Search Documents

By K. L. Erickson, Gerald A. Munson

"The need for spodumene as a source of lithia for war purposes led to the exploitation of the Edison pegmatite deposit 1-1/2 miles southeast of Keystone, S. Dak. The operation was conducted during 1943 and 1944 by the Lor Mining Co., Rapid City, S. Dak. Spodumene concentrates in the ratio of 15:1 were recovered by hand picking from a sorting belt. This method was expensive and wasteful of spodumene, owing to the small size of the crystals.Data4/ obtained by the Bureau of Mines indicates that blunging with hydroflouric acid or sodium hydroxide is a prerequisite to selective flotation. Results of tests by Denver Equipment Co., Denver, Colo., indicate that economic recoveries can be obtained in an alkaline circuit after desliming.At the request of the Lor Mining Co., K. L. Erickson, metallurgical engineer, was permitted to work in the pegmatite research laboratory to verify previous investigations and to determine problems that might be involved in commercial milling. The ensuing investigation indicated that electrolytes in the mill water produced a profound inhibiting action on the flotation of Edison spodumone.An investigation of mill water from various sources showed that some waters are suitable for the process and others are not. Subsequent testing showed that all of the available waters are suitable after treatment. The flotation of the Edison spodumene in an alkaline circuit after desliming and using oleic acid as collector is efficient and economical when the water does not contain impurities.In its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B.Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests. Both these branches arc under the supervision of Dr. R. S. Dean, assistant director.As the work was of a practical nature, samples from possible mill-water sources in the southern Black Hills were obtained, and commercial softening and demineralizing methods were investigated. Data on various waters tested are given in table 1."

Jun 1, 1946

By Fun-Den Wang

This report presents the results of two large scale field coal pillar strength tests (80 ft by 80 ft), the results of a series of laboratory small core sample tests, and the correlation between those field and laboratory tests. The concept of applying laboratory coal sample strength data to predict the in situ coal pillar strength appears to be feasible. The deformation property of large pillars can be obtained successfully by testing the coal sample in the laboratory within acceptable accuracy. There are prevailing directional strength and deformation properties in coal pillars along the butt and face cleat system.

Jan 1, 1976

By Steven J. Page

Longwall double-drum shearers frequently have difficulty complying with the 2.0 mg/m3 dust standard and, therefore, require the use of effective dust controls. However, before dust controls can be implemented effectively, the major individual dust sources must be determined and their relative severity evaluated. The Bureau of Mines has recently developed a sampling strategy, based upon short-term gravimetric sampling, that can identify the major dust sources contributing to the shearer operator's exposure. This technique utilizes approved gravimetric sampling equipment already available to all mine operators and can be performed by two people in 2 days. Five examples, including data analysis, are discussed with respect to various cutting sequences. In addition, typical dust source contributions obtained from studies of double-drum shearer operations regularly in compliance are included. Mine operators can thereby compare their dust source evaluation results with those from these longwalls.

Jan 1, 1982

By Mulligan John J.

The Bureau of Mines investigated lode tin deposits on Potato Mountain, Seward Peninsula, Alaska. Tin was found to occur as cassiterite associated with quartz, tourmaline, pyrite, arsenopyrite, and earthy clays, but the deposits lack the varied accessory minerals commonly found in tin districts. The tin-bearing deposits are in metasediments along minor breaks and bedding planes but not in the crushed earthy filling of major faults. Cassiterite and sulfides occur with quartz in veins, both with and without earthy clays, and disseminated through tourmalinized wall rocks. The deposits are characterized by irregular segregations containing 1 to 10 percent tin within zones averaging not over 0.25 percent tin. The largest segregation exposed is on the summit of a low hill on the east-central slopes of Little Potato Mountain; most of the outcroppings are in an area trending east to west, roughly 10 to 30 feet wide and 300 feet long. Sample values ranged as high as 12 percent tin, but the average grade may be about 1 percent tin. The extreme irregularity of both grade and composition precludes a more exact determination. Similar concentrations are scattered for over 1,000 feet to the west and north, but these are smaller and lower in grade. Elsewhere on Potato Mountain, generally similar deposits occur as clusters of veinlets at widely separated points in the metasedimentary walls of major faults.

Jan 1, 1965

Objective: To improve the effectiveness of dust collector capture on surface mine drills.

Oct 1, 2005

By J. G. Kirby

The total number of petroleum refineries in the United States decreased during 1951, while the total crude-oil charging capacity continued to increase. There were 350 refineries as of January 1, 1952, compared with 357 a year earlier, according to the annual Bureau of Mines capacity survey. A gain of 369,241 barrels in daily refinery crude through-put capacity during 1951 brings the total to 7,332,885 barrels daily. The capacity of the average refinery to process crude-oil was 20,951 barrels daily, an increase of 1,445 barrels daily over the previous year. Capacity added in the Texas Gulf district accounted for 36 percent of the total increase; the Indiana-Illinois-Kentucky district, 23 percent; the East Coast district, 19 percent; the Oklahoma-Kansas district, 12 percent; and the Texas Inland district, 11 percent. The California district was the only one reporting a decline in crude-oil refining capacity, the total being 14,200 barrels daily below the previous year. Reported as under construction January 1, 1952, was an additional crude-oil capacity of 282,680 barrels daily, an increase of 77 percent over the January 1, 1951, total of 160,100 barrels. The capacity now building is for the expansion of existing facilities, since no new plants had been begun as of the first of the year. Three or four companies have plans to build refineries in the Williston Basin area of North Dakota, but no definite locations or dates when construction will begin have been announced.

Jan 1, 1952

By D. B. Dow

This paper on the physical chemistry of oil-field emulsions is the last of a series of three prepared as a result of a study of oil-field emulsions. The first paper3 deals with the factors responsible for the formation of emulsions, find the second4 with methods now utilized for dehydrating oil-field emulsions. A more complete report of the whole investigation is in preparation. The laws governing the formation and resolution of oil-field emulsions fall in that branch of physical chemistry doling with colloids. Much work has been done by the physical chemist on colloids And emulsions, and, although most of this work was on commercial and pharmaceutical emulsions, yet the principles developed apply in a general gray to oil-field emulsions.

Jan 1, 1925

By R. S. Dean

The development of metallurgical processes may be divided into periods : First , the discovery of a basic reaction which brings about the production of the desired product from the available raw material ; second , a long stage of mechanical development during which little or no attention is paid to the reaction itself ; and third , a careful study of the reaction . Most metallurgical processes are to -day approaching the end of the second period . This we may illustrate by the steel process . The reaction of carbon with iron ore to produce pig iron and the subsequent refinement of the pig iron by an oxidation reaction is very old . Development in modern times has been almost entirely mechanical , the development of the blast furnace , furnace , the Bessemer process , the Siemens process , and even the Aston process for wrought iron being mechanical improvements almost entirely . Metallurgy is now entering a phase where the reactions are being considered . The question of how far can they be made to proceed is being repeatedly asked . As mechanical processes are improved , we approach a limit to which our basic reactions can be pushed which is determined by the nature of the reactions themselves . We want to know : How far can iron be decarbonized by iron oxide ? How low can the oxygen of copper be reduced by any given reaction? How efficiently can the fuel in a zinc reduction process be used ? The demand for purer metals and lower production costs has forced these and similar questions upon us . How are we to answer them ? The determination of these equilibria or end points of metallurgical reactions by direct means is fraught with difficulty because here we must overcome mechanical difficulties which too often become the limiting factors even in the laboratory and we do nottherefore get the actual limit to which the reaction itself may be carried . Further , there are so many reactions of metallurgical materials that to survey each separately is a job to give pause to any experimenter or group of experimenters .

Dec 1, 1930

By R. C. Buehl

An experimental iron blast furnace of 3-foot-diameter hearth, producing about 12 tons of metal per day, was operated for 2 weeks with various proportions of anthracite replacing a corresponding amount of coke. The furnace operated well with anthracite in amounts up to 40 percent of the total fuel and produced metal of uniformly low sulfur and normal silicon contents. An increase to 50 percent anthracite during two attempts resulted in poor operation and the charge hung in the s haft of the furnace. INTRODUCTION Anthracite production in Pennsylvania decreased from 84,400,000 net tons in 1926 to 40,600,000 net tons in 1952, and there was a further decline in 1953 to 30,900,000 net tons. Employment in the anthracite industry dropped from 165,000 men working an average of 244 days per year in 1926 to 57,900 working an average of 163 days per year in 1953,3/ which has naturally resulted in considerable unemployment in the region. The industry is actively engaged in promoting new uses for anthracite to increase the demand and thus improve economic conditions in the region. One possibility is the use of anthracite to replace part of the coke for smelting iron ore in blast furnaces. The tests in this report were made to determine whether this use of anthracite would be feasible.

Jan 1, 1955

This is the second of a series of reports on properties of commercial motor fuels made pursuant to a cooperative agreement between the Cooperative Fuel Research (C.F.R.) Committee and the Bureau of Mines of the Department of the Interior. The first report gave data oil motor gasolines sold during the minter of 1935-36.3/ These gasoline surveys report results of inspections, in oil-company laboratories, of samples of gasoline obtained by representatives of oil companies from service-station pumps in marketing areas throughout the country. In the present survey are presented inspection data on 239 samples of regular- price gasoline, 166 samples of premium-price gasoline, and 157 samples of third-grade gasoline, a total of 562 samples collected during the summer of 1936.

Jan 1, 1937

This is the second of a series of reports on properties of commercial motor fuels made pursuant to a cooperative agreement between the Cooperative Fuel Research (C.F.R.) Committee and the Bureau of Mines of the Department of the Interior. The first report gave data on motor gasolines sold during the winter of 1935-36.3/ These gasoline surveys report results of inspections, in oil-company laboratories, of samples of gasoline obtained by representatives of oil companies from service-station pumps in marketing areas throughout the country. In the present survey are presented inspection data on 239 samples of regular-price gasoline, 166 samples of premium-price gasoline, and 157 samples of third-grade gasoline, a total of 562 samples collected during the summer of 1936.

Jan 1, 1937

By Friedel. Michael J.

The U.S. Bureau of Mines investigated acoustic emission (AE) and the Kaiser effect in six types of rock: St. Cloud gray granodiorite, Barre granite, Dresser basalt, Salem limestone, Berea sandstone, and a volcanic tuff. AE signatures were used for interpreting the rock deformation stage and for indicating mechanisms of failure in uniaxial compression. The research demonstrated the advantages of using the volumetric stress-strain curve, as opposed to the more conventional uniaxial curve, for correlating AE response signatures with deformation stages and fracture processes in the rock. Standardized experimental procedures were used for the AE monitoring. The Kaiser effect was shown to be capable of determining prestress levels to within a few percentage points in uniaxial compression tests. Also, prestress memory was shown to be retained in the rock for periods of up to at least. 5 months, the maximum period of testing. The Kaiser effect AE technology holds promise for providing a comparatively inexpensive and less complex method for examihing stress history in rock. However, since the conftning stress has a pronounced influence on the Kaiser effect, it must be considered in developing technology for determining peak fteld stresses based on the Kaiser effect.

Jan 1, 1990

By Thomas J. Albin

This U.S. Bureau of Mines report identifies potential causes of slip-and-fall accidents occurring during surface mine equipment maintenance and describes the relative roles of direct worker behavior and machine design. The relative roles of human behavior and machine design in the causation of slip-and-fall accidents were determined through analysis of accident records, observations of maintenance worker behavior, and evaluation of mine machinery. From these data, relative risk ratios were calculated. Behavior had a relative risk ratio of 1.5; machine design, specifically access systems design, had a relative risk ratio of 2.2. Of the access systems, ladders had the highest relative risk ratio, 7.0. This study suggests that accident intervention would be most profitably made in improving the design of systems used to access maintenance worker areas of mining equipment.

Jan 1, 1990

By A. Wahab Khair, S. Jung

"This paper deals with the fracturing process of laterally confined blocks of coal subjected to impact indentation. During the test, blocks of coal with approximate dimensions of 10 in. x 10 in. x 6 in. were laterally confined to predetermined equivalent in-situ stresses and then subjected to an impact indentation by dropping coal cutting bits (various shapes) attached to a known weight from a known height. During the test a number of parameters, namely surface strains (using strain gages), penetration depth (using L.V.D.T.) and acoustic emission characteristics were measured. After the test, the fractured surfaces were photographed with the aid of a camera attached to a microscope. The fracture, its intensity and extended zone within the coal blocks were mapped using sonic techniques. By correlating measured parameters, fractured zones under a given set of test parameters were identified and characterized.INTRODUCTION To improve the understanding of basic failure mechanisms in coal cutting, a better knowledge of fracture and crack regions caused by the indentation in coal is needed. This study reports the detailed experimental procedure used in fracture analysis of indentation experiments on coal specimens using the Acoustic Emission (A.E. hereafter) and sonic techniques. The relationship between microcracking and the inelastic deformation of rock was confirmed by a series of experiments in which the A. E. generated by the cracking in the rock specimen were recorded and the number of events were compared to the strain measurement. (Scholz, 1967).According to fracture mechanism theory, crack initiation in brittle materials such as rocks begins from ""flaws"" either pre-existing or induced by the indentation process itself. Rocks are pervaded by natural cracks and pores, from which numerous possibilities for crack initiation arise (Lindquist, Lai and Alm, 1984)."

Jan 1, 1989

By M. J. Ankeny

This is a study of 58 fatal haulage accidents investigated by Federal coal-mine inspectors during the period January - June 1951. The information presented in this circular was obtained by analyzing fatal haulage accidents in 33 bituminous-coal producing counties representing 11 States. The physical conditions represent a cross section off producing coal beds. Mining and transportation methods vary, from those of small hand-loading mines to those of large modern mechanized operations. These data are thought to be representative of haulage conditions within the bituminous-coal mining industry and are submitted to follow up the Information Circular 7604 ?Analysis of Haulage Fatalities in Bituminous-Coal Mines - 1950.? Coal-mine haulage ranks second as a cause of coal-mine fatalities, and the problem of haulage safety is complex. It is subject to constant change and is comprised of numerous influencing variables, which are not always obvious. The solution to this problem will not come through the application of any standard formula or mechanical approach since the inherent factors are strongly influenced by the human equation, and the chain of circumstances is further affected by expediency.

Jan 1, 1951

By Thomas C. Atchison

The experimental work described in this report is part of a continuing study by the Federal Bureau of Mines of the fundamental physical processes involved in breaking rock with explosives. Six explosives were tested for their strain-producing abilities in a dolomitic marble. The explosives selected for testing had a tenfold variation in detonation pressure and a fivefold variation in characteristic impedance (product of loading density and rate of detonation). Strain pulses produced by the detonation of small charges of the explosives were recorded at distances of 5 to 130 feet. Peak strain, ?, was found to decrease with distance, R, in accordance with an exponential propagation law previously determined for other rock types, namely ? = (K/R)e ?aR The absorption constant, a, did not vary significantly with the explosive and was of the same order of magnitude as that for other rock types. The different explosives produced a fivefold variation in the value of the intercept constant, K.

Jan 1, 1961

This Information Circular from the National Institute for Occupational Safety and Health (NIOSH) documents and supplements the information presented in a series of workshops held during 2002 and 2003. The primary intended audience consists of all who are involved in developing and conducting miners' training. According to the Mine Safety and Health Administration (MSHA), mine operators reported 240,000 full-time equivalent workers and independent contractors reported 42,000 full-time equivalent workers working on mine property during the year 2000. Unfortunately, these workers have a relatively high risk of suffering serious work-related injuries and illnesses. The mining industry has the highest rate of occupational fatalities among all U.S. industries. The fatality rate is 30 deaths per 100,000 workers compared to 4.6 for all private industry (Morbidity and Mortality Week Report, 2001; NIOSH, 2002). Compared to workers in other industries, miners also have a relatively high rate of nonfatal lost-time injuries, and their injuries tend to be more severe (Bureau of Labor Statistics, 1999). Many miners are also exposed to significant health hazards, including coal and silica dust, diesel exhaust, and noise. More than 1000 U.S. miners die of lung disease each year (NIOSH, 1999). Mine safety and health professionals have long recognized training as a critical element of an effective safety and health program. Federal regulations (30 CFR, Parts 46 and 48) require mine operators to provide initial safety and health training to all new miners, as well as a minimum of 8 hours of refresher training each year. The time and money being spent to train U.S. miners is substantial, and so there is a strong and steady demand for new and better mine training materials and methods. A growing concern among mine safety professionals regards the training of new workers. A major change in the mining workforce is anticipated within the next decade. In major segments of mining, especially coal, relatively few workers have been hired since the 1970's. Thus, as an entire cohort of miners in the current workforce nears retirement, the replacement of these employees will require an influx of new workers. New miners may be young people who lack the ability to recognize and respond to mining hazards in an appropriate manner. They may also have had different educational experiences than their older counterparts. Many safety professionals believe that these two cohorts require different approaches to training. The papers in this report should help prepare mine trainers for the changes about to occur in the workforce and acquaint them with strategies they can use to enhance the effectiveness of their training. The first three papers present basic principles for teaching adults. The five remaining papers are intended to illustrate how these principles can be applied to the development and imple¬mentation of effective training for miners. Below is an overview of these papers. 1. Kowalski and Vaught review the process and principles of adult learning. The learning model they present includes a discussion of goals, content, delivery, assessment, and remediation. Adults are viewed as active learners, experienced-based, expert in their own right in specific areas, independent, real-life centered, task-centered, problem-centered, solution-driven, skill-seeking, self-directing, and internally and externally motivated. Basic aspects of curriculum development are briefly reviewed. For further information about adult learning, see Camm and Cullen's paper. 2. Mallett and Reinke's first paper discusses issues related to training new miners who have recently or will soon be entering the mining workforce. These new generations of miners have different learning style preferences and training needs than Baby Boomers and other older miners. Even trainers who have been highly effective in the past should reassess their training styles and their classroom materials to determine if they are prepared to meet the needs of these young new workers. This paper provides information that will help mine trainers communicate across the generation gap. 3. Mallett and Reinke's second paper provide an overview of training evaluation. Trainers and decision-makers are given a framework for planning and assessing training evaluation strategies. The authors present Kirkpatrick's (2001) model of evaluation categories and discuss how to start an evaluation plan and various ways to collect data. They do not provide detailed instruction in evaluation methodologies, but give trainers a review of the things they need to consider when developing an evaluation plan. A good evaluation plan can inform revisions to a training course, assess trainee learning, and/or answer managers' questions about program effectiveness. 4. Brnich, Derick, Mallett, and Vaught discuss a technique for incorporating worker participation into fire prevention and safe equipment operation training. This technique involves development of short (5 to 7 minutes) videotapes coupled with toolbox talks that ground the content of the videos within the context of a miner's workplace. An example of one of these training modules is presented, along with the results of an evaluation performed on its effectiveness at improving miners' understanding of what types of information they should be sure to communicate during a mine emergency. 5. Wiehagen, Conrad, Friend, and Rethi discuss on-the-job training (OJT) as a method for teaching miners safety and production skills. Much of the training is done by experienced workers. This paper describes how small investments can help improve the effectiveness of on-the-job training. Effective on-the-job training involves some structure and planning in the transfer of responsibility for task performance from the trainer to the novice. Assisting the trainer could involve helping develop up-to-date job analyses and offering strategies for teaching and evaluating job skills. This paper addresses organizational considerations supporting structured on-the-job

Jan 1, 2002

By Grace N. Broderick

U.S. supply and demand data for coal, by States and regions, were tabulated for the years 1960 and 1965. Estimates are provided of State-by-State quantitative data for the coal industry that can be integrated into State and regional energy balances by source, form, and consumer sectors, and used for estimates of interstate and interregional energy flows. The tables give an estimated total supply of coal available for consumption, and also report the distribution of the supply among the major consuming sectors (household and, commercial, industrial, transportation, and electricity generation). To enable comparison of coal data with those for other energy forms, tonnages were converted to British thermal units (Btu). Future energy analysis studies could be facilitated by changes in the categorization of information collected on the coal industry. The data shown are based primarily on Bureau of Mines source material.

Jan 1, 1969

By Lloyd A. Morley

Two methods are presented to determine the mechanical shaft torque as a function of time for an induction motor. The methods are based on the motor equivalent circuit and use as input variables of the motor terminal voltage, line current, input power, and power factor. One method uses all four variables and the other uses only voltage and current. The test data deals specifically with continuous miners, but the theory could be applied to other mining machines driven by multiple induction motors. Results are given for the tramming, maneuvering, cutting, and cutting with loading operations and are in the form of a minimum, a maximum, and an average of the shaft-torque time function. The theoretical development and computer implementation are discussed for both methods.

Jan 1, 1978

By M. F. Boos

The Portland beryl-mica district, Middlesex County, Conn., comprises three deposits investigated by the Bureau of Mines in 1943. The Gotta-Walden deposit is in a pegmatite dike 4 to 20 feet thick, which cuts gneiss and schist. In general, the hanging wall is rich in mica and beryl with some feldspar, quartz, and garnet. The central core is usually high in quartz and feldspar, with relatively little mica and beryl. The footwall comprises quartz and feldspar, with varying amounts of mica and some beryl. The beryl crystals range in color from green to almost golden and have a maximum diameter of inches. Results of surface trenches indicate a beryl content of 0.81 percent for the pegmatite. A small production of beryl, feldspar, and scrap mica has been made from the deposit.

Jan 1, 1949