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In line with mining operations throughout Australia, Western Mining Corporation Limiter' is striving to increase productivity by intro-ducing mechanized mining techniques wherever possible. Kambalda Nickel Operations' (K.N.O.) largest operating nickel mine, Long Shaft, is currently introducing mechanized cut and fill methods which must provide flexibility to cater for an orebody that variesconsiderably in width, both along the strike and up dip.This has resulted in modifications to the previous approach to primary level develop-ment, and intermediate stope development, and in the type of development and production equipment being employed. Electric-hydraulic diesel jumbos and diesel loaders have now been mated with conventional rail equipment and production airtrack machines are being utilized.The transition to mechanized methods is in its preliminary phase and is being monitored closely to ensure any productivity gains are not offset by a substantial drop in mine grade. The precise method ofmechanized mining has not been finalized and selective methods will be used, according to the ore width and ground conditions, which vary throughout the mine.

Jan 1, 1985

The Rate Variable Batch Test (RVBT) - A Research Method of Characterising Ore Floatability

Sep 13, 2010

By T Albinson

Mexican epithermal deposits can be broadly grouped into two types based on their contained metals, distribution, associated igneous rocks and fluid inclusion compositions. Silver-gold deposits (eg Tayoltita) mostly occur in the western part of northernMexico where host rocks consist of Eocene, intermediate composition volcanic and intrusive rocks; fluid inclusion studies indicate that mineralising fluids were <300¦C and dilute (=3 eq. wt. % NaCl). In contrast, silver-lead-zinc deposits (eg Fresnillo) mostly occur in the central part of northern Mexico where they are temporally associated with Oligocene-Miocene volcanic rocks and intrusions of felsic composition, but commonly hosted within underlying Paleozoic-Mesozoic sedimentary rocks; fluid inclusion studies indicate that mineralizing fluids ranged from 200 to 400 ¦C and were saline (=10 eq. wt. % NaCl). The distribution of these two deposit types, crosscutting major crustal sutures, and the close spatial-temporal relationships between mineralisation and magmatism, together suggest that magmatic processes were more important in the formation of mineralising solutions, as a source of both ligands and metals, than the segments of crust hosting deposits.

Jan 1, 1995

Scale build-up in titanium palladium alloy spent electrolyte heat exchangers in the residue treatment plant commissioned at Risdon, Tasmania in 1971 was shown to be a mixture of manganese dioxide and anhydrite (CaSO4). The manganese dioxide was deposited as a result of thermal decomposition of permanganate ions present in the spent electrolyte. It was shown that deposition of manganese dioxide and associated anhydrite scale could be prevented by prior reduction of permanganate ions to the manganous (Mn++) state by the addition of ferrous ions. In the plant this was conveniently accomplished by injecting into the inlet line to the heat exchangers sufficient zinc plant solution containing ferrous sulfate to decolourise the spent electrolyte. This action prevented deposition of such scale for another 21 years, until the heaters were finally decommissioned in March 1992. Measurements indicated that addition of the reducing solution lowered the anodic potential of the titanium alloy by 200 - 300 mV (depending on the solution resistance), but that it was still +300 to 400 mV with respect to a standard calomel electrode. It was shown that, if necessary, a small impressed current could be applied to provide anodic protection. Before scale deposition was overcome by the addition of ferrous sulfate solution, badly scaled heat exchangers were cleaned by recirculating a solution of hydrogen peroxide in spent electrolyte or dilute aqueous sulfuric acid, after laboratory testing of a variety of possible solvents for the scale. Corrosion tests indicated that attack on the titanium alloy by the acidic peroxide cleaning solution was insignificant.

Jan 1, 2005

Five types of mineral resource were known in the sedimentary cover of the oceans and seas floors prior to the 1980s: 1. hydrocarbon fields including some very large zones of oil and gas accumulation; 2. æRed SeaÆ type thermal oozes with increased concentrations of noble metals; 3. ferromanganese nodules; 4. concentrations of metallic sulphides (æBlack SmokersÆ); and 5. cobalt-bearing ferromanganese crusts on the summits and slopes of seamounts.   Since then, the so called æWhite SmokersÆ, containing sulphides of copper and zinc, have been discovered. The ore horizons (manganese, copper, nickel and other metals) of the sedimentary cover of deep-sea basins comprise a sixth type of mineral resource in the oceans. These horizons have not only a theoretical, but also a principal economic significance.

Jan 1, 1995

By Forssberg E

This paper presents the experimental results on the effects of slurry Theology on ultra-fine grinding by a stirred ball mill. The amount of dispersant, slurry density and the particle size were selected as the parameters. The viscosity of dolomite-water slurry was measured by rotational viscometers. It was found that by adding enough dispersant, the effect of particle size from 1 to 10 pm on the slurry theology could be eliminated, but a strong effect of slurry density (tested for a range of 65 to 75 wt per cent) remained. The use of dispersant transformed the slurry from Bingham plastic flow to dilatant flow, which reduced the yield stress to zero, but increased the viscosity at higher shear rates. During the milling process, the viscosity was stable. The yield stress, however, increased suddenly from zero after a certain milling time. The mill operation stopped at the point where the yield stress increased due to poor slurry fluidity. The milling efficiency was found to be higher at a lower amount of dispersant addition or a lower slurry density within the experimental limits.

Jan 1, 1993

The latent conditions clause in various general conditions of contract have traditionally proved to be a source of significant disputes in tunnelling contracts, even when extensive geotechnical investigations have been carried out at the tunnel site and a report of these investigations provided with the tender documents, informing the contractor of the nature and extent of subsurface conditions likely to be met with during execution of the works. This paper discusses the contractual aspects of the new latent conditions clause in the recent Australian Standard AS 2124-1986, General Conditions of Contract, in relation to tunnelling contracts. A comparison of this new clause is made with other latent conditions clauses in general conditions of contract in use in Australia and other commonwealth countries. It is seen that the new latent conditions clause in the recent Australian Standard 2124-1986 has, by providing for a reasonable apportionment of risks, attempted to minimize contractual disputes relating to latent conditions in tunnelling contracts and to provide a satisfactory basis for quick and efficient settlement of such disputes should they arise during execution of these contracts.

Jan 1, 1987

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

The Tom, East and West zone, stratiform Zn-Pb-Ag deposits at Macmillan Pass, Yukon, Canada were discovered by Hudson Bay Mining and Smelting Co Ltd prospectors in 1951. Further exploration, including two phases of underground exploration produced an HBM&S calculated reserve of 9.28 Mt of 7.5 per cent Pb, 6.2 per cent Zn and 69.4 g/T Ag for these zones. Cominco Ltd optioned the property in 1988. Deep, surface drilling extended the West and Southeast zones downward 200 - 300 m, indicating an additional potential resource of several million tonnes of good grade. The magnitude of the controlling syndepositional setting suggests that mineralisation continues to greater depth but with increased drilling and possibly mining costs. The 30 x 60 km Macmillan Fold belt trends WNW across the NW Selwyn Basin and Cordilleran trend. Within the fold belt, the Central Block - a complex, rift controlled basin of Devonian siliciclastics, hosts seven zones of Pb-Zn-Ag mineralisation clustered about four hydrothermal centres. The centres, distributed over 24 km, are coincident with small syndepositionally active structural sub-basins. The Tom deposits, in one such sub-basin, are localised by a third order structure consisting of two palaeobathymetric troughs flanking a syndepositional horst. This structure caused drastic facies and thickness changes over 600 metres of strata and focussed the venting of hydrothermal fluids through permeable conglomerates in the horst and its flanking growth faults. Mineral facies are zoned, with Pb-Ag contents rapidly diminishing outward from the vent resulting in restricted areas of high grade Pb-Zn-Ag-Ba ore within more extensive, sub-economic, Ba-Zn mineralisation. Widespread iron carbonate alteration of the footwall and high Si, B and Zn values in the hangingwall 'fingerprint' the deposit and along with the distinct facies variations provide aids to exploring the Tom and like deposits.

Jan 1, 1993

By Veloso L, Alvarez O, David D

Cerro Colorado operations The Cerro Colorado Mine is located 150 km east of Iquique in the Atacama desert of northern Chile. The mine is wholly owned by Rio Algom Limited of Canada and produces copper metal using a bio leaching process. Tw

Jan 1, 1998

The author presents various procedures for the choice of dri-ving systems for mining, including the method of indeterminate Lagrange factors and linear programming.The possible application of the points-awarding method is demonstrated.It allows for taking into account both surd and commensurable characteristics of a driving system for mining. Also, the method of economic efficiency factors is outlined.All these methods make possible the best choice of a driving system, from the as-pect of electric energy saving. Two examples are given.

Jan 1, 1985

By M Magee, D Way

The Mount Isa Copper Concentrator was commissioned in 1973. In 1991, two autogenous grinding mills were installed replacing two stages of crushing, one stage of rod milling and one stage of primary ball milling. The cyclone overflow P80 of the secondary ball milling circuit was reduced to 120 microns due to the increased operating power in the AG/SAG mill circuits. A study of the mineralogy of the milled products and the plant flotation recovery indicated that the installed secondary grinding energy was more than what was required for adequate liberation of the chalcopyrite and half of it had potential for more effective use elsewhere. Halving the secondary grinding energy meant only one of the two secondary ball mills would be needed. The predicted saving in operating cost of one less ball mill was more than two million dollars per annum. This paper summarises various plant trials that were conducted in the Copper Concentrator to decommission one of the two secondary ball mills.

Jan 1, 2004

Technical disputes, commercial negotiations and workplace/societal conflict are a natural part of doing business and just living itself. Conflict is everywhere û at home (between family and neighbours); in the workplace (between management, co-workers and unions), with contractors and with other companies; and everywhere at the community level, dealing with land access (pastoralists/farmers and indigenous/First Nation people), environmental protestors and NIMBY-ites - Civil Society in general. Exploration and mining companies, operating in more remote, less developed and culturally diverse regions, tend to encounter myriad areas of conflict (typically emotion-charged) and they are outlined. Dispute prevention, management and various binding and non-binding resolution techniques are discussed. The paper gives a general overview of the ADR nomenclature and framework (mediation, conciliation, expert determination, adjudication, arbitration and litigation) encouraging technical professionals to participate. Its thesis is that lawyers should not necessarily be the first port of call when problems arise between the mining workforce, contractors, joint venture partners, purchasers of prospects/mines, traditional land owners, protest groups, etc. If the matter must be litigated, the role of the expert witness is critical in pretrial planning, negotiations, mediation and litigation management, so a few guidelines are provided. Whilst dispute resolution has a legal context, the paper is written from an AusIMM technical professionalÆs perspective, emphasising practical long-lasting pragmatic solutions.

Jan 1, 2006

The effect of conditioning energy input on the metallurgical results of an emulsion flotation process has beenattributed by previous authors to a detergency process.This paper shows that such a process does not explain the data and that an attrition mechanism is more appropriate.

Jan 1, 1970

INAP was formed in 1998 by a number of major mining companies, with a view to sharing acid rock drainage knowledge and experience, and to coordinate global research on the management of sulfidic mine wastes. INAP is now moving to further strengthen its global role by networking with regional organisations that are active in the area of ARD, including MEND 3/NEDEM 3 in Canada, the ADTI in the USA and ACMER in Australia. The INAP-Regional Organisation partnership will be formally launched at the 6th ICARD.

Jan 1, 2003

By D Bradshaw

The recovery of molybdenum at Kennecott Utah Copper (KUC) has become increasingly important as its demand and price have risen dramatically in the last few years. Consequently, the flotation behaviour of the molybdenum bearing mineral, molybdenite, has received a significant amount of attention. The flotation performance of molybdenite generally lags that of the copper sulfide minerals and is much more variable. There are many factors including particle size, liberation, surface slimes and oxidation that contribute to this and also much speculation as to the relative contribution of each of these factors. This paper discusses the morphology of the molybdenite found at KUC, the mineral associations in the different lithogical ores types and the effect that each of these has on flotation performance. Quantitative mineralogical analysis and an assessment of particle shapes are used to explain that flotation behaviour does not necessarily follow expected trends and that some behaviour is counter-intuitive. This unique behaviour can be explained by the morphology and anisotropic nature of molybdenite.

Jan 1, 2008

By Channon W, Dube M, Makwana M, Kerfoot D. G

In early-1995, the Bindura Nickel Corporation commissioned a pressure leach plant at its Smelter and Refinery complex located in Bindura, Zimbabwe. The novel pressure leach process was developed by Sherritt to treat the nickel-copper sulphide residue produced from the original atmospheric leach circuit. The process extracts essentially all the nickel from the nickel-copper sulphide residue under non-oxidising acid pressure leach conditions, thereby producing an upgraded copper sulphide residue suitable for smelting and refining to electrolytic copper. The commissioning of the pressure leach plant was relatively smooth and design conditions were achieved within six weeks of operation. This paper presents a brief description of the process development and the plant design, followed by highlights of the plant start-up activities and summary of the plant performance.

Jan 1, 1996

By C V. Putnis, T Geisler, A Putnis

In nature, ilmenite (FeTiO3) undergoes weathering through oxidation and removal of Fe to form an apparently continuous series of compositions from ilmenite to pseudorutile (ideally Fe2Ti3O9), and with further weathering, to leucoxene. To determine the mechanism of acid-leaching of ilmenite to ultimately form rutile, we have carried out an experimental study of ilmenite alteration in autoclaves at 150¦C in HCl solutions. Resulting products were studied by X-ray diffraction, scanning electron microscopy, electron microprobe and Raman spectroscopy. In some experiments the solution was initially enriched in 18O and the distribution of the isotope in the alteration products mapped from the peak shift in the Raman spectra. The results indicate that the alteration may proceed in two stages, each with a sharp interface between the parent phase and the product. The alteration begins at the original ilmenite crystal surface and along cracks through which the fluid can migrate. The first alteration product is pseudorutile û no phases intermediate between ilmenite and pseudorutile were detected. The textural relationship between ilmenite and pseudorutile suggests a coupled dissolution-reprecipitation mechanism rather than a solid state continuous oxidation and Fe diffusion mechanism. The second stage involves a further dissolution-reprecipitation step to form rutile. Raman spectroscopy shows that the 18O is incorporated in the rutile during the recrystallisation. Throughout the alteration process the original morphology of the ilmenite is preserved although the product is highly porous. The rutile inherits crystallographic information from the parent ilmenite, resulting in a triply-twinned rutile microstructure.

Jan 1, 2008

By Kilgour I

The installation of a final cleaning column at Ok Tedi Mining Limited was carried out to increase final concentrate grade in order to reduce concentrate handling, shipping and treatment charges and to reduce penalty payments. To fast-track the project a decision was made to install a full-size column on one of the two parallel circuits, designed on information readily available and utilising the experience of mill staff and an engineering consultant, rather than delay installation while a pilot scale program was conducted. A 3.66 m diameter by 12.8 m high column was installed to produce 40 t/h of final concentrate from a combination of rougher concentrate and recleaner concentrate. The column design and sparger system were by Cominco Engineering Services Limited.

Jan 1, 1991

By Stevens LG, Mok JK

With the long lead time requirement for engineering and construction of mineral pro- cessing facilities and the costly financing arrangements necessary, effective project management is essential to the successful and timely start up of these major production units. An added complexity is the frequently remote location of such projects and the demands this imposes on efficient project staffing, scheduling, logistics and cost control. Parsons recent experience with major projects such as Greenvale in Queensland and La Caridad in the desert of Northern Mexico and at remote locations like Sar Cheshmeh in Iran are described. The applications being developed for improving project controls through the use of computer techniques such as MSCS-COPES, and readily accessible and versatile transportation means are reviewed.

Jan 1, 1981