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By G. R. Tostengard

"The paper identifies functional areas which frequently can yield significant productivity improvement. Emphasis is placed on the repair and maintenance, material supply and training functions. Successful approaches are discussed in some detail, and typical results which have been achieved are reviewed.IntroductionA challenge which at all times confronts the manager o f any mineral operation is the potential to improve his operation no matter how effective it might be a t the present time. The challenge has been present through my entire lifetime and I suspect a good many years prior to that and, I expect, will continue many year s and decades in the future. The competitive and economic situation in which we in the minerals industry find ourselves today makes the challenge eve n more important during the 1980s. In many cases it’s a question of survival, not simply pr of it improvement.There are, of course, many avenues to improving profitability; technological changes, new equipment and facilities, improved products, improved mine plans, etc. All of these are important and must be addressed by each manager. This paper focusses on just one avenue to improvement and that is ""improved management"", not so much of management at the boardroom level but of improved management o f the facilities and workforce as the y currently exist. Management implies control. There are three areas where control is often found lacking:1, Repair and maintenance of equipment and facilities;2. Material supply including procurement, inventory control and warehousing; and3. Training.These three areas are all complex and difficult to manage and they are all but ignored in the formal education which our industry's manager s normally receive. They are areas which can be improved with relatively small investments and therefore, they represent especially attractive improvement targets during the 80s when, for most of us, investment dollars are very difficult to come by."

Jan 1, 1983

By George F. Crocker

Introduction The Helen mine and the Victoria mine of Algoma Ore Properties, Limited, in the Michipicoten district, Ontario, are 120 miles north of Sault Ste. Marie, on the north shore of lake Superior. They are on the Algoma Central railway between Hawk Junction and Michipicoten Harbour. Between them, these mines have produced 10,757,113 tons of iron ore. From 1900 to 1918, 2,823,369 gross tons of brown ore was shipped, and from 1939 to the end of 1949, 7,933,744 tons of siderite was produced from the open-pit operations and underground development. The finished product, known as 'Algoma sinter', is shipped to blast furnaces both in Canada and the United States. The iron-ore bodies are a part of a tabular shaped area of iron formation that extends over a length of more than 10,000 feet and has maximum width of 1,000 feet. The two siderite orebodies, known as the Helen and Victoria, are separated by two diabase dykes. The Helen orebody is 1,600 feet long with a maximum width of 250 feet and the Victoria is 1,200 feet long with a width comparable to the Helen. These orebodies are considered to be a replacement of the original rock by iron carbonate. The introduction of the iron-1bearing material probably occurred after the development of the major folded structures. The open-pit mining of siderite started in the Helen ore body in 1939 and continued until 1945. During this period, 3,853,395 tons of ore was mined. Open-pit mining started in the Victoria body in 1946 and is still being carried on. Underground development commenced in September, 1947. Diamond drilling and surface sampling had shown the Helen deposit to average 35.61 per cent Fe and 7.28 per cent SiO2, and the Vi.otoria deposit 33.73 per cent Fe and 10347 per cent SiO2?

Jan 1, 1950

By S. J. Page

The personal dust monitor (PDM) is a combined tapered element oscillating microbalance (TEOM) respirable dust monitor and cap lamp, configured to have dimensions and weight similar to those of a lead-acid miner’s cap lamp battery. The Higgins-Dewell (HD) cyclone design operated at 2.2 L min-1 airflow has previously been reported to have low bias relative to the International Organization for Standardization (ISO) convention. Previous reports have described the PDM as meeting the NIOSH Accuracy Criterion. In order to avoid certain analysis anomalies encountered during these evaluations, a different method of establishing the PDM relative standard deviation was employed. Re-analysis of laboratory data for both the early prototype and precommercial PDMs indicates that the PDM still meets the NIOSH accuracy criterion, and that the precommercial PDMs are more accurate than previously reported.

Jan 1, 2011

By Franklin H. Persse

To meet escalating energy requirements, substantial increases in production from the strippable coal and lignite deposits in eastern Montana, western North Dakota, and northeastern Wyoming already have occurred, and further expansions are expected at least until the year 2000. Such production, attributable largely to rising demand for low-sulfur coal, must be accomplished with a minimum of adverse effects on the environment. Information on geology, climate, and current land use in the Upper Missouri River basin is presented in the Bureau of Mines review as a guideline to what operators may expect during and after mining. Proven methods of protecting the air and water from pollution and of restoring mined land for other uses are described, and untried methods of land reclamation, some with equipment yet to be manufactured, are discussed as possible means of maintaining aesthetic values in the basin. Costs incurred to protect the environment are part of the production cost and thus are borne by the ultimate consumer. Unit production costs are less for the thick coal and lignite deposits of the basin than for the thinner but higher Btu coal deposits of the Eastern and Midwestern United States. Precise comparisons of environmental protection costs between mines in such disparate areas cannot be made, because of differences in physical conditions, accounting procedures, and other variables.

Jan 1, 1975

By Franziska Günther, Helmut Mischo

The calculation of costs for an underground mine, as well as the planning of the equipment and materials to be used, is a complex and time-consuming process. The estimation depends on a multitude of parameters, and all mining processes are interconnected. A novel tool has been developed that enables automated calculation of underground mines and allows for the comparison of the effects of changing individual parameters. Previously, changing individual planning parameters often necessitated a complete recalculation of the mine. The newly developed calculation tool provides an innovative planning aid that allows for more efficient and accurate mine planning and cost estimation. The tool enables the user to implement continuously up-to-data costs and prices. This allows for more accurate planning data and results. The underlying concept of the calculation tool, its implementation at a planned quartz porphyry mine in Germany, and the verification of the tool at an existing underground mine will be presented.

Feb 1, 2025

By Gyan S. Rajhans

"The strategy of fibrous dust sampling is discussed, various sampiing methods are critically reviewed .and their application to coal dust is demonstrated. Fibre counting is described in detail. An attempt is made to explain the basis of determining the threshold limit value of asbestos and other dusts. The paper also discusses such dust control methods as enclosure of the process, effective local exhaust ventilation, segregation, substitution, wet processing and continuous monitoring of the return air for recirculation."

Jan 1, 1970

By Hao Zhang, Mi Zhou, Lichun Jiang, Xihong Zhang

This study investigates the roof stability of underground limestone mining in the presence of stratified joints during the excavation process. An analytical solution is derived to predict the stresses and deformation of underground tunnel structures, with the structure simplified as a double-hinge arch. The accuracy of the analytical model is validated through comparison with finite element modeling results. A parametric study is then conducted to assess the influence of different design parameters on the optimization of tunnel stability during excavation. The results indicate that the best stability of the tunnel can be achieved in engineering practices when the applied load (q) is 5 MPa and the joint inclination angle (θ) is 45°, with the roof span and thickness set at either 12 m and 8 m or 15 m and 10 m. These findings provide valuable design guidance for underground limestone mines with stratified joints.

Oct 18, 2023

By BUREAU OF MINES

Mercury has been used by mankind since prehistoric times. It has been, and is now, widely used in industry and medicine and has unique properties which make direct substitution difficult or impossible. At present its prin- cipal uses are for electrical apparatus, control instruments, electrolytic soda preparation, mildew-proofing paints, pesticides, and medical and dental preparations. Deposits of mercury are less common than those of other base and precious metals, but some of the deposits are very large and have been ample to meet the world's past demands. The price of mercury has had many sharp fluctua- tions, but in general, the limited number of producers has resulted in a more stable price structure than that of many other commodities. The United States has been one of the main producers of mercury, and from 1850 to 1961 produced 3,247,704 flasks. Yearly production since World War II has varied from 4,535 to 38,067 flasks. An estimate of domestic resources of mercury producible at various price ranges was prepared for each mercury mine by combining specific knowledge of mercury mineralization with estimates of potential, based on geologic informa- tion and past production history. The sum of the individual estimates for each price range is shown in a table. A parallel estimate of nationwide production potential was made from a study of past price and production relationships. These were analyzed by plotting yearly production figures against the previous year's price, expressed in dollars of constant purchasing power. An equation was fitted to the data by mathematical means and was used to extend the curve into areas of higher than historic prices. Potential production rates at various price levels were taken from this graph. The estimated yearly production rates were used to make an estimate of total potential based on the premise that produc- tion rates and reserves have a proportionate relationship.

Jul 1, 1964

By Gianni Bartolacci, Patrice Nadeau, Szatvanyi. Gerard, Carl Duchesne, Claude Chrétien

"Combustion is used throughout the mineral processing industry to produce steam in boilers, to dry concentrates in rotary dryers, and to apply heat treatments in pyrometallurgical furnaces. Tight combustion control is very important in latter type of furnace since the combustion conditions directly affect final ore quality. However, achieving tight combustion control is not straightforward since most of the flames encountered in industry are turbulent non-premixed flames, they are affected by several unmeasured disturbances and are often produced by burning several types of fuel simultaneously, some of them coming from other parts of the plant. A novel method is proposed in this paper to improve process and product quality control as well as to optimize the combustion conditions based on digital flame color images. Multivariate Image Analysis and Regression is to used extract the flame color characteristics from images to predict the solids discharge temperature of an industrial rotary kiln. It is shown that this method yield extremely good 10 minutes ahead forecast of the temperature and should lead to a substantial reduction in product quality variability as well as in fuel consumption.INTRODUCTIONFuel-fired furnaces are often used in the mineral processing industry for various purposes, such as for the production of steam (utility boiler), in conjunction with rotary dryers to dry mineral concentrates or in pyrometallurgical processes for induration, roasting, and so forth. These furnaces are necessary in the supply chain from the mine to the metals, but their operating costs are constantly rising due to the fluctuations in fuel prices. Moreover, these processes are now targeted by the Kyoto Protocol since they are energy intensive and they produce significant amounts of CO2 and other pollutants such CO, NOx and SO2. To achieve both a reduction in operating costs (i.e. fuel consumption) and in pollutant emissions while maintaining or improving product quality, one needs to have a very good control of the combustion process."

Jan 1, 2005

6889. Aslakson, C. I., and Swick, C. H. Gravity Observations in Peru and Colombia. Coast and Geodetic Survey,-Special Pub. 233, U. S. Government Printing Office, Washington, D. C., 1943, 18 pp. (Price, 10 cents.) In accordance with the policy of cooperation among American republics, the-United States Coast and Geodetic Survey in 1941 made gravity surveys in Peru and-Colombia. The information was desirable for determining the figure of the earth for geophysical purposes and for studying the relationship between intensities of gravity and deflections of the vertical. The survey instrument was the Brown pendulum apparatus. 11 gravity stations were established in Peru and 13 in Colombia. The results obtained at these stations are given in a table covering observed gravity, theoretical gravity, and anamalies. - V. S.

Jan 1, 1943

By Mahamuda Abu, John Kalimenze, Benatus Norbert Mvile

The central Dodoma region of Tanzania is one of the regions defined by the Tanzania Craton (TC). Although the Craton gold mineralization has been well explored and hosts most of the gold deposits in the country, the understanding of the mineralization potential of the Dodoma region is still an enigma. This study using trace elements geochemistry of soil samples aims basically at providing information for future exploration works in the region by delineating the possible mineralized zones, the pathfinder elements, and the lithological facies to target. Generally, there is an anomalous spatial distribution of a probable Cu-Au deposit in the N, NE, S, and SE parts of the region and are prospective areas worth exploring for gold from the Gaussian variogram models. The multivariate statistics shows that Cu, Pb, Zn, and Fe are the main pathfinder elements while searching for Au mineralization in the region. The gold deposit is most probably a Cu-Au porphyry type, although VMS type of Au deposit cannot be precluded in the area. The mineralization in the area is largely associated with tonalitic orthogenesis, tonalities, granodiorite, and granitic rocks with Cr-Ni-Co-V forming elemental association. This elemental association is similar to other gold bearing greenstone belts. The style of mineralization in the Dodoma region is similar to other gold deposits within the TC; hence, successful exploration methods in these ancient gold deposits like Geita and Kahama gold deposits can be adopted in the event of any further exploration exercise in the central Dodoma region.

Jul 12, 2021

By J. J. Forbes

Ventilation is the most important safety factor in the production of coal because on it depends the safety, health, and efficiency of those who work underground. Without adequate and efficient means of supplying fresh air to the working faces, mining could not have advanced as it has. The extent of the workings, the increase in mechanization, and the increasing use of electricity are largely responsible for changes in methods of ventialtion. Ventilation in the early, days of coal mining was accomplished by means of a natural draft, created principally by a difference in the weights of columns of air between the intake and return openings: Later the furnace was introduced for the purpose of increasing the quantity of air in circulation. Mines continued to become larger, their output increased, men were employed in greater numbers, and more fresh coal surfaces were exposed. Coal beds near the surface, and practically free from explosive gas became exhausted, and deeper beds that liberated methane were opened as development advanced. Mechanical ventilation became necessary and was first accomplished by disc-type steam driven fans she old-.fashioned steam driven disc fan has generally been supplanted by the powerful electrically operated centrifugal fans in use at modern coal mines. In order to be secure against gas explosions and provide ample fresh air for persons employed in large coal mines, air must be conducted through the mine to all working places and to all other unsealed parts of the mince in sufficient quantities to dilute and render harmless all dangerous and noxious gases.

Jan 1, 1929

How do you think the US Bureau of Mines closing will affect SME? The demise of the bureau represents a challenge, an opportunity and, above all, new responsibilities for our profession. A lot of good professionals are seeking new positions. A lot of worthwhile research is available for transfer to the private sector. Logic dictates that worthwhile projects of any defunded government activities should find support in the private sector. The bureau may be gone but its legacy is deeply rooted in the profession. The bureau’s contributions will be remembered as long as there are mines and miners. Its1994 research program was divided into three major areas: environ-mental technology; health, safety and mining technology; and minerals and materials science. There must be a place in either the government or private sector to continue these worthwhile activities.

Jan 1, 1996

By M. R. Julien, A. Maqsoud, J. Martschuk, B. Bussière

Acid mine drainage (AMD) from mine wastes is one of the most challenging environmental problems currently facing the mining industry. When mining wastes have the potential to produce AMD, the effluents produced have to be managed to meet existing regulations on water quality. The LTA impoundment (property of Barrick Gold Corp.) located near Malartic, Quebec, contains sulphide tailings that have the potential to generate an acidic leachate. The closure option selected by Barrick was to construct a cover with capillary barrier effects (CCBE), in which the moisture- retaining layer is made of non-acid-generating tailings. Since its construction in 1996, the cover has been monitored to evaluate its performance. For that purpose, various parameters have been measured, including the volumetric water content and matric suction in the different layers of the cover. This paper presents some of the main results from the monitoring program that started eight years ago. The results show that the cover is able to maintain a high degree of saturation in its moisture- retaining layer, acting as an oxygen barrier. The actual performance of the CCBE on the flat surface of the 60 ha site is better than expected at the design stage. The only concern with the LTA cover is the effect of slopes that can reduce the performance of the CCBE during dry periods. However, these effects appear only for short periods of time, and are limited to very localized areas, so that they do not significantly affect the overall performance of the CCBE and its ability to limit the production of AMD.

Jan 1, 2006

By Simón Díaz-Quezada, HUMBERTO ESTAY

The heap leaching process has been widely used for recovering different metals since its first application at the end of the 1960s. In Chile, copper production via heap leaching has accounted for between 30 and 40% of annual copper production over the past 10 years. This level of production has been achieved through and supported by the use of a mathematical relation, known as the leaching ratio (LR) or irrigation ratio (IR), which relates operational parameters with metal extraction in a heap leaching operation. This ratio has been used to develop leaching column tests, to scale up results from the laboratory to industrial operations, to design new heap leaching plants, and in metallurgical control and production estimation. In spite of the widespread industrial use of this relation, few scientific studies mention it. This is due to its simplicity and basic theoretical foundations. This disparity between industrial practice and scientific research could lead to operational decisions which lack substantial theoretical support, and to scientific studies which have limited industrial impact. Against this background, several questions arise about the use of the LR: What are the constraints on the use of the LR? Are there practical advantages with respect to reported kinetic models? What is the main reason that industry prefers the use of the LR over kinetic models, which enjoy greater theoretical support? In order to guide its future use, this paper describes the leaching ratio and its current uses and limitations, through a literature review and case studies.

May 2, 2020

By Benjamin W. Haynes

Cement kiln dust (CKD) produced in the contiguous United States and Hawaii was characterized as part of the Bureau of Mines' program in minerals environmental technology. The mineralogical and chemical composition was determined for 113 CKD samples from 102 plants that normally send CKD waste to landfill. Characterization included the determination of 28 elements, 7 anion species, carbon dioxide, noncarbonate carbon, and chemically bound water. Mercury was determined in 15 samples. Interelement correlation coefficients were determined for 23 elements, 5 anions, CO2, noncarbonate carbon, and chemically bound water. To assess the hazardous waste potential of CKD, the U.S. Environmental Protection Agency Extraction Procedure (EP) toxicity test was performed on all 113 CKD samples. All but one sample were in compliance with the test; the noncomplying sample slightly exceeded the EP toxicity test criterion for lead.

Jan 1, 1982

By R. I. Jeffery, J. W. Summers

An account is given of the verification and calibration of a numerical modelling technique that has been developed for the prediction of subsurface strata deformation following the extraction of coal by longwall mining methods.

Jan 4, 1992

By W. K. Cunningham, Edwin A. Gee

"INTRODUCTION This paper is one of many reporting on various aspects of the Bureau of Mines program during World War II directed toward alleviation of shortages in certain critical minerals some of these papers are published as technical papers information circulars, and reports of investigations, of the Bureau of Mines or in technical journals.The investigation described in this report was begun as part of the Bureau, of Mines program to develop acid processes for the extraction of alumina from low-grade bauxites and clays. A domestic shortage of high-grade bauxite suitable for treatment by the Bayer process became acute as a result of World War II; and intensive search for a practical acid process using lower-grade alumina-bearing raw materials was therefore warranted.A survey of the various methods for extraction of alumina from clay has been presented in an early Bureau of Mines publication. 4/ The principal barrier to the successful operation of an acid process has been the difficulty experienced in developing a suitable commercial method for purifying the crude aluminum salts after the clay extraction is complete. Iron salts are the foremost contamination influence. A review of the more prominent procedures that have been proposed for separating iron and aluminum salts can be found in the well-known text on aluminum by Edwards, Frary, and Jeffries. 5/The majority of acid processes to extract alumina from clay employ sulfuric acid as the leaching agent, and the purification is thus reduced to the separation of iron and aluminum, sulfates."

Feb 1, 1948

By G. S. Rice

To those concerned in attaining greater safety to life and incidentally to property in coal mining, the meeting of representatives of the national mine safety research organiza¬ tions of the principal coal-producing countries, which was called by the Safety in Mines Research Board of Great Britain at its experimental station near Buxton, should have deep significance. It is notable, first, because it meant the friendly cooperation of countries not many years ago engaged on either side in the great World War; and second, because of the remarkable degree of agreement in the essential fundamental factors and methods of attaining greater safety in coal mines when it is considered that the questions were approached by different paths and that the applications dealt with widely differing natural conditions and national points of view. Varying views, of course, were held as to the relative importance of certain factors, but the differences were of detail rather than of principle. When the meeting adjourned it was unanimously agreed that such meetings should be continued annually and that the greatest benefit was to be derived by close cooperation in the exchange of data. Belgium, France, Germany, Great Britain, and the United States were represented by one or several members of the respective national research organization. It is of interest to note that this research work in Belgium, France, and Germany is supported directly by na¬ tional organizations of mine operators or owners but placed under a scientist appointed by the respective Government, thus giving the work official standing. In Great Britain the work is carried on by a Government board, consisting of persons connected with the coal¬ mining industry or in mining research, appointed by the Secretary for Mines, to direct the work of research of the Mines Department. It does not, however, come under its inspection service. Its work is supported by a penny-a-ton tax on output of coal. In the United States the mine-safety research work is directly supported by the Federal Government.

Dec 1, 1932

By T. A. Rickard

A knowledge of the principles of punctuation is essential to effective and intelligible writing, for the ease and pleasure of the reader, and even his understanding, may depend upon the choice and the placing of punctuation marks. To 'punctuate' is to mark with stops or points; the word comes from the medieval Latin punctuare (punctuatus), which in turn is derived from the Latin punctum, a point. The purpose of punctuation is to show the manner in which the writing is to be understood; to indicate the relations between parts of a sentence and between successive sentences. To some extent "it does for the eye what vocal stress does for the ear", but especially it marks logical relations. Some punctuation marks, such as those indicating admiration, exclamation, and interrogation, are rhetorical as well as grammatical, but most of the common ones are logical, or grammatical. My discussion will be confined to grammatical punctuation in ordinary writing. .'The problem of punctuation in text matter", as George Summey * says, "is to employ words, points, and paragraph breaks in such a way as to achieve at the same time clearness; proper distribution of emphasis, and the desired kind of movement." The criticism of the punctuation of a sentence or of a group of sentences is not final until the context, within the paragraph, is read. A paragraph is a sentence or a group of sentences forming an independent unit of the composition; it represents a unit of thought. A multiplicity of paragraphs produces a choppy effect; 'on the other hand, paragraphs of. excessive length are tiresome, because the belaboring of one unit of thought wearies the reader. The aim should be to

Jan 1, 1931