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Dartbrook (Hunter Valley and South Bulli (Southern Coalfield) Collieries provide contrasting settings for gas sorption studies. Gas compositions at Dartbrook are dominated by carbon dioxide, with minor methane, while those at South Bulli are dominated by methane with minor carbon dioxide. Total gas contents at Dartbrook are also significantly greater than those at South Bulli. The two collieries are also contrasted in terms of coal composition and mining environment. Dartbrook Colliery mines a relatively small sectionb(4m) of very thick seam (up to mapproximately25m); the coal is vitrinite-rich, high volatile bituminous. South Bulli mines most of the seam thickness, with coal being an intertinite-rich, medium volatile bituminous coal.Coal samples have been collected from in-seam gas drainage holes for evaluation of relative gas desorption rate (methane versus carbon dioxide). Following adsorption isotherms, petrography, chemistry (proximate and ultimate analysis) and pore structure analysis (carbon dioxide surface area, mercury porosimetry). Bomb desorption studies indicate different behaviours for methane desorption at these two collieries desorbed gas compositions at South Bulli show a small enrichment in methane content. The opposite is observed at Dartbrook. Both collieries show enrichment in CO2 in the residual content. Adsorption studies show marked variation in adsorbed gas contents for methane and carbon dioxide at each colliery and between collieries. These variations are related to differences in coal pore structure, chemistry and Petrology.

Jan 1, 1998

By Russell J

A sustained drop in the grade of Mount Isa lead-zinc-silver ore occurred in mid 1980. It was decided to increase concentrator throughput from 200 000 to 240 000 tonnes/four week period to maintain budget metal production. To achieve this increase whilst maintaining acceptable grinding and flotation performance, crushing plant final product size had to be reduced from 100%-13mm to 1000-11.2mm. The goal in the crushing plant was to achieve a 20% increase in throughput with a 20% decrease in the top size of the product. This was achieved by operational changes to improve plant availability and optimisation of the existing crushing and screening equipment Performance.

Jan 1, 1978

By Kelly E. G

New Zealand suffers the disadvantage of widely scattered ore bodies, none of which is large enough to economically support its own smelter. This leads to the concept of a centrally located smelter which must be flexible enough to cope with var

Jan 1, 1980

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

By A G. Pavlides, B L. Weekes

The Sepon Copper Project is located in the Savannakhet Province of Laos PDR and is operated by Lane Xang Minerals Ltd (LXML). An Ausenco - Bateman Engineering joint venture, the Khanong Development Group (KDG) managed engineering, procurement and construction of the project. The plant was fully commissioned in March 2005, two weeks ahead of schedule. The plant is designed to produce 60 000 tpa of cathode copper. The process flow sheet includes a pressure oxidation (POX) circuit that leaches pyrite flotation concentrate to generate ferric ions and sulfuric acid for use in atmospheric leaching of a predominantly chalcocite ore. The process is unique in that the chemistry in the autoclave is forced to produce a basic ferric sulfate precipitate for downstream recovery of ferric iron. This paper describes the design, construction and commissioning of the pressure oxidation circuit. The challenges imposed on construction and commissioning due to the remote location of the site, landlocked status and underdeveloped infrastructure in Laos are highlighted.

Jan 1, 2005

By S Miller, R Smart, J Thomas

Single-addition and sequential net acid generation (NAG) experiments were carried out on natural and prepared samples with varying contents of organic matter and pyritic S. Results show that carbonaceous matter can produce significant quantities of organic acids during peroxide oxidation in the NAG test, which leads to overestimation of acid-forming capacity and misclassification of benign samples as potentially acid forming (PAF). Organic matter effects were most pronounced in samples with low S (less than 0.5 per cent) and total organic carbon (TOC) contents of greater than seven per cent. The single-addition NAG test will tend to overestimate acid potential in samples with little or no pyrite and high organic matter content, potentially leading to sample misclassification. High pyritic sulfur samples tend to show little difference in single-addition NAG acidities with increasing organic matter, and it appears that pyrite is preferentially oxidised by peroxide when present in significant concentrations (greater than one per cent pyritic S). In sequential NAG tests overestimation was greatest in samples with little or no pyrite, but highly carbonaceous (>20 per cent TOC) pyritic samples were affected in later stages as the pyrite was depleted. A modified NAG method is proposed to account for the relative proportions of pyrite derived acidity and organic acidity in a given NAG solution.

Jan 1, 2003

E Deposit is located at BHP BillitonÆs Area C iron ore operations in the central region of the Hamersley Province, Western Australia. It is hosted by the Marra Mamba Iron Formation, the lowermost unit of the Archaean to Lower Proterozoic Hamersley Group. Mineralisation at E Deposit East is contained within the Mount Newman Member of the Marra Mamba Iron Formation and extends into the lower West Angela Member of the overlying Wittenoom Formation. Use of a combination of geological and geophysical techniques has enabled the geological setting of the deposit to be qualified. Interpretation of detailed mine face mapping, downhole geophysics, geochemistry, geological logging and photography has identified D2- related thrust faulting, with substantial south-over-north displacement. Similarly, in-pit mapping at the nearby C Deposit has revealed intense localised D2 deformation, including overturning and thrust faulting. The interpreted structure illustrates that iron ore deposits in the central Hamersley Province can be intensely deformed and require detailed geological investigation utilising technical data from mapping and drilling to enable the creation of robust grade-models for the mining operation.

Jan 1, 2007

Controlled recirculation of nine ventila- tion air is becoming an acceptable practice world-wide. A brief review of operating and planned schemes is given which illustrates the various purposes for using controlled recircu- lation in different types of mines. A de- tailed description is given of the operating and proposed schemes on South African gold mines. This is followed by a description of some theoretical and experimental work which has recently been carried out into certain important aspects of controlled recircula- tion. This includes: safety systems, dust filtration, blast contaminant removal, radia- tion hazards and the development of an expert computer program for the design of controlled recirculation systems.

Jan 1, 1988

By M Hino, D R. Swinbourne

The thermodynamic properties of arsenic in metal, speiss, matte, slag and gas phases are first summarised in this paper. Arsenic associates with sulphide minerals and generally has compounds of high volatility, but it has a weak affinity for sulphur and a strong affinity for metals, especially copper and iron. In the initial stage of the oxidation of sulphide concentrates arsenic is volatilised easily prior to the oxidation of FeS, although it tends to be fixed in the condensed phase as FeAsO4 if the concentrate is over-oxidised. Thermodynamic simulation of oxidative copper smelting reveals the distribution of arsenic between matte, slag and gas, and the possibility of condensation of arsenic from the resulting waste gas is discussed. In reductive smelting more arsenic remains in the metal or matte, and is sometimes concentrated as a separate speiss phase. The phase relations and thermodynamic properties of speiss are also summarised briefly. Arsenic refining from smelted copper metal is shown, from an examination of the basic principles of arsenic removal into slags, to be difficult. Owing to its weak affinity for lead however, arsenic refining from lead bullion is seen to be much easier.

Jan 1, 2000

By Sneyd R. J, Walton M. C

In early 1987 Minproc acquired a license from the inventor to engineer and construct acid plants incorporating the Fattinger technology. The process offers a simple and reliable method of producing sulphuric acid from metallurgical off gases at significantly lower capital and operating costs than the more familiar contact process. The process also offers the simultaneous production of nitric acid, if the NOx content of the off gases is high enough. A development of this latter process has other applications within the minerals industry, particularly in conjunction with refractory gold ore preoxidation.

Jan 1, 1989

By Hutchinson IN

In order for the Australian underground coal mining industry to achieve the high productivity rates demanded of it without compromising its good safety record, improved geotechnical monitoring systems are required. One of the main problem areas affecting underground coal mining is the deterioration of previously stable roadways.CSIRO Division of Geomechanics has been working on a NERDDC funded project to develop an instrument to monitor coal mine roof deformation. The instrument which has been developed, Roof Alert, is a self contained, battery powered, intrinsically safe device. It can monitor the magnitude and rate of deformation and give multiple, variable visual alarm signals where preset levels ate exceeded.

Jan 1, 1991

The task of designing stable high walls and spoil piles in strip coal mines, and stable openings with controlled roofs and floors in underground collieries - within the constraints normally imposed by economics - depends upon a reliable assessment of rock mass strengths and rock mass reactions under a variety of stress conditions. Of the geological factors influencing internal friction and cohesion within rock masses, many may be determined qualitatively or empirically from bore-hole evidence. Rock types, descriptions and properties of intact rocks, location of boundaries, limits and degrees of weathering, potential for slaking or decomposition of rocks when exposed, bedding characteristics, the nature of rock anisotropy and the likely effects of water on rock mass properties can be assessed from bore- hole data. Discontinuities, whether they be major such as faults and dykes, or minor such as joints and fractures, present a greater problem, and in most instances the mine geologist must resort to additional techniques to describe or predict their occurrence, nature, frequency, intensity or physical properties. Information on ground water and seam gas is available from bore-holes within certain levels of reliability.

Jan 1, 1977

By A V. Nguyen

Spherical calcium dioleate particles (~10 ¦m in diameter) were used as AFM (atomic force microscope) probes to measure interaction forces of the collector colloid with calcite and fluorite surfaces. The attractive AFM force between the calcium dioleate sphere and the fluorite surface is strong and has longer range than DLVO (Derjaguin-Landau-Verwey-Overbeek) prediction. The repulsive AFM force between the calcium dioleate sphere and the fluorite surface does not agree with the DLVO prediction. Consideration of non-DLVO forces, including the attractive hydrophobic force and the repulsive hydration force, was necessary to explain the experimental results. The non-DLVO interactions considered were justified by the different interfacial water structures at fluorite- and calcite-water interfaces as revealed by the numerical computation experiments using molecular dynamics simulation.

Jan 1, 2005

By M Maulen, K van Olden, T Elkington

A large open pit is planned at the site of an existing underground mine. Strategic planning work has been undertaken to investigate the project value associated with an expansion of underground operations in conjunction with the proposed pit. Previous analysis determined that any depletion of the available pit resource that changes the optimum pushback sequence has a significant negative impact on overall project value. Therefore, to investigate the viability of an underground expansion requires a system to identify the stope resource that would add value to a combined operation if mined ahead of the pit. The key solution to this problem was to generate a resource model variable that defines the blocks, which have greater discounted value if mined by stoping rather than by the open pit. A key assumption was that the open pit is the main driver of overall project value. From the identified potential underground resource, series of mineable stope shells were generated at a range of cut-offs. This stope reserve data formed the input to a mixed integer program based software tool that was developed and used to optimise the underground mining plan, at conceptual level, for various project configurations. A dynamic programming tool was then applied to evaluate the optimum value of a combined open pit and underground operation. The overall objective of this project was to determine the strategic plan that yields the optimum value for a combined undergroundûopen pit operation. The results provided a clear focus and direction for more detailed design and planning.

Jan 1, 2009

By N J. Beukes, J Gutzmer, C Reinke, M Bau

In this study the light sparse phase search (SPL_Lt) mode on the Mineral Liberation Analyser (MLA) was successfully used to identify and quantify the abundance of rare earth element (REE) phosphates in Precambrian iron formations. Monazite (light REE phosphate) and xenotime (Y and heavy REE phosphate) are identified and data from the MLA combined with the mineral chemistry of the two minerals are used to calculate and model the expected REE concentration and distribution in these two REE phosphates. The REE phosphates account for up to 31 per cent of the REEs in the banded iron formations (BIFs) and excellent correspondence is observed between the modelled REE patterns and the whole rock geochemical data available for the same samples. Except for quantifying the mineral weights, the sparse phase search also allows for the localisation of REE phosphate grains and the observation of their association with other minerals using backscatter electron (BSE) imaging. These observations are used to conclude that the REE phosphates were most likely of diagenetic origin, with REEs and phosphate remobilised from primary chemical precipitates. It is demonstrated that automated mineralogical techniques can be used to qualitatively and quantitatively describe the influence of a rockÆs trace mineralogy on its geochemistry.

Jan 1, 2008

The resource sector is conservative industry and people are resistant to change. The methods and procedures used to implement changes in process plants ultimately determine the success of such changes. The financial managers have a large say in where money is spent and the technical personnel must justify the cost and benefits for any expenditure. There are also others who believe it canÆt be done û æwe tried thatÆ. Implementing change needs a æChampionÆ who can assess the risks, plan, define the objectives and scope, set the goals, determine the key performance indicators (KPIs) and stay focused. This also requires preparing a budget and schedule and measuring against this. Contract management, reports and reviews are part of the implementation. Several case studies are given as examples of the implementation of process design changes to highlight the critical aspects involved.

Jan 1, 2009

To counter depressed world nickel prices, a continuing effort is being made at Kalgoorlie Nickel Smelter to reduce unit production costs. One major area in which production costs can be reduced is the substitution of coal for fuel oil. Two areas where this has been achieved to bring about a saving are, the addition of coal to flash furnace flux to reduce supplementary fuel oil requirements in flash smelting and the replacement of two oil-fired air preheaters with a coal-fired unit. These actions have resulted in coal replacing 67% of the current fuel oil requirement in flash smelting at the Kalgoorlie .Lckel Smelter.

Jan 1, 1987

The, Ore-bodies.-The ore-bodies of the North mine, North Broken Hill Ltd.; consist of two lenses, connected by a narrow neck of mineralized country. They pitch at an angle of 40° in an easterly direction and dip north at 60° to the horizontal. The southern ore-body, on a horizontal plane, has a total maximum length of 800 feet and in one place attains a width of 230 feet, whilst the northern orebody has a maximum'length of 600 feet and a maximum width of 80 feet.

Jan 1, 1940

By Sweet I. P

Stratigraphic correlations across the Mur- phy Tectonic Ridge are crucial to regional corr. elations between the Mount Isa and McArthur River areas. Recent work in the Westmoreland and surrounding areas has substantiated the earlier general correlations between the Mount Isa and McArthur River sequences. The Mount Isa and McArthur Groups, and their equivalents, remain prime prospecting targets for major lead-zinc deposits of the Mount Isa and R.Y.C. type. A prospective area for Redbank-type copper mineralization is suggested.

Jan 1, 1974

Heavy media separation serves to upgrade mill feed and reduce unit operating costs, allowing ores to be mined which could other wise be uneconomic. At the Aberfoyle mine at Rossarden in north-east Tasmania, a simple heavy media operation using a converted Akins screw classifier as a separating vessel, removes barren quartz from mineralised material. At the Cleveland mine at Luina on the west coast of Tasmania a more complex ore mix requires a versatile operation combining hydro-dynamic and static separation equipment to provide an efficient beneficiation circuit. The two operations are briefly described with a background of basic heavy media separ- ation practice.

Jan 1, 1978