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This case study describes various aspects of establishing a laboratory facility for testing chemically-cemented fill materials. The applicability of data obtained from such a facility related to mine conditions depends on many factors: kind of data, type of testing facility, sample parameters (composition, geometry, size, etc.). The equipment employed must be adaptable, to accommodate variations in sample size and properties. The design, construction and operation of the testing facility is described, and its application to fill samples prepared from sulphides and oxides both chemically and naturally cemented. The present system was selected following an extensive study of equipment available for testing materials in the fields of rock mechanics and construction materials. The strength testing' facility incorporates Linear Variable Differential Transformers for monitoring both lateral and axial displacements during sample compression. The output from these and from other related instrumentation can be recorded or fed direct to a computer, enabling stress-strain data to be printed out while the test is in progress. Also described are controlled environment curing facilities which allow samples to be cured or weathered under different temperature or humidity conditions to simulate long-term ageing and in place conditions.

Jan 1, 1973

The design and selection of components for belt conveyors is a well known procedure and many handbooks, catalogues and design manuals offer a wide range of detailed information which can be applied to most of the known conveyor problems. The aim of this paper, however, is to investigate the various methods of conveyor drive configurations, and incorporate the latest technical achievements in the control systems, particularly for high capacity conveyor systems carrying ore from pit to processing plants where the lowest maintenance, operating and initial costs are of major importance. Past experience has proven that multi pulley drives can reduce initial capital cost of a conveyor; this leads to the need for better torque control during startup, running, stopping and load sharing. Many methods of torque control are available and have been used in the past. All types have their advantages and disadvantages and must be considered when designing a conveyor or conveyor system. However the recently developed solid state electronic soft start controls utilising AC squirrel cage induction motors are gaining acceptance, especially for a conveyor system where the same control and logic system can be used to transmit startup commands to more than one

Jan 1, 1978

The copper deposits at Pernatty Lagoon are predominately djurleite-digenite bodies beneath the permanent water table, and chrysocolla-atacamite-malachite above the permanent water table. The minerals havebeen deposited as sheets, lobes, and pods in zones suggestive of permeability channels or permeability basius with respect to groundwater circulation.Pyrite is deposited in the form of framboids, which reflects its biogenic origin. Copper-iron sulphides deposit by replacement of pre-existent pyrite, and rarely by direct deposition. The latter mode of formation results in complex crustification bandings of chalcopyrite, bornite, sulphur rich bornites, digenite, and blue remaining covellites. The copper-iron sulphides appear to reequilibrate under constrained oxidation, resulting in an iron depletion and associated copper enrichment, the final product of which is a djurleite-digenite assemblage and associated with goethite. Where copper mineralization/ host rock relationships have rendered the rocks entirely impermeable to post ore groundwater movement, then the copper-iron sulphides are preserved as the ore assemblages.Minor and trace minerals observed include sphalerite, carrollite, galena, wittichenite, and possibly tetrahedrite in the primary ores. In the oxidized ores cllprite, tenorite, and trace brochantite have been found.

Jan 1, 1976

Economic and technical reasons forced the mining industry all over the world to increase the unit size of mineral processing equipment. in large flotation cells, this development leads to problems in areas of air dispersion and keeping solids in suspension. Outokumpu, an operating mining company, designed and developed a mixing mechanism for large flotation cells at its own concentrators and also studied problems related to tank design. Ideal conditions for flotation can only be achieved if the flow pattern created by the mixing mechanism fits well into the tank configuration and the risk of short circuiting is minimized. In large deep flotation cells, four different zones can be found which improve the behaviour of large cells when compared to small cells. Selectivity is increased and in some cases final concentrate grades can be produced from the rougher cell. The largest units have also been used as final cleaners in some installations. When modernizing old plants by installing fewer larger flotation cells, immediate and substantial savings in power consumption are achieved. Additional power savings are made in pumping costs because of simpler circuit design and decreased circulating loads

Jan 1, 1978

The exploration and mining risks are investigated and compared to the risks of smelting, secondary processing and other normal industrial activities. This study concentrates on the risk before, or at the investment decision. Internal and external risks are distinguished. Internal risks are the risks inherent in every engineering design and common to all projects. The main external risks are the financial risk, changes in prices, location problems and geological factors. Financial risks concern every capital-intensive and export-oriented project and cannot be considered as typical mining risks. Changes in prices, i.e. the market risk, concern every industry using raw materials, but the market risk is especially accentuated in the mining industry. Problems of location and infrastructure are normally more significant in mining than in other projects, and geological risks are unique to mining. All these risks associated with mining projects combine to form a risk at least twice as high as that for other normal industrial activities. Within the range of profitability of mines, which on average is the same as in the manufacturing industry, only a few highly profitable mines exist. These few mines are the sole reward for the high risks taken.

Jan 1, 1986

The 250 metric tonnes of gold and 360 000 metric tonnes of copper recovered from the Mt Morgan Mine in Central Queensland justify its fame. The mine ceased operation before the advent of three-dimensional computer graphical modelling of orebodies became common practice in mine planning. The Mount Morgan Mine records however remain and are the database for this study. The Mount Morgan project takes ore deposit modelling one step further by examining the relationship between grade distribution within the orebody and key geological features, as a tool for exploration and development.The Mount Morgan gold and copper mineralisation is shown to be strongly lognormally distributed. The deposit has been split into three areas, using geological boundaries, each with different geostatistical characteristics. Important features include: the spatial relationship of near-vertical, high grade shoots with a ring dyke thought to be related to the North Dyke; separation of the high grade eastern stopes from the others along the Andesite Dyke; and lack of concentrated mineralisation along the Slide Fault.Recognition of these features is useful to those currently exploring the Mount Morgan district for similar style deposits, by stressing the importance, or lack thereof, of the geological features.

Jan 1, 1993

By A J. MacDonald, M P. Raffield

The South Deep massive orebody consists of 20 to 30 m of payable conglomerates ranging in dip from 11¦ to 20¦ and at depths of between 2400 m and 3400 m. The mine design process selected a mining method with a proven record of application that could be adapted to overcome the inherent difficulties associated with the depth, thickness and structural influences of the South Deep orebody. A modified cut and fill mining method provides a concentrated and highly flexible method of extraction. An integrated destressing cut will enable the modification of the stress environment such that it is suitable for massive mining operations. The choice of backfill type and stoping width in the destressing cut ultimately determines the characteristics of the stress modification and, as such, is critical to the success of the cut and fill operation. This paper discusses the decision process undertaken to determine the optimum backfill type and stoping width combination in terms of, conditions in the destressing cut faces and in the massive mining environment. Numerical modelling has been extensively used to analyse various scenarios to aid in the decision process.

Jan 1, 1998

By Spark R. F

The copper deposits at Pernatty Lagoon are predominately djurleite-digenite bodies beneath the permanent water table, and chrysocolla-atacamite-malachite above the permanent water table. The minerals havebeen deposited as sheets, lobes, and pods in zones suggestive of permeability channels or permeability basius with respect to groundwater circulation.Pyrite is deposited in the form of framboids, which reflects its biogenic origin. Copper-iron sulphides deposit by replacement of pre-existent pyrite, and rarely by direct deposition. The latter mode of formation results in complex crustification bandings of chalcopyrite, bornite, sulphur rich bornites, digenite, and blue remaining covellites. The copper-iron sulphides appear to reequilibrate under constrained oxidation, resulting in an iron depletion and associated copper enrichment, the final product of which is a djurleite-digenite assemblage and associated with goethite. Where copper mineralization/ host rock relationships have rendered the rocks entirely impermeable to post ore groundwater movement, then the copper-iron sulphides are preserved as the ore assemblages.Minor and trace minerals observed include sphalerite, carrollite, galena, wittichenite, and possibly tetrahedrite in the primary ores. In the oxidized ores cllprite, tenorite, and trace brochantite have been found.

Jan 1, 1976

By S C. Dominy

A high nugget effect and the presence of coarse gold characterises many vein-gold deposits. The effective sampling of these deposits is often difficult because of the relatively low concentrations involved and erratic nature of the gold. Geological complexity often compounds this effect. Underground development, in-fill drilling and bulk sampling/trial mining are often required to delineate Ore Reserves. Winzing is an historical technique that was used to gather geological and sampling data during underground exploration. It permits access to the mineralised structure below the current datum to help determine viability. Winzing has always been considered an arduous and dangerous task. Modern technology has led to the development of the Mobile Supersucker, essentially a giant vacuum cleaner. This system permits safe and efficient winzing activities, and allows the collection of bulk samples for grade estimation. Bulk samples from horizontal development have long been collected to help define mineable grade. However, when defining blocks below current development, there has been over-reliance on ineffective æsmall sampleÆ drill data. The Mobile Supersucker permits safe and cost-effective development of winzes and off-winze sublevels.

Jan 1, 2003

By Collins D. N

The Olympic Dam Copper Smelter Acid Plant is a hybrid plant capable of producing sulphuric acid from either sulphur burning, metallurgical gases or a combination of both. Commissioning of the Acid Plant on sulphur burning commenced in early April 1988 and commissioning on combined sulphur burning and metallurgical gas commenced in August 1988. During commissioning on sulphur burning a number of acid spills occurred due to balancing of tower flows and control of acid dilution. A number of other significant problems were encountered including failure of boiler gaskets, failure of strong acid pumps seals, the fracture of the teflon dilution water injector and the subsequent failing of the acid circulation pump, tank steel failures and various instrumentation problems. The Commissioning of the Acid Plant on metallurgical gases commenced in August and with the exception of the production of oleum in the boiler economizer was relatively trouble free. Oxygen Plant commissioning commenced in May 1988 and was without significant incident. An outline of the basic equipment for the Acid Plant and Oxygen Plant is presented together with aspects associated with the commisisoning of both plants.

Jan 1, 1989

By Baker EM

The Kidston orebody is a kilometre diameter breccia pipe of Permo-Carboniferous age' assoc- iated with rhyolitic dykes and hosted by Proterozoic granodiorite and metamorphic rocks. Mineralization and alteration are associated spatially and temporally with brecciation and rhyolite intrusion. Three stages of alteration have been recognized: pre-brecciation, and early and late stage post-brecciation. Gold is known to be particularly associated with late stage post-brecciation cavity infill and sheeted veins. Fluid inclusion and stable isotope results show the importance of moderate-high temperat- ure, saline, magmatic fluids in the early stage mineralization and in the brecciation of the pipe. Later periods of alteration, accompanied by gold deposition, are associated with fluids only slightly depleted in 180 relative to mag- matic waters, unlike the strongly 180-depleted meteoric water typically found in hydrothermal Permian and Carboniferous deposits of eastern Australia. The 5180 values and low salinities in fluid inclusions suggest the fluid may have formed from vapour condensation from a magmatic fluid. Fluid inclusion data and alteration assemblages define the prevailing chemical conditions. Gold transport under these, conditions would have been primarily as a bisulfide complex.

Jan 1, 1987

In the time since the first trials in the mid-1980s, the Rare-Earth Magnetic Separators (REMS) are presently (year 2001) found in many heavy mineral sands plants around the world. Both the roll and the drum type are used from ilmenite concentration to cleaning high-purity zircon products. Chromium-bearing materials are removed from ilmenite more selectively than with electromagnetic separators. Greater flexibility and higher grades in ilmenite circuits are achieved. Cleaner rutile and zircon products, even with respect to levels of radioactive materials, are the result of superior magnetic force optimisation. Tailings from roaster plants can be reprocessed effectively, which is encouraging some operators to look at replacing old equipment in order to process roasted material plant feed or implement use of the new generation drum separators in new plants. Wet separation of ilmenite by using powerful wet REMS drum separators is now a possibility. This may be an alternative to at least a portion of the Wet High-Intensity Magnetic Separators (WHIMS) process for ilmenite preconcentration. A dry plant process flowsheet can often be modified by displacing a portion of high-tension separators with new high-temperature tolerant REMS.

Jan 1, 2001

To meet the objectives of sustainable development, mining projects must be executed with minimal environmental risks and impacts. To allow proper actions to be taken, it is helpful if the environmental challenges associated with a mine development project can be predicted early during exploration activities. Signs of impending environmental problems like acid rock drainage and metal leaching are often revealed in the occurrence of natural acid drainage, formation of efflorescent salts and their associated ecological effects. Other subtle clues can be deduced from anomalous geochemistry, detailed textural features of mixed sulfide assemblages and miscellaneous environmental data sets covering the target areas of exploration. A more practical tool, however, is the development of comprehensive environmental ore deposit models containing relevant information on ore genesis, applicable mining, processing and waste management options and their environmental implications according to deposit type. Not only will such models facilitate communications among independent groups of personnel involved in a mining project to come up with schemes to ensure better environmental performance of the overall project, they will also facilitate decision-making if a mine development project should be pursued further or valuable resources be redirected to other more favourable targets.

Jan 1, 2003

Uranium minerals were found in Australia as early as 1869, but it was not until the 1940's that a search specifically for uranium was begun. Instrument types and techniques used in early exploration are still used today, but have been developed into more sophisticated and portable types. Recent improvements in exploration have been the introduction of the gamma ray spectrometer, radon sampling and geochemical surveys. The environments of presently defined uranium deposits are predominantly sedimentary. Known deposits in igneous environments are usually small. The size of targets which are likely to provide economic deposits is of the order of 10,000 tons U308, producible at a cost of less than $10 per pound. Such targets are most likely to be in Precambrian sediments or in granitic masses. Recent exploration in Australia has included investigation of Precambrian sediments, Precambrian and Palaeozoic granites, Mesozoic and Tertiary sediments, Precambrian volcanic rocks and brecciated masses of unknown age. The origin and method of emplacement of uranium in these environments is not well known but there are indications that syngenetic sedimentary processes are important, and volcanic rocks may make a major contribution to the supply of uranium.

Jan 1, 1970

By D F. Akhmetov, M Yasuike, M Komazaki, Y Kawa

Remote monitoring of geological situation at distant regions with complicated relief, including reliable detection of the rock falls and estimation of the scale of accidents, is of great importance for practical needs. In the paper, vibration data, caused by fall of sample objects and registered by cable sensors, are processed and analysed in order to construct some measure for the indirect evaluation of weight of fallen objects. Nonlinear models, which based on artificial neural networks (ANN), are proposed for the signal presentation. To improve and simplify the learning and classification abilities of the whole system, the aggregative learning method (ALM) is implemented. ALM features relatively low memory and computational resources needed for the procedure realisation, especially for data classification (recall) stage, in compare to conventional methods. The validity and efficiency of the proposed approach are tested through its application for rock fall detection and weight evaluation system using cable sensors and mobile communication network. Classification abilities of the proposed approach are shown useful for estimation of the fallen object weight. Characterised with high computational efficiency and simple decisionmaking procedure, the derived method can be useful for simple and reliable real-time monitoring system design.

Jan 1, 2003

Patterns of successful metallic mineral discoveries in Australia are analysed for the last three decades. A trend towards more discoveries of poorly expressed and blind ore- bodies is evident and can be expected to continue. Discoveries using traditional and conceptual geological techniques have proportionally declined but are expected to continue at a significant level for a decade or so. Improvements in the quality and numbers of geological exploration models and in the quality of available basic geoscience data have aided successful discovery in recent years. Although some orebodies for the Year 2001 have already been found maintenance of a strong mineral inventory demands that more and better geological models are applied. Empirical models need to be improved by critical multi- disciplinary integrated studies of mineral occurrence at all scales. New models can and will be developed by various means. If application of these models is made with all the innovation, initiative and unorthodoxy that can be mustered then new discoveries will result. Greater attention to the surface expression of orebodies will also lead to new discoveries. Review and follow-up of old data in the light of new concepts will provide yet another discovery route.

Jan 1, 1981

Human creativity springs from the natural desire of mankind to know and its capability to learn. Explorers and discoverers possess these features in a high degree. They are driven by an unrelenting curiosity to go beyond the boundaries of the known, to explore into the nature of things, to reveal connections between ideas, facts, conceptions, to view things from new angles, to change perceptions. A well-known fact about the construction industry - and underground construction in particular - is that all projects are unique. The degree of complexity due to the intertwining of the variety of project-related parameters is higher than in many other industries, thus forcing contractors as well as suppliers to be truly adaptable and flexible. The enormous advantages of shotcrete as a construction and rock support process and the improvement of materials, equipment and application know-how have made it a very important and necessary tool for modern underground construction works. The development of modem wet shotcreting in particular has enlarged the field of underground construction work. Projects that were impossible to be realised, have now become practicable. Subsurface structures can be placed where they are needed, without regards as to rock and soil conditions.

Jan 1, 1995

By Elber L, Whiten WJ, Cunningham KD, King GL, Bailey CW, Clay PA

The Savage River Mines concentrator treats magnetite ore at about 300 tonne/h, and produces feed for a pelletising plant. The plant incorporates two parallel grinding lines, each consisting of an autogenous mill, in closed circuit with a screen, a rougher mag- netic separator, a ball mill in closed circuit with parallel cyclones, and a finisher magnetic separator. Significant fluctuations in ore grade and grindability make it difficult to maintain pro- duct size in the narrow range desired, and to achieve maximum possible throughput at the same time, using the present largely manual control system. The present paper describes the develop- ment of a control system based on a mini- computer. It has been possible to implement a scheme of on-line estimation of product size which is sufficiently accurate for use in an automatic control system. The size estimation is essentially derived in terms of plant variables which control the ball mill cyclone cut size. Three control functions have so far been implemented and tested. These are control of the feed rate to the autogenous mill, control of water addition to the autogenous mill, and control of the ball mill sump level.

Jan 1, 1978

The limitations of the conventional practices, and their effects, in prospecting for and in the evaluation of alluvial gold deposits are briefly reviewed. Geophysical prospecting methods have demonstrated their complementary role in the delineation of deposits by reducing the number of boreholes which are primarily of a 'probing' type. Larger diameter boreholes, although more expensive on a linear basis, are much cheaper on a volume recovered basis. The need to have sufficient volume as well as number of samples is stressed. Classical statistical methods are not appropriate for such deposits as there is sufficient structure, or spatial correlation, to require the application of geostatistics. Quite reliable semi-variograms, but not in all cases, of the spherical scheme have been obtained. Subsequent kriging has, to date, been confined to unworked deposits: retrospective estimates to compare to production have not therefore been produced. However, the technique shows promise but indicates a considerably greater borehole density (of the conventional diameter) may be necessary to produce confident estimates. Used in conjunction with larger diameter boreholes, a lesser borehole density may be sufficient, through radical reductions of the sampling error.

Jan 1, 1977

The word "optimization", refers to the search of an economic optimum, or, more precisely, to the choice of technical parameters which will define the more profitable mining project, knowing the values of the economic parameters. In fact, there is no direct way to perform this optimization, because the extremely large number of technical factors involved, from the type of working and its selectivity to the characteristics of the mill and its flexibility, makes it impossible to make a comprehensive survey of all possible projects. Beside, it would be meaningless to engage in such a task as the deposits themselves are not really known, but only estimated, with sometimes a high level of imprecision. Not to mention the numerical instability which would affect such a computation! In addition, the "best" project is not necessarily the one which strictly maximizes a given profit formula. There also exist human factors which have to be complied with, when choosing the cutoff grades for instance. Finally, there are other non-numerical factors which interfere with the choice between several projects: the shape of the bottom of a pit of the layout of the access road for instance.

Jan 1, 1986