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By B. Valentim

Policies for reducing NOx emissions have led power plants to restrict O2, resulting in high-carbon fly ash production. Therefore, some potentially useful fly ash, such as the economizer fly ash, is discarded without a thorough knowledge of its composition. In order to characterize this type of fly ash, samples were collected from the economizer of a Portuguese power plant burning two low-sulfur bituminous coals. Characterization was also performed on economizer fly ash subsamples after wet sieving, density and magnetic separation. Analysis included atomic absorption spectroscopy, loss-on-ignition, scanning electron microscopy/energy-dispersive X-ray spectroscopy, optical microscopy, and micro-Raman spectroscopy. Key words: Fly ash; Petrology; Petrography; Economizer fly ash

Jan 1, 2009

By Northcutt Ely

This volume summarizes mining and petroleum legislation in 45 African jurisdictions. Within these jurisdictions, primary attention is given to requirements that must be met in each country for acquisition of rights to permit development of mineral resources. Coverage includes: First, identification of the controlling laws or statutes governing minerals acquisition and reference to the administrative authority; second, analysis of the laws governing mines and quarries and their products; third, analysis of laws applicable to natural gas, petroleum, and related materials; and fourth, mention of laws regulating offshore operations. Where pertinent, sections dealing with historical background or administration have been added. In countries where minerals are subject to control of states or provinces, those areas are considered separately from the central government.

Jan 1, 1974

By R. W. Lewis

Spectrochemical procedures were developed using dc arc excitation for the determination, in parts per million, of 18 impurity elements in electrorefined beryllium and high-purity beryllium oxide. The metal samples were dissolved in dilute hydrochloric acid, evaporated to dryness, and converted to the oxide in a muffle furnace at 900° C. Germanium oxide was added as an internal standard for the determination of 15 of the elements, copper oxide for boron and molybdenum, and neodymium oxide for calcium. The average coefficient of variation was 11 percent with the exception of copper, which averaged about 43 percent.

Jan 1, 1962

By Lawrence G. Houk

In modern warfare mica is truly indispensable. The coordination of combatant units necessitates maintenance of intricate communications equipment, in the construction of which high-grade sheet mica is essential. Scrap, ground, and the poorer qualities of block mica, which are less essential to the military program, are not considered in this paper. Furthermore, as the paper is designed primarily to assist mica miners, mica derivatives such as splittings and films are also excluded from discussion. The paper therefore relates solely to block mica of strategic quality.

Jan 1, 1942

By George A. Page, Hewitt Wilson, Vance S. Cartwright

"Purpose of InvestigationThe process of removing solid material from liquid suspensions has been studied at the Northwest Experiment Station, United States Bureau of Mines, in cooperation with the University of Washington, as part of a general program to investigate the dewatering of Pacific Northwest plastic kaolins, which is difficult by ordinary filter-pressing methods. The present paper is a progress report of the work began by Vance S. Cartwright in 1928 and continued in 1931 and 1932. Spray evaporation is believed to be valuable for the following classes or grades of clay and clay mixtures:(1) Highly colloidal, plastic-type clays, which release their mechanically attached water with difficulty; (2) clays prepared for shipment in pulverized or powdered condition; and (3) synthetic, ceramic, porcelain, and tile mixtures prepared as aqueons suspension, dried and pulverized before molding. Dilute suspensions can be dewatered by spray evaporation to produce concen-trated casting slip or plastic clay with a lower water content.The most common dewatering method used in preparing powdered kaolin for the market comprises the following steps: Reduction of the water content by filter-pressing from approximately 75 percent in the thick ""slip"" condition to about 30 percent in the condition; further reduction of the water in the filter-press cakes by heat to about 5 percent; and pulverization of the dried cakes in hammer or dust. These three steps can be simplified to a single process by spray evaporation."

Jan 1, 1935

By H. Brindel

The paper point out the importance of a maintenance program at Toquepala, as to the effect that any changes in the above may have on the program and organization. The Southern Peru Copper Corporation carry out a training program in operation with a appropiate peruvian staff, as it has been established the basics for a sound, preventative maintenance and repair organization. In consecuence, this company decided to expand a two -fold program of training and maintenance so that the Peruvian personnel will not only be an aid to the Company but a national as set to Perú as well.

Aug 20, 1963

By A G. Noble

Tunnelling for hydro-electric power projects can be a very challenging component of the overall development. In contrast to urban transportation tunnelling where the logistics for access and supply of power, water and other essentials are readily available, hydropower projects are usually in very remote locations and all necessary plant, equipment, spares and materials need to be brought in and the site must function as a self sufficient unit.For a large scheme the river diversion tunnel(s) are usually on the initial phase critical path in order to meet the non-negotiable deadline of river diversion before the onset of the wet season. A newly formed tunnelling crew, once mobilised to the site for the project, will face the first major learning curve of the project’s systems and logistics during this critical tunnelling activity.Power tunnels convey the water to the turbines in the powerhouse and are usually on the critical path for the main works, especially if the scheme comprises a powerhouse located within an underground cavern. A modern cavern arrangement requires a complex warren of various openings: access adits, ventilation/cable tunnels, shafts, surge tunnels, etc.Hydropower tunnel construction tends to be dominated by tunnel boring machine (TBMs) or drill-and-blast excavation techniques and each has its challenges in very remote locations. TBMs still have long lead times as for any type of project, but additionally require a thorough roads and bridges infrastructure assessment of the country from the port of entry to the site to ensure a problem-free delivery. In some cases the project also requires the establishment of a complete precast concrete segment production facility and the space for creation of laydown areas; there is no ‘just-in-time’ delivery mechanism applicable to typical remote hydropower sites.This paper highlights the technical and risk management considerations in the planning, design and construction of tunnels for hydropower projects. It contrasts the typical factors that govern the design of urban transportation tunnels with those for remote hydropower tunnels. The perspectives of stakeholders are provided including those of international lenders. With examples from large and small scale projects across the globe it provides an insight to all parties and in particular, those tunnellers that are working in the hydropower field for the first time.

Mar 8, 2011

By Miguel Reyes, Chenming Zhou, MATTHEW GIRMAN

Electromagnetic energy emitted from electronic devices has been known to interfere with other electronic systems, hindering their ability to function properly. Mines have many electronic devices critical to the health and safety of mine workers that could be negatively affected by electromagnetic interference (EMI). To ensure that devices are electromagnetically compatible, tests must first be conducted to measure emissions and check for immunity. There are many standards available across multiple industries that prescribe emission limits and test methods for electronic devices. Due to the unique environment of an underground mine, it may not be enough to simply adopt a standard from another industry to mining. A literature review has been conducted, and an overview of EMI standards in other industries will be provided in this paper. Also, an example of how a standard can be applied to mining equipment is presented. Finally, recommendations on standards which could potentially be applied to mining will also be included. This work will inform the mining industry of EMI standards in other industries so that mine workers and technology manufacturers have guidance of the steps that can be taken to investigate and reduce the impact of electromagnetic interference and potentially work toward electromagnetic compatibility. The findings and research involved in this effort can also be used to explore the need to develop mining-specific EMI recommendations and standards.

Nov 25, 2021

By James Gayley

(Wilkes-Barre Meeting, June, 1911.) THE paper presented to the Institute in 1910, by H. 0. Hofman, on Recent Progress in Blast Roasting,1 has called the attention of the iron industry to the adaptability of these processes to the reclamation of by-products such as flue-dust and blue billy, and the better preparation of concentrates and fine ores for use in blast-furnaces. The waste of valuable iron-ore through the production of flue-dust has increased at an enormous rate, and much of it has in reality been wasted as far as future recovery is concerned. Only in recent years has a possible future value been recognized, and the material stored. The increased use of Mesabi ores, which carry considerable fine ore, is principally responsible for the great increase in the production of flue-dust. The amount of fine material that is carried over depends on the fineness of the material and the velocity of the gases, and also to a very great extent on the regularity or irregularity of the working of the furnace. Attempts to recover a part of this loss have been made by recharging a portion of the production into the furnace, but as this material has been once carried out from the furnace, it is naturally in good shape to be carried out again. A recent practice at some works, is to soak the flue-dust thoroughly with water to give it more cohesiveness, but by many this is considered of doubtful advantage in the furnace, and the gases are in consequence heavily laden with moisture. There are vast deposits of magnetic iron-ores in the United States and Canada that are too low in iron for use at the present time, but which can be economically concentrated into very rich material ; in many cases the fineness of crushing necessary to secure proper concentration has prevented their

Aug 1, 1911

Research workers From the Bureau of Mines and industry met with other government and industry representatives in Pittsburgh, Pa., on January 22, 1975, to discuss the results of research under the Bureau of Mines Noise Control Program. The program, aimed at reducing noise in mines, is functionally divided into three major areas: Instrumentation, personal protection, and noise abatement. This proceedings contains the opening remarks to the seminar and seven technical presentations based on various aspects of noise abatement and control.

Jan 1, 1975

By T L. Horsley

The change from a seasonal to a continuous mining operation at Cassiar has been accompanied by increased emphasis on the preventive maintenance of mining equipment. This paper describes how equipment maintenance is organized, and details some maintenance practices that have proved advantageous to the Cassier operation. Introduction Cassiar Asbestos Corporation Limited is currenly carrying out an open-pit mining operation at the 6,300-foot elevation on McDame mountain in northern B. C. A 6-mile road connects the mine to the mill and plantsite at the 3,500-foot elevation. Ore concentrate is delivered to the mill via a 3llz-mile tramline. Naturally level ground does not exist in the mine area. The weather is typical of mountainous regions, exhibiting wide and rapid variations in temperature. It is generally wet and windy at the mine elevation, and a heavy snowfall is common. The rock types vary from a soft, sheared serpentine to massive serpentine, to medium-hard, friable sediments to hard, blocky volcanic flows.

Jan 1, 1964

By K. E. Soroka

More than 500 fires are now burning in abandoned coal waste banks and coal deposits in the United States. Once established, such fires can burn for decades, and extinguishing them by conventional methods such as surface sealing to exclude air, excavation to remove fuel, or flushing to cool the fire zone is usually difficult and always expensive. Burnout Control, a technique developed by the Bureau of Mines for the control of abandoned coal fires, involves the accelerated combustion of coal in place with total management of the heat and fumes produced. A burning waste bank or mine is placed under negative pressure relative to the atmosphere, and heat and combustion products are drawn from the combustion zone through an exhaust ventilation system. Heat produced appears as sensible heat in the exhaust, at temperatures as high as 1,0000 C (1,832° F), and could be recovered for the production of steam, hot water, process heat, or electricity. The Bureau's first held field demonstration of Burnout Control was at Calamity Hollow in Allegheny County, PA (near Pittsburgh). Calamity Hollow was the site of an underground mine in the 1900's and was surface mined in the 1940's. In the winter of 1961-62, a fire of undetermined origin was discovered in the exposed coal. In 1963, the Bureau constructed a trench barrier around the fire and a surface seal over the affected area. The fire was isolated but not completely extinguished. In 1979, when the Bureau began work on the Calamity Hollow Mine Fire Project to demonstrate controlled burnout, the fire was still smoldering on the hot side of the trench barrier. The project, which was begun in December 1979 and ended in July 1982, consisted of the design, construction, operation, and subsequent dismantling of a Burnout Control ventilation system. This report is the fifth in a five-part series that describes the Calamity Hollow Mine Fire Project. The first report, part 1, describes the design and construction of the field installation. Part 2 will present the results of a continuous 4-month burnout operation. (Because part 2 involves the analysis of a substantial body of data, it will not be published until after publication of parts 1, 3, 4, and 5.) Part 3 describes the instrumentation used to control and monitor the progress of the burnout operation. Parts 4 and 5 deal with the closeout phase of the field demonstration. Part 4 describes the procedure used to quench the fire, and this part (part 5) describes the final excavation and backfilling of the heated zones. The reports in this series document the Calamity Hollow controlled burnout demonstration which showed that (1) controlled in situ combustion is a feasible method for controlling underground fires in abandoned mines, (2) the resultant thermal exhaust output is sufficient for energy utilization, and (3) water injection-fume exhaustion is a potentially effective method for cooling large underground fire zones. Further investigations of both Burnout Control and the water-injection-fume exhaustion quenching procedure are planned.

Jan 1, 1986

By Oliver Bowles

The conservation of fuel became a critical problem during the recent war, particularly in the East. Fuel-oil supplies were short, the demands for coal increased, and householders were called upon to reduce the temper- atures in their homes. Home owners were urged to employ every means avail- able to reduce fuel consumption, the most important of which was to insulate their dwellings. The Bureau of Mines, United States Department of the In- terior, took steps to promote the conservation of fuel by issuing a report3/ on home insulation which has been widely circulated. The American populace responded patriotically to the requests of various Government agencies for voluntary conservation of fuels; they accepted cheerfully the restrictions imposed, the crisis was weathered, and with termination of hostilities the unhappy situation was relieved. Fuel conservation, however, is not merely a war emergency problem; it is a continuous, ever present issue. Coal and petroleum resources are ir- replaceable assets, and when fuel is burned it is exhausted - there is no scrap recovery. Fortunately, the United States has been richly endowed with mineral fuels; but population is growing, industrial demands for fuel are increasing, and mines and oil wells are becoming deeper and more costly to operate. For the sake of generations to come all national resources, particularly irreplaceable fuels, should be conserved. A long step in the direction of fuel conservation is the general rec- ognition that insulation is an essential element of dwelling construction. Fortunately, when the home owner takes measures to conserve fuel, he is not called upon to make purely unselfish (altruistic) sacrifices to advance the general welfare; he has the added incentives of saving money and promoting more comfortable living in his own home.

Oct 1, 1946

By N. O. Lotter

The reliability of a set of flotation results is key to minimizing project risk, either at the commissioning of a concentrator or at the point of implementing an improvement to an existing concentrator operation. High-confidence flotation testing (HCFT) was developed for this purpose and is part of the list of technologies at various scales used by Xstrata Process Support (XPS) in addressing these projects. The methodology is based on two principles: one, to ensure that the ore sample is representative and has been well-blended and subsampled; two, to perform the flotation tests in sufficient numbers of replicates with appropriate quality controls, so as to improve the reproducibility of the test data. Across ten years of research on this methodology at Xstrata Process Support, Sudbury, several improvements to the HCFT method and complementary connections between sampling and quantitative mineralogy have been developed. Two case studies are reviewed. These show the capability of this system in both optimizing an existing concentrator operation and in serving a new mine scenario. Further work to improve the efficiency of this procedure has been identified. Key words: Flotation testing, Flotation

Jan 1, 2010

By V. Jiricny

There is a growing need to process galvanized steel scrap from automobiles, etc., in order to remove the zinc coating that otherwise causes problems in remelting of the scrap in electric arc furnaces. One approach that has moved to the pilot plant stage is that of Metal Recovery Technologies, Inc., of East Chicago (MRI). That company leaches the zinc fiom the scrap with a sodium hydroxide solution. The leached and washed scrap can then be returned to the steel industry. What is left is a sodium hydroxidelzincate solution which must be processed to recover the zinc and the NaOH. Presently, this is done by MRI using electrodeposition on planar electrodes at moderate current density and the resulting zinc is in the form of fine powder which is hard to process into, say, zinc for galvanizing. MRI has supported an investigation of a novel electrode, the spouted bed electrode (SBE), for zinc electrodeposition. In laboratory cells, zinc particles with low porosity have been grown up to 3mm in size. Microanalysis of the deposited zinc showed low level of impurities. DC energy consumption values were usually in the range of 2-2.5 kWg which is well below the energy consumption of the existing cells (and of present-day cells for electrowinning from acid sulfate electrolytes). These results were achieved at current densities (few thousand A/m2) that are much higher than possible with conventional electrodes. Discussion is provided of the scale-up of the cell to a commercial scale.

Jan 1, 1998

By G. J. Hartman

The Fort Cady in situ borate mining project involves recovery of boron from a mineral deposit located over 1400 feet below the surface. The resource recovery method is being developed using in situ mining technology employing weak acid solution injected directly into the ore body. As the acid contacts the calcium based ore (primarily natural colemanite), the contained borate values are digested as boric acid. This boric acid solution is then pumped to the surface by use of submersible pumps. At the surface the borate values are recovered as a finely divided solid white powder after a series of chemical reactions and precipitations resulting in the production of calcium borate. The refined product is then sold under the trade name CADYCAL 100.TM All environmental permits for up to a production rate of 90,000 tons per year have now been obtained. These permits required an Environmental Impact Study (EIS) for federal lands and an Environmental Impact Report (EIR) for the private portion of the property. Regulatory permitting took over 5 years to obtain all authorizations for this operation. The ore body has an average thickness of 118 feet extending over 273 acres. At a production rate of 90,000 tons per year with only a 70 percent resource recovery allowance, in place reserves are sufficient to sustain production for over one hundred years.

Jan 1, 1997

By C. H. Wyndham, N. B. Strydom

INTRODUCTION Acclimatization of the labour force to heat is an integral aspect of gold mining in South Africa. A recent survey revealed that about 250,000 Bantu mine workers require to be acclimatized to heat each year. Until 1965 men were acclimatized by means of one of the Chamber of Mines methods (introduced by the Human Sciences Laboratory in 1953). This type of acclimatization was carried out underground where men shovelled rock in hot stopes under careful supervision. However, it has become increasingly difficult in the last few years for mines to provide underground the conditions of work and environmental heat required for adequate acclimatization to heat. In examining an alternative to acclimatization in underground hot stopes, the Human Sciences Laboratory carried out a trial in 1965 of acclimatization in an air-conditioned climatic room on the surface of a mine. The new procedures developed from this trial have been so successful that there are today 26 climatic rooms on different mines. These rooms have been built following a design proposed by Mr Hodgson of the National Mechanical Engineering Research Institute1. Approximately 85 per cent of the total number of men being acclimatized each year are put through the new procedures in these climatic rooms. This paper gives an account of the problems which arose and how they were solved, the inter-relationship between physical conditioning and climatic room acclimatization, the prodecures developed for elimination of labourers with low maximum oxygen intakes, and the advantages of climatic room acclimatization. CLIMATIC ROOMS The majority of the climatic rooms (twenty) have been built on the surface, but a number (six) of mines preferred to establish their acclimatization centres underground in order to decrease the initial costs involved in the construction of such facilities. These underground climatic rooms are usually located near shaft stations in redundant haulages and they can accommodate from 200 to 400 labourers, thus eliminating the need for multiple acclimatization shifts. Figs. 1-4 illustrate various aspects of a surface climatic room. PROBLEMS WHICH AROSE IN INTRODUCING CLIMATIC ROOM ACCLIMATISATION There were four main problems which arose in connection with the introduction of the new method. These were: (i) The type and rate of work to be used. (ii) The air conditions required to obtain optimum acclimatization. (iii) The duration of exposure to heat each day and the total number of days of acclimatization. (iv) The methods of cooling labourers with high body temperatures. Shovelling rock would have been the desirable type of physical work to employ, but the air-conditioned space required to accommodate large numbers of men and the difficulty in standardizing the work rate in shovelling led to the decision to employ instead the work procedure used by the Human Sciences Laboratory in acclimatizing men in the Laboratory. This is the lifting of the body weight against gravity when men step on and off a bench. It has the advantage that large numbers of men can work physically at the required rate in a relatively small space (120 men can be accommodated in an area of 70 ft by 21 ft) and the cost of construction and ventilation of the climatic rooms is thereby reduced. Also the work rate can be standardized by varying the height of the stepping benches in relation to the individuals' body weights. The next problem was the air condition to be used in the climatic rooms. The Laboratory's research experience in acclimatization led it to choose an air temperature of 89°F (with the air almost saturated with water vapour) and an average velocity of air movement of 100 fpm. This air condition was combined with a work rate of 1,560 ft lb/min (oxygen consumption 1.0 litre/min) on day 1, and the work rate was increased gradually over the period of acclimatization to reach a work rate of 3,120 ft lb/min (oxygen consumption 1.6 litres/min) on day 9.

By John G. Groppo, James C. Hower, Cortland F. Eble, Rick Q. Honaker, Alireza Valian, Stephen F. Greb

Coal and coal combustion byproducts are potential candidates for alternative resources of REEs (rare earth elements). The Illinois Basin is a major coal-producing district in the USA, but little work is available on speciation of REEs in the basin’s coals. In this study, a total number of 382 samples from known locations in the Illinois Basin coal beds were acquired, analyzed for their REE contents, and investigated for any spatial trends or chemical correlations. This study includes Springfield, Herrin, and Baker coal beds—the most heavily mined coals in the basin. An average coal ash from the basin contains 320 ppm REE, with Baker being the highest (407 ppm on average). However, the distribution of REEs in the coal beds was laterally and vertically heterogeneous. A number of trends were found in the REE variations. The most important trend was the relationships of the REE concentrations and fractionations with the distance from the syndepositional sandstones. The total REE concentrations were higher in the proximity of the sandstones, likely due to the increased deposition of detrital material. This increase was the most significant in Springfield coal (90%) and least in Baker (6%). Those coal samples from the Springfield and Herrin coal beds distal from the syndepositional sandstones had a heavy to light REE ratio (H/L ratio) of 0.40 on average, whereas in proximal locations, the ratio was dropped to an average of 0.30. This trend was not significant in the Baker coal bed. In general, higher mineral matter in the coals was associated with higher REEs. In coal preparation plants, refuse rocks can have up to 360 ppmREE. However, the ashes of the cleanest coals had higher REE levels. Such ashes also have a higher ratio of heavy to light REEs. The highest REE concentrations were found in the claystones and the shales associated with the coal beds. Since the naturally occurring calcite, quartz, and pyrite samples were depleted in REEs, an association of REEs with the clay minerals can be suggested.

Jul 20, 2020

By John P. Savage

This paper is one of a series being prepared by the United States Bureau of Mines on tunneling methods. The tunneling methods described are those used at the Ojuela unit of the Compania Minera de Penoles, S. A., the Mexican subsidiary of the American Metal Co., Ltd., of New York. The Ojuela unit is situated some 4 miles southeast of Mapimi, Durango. Mexico, the latter place being connected by a 15-mile narrow-gage railway with the standard gage railroad at Bermejillo, some 40 miles to the north of Torreon, the location of one of the company's smelters.

Jan 1, 1931

By M. L. Whisman

The Bureau of Mines developed and tested in the laboratory several innovative techniques for reclaiming used lubricating oil. These processes included percolation through both chemically treated clay and ion-exchange resins, distillation through batch and continuous wiped-wall vacuum apparatus, treatment with solvent extraction systems, and chemical removal of impurities with chelating agents. In each treatment, the criteria of evaluation was oil recovery and reduction of acidic and metallic components. Both vacuum distillation and solvent treatment ranked high in their abilities to remove acidic and metallic components of the used oil with good oil recoveries. A combination of the two techniques gave the best overall results in terms of quality evaluations made by established bench tests. The methods were not ranked according to economic practicablity.

Jan 1, 1974