Search Documents

By M. R. Geer, H. F. Yancey

"INTRODUCTION Throughout the history of coal washing, the jig has been one of the most important coal-cleaning appliances. In 1935 34.7 percent of the 45,361,021 tons of clean coal produced was the product of jigging. 4/ Previous to 1928, most of the jigs used in the United States were of the piston type, with which sufficient mobility to allow stratification in bed is imparted by the reciprocating up-and-down movement of a piston in the water compartment adjacent to the screen compartment. In 1928, the Baum type of jig was introduces in this country and has since come into wide spread use. In this type, water pulsations are imparted by application and release of compressed air to the water compartment. All prior studies of the mechanism of seperating cleared coal from impurity by piston-type jigs. 5/ The same laws of settling, of course, apply to both types, piston or Baum, but the character of the separation with the Baum type may be modified more easily because of the flexibility with which air may be handled, as distinguished from the fixed action of eccentrics commonly used in piston jigs. Since no detailed studies are available to show the performance, that is, the character of the separation between coal and impurity, of the Baum type the Bureau of Mines undertook the investigation recorded in this report."

Jan 1, 1938

By S. H. Ash

THIS REPORT covers the second in a series of five projects into which the Conowingo tunnel system has been divided for geographical and practical reasons. It outlines the construction work contemplated-to sink two shafts on the line of the main tunnel that are designated the Nos. 9A and 11 shafts, to turn off from the No. 9A shaft the Lansford and Lykens laterals, and to drive portions of the main tunnel. An emergency pumping plant, consisting of 2 separate pumprooms, each containing 3 horizontal-type centrifugal pumps of 100,000-gallons-per-minute (g. p. m.) capacity, will be constructed at the No. 9A shaft. From the No. 11 shaft will be turned off the Trevorton lateral and portions of the main tunnel, which will connect with the section driven from the No. 9A shaft. Under the proposed project, the Lansford lateral will be driven for a distance of 2 miles, the Lykens lateral for a distance of 10.56 miles, and the Trevorton lateral for a distance of 20 miles. To drive the Lykens and Trevorton laterals for the distance indicated, several construction shafts and slopes must be sunk to permit efficient and safe construction.

Jan 1, 1955

By W. F. Watts

This report describes a statistical analysis of 41,502 respirable quartz dust samples collected from 1974 through 1981 in metal and nonmetal mines and mills. The goal of this Bureau of Mines study was to identify commodities and occupations associated with high quartz dust exposure so that future enforcement and research activity can be focused on the high-exposure areas. For this analysis, the Bureau used its computerized Mine Inspection Data Analysis System (MIDAS), which contains data on nearly 350,000 air samples, including data for 61 contaminants in 45 commodities. The samples analyzed were collected by inspectors of the Mine Safety and Health Administration (MS HA). The data were entered into the MIDAS computer and coded according to commodity, occupation, location, and other categorical information. Occupations an. commodities with high quartz dust exposure were identified by grouping the data by code categories. Workers at sandstone, clay and shale, and miscellaneous nonmetallic mineral mills had the highest quartz dust exposures. Within these mills, occupations with high exposures were baggers, general laborers, and persons involved in crushing, grinding, and sizing operations. Dust concentrations in these mills were not necessarily the highest, but because the dust contained a high percentage of quartz, the health risk from dust exposure was the greatest.

Jan 1, 1984

By Irving Hartmann

The Experimental Coal Mine of the Bureau of Mines has served principally as a valuable and unique testing laboratory for studies of the explosibility of coal dust and mine gas; studies of the numerous complex and interrelated chemical and physical factors that govern the ignition of coal dust and the propagation of mine explosions; and studies designed to develop measures for preventing explosions or reducing their destructive effects. These researches, coupled with educational efforts by the Bureau of Mines and enlightened safety consciousness in the mining industry, had fruitful results. This is evidenced by the remarkable reduction in the frequency of major coal-mine explosions and the number of fatalities from explosions since the Bureau of Mines was established. Despite this progress, further important unresolved problems arise; these are due in part to changes in mining conditions and methods, which have brought about increased production of fine coal dust in highly mechanized operations. To solve the new problems, research must be continued without interruption. The results of many very recent and current studies in the Experimental Coal Mine are summarized briefly, and pertinent studies by European mine-safety-research organizations are listed.

Jan 1, 1957

By Robert E. Hershey

1. Estimates of reserves were made for three coal beds in Hamilton County the - Lantana, Sewanee, and Richland. Nine coal beds have been mined at one time or another in the county, but not enough information was available to estimate reserves in any beds other than the three given. 2. Known measured and indicated reserves for all beds, based on a minimum thickness of 14 inches and on 1,800 short tons per acre-foot of coal in place, are estimated to be 53 million tons as of January 1, 1954. Of this total 35 million tons is in beds 28 inches and more thick. Areas in each bed were omitted from the estimate because available data relative to the bed characteristics were insufficient for making an estimate conforming with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove re-serves in these areas, such reserves should be added to the total estimated reserves determined by this investigation.

Jan 1, 1956

By Gary L. Hundley

The Bureau of Mines has devised and demonstrated a process for recovering Ni and Co from low-grade domestic laterites. The process consists of four major steps: (1) reduction roast, (2) ammoniacal leach, (3) solvent extraction, and (4) electrowinning. Several solid-liquid separation steps are required that affect the economics of the overall pro-cess. In this study, two techniques for solid-liquid separation, centrifugation and thickening, were investigated. This report presents the results of (1) laboratory and pilot plant studies to determine parameters for sizing centrifuges and thickeners and (2) an economic study of the two techniques, based on the requirements of a commercial-size (5,OOO-tpd) laterite processing plant. Sizing and other equipment-related recommendations, based on data from the Bureau's studies, were obtained from commercial manufacturers. The costs of thickening and centrifugation, including all the unit operations affected, were determined by the Bureau's process evaluation group. The total operating costs ~or separation using the two techniques (including depreciation on the capital cost of equipment) were found to be quite close: $17.26 per ton of laterite for centrifugation and $18.15 per ton of laterite for thickening. For centrifugal separation, the greatest cost was found to be the initial capital cost for the separation equipment; using thickeners, the greatest cost was for re-agent recovery.

Jan 1, 1984

By R. E. Siemens, Gary L. Hundley

The Bureau of Mines has devised and demonstrated a process for recovering Ni and Co from low-grade domestic laterites . The process consists of four mmaajjoorr steps : ( 1 ) reduction roast , ( 2 ) ammoniacal leach , ( 3 ) solvent extraction , and ( 4 ) electrowinning . Several solid - liquid separation steps are required that affect the economics of the overall process . In this study , two techniques for solid - liquid separation , centrifugation and thickening , were investigated . This report presents the results of ( 1 ) laboratory and pilot plant studies to determine parameters for sizing centrifuges and thickeners and ( 2 ) an economic study of the two techniques , based on the requirements of a commercial - size ( 5,000 - tpd ) laterite processing plant . Sizing and other equipment - related recommendations , based on data from the Bureau's studies , were obtained from commercial manufacturers . The costs of thickening and centrifugation , including all the unit operations affected , were determined by the Bureau's process evaluation group . The total operating costs for separation using the two techniques ( including depreciation on the capital cost of equipment ) were found to be quite close : $ 17.26 per ton of laterite for centrifugation and $ 18.15 per ton of laterite for thickening . For centrifugal separation , the greatest cost was found to be the initial capital cost for the separation equipment ; using thickeners , the greatest cost was for reagent recovery .

Jan 1, 1983

By G. F. Skala

Additional testing of two prototype instruments for the discrete detec­tion of submicrometer particles in metal and nonmetal underground mines is described. The detectors are designed to utilize properties of submicrometer particles to distinguish between those produced by fires from mine ambient particles primarily resulting from diesel engine exhaust. One instrument is based on the ability to pyrolyze fire produced parti­cles, but not diesel exhaust particles. An alarm is produced when the ratio of pyrolyzed to unpyrolyzed particles exceeds a preset value. The other detector utilizes a continuous flow ion chamber preceded by a denuder to remove charged particles. Discrimination against diesel produced submicrometer particles results because the diesel particles are naturally more highly charged than fire produced particles. In-mine testing was conducted over a period of several months. Both in­struments exhibited an ability to discriminate against diesel exhaust. However, problems with the recording equipment, and with the instruments themselves, due to large ambient dust particles, prevented enough data from being obtained to choose between the two methods. Recommendations to correct the problems are made.

Jan 1, 1982

By C. B. Kenahan

A summary of Bureau of Mines research on recycling, reuse, and disposal of mineral-, metal-, and energy-based wastes is presented, accompanied by an extensive bibliography of related publications. The Bureau's waste recycling and disposal program is directed toward the following four main areas of research and development: (1) extraction of mineral, metal, and energy values from urban refuse; (2) upgrading and recycling of automotive and related ferrous and nonferrous scrap; (3) recovery, utilization, and stabilization of mine and mill processing wastes, and (4) recovery and reuse of values from industrial waste products. This publication updates Bureau of Mines Information Circular 8529, which was issued August 1971.

Jan 1, 1973

This manual provides instructions for installing, operating, and maintaining a protective canopy on the Joy Mfg. Co. shuttle car. These instructions are based upon actual installations made in the mine on two shuttle cars, model 21SC-2E. The parts list and engineering drawings for the protective canopy are included at the end of the manual. And a discussion of some alternative design concepts is also included. The manual can also be used for retrofitting other shuttle cars with similar protective canopies. Skilled mechanics can determine if the instructions hexein would he applicable to the other shuttle cars and can determine any necessary modifications if they are not.

Jan 1, 1973

Fresh coal refuse was sampled at 21 US mines. Five of the sites were drilled, sampled and tested more extensively. Field tests included Standard Penetration tests, and in-situ density determinations. Laboratory testing included specific gravity, gradation, maximum, and minimum density tests, as well as 9-inch) drained triaxial tests, 9 and 10-inch, permeability tests, slake-durability tests, and accelerated slaking tests. Some refuse sites had significantly lower shear strengths and permeabilities in old, slaked or weathered material than in fresh refuse. Testing did not show useful correlations between strength and permeability changes and other material properties which could serve as "predictors". Testing of refuse under "accelerated slaking" conditions showed promise as a comparative tool and as a potential means of preparing artificially aged samples for evaluations of long-term behavior. The state-of-the-art in slaking research, and the implications of slaking on coal refuse disposal, and on practical methods of managing slaking, were also studied.

Jan 1, 1981

By William E. Young

There are many large rhodunite-bearing veins containing manganese in the Eureka-Animas Forks area of the San Juan Mountains in Colorado. The Sunnyside vein is the largest known vein in the area. As observed on the surface, the vein is mineralized over 8,000 feet and attains a maximum width of 200 feet. The average width of the vein and its branches and ramifications is 58 feet in the area that was mapped in detail. The weighted-average analysis of surface and underground samples from the northeastern extension of the Sunnyside vein is 8 percent manganese. Most other known veins in the area have a similar manganese content. The Hidden Treasure vein lies southeast of the Sunnyside-No Name-Mastadon vein. The weighted average of the analyses of surface and underground samples from this vein is 13 percent manganese. Exposures of the Scotia-Silver Chord vein are visible over a strike length of 4,000 feet on Treasure Mountain. Diamond-drill holes show that the vein contains 10 percent or more manganese to a depth of 400 feet. The vein has an average width of 28 feet. The Independence vein is exposed on the surface for a distance of 600 feet and has an average width of 6 feet. Three cut samples taken across the vein had an average content of 20.7 percent manganese. Sampling of the outcrops of eight veins in the Placer Gulch area also indicates manganese. Numerous other veins cropping out in the surrounding area are similar to the outcrop of the. Sunnyside vein system mineralogically and are worth investigating.

Jan 1, 1966

By Carl Belser

Approximately 30 million pounds of tungsten trioxide in the form of ferberite concentrates have been shipped from Boulder County. Since 1940, the production has varied considerably, being affected by the emergency needs of World War II and the Korean conflict. During World War II, attempts to stimulate production were made by the Metals Reserve Company by stabilizing the price for a specified period, the Reconstruction Finance Corporation by small mining development loans, and the Bureau of Mines and the Geological Survey, who cooperatively explored some of the district by surface and underground core drilling. During the Korean conflict and continuing through the first half of 1954) tungsten production was being stimulated by a Government-gauranteed price and by financial assistance loans under the Defense Production Act of 1950 to qualified operators of properties that have merited exploration. This combined program has increased production in Boulder County from about 1,900 pounds in 1949 to an estimated 383,000 pounds of tungsten trioxide in 1953. The 1953 production came from 67 properties. One of the problems confronting producers is the need for improved beneficiaton methods. Ores from the area have not been amenable to flotation concentration and gravity methods have resulted in poor recovery, often less than 70 percent.

Jan 1, 1955

By William L. Crentz

This Investigation of the preparation characteristics of the coals in Armstrong County, Pa., is the third in a series of Bureau publications by counties appraising the practicability of upgrading marginal deposits to metallurgical standards. Earlier investigations covered the washing characteristics of the coals occurring in Cambria County, and the principal reserves remaining in Indiana County. In Armstrong County, the Upper Freeport bed is the major source of production, the Lower Kittanning bed being of secondary importance. The Lower Freeport bed is mined to some degree, but it is usually too thin and spotty in occurrence to support large-scale operations. The remaining production is taken from the Pittsburgh, Middle Kittanning, and Upper Kittanning beds, but the quantities are insignificant. Table 1 shows the county's coal production) by beds, during 1948. The coals of Armstrong County are not generally considered to be of metallurgical quality because of the high sulfur content. The raw coals usually analyze more than 2 percent sulfur, and more than 4 percent sulfur is not uncommon, especially in the Lower Kittanning bed.

Jan 1, 1951

By Elio Ferreira

This report describes the design, and development work performed to reduce the volume and weight of the miners caplamp battery, as well as a headpiece with a swivel mechanism containing a halogen bulb with two filaments. Work was also conducted in the development of a maintenance free battery. The design concept is based on non-sintered Ni-Cd technology, with an energy density of 22 Wh/lb. The cap lamp system developed has been approved by the Mine Safety and Health Administration (MSHA) and can be manufactured for mine use.

Jan 1, 1988

By J. M. Goris

The U.S. Bureau of Mines, in a cooperative project with the University of Utah, Salt Lake City, UT, and Homestake Mining Co., Lead, SD, conducted in situ monitoring and numerical modeling of rock masses supported with cable bolts in two mechanized, cut-and-fill stopes and a shaft pillar at the Homestake Mine. Extensometers were used to measure rock displacement, while cable bolt strain gauges were installed to measure loads on both conventional and birdcage cable bolt supports. These instruments provided an assessment of rock mass behavior during mining as well as essential data for verifying results from computer analyses. The numerical modeling program FLAC was used to analyze cable bolt patterns and supports. Results from the evaluation study indicated that cable bolt strain gauges and extensometers were effective instruments for monitoring the behavior of rock masses supported with cable bolts. Also, numerical modeling of the 4S-48N stope using the FIAC code provided displacement values comparable with measurements from field extensometers.

Jan 1, 1993

By L. F. Heising

The Bureau of Mines evaluated 191 composites from the central Mesabi Range, Minn., chiefly by reductive roasting and magnetic separation. After reductive roasting and magnetic separation at minus 325 mesh, 28 composites produced concentrates that contained an average of 66.0 percent iron with less than 10 percent silica. Recovery of contained iron was over 90 percent. Natural magnetic material in excess of 5 percent was present in 142 composites. Trial flotation tests were used to evaluate three samples unresponsive to reductive roasting and magnetic separation procedures, and satisfactory concentrates having low silica contents (averaging 6.6 percent) were achieved.

Jan 1, 1965

By Linneas W. Laage

MFIRE is a computer simulation program that performs normal ventilation network planning calculations, and dynamic transient state simulation of ventilation networks under a variety of conditions. The program is useful for the analysis of ventilation networks under thermal and mechanical influence. MFIRE simulates a mine's ventilation system and its response to altered ventilation parameters, external influences such as temperatures, and internal influences such as fires. Extensive output enables detailed quantitative analysis of the effects of the proposed alteration to the ventilation system Network simulation using digital computers has become widespread throughout the mining industry in recent years. However, as the sophistication of the simulator increases (MFIRE, for example), the complexity of input data requirements and interpretations of results requires more skill and knowledge from the users. Perhaps the most difficult part of using MFIRE is to construct the data set describing the mine's physical layout and its ventilation properties. The initial attempts to get the data set running often reveal unknown or ignored aspects of the mine's ventilation.

Jan 1, 1995

MFIRE is a computer simulation program that performs normal ventilation network planning calculations, and dynamic transient state simulation of ventilation networks under a variety of conditions. The program is useful for the analysis of ventilation networks under thermal and mechanical influence. MFIRE simulates a mine's ventilation system and its response to altered ventilation parameters, external influences such as temperatures, and internal influences such as fires. Extensive output enables detailed quantitative analysis of the effects of the proposed alteration to the ventilation system Network simulation using digital computers has become widespread throughout the mining industry in recent years. However, as the sophistication of the simulator increases (MFIRE, for example), the complexity of input data requirements and interpretations of results requires more skill and knowledge from the users. Perhaps the most difficult part of using MFIRE is to construct the data set describing the mine's physical layout and its ventilation properties. The initial attempts to get the data set running often reveal unknown or ignored aspects of the mine's ventilation. MFIRE was written in Fortran 77 and compiled with Microway1 Fortran for the Intel 80386 based computers with a 80387 math co-processor. The source code is portable and available for users who wish to modify the source code to operate on other computers. This user manual describes the development of MFIRE, the input format and requirements, the output, common errors, fire parameters, and examples MFIRE application. Valuable reference material is included in the appendices. Knowledgeable users may skip directly to the PROGRAM INSTALLATION AND OPERATION section to begin using MFIRE immediately.

Jan 1, 1995

MFIRE is a computer simulation program that performs normal ventilation network planning calculations, and dynamic transient state simulation of ventilation networks under a variety of conditions. The program is useful for the analysis of ventilation networks under thermal and mechanical influence. MFIRE simulates a mine's ventilation system and its response to altered ventilation parameters, external influences such as temperatures, and internal influences such as fires. Extensive output enables detailed quantitative analysis of the effects of the proposed alteration to the ventilation system Network simulation using digital computers has become widespread throughout the mining industry in recent years. However, as the sophistication of the simulator increases (MFIRE, for example), the complexity of input data requirements and interpretations of results requires more skill and knowledge from the users. Perhaps the most difficult part of using MFIRE is to construct the data set describing the mine's physical layout and its ventilation properties. The initial attempts to get the data set running often reveal unknown or ignored aspects of the mine's ventilation. MFIRE was written in Fortran 77 and compiled with Microway1 Fortran for the Intel 80386 based computers with a 80387 math co-processor. The source code is portable and available for users who wish to modify the source code to operate on other computers. This user manual describes the development of MFIRE, the input format and requirements, the output, common errors, fire parameters, and examples MFIRE application. Valuable reference material is included in the appendices. Knowledgeable users may skip directly to the PROGRAM INSTALLATION AND OPERATION section to begin using MFIRE immediately.

Jan 1, 1995