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By Gordon I. McPhail, John D. Nelson

Tailings management represents a major portion of the cost associated with extraction of gold. For each gram of gold extracted, 150 to 200 kg of waste material is produced. Because of environmental concerns and unwillingness of society to accept environmental damage caused by poor waste management practices it has become essential to follow responsible and safe practices in tailings management. This paper presents general aspects of tailings management and discusses different techniques utilized. Characteristics of tailings and the effects that these have on stability and environmental aspects are discussed. The paper also discusses the effect of mine back-filling practices on the surface disposal of the remaining tailings fraction.

Jan 1, 1987

By John Matthews

During 1982 and 1983, it became increasingly clear that North River No. 1 Mine would have to buy a set of replacement longwall shields. Despite extensive efforts to make improvements, the shields that were in place at that time were incapable of holding the roof. North River Energy had limited experience in specifying and acquiring longwall roof supports, but a great deal of experience with our conditions and needs. We there- fore compiled a shield evaluation method that uniquely responded to our situation. The resulting system emphasized teamwork among operating, maintenance and engineering personnel. The charge from management was threefold: select shields to support maximum expected loads, optimize face operations, and pay attention to detail. Final selection was made objectively, based on all available information. We chose a 5516 KN (620 tons) support with a minimum yield load density of 760 KN/m2 (7.9 tons/ft2). This paper reviews our process of specification, design, prototype testing, and fabrication, and offers some relevant suggestions.

Jan 1, 1986

By Winthrop F. Watts, Robert W. Waytulonis

During the 1980's. the Mine Safety and Health Administration (MSHA) proposed new regulations for the use of diesel equipment in underground coal mines, and the National Institute for Occupational Safety and Health (NIOSH) recommended that whole diesel exhaust be regarded as "a potential occupational carcinogen", and that reductions in exposure to exhaust pollutants would reduce excess risk. During the same time, the Bureau of Mines tested new emission control technology to minimize diesel emissions. The objectives of this paper are to discuss the major issues regarding diesel exhaust emissions. especially diesel particulate matter (DPM) , and to highlight emission controls that will be available. DPM is a potential health threat because it is respirable in size and is composed of nonvolatile carbon with adsorbed or condensed compounds. These compounds include potentially mutagenic or carcinogenic hydrocarbons such as polynuclear aromatic hydrocarbons and sulfates. DPM contributes to the degradation of air quality in mines with typical mean concentrations ranging from 0.2 to 1.0 mg/m3. In addition to adequate ventilation, control of DPM can be achieved by implemention of improved work practices, regularly scheduled engine maintenance, and emission controls.

Jan 1, 1991

By R Willis, D Cooke, G J. Davidson

Mine-groundwater interaction at the Pasminco Rosebery Mine (PRM), western Tasmania, deserves special attention due to the unique climate and mining environment present. High rainfall and low evapotranspiration result in an excess of water, an uncommon problem at Australian sulfide bearing mines. Research is being undertaken to delineate current subsurface fluid flows and predict future fluid flows in order to improve management after mine closure. Acid mine drainage generation is well developed in abandoned mines throughout the area. If acid mine drainage is not controlled after mine closure, significant environmental degradation could occur in the receiving waters of the Pieman River system. The study area encompasses the heavily forested Mount Black, and underlying PRM workings. Groundwater flows beneath Mount Black through a crystalline fractured rock aquifer with faults and underground mine workings observed to act as the major hydraulic conduits. Recharge is controlled by local precipitation, and the ultimate discharge is thought to be the Pieman River system, which forms the topographic low in the area. Slug tests have been used in conjunction with the mineÆs extensive geotechnical database to spatially evaluate variation in hydraulic conductivity. In fractured rock terrain associated with mining, rock quality designation data can be a useful tool in delineating areas of similar hydraulic conductivity when combined with conventional hydrogeological methods. A GIS, mine planning software, an environmental and a geological database are linked to form the input for groundwater modelling.

Jan 1, 2003

By Butters S. E, Deslandes J. V

The selection of loading and haulage equipment in a proposed or oper- ating mine is vital in ensuring the cost effective achievement of produc- tion targets. To assist in the evaluation of different haulage systems, a truck haulage simulation model has been developed at BHP Melbourne Research Laboratories. The operation of the model is described and exam- ples of an actual application at Mt. Whaleback Mine is presented.

Jan 1, 1989

By Sun Y. L, Jiang J. J, Lu S. L

A distinguishing feature of tunnels in squeezing rocks is that a large deformation of the surrounding rocks takes place slowly and gradually, often called squeezing phenomenon. It is different from the rocksbursting phenomenon during which the deformation of tunnels occurs instantaneously when the resulting stresses exceed the strength of the surrounding rocks. The squeezing phenomenon has received great attention in the field of rock mechanics and tunnelling recently. The mechanism and various factors related to the large deformation and failure of tunnels in squeezing rocks are discussed in this paper on the basis of field investigations and laboratory model tests. The relationship between the deformation of surrounding rocks and support of the tunnels in squeezing rocks is presented in the form of numerical modelling.

Jan 1, 1995

By V. W. Skema, M. W. Smith

Pennsylvania has 4,000 km (2,500 miles) of streams that do not meet water-quality standards due to acid mine drainage (AMD), making AMD the greatest cause of water pollution in the state. The problem is mainly caused by abandoned coal mines. To abate AMD, Pennsylvania is using a watershed-based approach that includes remining as a key component of a comprehensive restoration strategy. The Tangascootack Creek Water-shed was targeted for AMD restoration through remining. Geologic mapping and overburden data were analyzed using Earth Vision software to identify areas of coal reserves that could be remined to improve water quality. Incentives are offered to encourage mining in these designated areas.

Jan 1, 2002

By H. J. Winters

Position of the Porphyries in US Copper Supply The United States continues to be the largest producer and consumer of copper in the world. [Table 1] shows several production statistics for 1974, the most recent year that the non-communist world copper industry might consider a good year, and for 1976 and 1977. In 1974 an estimated 24% of the non-communist world's newly mined copper was mined in the US, and 87.89% of that was from the western porphyry coppers. In 1976 US new mine production was down to 22% of the non-communist world's newly mined copper, and the percentage of US new mine production supplied by the porphyry coppers had risen to 89-91%. In 1977 the statistics remained the same as in 1976. US porphyry copper production represented about 65% of US refined copper consumption in 1974, rose to 75% in 1976, and dropped back to 61% in 1977 as imports of foreign copper into the US began to swell. The financial situation of the porphyry copper mining industry continues to be very unhealthy. To see why; we can take a quick look at costs and prices.

Jan 1, 1982

By Miller M. J, Bauer J. C

The continuous copper drossing process operated at Port Pine since 1962 has had limited copper removal capacity as determined by a maximum tolerable Cu/S ratio in feed and the level of sulphur in blast furnace bullion. Recent process development has been to overcome these limitations to meet increased copper throughput requirements. A sulphur addition system was developed and installed in August 1987. The system has capacity to increase sulphur input by over 150%, meeting the increased copper capacity requirement and also allowing independence from the upstream process for sulphur supply. Developments in process understanding have been applied within the limitations of the existing furnace design with a 10% increase in the maximum tolerable Cu/S ratio.

Jan 1, 1989

Copper from Central Africa was well known to the Arab slave traders who depredated the country in the nineteenth century. By the 1870's slave raiding was so intense that the habits of the tribes were disrupted, and they no longer worked the copper deposits or made the crosses and bars of copper which had been their custom. In fact, the country had been greatly depopulated by the slave raiders. News of this horror was spread to the civilized world by missionaries and, in particular, by David Livingstone's writings. Whether to extend geographic knowledge, to suppress slavery or for national aggrandizement, the rush for African territory was on at the end of the nineteenth century. Cecil Rhodes at this time was established by his successes in diamonds and gold. He obtained the blessing of Lord Salisbury in 1889 to form the British South Africa Company under crown charter. His objectives were to occupy the lands north of the Zambezi for England and pay for development out of the country's mineral deposits. He planned to occupy the territory and close the gap to form an all-British route from the Cape to Cairo, one of his great dreams. With this master plan in mind he sent his agents into the field to make treaties with the tribes.

Jan 12, 1962

By Just G. D

Performance of draglines in large scale overburden stripping operations is critical to the efficiency of a major section of the Australian Coal Mining Industry. Optimisation of dragline productivity requires an understanding of a range of operating conditions and constraints. One of the least understood of these operations is the process of bucket filling and how this may vary with respect to variable operating conditions.Studies conducted at The University of Queensland over a number of years into this problem have enabled the mechanics of excavating to be assessed for different types of fragmented rock. In relation to bucket filling, factors such as fill volume, digging time and energy consumption have been found to be significant factors in optimising bucket design, bucket rigging and operational techniques.

Jan 1, 1992

By W. C. Peters

From the time of its beginning in the mid-19th century, the American barite industry has had its major development in the eastern and central states. Geologic and economic factors serve to maintain Arkansas, Missouri, and the Southern Appalachian states in the lead position. In earlier days, the major markets for barite were in paint, chemical, and glass manufacturing, and the favored deposits were those which were close to eastern industrial areas; furthermore, the eastern deposits were cheaply mined and required little or no beneficiation. In the last few decades, the use of barite as a weighting medium for muds in rotary oil well drilling has caused a great expansion in the industry, but the marketing picture is still centered outside of the western states-now on the Gulf Coast area where high pressures are common in oil wells. Low cost imported barite, readily available on the East Coast and Gulf Coast, has always been a major marketing factor in the industry. The major barite producing state is Arkansas, with the industry centering about the Magnet Cove area. Missouri ranks second, with production mainly from residual deposits. Several Southestern states are actively producing from residual deposits.

Jan 9, 1958

By de Brodtkorb MK

Late Cenozoic ore deposits "Precious and base metal-rich" and " Sn-Ag-polymetallic"of Northern Puna are associated either with Middle Miocene dacitic volcanic-dome complexes or with Upper Miocene dacitic-andesitic volcanic centers. Ore mineralogies and their related volcanism are discussed. A strong link is observed between the Cenozoic Metallogenetic Province of Northern Puna and the Southern Bolivia Tin and Polymetallic provinces.

Jan 1, 1995

By Norman A. Jull, A. L. Mular

Fundamentals of cyclones are reviewed briefly, where a typical cyclone is considered. Graphical cyclone data available in the literature have been converted to mathematical equations for convenience. Preliminary selection and design procedures for both cyclones and pumps are provided, and a sample calculation for a hypothetical grinding circuit is covered in some detail. In general, cyclone and pump suppliers should be consulted for definitive design purposes. Some cyclone suppliers currently employ digital computers for definitive design to ensure greater accuracy.

Jan 1, 1978

By Max Barber

PRESENT equipment and practices in open-pit mines of the Lake Superior iron ranges have been described recently in some detail by A. H. Hubbell.1 It is anticipated that any further improvements will be the result of gradual evolution of present methods and equipment, just as those now used have been gradually evolved from earlier methods. An exception to the process of gradual evolution during the last decade has been the adoption of electric power for operating shovels and trains in open-pit mines, but it is not expected that any such revolutionary changes will be made in the future. The use of Diesel, engine equipment will gain considerable headway, no doubt, and will find favor in certain lines of operation as improvements and adaptations are evolved to meet particular requirements. The question of installing belt conveyors for handling material from deep mines of restricted area, where haulage grades become a serious consideration, or even for transferring earth, rock, or ore material for distances of several miles, is now being studied and some very interesting data are being obtained.

Jan 1, 1932

By Richard B. Greenwalt, John M. Bertram, George E. Aiken

Agglomeration developments in the iron ore industry of North America over the past twenty years are closely related to shifting patterns in commercially acceptable ore grades and even the definition of iron ores. As early as WW II the rich Mesabi hematites were depleted, ending a 50-year era of direct shipping ores that included reserves of an estimated three billion tons. Decreasing ore grades and rising costs began to force the closing of many underground iron mines and processes were being developed to use domestic low-grade iron deposits. This resulted in the rapid development of iron ore beneficiation processes and signaled the coming trend toward concentration, sintering and pelletizing. Yet even today when agglomeration facilities are treating 90 % of the Mesabi Range product much remains to be done in keeping world-wide competitive forces in check and in ensuring the long- term utilization of these expansive ore supplies in an up-until-now captive U.S. market.

Jan 10, 1973

Natural leaching of minerals has been recorded for some two millenia but surprisingly only in recent years has enough been known of the process for any serious design to be made. Copper has been recovered from natural mine waters since about the 17th century but again little progress was made in de- sign procedures until recently. Natural or dump leaching was started as a recovery process late in the 19th century and in the years up to the classic study of Taylor and Whelan in 1943 a series of impirical optimis- ations made it a valuable process for treating low grade or waste material. The biological nature of Sulphide leaching was proven by Colmer and Hinkle in 1947 and since then a large mass of data has accumulated on the microbiology, biochemistry, and response of ores to this form of attack. In spite of this knowledge and the vast amount of pract- ical experience available there are few recorded attempts to present methods of calculation or design procedures that can be used for setting up a leaching process. A framework is given here on which such procedures can be based and indications given of the inherent advantages and limitations of the process,

Jan 1, 1969

By H. Huang, J. C. Wu, C. H. Xie, Y. Q. Xue, Z. H. Zhang

Two- and three-dimensional groundwater flow models for dewatering in an opencast mine are presented. The models focus on solving special problems using numerical simulations of the opencast mine. These special problems include the drying up of the aquifer, the movement of the model boundary and the prediction of the residual head. These models are used to describe the decline of groumdwater levels in the Yuanbaoshan Opencast Coal Mine and its neighboring area during the drainage period. The simulated values agree very well with the field data. There have been several successful examples of numerical simulation for predicting the mine dewatering rate in an opencast mine. However, The hydrogeological conditions for the Yuanbaoshan Opencast Coal Mine are rather complex, and the total average flow rate is very high at 4.676 x 105 m3/d (1.65 x 107 cu ft/day). In this paper, a two-dimensional groundwater flow model in a large area is developed to solve the problems mentioned above by simulating regional drawdowns of the groundwater level during the drainage period, and a three-dimensional flow model is developed to simulate the residual head near the open-pit bench.

Jan 1, 1998

By Victor Rudenno

Feasibility studies for mining projects traditionally involve in their final stages a lengthy process of repetitive trial and error discounting, in calculating the discounted cash flow rate of return resulting from the respective yearly after-tax cash flows. Also, probability analysis and sensitivity analysis (in particular) require extensive additional calculations with each change of any project parameter . These inefficient repetitive procedures have two unacceptable results: 1. they are not flexible enough to allow ready analysis of dependent parameters , and 2. they require resort to high-capacity centralised computing facilities with their inherent impersonality, rather than a convenient and available desk calculator - a factor of particular importance to top mining management. Such problems can be overcome if the mining project can be represented by a reasonable straightforward mathematical economic model. The most flexible and appropriate model has been found to be one in which a maximum and minimum value for each of n parameters are supplied to a program which determines a large number of systematic combinations of parameter events and then statistically analyses them to determine the resulting coefficients of the model. In this paper the authors discuss the selection of the most appropriate type of model and outline the steps followed in its development and application.

Jan 1, 1977

By G. Mitchell

Much debate has ensued over the past few years on the speed of transformation in the mining industry. By transformation is meant the degree to which the industry has met the requirements of the Mining Charter. In response to this, the Department of Mineral Resources (DMR) commissioned a research study in 2009 to ascertain the degree of industry compliance. The mining industry in response made a presentation to the Minerals Portfolio Committee in Parliament in 2011, during which it released aggregated figures on industry compliance to the Mining Charter. The conclusions of both of the studies are widely divergent. It is argued in this paper that both processes are flawed. The government-sponsored research is empirically and methodologically weak and the results therefore have to be taken with a great degree of caution. The Chamber of Mines figures, on the other hand, while faithful to the reporting of the Chamber member companies, do not represent the entire span of the industry but only the larger mining companies. It is further argued that in order to ascertain a true reflection of the industry an independent audit be undertaken using recognized social scientific survey methods.

Jan 1, 2013