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The application of Kirchoff's laws to two adjoining mine ventilation network meshes containing fans results in the construction of two general quadratic equations. These equations may be solved to give the resultant airflows and hence fan duties within the system for given network parameters and fan characteristics. This technique has a wide application for calculating the duties of fans in various combinations within a mine ventilation system. Recent difficulties in economically maintaining environ- mentally safe conditions in underground working areas distant from main ventilation fans has led to increasing interest in the use of controlled partial recirculation of ventilation. This paper develops a recirculation model which can be solved directly using mathematical techniques obviating the need for iterative techniques such as the Hardy-Cross method. The advantage of a direct mathematical analysis is that mathematical algorithms may be constructed to completely describe the ventilation system under a wide range of operating conditions. This technique is applied to controlled partial recirculation ventilation systems to demonstrate its advantages for mine ventilation planning.

Jan 1, 1989

By J. E. Hoffman, T. J. Keefe, Michael E. Stout, O&apos

M.A. Industries, Inc. has developed and is now offering on a commercially available basis, complete systems to recover and recycle lead from spent SLI batteries. The system begins with the breaking and separation of the component parts of the batteries and subsequent treatment of the effluent water produced by this operation. The recyclable materials recovered from this process are metallic lead, lead paste and polypropylene. The lead paste is introduced into a process to convert it from a lead sulfate to a lead carbonate. The process also regenerates the salt solutions into reusable carbonate. The lead carbonate is then leached into an acid bath where it is later recovered by a proprietary electrolytic process. The metallic lead is recovered in a short rotary furnace producing metal for further refining and alloying. The polypropylene is further washed and then introduced to a reclaim extruder along with the proper modifiers and additives. The resulting resin can then be sold on the open market to injection molding processors. This complete system greatly reduces the amount of waste to be disposed of and completely complies with all applicable EPA guidelines.

Jan 1, 1993

By Norbert Patzelt, Johann Knecht, Wolfgang Baum

High pressure roll grinding (HPGR) is a mature but still expanding comminution technology. In the metals mining industry, HPGR is slowly gaining acceptance as a cost-efficient, high-throughput alternative for plant optimization. The increasing need to treat ores with progressively lower grades, complex mineralogies, refractory metal occurrence and variable rock types requires an energy-efficient comminution technology that reduces metallurgical problems inherent in conventional crushing and grinding, while stabilizing leach and flotation circuits and increasing metals extraction. This paper will summarize our latest HPGR pilot test results for gold and copper projects in the United States and South America and their confirmation through the first HPGR operation in copper mining. This paper will also stress the use of the high pressure grinding roll as a metallurgical tool. The application of HPGR for the treatment of heap leach SX-EW ores, semi-refractory gold ores, waste rock material and concentrator feeds will be illustrated.

Jan 1, 1998

By A. S. Ibrado, D. W. Fuerstenau

The adsorption of the cyano complexes of Ag(I). Cu(l), Hg(II), Cd(II), and Zn(II) on activated carbon was investigated as a function of pH and correlated with the speciation diagram for each metal. The results show marked changes in uptake with pH, closely resembling the predominance profiles of their neutral and singly charged cyano complexes. Multicharged negative complexes are repelledby the negatively charged carbon surface. The sensitivity of activated carbon to the charge of the adsorbing species indicates that silver adsorbs as an anion, not chemically bound to the coadsorbing counterions. For the same reason, activated carbon is selective to metals that preferentially form neutral and singly charged cyano complexes, namely gold and silver.

Jan 1, 1990

By Barbara C. Williams

U.S. Bureau of Mines researchers conducted field studies at an abandoned copper-gold mine tailings impoundment. Pore water quality was analyzed in the vadose and saturated zones. Three statistical procedures were employed to summarize the variability within and between the two zones. The results indicated that linear combinations of those variables reflecting sulfide oxidation and aluminum-silicate weathering best summarized the variability in each zone, and that the zones were most different on the basis of sulfide oxidation variables. The geochemical computer code WATEQ4F was used to assess the solubility status (saturation index) of minerals. Saturation indices of sulfide oxidation and aluminum-silicate weathering minerals were different in the two zones. It was demonstrated that the statistical analyses produced similar and complementary results to the geochemical code.

Jan 1, 1992

By L. Henry Smith, David C. Arthur

The Williams Mine is Canada's largest gold producer, with annual production of 14,000 Kg (450,000 ounces) from 2,300,000 tonnes of ore. Highly mechanized and automated underground mining practices are employed in order to achieve and maintain high levels of productivity and minimize costs. The Mine Ventilation System is modified to include a new Vent Raise and Variable Pitch Vane-Axial Fan. This addition allows several fan installations underground to be decommissioned. A substantial net savings in installed horse power is achieved. Heating costs associated with underground ventilation air are a significant portion of mine operating costs. Air heating costs are substantially reduced by recovering heat from upcast exhaust air, mine water and compressor cooling circuits. This waste heat is used to supplement propane fired air heating systems for underground ventilation air. An additional benefit is the availability of a heat sink for summer cooling of the compressors. System design, energy savings data and payback calculations are presented.

Jan 1, 1997

By D. D. Runnells, D. C. Keith, G. A. Doyle, J. Tilk

Until the suspension of conventional operations in 1996, the White Pine Mine was the second-largest active underground copper mine in the United States, underlying an area of approximately 30 km2 (13 sq. miles) in the Upper Peninsula of Michigan. The mine operator intends to initiate in-stope solution copper mining by circulating a solution (lixiviant) of mine water, sulfuric acid and ferric iron through rubblized ore. As planned, the solution would be retired in the mined-out stopes following completion of the solution-mining activities. Investigations into the fate of the retired solution indicated that the solution, through time, would change from an acidic, metal-rich solution to a near-neutral, reducing solution containing much lower concentrations of metals. Investigations included reaction-path modeling (EQ3/6) and laboratory and in-mine tests. The combination of neutralization and reduction will result in precipitation of most metals, primarily as metallic sulfates, chlorides and sulfides.

Jan 1, 1998

By R. K. Mehta, G. T. Adel

A review of the literature reveals that methods for simulating the coupled behavior of size reduction and liberation are limited to binary mineral systems containing one composite particle class. The aim of this paper is to describe the development of a mathematical model to simulate such behavior for binary and ternary systems containing multiple classes of composite particles. A modified Levenberg-Marquardt algorithm and a finite difference Jacobian are used in conjunction with the developed model and a set of constrained equations to estimate all kinetic parameters. This estimation scheme is validated far a binary ore (sphalerite-dolomite) with five composite particle classes using experimental data.

Jan 1, 1991

By T. H. Combs, G. T. Lineberry

Increased productivity in the US underground coal industry has taxed pre-existing conveyor belt haulage systems. The usual remedies are costly and can disrupt production. A reduction in the belt feeder discharge rate on shuttle car sections results in more uniform loading and reduces spillage vulnerability. An investigation was made to determine the effect, if any, on shuttle car discharge time arising from lower feeder discharge rates. A five-section, underground mine is modeled, and belt spillage is introduced. The sectional feeder discharge rate is progressively lowered until spillage is precluded. At each level, the simulated spillage is measured and compared to the loss in face production. Methods for predicting the loss in face production from lower feeder discharge rates were investigated.

Jan 1, 1995

By D. Tao, B. K. Parekh

Fine coal particles are difficult to separate effectively from liquids or other solids. Ultrasonic energy may be used to enhance the efficiency of the conventional fine-particle separation processes widely used in the coal and mineral industries. Flotation, settling and dewatering tests were conducted using several fine coal samples to study the effects of ultrasonic treatment on these processes. Process variables such as particle size, ultrasonic treatment time and solids concentration were investigated for their impacts on ultrasonic treatment effectiveness. The results obtained from this study showed that ultrasonic treatment is an effective approach for enhancing solid/solid separation in flotation and solid/liquid separation in sedimentation and dewatering of fine coal. SEM microphotographs demonstrate that ultrasonics cleaned particle surfaces, which is, in part, responsible for the observed improvement in fine coal separation processes.

Jan 1, 2000

By M. Prasad, A. K. Majumder, T. C. Rao

The depletion of high-grade phosphate ores is bringing about a search for a suitable, economically viable technique that con process the abundant low-grade phosphate reserves. About 75% to 80% of the world's low-grade phosphate reserves are associated with carbonate gangue that is not amenable to treatment by the simple techniques of physical separation. The processing of sedimentary dolomitic/calcareousphosphate ore has numerous problems, including similar surface properties of the carbonate and phosphate. Two-stage reverse anionic flotation of carbonates (dolomite/calcite) has appeared to be a promising separation technique ,for the removal of carbonates from sedimentary rock phosphate. In reverse fatty-acid anionic flotation, the depression of phosphate mineral with orthophosphoric acid produces satisfactory results for calcareous as well as dolomitic phosphate ores from several locations of sedimentary origin.

Jan 1, 2000

By Dilip K. Sinha

In the paper some interesting cases of applications of Operations Research and Computer Methods as worked out by the author and accepted by the management of some of the newly formed Indian mining organisation for implementation are highlighted. The main emphasis on the application cases was to use simple techniques and methods which yield the result in shorter time period, The case problems mainly deals with the production system optimisation in unit mines, areas/divisions and at the corporate levels. Also the management decisions regarding reorganisation of transport and distribution system of material and mineral are attempted to be optimised. Further, the case of management system development with computer aided decision making worked out for single large Iron Ore Project captive to a steel plant is outlined. Finally, the case of a large mining company having decentralised units and divisions geographically dispersed throughout the country, computerised management decision-information system designed on the basis of inputs and outputs of decision models relevant for different levels of management in the organisation is depicted.

Jan 1, 1986

By K. N. Han, M. C. Fuerstenau, T. B. Onlin

A mathematical model describing the concentration profile of fine particles in the axial direction in liquid fluidized beds has been developed for the removal of fine particles. A forward finite differentiation technique has been used to solve a continuity equation with a source term to predict the concentration profile and, hence the recovery as a function of time. With the aid of experimental results obtained using a fluidized bed of 3-cm diam, dimensionless parameters were identified. These parameters were used to predict the concentration profile of fine particles in fluidized beds of larger sizes. Four different sizes of fluidized beds, namely, 1.3, 3.0, 4.0, and 7.5 cm in diam, were used in this investigation. The amounts of bed particles used included 4, 8, 16, 24, 59, and 120 g, and the size of bed particles were 48x100, 100x150 and 150x200 mesh.

Jan 1, 1987

By N. D. Cristescu

An analysis of the interaction between a creeping rock and a yieldable lining is presented. The following cases are considered: an elastic lining, a lining made of circular shaft rings that may slide at their joints, a lining made of circular reinforced concrete panels with wooden compressible strips inserted between the longitudinal joints and a yieldable support that has a compressible broken-rock stratum between the support and plane rock. By formulating a mathematical model for the rock-lining interaction, one can optimize the sequence of excavation-lining application. To keep costs to a minimum, one can also choose the most appropriate lining for the corresponding rheological properties of the rock.

Jan 1, 1997

Political events during the past decade have caused businesses throughout the world to think globally. Countries once closed to free market enterprises are now open and seeking out foreign investment to help improve the well being of their populations. The mining industry has always been a global one. Today, though, the industry has become even more global. The driving forces behind this include the opening up of higher grade, lower cost mineral deposits in undeveloped and developing nations. In addition, permitting delays in the United States, coupled with stricter environmental guidelines and a general anti-mining attitude, have forced the mining industry to look outside US borders. The Mineral Economics and Management Society (MEMS) took as the theme of its seventh annual professional program "Economic Globalization of the Mining Industry." About 100 people attended the conference held in Arlington, VA in late March. Speakers included members of the investment community, academia, government and the mining industry.

Jan 1, 1998

By M. C. Roberts

To assess the future markets for a mineral from a producing district, the following three aspects must be considered: the future growth of the markets, the competitiveness of the district in terms of production costs and reserve adequacy, and the competition from alternative sources of supply. This paper focuses on the first issue by developing a method for predicting the demand for phosphate from trends in the major market for phosphate products, the fertilizer and agricultural market. The paper shows how broad changes in this end-use market for phosphate has evolved over time. These trends are then projected into the future to make an assessment of future phosphate requirements.

Jan 1, 2000

By Andrew F. McKown, Lewis L. Oriard

Advances in explosives engineering are moving forward in several different aspects. These include improvements and new development in explosives products, the application of these products to blasting technologies, and the study of the peripheral effects of the use of explosives, such as ground vibrations and airblast. Topics of special interest in the last several years include new explosives and detonators, cap timing, explosive casting, high-speed photography, perimeter and slope control, air decking and mathematical modeling of blasting processes.

Jan 1, 1988

By Debra W. Struhsacker

Waste characterization plays an essential role in proactive project permitting, design, reclamation, and remediation strategies. Traditional TCLP tests and chemical analyses used in many studies do not provide adequate data to predict the long-term geochemical behavior of the mineralized system. Mineralogic and geologic data are needed to assess the homogeneity of the system, the potential for acid generation or metals leachability, and the amenability of the material to traditional and unconventional closure and reclamation measures. The characterization efforts done from the evaluation stages through final closure can aid in better cost evaluations, more representative sampling, more effective neutralization and waste containment measures, and optimized reclamation designs.

Jan 1, 1995

By Yoginder P. Chugh, K. V. K. Prasad, R. Missavage

This paper presents results of field monitoring and finite element studies to analyze and improve a room-and-pillar retreat mining system. Fie1 d instrumentation was utilized to monitor pi11ar load changes, roof to floor convergence and differential roof strata movement as retreat mining progressed and to determine in-situ horizontal stresses. A two-dimensional finite element model depicting strata behavior at this mine was developed and used to analyze existing and alternate improved mining geometries. The results showed excellent correlation between fie1 d observed and model predicted behavior. Some of the recommended changes in mining geometry based on the study were incorporated in the mining system.

Jan 1, 1986

By Corale L. Brierley

The depressed economic condition resulting from normal cyclic behavior, a more fundamental structural alteration, or both, is a mandate for change within the mining industry. Although several strategies for change have been proposed, the option of applying high technology processes to this smokestack industry offers the greatest opportunity for regaining global competitiveness and a new vitality. Research and development to secure new technologies require a corporate commitment for substantive change, a tech¬nologically enlightened management, a well¬funded and stable science and engineering effort, and a dedicated and motivated technical team--features in short supply in the mining industry today. However, an alternative to in-house development of frontier technologies is available to this beleagured industry through entrepreneurial, high-tech companies. These entities, with their dedicated focus toward product development, motivated and streamlined teams, high productivity and efficiency, and low costs offer a unique opportunity for large corporations to obtain high-tech products and services. These commodities are available through traditional commercial channels and an array of creative business arrangements. The latter offers notable benefits to large companies including windows on frontier technologies and mitigation of risk. Likewise, entrepreneurial companies profit through manufacturing and marketing relationships and an expanded financial base.

Jan 1, 1985