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By P Jago

KCGMÆs Fimiston Open Pit, located in the centre of the historic Golden Mile, is situated above some 3000 kilometres of old underground workings. These workings, both level and vertical, present significant safety and operational problems in the pit. One of these challenges is in safely drilling void areas so that they can be charged and blasted effectively. Current drilling practices in these areas require machines that can only drill 115 mm holes on a smaller pattern than the standard blast pattern. This results in more time and cost to both drill and charge these areas. Any other method currently available to drill out these areas involves putting operators in a potentially hazardous situation by being too close to the void area being drilled. Not effectively drilling and blasting these areas leads to hazardous situations further in the mining cycle including oversize, large toe and uncollapsed voids. Ineffective blasting also causes reductions in mining productivity and mine to mill performance. In response to these issues, KCGM has commissioned the implementation of a fully remote controlled DM45 blast hole drill rig to drill out selected void areas. The remote system, installed in conjunction with Ausdrill Ltd and GM Mining Electrics, is designed to operate similarly to a tele-remote bogging system with the operator controlling the drill rig from a separate control cabin via radio signals and video feed. This allows KCGM to drill in areas of higher risk without exposing the operators to voids. The drill rig will also be able to drill standard patterns through some specially selected void areas, reducing costs and extra time associated with drilling and charging void affected areas. The remote rig is expected to provide a number of benefits, both in the drilling process and in further downstream operations. Costs of drilling in void areas are expected to decrease with standard patterns instead of smaller patterns being drilled. Safety and operator comfort are also expected to increase through removing the operator from the pit floor. Blasting is also expected to see significant improvements through increased ease of charging void areas (because of larger holes and standard patterns), more consistent patterns resulting in less secondary blasting and toe and an overall improvement in the speed and cost of charge-up practices. This more consistent blasting will also improve shovel productivity, crusher performance and overall mine-to-mill efficiency. This paper presents an overview of the development of the remote controlled system, including modifications that have occurred since commissioning. It explains some of the problems encountered and how these have been solved. Key issues for operational success will be identified and explained with a view to making future implementations easier. Factors used to assess the performance of the remote controlled rig will also be explained in further detail and used in a preliminary assessment of the rigÆs feasibility.

Jan 1, 2003

By S Latchireddi

Close circuiting autogenous and semi-autogenous mills is anenergy efficient way of grinding and a number of operations haveutilised this in the design of their comminution circuits. Owing tothe large flow of slurry through the mill that results fromoperating this way the grates and pulp lifters have to be designedto cope. However, the literature has little or no information onhow grate and pulp lifter size and design are related to theirability to remove slurry from the mill. Over the last few years theJKMRC has been researching this area and has developedrelationships between grate/pulp lifter design and flowratecapacity. At the same time it has determined the major causes ofpulp lifter inefficiency and a solution to preventing thisinefficiency (the Twin Chamber Pulp Lifter). This paperdescribes the models that have been developed through thisprogram and uses industrial scale data to illustrate their accuracy.Results from the industrial trials of the Twin Chamber PulpLifter are also presented.

Jan 1, 2001

By M-E Boucher

While the haematite concentrates produced in Eastern Canada and the magnetite concentrates that Australia will soon be producing are different feed materials, the pellets they produce have similar physical and metallurgical properties. This paper will examine the similarities and differences in the evolution of pellet microstructure for pellets produced from magnetite and haematite. The molten slag phase generated at high temperatures has a lower melting point when in contact with magnetite compared with haematite due to the higher divalent iron content. The presence of some slag is beneficial for bonding but too much can inhibit oxidation of magnetite, although slag generation at lower temperatures reduces energy usage. In pellets produced from haematite, magnetite is generated artificially from the combustion of the carbon particles added to the pellet feed as a source of energy. Maintaining the optimum production level and mineralogy of such æsecondaryÆ magnetite, allowing for its subsequent reoxidation, is important for the quality of haematite pellets. In both magnetite and haematite pellets, balancing the slag formation and oxidation (re-oxidation for haematite pellets) of the magnetite (secondary magnetite for haematite pellets) is necessary.

Jan 1, 2007

A new gold cyanidation assay technique has been proven for a range of ores, where it has demonstrated benefits of being: ò Accurate (reduces the typical range of assay scatter almost three-fold, and avoids common fire assay interferences). ò Fast (under one hour, providing a quantum shift in space requirement and equipment utilisation each bottle roll can provide over 15 determinations per day). ò Simple (suitable for field application, no high skill or experience requirements). ò Profitable (reduced drilling, drilling time, ore misclassification and/or double handling after mining). ò Cheap (far lower cost than Fire or Aqua Regia Assays, ie LeachWELLTM costs around 10ó for a 20 g sample at 50 per cent solids, proportionately greater for larger samples eg $1 for 200 g samples which address most nugget effect problems). ò Relevant (distinguishes economic. ie cyanide-extractable gold, the only unequivocal value to use for true resource definition, mine planning and grade control). ò Robust (rough bucket chemistry of samplers does not seriously affect results). A new development is the provision of LeachWELLTM CAS, a solution, which also contains optimum cyanide and stabiliser concentrations; and offers greater: ò Safety (the dilute cyanide solutions are stabilised to avoid generating toxic HCN vapours; and present no cyanide dust or flying chips to deal with). ò Ease (a single squirt dispenses precise quantities of the entire reagent suite, avoiding multiple weighings). ò Reduction in total reagent costs. An inter-laboratory comparison on nine ore types, using two assay techniques (Fire Assay and Aqua Regia) involving 45 laboratories, has demonstrated that LeachWELLTM 60X assays for the samples tested, were equally or more reliable than typical Fire or Aqua Regia Assays. There is particularly great benefit in applying LeachWELLTM 60X assays to richer ores in comparison to Aqua Regia assays, which appear to be prone to very significant underassaying depending on individual analyst skills, and which often suffer greater nugget effects. The major impacts for heap leaching are that: ò Using the LeachWELLTM assay technique for grade control, ore of marginal grade is not accidentally discarded to waste or visa versa due to the scatter of assay data inherent in typical small charge (25 g) fire assays. ò LeachWELLTM assays very importantly report only that gold which will be recoverable in the heap, viz that which is liberated - an important factor where the coarse crush often leaves ten per cent of gold unliberated. These impacts are of particular importance for many ores (ie most of those recovered from open pit operations and at the margins of rich ore subject to slurry processing) subjected to heap leaching as the oxide zones often present major problems of nugget effects as well as mineralisation that cannot be accurately assigned through interpretation of clear structural controls.

Jan 1, 1994

By L Soares, W T. Hennies, F Fujimura

A methodology of environmental performance evaluation in mining developments is proposed, as well as guidelines and procedures for obtaining information to improve their environmental performance. Environmental performance is the results of the mining activities and their relation to environmental issues. If this evaluation is carried out on an on-going basis, it is possible to anticipate or to identify the formation and development of an environmental impact in its early stages. Evidence or trends identified by environmental evaluation provide valuable information to prevent further damage. The proposed methodology is based on the significant environmental aspects of a selected monitored job site by environmental indicators which are then compared with previously defined environmental criteria and targets or goals. The methodology procedures also take into account the environmental accounting of the investments and expenditures.

Jan 1, 2003

By Longworth C. R

This paper descrioes a case history of a coal mine which developed un'tahle roof conditions due to mass sliding of the overburden strata on a claystone band within the coal seam. The sliding is believed to have been initiated by stress relief associated with the removal of overburden alongside the entry portal of the underground workings. Once in motion, the roof block was kept moving by bulking due to roof collapse in the normal underground goafing operations. Control measures in the form of an earth and rockfill buttress against the entry portal and a sequential mining plan to create goaf areas alongside the entry portal have been initiated to attempt to limit movement. The operation has been continually monitored and a gradually decreasing pattern of movement is being re, orded.

Jan 1, 1981

By M Cooksey, C Goodes, G Wellwood

Light metals have great potential for application in the automotive and aerospace industries because of their excellent physical properties. The usage of aluminium, titanium and magnesium is limited by relatively high costs of production, associated energy costs and large ecological footprint. In the case of aluminium, significant improvement to the Hall-HTroult process is still achievable through advances in cell design, materials and process control. Alternative production processes, including carbothermic reduction and low temperature routes are also possible. Magnesium and titanium production are currently dominated by batch metallothermic processes and new process routes are required to develop these industries. Research at CSIRO, through the Light Metals Flagship, is currently focused on step change improvements in the production of light metals, aimed at lowering energy usage, increasing productivity and reducing the overall environmental impact. In this paper, the overall status of the existing technologies will be described, highlighting areas that are being developed around the world and at CSIRO.

Jan 1, 2006

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 J Krahn

In designing climate exposed soil structures such as caps and covers over mine waste it is necessary to include the wetting and drying influences of the local climate in order to accurately predict the net water, vapour and oxygen fluxes across the ground surface and through the base of the covers. The most advanced evaporative flux modelling tools currently available to practitioners have been limited to rigorous one-dimensional models (ie SoilCover) or semi-empirical two-dimensional models (ie Hydrus-2D). It is common practice to use the rigorous one-dimensional evaporative flux model results to develop a surface boundary function that can then be applied within a saturated/unsaturated two-dimensional model. However, this is not an ideal situation and results in a further approximation of the real system being modelled. This paper will highlight the use of a new modelling tool, VADOSE/W, which brings existing, rigorously formulated evaporative flux theory into the familiar setting of a two-dimensional model. The model is enhanced for simultaneous two-dimensional oxygen gas transport analysis, which has direct application in the mine waste industry. A key focus of the paper will be addressing the limitations of one-dimensional analysis for cover systems on sloping and hummocky terrain.

Jan 1, 2003

By Meunier G, Davis J, Koperski G

The dry processing of mineral sands concentrates can result in the generation of significant amounts of airborne dust. The radioactive component of this dust has implications within the context of work environment health codes. The last four years have seen considerable investment in dry plant equipment enclosure and dust extraction systems, with resultant reductions in plant ambient dust levels. Simultaneously, an industry wide program was started to examine the origin, nature, mineralogy and radioactivity of the airborne dust. The major findings of this study have been: ò confirmation that monazite was the only significant source of dust radioactivity. ò recognition of two sources of dust: - agglomerates of finely divided ilmenite-rutile alteration products, which are formed by the removal of surface coatings and particles. - abraded mineral fragments, which reflect the mineralogy of the parent particles.

Jan 1, 1991

The geology and mineral deposits of the West Pilbara Goldfield are described and comparison is made with the Pilbara Goldfield,, In the West Pilbai'a Goldfield two adjacent environments are represented by a predominantly clastic succession and a predominantly volcanic succession. These two successions are lateral equivalents and lithologically they are similar to the classical successions at Warrdiwdbna and Mosquito Creek. How- ever, no evidence of a significant erosional break has been found. It is suggested that the Archaean rocks of: the Pilbara Block represent a single geosynclinal cycle, which culminated in orogenesis, within which-local disconformities have been developed in various places: and that the sub-Mosquito; Creek unconformity at Eastern Creek may be the most widespread of these disconformities, Widespread evidence of'preconsolidation movement, aid the intrusion of igneous rock into. unconsolidated sediment, suggest that tectonism and igneous activity began at a very early stage, This was localised along lines of fracture in an unidentified basement.,.Moveme.nt was primarily vertical and persisted into the older Proterozoic, The sediments were enriched in metal by vulcanicity, chemical sedimentation, and possibly detrit`1' contribution. Diagenesis and metamorphism caused the remobòliyation of the metallic constituents of igneous and sedimentary, rocks which were then localised-in loci of dislocation-formed both before and after consolidation.,.. . . , . .

Jan 1, 1964

Lake Kopiago is located some 71km northwest of Tari in the Southern Highlands Province and lies on the northern edge of the Papuan Fold Belt. The area is underlain by middle Miocene carbonate and fine grained clastic sediments intruded by late Miocene hornblende gabbros.Two mineral deposits occur to the south of Lake Kopiago. These are the Bisamu gold prospect and the Wunaki zinc-lead gossan.The Bisamu deposit consists of a calcic skarn assemblage which is geochemically anomalous in gold, silver, copper, zinc, cobalt, bismuth and tellurium. The prograde mineral assemblage includes garnet, clino-pyroxene and epidote whereas the retrograde assemblage includes epidote, quartz, actinolite and chlorite. Pyrrhotite is the dominant sulphide with minor pyrite and marcasite and trace chalcopyrite and sphalerite. Minor magnetite is also present. The Bisamu skarn shows many of the features typical of gold-skarn type mineral-isation.

Jan 1, 1994

The Lake Rotokaua sulphur deposit, near Taupo, New Zealand, is a lacustrine sedimentary ore body, 220 acres in area and from 7 ft to 96 ft thick, containing, within the area drilled to date, some 20 million long tons of ore averaging 25% elemental sulphur in unconsolidated tuffaceous diatomaceous clay, overlain by about 120 ft of pumice sand and by the shallow Lake Rotokaua. An additional amount of perhaps 4 million tons of sulphur is regarded as probable in the area remaining to be drilled. Current economic studies cover the problems of mining an unconsolidated water-saturated formation with some residual thermal activity nearby; conservation and restoration after mining in a scenic recreation area; beneficiation of the ore and extraction of high- purity sulphur, principally for fertilizer manufacture. The deposit has additional importance as a pointer to possible further discoveries in the Thermal Region.\

Jan 1, 1971

It is now 32 years since Walsh's classic publication (1) heralded the beginning of atomic absorption spectrophotometry (AA) as we know it today. During this time, AA has developed into the most widely used analytical techniques for the determination of the metallic elements. The years have seen progressive changes in instrumentation so that today it is a highly sophisticated technique. One area of development in AA that is experiencing renewed attention is in the area of electrothermal excitation. In this technique a flame is not used by the analyte solution is atomised by an electrically heated graphite furnace. For a large number of elements the graphite furnace atomic absorption spectrophotometer (GFAA) is considerably more sensitive than flame work. It is common to be able to detect concentrations one hundred times smaller than those possible by flame. Today's geochemists are finding that they can gain valuable information out of very low limits of detection. Electrothermal atomic absorption spectrophotometry (or GFAA) allows for low limits of detection and can be seen to be a valuable aid to geochemical prospecting Analysis.

Jan 1, 1987

Detailed observations were made for two existing continuous miner and shuttlecar systems. A simple model for the shift average cycle consisted of three time components - delays, mining and transport. Cycle improvement and productivity improvement factors are derived and used to predict the theoretical improvement which the observed cycles could achieve. Various strategies of action ranging from short-term optimisation through to long-term planning for continuous haulage systems are evaluated. High potential for improvement is shown for a wide range of operating conditions. An overview is presented for systems, currently available or under active development, which can accept coal directly from continuous miners and offer continuous haulage to the surface. Systems are broadly classified as mechanical-roof mounted, mechanical-floor mounted and hydraulic transportation.

Jan 1, 1982

Rock bolting has become the most important method of ground support at Mount Isa. Various types of rock bolts are used to suit the different applications and requirements. To apply rock bolting techniques satisfactorily, it is necessary to have some knowledge of the nature of the rock, the type of rock failure, any stress redistribution which may occur during the intended life of the rock bolt and the time for which ground support is required. At Mount Isa there are a number of dif- ferent applications of rock bolts for ground support, and some trends in rock bolting techniques.

Jan 1, 1971

By Neto J. A N

Usually there are organisational interfaces between each stage - companies or departments. Each organisation will have different ideas about "optimum" operation. These ideas will be driven by how the performance of each is measured ' and rewarded. Therefore it is important to set up data acquisition processes with respect to maximisation of overall profitability and resource utilisation. In the simplest case - if the miners are paid on tonnes and the concentrator has severe grade penalties on concentrates, then there is the possibility of a conflict of interest over metal Balance.

Jan 1, 1991

The production of synthetic crude oil requires a suitable coal or a coal extract modified by hydrogenation for pyrolysis. Existing classifications are broadly based on historical and current needs. One, Seyler's, is based on a visual display which can be used to present petrographic bounds. The analysis of the coal extracts from solvent hydrogen-donor testing allows an experimental limit to be described and a plant limit to be indicated. Australian black coals are discussed within these petrographic and plant bounds and their limitations as a feed for the production of synthetic crude presented. Potential uses for the aromatic liquid products are suggested. The application of the diagram as a screening procedure for sub-hydrous coals is described.

Jan 1, 1975

While, in the past, a great deal of attention has been focussed on technical issues and the performance of explosives in rock, the explosive user, an essential link in the chain, has often been neglected. In the mining industry, too often, the benefits of excellent technical work have been degraded over time due to the lack of definitive and documented control. Using the principles of quality management a quality training system was developed and implemented for management of explosives use at Gunpowder Copper Ltd (GCL). This paper describes the structure of the system, its development and implementation, and contains practical advice and information for managers responsible for blasting and charge crews. The paper is in four parts: I Quality systems. A brief overview of the relevant aspects of total quality management that apply to explosives use. The requirements for documentation, management and auditing are explored. 2. Training for competency. The five essential elements of Competency Board Training (CBT) are examined, including auditing. 3. The Gunpowder Copper system. Implementation of the complete training system. Documentation and its control, auditing, instructions for operators, management responsibility and means of obtaining operator ownership are amongst the issues raised. Reporting requirements are the means to effectively manage change are described. 4. Summary. The paper concludes with the tangible benefits seen by Gunpowder Copper through the adoption of a quality training System.

Jan 1, 1995

By Chitombo GP

The proposed guidelines on vibration limits that have been circulated by the Australian Environmental Council, demonstrate the need for an extensive data collection and evaluation program to avoid the enacting of abritrary and costly legislation. The operational or practical influence of blast design and overall economic implications of legislation which further reduces permissible levels of ground vibration are discussed. In a typical blasting operation, blast sizes could become smaller and blasting correspondingly more frequent to meet pro- duction demands. Blasthole diameters and charge lengths could be reduced, increasing drilling costs and associated labour costs. Blast size however, is frequently controlled by factors associated with machinery, grade control, pit control, stope size, production contract levels and other factors which cannot be readily changed for operating mines. Blasthole diameters are frequently deter- mined by existing drilling equipment, length of holes (depth of ore or stope size), geological structure and other factors which are not easily changeable. Typical large scale open stoping and strip mining opera- tions are analysed as case studies. The effects of extreme leg- islative limits and the corresponding operational changes with respect to variations in production costs are discussed.

Jan 1, 1987