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By Russel Bohn

The purpose of this study was to evaluate the various techniques far mine roadway dust control. This evaluation included (a) the types of dust suppressants available, (b) the interaction of these products with the properties of the roadway surface, and (c) the costs and performance measures of the predominantly used dust suppressants. Over 30 products were identified having a wide range of effectiveness depending largely on the properties of the road base, subsurface, and wearing surface. The effectiveness of a dust suppressant was also found to depend on the application and maintenance procedures employed. As a result of this investigation five dust suppressants were identified s being predominant in the surface mining industry: Coherex, wetting agents, lignin sulfonate, water, and calcium chloride: An approximate cost-effectiveness analysis, limited by the lack of quantitative field performance data, showed that the five suppressants ranked in the order given above, with water being one of the least cost effective. This report also presents an analysis of applicable federal and state regulations.

Jan 1, 1981

Airy kind of a power system is a complicated network of various electrical components, such as cables, transformers, electric machines, circuit breakers, etc. For a system to work continuously and efficiently, each of the components has to be in perfect operating condition. The failure of any of these components can cause serious interruption of the supply and may in several cases involve a lot of precious time and labor in removing and replacing the damaged equipment it may also give rise to dangerous overvoltages on the system, thereby causing a safety hazard. Any piece of electrical equipment can have two likely modes of failure. The first would be the degradation of solid insulation material due to overheating, mechanical damage or a combination of the two, In this mode of failure it is possible that If the insulation damage is not an instantaneous phenomenon (a cable damaged by severe mechanical, Stress) that a detectable leakage current will do lop prior to the faint. The fault would probably he a result of heating and deterioration of the insulation by the leakage current.

Jan 1, 1975

By H. M. Cooper

Many analysts have had difficulty in obtaining accurate and consistent determinations of the volatile matter in low-temperature coke when the usual standard method for coal was followed. The tendency is toward too-high results, due to mechanical losses which are extremely difficult to avoid or control. With cokes there also may be an error due to excessive oxidation of the fixed carbon. Much of the earlier experimental work on the volatile-matter determination in coal, such as that of Parr,5 Fieldner and Davis,6 and others, 7 has been on the effect of time, temperatures, shape and size of crucibles, method of applying heat, and type of furnace, all of which data has evolved the present A.S. T. M.8 standard method for volatile matter in coal and coke. It is not the purpose of this investigation to deal directly with the above phases of the procedure, but rather to study some of the factors affecting she results in those types of fuel which give erroneous results due to mechanical losses.

Jan 1, 1932

By B. Gillenwater

This report describes the results of investigations into four specific areas related to trolley wire power distribution systems in coal mines. These are: 1. Partially insulated (shielded) trolley wire 2. High-speed insulator fault detectors 3. Dual-wire trolley systems 4. Insulator failure indicators. Prototype devices or designs were developed in each area. In addition, a brief survey was made in an attempt to assess the Future of mine trolley systems, and data was collected and reviewed in an attempt to analyze the nature of trolley wire related accidents. Other options for decreasing the risks associated with trolley systems that arose .during the study are briefly described in appendices. These include insulating equipment and miners from return and/or energized conductors and use of a segmented trolley wire with local control of current delivering capability.

Jan 1, 1981

By Laird Crocker

A goal of the Federal Bureau of Mines is to minimize the undersirable environmental conflicts and impacts associated with mineral processing operations. To help reach this goal the Bureau operated a citrate-process pilot plant for the removal of sulfur dioxide from lead smelter sintering machine waste gases to test the process. The process uses a carboxylate solution such as citric acid to absorb sulfur dioxide from waste gases. The absorbed sulfur dioxide is subsequently reacted with hydrogen sulfide to precipitate sulfur and regenerate the solution for recycle. Nominal capacity of the pilot plant was 1,000 scfm of 0.5 vol-pct sulfur dioxide gas. The pilot plant was operated for over 5,400 hr and produced about 55 net tons of sulfur. The operation demonstrated that (1) 99 pct of the sulfur dioxide could be removed from lead smelter sintering machining waste gases containing from 0.1 to 0.6 vol-pct sulfur dioxide, (2) sulfur precipitation and solution regeneration with hydrogen sulfide in conventional stirred vessels was readily controlled, (3) precipitated sulfur could be continuously recovered as a 99.S-pct-pure product by flotation and melting, and (4) 78 dry-vol-pct hydrogen sulfide gas could be produced from pilot-plant product sulfur, natural gas, and steam.

Jan 1, 1979

By Ivor Hawkes

This report describes the results of a study to evaluate new design concepts for percussive rock drills that will result in quieter machines. It is shown that by incorporating such features as an efficient muffler, a plenum chamber integral with the machine body, and shroud tubes around the drill rods, etc., noise levels are reduced from about 114 dBA to about 95 dBA with very little change in drilling performance.

Jan 1, 1977

By L. H. Banning

This investigation was undertaken to obtain basic information necessary for the design and operation of a plant for recovering metallic values from nickeliferous laterite and serpentine of the Philippine Islands. It was divided into three parts: (1) Mineralogical studies and preliminary mineral dressing tests; (2) electric smelting of the ores, upgrading of ferronickel by blowing with oxygen, smelting laterite slag to produce crude iron, and the production of mild steel; and (3) nickel and cobalt recovery from upgraded ferronickel. Results of the investigation indicate that it should be feasible to recover nickel, iron, and possibly cobalt products from the laterite and ferro-nickel from the serpentine. Mineralogical studies were made on representative fractions of the laterite and serpentine tonnage samples and on five selected samples; mineral dressing tests were made only on laterite. The nickel occurs principally associated with hydrous iron oxides and chemically combined with serpentine; garnierite was the only discrete nickel mineral identified, and it was found in a highly decomposed serpentine. The bulk of the cobalt was found in wadlike manganese oxide material. Approximately twice as much chromite was found in the laterite as in the serpentine, By mineral dressing techniques, laterite was separated into two fractions: one fraction contained over 90 percent of the nickel and cobalt, and 83 percent of the iron; the other fraction contained 74 percent of the chromium. A cobalt concentrate (1.1 percent Co) was produced by a scrubbing and sizing procedure.

Jan 1, 1962

By James J. Dowd

The investigation to evaluate the reserves of coking coal in the United States suitable for the manufacture of metallurgical coke is being made by the Bureau of Mines in three parts: (1) To estimate known (measured plus indicated) recoverable reserves of all coking coal; (2) to upgrade marginal coals through effective preparation; and (3) to study the carbonizing properties of coals and coal blends not now widely used for metallurgical coke making. This is the sixth of a series of reports giving the results of studies by counties under part (1) of the investigation. (See appendix.) This report covers Fayette County, Pa., which comprises the Uniontown and parts of the Brownsville, Connellsville, Donegal, Waynesburg, Masontown, and Confluence, Pa., Morgantown and Bruceton, W. Va., and Accident, Md., quadrangles. (See fig. 1.) A short resume of the chemical and carbonizing properties of the coals ar.9 included. Data on the coal beds in this county were obtained from mining companies, land companies, individual landowners, and other sources of authentic information.

Jan 1, 1951

By E. J. Gleim

An important phase in the Bureau of Mines investigation of electrical machines designed for operation in gassy coal mines is testing enclosures of electrical components for explosion-proof qualities. In brief, this testing consists of filling and surrounding the enclosure with an explosive atmosphere of methane and air and then igniting the atmosphere within the enclosure to determine (1) Whether the resulting explosion is confined without discharge of flame; (2) whether the enclosure walls are permanently distorted; and (3) whether excessive pressures are developed within the enclosure. Ordinarily, the pressures encountered in routine testing do not exceed 100 pounds per square inch gage. Hence, the designer of the machine does not have too much difficulty in taking corrective measures to prevent flame discharge and distortion of the enclosure. Occasionally, however, the explosion pressures greatly exceed 100 pounds. Then the goblet of the designer may not be solved so readily, From experience over the year 0, the testing personnel often can predict that certain construction will result in high. Pressures, but, only in a very general way, has it been possible to advise designers what modifications might be made to reduce the explosion pressures to normal values. For example, if high pressures were developed in a motor starter having a partition with an opening through it, some enlargement of the opening may appear to be the logical procedure, but it has not been- possible to give information concerning the exact amount the opening should be enlarged to prevent development of high pressures .

Jan 1, 1952

By H. E. Peterson

Rhenium occurs in very small quantities (12).4 In order for the Federal Bureau of Mines to conduct an investigation of rhenium sources and methods of extraction, it was necessary to devise improved techniques for detecting and measuring minute quantities of the metal. A modification of the procedure of Malouf and White (46) was developed which can be used to detect rhenium in concentrations as small as 0.1 part per million and can be used to measure quantities of 1.0 part per million. It can be used for the analysis of siliceous and calcareous ores, of molybdenite concentrates, of fumes, of flue dusts, and of other metallurgical products. Development of the method involved devising an amine extraction procedure for separating rhenium from all interfering elements except tungsten and a selective distillation procedure for separating rhenium from tungsten. Adoption of these separation procedures permits use of large samples and precise determination of rhenium by colorimetric analysis of the thiocyanate complex of rhenium by means of a spectrophotometer.

Jan 1, 1961

By S. P. Kinney, P. H. Royster, T. L. Joseph

"The study described in this paper, on the reactions in an iron blast furnace, is part of the investigation being conducted by the Bureau of Mines on combustion of coke and the reduction of iron oxides in the blast furnace. Previous study of the combustion zone of the iron blast furnace, by means of a series of as samples taken through the tuyeres across the hearths of 13 blast furnaces, showed that the combustion of the coke in the blast-furnace hearth is complete at a distance of 32 to 40 inches from the nose of the tuyere, measured horizontally toward the center of the furnace. The results of this previous work are sum¬marized in the curves shown in figure 1, where it will be noted that practically all of the oxygen disappears at a distance of approximately 30 inches from the nose of the tuyere.In order to determine the height at which oxygen is found in a vertical direction above the tuyeres - it had been suggested that the combustion zone turned upward near the tuyere and to obtain comparisons with the samples taken at the Bureau of Mines experimental6 (5-ton) blast-furnace at Minneapolis, the Bureau extended the gas sampling on a commercial furnace to a number of planes between the tuyere level and the stock line. The sampling was conducted on a 300-ton furnace, making foundry iron, operated by the Central Iron and Coal Co., at Holt, Ala. The furnace was smelting Southern red and brown ores and nodules from pyrite sinter. Figure 3 is a vertical section of the furnace showing the six planes sampled."

Apr 1, 1926

By R. V. Ramani

This volume is the first of a four-volume final report on research carried out under a contract from the U.S. Bureau of Mines on the development of a computer simulation model for surface mine reclamation planning. The other volumes are titled as follows: Volume II: Dragline Model, Volume III: Mine Coordinate Generator System, and Volume IV: User's Manual for OPMHS/2. This report deals with the development of a geological model for surface mine planning. The most common orebody modeling techniques are described. A brief review of geostatistical theory and concepts is presented. A geostatistical option for orebody modeling is developed and validated. Computer programs and sample outputs are appended.

Jan 1, 1985

By M. G. Wallis

This report presents the results of a study to develop a detailed mining method design based on longwall mining with sublevel caving. The method is applicable to low-dipping coal seams 20 or more feet thick such as are found in the western United States. The report covers (1) the development and description of the mining method, (2) evaluation of the engineering feasibility of the design, (3) estimates of productivity and recovery, and (4) an engineering cost analysis and economic feasibility evaluation of the mining method design.

Jan 1, 1977

By L. C. IlsLey

Cooperation between the United States Bureau of Mines and the Safety in Mines Research Board of Great Britain, continuous since 1924, has made possible this and other papers on safety subjects. Grateful acknowledgment is made to representatives of the Safety in Mines Research Board of the Mines Department for their assistance in arranging visits to several mine safety stations, and to F. R. Wynne, Deputy Chief Inspector of Mines, Great Britain, for arranging visits to mines in Great Britain, Belgium, Germany, and France. During the summer of 1927 the writer had the privilege of visiting the mine safety testing stations in Great Britain, Belgium, Germany, and France, in the order named. All of these countries have large coal mines, many of which are rated as gassy. Therefore, when installation of electrical equipment is contemplated, each of these countries is confronted with the same safety problem as is the United States - the development of electrical equipment that will not ignite gassy mine atmospheres which might, through neglect or accident surround the equipment. The means used by these countries in safeguarding gassy mines should therefore be of general interest to safety engineers of American coal mines, and it is proposed to give a brief survey for each of the four countries mentioned. This paper presents the second of these surveys, which covers conditions in Belgium.

Jan 1, 1929

By Martin Smirlock

A novel instrumentation system has been developed which enables simple, quick, and accurate measurement of vehicular dynamics within low speed ranges. The system, consisting of a microwave transceiver and microprocessor data acquisition and reduction system, measures the deceleration dynamics of low-speed mining and construction equipment. It makes the basic measurement, calculates key parameters such as average deceleration, initial velocity, stopping distance, and brake system delay time, and produces autoscaled graphs of velocity, acceleration, and displacement versus time.

Jan 1, 1981

By Gerald P. Scanlan

Control of the dust produced by continuous mining machines in coal mines is generally obtained by water sprays from fixed nozzles mounted on the frame of the machine in back of the cutting head. Mounting the nozzles on the rotating head of the machine closer to the coal cutting bits may improve the efficiency of dust suppression. To test this concept, respirable dust measurements were made during 39 regular production shifts in an underground mine using a Joy 11CM continuous miner. The equipment used, difficulties encountered, and measurements obtained are described.

Jan 1, 1974

By Alfred Petrick

This report analyzes the byproducts systems of lead, zinc, uranium, rare earths, iron, aluminum, titanium, and lithium. Specific byproduct metals covered are cadmium, germanium, indium, and thallium from the zinc system; antimony and bismuth from the lead system; vanadium, radium, and scandium from the uranium system; rare-earth oxides from the rare-earth system; and cobalt, gallium hafnium, and rubidium from other systems. The report discusses various metallurgical systems, marginal and incremental production costs of byproduct subsystems, industry structure and organization, and historical data on price, consumption, and supply.

Jan 1, 1973

By Kim B. Shedd

The U.S. Bureau of Mines Particulate Mineralogy Unit examined the habits of six zeolite minerals commonly occurring in domestic zeolite deposits. Mineral habit is of interest because current theory on the potential for sarcoma production in test animals emphasizes the size and shape of mineral particles, without regard to composition or structure. A scanning electron microscopic study revealed that, of these six minerals, only mordenite and erionite crystallized in acicular to fibrous habits, The fibrous varieties of these two minerals were characterized by size and shape on the transmission electron microscope, and their dimensions were compared with those of asbestos and amphibole cleavage fragments. When comminuted, these two minerals possess "fibrosity indices" similar to those of amphibole cleavage fragments. One sample, a rare woolly erionite, has uniform widths, large aspect ratios, and a "fibrosity index" similar to those of asbestos.

Jan 1, 1982

By Jonathan E. Ludlow

A field test was conducted to demonstrate and quantify the relationship between deep cutting and the creation of airborne respirable dust for longwall mining With a double-ended ranging drum shearer. The testing program was carried out on the 3 North longwall of North American Coal Company's Quarto No. y mine in Claringten, Ohio. Continuous recordings of the dust levels were made at both the midface and tail ate areas. Data were collected during 27 shifts during which time 81 complete mining, cycles took place. Both drum speed and the number of picks per line were varied systematically during the testing program to alter the depth of cut while the production rate was held constant by maintaining a constant haulage speed. The test results indicated that at the midface position, airborne respirable dust was strongly dependent upon the depth of cut as influenced by both the drum speed and number of picks. Drum speed had a much stronger effect than number of picks over the experimental range, since a halving of drum speed reduced dust levels by approximately 60 percent while removal of every other vane pick resulted in only a 2.1 percent reduction at constant production. At the tailgate position, however, neither effect was strongly apparent. A tendency for the slower drum speeds to he associated with reduced power consumption and higher haulage speeds (and therefore production rates) was also noted. It is recommended that longwall operators oper¬ate at the lowest available drum speed wherever possible.

Jan 1, 1981

By James W. Reil

A test series of small, precisely-controlled and thoroughly-monitored production blasts was conducted at two quarries. In each series, all variables except delay were kept constant, as much as practically possible. The first aim of the study was to determine the effect of local geology on ground vibration. The second aim was to test several hypotheses relating the effect of millisecond delay intervals to fragmentation and ground vibration. A resonant frequency of ground vibration was shown to be related to the thickness of the overburden, in accord with a model proposed by Gupta (1961). Since the overburden geology creating this resonant vibration cannot usually be changed, two methods were tested to choose delays such that blast vibrations would destructively interfere. These were shown to be effective in modifying both the peak particle velocity and response spectra of ground vibration. The delay interval chosen also affects fragmentation, primarily in massive rock, with an optimum relief between holes of 2 ms/ft. Strain gage records indicate a possible mechanism consistent with this information.

Jan 1, 1985