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Krupp Polysius AG, FRG, in close cooperation with Prof. Dr. K. Schoenert, FRG have developed the principle of the high pressure grind- ing roll POLYCOM. The POLYCOM mill basically consists of two counter-rotating rolls of large diameter and relatively small width, one of which is fixed and the other moving in slide blocks. The pressure required for comminu- tion is applied via the sliding roll by a powerful hydraulic system. The comminution takes place between the rolls under high pressure in the bed of material by nipping and compacting. The top feed size-depending on the rolls diameter -may be as coarse as conventional secondary crusher feed and the product is a compacted cake containing a high amount of fines created by micro-cracking. The amount of fines depends on the pres- sure (grinding force) applied. Operating results show that even in wet griding circuits capacity increases at downstream connected grinding mills of up to 100010 can be accomplished with an interconnected POLYCOM machine and energy savings of up to 25070 may be achieved depending on application. POLYCOM can be used in existing grinding plants for low-cost upgrad- ing of capacities but also as an advanced alternative to conventional crush- ing and grinding equipment in open or closed circuit configuration. A single industrial size 2.8m roll diameter POLYCOM machine may be fed with top feed size of up to 200mm and produce a finish product as fine- grained as known from rod and ball mills but with less energy consumption. Meanwhile, the POLYCOM high pressure grinding roll has established itself world-wide in the cement industry and is now entering the mining industry. POLYCOM machines are currently designed in industrial standard sizes of 1.0m to 2.0m rolls diameter and drive units of up to 2400 kW. This paper includes: principles of high pressure grinding, main fea tures of the POLYCOM machine, results of tests on various materials including Australian gold and copper ores carried out at the POLYSIUS research centre in Germany. Some examples of industrial applications of high pressure grinding will also be presented.

Jan 1, 1988

By Nguyen V. V

The development of structural defects in the overburden material immediately behind a production blast was studied using surface and subsurface techniques. A significant increase in vertical and horizontal fracture intensity was recorded. The extent of fracturing into the highwall appeared to be dependent on the structural and petrologic characteristics of the various lithological units and the relative position of the explosive charges. A shallow zone of disruption to a depth of 10 m and extending to around 30 m from the newly formed highwall crest was recorded. Horizontal fractures in lower units of the overburden sequence were recorded at distances up to 50 m from the new highwall Face.

Jan 1, 1981

By Buizen M

The results of calibration trials conducted on parachute stoppings under a recently completed NERD&DC grant are presented. Applications of parachute stoppings, for rapid regulation and control of ventilation networks are described including use in mine recoveries, sealing sections and rescue work. Parachute stoppings are one of a series of non-rigid ventilation control structures specifically designed for quick installation in emergency situations, for use in high production/rapid advance areas and areas suffering roof-floor convergence.

Jan 1, 1988

By Pala J

The Ellalong Colliery has been the first to mine the Greta Seam using the longwall method. Analysis of data from geotechnical monitoring has pointed to the role of the strong, massive sandstones of the Branxton formation in the development of loads on the powered supports and pillars. Failure of the sandstone intermediate-roof has been related to first-weight and periodic weighting, measured on the supports, using simple "voussior" analysis. Stress changes, including triaxial components measured in the barrier and chain pillars, have been compared with 2- and 3- dimensional numerical models. The applicable range of the models for the prediction of pillar loads under the strong roof is discussed.

Jan 1, 1986

By R Skirrow, E Bastrakov, A Mauger, P

A new rapid spectroscopic core and chip logging and imaging system developed by CSIRO was evaluated by PIRSA and GA on a wide variety of mineralised properties in South Australia, including the Emmie Bluff, iron oxide copper-gold-style prospect on the Stuart Shelf. During a three-month campaign in South Australia in 2003 the system logged over 50 000 metres of core from the State Core Library, company prospects and mines. The new system uses automated core tray handling, continuous visible and infrared spectroscopy, and digital imaging, to characterise and identify dominant mineral species on core, chips and pulps, at spatial resolutions of ~1 cm (spectral data) and ~0.1 mm (image data). The system can log up to 1000 m of core per day and several thousand metres of drill chips. Mineralogy is pre-interpreted using specialised identification software trained on a selected suite of minerals showing characteristic absorption features within the measured spectral range. On core from the Emmie Bluff iron oxide copper-gold prospect, 470 km NW of Adelaide and 80 km SSE of the Olympic Dam Cu-U-Au deposit, the spectral mapping system was able to characterise a number of alteration zones enveloping the sub-economic Cu-Au mineralisation. These consist of distal white mica phases showing decreasing Al content towards mineralisation, a zone of increased iron oxide content in the hangingwall to mineralisation, and a zone proximal and coincident to Cu-Au mineralisation that is enriched in chlorite with variable Mg/Fe chemistry. Additionally the results show background spectral characteristics that mimic the magnetite distribution.

Jan 1, 2004

Esso Australia Ltd. operates a large natural gas producing system in the Gippsland Basin, supplying gas to the Gas and Fuel Corporation of Victoria, the State Electricity Commission of Victoria and several industrial customers. Gas reaches the Longford processing plants from three offshore platforms via a network of large diameter pipelines, which must be protected against the formation of ice-like hydrates. When gas production commenced in 1969, methanol was used to inhibit hydrate formation in the offshore pipelines. However, later investigations showed that the methanol was causing excessive degradation of molecular sieve in the onshore gas-processing plants. (Molecular sieve is used to remove water and H2S from the gas prior to further processing to remove heavy hydrocarbons.)

Jan 1, 1982

By Komosa T, Muir D. M

Adequate levels of dissolved oxygen are essential for efficient gold dissolu- tion. The actual levels in plantpuips can be seriously reduced by the presence of oxygen consuming reactive minerals, and reduced oxygen solubility in saline water. The rate of gold dissolution is then limited by oxygen availability rather than cyanide. Ion selective electrode dissolved oxygen meters can give an effective indication of the relative oxygen saturation, but they are not able to give meaningful values of dissolved oxygen in saline water, without custom calibration curves. When the dissolved oxygen concentration is rate limiting, the addition of oxygen or peroxide can improve gold leaching kinetics as well as reduce cyanide consumption.

Jan 1, 1991

By Swift D. G

For some time the Electricity Trust of South Australia (ETSA) has been investigating the application of new mining methods and equipment to minimise the cost impact of the steadily increasing depth of mining brought about by the 20¦ dip of the coal seams at the Leigh Creek Coalfield. Exhaustive examination of all suitable mining systems showed that highly mechanised systems involving belt conveyors displayed no eco- nomic or operational advantages over shovel and truck methods. However, the configuration of the Leigh Creek coalfield allows for two quite different approaches to mining by shovel and truck. The current strip mining method involves removing overburden from the highwall in 60 m to 200 m wide strips to progressively expose the coal down dip, and requires all waste to be hauled to the surface. The alternative ter- race haulback method involves opening a boxcut to full depth at one end of the coalfield, then mining the full section along strike and placing the spoil in the mined out area. On a strictly economic basis, the latter is clearly advantageous, but the former has significant less tangible advantages. In deciding between the two methods ETSA is faced with the need to examine the applicability of each method under a wide range of possible future demands on the coalfield, and to assess the importance of many intangible factors.

Jan 1, 1989

By T Hayward, G Lane, M Phillips

In December 2004 Phu Bia Mining Ltd commissioned Ausenco International Limited to conduct a feasibility study for its Phu Kham copper-gold project located in Laos. The feasibility study for a mining and processing operation treating 12 Mtpa of ore averaging 0.56 per cent copper and 0.25 g/t gold to produce an anticipated annual average 200 000 t of concentrate containing 25 per cent copper was completed in early 2006. The plant design incorporates a single processing line and includes a gyratory crusher, overland conveyor, coarse ore stockpile, SAG and ball mill grinding circuit, flotation circuit including regrind and three stages of cleaning, concentrate dewatering and concentrate load-out facilities. The Phu Kham copper-gold mineralisation comprises two principal styles: stockwork-disseminated and banded-massive sulfide within skarn limits. Primary copper in both mineralisation styles occurs as chalcopyrite and secondary copper sulfide minerals. Skarn includes the copper and gold mineralisation contained in pyrite, silicate, magnetite and haematite skarns, and in quartz-pyrite altered sediments. Both the stockwork-disseminated and banded-massive sulfide ores contain relatively high proportions of pyrite relative to the copper and gold mineralisation. Thus, the flotation metallurgy of the Phu Kham orebody is characterised by the need to reject a high proportion of the pyrite during differential flotation to yield a concentrate grade of approximately 25 per cent copper. The rejection of pyrite is accompanied by the rejection of some copper and gold and can result in modest metallurgical recovery. Consequently, the greater the pyrite content, the lower the expected copper and gold recoveries. The relative pyrite content is expressed on the basis of sulfur:copper ratio. For Phu Kham ores, the sulfur:copper ratios are in the range eight to 14 on a blended annual basis, but can be greater than 20 in the skarn components. Higher grades of copper and gold are also present in the skarn mineralisation. The design concepts for the concentrator were influenced by the need to provide a low capital cost approach for the project due to the relatively low grade of the ore and the modest metallurgical recovery. The concepts used to minimise capital cost whilst retaining operating and maintenance flexibility are discussed, together with the metallurgical challenges imposed by the high pyrite mineralisation.

Jan 1, 2007

By Conochie DS

SIROSMELT is a successful new pyrometallurgi- cal furnace system using a top-entry lance which can be submerged in both slag and matte. The lance is of simple construction, and is cooled by process air. Pilot plant work commenced in the CSIRO Division of Chemical Engineering in 1972 using a 50 kg batch reactor. This paper traces the development of the technology through various slag cleaning and smelting processes up to a scale of 5 tonnes per hour continuous feed. Strong co- operation between CSIRO and the Australian smelting industry has contributed greatly to the success of SIROSMELT.

Jan 1, 1984

By Horowitz F. G, Lamb P

As mining operations become larger and more complex, larger volumes of geological, geophysical, and production data must be manipulated and interpreted on a day-to-day basis. Because of the large volume of data, more sophisticated data storage strategies, interpretation tools, and visualisation tools must be used by exploration and mining operations in order to remain competitive. Critical to better practice is an understanding of the basic syntax and character of geological and mining data, expressed in the form of a data model. In the short-term, a data model can be used to implement or evaluate schemes for data storage or exchange. It can be used to evaluate software. In the longer term, a data model is essential to the design of the next generation of software for 3D geological modelling. In this and the related paper (Lin et al, 1995) the data model in use by CSIRO is presented, together with: 1. examples of the use of data transfer in the linkage of existing mining software; and 2. examples of the use of the data model in software design.

Jan 1, 1995

By C A Heinrich, Morse M. P, Cruickshank B. I, Pyke J. G, Whitaker A

Very little public domain information is available on the exploration signature of the Coronation Hill Au+Pd+Pt deposit. From 1987 to 1990 the BMR (now AGSO) carried out geological, geophysical and geochemical (whole-rock, stream, soil and rock chip) surveys within the South Alligator and Kakadu Conservation Zones and defined several key parameters useful for exploration programs. The essential geological ingredients for the style of Coronation Hill Au+Pd+Pt¦U deposit are oxidised, low pH fluids, dilatant fault structures, a thick neutral to oxidised cover sequence and chemical traps in the basement. In geophysical data, the areas surrounding the mineralisation can be detected by airborne magnetics as major lows in magnetite-rich rocks, whereas in airborne gamma-ray spectrometry data, imaged spectrometric channel ratios such as U2/I'h and U2/K highlighted alteration surrounding the deposits. Three types of stream-sediment and soil samples were taken from each site: (1) -1 mm mesh, 5 kg sample for bulk cyanide leach (BCL) analysis for Au, Pd, and Pt; (2) 1 kg sample of -1 mm mesh sediment for fire assay/ICPMS analysis for Au, Pt and Pd; and (3) 50 g - 180¦ mesh sample for a variety of trace element analyses, including Au, Pd and Pt. Techniques 2 and 3 gave similar results for Au, Pt and Pd, while the recovery rates for Pd and Pt from the BCL samples were considerably lower. Other trace elements did not define unique indicators for Pt or Pd mineralisation, as each sample reflected the dominant lithology in the drainage basin. Rock chip surveys were useful in determining which faults were associated with the ore fluid in regions of multiple fracturing. Results from these exploration-style surveys also confirmed that the Coronation Hill deposit is a variant of the unconformity-style of mineralisation, as all significant geochemical and/or geophysical results occur at or below the unconformity.

Jan 1, 1994

By Anderson RJ

Tower Mills are used at Aberfoyle's newly commissioned Hellyer base metal sulphide concentrator. Hellyer ore is particularly fine grained. To achieve adequate liberation fine grinding is necessary. Three Tower Mills are used on regrind duties, grinding to less than 20 microns. The physical arrangement, material flows and grinding characteristics for the Hellyer Tower Mills are described. The mills have performed satisfactorily, both in size reduction and power efficiency. Wear parts must be inspected and changed more often than with ball Mills. To date, 92 per cent availability has been achieved. As parts and maintenance routines are rationalised, this is expected to improve to 96 per cent. Modifications to wear parts for the Hellyer Tower Mills are discussed.lhc Tower Mill grinding environment is highly reducing. The impact of Tower Mill regrind on downstream flotation is discussed.

Jan 1, 1991

Broken Hill is situated at an elevation of approximately 1000 ft. above sea-level, on the Barrier Ranges, in the State of New South Wales, Australia. It is approximately 700, 280 and 330 miles from the ports of Sydney, Pirie, and Adelaide, respectively.The summers are usually hot and dusty, with a recorded maximum shade temperature of 114° F. The rainfall averages approximately 9 in. per annum.

Jan 1, 1932

The mineralogy, maero- and micro-textures of Thackaringa ore are simple and have many counterparts among base metal-quartz-siderite vein type deposits elsewhere.The ore consists predominantly of galena, sphalerlte, chalcopyrite, tetrahedrite, and arsenopyrite in a quartz and siderite gangue. Silver minerals, as such, appear to be lacking and silver values are no higher than in other sulphide ores of this type. These features contrast very markedly with those of the A.B.H. Consols Lode which appears to have emanated from the north end of the Broken Hill Main Lode Horizon during high grade regional metamorphism. The Consols Lode has been regarded as of Thackaringa type, and both are regarded as possibly arising from the remobilization of Main Lode Horizon ore. Whilst this may yet prove to be so it appears that the marked differences in mineral composition between the Consols and the Thackaringa types, would require somewhat different modes of regeneration.Thackaringa ore, as well as A.B.H. Consols ore, on this basis, would necessitate the development of a metahydrothermal ore fluid to account for their present apparently hydrothermal (or pseudo-hydrothermal) constitution...

Jan 1, 1967

The products from beneficiation present themselves at opposite ends of the spectrum, and yet numerous synergies exist in the preparation of coking coal and hematite iron ore products for their common export markets. Returning to the coal side of the business with Anglo Coal following a five-year sojourn in WA with Hamersley Iron, has provided the opportunity for comparing and contrasting some of the key synergies of the supply chains of both bulk commodities.Comparisons include consideration of things like: resource evaluation (especially quality aspects), run-of-mine handling and preparation, beneficiation, product handling and transportation, quality assurance and customer awareness, value-in-use and impacts on iron and steelmaking, and supply chain environmental aspects.Inherent within these are several other notable contrasts including: æseamsÆ and æorebodiesÆ, rocks and minerals, rejects and tailings, oxidation and weathering, suppliers and users, and marketing and purchasing, to name but a few.This paper covers some of the more interesting of these synergies and raises some potential opportunities for sharing knowledge and innovation between the two areas of activity in the future.

Jan 1, 2005

The Shamrock Gold Mine has been brought from exploration to production within three years. Mining of the openpit is scheduled for June 1990 with commissioning in April of the 180 000 TPA carbon-in-pulp mill on old tailings and rock dumps. The development of a small openpit containing 344 000 tonnes at 3.6 g/t Au in a complex sulphide ore has required extensive metallurgical testwork to optimise recovery, and ensure profitability. The project has been undertaken in a changing economic climate, with increasing restrictive legislation. The decision to mine was further complicated by the escalating cost of installing a heap leach operation in South East Queensland. Decreasing costs of consumables, in particular sodium cyanide, and the opportunity to purchase a suitable transportable mill at a reasonable price made the project robustly viable as a CIP operation.

Jan 1, 1990

By Ross R

Although mining is an old industry its management is quite a new science, and its complications are now being recognised as demanding expert knowledge in many branches of technical and professional education. Not the least amongst these isaccountancy, for probably its most important problem is "How to control the expenditure." Unlike most businesses a mining company stands almost entirely in the light of a purchaser in the world's markets, and not as a seller, except say for product so the established and perfected systems of modern industries cannot be adopted for mining purposes. For this reason it has been left for late years to consider the matter seriously, and now a number of well-managed concerns have devised costs systems to suit their own requirements.Very little, however, has been published and even that is disjoined and difficult to make use of. Some of the costs systems in vogue, although elaborate and imposing, are not of very great value for keeping check on wasteful expenditure, or for displaying the commercial effect brought about 'by any particular change in practice, or by an addition or alteration to a portion of existing plant.

Jan 1, 1911

By Bhaskara Sarma P V R

Solvent extraction of cobalt from an ammoniacal ammonium sulphate medium was carried out using Di(2-Ethyl Hexyl) phosphoric acid in kerosene as diluent. The effect of ammonium chloride and ammonium sulphate on the extraction efficiency was studied. The extracted species in the ammonium chloride and sulphate systems were CoAz2HA.NH4CI and CoA3.HA.2(NH4)2SO4, respectively. Ammonia scrubbing and cobalt stripping studies were carried out from loaded and ammonia free organic Respectively.

Jan 1, 1992

The Central West of New South Wales is emerging as a significant metallogenic province. The development of Northparkes Mines (North Limited) and the Cadia Hill deposit (Newcrest) are establishing NSW as a highly prospective porphyry copper-gold province. Exploration in the area has been further buoyed by the Ridgeway discovery by Newcrest near Cadia. The fact that the Ridgeway prospect was discovered 300 m below surface under Tertiary basalt cover indicates that surface prospecting can no longer be considered alone as an adequate method to find significant new deposits.

Jan 1, 1997