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Over years of exploration the massive and tabular orebodies in the area to the South West of Western Areas Gold Mine had been assessed as containing about 50 million ounces of gold û a world class orebody. Planning initially was for a surface and subvertical shaft system to exploit this area but because of cost, a single lift shaft to an area which could be accessed ex Western Areas was planned to intersect the reef at 2760 metres. It was also planned to mine out the shaft pillar area long before the deep shafts would reach that position. This is not the normal practice in South African Gold Mines. The stoped out shaft pillar was backfilled to minimise movement in the shaft sites. The result of a competitive tender/adjudication process was that Cementation Mining û Skanska won and was awarded the R192 million contract to sink the Main and Ventilation Shafts on 15 June 1995. On 1 April 1999 Western Areas and Placer Dome SA formed a Joint Venture, which now owns and operates the mine on which the South Deep Shafts are situated. This situation prevails today.

Jan 1, 2002

By O Ostrovski

Direct iron smelting reduction has been examined using a modified 50 kg induction furnace. The furnace was equipped with continuous raw material feeding, a top oxygen lance, argon bottom bubbling, and sensors for measurement of gas and bath temperatures, gas composition and other parameters. In the base case, iron ore was charged at the rate of 1.5 kg/h, coke flowrate was adjusted to maintain a char fraction in the slag at 30 wt per cent, the oxygen flowrate was 100 Nl/min and the post-combustion ratio (PCR) was 60 per cent. The PCR was varied from 45 to 75 per cent by changing the lance height relative to the bath surface. Smelting reduction of Whaleback iron ore was investigated at different post-combustion ratios and iron ore feedrates using coke and coals with different volatile matter. The rate of iron oxide reduction increased with increasing iron oxide concentration in the slag, with a slight deviation from a linear function. The post-combustion ratio affected iron ore reduction and partitioning of elements between phases in the smelting reduction furnace. The high volatile coal investigated was found to be unsuitable for iron smelting reduction in the laboratory furnace.

Jan 1, 2000

Alliance Gold Mines was established in the early part of 1994 to acquire the assets of Diamin Resources NL at Maldon, Victoria. These comprised Exploration Licence 3422, some 20 sq km in area and enclosing the main part of the Goldfield, and a CIP plant - with a nominal capacity of 250 000 tpa - which was commissioned in 1988. Between 1988 and 1992 Diamin had mined - by open pit methods - and milled around one million tonnes of low grade gold ore, and recovered 55 000 ounces of gold. By 1992 the known shallow resources had been depleted. Historical gold production from the Maldon field is about 1.75 million ounces, at the surprising average recovered grade of 28 g/t. The last significant mine closed in 1926: since then there has been no comprehensive exploration program, though Lone Star Exploration NL tested part of the field for shallow open-pittable resources in the 1970s and Carpentaria Exploration Company Pty Ltd carried out widely-spaced drilling on the three main reefs from 1979 to 1982. Diamin (1983 - 1994) commenced a careful compilation of old mine records and newspaper clippings, and drilled several cored holes.

Jan 1, 1996

Stawell Gold Mines Pty Ltd operates two underground decline mines within the township of Stawell. An active exploration program and commitment by owners to improving the ore reserves has led to an improved mine life and reduced operating costs since the purchase of the operation by Mining Project Investors and Pittston Mineral Ventures in late-1992. Over the past six years of operation a cumulative 1 150 000 ounces of gold have been added to the mineral inventory. An improved geological understanding of the orebody has evolved over time increasing the ore reserves and allowing the development of long-term plans for the mines future. This has enabled important capital decisions to be made providing the impetus for improved productivity and thereby reduced operating costs. Co-operative mine planning and mine geology utilising best practice geological systems have enabled the effective extraction of a structurally complex and mineralogically varied deposit within a rural Victorian township. Detailed metallurgical research has improved the function of an aged and poorly designed circuit to boost the mill capacity whilst also improving the metallurgical recovery. The combination of metallurgical expertise and an understanding of the geological setting enable an effective control of metallurgical recovery.

Jan 1, 2000

Geologists employed by Metals Exploration Pty. Ltd. discovered nickel enrichment at Greenvale, 180 kilometres West of Townsville, in 1967. Subsequent drilling proved an ore body containing 45 million dry tonnes of ore containing an average of 1.5% nickel and 0.11% cobalt. The Freeport Minerals Company, who had experience in treating lateritic nickel ore, were invited to participate in development of the ore body. This resulted in the formation of the operating company Queensland Nickel Pty. Ltd., jointly owned by Freeport Queensland Nickel Inc. and Metals Exploration Queensland Pty. Ltd. With the completion of successful pilot plant testing of Greenvale ore at the Freeport research facilities at Belle Chasse, Louisiana, a treatment plant was constructed at Yabulu, 24 kilometres North West of Townsville. A 225 kilometre railway line was built connecting the Greenvale Mine and Yabulu Treatment Plant. The ore reduction and ammonia/ammonium carbonate leaching flowsheet is similar to that constructed and operated by the Freeport Minerals Company during World War II at Nicaro, Cuba. Modifications to the Nicaro flowsheet implemented at Yabulu include facilities to recover cobalt in a mixed nickel/cobalt sulphide product and the reduction of nickel

Jan 1, 1978

The T33-34 blast, the first major blast at Mount Isa Mines, broke 1,360,000 tonnes of copper ore using 349 tonnes of explosives. The original concept of firing T33, T34, T35 and U37 separately was changed during the life of the project due to adverse ground conditions. These conditions also caused the stoping method to be modified after the firing of the stopes had started. To stabilise the two stopes T33 and T34 where large fall off was occurring, rib pillars were left in the original slot. This caused the blast design to be more complex as these rib pillars had to "lead" the blast. The implication of such a large blast on the underground and surface environment was thoroughly investigated and precautions taken. The charging time of the blast was six weeks. Hook-up was started four days before the blast and continued until two hours prior to the blast. Detailed scheduling was carried out of other work that had to be done in the 24 hours before the blast to ensure that there were no delays in the firing.

Jan 1, 1977

In this paper is given a general description of the Black Star copper orebody, its relation to the lead orebodies and the controlling factors in the mineralisation.Copper ore, in the form of chalcopyrite, was first noted at Mount Isa in 1930 during the surface drilling campaign to prove the downward continuation of the silver-Iead-zinc orebodies.Details of the occurrence are set out in table 1.Other sub-commercial widths were also disclosed and examination of these occurrences showed that commercial mineralisation could not be expected within 800 ft. of the surface. It was therefore decided that further exploration was not warranted until underground workings had advanced to this horizon.Detailed surface mapping showed two small outcrops of the host rock of the copper orebody. One occurrence, 50 ft. x 75 ft., was of quartz, with leaching suggesting former dolomite. Another outcrop, further north and west of silicified shale, with low grade oxidised copper, has recently been found. Both occurrences were above the hangingwall of the main copper orebody.When the workings in the silver-Iead-zinc orebody reached No. 7 level (875 ft. below the surface) further...

Jan 1, 1953

By Q-c Li, G-l Gao

Cyanided tailings produced by gold processing operations may cause environmental problems, because they contain pollutants such as arsenic, sulfur and cyanide compounds. Moreover, tailings containing economic metals such as Au, Ag, Cu, Pb and Zn, are potentially valuable resources. In this article, cyanided tailings are catalytically oxidised by nitric acid in the presence of air or oxygen. The resulting solids may be leached to recover Au and Ag. The solution can be used to prepare ferric sulfate or iron pigment. Gases released in the reactions were recycled and reused by oxidation and absorption. All of these greatly improve metal recovery and the reuse prospects of cyanided tailings. Under the following conditions where the initial temperature of oxidation is 80¦C; initial concentration of nitric acid is 30 per cent (by weight); feed proportion (nitric acid to cyanide tailings mass ratio) is 3:1 and reaction time is two hours, the conversion ratio of cyanided tailings is 90.06 per cent. At the same time pyrite in the cyanided tailings is oxidised effectively, gold recovery is as high as 92.3 per cent and nitric acid loss per cycle is only five per cent because of NOx recovery.

Jan 1, 2007

By Borsaru M

The production of high-grade calcined bauxite is very dependent on the moisture content of the final product. Existing procedures rely on the ignition of small samples to monitor the effectiveness of the calcination process. The results obtained by this gravimetric technique are several hours behind production and do not permit regular adjustment of the furnace to optimize the control of the chemically bound water content (LOI).To provide rapid and hence more relevant results, a neutron moderation technique has been developed for measuring the LOI of bulk samples of calcined bauxite while they are still hot. The method uses fast neutrons from an 241 Am-Be neutron source to irradiate the samples, and the backscattered thermal neutrons detected are a measure of bound moisture content.The rms deviation between neutron and conventional determinations of LOI, in 15 calcined bauxite samples, was 0.08 per cent LOI over the range 0.1 to 0.9 per cent LOI. When allowance is made for the rms error in the ignition method, the error in the neutron method is found to be 0.07 per cent LOI.

Jan 1, 1985

The ore mined from the Lead Lode of The Zinc Corporation leases consists of a fairly granular mixture of galena, marmatite, chalcopyrite, tetrahedrite, pyrrhotite, pyrite, and lollingite with a gangue association of calcite, quartz, bustamite, rhodonite, mangan-hedenbergite, garnet, fluorite, mangano-calcite and apatite. The silver content of the ore occurs in three minerals tetrahedrite, dyscrasite, and pyrargyrite, the last two mentioned occurring in microscopic association only. Other metallic and gangue minerals are also present in this complex mineralogical association, but do not influence the milling operations.Fortunately, the silver minerals favour the galena and chalcopyrite as their host minerals, thus facilitating the recovery of both copper and silver in the lead concentrate. The ore from the Lead Lode assays from 14 - 18 per cent lead; 3.0 - 4.5 oz silver per tonne, and 9.5 - 12.0 per cent zinc.A parallel lode, known as the Zinc Lode, is well developed in The Zinc Corporation leases. This lode assays from six to eight per cent lead, 1.5 oz silver per ton, 18 - 25 per cent zinc with a siliceous gangue. The common Lead Lode gangue minerals, calcite, rhodonite, bustamite - are very rare in present underground exposures. No metallurgical work was done on this ore during the pilot plant operations.The aim in the milling process is to produce:1. A lead concentrate with the maximum economic recovery of lead, silver, gold, copper and antimony, and minimum zinc content.2. A zinc concentrate with the maximum economic recovery of zinc, cadmium, and cobalt, and minimum iron, arsenic and fluorine content.3. A waste residue containing sufftcient granular material to be utilised as underground fill.In considering the economics of the milling practice the above three requirements plus consideration of the tariffs submitted by the purchasers of concentrates were the deciding factors in the evolution of the present milling practice.Towards the end of 1924 The Zinc Corporation Limited added to and adapted the old zinc tailings plant for the treatment of 5000 tons of crude ore per week. This plant, which operated until January 1936, was in general principles similar to the standard Broken Hill methods of ore concentration, whereby the galena was recovered by the gravity concentration methods of jigging and tabling with selective flotation concentration of the residual galena and marmatite. One important difference from other Broken Hill plants was that the primary grinding of the jig tailing was performed with flint-loaded mills operating in closed circuit with revolving screens. Two primary grinding sections were installed, each consisting of two 5 ft diameter by 10ft long tube mills loaded with flint pebbles working in closed circuit with four 3 ft diameter by 3 ft wide revolving screens covered with 22mesh Toncap woven wire screen with 0.57 mm opening. Each section carried a circulating load of 28.3 tons per hour for a jig.

Jan 1, 1994

This paper will describe the exploration project which led to the discovery of the La Escondida porphyry copper deposit in northern Chile and will serve as companion paper to the description of the geology of Escondida being presented by J M Ojeda. The author would like to express his appreciation to Robert Hickman, Chairman of Minera Escondida, for permission to present this paper.In July 1978, a proposal was made by J D Lowell to Robert Wheaton, then Exploration Manager of Utah International, that Utah fund a "grass roots" program exploring for porphyry copper deposits in northern Chile. Wheaton expressed interest, and it was agreed that Getty Oil Co also be invited to participate. A joint venture agreement for the Atacama Exploration Project was signed January 1, 1979, between Utah, Getty and Lowell. The project was managed by Lowell who reported to a management committee which through most of the project consisted of Lowell, Francisco Ortiz, Robert Wheaton, Maurice Young, Sigfried Muessig and Louis Rove. Oliver Warin and Jim Bratt participated in the committee in the last phase of the contract. Special thanks are due Louis Rove of Getty and Maurice Young of Utah who made contributions throughout the course of the project. Francisco Ortiz was resident manager through most of the project.

Jan 1, 1990

Segregation studies in ternary systems of glass ballotini, iron ore and coke particles (with size range of 1-8 mm in each) in filling and emptying a laboratory size Paul Wurth hopper are described. In-bin segregation is shown to be a function of the position in the hopper, the nature of the material and the feed composition. The in-bin results are correlated by the equation C = C0k, where C and C0 are the size compositions (wt per cent) in the hopper and feed respectively, and k is an experimentally obtained segregation constant. The results of now pallern measurements show that material discharges from the hopper according to the sequence; core now - wall now - scaffold now, where the latter represents stagnant material at the hopper wall that discharges last. Size segregation in the discharge stream from the hopper is shown to be a function of in-bin segregation and hopper now pallern. A method of predicting discharge segregation from these two sets of data is suggested. The results of the model studies are also compared with industrial data and these show satisfactory agreement. Discussion of the hitherto ignored effect of size segregation on hopper now rates, stoppages and other operating problems is also included.

Jan 1, 1985

This paper presents results of the experiments carried out in Beth Energy No. 33 Mine for the purpose of alleviating problems associated with cutter roof. Cutter roof problems have delayed the advance of the entry development considerably and maintenance cost of these entries was very high due to the requirement of very extensive and heavy artificial supports. The study includes assessment of the problem, investigation of the geology and lithology of the mines, study of in-situ stresses and corrective measures to combat the problem. Two approaches were selected as the corrective measures: 1) implementing yield pillar concept in order to reduce the effects of in-situ horizontal stresses, 2) designing an effective roof reinforcement system and application procedure. Results of this study revealed that roof strata is weak and in-situ stresses are very high at the problem area which results in development of cutter roof. Implementation of yield pillar concept was found to be ineffective because cutter roof often developed at the entry face concurrent to the development. However, proper design and implementation of roof reinforcement system stabilized the roof and eliminated roof caving during both entry development and retreat of longwall face, despite existence of the cutter roof, at a much lower cost.

Jan 1, 1992

By P Bonniwell

As a part of the Newcrest, Telfer Expansion Project, a consortium of Australian, Canadian and South African Mining Contractors in joint venture have been contracted to develop the hoisting shaft. The parties namely; Byrnecut Mining Pty Ltd, Murray and Roberts RUC and Thyssen Mining Construction of Canada Ltd have combined their individual expertise to excavate the shaft. There is a particular emphasis on the use of proven shaft sinking techniques from North America and in particular integrating electric hydraulic drilling equipment and personnel from the Canadian Mining industry. The Telfer hoist shaft when completed will have a finished diameter of 7.1 metres and extend to a depth of 1170 metres below the collar. The shaft will be fully concrete lined and will later be equipped for hoisting ore from the Telfer deeps at a rate of five million tonnes per annum. The shaft when completed will be the largest shaft ever completed in Australia on a volumetric basis. This paper will examine the technical aspects of the shaft sink, as well as exploring the integration of personnel and equipment from the frozen prairies of Saskatchewan, Canada into an operation in the Great Sandy Desert of Western Australia. What are the spin-off benefits for the development of other shafts within Australia?

Jan 1, 2005

By Sneddon NW

Aberdare North Colliery is situated on the eastern boundary of the City of Cessnock in the Hunter Valley, New South Wales. Although the area is now noted for its wines and vineyards, the district has a long history based on coal mining. The richest coal seam in the Cessnock district is the Greta Seam, a low ash, high volatile steaming or gas making coal. The seam, up to 10 metres thick, extends over a large area surrounding the city of Cessnock and neighbouring townships such as Bellbird, Aber- dare, Kearsley, Neath, Ellalong, Kurri Kurri and Stanford Merthyr. The Aberdare Colliery, leases, which extend under Aberdare and Cessnock townships, were first worked in 1905 and continued developing pillar panels until the mine closed on 11 Nov- ember, 1960. Coal mining to this time consisted mainly of developing pillars to the 2.4 metre parting and, in some areas, dropping the top coal to the 6 metre parting, thus leaving the pillars intact, the top 1.8 metr-es of coal be- ing left untouched due to the high sulphur content. Aberdare North Colliery was opened in 1956 in order to recover and extract the pillar coal and tops left standing for over 40 years. During the pillar extraction phase the occurr

Jan 1, 1981

By Peck RC

The ore body at Elura contains fine grained galena and sphalerite in a matrix which is mostly pyrite. A differential flotation circuit concentrates lead and silver in the first section and zinc in the second. The lead section, shown in figure 1, was sampled in detail previously and the metallurgical performance assessed on a size by size basis. That assessment took no account of liberation and given the fine grained nature of the ore body, this could lead to an incomplete picture of the flotation performance. Liberation measurements were made using the QEM*SEM system on four size fractions of samples taken from seven different streams in the lead section. Using the mineral flows obtained from the mass balance around the lead section an excellent liberation balance was obtained which enabled the effect of liberation on the flotation performance to be assessed. The measurements indicated that only 17 per cent of the galena and 28 per cent of the sphalerite in the flotation feed was liberated. On the other hand 31 per cent of the gangue iron sulphides were liberated. The final concentrate was largely composed of locked galena and locked iron sulphides with 85 per cent of the product being locked. There was a small but significant fraction of liberated pyrite.

Jan 1, 1991

By Yao S, Wang P, Zhang C

The Zhilingtou Au-Ag deposit is situated in the eastern part of the complexly deformed and metamorphosed South China Caledonian Fold Belt. It consists of seven orebodies that are almost exclusively hosted by biotite plagioclase gneiss of the Precambrian Chencai Group. They form an apparent en echelon pattern in both cross-section and level plan. Three different ore types, based on mineralization textures, have been recognized within the Zhilingtou lode. These are Au-Ag-rich quartz veins, Au and Ag-bearing silicified rocks and Au-Ag-containing altered rocks with quartz stockworks. The mineralization is principally composed of electrum, argentite, pyrite and minor sphalerite, galena as well as traces of hessite and chalcopyrite plus a gangue assemblage of quartz, rhodonite, sericite and chlorite. Fluid inclusions related to Au-Ag mineralization yield a wide range of homogenization temperatures from 110 to 447¦C, with two distinctive peak values at 250-300¦C and 350-400¦C respectively. S30Si values of quartz veins and silicification from the three stages of mineralization range from -0.1 to -0.4%o. The mineralization at Zhilingtou is interpreted as forming by recirculated meteoric water extracting ore-forming elements from metamorphic rocks due to Mesozoic volcano-magmatic activity.

Jan 1, 1995

The discovery of economic uranium miner alisation in unique geological conditions at Yeelirrie, 700 km NNE of Perth, presented Western Mining Corporation Limited with a num- ber of sampling and evaluation problems. Carn- otite mineralisation occurred in a porous cal- crete-clay lithology in close proximity to the water table; background information on such a deposit was non-existent and sampling in these conditions could be difficult. The deposit was sampled initially by aug- er drilling with X-ray fluorescence analysis of drill cuttings, followed by reverse circulation and diamond drilling with analyses by X-ray fluorescence and gamma logging of the holes. Two costeans provided lithological and grade distribution data and mining experience in the deposit. Spoil from the costeans was stockpiled according to location in the first costean and according to location and grade in the second costean. Samples from the various stockpiles were analysed by X-ray fluorescence. No. 1 costean was extensively sampled by channel sampling of the walls and by pit sampling of the floor of the benches of the costean by back hoe. No. 2 costean was sampled by Geiger counters mounted in T-probes and by the gamma logging of auger holes to establish the valid- ity of the T-probe results. Samples were taken

Jan 1, 1976

By I M. Platten, Y Xie

Narrow vein gold mineralisation generally contains both fine (<100 ¦m) and coarse (>100 ¦m) gold particles. The in situ size and shape, deportment, distribution and abundance of the particles controls deposit sampling characteristics, grade distribution and metallurgical properties. Particles can range from individual disseminated grains, clusters of particles and masses above 1 cm in size. At each end of the coarse-gold to fine-gold spectrum, the samplability of a deposit ranges from relatively simple for fine-grained disseminated gold particles, through to extremely difficult for very coarse particles. Deposits generally show a background grade of mineralisation dominated by disseminated fine gold particles. Drilling will resolve the background grade well, though is likely to considerably understate the grade related to the coarser gold particles. Gold mineralogy has a significant impact on metallurgy, with key factors affecting recovery being particle size, deportment, liberation parameters and silver content of gold minerals. For coarse gold particles the focus should be on liberation and the early removal of the particles from the mill circuit by gravity concentrators and gold traps. Finer particles will require more grinding to liberate prior to flotation or cyanide extraction. The determination of gold particle sizing is thus required to minimise evaluation and geometallurgical uncertainty and lower project risk.

Jan 1, 2008

By Dobos K

The Clermont Goldfield, from which about 300,000 oz of bullion have been extracted, was one of the major gold producers in Queensland. This paper is derived from a systematic study of the mineralogy, geochemistry, and stable isotope geochemistry of the deposit, based on detailed field work and logging of 57 reverse-circulation percussion drilling holes at the Black Ridge Gold Deposit (Fig 1), aimed at addressing the long debated question of gold-ore genesis at Clermont, i.e., whether it is of fossil placer or hydrothermal origin.Detailed petrologic and mineralogical studies indicate the hydrothermal alteration at Black Ridge is dominated by extensive siderite (+rhodochrosite-ankerite) veinlets and stockworks, which are concentrated along the deformed unconformity between the Anakie Metamorphics and basal conglomerates of the early Permian Blair Athol Coal Measures. Siderite alteration is also moderately developed in all other rock units represented at Black Ridge, including the Tertiary basalt. Weak to moderate phyllosilicate alteration is common throughout the deposit, including chlorite-sericite along the shear zone of the unconformity, and sericite-clay in the conglomerates. A sulphide-oxides zonation also has occurred, including pyrite below the unconformity, (pyrite)-chalcopyrite-marcasite-(hematite) along the deformed unconformity, and marcasite (hematite, pyrite) in the conglomerates.

Jan 1, 1990