage was impounded behind one of the dams and continuously percolates through the reactor substrate at a controlled rate. How It Works The reactor substrate soon becomes anaerobic after it is saturated with mine water. Under anaerobic conditions, sulfate-reducing bacteria consume the organic materials that are added to the reactor and generate hydrogen sulfide (HIS) and alkalinity. The H2S reacts with dissolved iron and heavy metals to form metal sulfide precipitates. The alkalinity raises the pH of the water and induces aluminum to hydrolyze and precipitate as aluminum hydroxide [Al(OH)3]. Additional alkalinity is generated by the continuous dissolution of the substrate limestone. Metal sulfide precipitates and Al(OH)3 are retained within the reactor, and the treated water is discharged. The underground location of the system allows year round operation.

Jan 1, 1994

By Launa G. Mallett, Kathleen M. Kowalski, Michael J. Brnich

The characteristics of leaders under the duress of an emergency are important in the development of emergency planning, training, and in the management of an actual emergency. Knowledge of human behavior is an important component in the formation of emergency strategies. The U.S. Bureau of Mines analyzed the leadership behavior in three underground mine fire escapes. The subjects described their escapes during open-ended interviews. Data were coded according to: (1) evidence of leadership behavior, (2) evidence of lack of leadership behavior, and (3) characteristics of the individual in each group who led the subjects out of the mines. This paper discusses the profile of six individual leadership characteristics which emerged from the data.

By Ann G. Kim

Methane in coal constitutes a serious hazard in coal mining. Draining the methane in advance of mining can mitigate this hazard, conserve energy, and offer economic benefits. This Bureau of Mines report evaluates the Pittsburgh coalbed in Greene County, Pa., to determine if advance drainage is feasible. The gas content of virgin reserves in Greene County is estimated at 100 to 200 ft3/ton, a total of over 370 billion ft3 of gas in an area approximately 310 mi2. Because of the similarity to natural gas, drained coalbed gas could be recovered and added to pipeline supplies of natural gas. The value of conserved gas would offset the cost of drainage and extend energy resources.

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 Elaine T. Cullen

Educating the public about the role of mining and minerals can be a challenge. While it sometimes seems that little is being done to counteract negative publicity, there are many exciting things happening across the country that are helping meet this challenge. This paper will discuss existing minerals education activities and will provide tips for developing successful programs for a variety of groups, from students to industry to minerals educators themselves. The paper will also include an overview of the 9th annual National Minerals Education Conference held in July 2000 in Spokane, WA.

By D. Harrington, B. W. Dyer

"One of the products of the activities of the United States Chemical Warfare Service is a simple device and method for nearly instantaneous determination of small quantities of carbon monoxide in air. Since the war, this device has been diverted to commercial uses, and is now being marketed in connection with rapid determination of the comparatively small but dangerous quantities of CO, which may be found in garages, in sewers, about blast furnaces, etc. Also, it probably has a definite field of use in both coal and metal mines in connection with fires and explosions, as well as in confined places after firing of explosives) the latter applica-tion being of especial importance in metal mining.The device as marketed is readily portable, being small and light enough to carry in a coat pocket of medium size. In operation, a sample of the air mixture is drawn into a small rubber bulb, then forced through a small glass tube filled with certain chemicals upon which CO has the effect of changing the original color from gray or white to shades of green, the deepness of the green determining the percentage of CO in the air. A color scale is attached for purpose of comparison and determination of CO percentage. Only a few minutes are consumed in obtaining the result, all work being done on the ground.The exact effect of minute quantities (up to 1/10 of 1 percent) of CO on the human system is somewhat uncertain, and much research has been and is being done to obtain definite data on this point. It is, however, definitely known that in air containing more than 1/10 of 1 percent CO men doing hard work are quickly and seriously affected. As the gas is tasteless, colorless and odorless, methods of determining the presence of both small and large quantities have been of much importance. Technical Paper 11 of the U. S. Bureau of Mines gives much data as to effect of CO on mice and canaries. It was found that mice show very little distress until the CO content is about 0.20 percent, but quickly succumb when that percentage is exceeded; canaries are somewhat more susceptible; they quickly show distress in as little as 0.15 percent 00, and soon collapse when that percentage is exceeded."

Jan 1, 1921

By B. Demoulin, J. Fontaine, R. Gabillard, P. Degauque

To realize a radiowave communication along mine galleries a few kilometers long without repeater, we show that it is possible to use a coaxial cable bearing an important surface transfer impedance like a transmission line with an inductive coupling to the transmitter and the receiver. We determine the electrical and geometrical constants of the cable and the optimal frequency.

Jan 1, 1973

By Robert F. Chaiken

A quasi-steady-burning channel model is used in this Bureau of Mines study to describe the conductive heat loss from an in situ coal combustor to the surrounding rock strata. The calculated heat losses are significantly greater than those previously estimated, but are still very acceptable from the viewpoint of energy recovery. Approximately 80% to 90% of the heat of combustion of the coal should appear as sensible heat of the gaseous exhaust, with exhaust temperatures in the range of 1,000° to 1,200° C. The effects of burning stoichiometry and channel size on the heat loss are also discussed in terms of the model. Such effects are shown to be compatible with an in situ combustion process even in thin seams. However, these results depend on gas leakage and adverse roof falls not being important factors in deter-mining the heat loss mechanism.

Jan 1, 1977

By John C. Edwards, Fred N. Kissell

Experimental work by the Bureau of Mines indicates that when a coalbed is degassed by boreholes, the flow of methane may actually increase with time. This phenomenon appears to be the result of a relative-permeability effect; that is, the coalbed permeability to the gas increases sharply with decreasing water saturation. This report reviews the background of experimental evidence indicating a relative-permeability effect, and presents the results of a computer simulation of two-phase flow in coal.

Jan 1, 1975