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By Patiño E

Bioleaching is an established technology for the pre-treatment of refractory gold ores and concentrates and the leaching of whole ore copper heaps. In many cases, it offers economic, environmental and technical advantages over pressure oxidation and roasting. However for bioleaching to compete successfully with others pre-treatment processes it needs to be optimized with regard to the parameters that affect the bioleaching reactions and the growth of the microorganism involved. In this sense, this paper focus on the thermodynamic approach applied in bioleaching through of the definition of the growth system and it is thermodynamics analysis, the effect of heat production and energy dissipation on growth and thermodynamic analysis of growth kinetics and the effect of nonstandard conditions.

Sep 12, 2005

By C. B. Manula

This report is mainly concerned with the modification and development of a users manual for the Open-Pit Materials Handling Simulator (OPMHS) developed at Penn State. Model Modifications included the introduction of a free-format input, the application of a Weibull random generator, facilities to stochastically simulate shovel-dragline operations, and routines to increase the flexibility in making truck assignments. At the same time, core storage requirements and execution times were minimized and all P.S.U. conventions were removed to allow operation on other computing systems.

Jan 1, 1976

By Charles H. Foreman

This paper describing the mining practice of the Hecla and Star mines, both located at Burke, Idaho, is one of a series being prepared by the Bureau of Mines on mining practices, methods, and costs in the various mining districts of the United States. It is partly a revision of articles by the author appearing in volume 72 of the Transactions of the American Institute of Mining Engineers, published in 1925, and in the June 1928, issue of the American Mining Congress Journal. About 26,000 tons per month of lead ore is produced at the Hecla mine. Costs at the mine are given for the year 1928. Stoping operations in the Star mine have covered such a short period, during which time the abnormal expenses of starting were incurred, that they are not given in this paper.

Jan 1, 1930

By G. L. Neumann

Owing to the need for additional sources of supply of both zinc and lead following World War II, the Bureau of Mines investigated many abandoned lead-zinc mines in the eastern United States. A series of shallow veins in south-western St. Lawrence County has long been a subject of speculation. These veins, which average about 4 feet in width and cut across the bedding of the country rock at right angles, are filled with calcite-carrying galena and sphalerite. The deposits have been worked sporadically during the last 115 years. From 1837 to 1852 the Coal Hill, the North, and the Victoria mines near the village of Rossie were at their peak of activity. Other calcite veins were prospected and a small production was realized. The Bureau of Mines began diamond drilling May 1, 1950, under the general supervision of McHenry Mosier, chief, Mining Branch, Bureau of Mines, Region VIII, and under the immediate supervision of the author) who was project engineer, following the preliminary examination by Robert S. Sanford. A total of 3,870.2 feet was drilled in 18 holes on four of the numerous deposits scattered over Macomb and Rossie townships. Drilling was completed September 21, 1950.

Jan 1, 1952

By Harvey W. Parker

Our industry has developed to the skilled, experienced and productive industry that we now enjoy as a result of the visions of great engineers throughout history, but, in particular for their visions in the last 1 centuries. Unfortunately for our forefathers, the technology lagged so far behind that these exceptional visions could not be realized for decades, sometimes for a century. All that has changed in recent time and many bold and visionary projects can now be constructed and operated because of dramatic advances in technology. Before, say, 1950, tunnel technology developed very slowly. However, technology is now developing at such a fast rate that planners and decision makers are challenged to stay ahead. Moreover, new technology will develop during the lifetime of any project that can dramatically improve under-ground space projects. One of the best examples of this technological advancement is that of closed-face TBMs which now make tunneling feasible in previously impossible ground conditions. Since it usually takes a decade or more to plan, overcome environmental and political issues, construct, and put into service major projects, planners and designers are challenged by the changes in technology that occurs during the long time span of planning and construction. This is particularly true of large infrastructure projects such as transportation, water and wastewater systems and other major underground schemes. Also, since the serviceable life of many of these tunnels is often over one century, planners must consider not only lessons learned from the past but also what new concepts and innovations may develop over an extremely long time. These and other issues create a great challenge to planners and illustrate the great importance of careful but creative vision and flexibility during planning of long-term tunnel and underground space projects.

Jan 1, 2008

By G Smart, D Ward, J Grace

Ridgeway Gold Mine is part of Cadia Valley Operations which is wholly owned and managed by Newcrest Mining Limited. It is an underground sublevel cave (SLC) operation mining approximately 5 Mt per annum. Ore control systems at Ridgeway have been designed to deliver gold and copper metal production through focussing on the ore characteristics that impact on mine and mill performance and ultimately metal delivery. This is achieved using data collection and management systems which allow data to be collected digitally with æat captureÆ validation routines. These data form the basis for forecasting and on-going systems analysis which aim to accurately assess local in situ and drawn ore characteristics. Physical attributes of ore such as draw characteristics, brow conditions, visual grade estimates and draw point sampling are routinely recorded. Ore tracking and accounting systems monitor gold and copper grades, copper mineralogy, host lithology and ore sizing. These factors have material impacts on concentrator throughput and metal recovery. Draw point recovered grades are routinely reconciled back to design data to monitor and assess draw performance. Statistical variance controls are also employed to analyse mine and plant performance and guide actions.

Jan 1, 2003

The revised inspection standards or recommendations herein have been prepared for use in Federal inspection of bituminous-coal and lignite mines. They succeed a compilation of similar standards published as Bureau of Mines Information Circular 7268 in December 1943 and employed as a guide in Federal inspections since that time. Important alterations and additions have been made because of changes in mining, practice and temporary shortages of some safety equipment; moreover, several previous standards have been found not generally applicable and have accordingly been deleted. Mining methods and equipment continue to change, and new hazards and new safeguards are introduced. Consequently, these standards are subject to revision from time to time. Questions from the coal-mining industry regarding these standards and suggestions as to changes and additions thereto will be welcomed and considered carefully when the next revision is made. Many constructive criticisms from the mining industry have been considered in preparing this edition.

Jan 1, 1945

By S. S. Indi, D. Santhiya, S. Subramanian, K. A. Natarajan

The interaction of sphalerite- and galena-adapted Bacillus polymyxa (B. polymyxa) cells with sphalerite and galena has been investigated through adsorption, electrokinetic and flotation studies. The amount of sphalerite-adapted cells adsorbed onto sphalerite and galena is found to decrease with increase in pH. On the other hand, the adsorption density of galena-adapted cells onto galena shows a feeble maximum around pH 8, and the amount adsorbed is marginally higher in the pH range of 8 . 11.5. In the case of sphalerite the amount adsorbed is higher in the pH range of 5 to 7. The adsorption density of both the adapted cells is higher for galena vis-à-vis sphalerite. Electrokinetic studies indicate significant surface chemical changes on the chosen sulphide minerals and the bacterial cells, consequent to microbe-mineral interactions. Selective flotation tests on a synthetic mixture of galena and sphalerite confirm that sphalerite could be preferentially floated from galena, using galena-adapted cells, but not with the sphalerite-adapted cells. The cells adapted to galena assay a higher polysaccharide content and are more hydrophilic, while the sphalerite-adapted cells have a higher protein content and possess greater hydrophobicity. Transmission electron microscopic studies have provided evidence in support of the differences between the cell surface characteristics of sphaleriteand galena-adapted cells. Possible mechanisms of interaction between the minerals and the bacterial cells are discussed.

Jan 1, 2003

By H. D. Van Veldhuizen

The Multilateral Investment Guarantee Agency(MIGA) is part of the World Bank Group, and has as its mission the facilitation of foreign direct investment by providing political risk insurance (guarantees) to foreign investors and lenders. As a development institution, MIGA is required to ensure that the projects that it insures will bring development benefits to the host country. Demonstration of this includes review and analysis of the environmental and social soundness of a prospective investment. Environmental guidelines and policies developed by the World Bank Group are important components both in analyzing the environmental and social soundness of a prospective investment and in risk management. MIGA has recently formalized and adopted environmental assessment and disclosure policies. The approach taken by MIGA to environmental review of investments and implementation of these policies is described in this paper.

Jan 1, 2000

By Eugene Guccione

The US mining industry today is fighting for its existence. We are plagued by the shortage of materials, of equipment, of fuels, of capital, of manpower. If we solve those shortages, we are then frustrated in our attempts to open a new mine or, perish the thought, a new smelter. If we manage to make a profit, demagogues will accuse us of stealing from consumers; and, if we do not make a profit and have to shut down, the same demagogues will accuse us of creating unemployment. Meanwhile, in every aspect of our business - from research, exploration and development, to production, marketing and selling - we are hindered in every way by the bipartisan mismanagement and crippling controls of a government bureaucracy gone amok. We are fighting a war on every front. Some of you realize that ours is a war of ideas. In order to win, our industry must make its ideas heard. But to be heard, we must have something to say - which means: we must know our case logically and consistently, all the way down to essential principles. A principle is a primary truth applicable to a great number of instances. A principle is like a road map: it shows you all the possible alternatives for getting from where you are to where you want to go. Although practically everybody recognizes the usefulness of a map and the need to consult it to find the best way' to get from one city to another, most people are not as careful in charting the course of their life, or the course of their industry, or the course of their nation. And so they act blindly, at random, by the whim of the moment, and get nowhere fast.

Jan 1, 1975

By Oliver C. Ralston

The minerals that enter welding-rod coatings and fluxes are the main subject of this report. Few mineral producers know just what minerals and what grades and quantities of minerals are required by the welding trade, and it is for their information that this report has been prepared. The various methods of welding are discussed extensively enough to inform this type of audience. Specialists in welding probably will find little on welding that is of value to them, but they may learn something more about the minerals or mineral products that they use. The authors did not find it easy to prepare this publication, and any needed corrections will be welcomed. Regarding welding, research, Jenks4/ 1 points out that while the process of welding in simple in operation, the phenomena attending its use are extremely complicated, and the efficient and safe use of welding requires an understanding thereof. Although the fluxes and the coatings used have solved many problems, many other problems require the joint effort of the whole industry; therefore, it is hoped that this report will be found of practical value.

Jan 1, 1940

By Jay S. Gunasekera

Since great emphasis is being placed on the manufacturing science and processing science programs in the Department of Defence and other government research agencies and industries; currently, extensive research on computer aided design(CAD)/ computer aided manufacturing (CAM)/ and computer aided engineering (CAE) is being conducted at Ohio University (OU) . OU has invested over a million dollars in CAD/CAM hardware and software. Design and analysis packages like ALPID, NIKE, STREAM, SHEAR, POLY_FLON, RINGROLL have been developed or modified at OUusing finite element method, finite difference techniques or enhanced slab analysis. Packages like ABAQUS, FLUENT, and NASTRAN have been extensively used.

Jan 1, 1990

By G. E. McElroy

The purpose of tins paper is not to present new date on the pressure losses due to bends and chances of area in mine openings through which air flows, but rather to correlate existing data, determined mainly on small duct systems and expressed in a variety of ways, according to uniform methods that facilitate their use in pressure-loss computations. These are required in such, air-flow problems as determining the quantity that will flow through is mine openings under a certain pressure difference or, conversely, the pressure difference that will be required to maintain a certain rate of flow. Air flowing through h ducts, such as mine airways, encounters resistance to flow due to interference of the individual air streams with each other caused by the wall surfaces. The result is that part of the kinetic energy of the flowing stream is converted to heat; and constant renewal of the kinetic energy from the total energy of the flow is required to maintain it. This process manifests itself by a decrease of the total pressure (static pressure plus velocity pressure; of the air in the direction of flow; in order that flow pray occur, there must necessarily be a differences in total pressure between the two cads of the air-ay equivalent to the pressure losses occasioned by the flow, which automatically adjusts itself in magnitude to the pressure difference maintained.

Jan 1, 1932

By R. P. Stahura

Conveyors are the lifeline of mining and processing operations. They continuously supply materials to and carry finished products and waste away from operations. When conveyors are running at less than maximum efficiency, the operation's productivity is in trouble. Inefficient conveyors suffer carryback, leading to the buildup of materials on idlers and other expensive components. They spill and leak material at loading zones and conveyor transfer points. This causes accumulations that can damage the belt, wear moving components and increase both clean-up labor and maintenance expenses. They wander or mistrack, spilling material and endangering personnel and conveyor components. And through these inefficiencies, they multiply the operation's hidden costs. These added expenses occur in lost production, increased downtime for service and maintenance and replacement costs for prematurely worn equip¬ment. In addition, the attitude that inefficiency is "good enough" is recognized elsewhere in the organization. As a result, other departments relax or operate at less than peak performance. Quality goes down along with employee morale. Costs of inefficient conveyors A key to efficiency is handling a product as few times as is necessary. That means conveyors should be loaded, track true to the unloading point and then be unloaded, all without material escape or waste motion. An inefficient conveyor is often signaled by accumulations of DURT - material that has escaped from the system and is now at large in the plant. This DURT adds costs to an operation that are uncounted and, perhaps, uncountable.

Jan 1, 1992

By A. J. Farstad

The principle objective of the research effort described herein was to identify as rapidly as possible a practical trapped miner location system. Much effort has been expended in the past on the development of a highly sophisticated seismic location system [1] for trapped miners. Field tests of this system have shown that the location accuracy is limited by a combination of seismic velocity anomalies, timing errors, and in general by the relatively weak nature of the signals received at the surface. It was first felt that similar propagation anomalies would be experienced by electromagnetic systems, but to a greater extent than the seismic. However, preliminary tests performed by Westinghouse on the Operations and Maintenance Program, Contract No. H0210063 in 1971 and 1972, indicated that an electromagnetic solution to the location problem may be more feasible than a seismic solution. Thus a more concentrated effort was launched in 1972 and 1973 to more completely determine the feasibility of electromagnetic location systems for trapped miners. Two different approaches to the location problem were undertaken on this program: (1) A pulsed electromagnetic system was developed by the Special Systems Division of Westinghouse in Baltimore, and (2) a Continuous Wave (CW) System was developed by Westinghouse Georesearch Laboratory (WGL) in Boulder, Colorado. Part I of this report will deal only with the development and results of CW Location System developed by WGL. The CW Location System was field tested at three eastern coal mines and at one western hardrock mine. The maximum overburden depth penetrated during these tests was 990 feet at the Robena No. 4 mine near Waynesburg, Pennsylvania. The earth conductivity at this mine was measured to be 1. 1X102 mhos/m, which combined with the deep overburden make this mine representative of expected worst case conditions for a coal mine EM location exercise.

Jan 1, 1973

By J. A. Kost

The objectives of this contract were to determine the amount, size, and deposition of float coal dust (74 x 10 microns) generated during the mining and transporting of coal in underground U.S. mining operations. Rock dust distributed by trickle dusters was also sampled. In addition to four belt-transfer points, two continuous and two conventional mining sections were sampled at five mines located in Pennsylvania, West Virginia, Kentucky, and Illinois. Float-dust samples were collected on deposition pans; total airborne dust was collected with MSA Model C personal samplers equipped with Unico filter casettes; Andersen cascade impactors provided relative size distributions of the samples. Production, airflow, and water flow were monitored to examine their effect on dust levels.

Jan 1, 1981

By A. S. Macfarlane

Over the last few years, and especially the last few months, issues relating to Corporate Governance in industry in general, and the Minerals industry in particular, have become increasingly topical, as a result of a number of scandals and failures. The development of International and National Codes for the reporting of Mineral Resources and Reserves began some years ago, and has been followed by more stringent Listing Rules for the Securities Exchanges, as well as more standardised formats and protocols for financial reporting of assets and activities. More recently, some countries have adopted Codes for the Valuation of Mineral Properties, which have focussed on standardisation of valuation approaches to be adopted, and the qualifications of people deemed competent to sign off such valuations. This process has not been without criticism, the main criticism being the proliferation of local standards and regulations, which are often difficult to apply and regulate, or which are too prescriptive for multinational mining companies to deal with. In South Africa, these concerns have been recognised, while at the same time a need has been identified to establish a Code which could be applied to South Africa, and the African continent as a whole. Such a development would necessitate that the Code satisfies the needs of the continent, but in a global context. This global context has already been set by the activities of the International Organisation of Securities Commissions, the International Valuations Standards Committee and the International Accounting Standards Board. This paper explains the progress and process that has been established in South Africa for this purpose, and highlights the key issues which are open to public debate, so that the process is inclusive and transparent, whilst at the same time it is consistent with international time frames, and provides a deliverable product that meets the desired objectives.

Jan 1, 2004

By H. R. Taylor

The history and development of this property is more or less familiar to nearly everyone connected with the mining industry, so that only a brief outline of the more important facts will be given in this article. In 1916, a small pilot mill was constructed by the British Columbia Copper Company at Copper Mountain, and during 1916 and 1917 test work was conducted to determine the possibility of concentrating the ore and also to work out a suitable flow-sheet. In the spring of 1917, the location of a mill site at Allen by, which is about 8,% miles from Copper Mountain, and near the Similkameen river, was decided on, and the designing of a 2,000-ton plant was then worked out by Bradley, Bruff and Labarthe. Early in 1918, the actual construction of the concentrator began, and, after considerable labour difficulties, it was completed in 1920. During this period of construction, the West Kootenay Power Company ran a 60,000-volt power line over from Greenwood, a distance of 102 miles, and also built a sub-station at Allenby to take care of the mine and mill. The concentrator was started up on October 20th, 1920, and ran until December 11th, 1920, a total of 18,354 tons of ore being milled. The results of this short period of operation were encouraging, but, due to tlie prevailing low price of copper and high wages, it was necessary to shut down until a more favourable time. During the latter half of 1923, some work was done on remodelling the mill. This work continued until January 8th, 1924, when it was suspended.

Jan 1, 1929

By H. DeWitt Smith

THE mine operated by the United Verde Copper Co. is situated near Jerome, Ariz., on the eastern flank of the Black Hills, at an elevation of approximately 5500 ft. (1676 m.) above sea level. The mine and the town of Jerome are located on a steep hillside, which slopes rapidly to the valley of the Verde River. The smelter town of Clarkdale is situated in the Verde valley 4.1 mi. (6.5 km.) distant in an air line from Jerome, and at an elevation of 3560 ft. The two towns are connected by the standard-gage railroad of the Verde Tunnel & Smelter R. R., a subsidiary of the United Verde Copper Co. This road is 11 mi. long and has a compensated 4 per cent. grade. At Clarkdale, it connects with the Verde Valley branch of the Santa Fe R. R. The narrow-gage (36-in.) line of the United Verde & Pacific Ry. was, until 1919, Jerome's only rail connection with a main trunk line. This road connects with a branch line of the Santa Fe system at Jerome Junction, after traversing 26 mi. of mountainous country. From the time of its location, in 1876, until its purchase by Senator W. A. Clark, of Montana, in 1889, the United Verde mine was worked on a small scale and shipments of high-grade gold-silver ore were made from the surface workings. Until 1894, when the narrow-gage railroad to

Jan 8, 1920

By Lewis C. Karrick, Martin J. Gavin

"Introduction.The theory of fractional ""education"" of oil from oil shale has been used by several inventors as the basis for the design of retorts for the production of oil from the oil shales of the United States. The term fractional ""education"" gives expression to the rather common belief that when an oil shales is heated it produces light, low-boiling oils as low temperatures, and increasingly heavier, higher-boiling oils as the temperature of retort¬ing rises. The theory evidently had its origin in the fact that crude petroleum may be fractionally distilled, yielding light oils at low distillation temperatures, and heavier oils as the distillation temperature increases is as, gasoline is produced from petroleum at relatively low temperatures, kerosene at higher temperature, and heavier products such as gas-oil and lubricating distillation at still higher temperatures.The writers have examined several oil-shale retorts designed to take advantage of the belief that crude, and in some cases refined, gasoline can be recovered from the shale at low temperatures; kerosene at higher temperat.res, and so on. Such retorts are usually designed to operate continuously and have several vapor-pipes lending from them at differing intervals and passing to separate condensers. Designers of such retorts repeat that the distillate from the low-temperature parts of the retort will be gasoline, and that as the shale passes to zones of increasingly higher temperatures, the vapor lines lending from these zones rill remove increasingly heavier products such as kerosene, gas-oil etc."

Mar 1, 1924