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The equipment and general smelter layout for the Mount Isa Copper Smelter were designed by engineers associated with the American Smelting and Refining Company and by Mount Isa staff engineers. The final notice of site was dictated by the need for 'building the smelter near the existing Mount Isa power house to enable full use to be made of the steam from the waste heat boilers. Although much excavation work was necessary before concrete foundations could be poured, the location lends itself to further expansion should it become necessary. The plant is designed and constructed to involve straight line smelting operations which include the following major steps in the overall scheme.1. Charge make-up.2. Roasthig.3. Reverberatory smelting.4. Converting.5. Refining.6. Casting.CHARGE MAKE-UPA system of proportioning bins is provided for preparing the feed mixture for the roasters, Sulphide concentrate containing 24% copper wiil be delivered by belt conveyor from the filter plant to the smelter storage patio. This is a large roofed concrete floor that provides a maximum storage capacity of 8,000 tons of concentrate. Eight proportioning bins located below but adjacent to the south end of the patio will be used for actual charge make-up from which concentrate, ore and flux will be proportioned to the feed belt and conveyed to the roaster feed hoppers. Four of the proportioning bins, 80 tons capacity each, will receive...

Jan 1, 1953

In the Massif du Sud ophiolite complex platinum group elements occur predominantly as ultrafine-grained inclusions of rutheniridosmine, laurite and iridosmine. These form primary inclusions less than 5 to 10 um in diameter within chromite in podiform chromitite fringed by dunite, and emplaced subsequent to solidification of the host harzburgite. There is no specific association with trace inclusions of transition metal sulphides. The crystallization of then: Ir. Os and Ru minerals may have occurred concomitant with hromite, perhaps related to more reducing conditions produced by crystallization of the chromite. The Ir, Os. and Ru show pronounced fractionation from Pd, Pt and Rh expected to be also present in the mantle source rock. The dunite shows evidence of metasomatic origin from adjoining harzburgite, and the possibility of selective crystallization of the Ir sub-group elements suggests that Pd, Pt and Rh may have been transported elsewhere.

Jan 1, 1989

By Locke CA

Geophysical signatures of the Taranaki and Tongariro volcanoes reflect similarities in their age, composition and hydrothermal histories, but also reflect differences in host rock settings and edifice evolution. The Taranaki volcanoes have strong positive gravity anomalies showing that their edifices largely consist of dense andesite which reflects substantial lava production or dyke injection during construction and that large sub-edifice dykelstock complexes occur. In contrast, the Tongariro volcanoes have strong negative gravity anomalies indicating low density edifices of volcaniclastic material; no sub-edifice intrusions can be identified, probably because of the lack of density contrast with host basement rocks. Strong positive magnetic anomalies over the younger cones can mainly be attributed to near-surface andesite lavas or dykes whereas subdued magnetic effects are associated with hydrothermally altered zones within both edifices and sub-edifice intrusions.

Jan 1, 1995

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

Gold mineralisation at the Kerimenge-Lemenge prospects is a classical example of myltiple, overprinting events, associated with intrusive-related hydrothermal systems. Repeated emplacement of high level dacitic porphyry bodies (Edie Porphyry; 2.4 - 3.8 Ma) was accompanied by a phreatomagmatic eruption which formed a diatreme-maar complex. Later hydrothermal fluids utilised permeable fault zones and diatreme contacts. Mineralisation took place during two main events. Stage I consists of early quartz - illite/sericite - carbonate phase with associated pyrite-arsenopyrite mineralisation. This phase is zoned from quartz - sericite-pyrite/arsenopyrite in the south at depth, to dominantly manganocarbonate - illitic clay - arsenopyrite- pyrite_s significant base metals in the north and at shallow levels. The majority of known gold (18.1 Mt @ 2.0 g/t Au) at Kerimenge is associated with Stage I activity. The gold occurs primary within the lattice of the sulphides and is metallurgically refractory. Fluid inclusion studies indicate early boiling and progressive cooling and dilution of hydrothermal fluids during the evolution of the Stage I event. Near paleosurface condensation of gases, which evolved off the boiling system at depth, produced abundant low pH bicarbonate fluids. During the waning phases of Stage I activity, these bicarbonate condensate fluids descended down permeable structures and formed banded manganocarbonate veins. High grade non-refractory gold mineralisation during Stage II event is restricted to favourable structures at relatively shallow levels and in the northern regions of the prospect area. Gold in this event exhibits a distinctive Au - Ag - Te -Cu geochemical signature, and is associated with hessite - tennantite - chalcopyrite mineralisation within quartz veining. Alteration and fluid inclusion studies indicate that this style of mineralisation is a result of the quenching of pulses of hot, late magmatic mineralised fluids by the cold condensate waters.

Jan 1, 1997

This paper shows how small calculators can be used for ball mill simulations. Two calculations are examined, the first to calculate the mill parameters and the second to predict the mill product. In the case of small programmable calculators the programs for two common models are given.

Jan 1, 1976

By Dunlop G. A, Cantrell R. A

The metallurgical and engineering requirements that form the basis for planning column flotation Pilot Plant testwork are reviewed. Pilot plant operating issues are discussed and a basis for the testwork program formulated. The application of the testwork results to engineering design and scale-up is briefly reviewed.

Jan 1, 1992

By Ingham PD

Selection of equipment for a mining operation, such as Mount Isa Mines, requires certain parameters to be correctly defined. Management control is essential for monitoring, improving and future purchase of equipment. Some research is being done independent of supply manufacturers. Observations about future outlook are made.

Jan 1, 1982

A narrow (200-300m) zone of amphibolite facies metamorphic rocks underlies the Papuan ophiolite near the Musa-Kumusi divide, SW of Popondetta, Oro Province. The amphibolite rocks are bounded up-section, to the NE, by peridotite and gabbro of the ophiolite; and down-section, to the SW, by mafic greenschist, which in turn overlies blueschist facies mafic schists of the Emo Metamorphics.Amphibole compositions within the narrow contact zone show a strong chemical zonation which reflects a steep thermal gradient, with maximum temperatures >800¦C at the peridotite contact. The zonation is recorded in Ti content and A-site occupancy, relative to Al'¦

Jan 1, 1994

By J Centofanti, D Conti, R Riske, C Morley, A Cook

Why is it so difficult? Why are there differences throughout the resources industry in how reconciliation factors are reported and calculated? Why is there no standard formula to use? These are common questions asked when mining companies try to compare reconciliation results across operations or attempt to undertake internal or corporate governance reporting processes. For many mining companies the calculation of reconciliation factors is often a very time and resource intensive part of mandatory reconciliation reporting. Some major mining companies, that move millions of tonnes of material per annum, dedicate full time resources to the calculation of reconciliation factors. The willingness of these companies to set aside resources demonstrates the value that operations place on good reconciliation reporting. Reconciliation is about measuring the variance between two like measures at different points along the mining sequence. It can be undertaken between predictive models, forecast plans and actual measured performance. Calculations are used to derive a variance between two sections within the mining sequence, with the result being commonly known in the resources industry as a æfactorÆ. Mining companies use the calculation of reconciliation factors as key performance indices (KPIs) to provide a æhealth checkÆ of their operation, with variances often pointing to issues either with the accuracy of the original estimate or the quality of the measurement being used in the comparison. There are many reconciliation factors that can be calculated and reported. This paper will set out, clarify and provide a recommended standard means of calculating each specific factor that, where adopted by a company, will ensure compliance with the international reporting codes, such as JORC. Using case studies from Rio Tinto Group (Rio Tinto) and BHP Billiton Mitsubishi Alliance (æBMAÆ), and the authors experience across a wide range of mine sites, the outline of a generic solution for tracking a parcel of material from the pit through to the port along with appropriate reconciliation factors is provided. The intention of proposing standardised reconciliation factor terminology and methodology is to provide the foundations of a system to enable communication and comparison across different commodities, companies and mines sites.

Jan 1, 2009

By D Schwab, R M. Tosdal

The Quesnell-Stikine arcs, in the Canadian Cordillera, are host to Triassic and Early Jurassic alkalic porphyry Cu-Au and calc-alkalic porphyry Cu-(Mo-Au) deposits formed outboard of ancestralNorth America in island-arc tectonic settings (McMillan, 1991). The majority of the alkalic porphyry Cu-Au deposits are products of a discrete magmatic event at the end of the Triassic, with a second and smaller event in the Early Jurassic (Mortensen, Ghosh and Ferri, 1995). Of the Triassic complexes, the Galore Creek alkalic intrusive suite is one of the largest and most silica-undersaturated intrusive complexes, and host to the most significant undeveloped alkalic porphyry Cu-Au resource in North America (Lang, Stanley and Thompson, 1995). Because of the common presence of feldspathoidal-bearing rocks in the complex (Enns et al, 1995), Galore Creek likely represents an end member example of the alkalic porphyry Cu-Au class. The Galore Creek alkalic Cu-Au-Ag porphyry district, located in NW British Columbia (Canada), contains 12 mineralised prospects (Enns et al, 1995; Micko et al, 2007; Schwab et al, in press) with a total measured and indicated resources of 785.7 Mt at 0.52 per cent Cu, 0.29 g/t Au and 4.87 g/t Ag (NovaGold Resources Inc, February, 2008). The Central Zone is the largest and best delineated. Other economically important mineralised centres include the South-West, Bountiful, West Fork and Junction deposits. The South-West Zone, the focus of this contribution, is a Cu-Au-Ag breccia-centred deposit with a measured and indicated resource of 69 Mt grading 0.42 per cent Cu, 0.69 g/t Au, 2.67 g/t Ag. Hosted in brecciated intrusive rocks, the South-West Zone is distinctly younger than the Central Zone and most of the other mineralised centres (Enns et al, 1995; Schwab et al, in press). The South-West Zone therefore preserves the late stages of hydrothermal evolution at Galore Creek. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By T Lancaster

The Mount Gordon operation, consisting of the Esperanza open cut mine and the unique Mount Gordon Ferric Leach processing plant, is operated by Western Metals Copper Ltd at Mount Gordon, 125 km north east of Mt Isa. The processing plant treats predominantly the secondary copper sulphide minerals, chalcocite and covellite. The gangue consists of massive pyrite and a range of silicified siltstones. The processing plant utilises a conventional single stage SAG/cyclone milling circuit, followed by low-temperature/low-pressure autoclave oxidation to produce copper in solution. The pregnant leach solution is treated via conventional SX/EW technology to produce copper cathode. Currently the plant is operating at a nominal production rate of 48 500 tpa copper. The Mount Gordon Ferric Leach technology is the worlds first integrated pressure leach/SX/EW process to be used to treat copper sulphides on a full plant scale. In the last six months, July to December 2001, the plant has emerged from a two-year postcommissioning phase to achieve steady state operation. This has been characterised by high plant availability and consistent production performance in excess of the name plate capacity of 45 000 tonnes. Production rates will continue to increase over the next 12 months to over 50 000 tpa via a planned process of incremental improvements. The pressure leach circuit has consistently achieved availabilities exceeding 95 per cent over the past 18 months. Notwithstanding this, the leach circuit still has a much greater requirement for planned maintenance than SX/EW. For much of the Mount Gordon processing plantÆs operating life, the leaching process has constrained production. Recent developments arising from detailed mass and energy balance modelling have now significantly improved leach capability, resulting in the plant bottleneck being shifted to electrowinning. In order to balance the capabilities of the two circuits however, the surge capacity between leach and SX/EW was increased substantially. This effectively de-coupled the higher capability but lower availability leach circuit from the lower capability but higher availability SX/EW circuit. As a result, electrowinning utilisation has increased to in excess of 98 per cent, which is reflected in a higher overall plant throughput.

Jan 1, 2002

The large, high grade 3000 and 3500 copper orebodies at Mount Isa lie greater than 1200 m below the surface, and partly beneath the silver-lead-zinc mining operations at the Isa Mine.Since discovery over 30 years ago, the primary data acquisition programs have been integrated with long-term copper production strategies. These potentially sizeable and distinctly separate accumulations of copper mineralisation are the only sources capable of supplementing a decline in output from the 1100 orebody in the 1990s. Within a decade these deeper copper orebodies will become the major source of copper ore.

Jan 1, 1993

By Price B. D, Staunton W. P

The Mineral Science Laboratory of the Government Chemical Laboratories has recently investigated various procedures for the analysis of the platinum group metals (PGMs). This investigation covered a number of methods for the extraction and preconcentration'of the PGMs from a wide range of geological materials. The nickel sulphide extraction technique proved to be overall the most applicable procedure. Flame atomic absorption spectroscopy (FAAS), electrothermal atomisation atomic absorption spectroscopy (ETA-AAS), inductively coupled plasma atomic emission spectroscopy (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS) were examined for their suitability in analysing platinum group metals in solution. ETA-AAS and ICP-MS proved to be the instruments of choice due to their low detection limits.

Jan 1, 1987

Examples are given of the different management approaches used to improve a mine's profitability and the view is put that attention to mine design is very important but easily overlooked. The need for humans to use graphics to ccanprehend and develop strategies to exploit ore deposits is discussed. The use of two and three dimensional representations for geology, mine design and survey data is reviewed. The current use of computers in mining is discussed and reasons for the limited use of ccanputer graphis are proposed. Suggestions are made as to how more extensive use may be made of catputer graphics in mining by using recent and possibly forthcoming advances in computer hardware and by adopting certain software approaches.

Jan 1, 1983

Although giant strides have been made in the Australian mineral industry over the past quarter of a century in terms of mineral discoveries, self-sufficiency of commodities, contributions to exports and other aspects, there are unhealthy signs emerging which require attention. For instance there are 20 out of 34 discoveries of base metals, uranium and nickel which for a number of reasons await development. Some of the reasons for the standstill in the mineral industry are partly economic, partly due to competing land use, uncertainty in applying or, recognising the principle of crown ownership of minerals, and to some extent lack of appreciation of two closely related exploration activities referred to as development exploration and assessment Exploration.

Jan 1, 1979

A simple and rapid method for delennining gold and silver in carbon samples is described. The method involves dissolution of carbon ash in a strong oxidising medium of aqua regia and hydrofluoric acid. Gold and silver are determined in the resultant solution using atomic absorption speetrometry (AAS). The method is efficient and reproducible. Gold results are comparable to the standard fire assay results, with agreement of results within ± 5 per cent. The co-efficients of variation for gold and silver are 0.37 and 0.39 per cent respectively for six replicate analyses. The analysis of gold and silver in a batch of ten carbon samples can be completed in approximately four hours.

Jan 1, 1992

Hindustan Zinc Limited has successfully installed an In-Stream Analysis and Process Control System in the flotation section of the Balaria Lead-Zinc concentrator at Zawar Mines. The system comprises In-Stream Analysis to continuously monitor lead and zinc levels in feed, concentrates and tailings streams, field instrumentation for reagent distribution and flotation cell level control linked to a central Distributed Control System for supervisory control functions. An intensive training scheme was conducted by the system supplier for concentrator metallurgical and instrumentation engineers. Since commissioning of the system in April 1989, Hindustan Zinc has enjoyed the benefits of improved lead, zinc and silver recoveries, improved concentrate grade control and reduced reagent costs.

Jan 1, 1991

Longwalling has reached a high standard both in Germany and Australia and most improvements should be expected in planning, monitoring and control. Double drum shearer have electric drives to 1000 kW and automatic height control is under development. Conveyor pans to 40mm thickness and chains to 2300 kN breaking load are in use with controls for pretension and load compensation under test.Trends in support are towards two leg shields with loads to 3850 kN per leg and electrohydraulic controls. Expert systems have been devised for planning and diagnosis tasks. With increases in technical standards, staff qualification standards at rising too, drawing attention to training requirements for modem personnel.

Jan 1, 1991

By Canning RL, Pritchard J

The surface treatment works in the Mount Isa Mines Limited copper stream consist of a concentrator and smelter with annual capacities of 5.6 million tonnes of ore and production of 155 000 tonnes of anode copper respectively. Both plants have been sites for process optimisation in recent years, the emphasis being to achieve productivity gains in each particular plant. The continued low real world prices for copper resulted in an in-depth review of the entire copper process stream. This indicated the need for developments within both the concentrator and smelter, and changes to operating strategy to ensure that the entire treatment stream could be optimised. The paper reviews these changes.

Jan 1, 1986