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By Hiddlestone D. C

Effective exploration, testing and analysis is essential for good process design and optimisation of coal preparation plants. Coal processing relies on the sizing and washability characteristics of the particular coal to define the most cost effective design to meet the market requirements. Flowsheet development and equipment selection is dependent on the natural quality characteristics of the coal, its physical properties and the value of the final product in its market. The methodology of process selection and the key elements in design are discussed. Coal is consumed in two general markets: ò steaming coal - both domestic and export, and ò metallurgical coal. This paper discusses the typical economic analysis required to evaluate the potential for, and cost benefit of, providing the flexibility to switch coals between markets. A case study illustrates the methodology of process selection in a typical high value metallurgical coal.

Jan 1, 1997

The paper describes the geotechnical as- pects of design and construction of two 12 m diameter concrete lined tunnels from the start of design to completion of construction. Prob- lems occurred due to delay in supply of essen- tial rock support materials from overseas and alternative methods using locally available materials were developed. Several major rock- falls and rock movements occurred and remedial measures are outlined.

Jan 1, 1981

By J McQuie

The concentrator at WMCÆs Leinster Nickel Operation has operated with flash flotation in the grinding circuit since the early 1990s. There has always been a positive correlation between flash flotation Ni recovery and overall Ni recovery û however this relationship could be explained by differences in the ore, rather than by the action of the Flash flotation cell in reducing overgrinding of Ni. In July 2003, refurbishment within the plant made it necessary to operate the concentrator for a period with the flash flotation cells off. The resulting data set provided evidence that flash flotation in the grinding circuit changes the size distribution of Ni to reduce the amount of slow-floating fine (-7 ¦m) Ni produced. Ni recoveries in the finer size fractions were similar with flash flotation on or off û but because less fine Ni is produced when the flash flotation cells are operated, overall Ni recovery improved.

Jan 1, 2005

A system for rapid on-line determination of weight percentage coal in slurry and weight percentage ash in coal has been developed at the Julius Kruttschnitt Mineral Research Centre, University of Queensland. The gauging system is suitable for use with coal flotation slurries or slurries having a maximum particle size of about 1 millimeter. The system is based upon measurement of gamma ray transmission; radioisotope sources emitting photons of two widely different energies are employed. The inaccuracies of measurement that would normally result from variable amounts of air entrained in the slurry are substantially reduced by pressurising the slurry to approximately 2MPa (300 psi) using a Mono pump. The equipment can be used to make measurements on more than one slurry stream by pumping streams sequent- ially. The system is being tested at the Peak Downs Mine of the Utah Development Company in Central Queensland. This paper describes the theoretical principles of the gauge design, the experience gained to date in the commissioning of the equipment, including the installation of a PDP 11/03 computer, and the progress made in developing satisfactory interpretations of the gauge count-rate output.

Jan 1, 1978

By Roe P, Lowell A

This paper outlines software development and design work carried out by Mincom Pty Ltd in collaboration with Capricorn Coal Management (CAPCOAL) for computer based design of rehabilitated strip mine landforms at German Creek Mine. Current developments and future application areas for this software are also discussed in relation to other mines in Central Queensland. The development program was initiated in response to statutory requirements placed on mining companies in 1990 to produce a five year Plan of Operations which was to include a contour plan of the final rehabilitated mine landform at the end of the five year planning period. This plan was to be submitted to the Department of Resource Industries (DRI) by 1 December 1990. Due to the limited time given to prepare the plan, a work program was formulated in collaboration with Mincom Pty Ltd to develop suitable software to carry out the design work and provide the required plans and quantities. The software had to include computer based methods to allow design of the proposed landform in line with the rehabilitation strategy adopted by CAPCOAL at the time.

Jan 1, 1991

In the hard rocks of the Nordic countries of Norway, Sweden and Finland underground works have a long tradition. Today the subsurface has been taken into use for a wide variety of purposes. In this paper only the more uncon- ventional examples are described such as caverns for drinking water, sand bunkers, molasses silos, wine and liquor stores, cold stores, heat storage, waste disposal and state archives. The particular use of unlined high pressure tunnels and socalled air-cushions for hydropower schemes is discussed. The dual use of subsurface air-raid shelters for sports activities seems to be a special Nordic tradition. Some cost figures are given and the advantages of using the underground is Discussed.

Jan 1, 1987

By Stanton G

The Department of Mapping and Surveying (DMS), the Australian Key Centre in Land Information Studies (AKCLIS), the Department of Industry Development (DID) and the State Government Computer Centre (SGCC) are testing a regional information network in northern Queensland. Several study sites have been chosen by different groups of participants. The members of each common-interest group share their data for the site. They can also access datasets supplied by other organisations that are not directly involved in the particular study being undertaken. The participants include state government departments, local authorities, fed- eral organisations and the private sector. The participants communicate with computer systems in Brisbane via Q-Net. Q-Net is a pilot State government tele- communications network, established by the Department of Industry Development. Q-Net uses the communications sat- ellite AUSSAT 1 as the primary instrument of data transfer. The Q-Net network is a star system, with a Master Earth Station in Brisbane acting as a hub for radial earth stations, located throughout Queensland.

Jan 1, 1987

By Kametani H

Since pyrite is a semiconductor, the relationship between the leaching rate and the semiconducting properties is of interest. In order to investigate this relationship, a pyrite concentrate (95% FeS2) was oxidized at 90¦C (363 K) in an acid solution containing 100 g/dm3 H2SO4 and 1.0 to 25.1 g/dm3 total Fe. The suspension potential (Pt vs. SCE) was maintained at the desired values, within the range 0.40 to 0.70 V, by controlled additions of a KMn04 solution during leaching. The results were analyzed using a simplified kinetic expression. The rate constant was independent of the Fe concentration, while it increased with suspension potential. Partly oxidized samples were then prepared at varying fractions of reaction. After removing the elemental sulphur formed, they underwent thermoelectric power measurements using a packed bed lying in a temperature gradient. The value of thermo- electric power increased from about 0 to 30 pV/K in the early stages of oxidation. The results obtained are compared with those for chalco- pyrite reported in a previous paper.

Jan 1, 1987

By Bailey S, Avraamides J

Laboratory-scale experiments were conducted in a mechanically stirred aeration vessel to determine the rusting abilities of aerated water in the presence of various catalysts compared to the industrially used ammonium chloride. The catalysts used were tartaric acid and citric acid, firstly by themselves, and then in later experiments mixed with ammonium chloride. From these experiments it was found that leaching of iron from reduced ilmenite in the presence of either tartaric acid or its sodium salt was much slower than in the presence of ammonium chloride. Citric acid or its sodium salt also give a slower rate of leaching than the ammonium chloride system, but citric acid and its sodium salt mixed in equal proportions produced a rate of leaching approximately twice as fast as the standard ammonium chloride system. When tartaric acid was mixed with ammonium chloride the leaching rate was found to be equivalent to the leaching rate of the same amount of ammonium chloride alone, thus indicating that tartaric acid made no contribution to the leaching in this svstem_

Jan 1, 1996

By Palmer G, Dennis R, Clark A

The Ravenswood Mine in North Queensland is the first gold mine developed by Carpentaria Gold Pty Ltd, a wholly owned subsidiary of MIM Holdings Ltd. Carpentaria Exploration Pty Ltd began exploration at Ravenswood in 1978. However initial exploration of the main gold producing area (Buck Reef East) commenced in March 1987 when exploration rights to four key leases were secured. A rapid, co-ordinated exploration and development program produced gold from a heap leach operation nine months after the first costeans were dug at Buck Reef East. To treat higher grade ore found at depth in the Buck Reef East pit and the metallurgically more difficult Buck Reef West ore, a carbon in pulp plant was commissioned in May 1988. The mine is currently producing at a rate of approximately 40 000 ounces of gold per year. Ore at Ravenswood is hosted by hydrothermally altered diorites and tonalites of the Ravenswood Granodiorite complex. Alteration is controlled by planes of permeability formed by joints, shear zones and dilational breccias. The complex orebody geometry resulting from these controls required very detailed surface and drill exploration for adequate definition. Carpentaria's need for early cash flow meant that economic, mining and metallurgical considerations governed choices of exploration techniques, program timing, material and data collected. The initial reserve of 1.1 mt @ 2.87 g/t Au was defined by sectional polygonal methods. Grade control is based on geologic mapping and blast hole or channel sample assays. Ore is batched through the crusher and sampled to monitor grade control and mining performance. Minimal dilution has occurred. Gold content is greater than predicted by the reserve. Sprinkling of heaps commenced in November 1987. Changes have been made to the pad design and to the method of heap construction. Heap leach ore is treated at a rate of 400 000 tpa.

Jan 1, 1989

The gas drainage characteristics of two seams, the Bowen at Bowen No. 2 Colliery, Collinsville, and the Gemini at Leichhardt Colliery, Blackwater, are assessed. Single borehole tests and drainage panels were studied by underground monitoring of pressures and gas flows. Permeability was found to be effected by cleat to an order of magnitude. Other structural features are shown to be important. In this context, the need for delineation of no-flow zone locations in boreholes is shown to be of great importance where in-seam pre-drainage is being used for outburst control. Water in the seams strongly influences permeability causing gas flows to fluctuate with time. Use is made of modified reservoir engineering techniques to analyse the drainage characteristics of seams.

Jan 1, 1982

With the progress of modern mining engineering, one of the features of which is the mining from greater depths and the hoisting of greatly increased loads, it becomes a matter of increasing importance that the engineer should be able to determinewith some degree of precision the character of the strains on the hauling rope. But a wire rope is a complex structure; it is made up of spirally-twisted strands, which in turn are composed of spirally-twisted wires, and it is not particularly easy to say exactly what happens when this "doubly-twisted structure is wound round a drum or over a pulley.. The difficulty has been generally evaded in ordinary practice by the simple device of adopting a large factor of safety for the rope-usually from 8 to 10-a factor which experience has shown is sufficiently large to cover the bending strains set "up when the rope is passed over pulleys of the sizes commonly considered appropriate.When, however, we add the stress due to the bending of the rope to the stress produced by" the direct pull, we find that the actual factor of safety is usually more nearly 4 than 10, and frequently the bending stresses in the rope are so large compared with the simple tensile stresses that their neglect may easily lead to disastrous results when dealing with problems a little out of the common run. Common Empirical Rules.-It is always "recognized that the bending of a wire rope round too small a pulley is likely to do the rope serious injury, but as it is desirable in ordinary winding operations to reduce the inertia of the moving parts to a minimum...

Jan 1, 1907

By Cox LT

A short term tyre study of trucks operating in a multiple pit surface coal mine showed significant potential for cost savings. The tyre study, conducted on-site over a three months period covered a mixed fleet of 18 trucks ranging from 27 tonne to 77 tonne capacity operating on overburden removal, coal haulage and watering duties. Some existing plant history records and a variety of tyre related measurements during the course of the study allowed the current state of tyre operations to be quantified. Specific attention was given to determining ger>ral trends from historical records and conducting detailed studies of individual lug damage, pressure monitoring and rectification, as well as tyre maintenance procedures. Important haul road parameters including camber, gradient, curve radii and superelevation, constructional materials and surface clean-up were appraised for their influence on tyre wear. Recommendations for achieving long term cost effective tyre utilisation included increased tyre maintenance, personnel development, compliance with haul road design parameters and more stringent clean-up Procedures.

Jan 1, 1982

Investigation of standard tests used to establish the decrepitation rating of Western Australian iron ore showed scatter in results which could be reduced by textural type sampling. Testing of individual textural types resulted in separation.of a range of decrepitation behaviour patterns. No unique correlation was established between water content in goethite, or between any single mechanism and breakage in shock heating. The latter depends rather on several mechan- isms whose operation is controlled by the texture of the ore. Texture studies were used successfully to predict decrepitation behaviour which could be related to orebody structure for mine planning, and blending for sales or processing requirements.

Jan 1, 1973

Tectonic subsidence plots have been calculated for well, extrapolated-well and significant off-well (seismically-based) locations in the Vulcan Sub-basin and adjacent highs (western Timor Sea). The subsidence curves have been normalized to a common datum, the distinctive "near top Permian" marker, and corrected for sediment compaction, palaeobathymetry, eustatic sea-level change and loading effects.Four principal phases of post-Permian basin development are recognised and quantitatively described by integrating the results of the sub-sidence analysis into the regional (e.g. recent Ocean Drilling Program-derived) framework of the tectonic evolution of the North West Shelf. They are1. the Triassic-mid Jurassic Westralian Superbasin intracratonic phase,2. the late Jurassic-early Cretaceous North West Shelf rift phase,3. the mid Cretaceous-Palaeogene North West Shelf subsidence phase, and4. the Neogene-present Timor collision phase. Rapid Triassic tectonic subsidence occurred in an intracratonic setting, possibly subsequent to aborted late Palaeozoic rifting. Intracratonic sub-sidence mechanisms such as deep crustal metamorphism and/or intrustion and regional tectonic compression are invoked in addition to any post-rift thermal subsidence which may have occurred.

Jan 1, 1990

By Akerkar D. D, Dey M. L, Mathur S. B, Chowdhury S. K R

The extraction of gold and silver from chalcopyrite concentrates has been investigated. In view of the recent interest in non-cyanide leachants for gold and silver, one such alternative reagent, namely thiourea, has been employed in the present work. Precious metal leaching was attempted from received copper concentrates as well as pre-oxidised concentrates. Pre-oxidation of the concentrates was carried out by three different methods, namely roasting, pressure oxidation and biological oxidation. After pre-oxidation and leaching of the base metals, the leach residues were subjected to further leaching for precious metal extraction. The results obtained on the extraction of gold and silver from received concentrates as well as pre-oxidised concentrates are presented and the effectiveness of the three pre-oxidation routes employed is compared.

Jan 1, 1992

By Walton M. C

A combination of flotation and smelting technologies is proposed as a cost-effective means to maximise the revenue of base metal operations. The proposed treatment route breaks the grade - recovery nexus associated with the treatment of ores exhibiting difficult mineralogy in conventional plants. Aspects of the two technologies are reviewed and typical capital and operating costs presented. A significant improvement in revenue is demonstrated in a worked example, where a copper-lead-zinc operation is examined in terms of the conventional and proposed treatment options. For the selected ore, the net smelter return per tonne of mill feed improved 57 per cent, from US$89.70 to US$141.10 with the proposed treatment option. This represents an additional US$51.4 million in annual revenue. Metallurgical operating costs increased by US$20.12 per tonne of mill feed for an incremental capital requirement of US$30.3 million for an existing operation.

Jan 1, 1992

The Iron Prince orebody occurs within the Lower Middleback Jaspilite Horizon of the Middleback Group and consists of hematite within host rocks of jaspilites and schists. The ore was probably the product of leaching of silica from jaspilites and replacement by iron, concentrations occurring in suitable structural traps. The narrowness and the presence of extensive dolerite amphibolite dykes within the orebody make it essential to operate a grade control programme in advance of the faces. Information from drilling is drawn up on bench plans, step plans and impurity overlays, and these serve both in day to day production planning and in long term planning. Mining is done selectively by open-pit methods and blending conducted by keeping at least three faces of different grades of ore open at any one time. No stock piles of ore are kept for blending, but contact ore, contaminated ore and enriched material are dumped for later beneficiation.

Jan 1, 1971

A conventional Bucket Wheel Excavator (BWE) system with conveyor transport, mobile tripper and spreader was commissioned at the Goonyella Mine in 1982. The system was introduced to prestrip ahead of dragline excavations and was specified to remove 7.5 million cubic metres per annum in ground somewhat harder than that inwhich bucket wheel excavators are normally operated.This machine has, since 1982, moved more than 77 millionbank cubic metres of material and has been relocated twice. Extensive trials have been undertaken including digging blasted rock.

Jan 1, 1992

By B Hou

The Eucla Basin in southern Australia is emerging as an important global source of zircon from heavy mineral sands. Understanding the geological evolution of the basin and movement of heavy minerals down peripheral paleovalleys and along paleocoastlines is essential to effectively refine exploration strategies for heavy minerals in the basin. Integration of geoscientific datasets in a Geographic Information System (GIS) environment has proved to be effective in reconstructing depositional environments along the Cenozoic basin margin and in tracing the buried paleorivers that once drained broad areas of the Archean-Paleoproterozoic Yilgarn and Gawler cratons, the dominantly Mesoproterozoic Musgrave and Albany-Fraser Provinces, and the Neoproterozoic-Early Paleozoic Officer Basin. Sea level highstands during the late Middle Eocene (39 - 36 Ma) are associated with formation of the Ooldea coastal barrier complex and the zircon-rich heavy mineral deposits at Jacinth, Ambrosia and Tripitaka. More extensive transgression during the Late Eocene (36 - 34 Ma) built the complex Barton shorelines that host the Cyclone deposit and the extensive ilmenite-dominated occurrences of the Barton West prospect. Multi-generation reworking of the source sands is indicated by the high proportion of deposits that are zircon-rich relative to titanium minerals. The age distribution of zircon grains in heavy mineral concentrates from the Ooldea and Barton barrier systems points to the Musgrave Province as the predominant ultimate zircon source. Paleorivers discharging along the northern basin margin presumably carried a sediment load that was then redistributed by easterly longshore drift to build the extensive coastal sand deposits along the northern and eastern basin margin. The south-eastern extension of these deposits was reworked during Miocene-Pliocene (15 - 2 Ma) times into a series of regressive strandlines that show angular discordance with the Eocene coastlines. This discordance is consistent with evidence for long-wavelength tilting of the Australian continent from Middle Miocene times, as the continent drifted toward a dynamic topographic low induced by convective mantle processes associated with the South East Asia subduction systems. The Dromedary and Gulliver’s deposits probably formed at this time. Ongoing research is focused on the geological features of the basin that influence heavy mineral transport, concentration and preservation, and the processes leading to deposits with high zircon content.

Oct 5, 2011