Search Documents

By John L. Watson

The processes of magnetic separation and cyclone classification are common in the mineral processing industry, and frequently the two are found in consecutive stages in the beneficiation of a magnetic mineral ore. The application of a magnetic field across the cyclone, to combine the two stages in treating a magnetic mineral pulp, has been investigated with a view to possible practical applications in the mineral industry The results of this research reveal that magnetic particles can be manipulated within the cyclone body by the application of a magnetic field, and that magnetic grades may be significantly upgraded with recoveries in excess of 90%.

Jan 1, 1983

By Fred D. Wright

This paper describes research at the Bureau of Mines experimental oil-shale mine at Rifle, Colo., to improve blasting techniques and reduce breaking costs. Many of the conclusions are applicable to any mining operation. Experiments Were conducted on many phases of blasting. The effectiveness of various grades of explosives was compared, and several different drill-hole patterns were tried in heading rounds. An experiment was conducted to determine the maximum effective burden for various diameter blast holes. High-speed motion-picture studies were made of blasts, and the time for initial movement of rock after detonation of the explosive was measured. Experiments with millisecond-delay detonators in heading rounds proved that, when used properly, these detonators result in improved fragmentation, economical use of explosive, and compact, easily loaded muck piles.

Jan 1, 1953

"Ground control research in underground coal mines has been ongoing for over 50 years. One of the most problematic issues in underground coal mines is roof failures associated with weak shale. This paper will present a historical narrative on the research the National Institute for Occupational Safety and Health has conducted in relation to rock mechanics and shale. This paper begins by first discussing how shale is classified in relation to coal mining. Characterizing and planning for weak roof sequences is an important step in developing an engineering solution to prevent roof failures. Next, the failure mechanics associated with the weak characteristics of shale will be discussed. Understanding these failure mechanics also aids in applying the correct engineering solutions. The various solutions that have been implemented in the underground coal mining industry to control the different modes of failure will be summarized. Finally, a discussion on current and future research relating to rock mechanics and shale is presented. The overall goal of the paper is to share the collective ground control experience of controlling roof structures dominated by shale rock in underground coal mining.INTRODUCTIONThe National Institute for Occupational Safety and Health’s (NIOSH) Office of Mine Safety and Health Research (OMSHR), formerly the United States Bureau of Mines, has been conducting research on ground control safety for over 50 years. The overall objective of the research is to reduce underground mining injuries and fatalities by characterizing roof conditions, improving roof support performance and application, and optimizing pillar design and mine layout. Underground mining has one of the highest fatal injury rates of any industry in the United States—more than five times the national average compared to other industries (CDC, 2012). Roof fall injuries can be severe, resulting in lacerations, bone fractures, amputations, and death. Non-injury roof falls can also be problematic, resulting in lost production, delays, blockage of primary escape routes, disruption to ventilation, and hazardous rehabilitation conditions.Coal mining is increasingly subject to more adverse geological conditions. Weak roof can be found in all coal mining regions in the United States, but there are a few geographically isolated areas with higher roof fall rates contributed to by particularly poor roof conditions, as represented in Figure 1. This figure shows that when non-injury roof fall rates are normalized to production, the Illinois Basin and Central/Northern Appalachia regions have the highest rates. These isolated regions have inherently weak roof even before mining has occurred, and this roof is easily damaged during the mining process. The weak roof in these regions consists primarily of shale. Shale can be troublesome in underground coal mining because it can appear massive but easily splits along bedding planes and is often moisture-sensitive."

Jan 1, 2015

By Sydney C. Mifflen

COAL MINING, with its some 15,000 employees, is directly responsible for the livelihood of one-fifth of the population of the Province of Nova Scotia and indirectly so for that of possibly another fifth. Deposits of coal are known and worked in four counties of the Province, from which is being produced yearly tonnages as noted below: Cumberland County 750,000 tons Piccou County 400,000 tons Inverness County 100,000 tons Cape Breton County 5,250,000 tons TOTAL FOR NOVA SCOTIA 6,500,000 tons Production in Cape Breton county is entirely from the one source, the Sydney coalfield, and not only is this field the most important in respect to output, as is disclosed above, but it is also the largest presently known deposit in the Province and holds the greatest tonnage yet in reserve for future mining. In the light of the above more or less generally known facts, it is trite to remark on the importance of the Sydney coalfield in the internal economy of the Province. On the other hand, not nearly as well-known nor as frankly recognized is its significance in the national life of Canada, for from this field is produced not only 80 per cent of the Nova Scotia coal but over 40 per cent of all coal mined in the Dominion. Another noteworthy comparison can be made from the fact that the Sydney field contributes 22 per cent of all the bituminous coal consumed in Canada, the remainder being made up of 7 per cent mined elsewhere in Nova Scotia, 27 per cent from other parts of Canada (British Columbia and Alberta, principally), while the remaining 44 per cent is imported, practically wholly, from the United States of America.

Jan 1, 1941

By E. P., Mathewson

THE most important improvements in copper metallurgy today are the advances in the art of leaching and electrical precipitation of copper from solution; the development of flotation processes; improvements in crushing and pulverizing machinery; the enlarged units of both reverberatory and .blast furnaces, together with the application of pulverized coal to both styles .of furnaces; the enlargement of' units for converting copper and the improving of the mechanical design of converter shells and equipment; the electrical precipitation of flue dust and fume from escaping gases.

Jan 1, 1921

By L. Yuan, J. Soles, D. Bahrami, W. Tang, R. Thomas

Mine equipment fires remain as one of the most concerning safety issues in the mining industry, and most equipment fires were caused by hot surface ignitions. Detailed experimental investigations were conducted at the NIOSH Pittsburgh Mining Research Division on hot surface ignition of liquid fuels under ventilation in a mining environment. Three types of metal surface materials (stainless steel, cast iron, carbon steel), three types of liquids (diesel fuel, hydraulic fluid, engine oil), four air ventilation speeds (0, 0.5, 1.5, 3 m/s) were used to study the hot surface ignition probability under these conditions. Visual observation and thermocouples attached on the metal surface were used to indicate the hot surface ignition from the measured temperatures. Results show that the type of metal has a noticeable effect on the hot surface ignition, while ventilation speed has a mixed influence on ignition. Different types of liquid fuels also show different ranges of ignition temperature. Results from this work can be used to help understand equipment mine fires and develop mitigation strategies.

Mar 2, 2022

By T. Prietl

Metallurgical vessel linings are multilayered, consisting of refractory bodies, insulation materials, joints, and additional space to control for thermal expansion. A unique biaxial hot testing press (BHTP) was installed at the RHI Refractories Technology Center Leoben, Austria to enable the three-dimensional behaviour of complex vessel lining segments to be investigated under simulated service conditions. Using the BHTP, the heat up and thermo-mechanical behaviour of magnesia chromite brick lining segments with and without mortar filled joints were examined. The results obtained during the initial heat up provided validation of CFD modelling of the lining system. In addition, after the heat up and under steady state conditions, the lining behaviour during deformation-controlled compression and relaxation was examined. These analyses generated important data regarding the stiffness, joint compressibility, and brick damage of the lining segments after cyclic loading and unloading as well as the benefits of using mortar joints in the lining. These investigations were performed in collaboration with the Christian Doppler Laboratory for Secondary Metallurgy of Nonferrous Metals, University of Leoben, Austria. The BHTP has been operational since November 2004 and is providing information regarding the thermo-mechanical behaviour of different lining segments.

Jan 1, 2007

By R. L. Amelunxen

P. T. Freeport Indonesia (PI) in conjunction with Crescent Technology Inc. has developed a method to predict the metallurgical performance of ores blends based on the behavior of their component ores. The question addressed in this paper is whether ores treated individually could be extrapolated to predict the behavior of a blend of ores. The work further investigates the use of modal analysis to establish individual mineral flotation kinetics in each of the ore zones. This information would lead to the prediction of grade-recovery curves of ores made up of those minerals. Nine samples of ore, representing various zones of FI's Grasberg ore deposit were tested metallurgically and examined microscopically. The same testwork was performed on blends depicting the 1994 mill quarterly feed. Flotation kinetics of the individual ores were then "mathematically" blended and compared to the results obtained from the quarterlies. The calculated kinetics of the actual blends of ore received by the mill were fed to the simulation program and compared to the actual mill performance.

Jan 1, 1995

By William C. McLaughlin

In the deep vein mines of the Coeur d'Alene mining district, rock bursts are a potential hazard to the mine structure and underground personnel. Damage repair costs are estimated by one company to exceed $1 per ton of ore mined. The Bureau of Mines, in cooperation with the mining companies, has conducted research intermittently over the past 10 years to help reduce bursts. Onsite inspections of major rock bursts were conducted, and reports were submitted to mine management; these included the geology and geometry of the affected area. The paper discusses the development and improvement of microseismic and surface monitoring equipment. The underground microseismic network, when operated on a regular basis and the results plotted daily, is capable of detecting stress concentration in certain areas. The surface seismographs record rock bursts, blasts, earthquakes, etc., throughout the district and show approximate location, time, and relative intensity of the event.

Jan 1, 1976

By Rodolfo Zanella

Au/TiO2 catalysts prepared by deposition-precipitation with NaOH (DPN) (~3 wt%) and urea (DPU) (~8 wt%) were tested in crotonaldehyde hydrogenation at atmospheric pressure. There is no differences in activity (mole.gAu -1 s-1) and selectivity between both DPU and DPN samples for a given activation treatment. This is due to the fact that DPU and DPN samples exhibit similar gold particle size distribution, although the gold loading in DPU is much higher that in DPN. The DPU samples were reduced under H2 at different temperatures (120-500 °C) or under air at 300 °C with various flow rates, to vary the average particle size within a large range, 1.7 to 8.7 nm. The selectivity to crotyl alcohol (selective hydrogenation of the carbonyl bond) is high, 60-70 %, and almost constant as a function of the particle size. The selectivity to crotyl alcohol is also constant for conversions between 10 and 50%. These results suggest that the adsorption mode of crotonaldehyde is of ?3 or ?4-type. In contrast, the TOF depends on the gold particle size, it drastically increases when the gold particle size is ~2 nm. Our results are in agreement with former studies that suggest that the gold atoms involved in the hydrogenation process are those of low coordination.

Oct 1, 2003

By Tianzu Yang, Weifeng Liu, Lin Chen, Wei Chen, DUCHAO ZHANG, HUI XIAO

Oxygen-rich side blow bath smelting (OSBS) technology was developed in 2000 based on Vanyukov process. This technology exceeds the traditional pyrometallurgical methods by its great processing capability, high metal recovery and environmental-friendly property. In the past 15 years, OSBS technology extended its application area from lead industry to bismuth, antimony and waste recycling industries, etc. This paper introduces the history and new developments of OSBS technology. The typical industrial applications examples of the OSBS technology in China, including high lead slag reduction, low grade bismuth-lead concentrate smelting and metallurgical waste recycling, are reviewed. Especially, the unique furnace properties and technical parameters are compared. Finally, the potential research directions of OSBS technology are summarized.

Jan 1, 2016

By G. C. Lipsyy

ALL mineral production? of Can11.da is transported in a mine car at some stage during its extraction. There are as many types and varieties of mine cars as there are of mines. Many of the cars in use were developed in the blacksmith shop. Others were designed by engineers and improved by the mine foremen and the mechanics. Every mine car has the ideas of miner, blacksmith, mechanic, and engineer incorporated in it. Many of these ideas are not generally known. This paper was written to make at least some of this information available to the mining industry. In drawings, tables, and notes, it gives all the important details pertaining to the cars. It .does not recommend any particular type of car for any particular piece of work, nor does it present drawings from which a car can be built. It gives the engineer or master mechanic information on many cars which he can apply to his own particular problems. It is hoped that this information will be of use to mine operators. If a few new ideas are conceived as a result of the paper, the author will feel that the effort of compiling it has been worth while. In order to obtain the data for the preparation of the paper, a questionnaire, copy of which is here reproduced, was sent to all the operating mining companies in Canada. An accompanying letter briefly explained the purpose of the paper and asked for co-operation in furnishing as complete information as possible.

Jan 1, 1945

By R. A. Ford

The paper outlines: methods used for the determination of wear metals in motor and transmission oils; contaminents in motor, transmission and crusher lubricating oils; and viscosity determinations. Case histories and costs are presented to illustrate the value of an oil analysis program. Introduction NORANDA MINES LIMITED (BELL COPPER DIVISION) is located on the shores of Babine Lake, approximately 450 miles north of Vancouver, British Columbia. Access to the mine is by road from Topley, B.C., about 40 miles away. When a preventive maintenance analysis program was first considered, it was obvious that if samples were to be sent out for analysis, results would not be available for at least a week, due to the distance from any commercial laboratory. The assay laboratory was asked to investigate the possibility of determining wear metals on site. A limited program was started soon after production commenced, and this has now grown to include all large mobile equipment as well as crushers and grinding mills. The laboratory also now determines viscosity, fuel dilution, dirt and abrasives, glycol and water. All these results are ready within two days. This paper will outline the methods used, data interpretation, several case histories and the benefits from such a program.

Jan 1, 1977

By R. C. Moe

Pelletizing studies were conducted to find ways of improving the metallurgical properties of acid and fluxed pellets. In acid pellets, melting temperature was controlled by the formation of low melting temperature fayalite during reduction. Formation of a permeable metallic shell during reduction allows diffusion of reducing gas to the pellet core, decreasing fayalite formation. With fluxed pellets, slag chemistry had the main influence on metallurgical properties. Mineralogical, chemical and structural transformations that occur during reduction were studied at various intervals for a number of Mesabi Range pellet types. Six pellet types were selected for further investigation based on significant differences in softening/melting characteristics. Retention of porosity in the metallic shell was found to be the overriding factor in determining softening/melting behavior.

Jan 1, 1990

By James L. Elder, J. P. Capp, James J. Dowd

The Bureau of Mines and the Alabama Power Co., jointly, conducted the first experiment undertaken in the United States in underground gasification of coal in place, at Gorgas, Ala. Milton H. Fies, manager of coal operations, Alabama Power Co., proposed the cooperative investigation to Arno C. Fieldner, chief, Fuels and Explosives Branch, Bureau of Mines; and assisted in supervising the experiment. The objectives of the experiment were to determine whether coal in place could be burned successfully and whether the burning could be controlled; the effect of the fire on the coal bed and the overlying strata; and the yield and quality of gas that could be obtained.

Aug 1, 1947

By R. Bissonette, C. Sunderman, R. Jacksha

The ability of wireless systems—e.g., voice communication, proximity detection, tele-remote operation, telemetry, etc.—to function satisfactorily (coexist) in the presence of other wireless systems is critical to the safety and health of mine workers. The failure of wireless systems to coexist could result in the delay, corruption, or outright loss, of critical data, voice, or video information. However, no mining-sector-specific regulations, standards, or guidelines exist to ensure the safe coexistence of wireless systems. This paper introduces the concept of wireless coexistence, implications in the mining industry, and the National Institute for Occupational Safety and Health’s (NIOSH’s) research approach to develop guidelines and recommendations to ensure safe wireless coexistence.

Feb 1, 2023

By T Muzondo, C Prins, D De Vaux, R Schouwstra

The Mogalakwena Platinum Mine in the northern limb of the Bushveld Complex is Anglo American PlatinumÆs only open cast operation exploiting the Platreef. The Platreef, which extends along the basal contact of the Bushveld Complex, is geologically and mineralogically a much more complex orebody than the Merensky and UG-2 reefs. Changes in the footwall and the genesis of the Platreef translate into a number of rock types being present. These rock types vary in hardness and recovery potential and present challenges to metallurgical staff trying to optimise the concentrator. A true understanding of the implications of treating these rock types is required if the maximum value from this orebody is to be obtained.In order to more accurately forecast production and incorporate ore variation in the mine plan and comminution and flotation circuits, a geometallurgical approach to managing the operation has been used and is being further developed.CITATION:Schouwstra, R, De Vaux, D, Muzondo, T and Prins, C, 2013. A geometallurgical approach at Anglo American PlatinumÆs Mogalakwena Operation, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 85-92 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

By D. G. Kesterke

The electrolytic reduction of uranium dioxide to molten uranium in fluoride baths at approximately 1,200° C was demonstrated. Electrolyte constituents were BaF2, UF4, and either MgF2 or LiF. Preliminary laboratory-scale experiments were made in which the uranium oxide was added continuously for 3 to 5 hours to the cell during electrolysis. Over 1,000 grams of metal of 99-8 percent purity was made in some tests, Major impurities were aluminum, barium, iron, silicon, carbon, and oxygen. The effects of cell design, geometry, and bath composition were investigated. Electrode arrangement was the most important factor in cell performance.

Jan 1, 1963

By Michael Tenenbaum

A REVIEW of process metallurgy of iron and steel during 1944 in many ways reflects the political and military developments of the year. Early in 1944 the tremendous wartime emergency expansion program was virtually completed and the industry directed its efforts to maintaining maximum production wherever needed. The vigorous production programs inaugurated to support the Normandy invasions did not persist as Allied armies approached Germany. General public apathy which developed with the prospect of an early ending of the European fighting was reflected in a general relaxation in armament programs. Toward the end of the year, as the prospect of a prolonged war became real, the entire program revived considerably and the need for steel became acute. Between January 1940 and October 1944 more than 12,400,000 tons had been added to the nation's steelmaking capacities, and over 12,700,000 tons added to the blast-furnace facilities. The total cost of this enormous program was more than two billion dollars. By July 1, 1944, total steelmaking capacity had exceeded 94,000,000 tons, with blast-furnace capacity rated at 68,400,000. Annual steel production, which was 88,900,000 tons in 1943, increased slightly during the past year and was estimated at 89,500,000. Production of pig iron also increased somewhat from 61,800,000 tons in 1943 to an estimated output of 62,500,000 in 1944. This review deals with a few of the numerous factors involved in maintaining the wartime iron and steel program at the level necessary to accomplish this enormous output.

Jan 1, 1945

By F. R. Cattoir

This Bureau of Mines study investigated molten salt electrorefining for beneficiating low-grade, high-carbon ferrochromium products which can be readily produced from domestic chromite concentrates. A second objective was to refine commercial ferrochromium into low-iron chromium products. Electrorefining of both types of ferrochromium in molten CaC12-NaCl-CrC12, CaCl2-MgC12-CrCl2, or KC1-LiCl-CrCl2 electrolytes produced chromium-iron products with virtual elimination of other impurity elements and some lowering of the iron content, Over 90 percent of the chromium present in the feed materials was recovered. The electrodeposited products were upgraded further by magnetic separation techniques into chromium containing less than 5 percent iron. The technical feasibility of preparing a premium chromium product from a low-grade, high-carbon ferrochromium made from domestic chromite was demonstrated. Chromium virtually free of carbon, oxygen, and silicon from high-carbon ferrochromiums was produced. In addition, the amenability of three commercial grades of ferrochromium to electrorefining and magnetic separation for preparing chromium metal containing less than 5 percent iron was determined.

Jan 1, 1969