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By C Morley, B Costello

In 2002 the Argyle Diamond Mine upgraded the process plantÆs recrush circuit to include a High Pressure Grinding Roll (HPGR), or High Pressure Rolls Crushers (HPRC) as they are termed in the diamond industry. HPGR have generated considerable interest over the last decade, though there are still technical/processing unknowns to its effectiveness as a primary diamond ore crusher.The upgrade of the Recrush circuit at Argyle Diamonds has gone a long way to answering some of the key questions, and thus it has reduced the unknowns to a level more acceptable to the industry.This paper focuses on the results from the HPRC at Argyle, in particular the performance of the studded wear surfaces, comparison of energy efficiency against traditional quaternary cone crushers and the resultant increased liberation. Issues that have arisen, including edge wear of the studded surfaces, will be discussed and the steps taken to reduce this issue are presented.

Jan 1, 2004

Geological information plays a significant, cost effective role, in the Mt Whaleback iron ore mining operations. The geology and structure are complex. Good communication between the Mine Planning Production Scheduling and Quality Control Sections is the key to utilisation of geological information to its full potential.Drilling and pit face mapping are the two basic sources of detailed data sets which are processed to prepare up to date geological cross sections and benchwise geological plans. This information is used directly for the blast pattern design and production scheduling. Physical ore type estimation is also undertaken. Orebody models are generated from the geological information.

Jan 1, 1990

By Griffith L, Lama RD

West Cliff Colliery mines Bulli Seam occurring at a depth of approximately 480 m. The Seam is intersected by a number of small shear zones and faults. While the faults have caused displacement of the seam, the shear zones are strike-slip structures with small apparent displacement of seam. Outbursts at West Cliff Colliery occur while driving through these shear zones. Few outburst wave occurred where faults have been intersected. In the last 3 years, over one hundred outbursts have occurred at West Cliff Colliery. The size of outbursts varies from a small bump to exceeding 140 tonnes of coal. A number of studies have been undertaken at West Cliff Colliery to control outbursts and predict Outbursts in advance of workings. These include: geological investigations, microseismic techniques, gas adsorption studies and gas drainage. The investigations to date suggest that outbursts of gas at West Cliff Colliery are more a gas phenomenon similar to what occurs in overseas mines. The results of various investigations are reported. West Cliff Colliery is located in the mid- west of the southern coal fields of N.S.W.

Jan 1, 1980

The Australian bulk explosives industry has matured significantly over the last five years and it would appear that the rest of the world is following suit. This maturity is characterised by the technical sophistication of modem bulk explosives, an increase in the technical competence of the explosives consumer and a greater openness in the debate on the quality and performance of explosives. The principal mechanism by which these advances have been made is undoubtedly commercial competition in the market place although a new element, technical competition between manufacturers and independent professionals, has and will continue to play an important role in the development of the industry. The relationship between the explosives manufacturer and consumer is necessarily both complementary and competitive. This paper identifies the need for the consumer to take a more prominent role in the critical analysis of the performance of explosives and to use his commercial influence to direct explosives manufacturers at least in the direction required for the future technical development of the industry.

Jan 1, 1990

The Electrolytic Refining and Smelting Company of Australia Limited (ER&S) operates a copper smelting and refining plant and is situated close to the heart of the highly industrialised area of Port Kembla. In March, 1982 the Company entered into an undertaking with the State Pollution Control Commission (SPCC) to monitor ambient levels of sulphur dioxide (S02) gases present in the atmosphere in the surrounding urban area. Despite the use of a 200 metre high stack for dispersal of the smelter waste gas stream at ER&S, two local suburbs, Warrawong and Primbee were experiencing on occasions high ambient concentrations of S02 resulting in discomfort to local residents. In late March 1982, ER&S installed a highly advanced S02 monitoring system to continuously monitor the levels at Warrawong. The system was extended to include S02 monitoring at Primbee in November 1982, and further extended in June 1983, to include an input of meteorological data. Initially the system was designed to monitor and react to high concentrations of S02 at either of the two monitoring stations. Currently however, refinement is taking place to allow a predictive nature to be built into the system such that it not only reacts to an adverse situation but can predict weather patterns likely to cause high concentrations and thus avoid these events. The entire system is still undergoing a growth and development period, however the results obtained to date are pleasing to both the Company and the SPCC.

Jan 1, 1984

By Paine GG

The in-situ retorting of shallow oil shale deposits is an attractive alternative to the material handling problems of conventional open pit mining techniques, which involve removing overburden, fragmenting and transporting the shale to a fixed retort, and finally disposing of the hot spent shale.For in-situ retorting to be successful, the oil shale has to be fractured and the fragmented rock expanded into a void, to allow controlled propagation of a flame front through the in-situ retort. The principles of cratering with explosives have been used to develop a process for the in-situ fracturing of a thin oil shale deposit overlain by a formation of porous rock. The overlying porous rock formation is first compressed by explosive charges to create voids in the porous rock. The oil shale is then fragmented and pushed in to the voids with separate explosive charges. This paper discusses methods of creating voids in porous rocks with minimal surface disturbance, and then methods of obtaining the most uniform fragmentation of the shale. The whole process can be completed, in practice, in one blast. The results of an experimental blast are presented, and possible modifications are then discussed.

Jan 1, 1985

By M Fylak, R Wenda

Advanced preparation techniques open new ways for SEM and X-ray diffraction (XRD) investigations on hydrating cementitious systems. In this paper the early time hydration of Portland cement is studied with advanced cryo scanning electron microscopy techniques in combination with in situ X-ray diffraction and heat-flow calorimetry. The application of preparation techniques and analytical methods to Portland cement hydration are presented and discussed. Some aspects of hydration reactions are focused. The reaction products of the first minutes, changes in ettringite morphology, AFm formation during the deceleration period and the visualisation of C-S-H microstructures were special points of interest. X-ray diffraction analyses and Cryo-SEM images gave essential information about phase development, reaction kinetics, microstructure and morphology of hydration products. Portlandite, AFt and AFm phases were detected by in situ XRD. Cryo-SEM analyses enabled high resolution imaging and EDX-analyses of cement particles and reaction products. The results of the different analytical methods were compared to obtain detailed information about crystallisation processes and microstructural development during the first three days of Portland cement hydration.

Jan 1, 2008

Thirty six different commodities were recorded from 3708 mineral occurrences in the Atherton 1:250 000 Sheet area, mapped by personnel of the Queensland Department of Resource Industries. Tin, occurring in 56% of all mineral occurrences, is the most common, followed by copper, tungsten, silver, lead, gold, fluorite molybdenum, zinc and antimony. The densest area of mineral occurrences is the Herberton Mineral Field, one of the most intensively mined areas in the state.The majority of occurrences in the sheet area are fracture, fault or shear related vein or lenticular deposits, with subordinate types being pipe, skarn, endogreisen, disseminated and porphyry copper deposits. However the larger mines in the area are commonly of the subordinate types including the Red Dome gold-copper skarn, the Wolfram Camp and Bamford Hill tungsten- m olydbenum endogreisens, and the Vulcan pipe tin deposit. Significant gold prospects occur in quartz-antimony veins, breccia pipes and skarn deposits associated with rhyolitic porphyry dykes. A fluorite-gold association has been noted in several areas on the western side of the sheet.Mineralised fractures are predominantly oriented in a NNW direction which is the major trend in the Hodgkinson Province. Secondary N and NE directions are also present.

Jan 1, 1990

By Johnson N. W, Munro P. D, Pease J. D

The Lead/Zinc Concentrator of Mount Isa Mines Limited processes complex fine grained ore from the Isa and Hilton silver-lead-zinc orebodies, producing lead concentrate, zinc concentrate and (until 1996) a low-grade middlings (LGM or bulk) conc

Jan 1, 1997

By Gregory L. M, Phillips G. N

Although it has long been recognised that there is a diversity of minerals associated with Victorian gold deposits, the degree to which this mineralogy is systematic or haphazard has remained uncertain. Recent work by the authors and students under their supervision permits a sharp delineation of the boundaries between different mineralogical domains, and these are interpreted in terms of recent rapid advances in Victorian tectonics, and the regional framework of Victorian gold geology described in Phillips and Hughes (1996).

Jan 1, 1997

Longwall mining in Australia is approaching maturity. Longwall production from 'state of the art' Australian longwall mines now rivals similar US based longwall operations. Regrettably however, Australian gate road development rates in general fall short of the required development to longwall production ratios that are required to sustain annual longwall production capabilities. By contrast, most US based longwall mines achieve the required development to longwall production ratios to sustain their longwalls. This is despite many having to drive three heading longwall panel gate headings to meet regulatory requirements.

Jan 1, 1998

Mt. Whaleback is in the Pilbara region of Western Australia approximately 1200 kilometers north of Perth, the State capital. In this deposit the Mt. Newman Joint Venturers are mining ore reserves totalling 1500 million tonnes of high grade hematite averaging 64.0% Fe. In addition to Mt. Whaleback, 38 ore bodies have so far been identified outside Mt. Whaleback on the Company's remaining 75,000 hectares of lease area. These ore bodies contain major tonnages of iron ore. Extraction at present is planned at a rate of 37 million tonnes per annum at an ore-to-waste ratio of approximately 1 to 1.4. The ore is railed north to Port Hedland on the Indian Ocean where the different products are screened, crushed and blended prior to shipping. The purpose of this paper is to acquaint the reader with the facilities installed in the Mt. Newman operation to form a background to the sampling techniques employed, describe the precisions which were achieved in experiments conducted February through June, 1976 and also to assess the degree of blending which takes place during the various processes and to put a quantitative measure to the degree of blending. There have been many excellent papers written on the more theoretical aspects

Jan 1, 1976

By M McGeough

Following the success of calcrete sampling at Challenger, calcrete sampling has been widely adopted as the primary exploration technique for gold exploration, in the Gawler Craton. Calcrete is uniformly distributed over large areas and produces discrete gold anomalies. This allows drilling to focus on specific gold anomalous targets. However, despite widespread use of calcrete sampling, very little is known of the origin of calcrete in the Gawler Craton, and the link between calcrete gold anomalies and primary mineralisation. In an attempt to understand this association Lisa Gibbons recently completed an honours project at the Old Well Prospect approximately 45 km SSE of Tarcoola. Her work is part of a collaboration between CRCLEME, MESA and MIM Exploration. At Old Well, a calcrete anomaly (>10 ppb Au)covers an area approximately 7 km x 2 km with a peak value of 97 ppb Au. The study looked at the regolith as a whole, processes of its formation and nature of mineralisation within it. She was able to combine previous calcrete and drilling results with her own observations. The results from this study highlighted problems in relating surface calcrete anomalies to in situ gold mineralisation.

Jan 1, 1998

Although forty-seven years have passed since the by-product coke oven made its successful commercial appearance, it is only during the past fifteen or twenty years that this system of coal carbonisation has advanced rapidly to its present position ofabsolute supremacy.Early designs of by-product ovens proved more or less faulty, and the coke produced was so inferior to coke made in beehive ovens that there was a natural hesitancy on the part of coke producers to invest large sums of money in installations of by-productovens of doubtful utility-more especially in view of the fact that beehive ovens could be erected cheaply and operated by non technical labour for the production of high-grade coke under the most variable conditions of trade.Surely and steadily designers brought forward by-product ovens of improved type, coupled with more efficient apparatus for the recovery of by-products, but still the industry lagged, due almost entirely to the insistence on the part of coke users that the qualityof ordinary beehive coke was vastly superior for metallurgical operations to the best coke produced from by-product ovens. So deep rooted was this prejudice that only the passage of time could eradicate it. That it has successfully done so is strikingly illustratedin the following statistics:

Jan 1, 1928

The Cadjebut Mine is located 80 km southeast of Fitzroy Crossing. Cadjebut is owned 58 per cent by BHP Minerals and 42 per cent by Billiton Australia. Cadjebut is a 'Mississippi Valley Type' (MVT) deposit. Minerals present are sphalerite, galena and marcasite in a sedimentary host of dolomite and siltstone. The ore contains few deleterious impurities and no silver. The mill was commissioned in the first half of 1988 at a rate of 320 000 tonnes per annum. An expansion in the latter half of 1989 has since increased production to 550 000 tonnes per annum. The initial geological resource at the commencement of mining was 3.8 million tonnes at 13.5 per cent Zn and 4.4 per cent Pb. There is sufficient ore left to sustain operations to 1995 at a grade of 11.2 per cent Zn and 3.9 per cent Pb. The ore from underground is stockpiled on the surface via a drift conveyor and from the stockpile is fed into a grinding circuit consisting of a SAG and ball mill. Cyclone overflow at a Pgp of 90 pm gravitates to the flotation circuit. Lead and zinc are sequentially floated to produce an 80 per cent Pb grade at 90 per cent recovery and a 61 - 62 per cent Zn grade at 96 per cent recovery. The concentrates are thickened and filtered before being trucked to the port of Wyndham 600 km away. From Wyndham the concentrates are shipped to smelters in Asia, Europe and Australia.

Jan 1, 1992

By R Rodriguez, S Gumo

The Lihir Gold Mine, in Papua New Guinea, is a large open pit operation within an active geothermal system inside a collapsed volcanic crater. This unique setting has a big impact on the mine operation because of the occurrence of geothermal hazards. The system for managing geothermal hazards that has been developed by Lihir Gold Mine is a pioneering effort that can be applied to future mine discoveries in a similar environment. The controls are integral to the mining operations and allow mining to proceed whereas without them mining could not be considered. Truck and shovel productivities in conventional open pit operations are constrained by diggability, equipment availabilities and utilisation. At Lihir, additional constraints are in the form of 100 m exclusion zones around working shovels and 50 m exclusion zones around working drills. Given that the mine has seven large digging units and six drills, this amounts to a lot of area that excludes the presence of people on the ground. So how are the necessary work like grade control, survey, blasthole loading, and in-pit maintenance performed safely to achieve production targets? The answer is in the highly specialised procedures that have been developed that utilise geological, geothermal and geotechnical knowledge to predict problem areas and also deal with the organisation of movement in the pit for people and mining equipment. This paper will detail how scheduled material movement can be maintained despite the challenging conditions faced at Lihir Gold Mine.

Jan 1, 2007

By Baafi EY, Chatterjee PK

The quality of mine planning decisions ultimately depends on reliable estimates of the characteristics of the orebody. The quant- ifiable factors such as grades or thickness can be estimated from field data gathered from outcrops or exploratory drillholes. Since outcrop data is necessarily limited to the periphery of a deposit, extensive drilling generally is required. This paper outlines a method for selecting the number and location of additional exploratory boreholes using an iterative procedure based on a mathematical optimization concept called fixed point theory. The method is illustrated through its application to an exploratory drilling program for a coal mine where optimized locations gave a lower estimate of regional and block variances than a manual Choice.

Jan 1, 1986

By Smele J. S, Dawes W. D

In recent years there has been a trend among mining companies to diversify exploration and development away from the countries that have dominated mining activity for the latter half of this century. With some exceptions, this trend is accelerating and is a function of the recognition that many parts of the world, with no previous exposure to modern exploration, are endowed with considerable mineral potential. In addition coincident with changing political and economic circumstances, many countries have recognised the benefits of attracting international mining investment and have radically changed policies, fiscal and legal regimes so as to encourage exploration and mining. Some countries, however, have not readily accepted mining for cultural or social reasons and have yet to make effective changes to mining legislation. For historical reasons, other countries may have little or no direct experience of western economics, nor may they fully recognise the need for stability and competitive fiscal and legal systems to attract foreign investment. Not all ventures in new countries have been commercial successes and there have been some lamentable and recent lapses from grace. Company strategies, company standards and management objectives can also vary widely from company to company. What may be an acceptable risk or rate of return for one may be completely

Jan 1, 1997

By Lunt D

Arsenic is classified chemically as a metalloid. That is, it has properties intermediate between those of metals and non-metals. Like non-metals, it combines with many metals to form arsenides (eg arsenopyrite FeAsS, niccolite NiAs, sperrylite PtAs2), but like metals it forms sulphides and oxides (eg realgar AsS, arsenolite As203). Arsenic is distributed widely in the Earth's crust at an average concentration of 1.5 mg/kg and is present in more than 150 minerals.

Jan 1, 1991

By D Obeng, D Alexander

Over the past five years, commodity prices have been high and the focus of many plants has been æthe more metal the better, at whatever costÆ. In the recent economic crisis, the focus has shifted more to reducing the cost of production and operating at higher efficiency. Since 2002, JKTech has partnered with the Century mine in north-west Queensland to transfer technology and understanding through the good, bad and ugly economic environments, using methodology and techniques arising from research at the Julius Kruttschnitt Mineral Research Centre (JKMRC) and other research institutions around the world as part of the AMIRA International P9 Project. The JKTech studies were concentrated around the primary zinc circuit. During this period, Century expanded the primary zinc regrind capacity, installed additional scavenging capacity, installed and commissioned a Jameson cell for concentrate cleaning in the carbon preflotation circuit, and installed additional primary grinding capacity. Flotation circuit models were developed for each of the survey campaigns and enabled opportunities for further improvement to be identified, implemented and tested in the subsequent campaign.

Jan 1, 2009