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By Hugh D. Pallister

Alabama probably has the most extensive deposits of high-grade flake graphite in the United States and was the largest producer during World War I. Therefore, with the outbreak of World War II, users of flake graphite turned again to Alabama to supply their requirements. Flake graphite is the most important ingredient contained in graphite crucibles used in melting crucible steel and special alloys essential for war purposes. Early in World War II the Army and Navy placed flake graphite on the list of critical war materials. During World War I, when the supply of Ceylon graphite (then in demand) was cut off, large quantities of flake graphite were produced in Alabama, and about 40 mills were built. Most of these were abandoned after the war when imports of the cheaper Madagascar flake (which gradually replaced Ceylon graphite) began to reach this country. With the beginning of World War II, the Madagascar supply was cut off', and consumers were again compelled to look to domestic sources for their supplies. They found only one small mill in operation, that of the Ceylon Graphite Co. in Coosa County, Ala. The Bureau of Mines made a preliminary examination of the Alabama flake graphite deposits in 1940. Samples were taken and tested at the Southern Experiment Station at Tuscaloosa.

Jan 1, 1948

By W. W. Adams

Because of insufficient funds for printing, the Bureau of Mines was unable to publish its annual bulletin covering accidents at metal mines in the United States for the year 1933. A brief mimeographed summary of the principal statistical data for that year was released to the public late in 1934. Since then reports for 1934 have been received from the mining companies, and in order to avoid further delay in releasing this information to the mining industry and others interested in the prevention of accidents in mining, statistics for both years are presented in this publication with a minimum of interpretation and comment. The fatal-accident rate for the metal and nonmetallic mines (excluding coal mines) of the United States was more favorable in 1933 than in any previous year since 1911, the first year for which the Bureau of Mines obtained reports from the operators. Further progress was made in 1934, when the fatality rate was even lower than that of 1933. On the other hand, the nonfatal-accident rate, which had reached its lowest level in 1932, increased in 1933 and increased further in 1934, although not to such an extent as to prevent the rate for either of those 2 years from being better than that for any year previous to r1931.

Jan 1, 1936

This section presents highlights of world economic and mineral industry performance in 1982, a year characterized by continued recession, and selected 1983 forecasts of economic indicators of importance to the mineral industry, some of which indicate a modest improvement in the economies of the United States and Western Europe. The U.S. Economy in 1982 In 1982 U.S. gross national product (GNP) in current dollars increased at a rate of 4 percent, but GNP adjusted for inflation (real GNP) declined at a rate of 1.8 percent. Yearend 1982 real GNP was at roughly the same level as in 1980 (table 1). Thus no growth in real terms had taken place in the United States during the 1980-82 period.

Jan 1, 1983

By George Markon

The rapid growth and development of the Soviet coal industry rank the U. S. S. R. with the United States among the leading coal-producing countries. The coal resources of the Soviet Union are among the largest in the world, although coal development has been hindered by the disadvantageous location of the coal deposits with respect to the major consuming centers. Although coal production in the U. S. S. R. reached a record high, the total energy output of mineral fuels in 1957 was still far below that of the United States because a significant part of Soviet coal output was lignites or lower rank coals. Although the Soviet coal industry soon may exceed that of the United States in tons produced, the energy equivalent of Soviet output will be considerably less because of the inclusion of a high percentage of lower rank coals. Energy sources in the United States also involve large quantities of oil and natural gas, whereas coal supplies most primary energy in the Soviet Union.

Jan 1, 1959

By Robert B. Hoekzema

This Bureau of Mines report describes the history, characteristics, distribution, and mineral development potential of 21 lode gold deposits in or near the Chugach National Forest (CNF), AK. It includes findings from a 4-yr (1979 to 1982) mineral evaluation of the CNF conducted by the Bureau and the U.S. Geological Survey (USGS). This evaluation, undertaken to provide the U.S. Forest Service with mineral resource data for use in making decisions on land use, included site-specific mapping and sampling of more than 200-lode gold deposits. The data presented here were compiled from the findings of this 4-yr evaluation and from existing literature. Fourteen of the 21 lode gold deposits described in this report contain a combined identified resource of 117,750 short tons (st) averaging 0.55 oz/st Au and 0.2 oz/st Ag. Two mineralized felsic dikes in the Summit Lake-Palmer Creek area contain a combined identified resource of 18 million st grading 0.02 oz/st Au and 0.16 oz/st Ag. Identified resources were not determined for the remaining five deposits because of a lack of information.

Jan 1, 1987

By M. J. Kirwan

[There have been large increases in the oil production and casing-head gas production of certain wells on the Quinn dome (northern part of the Lyons-Quinn field of Oklahoma) caused by large volumes of gas under high pressure entering Vie productive oil sand, The oil production of sore of the leases in this part of the field temporarily increased over 100 per cent within a few days after gas entered the oil sand among the leases that had the greatest increases in oil production wore those on which no gas wells were drilled but which were located up-elope on the structure in reference to gas wells on adjoining properties. It is conservatively estimated that 1,444,000,000, cubic feet of gas entered the productive oil sand and, up to January 1, 1924, caused an increase of about 950,000 barrels of oil from this sand. The casing-held gas volumes of a number of wells producing between 25,000 and 75,000 cubic feet of gas per day increased to several hundred thousand cubic feet and a few walls increased to nearly two million cubic feet per day after extraneous gas entered the oil sand from which the wells were producing.]

Jan 1, 1924

By Charles J. Cohen, Donald F. Reed

"INTRODUCTION AND ACKNOWLEDGMENTSThis report supplements a previous report on work done in this same area 4/ but covers only the period from November 1945 to November 1946. The project was established in 1943 to investigate magnetite deposits in the northwestern Adirondacks by geophysical surveying and diamond-drilling for the purpose of increasing iron production in the eastern United States.In its program of investigation of mineral deposits, the primary objective of the Bureau of Mines is the more effective utilization of our mineral resources, that they may make the greatest possible contribution to our national security and economy. The policy of the Bureau is to publish the facts developed by each project as soon as possible after its conclusion. Maps showing the detailed magnetic surveys of the deposits and anomalies discussed in this report are on open file at the offices of the Bureau of Mines, College Park, Md., and at the University of the State of New York in the office of the Director of the State Science Service, Educational Building, Albany, N. Y.The Mining Branch, Lowell B. Moon, chief, conducts preliminary exami¬nations, performs the actual investigations, and prepares the final report. The Metallurgical Branch, Oliver C. Ralston, chief, analyzes samples and performs beneficiation tests.The chemical analyses included in this report were made at the Eastern Experiment Station of the Bureau of Mines at College Park, Md., under, the general supervision of J. B. Zadra, chief, College Park Division, Metallurgical Branch, and the immediate direction of Dr. Alton Gabriel, in charge of the laboratory service unit."

Nov 1, 1947

By Glenn A. Hazen

This report presents a stress investigation of four coal pillars located under two depths of cover. Each coal pillar was instrumented with ten load cells designed to measure coal pressure during initial and secondary mining. The problem considered was one of uniform triaxial stress as a large coal pillar was loaded under a thick limestone bed. Special attention was given to pillar design procedure. Unconfined uniaxial compression tests were conducted for coal specimens 7/8 in., 2-1/8 in., 3 in., and 4 in. square with length to square side ratios of 1/2, 1, 1-1/2, and 2. Stress-strain curves were recorded. Six specimens were tested at each size. Results show that a coal pillar is composed of an inner zone which is highly loaded plus a region around its perimeter which has lost its elastic strength. The bearing capacity of a coal pillar consists of elastic and crushed coal response: The failure strengths have been determined and will be useful in coal recovery, mine design, and mine safety.

Jan 1, 1975

By C. B. Manula

Simulation continues to hold the spotlight among the Operations Research applications in the operational side of mining. One reason for this is the need to solve the many waiting line and storage problems common to the industry. A second reason for using simulation is the central requirement of retrospect testing. Acceptance of a model by management is more likely to depend on its tested performance rather than on the underlying validity aspects of the model itself. Mathematics have not been and may not be developed that will allow all desired system elements to be considered simultaneously. It is in this realm that simulation bridges the gap between theory and useful design procedures. One of the earliest published accounts of simulation at work in the coal industry is demonstrated by the application cf Monte Carlo methods to explore changes in future operating policies for an existing track system (Manula, 1963). By modifying certain control parameters, revision in design changes were evaluated in the computer rather than in the actual production section. A second application which has found wide use in practice is the VFI-OCR Face Simulator (Prelaz et al., 1968). The model developed here has the purpose of allowing the comparison of methods for room-and-pillar face operations end observing their effect on mining prior to actual installation. Proposed changes are tried in the model and the best of these are selected as a guide for better mire management: IBM's own simulation package, the System 360 General Purpose Simulator, has experienced heavy use in solving similar problems and other steady-state situations.

Jan 1, 1974

By A. B. Cecala

A cooperative research effort was established between the Tilden Mining Company LC, the United Steelworkers of America, and the National Institute for Occupational Safety and Health to lower respirable dust levels in an iron ore grinding and concentrator plant. This cooperative effort involved three field studies to evaluate different techniques to lower respirable dust levels. The greatest impact on lowering respirable dust concentrations throughout this facility was achieved through ventilation changes. The most significant improvement was realized by changing the ventilation profile throughout the entire facility. The ventilation to this grinding and concentrator facility was provided by approximately 40 roof fans operating in either the intake or exhaust mode. The operation of these fans was significantly changed in an attempt to pro-vide more of a directional flow pattern throughout the facility, as well as to more closely balance the intake and exhaust air volume. This change accounted for a 31 pct reduction in respirable dust levels in the primary grinding area of the mill. Another successful modification was to improve the sealing of a reclaim tunnel to the outside and by barricading the access point from the reclaim tunnel to the concentrator plant. This minimized the dust liberated in the conveyor tunnels from traveling through the reclaim tunnel and into the plant. These two modifications illustrate the impact that improvements in ventilation can have on lowering respirable dust concentrations in iron ore processing facilities.

By D. Harrington

The record of fatalities from mine explosions in the United States during the past 44 years has been the best in the history of the mining industry, despite the fact that the number of fatalities from this cause during the past fiscal year now is nearly double that of the previous year. During there 4 fiscal years, mine explosions have resulted in an average of 45.5 deaths per year, compared with an average of 153 deaths per year for the preceding 5 years; an average of 542 deaths per year for the 3 years 1907-1909, inclusive, and a yearly average of 265 deaths per year for the 20 years prior to 1929. Other types of mine accidents also have been reduced during this period, but not to the same degree or by as large a percentage as mine explosions. The fact that in this fiscal year ended June 30, 1937, electricity was responsible for 60 percent of the explosions and 85.5 percent of the fatalities resulting therefrom (see tables 3 and 4) is evidence that either mine operators are lax in providing proper electrical equipment or there is laxity in the upkeep and use of electricity in our mines and more particularly in our coal mines. Several large coal-producing States that in the Fast have had numerous disastrous explosions have been free from such disasters for continuous periods of as long as 8 years. The bituminous mines of Pennsylvania, one of the largest coal-producing States, give a good example of what can be done to prevent explosions. 'his State, with its large number of operating mines, many with very definite hazards from gas or dust or both, has had only two major explosions (resulting in 16 fatalities) during the past 7 years; this is a decidedly good record compared with any similar period in the past and when it is considered that during this period about 750,000,000 tons of coal have been produced. Other good records are: Tennessee, without a single fatality from explosions during the past 9 years; Alabama, with 6 fatalities during the past 7 years; Illinois, with no explosions during the past 4 years; and

Jan 1, 1938

By W. L. Cornell

The Missouri lead ores are the only domestic sources of cobalt presently being mined and processed for other materials. They represent the best short-term solution for meeting up to 13 pct of the Nation's strategic and critical cobalt needs from domestic sources. Presently, the cobalt is lost as an impurity in the copper, lead, and zinc concentrates and in the mill tailings because the technology to recover it with minium impact on present production does not exist. This paper presents results of research, built upon earlier Bureau of Mines laboratory research, to enumerate the problems encountered in cobalt recovery from the copper concentrate under actual mill conditions; to present alternative solutions to these problems; and finally, to describe the best available technology for cobalt recovery within the imposed constraints. Mineralogical analyses showed the cobalt present as a distinct mineral phase, predominately siegenite, amenable to a physical separation method such as froth flotation. Flotation was chosen for recovery because of easy adaptation by the mills. Unit processes of grinding, conditioning, and flotation were studied individually and in concert, and a series of continuous tests were run based on the parameters developed to obtain engineering data for subsequent economic analysis. Overall cobalt grades of 3.00 wt pct at a recovery of 64.0 pct were achieved.

Jan 1, 1987

By John P. Gooch

The Bureau of Mines wrote a computer program which calculates the saturation curves and condensation characteristics of gaseous mixtures consisting of binary organic vapor and air. The program employs an algorithm which assumes an equilibrium mechanism for condensation, and the degree of fractionation obtained is predicted on the basis of relative volatility. The program incorporates a feature which allows the user to examine the fractionation resulting from condensation as a function of the size of the temperature increments over which condensation is assumed to occur. If a single. temperature interval between the dewpoint of the mixture and the outlet temperature of the condenser is assumed for the calculation, the results obtained will be those resulting from a single equilibrium condensation. If the condensation is assumed to occur over a number of temperature increments, the results obtained will approach those predicted by the Rayleigh equation as the magnitude of the temperature increments approaches zero. The results from calculations performed on vapor mixtures from organic heavy liquid solutions used in beneficiating potash and brucite ores are presented. The liquids are solutions of dibromomethane in trichloroethylene or perchloroethylene. The results show the degree of liquid recovery which is possible by cooling mixtures of organic vapor in air. Compositions of the vapor range from 10 to 95 percent air, and assumed condenser exit temperatures range from 110° to 50° F.

Jan 1, 1971

By Gerald T. Homce

Accidental contact of overhead electrical power lines by mobile equipment is a leading cause of occupational fatalities in the United States, accounting for 20% of on-the-job electrocutions. Overhead electrical power line proximity warning devices (PWDs) are intended to warn personnel if mobile equipment moves within some preselected minimum distance of an energized overhead electrical power line. Two commercially available PWDs were tested at the National Institute for Occupational Safety and Health?s (NIOSH) Pittsburgh Research Laboratory (PRL). The objective of the tests was to document performance capabilities and limitations for these PWDs by identifying factors that can influence their operation. The two PWDs evaluated in this research are the SIGALARM Model 210 marketed by Allied Safety Systems, LLC, and the ASE Model 2100 from Allied Safety Engineering. Both of these devices operate by measuring the electric field present around energized power lines. The PWDs were installed on a government-owned 22-st (20-mt) rough terrain crane. A purpose-built test site used for this research at PRL allowed operation of the crane near a variety of power line configurations operating at up to 25 kV. Most of the tests involved positioning the crane adjacent to one or more overhead power lines, adjusting sensitivities of the PWDs to alarm when the crane boom was approximately 20 ft (6.1 m) from the power lines, swinging the crane boom toward the lines under a wide variety of test conditions, and finally, for each unique set of test conditions, documenting the deviation from 20 ft (6.1 m) for actual alarm activation. Test results show that several factors can adversely affect PWD performance. PWD alarm accuracy generally deteriorated when operating with a boom position significantly different than that used for the device?s last sensitivity adjustment. Another factor that can affect PWD performance is configuration of the overhead power line(s) involved. Accuracy of alarm activa­tion distances was best for simple single-circuit installations, but degraded for multiple circuits on the same poles. This degradation was slightly greater for installations with different voltage levels and/or a combination of vertical and horizontal conductor arrangements. Performance also degraded for crane operation between two intersecting power line installations, especially for intersecting lines at different voltages. An additional aspect of power line configuration shown to influence PWD accuracy was phase sequence on the power line circuit(s). Specific phase con­ductor arrangements and combinations, particularly in multiple circuit installations, resulted in either improved or degraded accuracy.

Jan 1, 2008

Minimize the effects of underground mine conveyor belt fires by developing methods to prevent automatic fire suppression system failures. The Problem Fire protection is achieved by prevention, early detection, and planned fire-fighting response. Automatic fire suppression systems are one form of planned fire-fighting response. When these systems are properly designed, installed, and maintained they can effectively control fires. Conveyor belt fires account for about 20% of underground coal mine fires. Fire protection requirements have been established for underground locations because of potential for start and spread of fire and the restricted personnel egress in a fire situation. Belt conveyor systems arc potentially dangerous because of the high fire incidence rate, high temperatures, dense smoke, toxic gases, and rapid flame-spread rate. While investigating the conveyor fire suppression problem, the Bureau identified automatic fire suppression system reliability as a potentially serious deficiency within the mining industry. Table 1 lists common failure modes fur three Fire suppression system types. This table summarizes findings of Mine Safety and Health Administration electrical inspectors responsible for inspection of belt protection automatic fire suppression systems. Batteries, contact points, control wires, and electric servocontrols are all prone to failure. Figure 1 shows rock-dust-contaminated relay contact points. This condition is dangerous because of the chance of intermittent failures, which might allow systems to pass annual functional testing, yet fail during actual fire emergencies.

Jan 1, 1989

By R. V. Ramani, K. V. K. Prasad, M. Swaminathan

"Engineering design involves, in addition to numerical calculations, considerable amount of expertise and judgement. The expertise and judgement is required to conceptualize and idealize the problem, select a suitable mathematical model for the problem and to interpret the model results in terms of stipulated design constraints. In recent years, knowledge based systems (KBS) have provided the capability to integrate the qualitative experiential and expert knowledge with ~he quantitative knowledge for improved analysis and design of systems. A possible KBS architecture for mine ventilation system design was discussed by Ramani and Prasad · (1987). The expert system (ES) component of the KBS supports the analysis and interpretation phases of the ventilation design process with an algorithmic program used for the solution of alternate designs. The purpose of this paper is to discuss the data and knowledge needs for developing such a system and a formal means of their representation on the computer. A number of ES shells were evaluated to explore possible development and delivery environments for the system. A brief summary of this evaluation is also provided.INTRODUCTIONLuxbacher and Ramani (1979) have discussed the design process of mine ventilation systems and have provided the interrelationships that exist between ventilation, strata control, drainage and material handling systems and mining methods. They have also outlined the importance of correct analysis of the problem, choice of the right solution method and a rigorous interpretation of the solutions. The expertise required for analysis and interpretation phases was identified as the key element in developing effective and efficient ventilation system designs. Such expertise is embedded in the right choice of questions to be asked of the user as well as in directing the user to a wide array of alternative methods that may satisfy the design requirements. With advances in artificial intelligence applications in recent years, particularly expert systems, the integration of expertise into traditional mine planning and design algorithms has been facilitated. These planning and design aids, employing the integration of numeric and symbolic logic and called coupled systems, are powerful tools for engineers to tap the benefits of experts (Kitzmiller and Kowalik, 1985; Fenves, 1985). The purpose of this paper is to discuss the means of representing knowledge for the design of mine ventilation systems through the use of a coupled system. The KBS is visualized as consisting of the following components:"

Jan 1, 1989

By C. Lorimer Colburn

"High explosives are generally shipped in stout wooden boxes of convenient size, which are much sought after by miners and others for miscellaneous uses after they are emptied. The management of most mines has no fixed policy for the disposal of used dynamite boxes and will allow any one to carry them away. Many dynamite boxes are nailed up in the mine buildings or underground to serve as shelves and cupboards. Some are used as receptacles for odds and ends, and others are used in taking samples.Although used explosives containers are so generally put to beneficial service, there is nevertheless an element of danger in their use. Dynamite boxes are particularly dangerous. Very often nitroglycerin exudes from the dynamite sticks and is absorbed by the wood of the box. Such boxes are dangerous because they are very explosive. Although a box that has not absorbed nitroglycerin is safe, yet there is always the danger that a person will get a box that is partly saturated.On account of this danger, all mining companies should use extreme care in giving away used explosives containers. Some one individual who is acquainted with explosives and their peculiarities should act as inspector for every container given away. This job may best be handled by the man in charge of the powder magazines. A box that shows any stain of nitroglycerin should be destroyed by fire. The other boxes that are free from nitroglycerin or dynamite can be used."

Jun 1, 1920

By C. M. Harrer

The location, features, qualities, and extent of iron occurrences and the associated resources--limestone and dolomite, bentonite, coal-lignite, petroleum and natural gas, power, and water--are evaluated. The results of pioneer beneficiation tests on South Dakota taconite are discussed. In addition, pertinent features of taconite development, cost factors, the Western and Central United States trade area and markets are reported. The State's production of iron ores until 1963 has been small and for purposes other than the manufacture of iron. This investigation disclosed the probability of large resources of taconite in Pennington and Lawrence Counties. The average iron content is 29 percent, and a 65-percent or better iron concentrate might be produced. Ample resources are available for mining and processing taconite. An investment of at least $26 million would be required for a plant capable of turning out 1 million tons of agglomerated iron concentrate per year. The feasibility of such an enterprise is indicated, but intensive investigation and research must be completed to justify such an investment.

Jan 1, 1966

By P. J. Dallimore

The Bureau of Mines has calculated general time-dependent solutions for radon diffusion from cylindrical and slab rock samples containing uniform radium distribution. Results have been obtained for several sets of boundary conditions. The method is suitable for determining the effective diffusion coefficient and the effective porosity for radon.

Jan 1, 1983

By Jr. Frost

Helium used as a tracer gas in petroleum reservoirs continues to show great promise as a new tool for the oil and gas industry, according to tests conducted jointly by the Bureau of Nines and The Pure Oil Co. in-the Cabin Creek field, Boone and Kanawha Counties, W. Va. Helium, when used as a, tracer gas, is mixed with natural gas being injected into a reservoir for secondary recovery of oil, recycling, pressure-maintenance, or other purposes. Three separate experimental helium tracer-gas tests were run in the Cabin Creek, W. Va., field, wherein helium was added as a tracer to the natural gas that was being injected into the oil-bearing Berea sandstone. The results obtained in each test permitted determining the direction and rate of travel of the injected gas, calculating the volume of injected gas in the gas produced at the various wells, and determining the nature of the transition from natural gas to injected gas during a gas-injection program. Data were obtained on the effects obtained from waves of injected gab containing 1 percent and containing 5 percent helium and from a wave of essentially pure helium injected into the formation.

Jan 1, 1950