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By J. W. Paul

This paper deals with the third phase of on extensive research on coal-mine ventilation factors. A comprehensive report of the entire work is in course of preparation, but abstracts of the various chapters are being prepared in order to make the results public as rapidly as possible. Parts I and II of this paper were issued Serial 2621 and Serial 2647 of the Bureau of Mines in July and October, 1924. They dealt with the resistance of unobstructed entry and the resistance caused by mine cars in untimbered entry. Description of the Tests After the resistance of unobstructed entry and of mine cars in untimbered entry had been determined by tests in the Experimental Mine, three different types of timbering were installed in the test section and the increased resistance caused by the timbering was determined.

Jan 1, 1925

By James P. Rider

This U.S. Bureau of Mines report describes a viewing transformation algorithm that generates a perspective view of a three-dimensional scene. This tool may be used by researchers to improve mine safety by assessing the visual capabilities of a mobile equipment operator. Three-dimensional transformations used to build the viewing transformation and techniques used to project the image onto a two-dimensional display screen are defined. The algorithm is written in the C-programming language and designed to stress portability, allowing it to work without significant modifications on numerous computers. A listing of the computer routines along with sample output is included in the report.

Jan 1, 1992

By Ronald D. Hill, Elmore C. Grim

Some of the terms defined here are not used in the text. However, the terms will be useful to those interested in this and other publications in the field of coal surface mining.

Jan 1, 1974

By Fun-Den Wang

Finite-element structural analyses were performed to determine the stress distribution and displacements around a single rectangular coal mine opening in a multilayered rock system. The effects of changes in mechanical properties of roof and coal layers, roof layer and mine opening geometry, horizontal-to-vertical load ratio, and structural geologic features on the stress distribution about the opening were studied. Variability in the stiffness and relative thickness of the immediate roof layers can produce a considerable difference in the stress distribution about the opening as compared with that of a homogeneous material. Changes in opening width and horizontal-to-vertical load ratio have different effects on the stress distribution about the opening depending on the composition of the roof layers. In general, where a stiff layer exists in the roof at the surface of the opening, the stresses are higher in the roof and ribs around the opening. Horizontal changes in facies in the roof layers produced by structural geologic features can also greatly alter the stress distribution about the opening compared with the simple layered cases.

Jan 1, 1974

This chapter describes the adverse health effects associated with exposure to respirable coal mine dust. Epidemiological studies of underground and surface coal miners in the United States and other countries are discussed. Also discussed are animal studies that add to our understanding of particle deposition and retention in the lungs and associated disease responses. This chapter emphasizes studies that (1) were performed since the passage of the Federal Coal Mine Health and Safety Act of 1969 [P.L. 91- 173], (2) used standardized methods of exposure monitoring and disease classification, and (3) investigated exposure-response relationships between respirable coal mine dust exposure and disease. Several published review articles contain further discussion of health effects studies of coal miners [Attfield and Wagner 1992b; Petsonk and Attfield 1994; Cotes and Steel 1987; Merchant et al. 1986; Morgan and Lapp 1976; Morgan 1975].

Jan 1, 1997

By C. W. Dwiggins

The Bureau of Mines characterized the chemical and physical properties of metallo-organic materials in petroleum to determine their effect on petroleum production and refining. The structures and physical properties of porphyrins and materials that normally contain metalloporphyrins such as crude oils and asphaltenes were investigated using elemental analysis, NMR analysis, absorption spectrometry, and small-angle X-ray scattering. Petroleum fractions greatly enriched in metalloporphyrins were obtained using asphaltene precipitation, liquid extraction, and large-scale liquid-solid chromatography. Selected fractions containing porphyrins were further purified by chromatographic methods, crystallization, and demetalation followed by chromatography. Nonporphyrin metals could not be appreciably concentrated from the bulk of the asphaltene.

Jan 1, 1969

By Lester G. Morrell

UPTREND in value of mineral production in the Commonwealth of Australia continued in 1963, again pacing the country's general economic growth rate. Increases occurred in output of most raw and processed mineral products, including bauxite, copper, iron ore, pig iron, steel, lead, zinc, cement, gypsum, pyrite, coal, and refined petroleum products. Although the economy of Australia has been traditionally based on wool and agricultural products, in recent years the country has become highly industrialized. Nearly one-third of the 3.6 million total civilian labor force is engaged in manufacturing. Employment in mines and quarries occupies 1.4 percent of the national labor force.

Jan 1, 1964

By D. B. Taliaferro, David M. Logan

which an operator may obtain detailed information regarding all projects in the State. It is the purpose of this report to present data such as volume of oil produced monthly, volume of water injected monthly, spacing of wells, number of injection wells and oil wells, and other such pertinent information regarding every project in the State whether active or abandoned and whether a success or a failure. It is believed that with these data it is possible to analyze water-flooding operations in this area more completely than has been possible in the past. As the title indicates, the report is essentially a history, and ordinarily no opinion is given as to the cause for the success or failure of individual projects. Increasing the production of oil is exceedingly important at this time, and one method by which it may be done most readily is by providing additional energy for the movement of oil in many of the older fields. In many oil fields the predominant force that drives oil through the porus reservoir rocks to wells is the gas dissolved in or otherwise associated with the oil under pressure. As the pressure in the reservoir declines in consequence of the removal of fluid, gas comes out of solution in the form of minute bubbles; as the pressure is reduced further, the expansion of these bubbles forces part of the oil toward the areas of lowest pressure and into the producing wells. The physical properties of the oil and the gas governing their flow through reservoir rocks to wells differ, and much of the gas slips past the oil leaving large quantities of oil in the reservoir when the pressure has been exhausted. Often the natural productive life of fields is prolonged by reducing the pressure in oil wells below atmospheric with vacuum pumps; but the ad- ditional energy made available in this manner is limited to less than 1 atmos- phere of pressure, and even after the extended application of "vacuum" to a petroleum reservoir large quantities of oil are left unrecovered in the porous rocks and sands.

Nov 1, 1943

Efficiently clear ice and frozen materials from ore-handling equipment. Approach Compressed air-propane torches that develop a high energy flame jet were used instead of ordinary propane torches. How it Works A high velocity high temperature stream of gases impinges on the ice and frozen materials to both melt and blast them away. This hot gas jet is at 3,000°F temperature and moving at 3,000 feet per second. In the photograph below, the jet is being used to clear frozen taconite from a grizzly. The functions of the compressed air-propane torch are as follows. The air heater assembly, which is mounted on a wand, con-

Jan 1, 1980

By A. Mayton, A. Brien, W. Porter, O&apos

In 2004, management at Unimin's Gleason, TN operation began implementing ergonomic interventions specifically targeted to reduce risk of musculoskeletal injuries (MSIs). Together with corporate and site management, Unimin identified work site hazards and began to modify work practices/equipment. Some interventions were relatively simple and were implemented immediately. Others, like improvements to a mobile shredder, were more complex but were eventually resolved through a participatory approach with employees, management, manufacturers and NIOSH. This paper discusses ergonomic interventions that were successfully implemented using a bottom-up approach to reducing the risk of injury.

Provide an operator cab to assure protection, comfortable use of controls, and good visibility. Approach A cab which raises and lowers by pivoting about d horizontal axis was Installed on two S&S cleanup tractors and tested in two underground working mines. How It Works Hydraulic cylinders actuated by a lever inside the cab cause the cab to pivot about a horizontal axis. This action raises or lowers the cab height. The total cab excursion is 14 inches. A release valve in the hydraulic system allows the cab to lower automatically if struck by a roof load or overhead obstruction. The pivoting action of the cab is engineered so that the operator maintains comfortable use of all controls at all cab heights. The movement is such that the angular relationship of the operator's ankles With the tram and brake foot controls IS consistently within 90 to 100 degrees. Figure 1 outlines the approximate position of the operator at three cab elevations.

Jan 1, 1977

Assist in controlling or extinguishing fires that occur in abandoned mine lands (AML) by providing a compilation of information on past fire control projects, the estimated extent of the current problem, and factors affecting the occurrence, propagation, and extinguishment of AML tires. Conventional fire control methods and their probable effectiveness are evaluated. Background Fires that occur in abandoned coal mines, waste banks, and coal outcrops constitute a serious health, safety, and environmental hazard from toxic fumes, deterioration of air quality, and subsidence. Although fires on AML occur in every coal-producing State, the severity of the problem varies, with most underground fires occurring in Kentucky, Pennsylvania, and Wyoming. Surface fires are prevalent in Kentucky, Pennsylvania, and West Virginia. Methods to extinguish or control AML fires, including excavation, fire barriers, and scaling, are generally expensive and have a relatively low probability of success (see figures 1 and 2). Bureau of Mines Study The Bureau compiled information from a variety of sources and found that the problem of AML fires is a serious one. Such fires can involve a high degree of hazard and can be difficult and costly to control. AML fires usually involve smoldering combustion in outcrops, waste banks, or abandoned mines. Given the nature of these fires, it is unlikely that the extent of the problem or the cost of solutions will decrease in the near future.

Jan 1, 1992

Reliably detect fires by sensing sub-micrometer-sized particles released into the air by smoldering or burning materials. Approach An extremely sensitive, ionization-type fire detector has been built that continuously draws air samples through its ionizing field and collects the ionized smoke particles downstream, thereby generating a proportional electrical output signal. (An offshoot instrument measures the size distribution and number of sub-micrometer particles in air.) How It Works Mine air to be monitored is drawn through the instrument assembly by a small pump. A pre-filter and cyclone remove dust particles and other particles larger than 0.6 micrometer diameter. The air and remaining aerosol-sized particles flow through a gastight tube which contains the detector. See diagram. Smoke and other sub-micrometer-size particles moving Into the detector, pass through an Ionizing field, and are struck by alpha particles released from radioactive source located on the axis of the tube, The alpha particles move radially outward until they strike smoke particles or molecules of air or water. When struck, a smoke particle or molecule loses an electron and becomes positively ionized.

Jan 1, 1979

By Robert P. Vinson, Fred N. Kissell

This report describes three coal mine ventilation studies by the Bureau of Mines in which sulfur hexafluoride (SFG) was used as a tracer gas. One of these studies was conducted to determine air movement and leakage in a sealed area. Another was run to determine the ventilation efficiency of a bleeder system. Finally, a study was made of air leakage across permanent stoppings of parallel intake airways. These studies proved sulfur hexafluoride to be a useful addition to the equipment commonly used in coal mine ventilation analysis.

Jan 1, 1976

By J. R. Allsup

The Bureau of Mines studied the characteristics of simulated coal gas as an automotive fuel in two multicylinder vehicles in a standard and high-compression-ratio engine configuration. While using simulated coal gas fuel, increasing the engine compression ratio improved the fuel economy and vehicle performance but increased hydrocarbon emissions by 40 pct. photochemical reactivity of exhaust hydrocarbons was found to be extremely low using the coal gas fuel. An oxidizing catalyst used with the simulated coal gas fuel eliminated all but trace amounts of carbon monoxide and reactive hydrocarbons in the exhaust. Spark gap geometry and firing voltage were varied and, within the range tested, had little effect on vehicle performance and emissions using simulated coal gas fuel.

Jan 1, 1975

By Joseph E. Matta

The Bureau of Mines conducted tests using a tracer-gas technique to measure the effectiveness of the jet fan, which is often employed in mines to ventilate dead headings. Results of these tests show that jet fans can (1) ventilate dead headings beyond the maximum penetration distance indicated by smoke-tube detection of air movement, and (2) redistribute available fresh air through larger working areas. However, if the fresh air base is insufficient, the fan will merely recirculate the contaminated air and disperse it over a larger volume.

Jan 1, 1978

By A. W. Deurbrouck

This Bureau of Mines report describes the washability characteristics of 14 coalbed samples collected in Wyoming. Such data is needed to evaluate the quality of the coals of the West where most of our low-sulfur-content coal reserves are found. Of the 14 samples included in this report 13 had a total sulfur content of 1.1 percent or less. All of the samples contained low per¬centages of ash or could be readily washed to a desirable ash level with minimal loss of yield. The coals ranged in rank from high-volatile B bituminous to subbituminous C, although 10 of the samples were high-volatile C bituminous. The coalbeds varied in thickness from 4.5 to an unknown thickness greater than 67.5 feet.

Jan 1, 1971

By E. D. Wilson

This is the second of a series of progress reports describing work undertaken at the San Manuel copper mine to study the geologic factors influencing block caving of the deposit. The first report described the work done from April 1954 to March 1956.3/ This report describes the progress from March 1956 through March 1958 and presents additional maps, factural data, inferences, and conclusions resulting from a continuation of the underground geological work. As outlined in these reports, the study thus far has shown that the principal geologic factors affecting block caving are structure, rock types, alteration, mineralization, oxidation, and presence of water. Structure is fundamentally the most important. Systematic fracturing governed the extent and grade of primary ore mineralization and tangibly affects the subsidence or ground movement, which extends from the mine workings to the surface because of the block caving.

Jan 1, 1960

By G. W. Murrie, W. P. Diamond, S. W. Lambert

A geologic study of the Mary Lee Group of coalbeds in the Black Warrior coal basin was undertaken to examine coal stratigraphy and determine regional trends and extent of the coalbeds. The area investigated encompasses 835 square miles in Jefferson, Walker, and Tuscaloosa Counties, Ala. More than 700 core logs were used to construct a structure map, coal, interval, and overburden isopachs, and cross sections. There is evidence that structure affected sedimentation. Coalbed isopachs indicate the Mary Lee Group was deposited in fluvial-deltaic and low-lying coastal plain environments. The Mary Lee coalbed is the only coalbed which is continuous throughout the area, commonly with two benches which have a combined thickness of 2 to 12 feet. The Mary Lee coalbed changes rank in the basin from high- through medium- to low-volatile coal. The methane gas potential of the Mary Lee Group coals is estimated to be greater than 1 trillion cubic feet. There is an excellent correlation between the orientation of surface cleats with those measured underground in the Mary Lee coalbed. The face cleats roughly parallel the axes of the area's folds and trend northeast-southwest.

Jan 1, 1976

Measure tattling in cemented backfill when installation of bore-hole extensometers is not feasible. Problem To evaluate the amount of load that backfill carries during pillar recovery, information about how much the backfill settles after placement is often required. However, the composition of some backfills makes them difficult to drill and the installation of borehole extensometers almost impossible. Approach Bureau researchers have developed a vertical fill extensometer that can be cast in place as a stope is being filled. It consists of a baseplate, sections of steel pipe enclosed in loosely coupled polyvinyl chloride (PVC) pipe, and a top anchor assembly that contains a displacement transducer (fig. 1).

Jan 1, 1990