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By Ross R. Bhappu

Anticipating a major power cost increase in 1990, Cyprus Copper Company decided to modernize the Miami Smelter at a cost of $92.5 million. The modernization project included the addition of an Isasmelt vessel for use as the primary copper smelter and the modification of the existing electric furnace to a slaglmatte separating vessel. The project was completed in June of 1992 and is currently operating at close to its design capacity. This paper provides a summary of the decision making process, a description of the project, a summary of start-up problems and solutions and the current status of the smelter operation.

Jan 1, 1994

By R. C. Bryce, G. S. Martin

"Aur Resources Inc. is the operator of the Louvicourt Mine located 40 km east of Val d'Or. Quebec. Les Entreprises Minieres Redpath Limitée a member of the 1.S. Redpath Group of companies was contracted to construct two vertical mine shaft collars in deep overburden.During the spring of1991 two vertical shaft collars were established in wet, running sand that was in excess of20 m deep. This paper will illustrate the engineering and construction techniques used in establishing these collars and the methods used to overcome the various obstacles that occurred during construction.IntroductionThe Louvicourt copper/zinc/gold/silver deposit is located 40 km east of Val d'Or, Quebec, is adjacent to the former Louvern Mine which operated at depths of 40 m to 850 m below surface (Fig. 1). This deposit was discovered in mid-1989 as the result of systematic exploration and diamond drilling based on a geological model. The Louvicourt project is operated by Aur Resources Inc.The property is being developed to produce 4000 tid with an anticipated life of just over 17 years. Mill start up is scheduled for July 1. 1994, commercial production October I, 1994, and full production by late 1995. The current production plan provides for 24 040 (XX) t averaging 3.89% copper, 1.95070 zinc, 0.039 oz gold per tonne and 0.99 oz silver per tonne, to be mined."

Jan 1, 1994

By Ivette E. Torres

World investment 10 all mineral and mining industry sectors is not available. However, partial information available provides some information useful for analysis. Information available in this section covers limited geographic information on investment in the steel industry, limited information for petroleum industry capital spending, and total U.S. foreign investment in comparison to the mineral-related sectors (tables 13, 14, and 15). Annual steel industry investment is available for the European Community, almost all countries within the European Free Trade Association (EFTA), Latin America, and other countries with significant mineral industries, such as Canada, Japan, and the United States. Although information was not available for 1992, data for 1991 indicate that for those countries aforementioned, total investment increased by 8 %. However, investment patterns were very different within the different groups of countries. While the European Community had a net increase of 12 %, dominated by an almost °40 % increase in Germany, EFTA member countries had a 26 % decrease in investment for the same period. Investment in EC countries was almost seven times that of EFT A countries. Japan's investment in the iron and steel industry, by far the largest of those available, almost twice that of the EC and almost four times that of the United States, increased by more than 20 %. In North America, investment in Canada and the United States decreased. Almost all of Latin America decreased investment in the sector. The notable exception was Mexico, with a 60 % increase. Changes in Mexico's investment policies of the recent past, its economic growth, and privatization of its iron and steel industry are some of the reasons for such an increase. The other country covered individually in Latin America, where investment in the iron and steel industry increased, although slightly, was Argentina. This limited information does not allow a comprehensive analysis of global industry trend, which in turn impacts many other mineral commodities, and with the transition in many countries within Europe and Central Eurasia that are now effecting the steel industries of the countries that were members of the U.S.S.R. and its CMEA partners, it is most regrettable that comprehensive and comparable data, both current and historic, on investment in this area are not available.

Jan 1, 1994

By Anupam Madhukar

The essence of an atomistic unified kinetic model of strained thin film growth and defect initiation is presented along with a comparison of its consequences obtained from computer simulations with experiments. Within the competing kinetics of a strain dependent activated incorporation of atoms and an asymmetry between upwards and downwards inter-layer migration, the model provides a consistent description of 2D versus 3D morphology evolution accompanied by the appearance of surface vacancies and steps at no energy cost. The correlated migration of these precursor defects offers an atomistic mechanism for the emergence of surface half-loops from the growth front (thus accounting for configurational and thermal entropy) governed by activation energies closer to their correlated motion under the evolving strain fields and thus substantially less than those calculated with respect to the perfect crystal as the reference state. The essential mechano-chemical nature of the problem is compared and contrasted with the historical literature of such phenomenon as precipitation hardening and sintering in metallic and ceramic composites.

Jan 1, 1994

By A R. Cameron

"The number of commercial explosive products available to the mining industry has been steadilyincreasing and associated with this there has been an increase in the range of characteristics or properties of them. This has lead to increased difficulties in selecting the most appropriate explosive for a particular blasting situation. Techniques are available that can be used to evaluate and compare the characteristics of explosives under a range of conditions. Also, the techniques are used to assess the variability in the characteristics between batches."

Jan 1, 1994

The strength of anchorage of various types of roof bolts in permafrost depends on the types of rock in which they are installed. Variation in the mine thermal regime results in weakening of the roof and walls, and at times total loss of ice cement bonds takes place in the surrounding rockmass. In mines with positive ventilation air temperature, the wedge or expansion types of bolts may become weakened due to the transfer of heat into the anchorage through the metal rod and subsequent thawing of rocks. Effective operation and evaluation of roof bolt systems for mine workings in permafrost require predictions of the dynamics of wall thawing by warm ventilation air. This paper presents an analysis of the temperature distribution in the frozen host ground surrounding roof bolts, the area of interest being the vicinity of the anchors for point anchored bolt and the entire length for split set bolt

Jan 1, 1994

Gold mineralisation was first noted in 1983 at the Wapolu Point area of Fergusson Island, Papua New Guinea (PNG) during a follow-up regional reconnaissance program. Subsequent exploration programs through to late 1987 completed 22,147m of costean trench sampling, 553 aircore/RC/diamond core drill holes (16,970.5m total) and metallurgical testwork, predominantly on the Wapolu grid in two mineralised areas.Subsequently in 1988, geostat-istical global and polygonal resources were calculated for the main mineral-ised zones, Didigayagaya and Dagwalala. In 1992, a 'probable total reserve' of 1.9Mf @ 2.4g/t with a 1.2g/t cut-off was calculated for these prospects.

Jan 1, 1994

By A. Kijko, C. W. Funk

Methods for the analysis of seismic hazards in mines are reviewed as illustrations of the techniques that are being used in some South African mines. The classical parameters that describe a hazard are the seismic activity rate, ?, the Gutenberg-Richter value, b, and, occasionally, the maximum regional magnitude, mmax The activity rate is calculated readily owing to the inherent simplicity of its definition. The evaluation method presented for the Gutenberg-Richter b value takes into account the presence of mmax Three statistical procedures are described for the assessment of mmax which the maximum observed magnitude, Xmax a crucial role. Often, the configuration of mine seismic networks is changed, or the networks are improved, which inevitably gives rise to changes in the completeness of the seismic catalogues. The routine analysis of seismic hazards must account for these time dependent changes. A method for the evaluation of hazards is reviewed that accommodates varying levels of quality in the catalogues. Finally, the concept of the volume of ground motion (VGM) is presented. This is a technique that allows for most aspects of seismic hazards in mines. The advantage of the VGM is that a hazard can be described by one physically significant value: the volume of rock (cumulated over a time period) in which the ground motion exceeds some critical particle velocity. Data from the gold mining region in South Africa known as the Far West Rand is used in a demonstration of the discussed methods of hazard analysis.

Jan 1, 1994

By W. J. Przybylowicz, V. M. Prozesky, D. de Bruin

"The common style of gold mineralization in the Basal Reef and other auriferous conglomerates of the Witwatersrand Supergroup comprises clusters of gold grains occurring interstitially to quartz and pyrite pebbles as well as gold accumulations attached to the surface of and infilling hairline cracks and fractures in round, compact, detrital pyrite. The latter textural association is generally interpreted as a result of remobilization of originally detrital gold during regional metamorphism and related hydrothermal fluid circulation. There is general agreement that, although gold solubility was low, ore modification occurred during the metahydrothermal event, but uncertainty exists about the magnitude and scale of gold remobilization.Micro-textural and chemical investigation of compact round pyrite and associated gold accumulation has established that gold is preferentially deposited on chemically heterogeneous pyrite surfaces. Combinations of alternating high- and low-As zones in pyrite result in mixed np-type conductivity accompanied by electron exchange and the reduction-driven deposition of gold at the cathode. This model does not explain gold accumulations which are not immediately linked to chemical heterogeneities and it is inferred that an additional control on the deposition of gold was exerted by physical defects which lead to zones of increased charge density and/or areas of focussed conductivity. The inferred precipitation mechanisms suggest that submicrocopic physical and chemical controls are the important factors that determined the sites of gold nucleation and that precipitation mechanisms based on physicochemical changes of the hydrothermal system were not involved. The Basal Reef contains on average close to 5OJo of round, detrital, chemically zoned pyrite which provides a large number of electrochemically active pyrite surfaces. The extremely effective electrochemical precipi- . tation mechanism together with the low solubility of gold in Witwatersrand fluids is the main reason for the spatially restricted remobilization of gold in the conglomerate reefs."

Jan 1, 1994

By Dale W. Collins

The disposal of arsenic from copper operations possess various health, environmental and processing problems. There are basically two areas of concern. The first being the disposal or treatment of smelter flue dusts and the second the removal of arsenic from refinery electrolytes. A number of treatment options have been proposed including the addition of soluble arsenic wastes to copper heap and dump leaching solutions. This approach will allow arsenic to be reintroduced to the ore via Solvent Extraction (SX) raffinate associated with hydrometallurgical operations. Knowledge of the attenuation behavior and mechanism during leaching is important in determining the long term stability of arsenic and the success of this approach. Parameters, such as uptake capacity, pH, particle size and solution chemistry have been investigated. Arsenic attenuation has been examined using column leaching with experiments employing both continuous flow and pulsed additions of As(V). In the initial stages of leaching, the attenuation of arsenic appears to depend on the pH and iron concentration in the effluent. Arsenic stability in the copper oxide ore has been examined with rinses of progressively lower pH.

Jan 1, 1994

By D. S. Brown

Few issues pose quite as profound consequences to the quality of life and the creation and distribution of wealth as how we protect the natural environment. No longer a peripheral but a global concern, the environment, once almost nobody's business, has now become everybody's business. It is also the single biggest issue facing mining and mineral activities. This heightened ecological awareness and sensitivity have spawned a new commitment to restore, protect, and preserve nature. But that very commitment poses difficult socio-economic trade-offs, such as: What and how many resources can be given up to prevent and reduce pollution? What are the opportunity costs associated with meeting higher environmental standards? What problems are more important or pressing than others and should be given priority? Choices have to be made that may entail unintended consequences for other societal goals.

Jan 1, 1994

By C. Braux

The aim of this study was to develop an integrated approach to enable identification of areas favourable for the presence of massive sulphide deposits in a given region (Las Herrerias, Spain). It is based on geochemical soil exploration, geophysical surveying (ground gravimetry), detailed geological mapping and a knowledge of the deposits of the South Iberian Massive Sulphide Belt. The multi-dataset approach consists, in the first instance, in standardizing and combining all the geochemical data with reference to their geological setting. Next, the "heavy" anomalies are extracted from the gravimetric survey, regardless of the surrounding context (heavy or light). The results from these two stages are then crossed, so that areas where heavy anomalies are associated with geochemical anomalies can be identified and classified. Crossing the geochemical and geophysical data enables a much tighter selection of anomalies than does the manual superposition of data provided by each method (geology, geophysics, geochemistry).

Jan 1, 1994

By William F. Riggs

In the fresh application of a frother, collector, or the change of any particular reagent, the interaction caused by this change is often overlooked since we attempt to solve a problem or improve a situation with use of a particular reagent without regard for the Interactions or side effects. When a particular reagent is added to a flotation circuit or substituted for another reagent, a series of chemical reactions occurs which. In turn, will create different physical responses. This discussion will provide a series of examples which have actually been experienced by the author.

Jan 1, 1994

By Huyang Xie, Rishi Raj, Vera A. Versteeg

"A new method for MOCVD has been developed in which a precursor solution is directly injected into a reaction chamber. The vaporization of short pulses of liquid is facilitated by atomization with a piezoelectrically-operated nozzle. The system has been used successfully to grow oriented, thin Ti02 (rutile) films on sapphire substrates with the crystalline relationship (101)[010]R I (1120)[0001]s. A growth rate of approximately 2 monolayers per pulse was achieved at 650°C for a reactant impingement rate of about 800 monolayers per pulse. Also, epitaxial LiTaO3 thin films were grown on (0001) sapphire from a single source, bimetallic precursor, lithium tantalum hexa-t-butoxide as the precursor. X-ray diffraction shows that the LiTaOa c-axis is normal to the sapphire surface. The x-ray pole figure and crosssection TEM diffraction show that the films were also in-plane oriented, with sapphire [1010] parallel to lithium tantalate [1010]. These films are shown to have extremely low optical attenuation, and refractive index that compares well with bulk values.IntroductionMetalorganic chemical vapor deposition (MOCVD) techniques have come into increasing use in recent years, due to the growing versatility and availability of precursors and improved environmental advantages over the halogenated compounds used for conventional CVD. Most commonly, the films are deposited by dissolving the metalorganic reactant (typically a metal alkoxide) in a carrier gas, which is carried through heated lines to a heated substratel . The metal alkoxides decompose by pyrolysis, leaving the films on substrates. While this method has been used to produce excellent epitaxial and heterepitaxial films, it has the disadvantages of complexity: the precursor must be heated to fix its vapor pressure, the gas flow rate carefully controlled, and the carrier lines heated to prevent condensation before reaching the reactor. Additionally, this conventional method cannot be used with certain low-volatility precursors that decompose upon heating."

Jan 1, 1994

Simulation has established itself as an accepted tool for the design and optimization of complex minerals processing plants. This paper addresses the use of simulation as a tool for the design and optimization of carbon-in-pulp and carbon-in-leach (CIP/CIL) plants. The complex, interactive nature of CIP/CIL plants makes detailed experimentation an expensive and time consuming approach to CIP/CIL plant design and/or optimization. This paper discusses a simulation-based software tool that can make the process of CIP/CIL plant design and/or optimization much more cost effective. Many of the issues and problems pertaining to the use of simulation for CIP/CIL design and operation are generic. Thus, this paper also attempts to highlight generic issues that must be solved before simulation will become a more widely used design and optimization tool. Requirements for the application of simulation for CIP/CIL plant design and optimization are highlighted. Similar problems and issues can be identified for most mineral processing plants.

Jan 1, 1994

By Yi Luo

The responses of a section of railroad to ground subsidence process was monitored as it was undermined by a longwall panel. The subsidence data collected and the observations made through this monitoring program could help us understand betteer the ground subsidence process and its impact on linear structures such as railroads. The data analysis techniques used and the assessment methods presented could be useful to researchers practitioners in the field of mining subsidence.

Jan 1, 1994

By F. Goodarzi

"The nature and distribution of the inorganic components and the concentration of certain environmentally sensitive elements, such as, As, Sb, B, Hr, Cd, CI, F, Mo, Pb, S, and Se, or elements detrimental to the utilization by industry such as B, Na, P and S are very important in determining coal quality. The concentration of elements in coal is controlled by the following factors: (1) frequency of occurrence of partings; (2) nature and habit of occurrence of minerals in coal; (3) environment of coal deposition; (4)rank; (5) geological setting; and (6) weathering.Selective mining of coal can reduce the input of undesirable elements such as As and S by eliminating the part of the seam which is enriched in these elements. IntroductionCoal is a sedimentary rock of plant origin and consists of two components: an inorganic component (minerals) which is formed by influx of clastic sediments into the coal-forming environment and also by activities of groundwater, and an organic component (macerals) which is formed from plant debris deposited in the original coal-forming environment. However, coal is a generic term with a broad range of utilization characteristics. A coal that is attractive for use in one market - such as generation of electricity (combustion) - may not necessarily be acceptable for use in another, such as for production of coke (Davis, 1978).The elements in coal are associated with both macerals and minerals. The elements associated with coal macerals, such as C, H and N are termed elements with organic affInities. The concentration of elements with organic affmities (including B, Br, CI, F, I, S, and Mg) often decrease with increasing ash content of coal (Nicholls, 1968; and Finkehnan,1982). FIgure 1 shows such a trend for chlorine. Some of these elements may also be incorporated in coal maceral as very fine mineral grains (Finkelman, 1982). The elements with organic affmities are often volatilized during combustion and carbonization of coal and emitted in the vapour phase. Emission of some of these elements (C, 0, Br, N and S) is of major environmental concern (Lim, 1979)."

Jan 1, 1994

By Jon C. Volkwein

The U.S. Bureau of Mines has developed a method to measure methane and other gases during the auger mining of coal. An intrinsically safe commercial gas detector with a built-in data logger was mounted in the center of the hollow conveying auger. A sampling head through the wall of the auger conducted a gas sample to the detector. Results showed that gas levels can be monitored on a continuous basis during the auger mining of coal and the data retrieved upon completion of the hole.

Jan 1, 1994

By S. M. Hay

The zinc content of blast furnace and basic oxygen furnace dusts is low compared with electric arc furnace dusts and it is generally not economical to treat the dusts to recover zinc. However, they have a high iron content and removal of the zinc would allow recovery of the iron values. A literature review and thermodynamic analysis was undertaken and, as a result, several smelting options were identified. This paper describes experiments undertaken to develop understanding of metallurgical aspects of these processes which are not amenable to theoretical analysis. Dusts from an Australian steelworks were characterised in order to determine their mineralogical make-up and the form of the iron. The processing aspects investigated in the laboratory were slag-metal equilibrium and solid-state pre-reduction using reducing gases of compositions expected from bath-smelting processes. Particular attention. was paid to the deportment of zinc, sodium, potassium, phosphorous and sulfur between the phases formed during smelting and pre-reduction. The smelting results indicate that less than 10% of the zinc, sulphur, sodium and potassium report to the metal. About 99% of the zinc and potassium and about 80% of the sodium could be volatilised from the dusts by reducing them at 1,000°C with mixtures of CO, CO2, H2 and H2O even when metallic iron was not formed. The experiments indicate that smelting of blast furnace and basic oxygen furnace dusts should produce hot-metal of a composition which can be blended into the main stream of hot-metal in the steelworks.

Jan 1, 1994

By S. W. Stogran

"Chemical and limited biological monitoring of mine and mill effluents are being used by regulatory agencies to monitor and control discharges to the environment. Amendments to the Federal Fisheries Act may make it mandatory for mines to conduct Environmental Effects Monitoring (EEM) which will change the emphasis from monitoring effluents to monitoring impacts on receiving waters. The EEM amendments may expand the scope of present environmental studies to include: effluent mixing zone delineation; inventory and classification of resource, habitat, and historical receiving environment; effluent quality determination; chronic and acute bioassay testing; tissue analysis; benthic invertebrate monitoring; fish population surveying; fish tainting evaluation; and the evaluation of impacts on fish habitat, invertebrate communities and fisheries resources. The requirements for EEM have not yet been worked out by the mining industry and the government committee. Experience at Lakefield Research in conducting biological monitoring studies for the mining industry has shown that biological monitoring may be useful for assessing environmental impacts only if programs are planned and executed to collect relevant data, thus minimizing costs and maximizing effectiveness.IntroductionThe chemical monitoring of effluents and water bodies receiving effluents is common practice in the Canadian mining industry and has been used routinely by regulatory agencies to control discharges to the environment. Biological monitoring has also been used on a limited basis, primarily to augment chemical data collected. A number of regulatory bodies, primarily in Canada and the United States, have been incorporating biological monitoring into environmental regulations.Various forms of biological monitoring techniques have been used in Canada and the United States to help assess the impact of mining operations and effluents on the environment. Biological monitoring includes a wide range of activities, from monitoring metal uptake in individual organisms to examining the population dynamics in ecosystems. The most commonly employed biological monitoring techniques are the chronic lethality toxicity tests. Also becoming widely used are in situ and chronic toxicity tests."

Jan 1, 1994