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By Jay W. H, Brown L. J

Several case studies are examined in which analysis of treated ores and extracted metal species by Mossbauer spectroscopy provides information not available by other competing techniques. The cases include poorly crystalline, surface iron oxides in titanium minerals and chalcopyrite, gold in ores and bacterially oxidised ores and the adsorbed species from gold extracted from cyanide and chloride solutions onto activated carbon and polyurethane foams. Some limitations on the use of the technique in terms of sample size, sensitivity and counting time are also discussed.

Jan 1, 1997

By Maslov LA

We have considered the following characteristics of the crust and upper mantle of the Pacific Belt: seismic wave velocit> anomalies, mechanical stress and shear deformation rate fields, heat flow and the pattern of metallogenic provinces of the Belt. It has been noted that there exist certain regularities in distribution of the above mentioned geophysical characteristics and metallogenic zones within the Belt, displayed by prevalence of the lithophile elements in the Asia-Australian part of the Belt, and of the chalcophile ones within the American part.

Jan 1, 1995

Interaction between rock and fluid plays a critical role in rock engineering ventures such as stimulation of oil and gas wells, geothermal energy recovery and nuclear waste isolation. Robust and reliable design of the related services and underground facilities is based on understanding of the mechanics and chemistry of the coupled hydromechanical- thermochemical processes. This paper explores the application of the theory of such processes in minerals engineering, with particular reference to rockburst mitigation, in situ solution mining and cavity completion of coal-bed methane production wells.

Jan 1, 1995

By Zhou A, Cadogan J. M

Direct reduction of iron ore (DR) is one of the promising technology emerging in the world's steel industry. Kinetics and Mossbauer studies of DR with hydrogen have been carried out at two temperatures of 600¦C and 800¦C in this investigation. The results show that different controlling steps govern the reduction rate at different temperatures. The mechanism was also found to vary during the reduction. The Mossbauer spectra of the samples reduced in various time intervals were studied to determine the phase changes during reduction.

Jan 1, 1997

By Thimons E. D, Derick R. L

In early June, 1986, a fire of unknown origin erupted in one of several main entries of a coal mine located in southwestern Colorado. The fire was aggressively fought with high-expansion foam. As a result of several strategic decisions, the fire appeared to be held in-check. Unfortunately, sufficient quantities of foam were unavailable and as soon as the foam was depleted, control of the fire was lost. To prevent further damage and the possibility of an explosion, all entries to the mine were sealed.

Jan 1, 1988

By Rosentreter N

Difficulties with froth flotation recovery and vacuum de- watering equipment for the treatment of fine coal have been investigated. Mechanical alterations to cyclone desliming banks, and flotation cells are described. A large disc filter has been replaced by two drum filters for dewatering, and the improvement in plant. operation is discussed:

Jan 1, 1978

Aspects and anomalies in the present Standard Specifications for Blended Cements which may have operated in Australia against the development of the greater use of Slag Blended Cements are noted. Estimates of slag and ash usage in Australia are given and the need for further research with local materials stressed.

Jan 1, 1979

By Harraway D. H, Draper N

The association of graphite with a fine grained pyrite in the Mount Isa lead-zinc ore was investigated from mineralogical and metallurgical standpoints. The pyrite has been partially or completely replaced by galena and to a less extent by sphalerite, pyrrhotiteand chalcopyrite with the retention of graphite films or inclusions. During lead flotation the graphite imparts a spontaneous flotability to all associated minerals, resulting in a low grade fraction, which we call the carbonaceous fraction, floating with and diluting the lead concentrate. In times of low metal prices this fraction seriously reduces the economic value of the lead concentrate. A flotation procedure was developed to upgrade the carbonaceous fraction separately, producing an economic concentrate and a tailing.INTRODUCTIONThe lead concentrate produced from Mount Isa ores can vary from 20 to 50 per cent lead, depending on the locality in the mine from which the ore is obtained. Variations of this order are independent of ore grade and lead recovery. The large variation is related to the presence in the ore of a variable fast floating low grade fraction known locally as the carbonaceous fraction because of its association with graphite. During conventional lead flotation with sodium ethyl xanthate the carbonaceous fraction floats rapidly and unselectively with normal Mount Isa galena.The paper discusses mainly the examination and treatment of an average carbonaceous fraction, defined here as the fast floating material in the mill feed of late 1956. The ore was drawn from the Mount Isa Black Star orebodies. The fraction represented about 5 per cent of the total ore...

Jan 1, 1961

Segregation studies in ternary systems of glass ballotini, iron ore and coke particles (with size range of 1-8 mm in each) in filling and emptying a laboratory size Paul Wurth hopper are described. In-bin segregation is shown to be a function of the position in the hopper, the nature of the material and the feed composition. The in-bin results are correlated by the equation C = C0k, where C and C0 are the size compositions (wt per cent) in the hopper and feed respectively, and k is an experimentally obtained segregation constant. The results of now pallern measurements show that material discharges from the hopper according to the sequence; core now - wall now - scaffold now, where the latter represents stagnant material at the hopper wall that discharges last. Size segregation in the discharge stream from the hopper is shown to be a function of in-bin segregation and hopper now pallern. A method of predicting discharge segregation from these two sets of data is suggested. The results of the model studies are also compared with industrial data and these show satisfactory agreement. Discussion of the hitherto ignored effect of size segregation on hopper now rates, stoppages and other operating problems is also included.

Jan 1, 1985

By A D. Paktunc

The surface reactivity of underwater deposited, high-sulfide copper mine tailings was evaluated under fresh and saline water cover conditions by measuring the surface and pore water quality as a function of time. The experiments were conducted in aquarium type lysimeters having a shallow, well-aerated water cover up to approximately 0.25 m over the tailings. Natural lake water was used for the fresh water cover and seawater for the saline water cover scenarios. The tailings showed significant surface reactivity and oxidation under both fresh and saline water cover conditions. The surface water quickly became moderately to highly acidic, and surface oxidation of the tailings resulted in increased dissolution and release of sulfates, iron (total), calcium, magnesium, aluminium, manganese, copper, nickel, zinc, lead, cobalt and silicon to the water covers. A moderate to slightly increased loss of total sulfides, including pyrite, chalcopyrite and sphalerite, occurred in the tailings surface layer to a very shallow depth. In comparison to the fresh water cover, the complete acidification of the saline water cover was delayed by approximately 30 - 40 days because of its additional available alkalinity. Whereas the rate of surface water acidification and release of aluminium and silicon were moderately reduced under saline water cover conditions in comparison to those for the fresh water cover, the release of calcium, magnesium, iron (total), copper, nickel, lead, zinc, sodium and potassium were enhanced. The mass transfer fluxes for dissolved copper, nickel lead, zinc and iron (total) from the tailings substrate to the surface water cover following surface water acidification were higher by 50 per cent or more in the saline water cover than those in the fresh water cover. This release was also reflected in moderate loss of pyrite, chalcopyrite and sphalerite in the very shallow upper surface layer of the tailings at the tailings-water interface, although the loss of pyrite in the surface layer was less pronounced. In both cases, the dissolution of aluminosilicate minerals moderated, to a certain extent, pH and acidity in the water cover.

Jan 1, 2003

By Tucker A. J

An overburden blast utilising horizontal blast holes was successfully attempted at the Ulan Coal Mines during December 1991. The blast reduced operational problems and costs and improved dragline productivity in an area of that contains poorly consolidated sands and clays overlying very hard Permian strata.The fan shaped shot consisted of seven 250 mm diameter holes between 80 and 95 metres long drilled into the highwall face. The holes were loaded with ICI Powergel Gold 25606 bulk Emulsion explosive. The design powder factor was 0.15 kg/bcm for the total shot of 180 000 bcros and 0.44 kg/bcm for the competent Permian strata into which the holes were drilled. Fragmentation from the horizontal blast was comparable to areas conventual blasted. Following the success of this shot further shots are planned for this area.

Jan 1, 1992

By R Vleggaar

In addressing a short-term operational need for the relocation of a tailings storage facility reclaim pond, a mine has achieved a host of water management objectives. Through effective planning and adoption of a strategic æwhole of mine lifeÆ approach, the mine has achieved significant environmental, social and economic benefits. A review of all water management aspects across the site identified a host of other interrelated water issues and concerns which, if dealt with individually, would prove too costly for individual operational departments. When considered as a whole, however, the issues became opportunities and provided the stimulus for integration of the site water management system. The development of site water and solute balance models provided the tool by which a number of water management options/strategies could be evaluated. The conceptual design and costing of the proposed water infrastructure further facilitated the evaluation of the multiple benefits to be gained from each option. A business case could then be made to mine management for the preferred option. The recommended water management strategy finally recommended to the mine not only provided a tailings storage facility (TSF) reclaim pond, but also provided for:increased wastewater recovery from the TSF, the capture of all waste rock dump run-off, additional water harvesting from local creeks, increased wastewater reuse, improved environmental water management, infrastructure that could be used by the local community after mine closure, and overall cost savings. This paper illustrates how effective water management planning can provide both short-term economic and environmental benefits, as well as long-term social benefits.

Jan 1, 2006

By Pollard D, Meadows N

The presence of impurities which are electropositive to zinc in acid zinc electro- lyte causes changes to deposit morphology and reduced current efficiency. Glue may be added to control some impurity effects, but assaying for animal glue concentration is difficult and seldom done. Measurement of the activation overpotential for zinc deposition by cyclic voltammetry is used in some plants to monitor electrolyte quality and control glue additions. The deposit morphology and current efficiency of zinc deposition from commercial electrolyte were investigated for various glue additions in the presence of increased levels of antimony. Cyclic voltammetry was invest- i,ated as a method of optimizing glue additions in the presence of antimony. Scanning electron microscopy showed deposits characteristic of the impurity element present and the glue addition rate. Cyclic voltammetry measurements showed some correlation between current efficiency and activation polarization potential. The importance of using tankhouse electrolytes where results are to be related to tankhouse operation was noted.

Jan 1, 1984

By Clark K. N

The need for and advantages of simulators in iron ore pellet induration research are described. The approaches to simulation and the techniques to carry it out are discussed in detail covering drying and firing for the straight grate process. The CSIRO simulator design is described and some errors in simulation are discussed.

Jan 1, 1974

Following a summary of aerodynamic principles and the changes imposed by the process, areas important to the operator are then enumerated. These include furnace lines, cooling and casting technology, coke properties, gas distribution and others. Questions are raised on the implication of lowering the hearth substantially below the tuyeres and about the status of stack injection. Finally, the future developments are identified as being those associated with gas volumes required to pass through the furnace stack per unit time or per tonne of product.

Jan 1, 1975

By Diehl GW, Kuntonen J

The Tamrock all-hydraulic rock drilling system 400 has been developed to cover as wide a drilling range as possible, from 35 mm holes in tunnelling, roofbolting and development work to 64mm holes in long hole production drilling. Field experience during the last five years shows that the Tamrock drill covers this range in a way that no other rock drill on the market does and recently the range has been success- fully further expanded to cover bench drilling with 76 mm holes.

Jan 1, 1978

Operation of a pilot heavy medium separation plant allows flexibility of operation not normally possible in an operating plant. Much useful data can be obtained, although some limitations apply. Projects carried out at AMDEL have included HMC separations at 1.5 to 3.6 specific gravity, comparative operation of HMC and DWP separators and the use of fine feed and product screens. Investigations of this type have provided a considerable amount of information on HMS plant performance and characteristics under a wide range of operating conditions.

Jan 1, 1987

Benchmarking of mining operations has been in vogue for a number of years: it seems teams are forever flying around the world to try to understand what other operations are doing. However, unless a benchmarking exercise involves data gathering at a fundamental level and a rigorous analysis process is applied, the trip will be nothing more than industrial tourism. When benchmarking is performed thoroughly, the range of comparisons that can be made is extensive and informative, and need not be restricted to sites with similar conditions and equipment fleets. This paper describes the detailed and rigorous process for benchmarking used throughout AMC benchmarking studies. The paper demonstrates how, through drilling down to the underlying drivers, the often heard cry of æyou canÆt compare us, weÆre differentÆ can be overcome. Included in the discussion are a number of significant issues that have been identified during AMC benchmarking studies. The paper then considers the types of opportunities that have been identified and the potential for improvement. The paper concludes with a discussion of the implications for planning, measuring and management of operational performance.

Jan 1, 2003

By Susanto A

As part of the current NERDDC funded project studying Dragline/Hopper/ Crusher/Conveyor systems for overburden removal, an investigation was carried out to assess the feasibility of automating the swing-to-dump phase of the dragline digging cycle in order to main- tain consistent performance of spotting the bucket above the hopper prior to dumping. The study involved design of automatic position controls for the hoist, drag and swing drives and simulation of detailed mathe- matical models of the three electromechanical systems and their associated electrical control schemes. The design of the hoist and drag systems to position the bucket in the boom plane is relatively straightforward. Simulation results show fast and accurate performance, with no evidence of interaction between the two drive systems through the ropes. The design of the swing position control system involves special strate- gies to cater for variable inertia and to damp the pendulum oscillations of the bucket. The use of a bucket pendulum model and variable dynamic compensation embedded within the feedback control loop, along with optimal speed/angle slowdown trajectories, has yielded fast and damped positioning responses under simulation.

Jan 1, 1989

Alaska Native corporations, as representatives of the aboriginal inhabitants of Alaska, control the mineral rights to 18 million hectares of Alaska, approximately 12% of the state. These corporations were established through legislation passed by the United States Congress in 1971 designed to settle the land claims of the Native peoples of Alaska. Twelve corporations, each representative of a specific geographic and cultural region, were established and granted the mineral rights to most Native lands in their respective regions. Since that time the Native corporations have taken an active role in mineral development in the state. Generally through agreements with established mining companies, Native corporations encourage balanced exploration and development of their lands. Substantial mineral potential has been recognized on Native corporation land, which includes holdings in many historic mining districts of Alaska. Several world class deposits have been discovered on Native corporation land, including the Red Dog zinc-lead deposit, which began production in late 1989. The experience of Alaska Native corporations demonstrates that aboriginal peoples can be very positive forces in resource development.Alaska, although remotely located in the Northeast corner of the Pacific Basin, is playing an increasing role as a supplier of natural resources to the region and the world. Most of Alaska's privately held natural resources are owned by the aboriginal inhabitants of the state. These aboriginal inhabitants, now collectively referred to as Alaska Natives, have emerged in the last two decades as having a major international impact in mineral resource exploration, development, and production.

Jan 1, 1990