Search Documents

By J. Kruttschnitt

This paper, describing milling practice at Mount Ira Minis, is one of a series covering milling methods and cost that is being published by the Bureau of Mines, United States Department of the Interior. The Mount Isa concentrator began operations in day 1931 by treating a mixture of oxidized and sulfide ores. Since March 1935 only sulfide ores have been milled; this change involved major alterations to the flow sheet. The maximum capacity on mixed oxide and sulfide ores was 2,650 tons per day; the present capacity is approximately 1,880 tons of sulfide ore per day. The installation of additional crushing, grinding, and flotation equipment when completed early in 1939 will increase the maximum capacity of the concentrator to 2,240 tons of sulfide ore daily.

Jan 1, 1939

By Piyush K. Dutta

This report describes the design, development and manufacture of a prototype quiet hard rock stoper drill and results of its field tests. It is shown that the stoper drill noise level can be reduced from 118 dBA to below 100 dBA by using this design. The design concept of this drill is based on a valveless independent rotation system, use of an integral muffler and pivot mount. The drill was manufactured in a standard commercial drill manufacturing setup and organization. The design and production technology proved that commercially viable quiet drills can be made available for mine use.

Jan 1, 1985

By Mark Colwell, Christopher Mark

This paper summarises the results of a research project whose goal was to provide the Australian coal industry with a rib support design methodology and software tool that could be utilised by suitably qualified colliery staff. The project was primarily funded by Australian Coal Association Research Program (ACARP) and further supported by several Australian longwall operations. The outcome of the project is a design methodology and software tool called, Analysis and Design of Rib Support (ADRS). ADRS is an empirical technique, which recognises that several geotechnical and design factors affect ribline performance and in addition that operational and safety issues essentially dictate the level of performance required. Therefore, the design recommendations associated with ADRS are specific to the Australian coal industry; however the procedure(s) for data collection and analysis could be applied to other countries' 'underground coal industries. Case history data were compiled from 34 longwall and two bord and pillar operations resulting in 204 case histories with each case history data set being defined by approximately 130 individual data fields. In addition monitoring (incorporating stress cells and extensometers) was undertaken at 10 collieries to assess and quantify the effectiveness of different rib support patterns and hardware on rib performance. The monitoring sites allowed for an improved understanding of the mechanisms of rib failure and degradation in terms of its interaction with the installed support and at the various stages of the mining cycle. The design methodology deals with both mains development and gateroad development specific to Australian longwall mines. This paper focuses on longwall gateroads subjected to abutment loading and in particular the travel road which becomes the tailgate of the subsequent panel. The statistical analyses associated with these cases suggested that the level of rib support should be based primarily on the development height and the pillar stress level. The ADRS software guides users through the design process, allowing them to develop rib support plans based on sound science and a broad base of in-mine experience To the best of the authors’ knowledge ADRS is the first systematic rib support design technique to be developed for any country’s underground coal industry. The development and use of empirical models in mining have substantially contributed to improving safety and productivity. ADRS further demonstrates that empirical techniques are particularly relevant and beneficial in dealing with the complexities of geotechnical design associated with underground coal mining.

Jan 6, 2008

By D. F. Hambley

This manual contains a step-by-step procedure for the design of ore passes for open pit mines. The manual is comprehensive and deals with all aspects including location, design, construction and operating considerations. In the construction section, all applicable raising and shaft sinking methods are considered and cost estimates and advance rates provided for each. The design process is divided into several sections - rock flow requirements, support design, dump point design and draw point design. Use of this manual provides open pit planning engineers with a means of designing and assessing the feasibility of ore passes for their operations.

Jan 1, 1983

By C. W. Owings, J. J. Forbes

"Although coal-mine explosions rank third among causes of underground fatalities, they receive more wide-spread attention than any other accidents in mines because frequently many persons lose their lives in a single disaster. Each bituminous coal-mine explosion endangers the lives of approximately 100 persons--the average number employed underground in a commercial mine. A critical analysis of coal-mine explosions in a restricted district gives a cross-section of relative existing explosion hazards, of common causes of ignitions of gas and dust, and of effective prevention measures. The Safety Division of the United States Bureau of Mines is collecting data on coal-mine explosions in the various States, and this circular is one of a series analyzing the causes and recommending methods for thy prevention of similar occurrences,The data on this circular are based on records of the United States Bureau of Mines and the West Virginia Department of Mines. Unfortunately practically all of the early records were destroyed by fire in the State House at Charleston, W. Va.; the remaining records were made available to the authors by N. P. Rhinehart, chief of the Department of Mines, and his cooperation is gratefully acknowledged.The earliest available reference to coal in West Virginia is that made by John Peter Lally who in 1742 found ""a great plenty of coals"" near a river later called Coal River. In 1809, Nicholas Roosevelt found coal along the Ohio River and used it on the New Orleans, said to have been the first steamboat west of the Allegheny Mountains. In 1810, Conrad Cotts opened a mine near Wheeling and sold coal for domestic purpose in 1812, a mine was opened on the Ohio River opposite Mason City and produced 1,200 bushels of coal that year. In 1840 the total West Virginia coal production was 298,691 tons; in 1863, the production had increased to 444,468 tons, and in 1883, to 2,335,833 tons. During this period apparently most of the coal was extracted from coal outcropping on the hillsides; little danger of gas ignition existed at that time, but explosions from blown-out shots occurred frequently. On February 22, 1383 the West Virginia legislature enacted legislation providing for a mine inspector to inspect the mines of that State, to prevent mine accidents, and to insure properly ventilated mines.In a special report to the Governor on December 31, 1884 the Inspector of Mines reported:We have 5 shafts, in 4 of which there is more or less gas; and in 1 of our drift mines there was an explosion on the 27th day of March 1880, whereby 2 men were killed and a boy badly burned.Table 1 lists 287 explosions in West Virginia coal mines. Several early explosions were listed in the annual reports of the West Virginia Department of Mines as ""blown-out shots"" or ""powder explosions"". The injuries usually were described; explosives accidents have been eliminated from these and other available data, and only those in which dust or gas were involved have been included in this paper as explosions."

Sep 1, 1934

By Dennis J. Grigal

The goal of the program is to develop a dust collector system mounted on a ranging drum or arm shearer which will: 1) reduce the respirable dust level of the shearer operator by at least 75 percent; 2) be easily and economically mounted on an existing shearer; and 3) will not, through modifications to the shearer, reduce its safety or productive capability. The development program consists of three phases covering the activities of the design of the dust collector system, fabricating and installing it on the ranging arm or drum shearer, and conducting underground field tests on the modified mining machine.

Jan 1, 1980

By Thomas J. Peters

In 1985, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied a 17,320-acre portion of the 52,143-acre Little High Rock Canyon Wilderness Study Area (CA-020-913/NV-020-008) in order to evaluate its identified mineral resources. The study area is located in Humboldt and Washoe Counties, NV, about 42 miles north from Gerlach. Three areas of epithermal alteration, similar to alteration associated with disseminated gold deposits, were found in the study area. One of the areas occurs along a northeast-trending structural lineament. Southwest of the study area two gold prospects undergoing active exploration, as well JS a gold deposit being prepared for production, occur along the same lineament. The Bureau of Mines examination, however, did not find evidence for gold resources in the study area.

Jan 1, 1987

By B. W. Dunning

This paper describes studies conducted by the Bureau of Mines to achieve its goal of developing methods for increased recovery and utilization of valuable constituents in a wide variety of domestic and industrial wastes, In this particular study, 36 units of obsolete electronic equipment from military aircraft were disassembled into their modular components by hand to determine materials distribution. Further modular disassembly into individual parts was used to identify metal composition. After identifying the metals in some of the more difficult to dismantle modules, similar modules were grouped together, shredded, mechanically separated, and using metal composition data from hand separation, classified along with the hand-separated materials. Although this equipment is normally classified as law-value iron-bearing aluminum, data were obtained that indicated the potential for moderately higher value classification. The electronic units were classified as to precious metals, copper, iron, and aluminum contents, and scrap values were estimated.

Jan 1, 1980

By Doyle A. Ellerbruch

An FM-CW microwave system was investigated for measuring coal layer thickness. Measurements were made in three different mines near Pittsburgh, Pennsylvania, near Fairview, West Virginia, and near Coffeen, Illinois. Microwave frequencies in the range 1-2 GHz were used to measure samples up to 55 cm thick. All samples were backed with a naturally occurring shale. Measurements were also made on coal and shale samples compounded in the laboratory at the Bureau of Mines Pittsburgh Mining and Safety Research Center near Bruceton, Pennsylvania. The results indicate that layer thickness can be determined in most cases, although large anomalies may, in some cases, produce misleading results. Many anomalies that were detected with the FM-CW system were verified visually by drilling into the coal layer. The dielectric constant of coal apparently varies significantly within a coal seam. The form of the output signals from the FM-CW system seem to simplify the data interpretation and analysis process as compared to the manually swept microwave system used previously. It appears that this technique has the potential of measuring changes in the dielectric constant of a coal seam and providing an output that can be used for real-time corrections in layer thickness; measurement.

Jan 1, 1976

By R. E. Brewer

A critical review of the numerous test methods that have been devised for measuring the "plastic" and "swelling" properties of bituminous coking coals and the practical evaluation of the data obtained has long been needed. The author appreciates fully, first, the arduous problem of doing justice to the merits and limitations of the many original test methods and their manifold modifications and, second, the more difficult task of interpreting the test data obtained in their practical applications to the important problems involved in the coking process. It has been the constant aim of the author to point out the broader significance of the test principles employed in the different classes of test methods and the usefulness of the test data obtained in relation to the problem of coking bituminous coals, rather than to stimulate unduly a controversial criticism of the merits and limitations of any particular class of test methods or of individual test methods devised by different workers. The task has been quite difficult because of the almost total lack of accepted test standards and specifications.

Jan 1, 1942

By John L. Schaller

The Bureau of Mines, U.S. Department of the Interior, has investigated the extraction of alumina from domestic kaolin clay by leaching with boiling 26 wt-pct hydrochloric acid. Acid leaching of crushed calcined kaolin feed yields slurries that are slow settling and difficult to filter because of the presence of fine particles generated in crushing, calcining, and leaching. Laboratory research showed that tumbling and moistening crushed raw kaolin on a pelletizing disk caused the fines to agglomerate on the surfaces of the larger particles, while the sharp edges and corners of the larger particles were rounded off. Minus 16-mesh crushed raw kaolin was misted on a 36-in-diam, 8-in-deep pelletizing disk at rates of 175 to 250 lb/hr, and was calcined in either a rotary or a fluidized-bed calciner; negligible degradation occurred. The physical properties of the misted calcined kaolin were evaluated in the leaching system of the clay-hydrochloric acid miniplant. Only minor attrition occurred during leaching, and the slurry was readily filtered on a continuous belt filter.

Jan 1, 1982

By McHenry Mosier

The Bureau of Mines, United States Department of the Interior, has established a testing adit on the Government reservation at Mount Weather, Virginia, to facility to research on the fundamental tats of mining under actual metal-mining conditions. A number of sites in several Eastern States were investigated, out Mount Weather was selected because the rock seemed best suited for rock drilling and other mining tests and because the ground was already owned by the Federal Government, the site having been acquired in 1902 for use of the Weather Bureau. The testing edit has an advantage over en active metal mine for certain investigations because variable conditions affecting any particular research problem can be controlled and maintained in a fixed status, whereas in an operating mine this seldom is feasible. Operations were begin September 1935, with a crew of four laborers under a resident engineer. The laborers were recruited from, nearby farms, and. although they had no previous mining experience, they have developed into satisfactory miners.

Jan 1, 1939

By P. S. Haury

"INTRODUCTION Many ore deposits were discovered in the Wallapai Mining District, which covers the Cerbat Range in Mohave County, Ariz., during the early period of mining there from about 1865 to the 1890's. A considerable amount of production was obtained from shallow lead carbonate ores that carried considerable gold and silver.Mining was revived in 1906 and again during the First World War, and soma of the mines were deepened into the underlying sulfide zone. Substantial quantities of metal were recovered from two mines, the Golconda and the Tennessee-Schuylkill, that were, developed to depths of 1,600 and 1,400 feet, respectively. The Golconda is credited with $6,500,000 gross productions. 2/ This mine was not operated after 1917. The Tennessee-Schuylkill is still operating after a yield of about 300,000 tons of ore that averaged 4.33 percent lead and 7.74 percent zinc and contained an appreciable amount of gold and silver.Many of the old mines were reopened in 1942 or 1943 under the stimulus of premium prices for lead and zinc. A large proportion of this work was finished with loans from the Reconstruction Finance Corporation. It was believed that a good deal of lead and zinc could be recovered from the mines if a custom mill for concentration of the ores was available locally."

Aug 1, 1947

By Graham W. Marks, Betsy M. Jones

"Recently4/ it was shown that the total energy method5/ of spectrochemical analysis is suitable for the quantitative estimation of many of the elements of which ores are composed. It was shown how this method can be applied to the determination of germanium, tin, and lead. Continuing this work, the present report deals with analyses for beryllium, zinc, cadmium, and indium.There are three basic problems in these investigations. The first is to study the influence of those elements that make up the greater part of an ore sample on the spectral-line intensities of the elements for which analyses are being made, the latter generally being the minor constituents. The second is to develop proper methods for the preparation of standard spectrographic curves. Finally, we are concerned with improvement in equipment and procedure, so that greater accuracy can be achieved.As discussed previously, it is better to study as groups those elements that belong to the same group in the periodic table because their spectra are similar. Beryllium, zinc, and cadmium are thus related. Indium was included in this work because it is associated with zinc and cadmium in zinc ores.The authors wish to acknowledge the valuable assistance of the staff of the Bureau of Mines Analytical Laboratory who made the chemical analyses and supplied the ore samples used in this work.A brief description of the procedures followed in making the standard curves and analyses is given below; a detailed discussion will be found in an earlier paper.6/Basically, the procedure for determining a standard curve consists of two parts: (1) Choosing a suitable line in the spectrum of the element to be determined and (2) determining the variation in the intensity of this line with the amount of the element burned in the arc."

Nov 1, 1948

By Charles P. Lazzara, Alex C. Smith, Richard W. Pro, Mark W. Ryan

The U.S. Bureau of Mines conducted a study to determine if commercially available automatic sprinklers could withstand the high static pressures in deep underground coal mines without leaking and if exposure to the mine environment affected their leak pressures. New sprinklers and sprinklers exposed to the mine environment were subjected to increasing pressures until leakage occurred. The average leak pressures of the new sprinklers ranged from 640 to 2,300 psig and were significantly different for sprinklers from different manufacturers and for different types of sprinklers. Different for sprinklers from different manufacturers and for different types of sprinklers. Generally, standard-response sprinklers withstood higher pressures than fast-response sprinklers. The results indicated that most commercially available sprinklers would withstand the high static pressures in deep underground coal mines; however, they would not provide the same reliability and safety factor as sprinklers used aboveground at or below their rated pressure of 175 psig. The average leak pressures of the sprinklers exposed to the mine environment ranged from 740 to 1,180 psig. The mine environment affected the ability of 66% of the sprinklers to withstand high static pressure New sprinklers were also evaluated at pressures of at least 500 psig for 30 days to determine their ability to withstand long-term exposure to high static pressures; no leakage was observed.

Jan 1, 1993

Case 1: A driller raised a drill rig mast into a 7200-volt overhead power line. Both he and his helper were killed. Case 2: A driller-helper was pulling a winch cable toward a stack of drill steel when the cable contacted a 12,000-volt power line. The helper was killed, and the driller at the rig controls was severely injured. [ ]

Jan 1, 2006

By Terry S. Cory

This report covers magnetic field strength measurements vs range and frequency In low-medium coal mines. Both quasi-conductor-free and conductor-proximity areas were Investigated. The program covered 5 mines, 4 seams, 6 measurement sets, and 3 geographic areas, The results have been summarized In terms of maximum communication range expected per seam and noise condition. Scatter gain Is further explored as a simple measure of energy coupled to conductors.

Jan 1, 1978

By Eric E. Cather

In 1984 and 1986, at the request of the U.S. Forest Service, the U.S. Bureau of Mines conducted a mineral appraisal of the 315,000-acre Lemhi Range study area. This area is located in Lemhi and Custer Counties, about 25 mi south of Salmon, Idaho, and is in the Northern Rocky Mountain physiographic province, Topography is generally rugged with elevations ranging from 5,600 ft to about 11,350 ft above sea level. Since the 1880's, approximately 500 mining claims have been located within the study area; about 400 were current at the time of this investigation. Also, part or all of 12 patented mining claims are in the study area. During Bureau field work, forty-four mineralized sites were examined. The sites had been explored by 80 adits, 14 shafts, and about 140 pits and trenches. At least five properties in the study area have had significant production; the adjacent Mohawk, Grace Phelan, and Snowbird claims had a combined total of 136,000 oz of silver and 67,000 lb of lead; production at the Brown Bull was about 14,800 oz of silver and 115,000 lb of lead; the Portland mine yielded an unrecorded amount of silver. The Hilltop mine, located a few hundred feet outside the study area, produced 125,000 oz of silver, 2.7 million lb of lead, 87,000 lb of zinc, and 62,000 lb of copper from mineralized zones that might extend into the study area. More than 10,000 lb of copper were produced at the Blue Jay mine from workings located about 1,000 ft outside the study area. The Bureau of Mines investigation did not reveal the presence of identified resources in the study area. However, several areas contain mineralized sites and are known occurrences. Some of these warrant additional work to further delineate the mineralization and possibly determine identified resources.

Jan 1, 1988

By Russell G. Warncke

"This report is based primarily on a study of safety conditions and practices followed in the coal mines of Japan. Not all of the coal fields in Japan were studied, but typical mines in the largest producing areas and a fair cross section of coal-mine-safety conditions observed during February to April 1948 are described.Information was obtained through investigations conducted in the mines, discussions with mine-management officials and representatives of labor unions of the various mines visited, and examination of records and statistics from the various offices of the Coal Board of the Ministry of Commerce and Industry and from the Coal Association of Japan. Statistical data covering the same subject, obtained from different sources, varied in many respects and apparently were reported inaccurately, but such discrepancies can be attributed to different methods of reporting and compiling statistics.It is difficult to correlate the high fatal and nonfatal injury rates that prevail in Japanese coal mines with the conditions observed in the mines. Virtually all mines visited were attempting to prevent accidents and explosions, by apparently following known safety precautions for the prevention thereof. Some commendable safety innovations were observed at several mines; they indicated that mine officials are giving thought and consideration to hazardous conditions that affect their particular mines.Naturally, the operating officials and management were anxious to impress the writer with their interest in accident prevention and safety. Operating officials were found to be receptive to safety and wore interested in formulating definite safety programs. Some nines had well-planned and well-organized safety programs, which, if put into effect, would contribute greatly toward reduction of accidents.The approach to safety in Japan is quite different from that in the United States, especially the concept of personal responsibility for accidents and the extent to which the individual should be protected against hazards. Management is responsible for providing and maintaining safe working conditions. Collaboration between management and worker, as understood in the United States, does not exist in Japan.Increase in accidents since the cessation of hostilities is the result of unsettled economic conditions in the coal industry, influx of inexperience workers, and breakdown of discipline among the miners, who have been organized into unions. Those unions are greatly influenced by ""leftist"" tendencies.It was observed that the Japanese mine worker is fatalistic by nature and has little, if any, noticable safety consciousness. The most urgent major requirements to reduce accidents in the coal mines are to train the worker in accident prevention and instruct him regarding the inherent hazards of his occupation.Revision of the mining laws would help to reduce accidents if the companies would comply with such laws and provide safer working places and if the workers would cooperate with management and observe and comply with such laws as are enacted for their protection."

Dec 1, 1949

By B. J. Moore

This publication contains analyses and related source data for 310 natural gas samples from wells and pipelines in 16 States. All of the samples were obtained and analyzed during calendar year 1978 as a part of Bureau of Mines investigations of the occurrences of helium in natural gases of countries with free market economies. This survey has been conducted in the United States by the Bureau of Mines since 1917. In late 1965, the survey was expanded to include foreign gasfields. The analyses published herein were made by mass spectrometer and a special helium analysis appara¬tus, which are described in Bureau of Mines Bulletins 4862/ and 576.3/ The results of the investigation of the occurrences of helium are published annually to make the information available as soon as possible to the gas industry and the public in general. Twenty previous publications have presented the results of 11,573 gas analyses made prior to 197R. The first three, Bulletins 486,4/ 576,5/ and 617,6/ contain analyses and related source data on 5,218 gas samples collected from 1917 through 1960. The other 17

Jan 1, 1979