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By Robert W. Bartlett

Pretreatment of sulfidic refractory gold ore by biooxidation in coarse-crushed ore heaps is a promising new technology, especially for low-grade ores that cannot afford pressure leaching or roasting. An algebraic equation for determining the economically optimum biooxidation of the sulfide minerals in the ore is provided that is based on the empirical biooxidation rate constant for the ore, the project's financial discount rate, the ore grades of both refractory and non-refractory gold, and the gold price. Then, the economically optimum duration of bioheap pretreatment, t$, is determined from its logarithmic relation to the optimum fractional extent of ore biooxidation, F$, through the ore's biooxidation rate constant. In doing so, it is assumed that the ore is adequately crushed and amenable to bioheap pretreatment and that the cumulative oxidation of the ore with time is known from ore testing so that the rate constant can be determined.

Jan 1, 1995

By Kenneth W. Torpey, James G. Ball, Richard F. Flanagan, David S. McAllister

INTRODUCTION Under a Federal grant by the Urban Mass Transit Administration (UMTA) (80%), and sponsored by the State of New York (200), Niagara Frontier Transportation Authority is constructing a 10.3 km (6.4 mile) light rail rapid transit system in Buffalo, New York. The $450 million project, which began construction in the Spring of 1979, is unique in rail transit alignment designs in the U.S.A. and the first predominantly underground light rail system in North America. The Buffalo project is unique in that the first phase of the expandable system follows the alignment of Main Street and is on the surface in a proposed 1.6 km (1.0 mile) pedestrian mall in the downtown business district. The alignment then progresses northward into a cut-and-cover portal and standard double-box configuration for 2.74 km (1.7 miles) at a depth of 9.1-10.7 m (30-35 ft) and subsequently drops into bedrock at depths of 18.3-27.4 m (60 to 90 ft). The 5.63 km (3.5 mile) rock tunnel section consists of two single tunnels 4.88 m (16.0 ft) nominal finished diam. and includes five stations. The rock tunnel line section was divided into a north and south contract of 2 316 m (7,600 ft) and 3 243 m (10,640 ft), respectively. Due to the existing surface facilities and the future station locations, the line tunnel contracts differed considerably in their shaft access

Jan 1, 1981

By Robert L. Major

The expanded role which coal has been assigned in the energy future of the United States has raised numerous policy questions. The very complexity of these questions makes them suitable to analysis by econometric models. However, as the Wall Street Journal indicated in its recent article, business' success with such models have been mixed. I have been asked to present my views as to how coal producers can use such models and in what ways the industry is likely to be impacted by such models. I do not presume to speak for the whole coal industry, but only to share with you the personal observations of one who has worked "both sides of the street", having been employed' both by government and a consulting firm prior to joining the coal industry. In my opinion, the use of econometric models to analyze the coal industry will impact the coal producers in two main ways. First, their use by government will have a profound impact on future government policies related to the mining, transportation and utilization of coal. Second, such models, when properly calibrated and refined, may become useful tools for the coal producers in doing market research and long-range planning. While the former has already begun to impact on the operating environment or the coal industry, the latter is still in the embryo stage.

Jan 1, 1977

By Andrzej Wala, Waclaw Dziurzynski, Janusz Tracz

Recent advancements in computer hardware have led to the development of new ventilation planning software for PC's. These programs now can be run more quickly and can display their outputs with graphical techniques. Only a few of the existing programs have the capability to display the output data graphically on plotters. Graphical presentation of ventilation simulation data is essential for quick and sure comparisons of alternative analyses. Recently a noticeable growth has occurred in the application of graphics for display and interpretation of the data that have been developed by simulation procedures. The process of mine ventilation network analyses used for planning and design can benefit from this development. The authors describe and present graphics-assisted software that has been developed to work with a mine ventilation simulation program. This software has some of the following features: - graphic editor on screen, - graphical display of output data on screen (EGA, VGA), - graphical display on plotter or printer, - scaling capability (desired part of the entire schematic can be displayed), and - such values as flow, pressure loss, gas concentration for branches, and pressure and elevation at junctions can be presented as labels.

Jan 1, 1991

By Kim W. Wright

Introduction Mining operations require maps for each phase of project development. Engineering plans, cross-sections, and isometric drawings are also needed. Maps are used for geologic interpretation, reserve estimation, permitting, property acquisition, site studies, development work, and production. Maps and drawings are essential to mining. They provide needed information. Generating these products, however, requires many manhours. The filing and organization of maps and drawings is cumbersome, due to their size. Major map changes can necessitate the production of entirely new documents and, thus, additional manhours. The volume of maps and drawings generated in the life of a single project can be extensive. For example, some utility companies have data bases containing more than a million individual maps (one reported eight million). These problems were considered necessary evils in the past. Now, with the automation of map and drawing production, improvements can be realized. Computer-aided mapping and design offers a new approach for the production, management, and storage of drawings and maps. This approach promises benefits in time management, productivity, efficiency, and flexibility. In all economic projects, the bottom line is cost reduction. And implementing computer-based mapping and design techniques can lower costs and increase project profitability. AM/FM/CAD/CAM Automated Mapping/Facility Management (AM/FM) and Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) are becoming buzz words in the engineering world. Most relevant to mining are the concepts of AM and CAD. These terms relate to the application of computers, specifically computer graphic technology, to mapping and design. CAD refers primarily to the design of components and structures in two and three dimensions. But it can apply to the three dimensional modeling of mine workings, ore bodies, and geologic structures AM refers to the automation of conventional map production. AM/CAD systems use computers to store, manipulate, produce, and update drawings and maps in two and three dimensions. Ideally, the calculating capabilities of computers are also used in conjunction with design and drawing generation, offering capabilities not available with conventional, manual mapping and design processes. To better understand concepts associated with AM and CAD applications, the understanding of a few computer-related terms is necessary. Table 1 explains some of these terms. System Features The capabilities of AM/CAD systems are based on viewing transformations. These are the basic, manipulative tools by which AM/CAD packages generate visual representations of data. Examples include the rotation of a three-dimensional object through space, the expansion or contraction of maps to fit a given scale, enlargements of small areas on maps or drawings for detailed viewing, and the generation of cross-sections from three dimensional data. AM/CAD systems incorporate data base management in their architecture. This allows a user to modify, move, delete, or manipu-

Jan 6, 1985

By Thomas Pollard

It is truly remarkable how the image of longwall as a method of mining has changed. Between 1920 and 19609 viewed on a world wide basis, longwall was regarded as a' system for difficult and deep conditions and associated with intensive labour extraction. Today the world looks on longwall in the hope that it can produce the next really big break through in productivity, Three correlated machinery developments have made this possible, but it is not only the machinery developments, interesting though these be in themselves, but together with developments in control systems of these machines that longwall now looks so much more attractive, The machinery concerned is, of courses:- 1. The Anderton Shearer Loader - A miner that takes a narrow strip off the, face at rates acceptable to modern mining engineers. 2. An Armoured Flexible, Conveyor which can be kept in close contact with the face and still convey coal as it is snaked over to the faces 3. Powered support systems which can be mechanised and controlled with reliability at any distance from the individual support itself.

Jan 1, 1964

By William J. Shampine

This map shows general trends of the chloride concentration of water in the upper part of the Floridan aquifer. Below this part of the aquifer, high chloride water can be found everywhere in the State. The accompanying cross section shows the depth to salty water across central Florida. In the center of Florida, fresh water may be found as deep as 2.000 feet, whereas, along the coast it may extend no deeper than about 200 feet. Chloride concentration in small local areas may deviate from the values represented on both the cross section and the main map. This map shows general trends of the chloride concentration of water in the upper part of the Floridan aquifer. Below this part of the aquifer, high chloride water can be found everywhere in the State. The accompanying cross section shows the depth to salty water across central Florida. In the center of Florida, fresh water may be found as deep as 2.000 feet, whereas, along the coast it may extend no deeper than about 200 feet. Chloride concentration in small local areas may deviate from the values represented on both the cross section and the main map.

Jan 1, 1966

By I. G. Ediz, D. W. Dixon, W. M. Fidler

In this paper a new method for the arresting of tunnel explosions is presented. In the proposed technique, the on coming explosion is detected by a pressure sensitive device by a pre-determined rise in static pressure. The sensor then triggers a mechanism which causes the explosion door to be closed in a specially constructed concrete barrier zone. The doors are of a special construction and consist of perforated steel plates that allow part of the blast wave to be transmitted but do not allow the passage of the flame. A number of design parameters have been identified, including: the likely amplitudes of the transmitted/reflected pressure waves that would govern the explosion door pressure loading; thickness of the perforated steel packages; perforation dimensions; heat transfer across the door and other factors.

Jan 1, 1995

By Xinming Lu

In this paper, we use a new kind of fan charateristic curve instead of the common quadratic function, and give the existence and the uniqueness of the solutions to the ventilation network controlling equations, so that the existence and the uniqueness of the solutions for the natural air distributting problem can be conveniently given. We also give a conjugate gradient method with the global convergence to solve the equations having the unique solution. Because we adopt a very efficient technique of one dimensional search (or linear search) in this method, the method can quickly solve a lot of problems, especially in large scale problems. The second part of this paper is the establishment of the model of the constrained quadratic programming for the measurement adjustment of mine ventilation network. We give the algorithm to solve this model as well. The two algorithms given above have been realized in the mic-computer MC-68000 with Fortran codes, and the numerical results are satisfactory.

Jan 1, 1991

By William Cass, Ellen Caftel Turcotte

The Elliot Lake Centre was established in 1965 as an independent Centre for Continuing Education offering a variety of adult education services. In 1976 all retraining and community college type activities were transferred to the Sault College of Applied Arts and Technology which had opened a branch campus in Elliot Lake. Upon the completion of this transfer, the Elliot Lake Centre was then contracted in 1977 by the Canada Centre for Mineral and Energy Technology to study the feasibility of establishing a research and information institute dealing with various health and safety concerns of the uranium worker. By late 1980, a federal charter was granted for the establishment of the Canadian Institute for Radiation Safety, made possible through the cooperative efforts of the Governments of Canada and Ontario, the Ontario uranium mining and refining companies, and the Elliot Lake Centre. On 1 April 1981 the Institute officially began operations. PROGRAM DEVELOPMENT AND COORDINATION In May 1978 the Elliot Lake Centre initiated a voluntary sputum cytology program for uranium workers. This program was financed by the Ontario uranium mining companies: Agnew Lake Mines Limited near Sudbury; Madawaska Mines Limited in Bancroft, and Denison Mines Limited and Rio Algom Limited in Elliot Lake. In 1981 additional funding was granted by Eldorado Nuclear Limited for a small group of employees at the company's uranium refinery in Port Hope, Ontario. Initially in 1978, program participants were accepted according to length of employment, radiation exposure levels (calculated in working level months) and/or smoking history. These restrictions were abolished within a few months and all uranium workers were encouraged to participate. From 1978 to 1979 the sputum cytology program was medically directed by personnel from the Montreal Cancer Institute. Until 1979 all data maintenance for the program was performed manually, however the effort required to sustain the system increased significantly as the number of participants grew. In September 1979 the Division of Thoracic Surgery at the Toronto General Hospital, under the direction of Dr. F.G. Pearson, submitted a proposal to the Elliot Lake Centre to develop a data processing system to help coordinate the surveillance program. In October 1979, Dr. Pearson became the new Project Director. Director of the Cytology Program is Dr. D.W. Thompson of the University of Toronto who is responsible for all cytologic analyses. Developmental work to establish the new surveillance system was initiated in January 1980 and became fully operational at the beginning of March 1981. The following sections describe the Elliot Lake operations of the sputum cytology program now conducted by the Canadian Institute for Radiation Safety. PROGRAM PARTICIPATION As of 1 September 1981 the sputum cytology program has 518 participants enrolled. Eligibility is restricted only to a willingness to participate and the ability of an individual to produce adequate sputum samples. Each participant registers for the program at the Institute and is given personal instruction on methods of sputum collection. The majority of the participants in this program are employed by the uranium mining industry; some work for firms which are contracted by the larger companies. Many participants are either retired from the work force or receive disability pensions or workmen's compensation benefits. Other participants have been employed in the uranium mining industry and have since gone on to other employment; some work for various federal and provincial governmental agencies concerned with the mining industry. Some participants are referred to the program by their family physicians because of smoking histories and/or various respiratory conditions. A small number of these individuals have never been involved in the mining industry at all. A chart describing program participation by employment is found in Appendix 1. PROGRAM REGISTRATION In the Elliot Lake area, persons interested in registering in the program are required to go directly to the Sputum Cytology office located at the Canadian Institute for Radiation Safety. Each individual is interviewed personally by the Program Officer. For the employees of Agnew Lake Mines, Madawaska Mines and the Port Hope refinery of Eldorado Nuclear Limited, registration is possible during the Program Officer's semi-annual on-sitevisits. Participants are assigned, in chronological order, "program numbers" for easier identification. File labels are color-coded according to place of residence or, in some instances, place of employment. Each file is stamped with the date each sample bottle is distributed. A file contains: all original test results, a completed registration

Jan 1, 1981

?Energy-related systems: wind, solar, electric are typically materials intensive. As new technologies are widely deployed, significant quantities of the elements required to manufacture them will be needed. However, many of these unfamiliar elements are not presently mined, refined or traded in large quantities, and, as a result, their availability might be constrained by many complex factors. A shortage of these ?energy-critical elements? could significantly inhibit the adoption of otherwise game-changing energy technologies. This, in turn, would limit the competitiveness of the U.S. industries and the domestic scientific enterprises and, eventually, diminish the quality of life in the US.? -Energy Critical Elements: Securing Materials for Emerging Technologies?- American Physical Society, 2011.

Jan 1, 2012

By V. Svalbonas

With the occurrences of serious mill structural failures on both ball and primary mills, the mining industry has entered the era of detailed fabrication specifications. Such specifications, however, have been developed as individual entities, often by people not related to the mill design function. Therefore, there has been no effort to relate mill failure or safety to the existence or elimination of specific fabrication flaws; that is, no cause-effect failure relationships have been developed. The omission of this step produces a specification which can be termed uneconomical at best. The present paper attempts to fill this void, by reviewing methods for design consideration of flawed structures, and describing experimental tests used to tie such data to a meaningful quality assurance program in fabrication.

Jan 1, 1985

By A. A. Mular

Examining a typical curriculum for mineral process engineers shows that traditional subjects remain important, namely, engineering, earth and basic sciences, mathematics and mineral proc¬essing technology. However, Table I shows additional subjects that may be woven into a modern curriculum, because of micro- and macro-engineering advances over the years. The ways to incorporate these subjects into the curriculum will vary from school to school. Such changes are in response to evolutionary technological and political needs as determined by society and business. Beginning with the 1950s, engineering empiricism was strengthened through micro-engineering, where fundamentals and mechanism serve as foundations. Scientific apparatus unique to the basic sciences (Zeta meter, FTIR spectroscope) was adapted to test new hypotheses. Coincidentally, as computers became more available, complex differential

Jan 1, 1992

By Harold V. Fairbanks

This investigation included a study of three different methods for the acoustic drying of ultrafine coals. Ultrafine coal being defined as coal which passes through a 100 mesh sieve. The first method employed stationary drying of small coal samples in sound fields having frequencies of 12,000 cps and 20,000 cps. Sound intensities up to 150 db were used. The second method employed the use of rotary drying kilns. The effect of such variables as temperature, sound intensity, coal feed rate, air flow rate, and initial moisture content were studied. The third method employed the use of a multi-tiered, vibrating screen dryer. The effect of initial moisture content and residence time were studied.

Jan 1, 1970

By Peter H. Grimley

It is important to realize that lending institutions have a very different risk-profile from that of an equity investor. For bank financing, a feasibility study must address the concerns of the lender and these can be summarized under the four 'PI Is: Project, Performance, Product and People. Generally, feasibility studies focus on the measurable project risks associated with a new venture, but frequently insufficient emphasis is placed on key risk areas such as ore grade and metallurgical recovery. Before accepting full or even partial non-recourse risk, financial institutions will demand evidence that the project was constructed according to specifications and within budget and that its Performance within agreed limits has been demonstrated. Product risk should be discussed in detail in any feasibility study. For industrial minerals, penetration of the market can be critical to success and for commodities with volatile prices, the sensitivity of the cash flow to a range of prices should be carried out. Methods of reducing price risk such as long term contracts or, in the case of gold, forward selling should be carefully evaluated. The People risk is rarely discussed in feasibility studies, but can be a key element. Few projects turn out to be faithful copies of the study and the ability of the operator to identify

Jan 1, 1988

By F. Mauviel, J. Bernard, G. Herrouin, J. P. Lenoble, C. Charles, B. Taine

Manganese nodule projects were quite fashionable during the 1970s. At the beginning of the 1980s, low metal prices led to an almost complete reduction of such activities; however, the Law of the Sea incited the countries that signed it to build a strategy for this ocean resource. Gemonod was created in France in 1984 with a four-year mission. This paper presents the results of its program devoted to the technical and economic studies of nodule exploitation. A commercial mining system is presented. The nodules would be collected by a self-propelled miner and lifted hydraulically through a rigid pipestring. A complete optimized scenario has been built taking into account offshore mining, ore transfer at sea, transportation and processing to analyze the profitability of the project. Considering an average conservative basis for metal prices, after a deep analysis of the market, the return rate of investment of the project appears fairly interesting. These results are new and are explained in comparison with previous foreign studies. These results must not hide the innovative nature of the project nor the associated risks. This is why a mining pilot is required and has been specified by Gemonod.

Jan 1, 1991

By B. Stewart, J. R. Warneke

The productivity of underground mines has increased dramatically since the introduction of continuous miners. A variety of new hazards have developed as a result. In the spring of 2004, Mine Health and Safety Administration (MSHA) held a workshop to brainstorm ideas to decrease the number of injuries associated with continuous miners. One of the main areas of discussion at the workshop was “trailing cable-handling injuries.” The method of handling the power cables over the years has changed very little while the technology and uses of continuous miners has advanced dramatically. This paper will discuss the main ideas brainstormed at the MSHA continuous miner (CM) trailing cable handling workshop and the history and root causes of cable-handling injuries, as well as proposed ideas developed at the National Institute for Occupational Safety and Health (NIOSH) to alleviate some of the cable handling issues.

Jan 1, 2006

By H. Maleki, G. Tetreault

This study was initiated by the US Bureau of Land Management (BLM) to develop guidelines for determining the maximum economic recovery of resources in coal mines. The work was in response to a requirement in the Mineral Leasing Act of 1920 and Federal regulations. The intent was to address the economic rainability of small, irregular reserves in existing longwall mines. In particular, there was a need to determine if room- and-pillar mining using a continuous miner (CM) was economically sound or whether unconventional (short or odd-shaped) longwalls could be used to recover small coal reserves economically. Small reserves, called "widgets " are left in longwall mines on one side of the mains near outcrops and adverse geological conditions or near any other location where reserve geometry does not lend itself to mining with a rectangular longwall panel. The work included the analysis of the geologic, geotechnical and economic factors that influence the recovery of small coal reserves; the analysis of historic changes in supply, demand and coal prices; the development of typical cost models for room-and-pillar and longwall mines; and the development of a practical methodology for determining maximum economic recovery. The methodology included an evaluation of the ratio of coal mined during longwall mining to that mined for development (LDR), as well as costs of maintaining coal quality depending on market conditions. The LDR is a good indicator of mine efficiency and overall coal recovery in modern longwall mines and, thus, is used to evaluate the increased costs associated with adding new development sections for extraction of small reserves. The study examines the economic feasibility of using unconventional longwalls for the recovery of medium-sized reserves, depending on site-specific geologic and geometric conditions.

Jan 1, 2002

By W. Baguley, L. P. H. Greenhalgh, R. P. Riley

The traditional impeller system for aeration and suspension of slurries, e.g. in bacterial oxidation plants, is the vertical flat blade turbine (VFBT) . This type of impeller is energy-intensive, which results in a heavy-duty design of shaft, gearbox and drive. The Mixtec BX04 agitator development programme is designed to evaluate the use of the new generation of hydrofoil impellers which consume less power and thus have potential for capital and operating cost savings as well as being possibly less damaging to the bacteria. The early tests on pyrite oxidation in a 300 litre laboratory pilot tank using the Thiobacillus ferro oxidans bacteria, showed that hydrofoil impellers had superior characteristics to the VFBT impeller and to air-agitated pachucas, with lower energy input. The geometry of the air sparge ring was found to be very important in optimizing the system. These early successes resulted in a prototype impeller and sparge ring beinq tested in a 9m3 tank where oxygen uptake in water, impeller cavitation at different impeller speeds and air flows were evaluated. Resulting from this work was the supply of an agitator unit to an operating bacterial oxidation plant where it has been successfully evaluated. This paper describes the development work so far carried out

Jan 1, 1992

By Clinton A. Hollingsworth

The Flotaire Flotation Cell is a simple, efficient hydraulic/pneumatic Flotation Cell that has no moving parts. It is normally used in conjunction with a surfactant (frother) in which case the combination is known as "The Flotaire System". On many ores, metallurgical efficiencies are substantially increased and operating costs reduce. For example, in floating phosphate rock, it is not unusual for BPL recovery to be increased more than 10%, the major increase being due to floating coarse phosphate, up to 14 mesh, and the difficult to float phosphate. Substantial improvements have also been made on coal, mica, vermiculite, kaolin, barite, copper, etc.

Jan 1, 1981