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By H. L. Gilbert

Improvements in production of high-purity chromium metal by magnesium reduction of anhydrous chlorides and by hydrogen treatment of electrolytic chromium are reported. Hydrogen-treated chromium has been arc-melted, and the arc-melted material has been successfully forged, rolled, and swaged. The material also has been forged at liquid-air temperatures. X-ray and metallographic studies indicate the recrystallization temperature of rolled chromium sheet to be about 750° C. Preliminary investigation of hot-bending characteristics of rolled chromium sheet shows the minimum bending temperature to be about 325° C. The heat resistance of chromium has been investigated.

Jan 1, 1952

By James P. Ulery

In This Chapter [Geologic features associated with anomalous methane emissions Gas outbursts and blowers Methane drainage strategies for mitigating anomalous methane emissions and General considerations for a methane drainage program] This chapter summarizes how certain geologic features may be associated with unexpected increases in gas emissions during coal mining. These unexpected emissions have the potential to create explosive conditions in the underground workplace. Also discussed are the generally used practices to alleviate potential hazards caused by gas emissions associated with these geologic features. INTRODUCTION Unforeseen mine gas emissions in quantities sufficient to create hazardous conditions have been attributed to sources outside the mined coalbed since the first documentation of methane explosions in coal mines [Payman and Statham 1930]. Geologic features such as faults have long been recognized as conduits for gas flow from strata adjacent to mined coalbeds [Moss 1927; Payman and Statham 1930]. Other features such as sandstone paleochannels, clay veins, and localized folding have also been recognized for their impact on gas emissions into mine work-ings [Darton 1915; Price and Headlee 1943; McCulloch et al. 1975; Ulery and Molinda 1984]. The fact that strata adjacent to mined coalbeds can emit large quantities of methane gas into mine workings is not surprising from a theoretical perspective. Many researchers have recognized that during the burial and diagenesis of the organic matter forming today’s minable coalbeds, similar dispersed organic matter in adjacent strata has produced methane in quantities far exceeding the storage capacity of the coal and surrounding rock [Juntgen and Klein 1975]. It is not surprising then that large quantities of methane can remain trapped in these strata. A potential hazard occurs when mining of a nearby coalbed causes pressure differentials and mining-induced fractures conducive to gas flow into the mine workings from these strata. This gas flow may be facilitated or temporarily impeded by the presence of geologic structures or anomalies.

Jan 6, 2006

The principle activities of the Explosives Research Laboratory from July 1, 1961 to June 30, 1962, are described briefly in part 1. Part 2 gives short abstracts of publications that appeared during fiscal year 1962; in general, the research reported in these publications antedates the report period. Part 3 gives the results of an investigation which, although too limited to warrant separate publication, merits presentation in some detail because of current interest in ammonium nitrate-fuel oil compositions.

Jan 1, 1964

By C. E. Wood

A special appropriation made by Congress in July 1940 provided funds for the investigation of methods for recovering manganese from low-grade [ ] domestic deposits. These funds were assigned to the United States Department of the Interior, Bureau of Mines. A committee, identified as the Technologic Committee on manganese of the National Research Council, National Academy of Sciences, was appointed to recommend the allocation of the funds for investigation of the more promising projects.

Jan 1, 1942

By C. E. Wood

A special appropriation made by Congress in July 1940 provided funds for the investigation of methods for recovering manganese from low-grade [ ] domestic deposits. These funds were assigned to the United States Department of the Interior, Bureau of Mines. A committee, identified as the Technologic Committee on Manganese of the National Research Council, National Academy of Sciences, was appointed to recommend the allocation of the funds for investigation of the more promising projects.

Jan 1, 1942

By H. E. Powell

A laboratory investigation was conducted by the Bureau of Mines to study the magnetic characteristics and to measure the magnetic susceptibility of the mineral siderite. All susceptibility measurements were made by the method of Gouy on powdered samples and at room temperature. Specific susceptibilities of samples from 15 different locations, domestic and foreign, were determined. Values ranged from 66 to 103 (10-6) cgs electromagnetic units. The relation of susceptibility to mineral composition is discussed in this report. The specific susceptibilities of 76 minerals are tabulated in an appendix.

Jan 1, 1963

By Robert H. Merrill

Several investigators have obtained solutions for the concentration of stress around circular, ovaloidal, elliptical, and rectangular holes in an elastic, isotropic, semiinfinite plate subjected to uniaxial and biaxial stress. These solutions are used to evaluate the changes in stress around openings immediately under the undercut normally used in conventional block caving operations. The evaluations are based on the assumption that a horizontal undercut removes most of the vertical component of a biaxial stress field. The location and magnitude of the significant changes in stress concentration around the opening are computed. Conditions under which the assumptions used in the evaluations may or may not be consistent with conditions around block caving mines are discussed, and examples of preferred opening shapes for a biaxial (hydrostatic) stress field are shown. This report is a summary of one phase of an investigation to establish design methods for the size and shape of mine openings used in block caving mining methods .

Jan 1, 1962

The Bureau of Mines conducted large-scale laboratory copper ore leaching tests to enable improving copper recovery from large dump-leaching operations. This was done by comparing leaching progress when copper was recovered from recycled leach liquor either by cementation or by solvent extraction. Copper was leached from 7-ton ore samples at room temperature using pH 2 ferric sulfate solutions. With are samples containing 11 percent minus 0.5-inch fines, no marked advantage in using either of the copper recovery methods was evident after 416 days of leaching. With ore containing 32 percent minus 0.5-inch fines, solvent extraction of copper was advantageous in that 60 percent of the copper was extracted after 568 days, whereas only 48 percent of the copper was extracted when cementation was used. Less acid was consumed during leaching when solvent extraction, rather than cementation, was used for copper recovery. Iron, contributed by cementation with scrap iron, plugged the ore bed containing 32 percent fines.

Jan 1, 1981

By Roger E. Burleigh

In June, 1989, the U.S. Bureau of Mines, undertook a 9-day evaluation of the tin resource potential of the Sleitat Mountain tin deposit. Significant tin-tungsten mineralization is associated with quartz-topaz-white mica-tourmaline greisen alteration of a multi-unit, 57 Ma, peraluminous, granite stock which intrudes Cretaceous Kuskokwim Group flysch deposits. The granite comprises marginal biotite-, intermediate biotite-muscovite-, and central zinnwaldite-granite units, interpreted as a zoned alteration system. Major vein mineralization is confined to two east-west-trending zones of steeply oriented tabular lenses of greisen interleaved with mildly altered granite. Cassiterite is the dominant ore mineral while arsenopyrite, loellingite, wolframite, pyrite, sphalerite, chalcopyrite, and bismuth-oxides are present in minor to trace amounts. The north and south greisen zones are estimated to contain an inferred resource of 128 to 212 million lbs Sn in 28.6 million st of mineralized rock. An 1,800-lb representative bulk sample contained 0.37% Sn, 0.04% W and 17 ppm Ag and is considered an average grade estimate for the deposit. Drill testing by Cominco Alaska Exploration indicates that substantial widths of high-grade tin mineralization are included within the lower grade disseminated mineralization. Depth of deposit erosion is substantial and there exists a high probability for placer tin deposits.

Jan 1, 1991

By Ronald Branstetter

Gaseous and particulate exhaust emissions from 20 diesel engines in service at five underground mines were measured with high accuracy instrumentation. The engines that were tested were checked for faults or maladjustments. The vehicle and engine maintenance organization was studied at each mine and an idealized maintenance program was devised. Faults were induced in a new diesel engine to determine their effect on the characteristics of the exhaust emissions. The results, conclusions and recommendations from this investigation are presented in this final report.

Jan 1, 1983

By H. F. Yancey

About 65 percent of the more than 400 million tons of coal produced annually in the United States is mechanically cleaned to remove the inorganic impurities before being sent to market. The impurities, principally shale and clay with some pyrite, average about 20 percent of the raw coal treated. Nearly 95 percent of the tonnage is treated by wet processes, in which water, suspensions of solids in water, or occasionally calcium chloride solutions are employed. Difference in density of coal and impurity is the basis of these processes. Of major importance in the separation is the competency of the impurities, that is, the resistance of the impurities to size disintegration in water. In general, the impurities are more resistant in geologically older coals or those in effect made older by metamorphism. If the impurities suffer reduction in particle size when immersed in water, the separation of organic from inorganic material becomes more difficult, Recently the Scientific Department of the National Goal Board (Great Britain) undertook fundamental research into the interaction of shale and water and also developed an empirical method of assessing shale breakdown or disintegration. 6

Jan 1, 1962

To improve communications between mine workings and surface locations during emergency situations and for administrative purposes. The Approach: Development of a device for interconnecting phone systems which permits two-way communication between a public telephone and a mine pagerphone by authorized personnel. How It Works: The system, developed by personnel at the Bureau's Pittsburgh (Pa.) Mining and Safety Research Center, makes connections between the public phone line and mine pagerphone line. As shown in Fig. 1., incoming calls are sensed by the ring detector (4) and the system "answers" the call electronically. To reach the pagerphone system, the caller inserts an audible tone of fixed frequency through the microphone of his telephone. This tone is produced by a miniature, pocket-carried tone generator and is detected by a tone recognition circuit (5). When this hap-pens, relay, switching, and logic circuitry (6) closes the connections between the two phone systems. Simultaneously, a page activator (9) places a DC paging voltage on the mine phone line.

Jan 1, 1974

By Vance G. Leak

Leaching of manganese from low-grade Minnesota ores was studied over the temperature range 25° to 225° C at atmospheric and elevated pressures to demonstrate that good recoveries of manganese could be achieved from unroasted ores using reagents available nearby. Various combinations of ore, pyrite, lignite derivatives, and sulfuric acid were tested on a small scale. Pyrite alone required the highest temperature to effect a good extraction, but the combination of pyrite, lignite char, and sulfuric acid solubilized 99 percent of the manganese after 30 minutes of reaction at 75° C.

Jan 1, 1971

By Harvey L. Pastan

The purpose of the investigation and analysis described in this report is to assess the data flow requirements that are required for remote supervisory control of a continuous mining system. Since these control concepts as applied to continuous underground mining are still in a formative stage at the present time during the first half of 1975, assumptions had to be made based upon engineering judgment as to what embodiment of mining machinery and control methodology seemed most feasible for achieving such a system. Based upon these assumptions and estimates of the control system's accuracy and response requirements, it was then possible to estimate the communication requirements for the assumed system configuration. 2. Approach The team members responsible for this study visited numerous coal mines to observe room and pillar mining operations in both high and low coal. The objective was to observe the methods of operating a variety of continuous mining machinery and haulage equipment with a view toward defining the problems to be overcome in the application of automation to the coal extraction process. Descriptive information concerning the mining equipment was obtained through contacts with the manufacturers. Conferences with Bureau of Mines personnel, equipment manufacturers and developers, and mine operators were held to explore the current thinking and developments being pursued toward automation and increasing both production and productivity.

Jan 1, 1975

By Mark S. Stagg

Blast-induced ground vibrations from surface coal mine, quarry, and construction blasting were measured and analyzed for frequency content and duration characteristics. Eighteen commercially available ground vibration measurement systems were evaluated in the field and laboratory for linearity, accuracy, and crosstalk. Buried, surface, and sandbagged transducer placement methods were compared, along with peak and vector-sum measurements. The recommended minimum frequency ranges for ground vibration instrumentation are 2 to 150 Hz for coal mine and quarry blasting, and 5 to 200 Hz for construction and excavation blasting. When higher or lower frequency vibrations are possible, as in construction blasting or for a quarry shot close to a residence, care should be taken to insure proper choices of instrumentation and vibration criteria. Several instruments operating in these ranges are available, and all but one of the seismographs tested fell within ±3-dB accuracy limits (+41 pct, -29 pct). Waveform recordings of all three ground vibration components are recommended as the peak amplitude and frequency may vary among the three. Peak or vector-sum readings are adequate if only amplitude levels are desired. The soil density matched box should be anchored or buried, particularly for high-frequency, high-amplitude construction blasting.

Jan 1, 1980

By R. Barany

This report contains the results of experimental work conducted by the Bureau of Mines to obtain the heats of formation at 298.15° K. of analcite, dehydrated analcite, lawsonite, anorthite, hexagonal anorthite, and leonhardite. Thermodynamic data for these minerals have applications in ceramics, extractive metallurgy, and particularly in geochemistry. Except for data on anorthite, no previous similar data existed. The present results will be a substantial aid in deriving the temperature-pressure-equilibrium relationships among these minerals. The heats of formation were determined by solution calorimetry, with hydrofluoric acid as the reaction medium. The results were expressed both in terms of the constituent oxides and in terms of the constituent elements. The heat of formation data were combined with related entropy values to obtain the free energies of formation at 298.15° K.

Jan 1, 1962

By Paul S. Goodman

Volume I This report presents the first national survey of miners' attitudes and opinions about their-work. The goal is to present attitudinal data that bears on coal production. Interviews were conducted in 26 mines with 2,000 miners. High levels of cooperation were exhibited by management, union and the employees. Data are presented about miners' attitudes about general aspects of their work such as pay, supervision, their jobs, etc. Another section of this report reviews opinions about specific aspects of work performance. Recommendations are presented.

Jan 1, 1985

By J. L. Kohler

This final report on Bureau of Mines Contract J0348005 presents the results of an investigation into the development of a Management Information System (MIS) for underground coal mines. The motivation for the research is the unrealized potential for increasing safety and productivity of the well developed mine monitoring system technology. The intent of this project was to examine the information issues, various design aspects of an integrated monitoring/MIS, and associated application concerns, such as the impact of this technology on safety. The work performed on this contract used mine ventilation as a prototypical example. The report is presented in five chapters and six appendices. In addition to the introduction and conclusions chapters, one chapter deals with ventilation MIS system requirements; another with the formulation of a knowledge-based expert system (KBES) structure to implement the integrated ventilation monitoring/MIS system, and one on the health and safety implications of the system. The appendices present details of the KBES system application with an example using a mine ventilation simulator (PSU/MVS). An important conclusion is that a KBES formulation of an integrated monitoring/ MIS for coal mine management is feasible and desirable.

Jan 1, 1986

By C. T. Baroch

The purpose of this report is to describe the design features and techniques used in operating a plant capable of producing about 1,500 pounds of titanium metal per day. The process used was based on the reduction of titanium tetrachloride with magnesium, a modification of what is generally known and spoken of as the Kroll process. Sponge metal crushed to melter's specifications was the end product of the operation as conducted. The report is divided into sections covering general plant layout and the major unit operations. These, in turn, are each divided into discussions of the equipment, operating procedures, and typical results. Descriptions are given in more detail than is generally expected of a technical report. During 1953 and 1954 over 130 engineers and businessmen, officially representing some 80 industrial, chemical, end engineering firms, visited the operating plant, and their questions, which indicated a serious interest in details, have served as a guide for the material contained in this report.

Jan 1, 1955

By Rudolf E. Greuer

This report contains the practical application of a computer program for the simulation of ventilation systems under the influence of mine fires and other emergencies on five hardrock mines. The introduction describes the need for such a program, its basic features, and the range of its applicability which is mainly a function of the available ventilation data. The second chapter discusses program modifications, whose necessity or desirability was, during the application, discovered. The following five chapters, which comprise the major portion of the report, give the detailed description of the program application on the five mines. For every one of the selected mines, the ventilation system, the source of the used ventilation data and their preparation for computer simulations are outlined. Based on data for the airflow distribution solely, fumes concentrations in the mines are calculated for several assumed fire locations. Based on data for airflow and pressure distributions, ventilation disturbances caused by fires as well as the resulting fumes concentrations and temperatures are determined. The consequences for escape routes and the possible means to keep them free of fumes are discussed. To investigate the capabilities of the program, other contaminant sources and other potentially dangerous ventilation factors, like fan failures and changed surface temperatures, are simulated also. The results of the calculations have been entered into ventilation plans which makes them easier to scrutinize. All significant computer printouts have been attached.

Jan 1, 1981