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By Chisholm J. M

Why go to the CIS? The vast mineral potential of the Commonwealth of Independent States (CIS) has long been recognised, but it has taken the lowering of the iron curtain to open up the region to serious mineral development consideration by the Western World. The advent of a free market economy and the emergence of the Independent States with pressing needs for foreign investment has led to a greatly improved investment climate. Coupled with the desire for some of the more entrepreneurial resources companies to head the wave of investment to the region, this sequence of events has promised a great deal, but delivered only modest progress to-date. Potential gold project development has provided the major focus, for three reasons: the region is highly prospective for gold, gold projects tend to have a relatively lower start-up capital cost compared to base metal and fossil fuel projects and finally bullion or refined gold is more readily transportable and easier to sell.

Jan 1, 1996

By Shouci Lu, Sun. Keji

Most phosphate ores in China are characterized by fine dissemination of the intergrown minerals and high content of carbonates. Therefore, in order to recover phosphorus minerals by flotation, some technological problems must be solved, such as fine particle flotation and separation of phosphate from carbonates. For effective flotation of finely ground phosphate ores and selective separation of phosphorus minerals from carbonates, S-series and L339 modifiers have been developed. A series of combined collectors with improved collector ability and selectivity have been developed and applied in several flotation plants in China. In this paper, CCLS, a combined collector for phosphates and PA-31 and a collector for reverse flotation of carbonates, are described. It has been found that some surfactants added with fatty acids function well in flotation at lower temperature, hence heating pulp in winter may be excluded. It is important for energy savings. The synergy mechanism of these additives in fatty acid flotation is discussed in this paper.

Jan 1, 1999

By J. M. D. Wilson

An analytical program using a combination of SEM-based image analysis techniques is developed for automated modal analysis of ores containing silicate and other gangue minerals. Previous knowledge, gathered by means of either optical microscopy, X-ray diffraction, SEM, or electron microprobe analysis is used to establish discrimination criteria in the image analysis program. The program initially discriminates minerals on the basis of their relative grey values in a backscattered electron image. For those minerals which have overlapping grey levels the minerals are identified by the program using energy dispersive X-ray spectrometry with X-ray counting for twelve or more elements. This technique is useful to quantify ores in which the gangue minerals are numerous. Two cases of application are presented.

Jan 1, 1999

By Y. L. Su

This paper describes a case study where solutions were sought to the truck queuing that occurred at a central processing plant. Ore from three production shafts at Falconbridge Limited's Sudbury Opera¬tions is hauled by three trucking contractors to Strathcona Mill. On return trips, the classified mill tailing is carried back to the mines for backfilling. The ore feeder at the mill handles three times the tonnage designed for and the situation is not expected to improve. Excessive truck queuing and consequent mine production interruptions are therefore of great concern. During the study, stochastic models were formulated and programmed for the IBM/AT personal computer. Basic information sought from the models were truck waiting time and ore production interruptions. The existing system was tested, not only to verify the validity of the models, but also to understand the causes of the problem. Several alternatives were simulated and a simple solution selected for implementation.

Jan 1, 1986

By Song Xiaotian

Studies have been carried out to optimize the VCR's mining sys- tem on the basis of synthetic analysis at Fankou Pb-Zn mine in Southern China. The synthetic e- valuation method is proposed for selection of mining alternatives and stope dimension optimization techniques. Theoretic calculation and computer optimization of the fragmentation of rock blasted by multispherical explosive charges are discussed. The mathematical and optimal fragmentation models are built. The optimum model is built for the main mining operations such as drilling, blasting and haulage. Lt can be used to evaluate VCR?s mining projects, select mining parameters and provide design fundations. From the point of view of system research on the geomechanical process, stoping technological process and benefit, the complex method of optimization is proposed for VCR's mining. Using computer simulation, based on this model, the optimal parameters are established and analysed. An effective approach is provided for research on the mining method optimization and getting better economical benefits from the application and improvement of VCR's method.

Jan 1, 1986

By Christopher Haycocks

Successful ground control is an essential part of all viable underground mining operations. To a large extent ground conditions influence the choice of mining methods, percentage and cost of extraction, and often the degree of safety that can be achieved. Utilizing the computer for ground-control planning offers great potential under many diverse conditions as not only are computations facilitated, but also details of the often complex geologic and structural framework of the mine can be readily stored and retrieved. Two basic approaches have been developed for applying the computer in solving ground-control problems. The first uses an analytical method, such as the finite element technique, for solving a specific problem. The second is more general and involves storage of geologic data and application of general design equations. The latter has found wide application in stratified deposits. It is the purpose of this chapter to describe both approaches as they are used for improving the ground-control aspects of mine planning.

Jan 1, 1979

By L. Y. Zhang

The current status of metal hydride alloys for NiMH batteries was systematically reviewed. Extensive application-oriented research and development has successfully made the NiMH battery an important part, with growing potential, among rechargeable batteries. The rare earth based metal hydrides (AB5) have been considered the best alloy material for use in the negative electrode in NiMH batteries. However, being in demand for high performance electronic markets, the still young NiMH industry is facing serious technical challenges in developing better products. Among all the efforts to respond to the challenges, advanced AF3, alloys are in great demand: the capacity enhancement race requires new or improved alloys possessing higher volumetric capacity; price competition mandates MH materials with low cost; high performance under severe service environments calls for alloys with high corrosion resistance when subjected to electrochemical cycling; and finally, high power service requires the negative electrode to deliver current at high rates.

Jan 1, 1997

By Charlene Gokhale

Geopolymerisation has emerged during the last few years as an industrial and ecological approach to construction and waste management. By utilizing waste materials and their reactive properties, it is now possible to create geopolymers systems that not only mechanically durable enough to be used as construction materials but are also potential stable immobilisation systems for toxic waste. Previous studies by Van Jaarsveld et al. (1997) and Van Jaarsveld et al. (1998) have reported on the numerous applications of geopolymers in the immobilisation of toxic metals. Research into the possible utilisation of geopolymers as an encapsulation media for organic waste has however been rare. This paper therefore provides an insight into the possible utilisation of geopolymers as a binder for hazardous organic materials.

Jan 1, 2003

By Ronald S. Conti

Fire is a major concern for those who work in underground mines. A mine fire can occur at anytime and often results in a partial or total evacuation of mine personnel and could result in the loss of lives. Therefore, having a workforce that is well trained to prevent, detect, and fight a fire is important. This paper focuses on responders’ preparedness for fire. Responders in this context are considered the entire workforce and are categorized as first, second, and sustained responders and evacuating miners. Quality training enhances ones awareness of mine fire hazards and promotes self-confidence in combating fires and responding to emergencies. Early warning systems and other escapeway aids such as a through-the-earth signaling and communication system, lasers and strobe lights are also addressed. The technological advancements that have been made can improve the state-of-preparedness for responders to underground emergencies and increase the chances of survival for escaping personnel.

By Thompson IR, Solomons SS

Underground mining with the cut and fill method has been declining during the past decade or so, being replaced mostly by sublevel open stoping methods. During 1983 the Australian Mineral Industries Research Association Ltd. (AMIRA) commissioned a review of the method, with the aim of compiling the state-of-the-art, indicating future trends and recommending topics for research that would be needed to support this future mining. Mines using the cut and fill method in Australia and three other countries were visited to compile current practices and expected developments.Cut and fill is mostly used where geological and ground conditions are unsuitable for open or caving methods. These range from narrow, irregular orebodies to wide, massive orebodies where pillars are retained in ore. There is significant potential for improvement and further development of the method. It may then be used in a broader range of conditions and for orebodies that may not otherwise be viable to mine.

Jan 1, 1985

In November, 1967, a four strand curved mould continuous casting machine coupled with a 50 ton basic oxygen furnace began producing billets for the rod mill and new merchant mill at the Newcastle Steelworks. To date over 500,000 tons of carbon and alloy steels have been cast at the rate of 20,000 tons per month, the major part for the wire industry. Many alterations have been made to the plant to simplify the process, improve quality and increase production. Casting parameters have been developed for each different type of steel. The quality of the final product has been influenced most by casting temperature, secondary cooling and casting speed. All these factors have been controlled and good results are reproduced. More exacting requirements of liquid steel quality have brought about the use of higher lime/silica ratio slags during steelmaking to control phosphorus revers- ions and standard ladle additions of manganese suicide and ferro aluminium for more effective deoxidation.

Jan 1, 1972

By Michael E. Stickney

"Soft technology" computers and computer programs-brings to mind a room full of machines, tape drives, disks, plotters, and printers spitting out financial reports. Computers now have a much broader scope of applications because of reductions in equipment size and cost. For example, people now interact directly with computers to control events. Such computers and associated equipment-called interactive control systems-are often small, relatively inexpensive, and can be designed to increase productivity at mining operations. This is accomplished by improving communications between individuals; giving employees the information needed to make decisions in real time, as events are happening; and giving individuals the background needed to perform more effectively. This paper will describe a procedure for determining the return on investment for interactive control systems, and describe four such systems. The analysis process is general in nature and can be applied to any type of mining operation or production process.

Jan 4, 1981

By H. N. Maleki

The results of five years of geotechnical investigations are presented to develop productive and stable longwall layouts for the Foidel Creek Mine. The program was initiated during the pre-mining stage, and has continuously provided the data required for mine design. From several stress determinations at the mine, the relationship between geologic structure and the stress field/depth was established. The results were used for orienting the entries for improved stability. Cave conditions and load transfer to panel boundaries were evaluated from closely monitored full extraction mining and computer analysis. Back-analyses of ground movements, as compared with the actual measurements, indicated that cave conditions were favorable in spite of the presence of competent, thick-bedded sandstones in the mine roof. Gate pillar design using a yield-rigid concept was developed through computer analyses and underground instrumentation, resulting in 35 and 75 ft wide pillars. The influence of a slickensided bedding plane at the roof contact on pillar yield zones, core confinement, and pillar behavior was evaluated.

Jan 1, 1988

By M. Abdellatif

Successful demonstration of The Mintek Thermal Magnesium Process (MTMP) was achieved in November 2004 at the pilot-scale, About 30 tons of magnesium producing recipe was smelted in the DC arc furnace over a continuous operation of 8-days, Twenty-two furnace batching-tapping operations were carried out at a feed rate of 525kg/h and a smelting temperature of 1600-1700°C, The MgO content in the produced slag was as low as 6,7%, and averaged 9,2% MgO, resulting in an overall magnesium extraction of 77%, which reached 87% during good operating periods, Magnesium vapour was extracted at a rate of 70-85kg/h and was delivered to the condenser that was operated at 680-720°C, The magnesium was captured in the condenser crucible in a liquid state, allowing its prompt tapping, More than 3500kg of crude metal were produced over 15 on-line metal tapping operations, On average, a condensation efficiency of 85% was achieved during the entire testwork, which peaked at 87% during steady operations, The quality of the crude metal was similar to, if not better than, that of the Magnetherm's crude magnesium, A pre-feasibility study has indicated that the MTMP has the potential for lower capital and operating costs as compared to the electrolytic process, and therefore Mintek and its consortium partners are exploring opportunities for a commercial production facility.

Jan 1, 2006

By M. E. Gershon

Conventional methods of drill hole site selection are reviewed briefly. Two approaches using geostatistics are then discussed, both of which have been shown to yield improved results. Finally, a branch and bound algorithm is described which will select the best locations for drilling from a user specified number of possible drill sites. Two options are discussed. First, the user can specify a maximum drilling investment or a maximum number of drill holes and the program will select the locations yielding the minimum estimation variance. This amounts to getting the most for a given investment. Alternatively, a maximum tolerable estimation variance can be specified and the program will select the number and location of the drill holes to obtain the desired information at a minimum cost. Another benefit of the approach is the quantification of the tradeoffs between investment and information obtained.

Jan 1, 1985

By Just GD, Gillies ADS

There is an increasing need for reliable and comparable coal resource data and it is necessary to standardize the traditional classification procedures by quantifying the three basic evaluation criteria of economic feasibility, geologic assurance and recovery. For well documented deposits, geostatistical methods can consider- ably improve classification quality. A geostatistically based algorithm for classifying coal resources within the current Queensland and New South Wales codes has been developed. Application of the method in classifying resources from a number of seams exhibiting different structural characteristics is assessed. The method is found to give classification results which closely reflect the error associated with an estimate of resource quantities based on current sampling densi- ties. It requires a careful geostatistical analysis with emphasis on geological awareness. Resource category restrictions must be arbi- trarily assigned and remain constant for all deposits being compared. Engineering judgement is needed and interpretation may be required with isolated and peripheral blocks.

Jan 1, 1987

By H W. Wu, T Harvey

An overview is given of two new developments in mine atmospheric monitoring. A new personal dust monitor (PDM) that gives real-time respirable dust readings is discussed. The unit is mounted within the minerÆs cap lamp battery and internally measures the true particle mass of dust collected on its filter. Samples are available for later mineralogical analysis and results do not exhibit the same sensitivity to water spray as optically-based measurement approaches. The technique achieves microgram-level mass resolution even in the hostile mine environment and reports dust loading data on a continuous basis. The monitor has been evaluated under an Australian Coal Association Research Program (ACARP) grant and is being adopted for statutory mine respirable dust determinations in the United States (US). The monitor has particular application for determining location of high dust sources. It can evaluate the efficiency of engineering means of suppression and other approaches to reducing dust levels. It has been recognised that the PDMÆs unique measurement approach has application to allow real-time atmospheric diesel particulate matter (DPM) monitoring. The industry has no real-time atmospheric DPM monitor at present. Recent surveys in New South Wales and Queensland show significant numbers of miners continue to face full shift DPM exposures in excess of internationally accepted levels. Real-time DPM monitoring will allow the industry to pinpoint high exposure zones where a number of trucks and other vehicles work in areas of poor ventilation. Knowledge of high DPM concentration zones allows efficient modification of work practices to reduce underground minersÆ exposure. Approaches to uses of the DPM form of the monitor and the design of tag boards are discussed. Some outcomes from mine tests with both these new instruments are given.

Jan 1, 2008

By Charles C. Boley

Using bench-and pilot-scale coking facilities, the Bureau of Mines produced experimental coke from blends of char with Sunnyside coal (high-volatile A bituminous) from Carbon County, Utah. At bench scale, additions of char made from lignite improved resultant cokes when concentrations of up to 60 pct were used in the blends. At pilot scale (500-pound movable-wall oven), four chars made by entrained-bed carbonization techniques from the parent Sunnyside coal and from a North Dakota lignite were used in two-component blends with the Sunnsyide coal. Chars from Sunnyside coal had volatile matter contents of 5.8, 9.8, and 16.0 pct, moisture-free basis; the char from the lignite had 16.6 pct. In twenty-five 500-pound tests, improvement in coke quality was observed from all blends at char concentrations to 17.5 pct. The best coke, produced from a concentration of 12.5 to 15 pct of S.8-pct volatile char, exhibited physical properties approaching those of an industrial coke produced from Sunnyside coal blended with three higher rank blending coals. Studies were also made of the effects on coke quality of char source, of particle size, of comparative use of char and of a blending coal, and of prolonged coal storage.

Jan 1, 1973

By Andrew T. McBride, Malcolm S. Powell, Indresan Govender

"Current empirical Semi Autogneous Grinding (SAG) mill models contain assumptions concerning the amount of energy available for particle breakage, how this energy is distributed in the mill media and the rate at which the energy is transferred. Despite these assumptions the JK SAG model is highly functional with a proven track record. DEM provides a numerical framework to greatly improve on these assumptions that were necessary due to a lack of available input data.This paper identifies key outputs of the Discrete Element Method (DEM), such as energy spectra and impact probability distribution. It describes how they can be incorporated into current mill models utilising practical rock breakage data. The rate at which energy is transferred is shown to be dependent on particle position and mill rotational speed and not once per cycle as previously assumed. Based upon this an improved energy transfer methodology is presented. The fundamental outputs of the DEM are validated against experimental three-dimensional particle tracking data, so as to establish whether the DEM produces correct energy transfer predictions on the inter-particle level, which is crucial to this work. • Effective Experimental ValidationAn automated 3D tracking technique is employed to study the motion of plastic particles deep within the charge of a 142mm diameter experimental mill. A Biplanar Angioscope is used to film the mill with X-rays in two planes simultaneously at 50 frames/s, with a shutter speed of 1/3000s. A marked ball within the charge is tracked for over 2 minutes and the resulting digital images processed by a fully automated imaging technique, which locates the 3D coordinates of the particles to within 0.2mm. With over 250 circulations, this provides statistically rigorous and accurate data for verification in the numerical modelling of mills.A series of validation techniques have been developed to compare the experimental trajectory data with the outputs of both 2D and 3D DEM simulations. The techniques describe the shape of the charge and the particle motion within mill, allowing objective comparisons to be made of key features of the charge, such as the equilibrium surface and the centre-of-circulation."

Jan 1, 2003

By Curtis G. Kremer

"New explosives initiation systems continue to be developed as new technologies make advancements possible. Due to recent initiator developments, explosives users now have the most reliable, accurate, safest and easy to use systems ever offered. Three initiation systems recentlyintroduced which offer significant improvement over standard electric and nonelectric initiation systems include Magnadet, EXEL high-strength shock tube, and Redundant two-Dath surface delay systems. These three systems will be discussed zn cecail with rmpiasis on their functioning, safety characteristics, ani specific application areas."

Jan 1, 1991