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By Peter F. Steidl

Seven degasification wells have been completed in the Pittsburgh coalbed at the new Emerald mine near Waynesburg, Pa. Funding was provided by the Bureau of Mines to perform stimulation treatments on five of the wells, to show that this is a feasible and economical means of degasifying part of a coalbed. The seven wells ranged in depth from 590 to 910 feet. Stimulation treatments used 25,260 to 42,660 gallons of foam and 7,400 to 12,800 pounds of 20/40-mesh prop sand. Pumping rates were 10.8 to 11.6 bbl/min and treating pressures were from 1,050 to 1,600 psig. On the day following stimulation, gas production ranged from a few hundred cubic feet per day to more than 100,000 cu ft/day.

Jan 1, 1978

Provide a lighter, smaller apparatus for more gently supporting electrical cable as it is raised or lowered in a well as compared with the conventional method of using a winch and pulley. Approach The conventional method of running cable into a well is to use a winch to pull the cable over a pulley located at the end of a boom placed over the well. This has the disadvantages of being bulky and of placing a concentrated strain on the cable at the point where it moves over the pulley. These disadvantages are overcome by using a "Chinese finger" cable grip assembly to hold and release a multiple conductor cable.

Jan 1, 1986

By W. P. Yant

Public interest in atmospheric pollution by automobile exhaust gas and in the ventilation of vehicular tunnels makes it desirable to ascertain whether the use of modern automobile fuels is tending to change the amount and composition of the products of combustion. The Bureau of Mines, in cooperation with the Ethyl Gasoline corporation4, has completed a series of testis to determine whether any significant difference exists in the carbon monoxide content of the exhaust gas produced by an internal-combustion engine when its fuel is changed from straight gasoline to the same gasoline containing Ethyl fluid whose active ingredient is tetraethyl lead. In the tests data was sought relative to the composition and mount of the gas produced by ordinary comparatively low-compression motors as well as by higher-compression motors in which distinct detonation occurred with straight gasoline, but which operated without detonation when using the same gasoline containing tetraethyl lead.

Jan 1, 1929

Develop a metal substitute which is more plentiful and less expensive than the metals currently being used in high performance, permanent magnets, while maintaining the quality of the magnet. The New Alloy The rare-earth metal used in most high performance magnets is samarium, an expensive metal of limited availability. Cobalt is also used in high performance magnets, but supplies of this metal also are limited because it is not domestically mined and must be imported. The Bureau of Mines embarked on research to find a less costly domestic: metal source for use in industrial magnets. The alloy found most promising consists of mischmetal, a relatively abundant, naturally occurring mixture of rare-earths, which can be used as a replacement for samarium. Additives of copper, magnesium and iron used in combination with mischmetal aid in replacing some of the cobalt needed for the magnets.

Jan 1, 1983

Coal-bearing beds underlie 23,000 square miles, about one third of Missouri's total area. Twelve out of more than twenty named coal seams have been or are being commercially mined. The remainder are too thin for commercial production. The coal is high volatile bituminous, with reserves estimated to be six billion tons, 1.24percent of U.S. coal reserves. Coal-bearing strata are generally thin seams which can be up to five feet thick. Typically, mined seams are about 28 inches thick. Coal deposits were first mined in Missouri in the 1840s, with the coal used primarily for domestic heating and blacksmithing. Production increased with the introduction of steamboats on the Mississippi. Coal production in 19 17 was six million tons. Production has steadily declined from a high of nearly seven million tons in 1984 to 2.3 million tons in 1991. Declining production is the result of several factors, including competition from other energy sources and the high sulfur content of Missouri coal. Today, coal-fired electric generating plants are the biggest consumers of Missouri coal. The Missouri regulatory program was conditionally approved November 21,1980, and fully approved January 17,1983. Its Abandoned Mine Land program was approved January 29, 1982.

Jan 1, 1992

To reduce front-end loader (FEL) collision accidents by detecting obstacles in the rear blind area. The Problem Federal regulations require an audible backup alarm to activate when an FEL is backing. Since the device is constantly being activated, the warning soon becomes a normal part of the mine environment and is less effective as a warning device. Also, when several machines are working together, it is difficult to detect by ear alone just which machine is backing. Approach The Bureau defined the location for hazard detection to include an area extending 15 to 20 ft behind the rear bumper of an FEL. Then, existing surveillance and detection technology was assembled, ruggedness, and applied to the FEL's rear blind area to form a new discriminating backup alarm system employing either infrared light, ultrasonics or radar

Jan 1, 1986

Develop methods to detect and repair poorly functioning dust collectors on roof bolters. Approach In conjunction with a research project to reduce silica dust in coal mines, a variety of roof bolting machines operating under different conditions were examined to find out how much these machines were contributing to the silica dust problem. Results The investigation concluded that if the bolting machines' dust collector is properly maintained, very little dust can be measured in the air, even with minimal airflow over the bolter. Poor maintenance, however, frequently results in high dust levels. Three major problem areas were found. These were: (1) filter leaks, which allowed dust to escape, (2) accumulations of dust in the collection system, and (3) low airflow at the bit due to hose, fitting, and relief valve leaks.

Jan 1, 1984

By Dhaval Patel, Kim Witte, Charles Vaught, Michael T. Stephenson, Steve Booth-Butterfield, Cynthia Zuckerman, Brian L. Quick

This longitudinal field study was designed to encourage Appalachian coal miners in West Virginia and Pennsylvania to engage in hearing-protection behaviors. Method: Participants were mailed postcards that featured either a positive, negative, or neutral message on the outside of the postcard and a message encouraging hearing protection behaviors on the inside. The first posttest measurement of the effectiveness of the persuasive messages was conducted about a week after the postcards were mailed. The delayed posttest measurement was conducted six weeks later. Results: Responses from 307 coal miners revealed that the positive or neutral messages generated significantly more self-reported hearing protection behaviors than the negative message. Identical results were obtained in a delayed posttest assessment of miners' self-reported hearing protection behaviors. The positive message was also more effective than either the neutral or negative message in preventing defensive mechanisms from emerging over time. Impact on Industry: Positive and neutral messages were convincingly more than negative messages in facilitating self-reported hearing protection behaviors among coal miners. Similarly, the positive messages kept defensive processes at bay. Keywords: Hearing protection; Hearing loss; Coal miners; Campaign; Messages

By David A. Monaghan, Kenneth R. Maser, Adi R. Gurdar, D. Randolph Berry

APPENDIX C SCALING RELATIONSHIPS 1. Scaling Law for Fly Ash Crater Formation The scaling law derived for predicting crater diameters at different scales is developed below by considering the equation of motion of individual fly ash particles. It is assumed that the air drag on each particle is characterized by Stokes flow, and at the borehole - passage intersection the air velocity and the fly ash particle velocity are the same. The equations of motion for a fly ash particle are the following, (see Figure C-1).

Jan 1, 1973

By D. E. Wolfson

The Bureau of Mines investigated the use of preheated coal in carbonization operations. Liquor yields and coking times were reduced, coke quality was improved, and smokeless pipeline charging to coke ovens should eliminate a serious source of pollution.

Jan 1, 1972

By Albert E. Schreck

THIS CHAPTER concerns such minor nonmetals as greensand, meerschaum, mineral wool, staurolite, and wollastonite. GREENSAND Output of greensand (glauconite) was slightly higher than in 1958. Open pits of The Kaylorite Corp. (Calvert County, Md.), National Soil Conservation, Inc. (Burlington County, N.J.), and Inversand Co." (Gloucester County, N.J.) accounted for the entire production. Soil conditioning used about 72 percent of the greensand sold. The remainder was used as a water-softening agent. Prices for greensand, f.o.b. mine, ranged from $13 to $70 per short ton.

Jan 1, 1960

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 M. K. Larson, J. K. Whyatt, F. M. Jenkins

The U.S. Bureau of Mines conducted an overcore stress measurement on the 5300 level of the Lucky Friday Mine, Mullan, ID, to investigate the stress regime around an experimental stope in a rock-burst-prone mine. The result indicated a stress field with unexpected magnitude and orientation [F . 135 MPa (19,600 psi) oriented S 80E1W]. An unusual amount of rock-burst activity was encountered during subsequent excavation. A careful review of the overcore data suggested the overcore strain measurements were valid. Moreover, concentrated rock-burst activity suggested that the measured stress field did exist, but was localized and therefore did not represent the far-field in situ stress field.

Jan 1, 1995

By Nicholas G. Theofilos

Ecuador's real gross domestic product (GDP) increased 6% in 1976 despite persistent shortages of electrical power and essential fuels, which caused factory slow-downs and shutdowns. Petroleum export earnings, which made up more than 50% of total export value in 19716, totaled $565 million, a 9% increase over those of 1975. A new 60,000-barrel-per-day oil refinery at Esmeraldas was scheduled to go on- stream in mid- 1 97 7, operating entirely on Ecuadorean crude. Corpración Estatal Petró1era Ecualtoriana (CEPE) started construction of a 600-kilometer network of product pipelines which was scheduled to be completed in 1977 to coincide with the completion of the refinery.

Jan 1, 1980

By H. Kenneth Sacks

The Bureau of Mines has developed hardware for electromagnetic (EM) detection and location of miners trapped in underground coal mines. This report describes a technique for using the developed equipment for locating uncased boreholes underground. Results of several field and laboratory experiments are described.

Jan 1, 1978

By M. M. Tilman

A series of alloys was laboratory prepared by adding up to 4 weight-percent cobalt to the basic composition of type AM 350 (AISI 633) stainless steel. Aging curves were established for each alloy at 750° F, 850° F, and 950° F for lengths of time up to 100 hours. A series of annealed steels containing as much as 1 weight-percent cobalt was cold-rolled 50 percent and aged for 3 hours at 850° F. No improvement in hardness due to cobalt was observed in the steels transformed by heat treatment. Slight improvements in hardness were observed in the steels transformed by cold working.

Jan 1, 1968

By M. Terry Hoch, George J. Karabin, James M. Kramer

This paper introduces the fracture mechanics approach—a unique way to predict the stability of a coal mine panel. The technique uses analytic equations to calculate the stress, strain, and yield characteristics of coal support systems. It uses fracture mechanics to model almost every type of mine support structure. Another feature is a method that incorporates field-tested knowledge into the analytical analysis. For example, this technique can model the yield characteristics of a coal seam by combining empirical pillar strength equations into the analytic analysis. It may be possible to simulate multiple-seam mining by incorporating subsidence methods into the analysis. The method is simple and quick, which makes it attractive for stress analysis software. It should be more accessible to those in the mining industry who do not have expertise in rock mechanics or numerical modeling. Although the purpose of this research is for modeling coal mines, it should be adaptable to any mine in a tabular deposit.

Jan 1, 1999

By James R. Wait

It is the purpose of this paper to review theoretical model concepts in through- the -earth transmission of electromagnetic waves. While the subject is very broad in its defined scope, we will be conscious of the specific applications to mine rescue and emergency telecommunications in coal mine environments. The plan of the paper is to outline previous theoretical efforts without attempting to attach names or organizations to the specific developments. However, we include a guide to the literature as an appendix. Without pretending to be entirely impartial we include a critique of the limitations of the available analytical models. As I see it the central problem is to calculate the steady state mutual impedance of a four-terminal network that is the black box characterizing the through-the-earth path. Problems of secondary importance include the determination of the input impedances of the two pairs of terminals and the associated transient responses. [ ]

Jan 1, 1973

By Thomas R. Bur

The amplitude of the first peak of an ultrasonic pulse which has traversed the diameter of a sphere is obtained for many directions in the sphere. This amplitude is relative to an input which is held constant for all measurements on a given sphere. Since the boundary conditions, distance of travel, and the controllable experimental factors are constant for all measurements, variations in this amplitude reflect variations in the attenuation or absorption with direction. The data are plotted and contoured as an equal area projection. The attenuation symmetry is the symmetry expressed by the contour pattern. Analysis of the data from several rock types indicates that the amplitude expresses a higher percentage of anisotropy than the velocity. In most cases the attenuation symmetry appears to be of the same system as the elastic symmetry expressed by the velocity. Results are shown for three rock spheres.

Jan 1, 1969

By A. W. Henderson

Methods for converting WOCl4 to WCle were investigated in small-scale, laboratory apparatus to devise a method for preparing pure WCls suitable for conversion to tungsten metal. Chlorine, COCI2, and CCI4, alone and in combination with various forms of carbon, were tested as chlorinating agents at various temperatures. More than 95 percent conversion of WOCl4 to WCls was achieved with all reagents at 8000 C in the presence of activated carbon. Only CCl4 maintained its effectiveness in the absence of carbon at 800° C. The effectiveness of carbon was found to be related directly to its surface area.

Jan 1, 1968