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By C. P. Lazzara, R. A. Franks, G. F. Friel, J. C. Edwards, J. J. Opferman

It was determined that a selection of different types of fire sensors could be used to discriminate mine fires from nuisance emissions produced by diesel equipment. A neural network (NN) was developed for application to coal, wood, and conveyor belt fires in the presence of diesel emissions and evaluated with the successful prediction of twenty-two out of twenty-three mine fires based upon a fire probability determination. The optimum sensor selection for the NN was comprised of a carbon monoxide (CO) sensor, two different types of metal oxide semiconductor (MOS) sensors, and an optical path smoke sensor.

By Joseph B. Huvos

Said to be one of the world's most under-developed countries, Benin had a gross national product (GNP) estimated at $1 billion in 1980.2 Contribution of the mineral industry such as cement and limestone to the GNP was negligible, but exploration of mineral potential continued Minerals.-The United Nations Development Program (UNDP) conducted an investigation of three deposits from 1977 to 1980: Phosphates (Mekrou), gold (Perma), and chromite (Buem). A phosphate rock deposit containing about 4.5 million tons recover- able by opencast techniques was discovered. It was not known if the gold and chromite deposits were recoverable economically. Iron ore deposits of some 230 million tons near Loumbo-Loumbo are at present not exploitable because of lack of infrastructure in the northern part of the country. Geologic mapping with British and French assistance was also pursued in 1980.

Jan 1, 1982

Enable mine personnel to determine the effectiveness of and to optimize the mine fire stench warning system without resorting to costly trial and error fire drills. Approach The mine fire stench warning system is used by underground metal/nonmetal mines to warn mine workers of a fire or other emergency. Stench is released directly into the mine ventilation and/or compressed air lines, and its repulsive odor warns miners to evacuate the mine or to follow other established emergency procedures. Unfortunately, since most deep metal mines have complex ventilation systems, some areas of the mine may receive nauseatingly high concentrations of stench while other areas, in more remote locations, may receive no warning or greatly delayed warring at best. The Bureau of Mines, through research, endeavored to solve this problem with a computer modeling system designed to calculate the distribution of odorant by the stench warning system.

Jan 1, 1986

Table XXXIII itemizes the cost associated with the installation of an irrigation system and the application of latex and water in the three experimental areas at Lanse. There were no external labor charges (non- Research Center) except for the installation of the water meter. Cost of pipe and fitting are high because long lines were required at each of the three different locations; these costs were minimized by using plastic instead of metal pipe. Fifteen of the seventeen drums of latex received were used, five drums for each area. [ ] In tank-car lots latex would cost about $0.25/lb so that raw material cost for a 4000 lb/acre application would be in the range of $1,000 per acre. Equipment costs for setting up and irrigation are sensitive to size of area to be irrigated, design of system, and availability and cost of water. A realistic range is estimated to be between $200-500/acre.

Jan 1, 1972

By Launa Mallett, Charles Vaught, Jr. Brnich

This paper introduces a technique for incorporating employee participation into the prevention component of a contingency plan. Companies sometimes focus so much energy on response that they forget to put resources into the basics of emergency prevention. The training program discussed here was designed to make employees part of the prevention system. Examples of training materials from the program are provided, a sample method for introducing risk assessment to employees is shown, and a strategy to address limited training time using short videos is explained. Methods for tailoring the training to any worksite and for specific risks are also included. The program is being designed and tested by the Pittsburgh Research Laboratory/NIOSH and employees of an underground coal mine. Examples are taken from the implementation of the program at the mine during the summer and fall of 1998. Results of the program evaluation and lessons learned during the implementation are discussed.

By Joseph Cervik, J. H. Perkins

The Bureau of Mines has conducted desorption work on fine coal particles at near atmospheric pressure. An apparatus has been developed that uses a capacitance manometer to measure desorption of methane from coal particles up to 2 inches in diameter and pressures up to 1,000 psi. This will make it possible to duplicate the desorption process as it occurs in its natural under- ground environment.

Aug 1, 1970

By John C. Edwards

To have the capability to predict the development of localized spontaneous heating within a porous coalbed that is subjected to forced air ventilation or in an otherwise quiescent environment in which buoyancy develops, the Bureau of Mines developed three time-dependent mathematical models, which were used to calculate the temperature increase associated with chemisorption of oxygen by the coal. In each model, spontaneous heating is driven by an Arrhenius first-order reaction between the oxygen and coal. Two models are two-dimensional, and one is one-dimensional. In the first two-dimensional model, a constant-velocity forced convection airflow is specified; and in the other, buoyant flow is allowed to develop in the absence of forced convection. The third model evaluates the airflow from Darcy's law and a specification of the pressure at the surface of a one-dimensional porous coalbed. Numerical computations demonstrated how each model could be used to predict the onset of spontaneous heating when the porous coalbed was subjected to constraints of an imposed internal heat source or a high- temperature airflow. The effects of particle size and coalbed compaction upon spontaneous heating were examined with the third model.

Jan 1, 1990

Improve the effectiveness of person-wearable self-contained self rescuer (PWSCSR) training by enhancing the memory retention of trainees in proper donning procedures. Background In the fall of 1989, a total of 185 miners and inspectors were trained by Bureau of Mines personnel to don the SR-100 PWSCSR using the Bureau's 3+3 method. With the exception of a few individuals, miners were trained underground in an area set up within their working sections. The instructional protocol was as follows: (1) after placing an SR-100 simulator (equipped with a cleaned and disinfected mouthpiece assembly) on the mine floor in front of the worker, a researcher guided him or her step-by-step through the complete donning procedure, (2) the miner was required to perform each step slowly, methodically, and correctly while being talked through the sequence, (3) following this pre-practice instruction, the apparatus was repacked and the subject donned the device without coaching, while being evaluated, (4) if an error was made, the worker received corrective feedback, the unit was repacked, and the entire donning trial was redone. This procedure was repeated until the miner achieved a perfect 3+3 sequence.

Jan 1, 1990

By G. F. Kuncir

The funding tables included in this report were defined in support of an evaluation of the Advancing Oil Sale Mining Technology Program undertaken by The Aerospace Corporation. Because of the sensitive nature of the fiscal planning information, the tables have been separated from the main analysis report and given a limited distribution.

Jan 1, 1977

By M. E. Tyrrell

The purpose of the work leading to this report was two-fold: (1) To determine the properties of cemented tungsten carbide modified by the addition of one, two, and five percent of titanium diboride, and (2) to compare the properties of these mixtures when sintered, hot-pressed, and flash-welded (resistance-sintered). Minor additions of titanium diboride to mixtures of 94 percent WC and 6 percent Co decrease mechanical strength but increase oxidation resistance in proportion to the amount of the addition. One percent of titanium diboride increased the hardness by 2 Rockwell A units. Hot-pressing produced compacts with the highest density and the best mechanical strength, but losses of cobalt were high and grain growth was pronounced.

Jan 1, 1962

By Fred Leighton

The Bureau of Mines monitored a rock-burst-prone pillar in a metallic ore vein, up to and through failure, to measure its reactions to increasing loads, as it was mined. Three parameters were monitored: the stress changes at chosen points within the pillar, the displacement characteristics of the drift above the pillar, and the micro-seismic activity in and around the pillar. In descending order of effectiveness, the microseismic technique, vibrating wire stress measurements, and displacement measurements reflected the pillar reactions, and all showed good correlation to one another. A major rock burst in the pillar, which destroyed about 100 feet of drift above the pillar, occurred at the end of this study. This burst was preceded by a large anomaly in the microseismic activity in the failure area.

Jan 1, 1982

By B. E. Davis

As part of its program to increase the domestic availability of critical minerals, the Bureau of Mines conducted characterization and beneficiation studies on a St. Johns County, Fla., phosphate ore that was mined by borehole mining. Results revealed that the ore from this test mine was mostly sand-size carbonate-fluorapatite and quartz and contained 24.6 percent P205. Concentration by various flotation techniques produced phosphate concentrates that ranged, in percent, from 30.0 to 31.4 P205, 0.73 to 0.80 MgO, and 2.8 to 7.2 acid insoluble. Recovery of the phosphate from the ore ranged from 89.4 to 96.3 percent.

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 W. S. Sanner

Grinding experiments were conducted to determine the finest anthracite particles that could be produced in a ball mill. Continuous and batch tests were run in a dry-grinding ball mill. Batch grinding produced the finest coal particles. They averaged 2.2 microns in diameter and were 99.0 percent smaller than 37 microns. Continuous grinding yielded a product 6.1 microns in diameter, with 96 percent smaller than 37 microns.

Jan 1, 1968

By J. S. Peterson, G. P. Cole

The National Institute for Occupational Safety and Health (NIOSH), Pittsburgh Research Center (PRC), has conducted research to improve electrical fault detection on coal mine direct current (dc) trolley systems. Present circuit breaker protection systems are current-magnitude-based and cannot discern between normal traffic and high resistance electrical faults. Tests were conducted at cooperating mines to assist in developing a neural-network-based detection algorithm for distinguishing between electrical faults and normal operation. The Fast Fourier Transform of the trolley rectifier current signature served as baseline data for the neural network. During field tests, the algorithm performed with greater than 90% accuracy.

By Pablo Velasco

Ecuador had limited mineral output, al-though the Government attempted to stimulate metallic mineral exploration and also evaluated a gypsum and a phosphate deposit. A pilot plant to exploit gold deposits was established, and there was extensive gold exploration activity in southern Ecuador. Domestic output of iron and steel declined sharply. Among all minerals, petroleum output was the dominant factor with both exports and production increasing significantly over that of 1988. Crude oil exports contributed 63% of total export earnings and about 70% of the central Government's revenue.

Jan 1, 1986

By R. V. Lundquist

Past reports by the Bureau of Mines have described the extraction of alumina from numerous aluminum silicate materials by the lime-soda sinter process. The results from pilot-plant investigations of six materials, with alumina-to-silica mole ratios from 0.3 to 8.7, indicated a relationship between the alumina-silica ratios and the processing characteristics of the sinter. A series of laboratory tests was conducted to define this relationship. Sinter and leach tests determined that an alumina-to-silica mole ratio of 0.90 or greater resulted in the best alumina and soda recoveries while leaving the leach slurries practically free from any tendency toward gelation. The widely different chemical and mineralogic properties of the various aluminous materials used in compounding the mixes had no perceptible effect on the leaching characteristics of the sinter. The blending of low-cost, high-alumina materials with aluminum silicate materials to give an alumina-to-silica mole ratio of 0.90 or greater would improve alumina and soda extraction and minimize operating problems in the lime-soda sinter process.

Jan 1, 1970

To quickly and more reliably measure the alignment and deflection of mine guides used to run skips and cages into a mine shaft. The Problem Conventional mine guide alignment measuring systems require the use of a plumb bob and tape measure. This method is not only laborious, but it is time consuming as well. Approach Aware of the drawbacks of the current measuring method, the Bureau of Mines designed a self-contained instrument system that can accurately perform vertical guide alignment and deflection measurements by remote control. How It Works The Bureau-developed instrumentation system, called the Guide Alignment Measuring System (GAMS), is based on conventional mechanical electronics using inclinometers and displacement transducers. The instrumentation system is attached to an operating skip or cage where it functions as a completely self-contained measurement system, operating in conjunction with nor-mal travel of the skip or cage. An on-board tape recorder or a mini-computer with memory can be used to record all telemetry.

Jan 1, 1987

To provide safer and more efficient mine operations by improving the operational performance of underground trolley line communication systems. Approach The dc trolley line provides a convenient means of In-mine communication since it can carry signals to each phone on the system whether the phones are in mine vehicles or in a fixed location such as that of a dispatcher. In many cases, however, the system does not perform satisfactorily. Short communication range, noise, and dead spots commonly interfere with effective communication. These problems are inherent with the trolley line, which was designed to transmit power and not communication Signals. As a power line, the trolley line is connected to rectifiers and feeds many loads such as motors, water pumps, track block lights, etc. Each of these devices represents a low impedance radio frequency (RF) shunt that seriously reduces carrier communication Signals. Performance is therefore often poor and can be improved only if the effects of the various shunts can be reduced. The Bureau of Mines has developed numerous methods applicable to either existing or planned phone systems which can improve communication range and reduce the shunting effects of the various loads.

Jan 1, 1983

By Owen W. Terry

During the summer of 1943 the Bureau of Mines conducted an investigation and program of churn drilling on the McIlhon and adjoining Pearson land in the Mineral Point district of Iowa County, Wis. Sixteen holes, aggregating 1,570 feet .of bore, were completed. The work was undertaken as part of a general investigation of the zinc-and lead-producing area of southwestern Wisconsin at a time when great effort was being made to increase the production of Metals important to the war program. The Bureau's drilling program supplemented a previous drilling pro-gram conducted by the Vinegar Hill Zinc Co., and demonstrated the presence of a strongly mineralized zone at relatively shallow depths.

Jan 1, 1948