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By S A. Prevec

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Traditional models employed to genetically link associated chromite and platinum-group elements have favoured crustal contamination as the primary process for inducing sulfide and oxide saturation. The association of chromite ores with crustal contamination is well established in the literature. However, in the 1970s (cf Irvine, 1973, 1975), Irvine demonstrated that crustal contamination was in fact problematic as a tool for inducing chromite precipitation in mafic to ultramafic magmas. His results are re-examined here, along with some attempts to reconcile them with the effects of adding Fe to the models. It is concluded that crustal contamination is indeed problematic based on phase relationships alone. However, the role of fluids as a compensating agent is evaluated, which may explain why crustal contamination may indeed facilitate oxide and sulfide precipitation.CITATION:Prevec, S A, 2015. Chromite and platinum-group elements coprecipitation by crustal contamination or magma mixing revisited – genetic and exploration implications, in Proceedings PACRIM 2015 Congress, pp 311–316 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By C Balci, D Tumac, A Sheterpour-Mamaghani, E Dogan, A Kocbay, T Erdogan, A Gumus, H Copur, E Altintas

Excavation of vertical and/or inclined shafts in the underground structures requiring careful design and planning. Raise Boring Machines (RBMs) are commonly used for excavation of shafts for different purposes such as ventilation, orepass, and human-material transportation. Proper selection and accurate performance prediction of RBMs are two main parameters affecting the cost estimation and planning/scheduling. Indentation test is one of the most preferred methods that can be used to predict advance rate of RBMs. This study aims at suggestion of new prediction model for instantaneous penetration rate of RBMs based on indentation tests. Different rock (core) samples (with different geological origins) are obtained from the raise boring application projects in Turkey; then, the indentation tests are carried out on them by using a real-life insert (button), which is used in reamerhead cutters investigated in this study. Finally, the statistical relationships between the field performance and the indentation indices are investigated. The study indicates that the brittleness index (the ratio of maximum applied force to corresponding penetration) can be used to predict instantaneous penetration rate of RBMs used in the vertical raise bored shafts excavating rocks having uniaxial compressive strength lower than 100 MPa.

Nov 29, 2022

By J Butler, N Patel, S Narendranathan, S Rastogi

The Yallourn Mine (YM) commenced mining of brown coal in the 1920s under operation by the State Electricity Commission of Victoria (SECV), prior to it becoming privatised in 1996. The present owners of the YM, Energy Australia Yallourn (EAY), acquired the site in 2000 and intend to continue operations until scheduled closure in 2028. Brown coal extracted from the YM is fed into the Yallourn Power Station which supplies approximately 22 per cent of Victoria’s electricity. Water within the YM is collected and stored in the Township Field Fire Service Pond. Water levels within the Fire Service Pond (FSP) may fluctuate considerably depending on the requirement for storage at the site. With due consideration to the stability performance of mine batters adjoining the FSP, the authors performed slope stability assessments to evaluate the risk and consequence of batter instability during the potential pond filling as it approaches the ‘critical pool’. The critical pond is defined as the level at which the driving forces (destabilising forces) are at their greatest and the resisting forces (lake forces, friction) are at their lowest. This assessment was undertaken using the Mine Geotechnical Risk Index (MGRI) approach.

Aug 2, 2023

By R Valenta, A Littleboy

Geological heterogeneity is one dimension of complexity in mining. Significant effort is put into developing an understanding of this complexity so it can be used in resource estimation, mine planning and economic modelling. However, over the decadal lifespan of a mining venture, many other dimensions add to the complexity of a mining operation. These include: technological evolution, market fluctuations; investor confidence; social norms; local expectations; and ecosystem functionality. As with geology, these factors are all heterogeneous, uncertain, time varying and represented through sparse and incomplete datasets. Recent work (Valenta et al) is beginning to show us how these risks correlate in different global settings. By analysing data relating to known, but as yet undeveloped copper deposits, this work (the complex ore body database) is demonstrating that it is the combination of issues (both price sensitive and non price-sensitive) that determine the viability of a deposit for extraction in the 21st century.CITATION: Littleboy, A, Plint, N and Valenta, R, 2018. Mining as a complex system: do we need a new model?, in Proceedings Complex Orebodies Conference 2018, pp 41–43 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By J G. Webster-Brown, K L. Brown

The Waihi Region is host to many low sulphidation epithermal Au-Ag deposits. The Golden Cross mine located at the head of the Waitekauri River, eight kilometres NW of Waihi, was a gold mining operation that placed significant emphasis on environmental management. An assessment of the influence of this mining project on stream sediment geochemistry (Fe, Mn, As, Cu, Pb, Zn, Cr, Cd, Ni, Ag and Se) in the Waitekauri Catchment has been made. Effective waste management during the mine operation appears to have prevented contamination of stream sediment. Trace metal concentrations in the Waitekauri Catchment sediment have generally decreased since 1987, and are currently mainly below the ANZECC (2000) sediment quality guidelines. However, elevated As levels were recorded in the Upper Waitekauri River and Battery Stream, exceeding guideline values. Elevated levels of Cu, Pb, Zn and Cd were found in the Huanui Stream, a tributary of the lower Waitekauri River. This reflects the influence of past mining operations in the valley, as well as natural weathering of hydrothermally altered Coromandel Group andesite. At a number of sites, Mn concentrations also exceeded sediment quality guidelines, and this may be derived from the remediated Golden Cross mine site.

Jan 1, 2003

The Australian metallurgical processing industry has shown great innovation and progressiveness over the past ten years. During the same period, exploration activity, particularly by Australian companies, has increased substantially in Indonesia. Following feasibility studies, the decision was made to establish a metallurgical laboratory and design facility in Indonesia. An Indonesian partner was selected, and legal and corporate matters were determined. The laboratory was established but proved far more difficult than a similar undertaking in Australia. Australian and Indonesian staff were recruited and training programs, including training of Indonesian staff in Australia, were implemented. Difficulties of operating in Indonesia included: ò language difficulties ò _ local pace of life ò culture ò communications. Rewards of the decision to establish the means to present the technology to Indonesia have included: ò a contribution to Australia's export of technology. ò an opportunity to expand Normet's client base. ò the opportunity to learn aspects of a foreign culture. ò the means to establish a sound long term investment. This export of technology from the Australian mining industry to Indonesia is an example of the initiatives and capabilities shown by the Australian mining service industry.

Jan 1, 1989

By Murdaugh W

The application of photogeological techniques and analysis of more advanced remote sensor images can be a cost and time effective tool in the search for desert placer gold deposits. Examples are given of regional analysis using standard false color composit Landsat images and conventional black and white aerial photography. The examples include identification of sites to sample to evaluate the pathways of .alluvial gold migration and identification of potential sites of concentration. The results of these studies developed an increased number of target areas and exploration in proceeding with promising results. In addition to the development of additional target concepts and identification of specific target areas data useful to evaluation of mineability can also be obtained from photogeological investigation. Some indication at least can be obtained of the existence of duricrusts and salines that may hamper mining. Identification of possible sources of water is another important task in the desert environment. In addition indications of the clay content of the material to be worked is very important because of its economic impact on operational costs and overall recovery. The application of photogeology to these questions is discussed.

Jan 1, 1988

By Johnson N. W

After an unsuccessful transfer from the laboratory to the pilot plant of galena flotation technology which used sodium metabisulphite and ethyl xanthate, laboratory flotation tests were conducted to identify any unusual variables which had a deleterious effect on the position of the lead rougher grade recovery curve for Hilton and Mount Isa silver-lead-zinc ores. Two variables (pulp temperature and contact time for ethyl xanthate and sodium metabisulphite) had important deleterious effects.The findings allowed a successful transfer of the laboratory process to a pilot plant scale process. The effect of temperature was important because the higher temperature (40°C) in the pilot plant pulp increased significantly the rate of reaction between ethyl xanthate and sodium metabisulphite. In the laboratory process at 20 to 25°C, the reaction rate was lower and did not interfere significantly with the process. The contact time for the two reagents was also important in the pilot plant scale process because of the higher reaction rate at 40°C.To employ ethyl xanthate in the pilot plant process, special precautions were required. Further, a collector (Aerofloat 241) from the dithiophosphate family was used successfully in the pilot plant process.

Jan 1, 1988

With a price slowly rising above US$35 per ounce gold became a mineral worthy of prospecting and mining endeavour in the early to mid 1970s. Fortune therefore appeared to smile onNew Zealand with its favourable geological environment for gold and past record of major gold production from both hard rock and placer deposits. This was a particularly welcome development as the post war years, including both the base metal exploration boom of 1967/1971 (which produced major nickel, iron and bauxite mines in Australia) and the earlier period of uranium exploration failed to produce any mines in New Zealand with the exception of the small Tui Mine and iron sand mining. Whilst hard rock mining now appears imminent it is 15 years further along the track since the 1967/1971 exploration boom and eight years since the upsurge in prospecting for gold in 1978. New Zealand still has no hard rock base or precious metal mining. This is not for want of proven or potential gold mining situations for these clearly exist at Waihi, Monowai Reef, Golden Cross, MacRaes Flat and elsewhere.

Jan 1, 1986

By Madgwick J. C

Leaching column techniques and microbiological methods have been described in detail in Madgwick and Ralph (1980) and Madgwick, Ralph and Sadler (1981).Sixty-nine kilograms of copper porphyry ore (0.4 per cent Cu, 2.7 per cent Fe) (particle size 2.4-11.2 mm; 60 The effect of sodium chloride (O.6M) irrigation on bacterial leaching of Bougainville copper porphyry ore was studied.Viability of suspended Thiobacillus ferrooxidants was reduced to less than 10 cells/ml in NaCI (O.6M) compared with 10' eells/ml in dilute II,SO, (0.01 M, pll 2). Salt irrigation had no significant effect on heterotrophic and sulphur oxidizing bacteria. Increascd short term recovery of copper (145 g/tonne/ 15 days) was followed by a marked decrease in tenors to less than 20 mg/litre/day compared with an acid leach, steady release, of 110 mg/litre/day. Resumption of acid leaching restored average solution copper to 46 mg/litre/day and the viability of suspended T Ierrooxidates to 10 cells/ml.Quantitative removal of sodium ehloride from ore particles was difficult and t races of NaCI remained for more than 200 days.

Jan 1, 1982

A rotating disc geometry was used to provide a uniformly accessible surface for a kinetic study of copper cementation with zinc in sulphate solution. For copper concentrations of the order of 10 p.p.m., a porous, adherent deposit is formed on the zinc surface and this has a significant influence on the reaction rate. When the specific mass of deposit is less than about O· 35 mg/cm2 the surface may be considered as smooth and the rate is described by simple convective counter diffusion of zinc and copper ions through a laminar diffusion boundary layer to the deposit-solution interface. In the presence of additional deposit, the diffusional mass transfer rate is increased by increased surface roughness.The rate under these conditions is first order, with the degree of enhancement independent of further increases in the specific deposit mass. The enhancement in rateis, however, directly related to the initial mass flux and the species involved in the reaction.Preliminary work showed the same mechanism to apply to cementation from chloride solution, solutions of high zinc concentration, and cementation of copper with iron..

Jan 1, 1970

IN the underground department of a mine, we may fairly say that "good management is based upon three elementals: first, sound engineering; second, proper coordination and efficiency of every human unit; third, economy in the purchase and consumption: of supplies.This paper is practically an analysis of the second element; which stands out prominently as the most important in the winning of successful results. The human units are divided into officers and men. The officers intermesh. One man takes responsibility where another throws it down; incessantly new conditions are arising where they may be doubtful of their powers; and always, on account of the three shifts, varying methods of work are coming into conflict. This very often results in disorganization. What is most necessary to guard against this is an esprit de corps, which would influence officers to stifle personal feelings for the general welfare of the department, To secure co-operation and loyalty of the staff, the writer recommends for the mines of the field a system of profit-sharing. Distributed on a salary basis, together with liberal holidays (not less than three weeks in each year) on full pay...

Jan 1, 1912

By C Quirion

Agnico-Eagle Mines Limited, Laronde Division, operates the deepest single-lift shaft in the western hemisphere. The initial Penna hoisting plant was designed for a production rate of 1800 tonnes per day (t/d) from a 2240 m deep shaft. Exploration success, while sinking the shaft, led to a decision in 1998 to increase the production rate to 4500 t/d of ore from a loading depth of 2200 m. The new production rate was achieved by increasing the size of the rope and reducing the rope static factor from the existing 5.0 required by regulation to a static factor using the formula 25 000/(4000 + L) contained in a draft document that would eventually become SABS 0294 in South Africa. The formula permits Laronde to use a static factor as low as 4.0. The upgraded Penna hoisting system is the first hoisting plant outside of South Africa to meet the South African requirements. This paper describes the conversion of the hoisting plant to the lower rope selection factor in the year 2000 and the operating and maintenance issues experienced since then.

Jan 1, 2005

In the current climate, there is a real need to bridge the gap between theory and the real world mining considerations, and develop viable, cost-effective, high performance thickeners. With a greater need to extract profits from both difficult-to-process ores and lower grade orebodies, coupled with the necessity to produce 'greener', less water intensive technologies, suppliers need to take current thickener designs to the next level and into the 21st century. The complexity of 'getting it right' within a thickenerÆs feedwell, the 'nerve centre' of the thickener, is no small task. Delivering dilution water and mixing this water with incoming feed slurry, addition of flocculant, maximising flocculant-slurry interaction to build aggregate size, minimising unabsorbed flocculant percentage, volume average of solids volume fraction, momentum dissipation ratio, dilution recycle ratio, volume average shear, maximum shear rate at exit, aggregate size on exit, uniform discharge profile and more ù all of these need to occur in the right order and in the right proportions within the feedwell. This paper discusses the genesis and evolution of a new feedwell design, the first major innovation in the thickening industry in over 15 years.

Jan 1, 2008

By M Kuruppu

Large mining operations require a high percentage of the capital invested in mobile and fixed mining machinery. From an investment point of view this expenditure must be met by an equally high rate of return, thus the need for high plant and equipment reliability is of major importance. Equipment downtime is undesirable and very costly, resulting in lost production and revenue, which is of critical importance to successful mining operations. One of the solutions to this problem may be found in the form of competent computerised maintenance management software systems, which help to reduce the problem of breakdowns. These software assist the engineers for the management of service orders, resource allocation, progress monitoring as well as costing. They also facilitate the communication of targets and objectives among the service personnel. A computerised maintenance management software called MAINPAC was used to record and plan the activities of mobile equipment maintenance in a large mining operation in Western Australia. Among the details recorded were equipment data, service history, machine downtimes, previous maintenance, job planning and the resource required. This information further helped to analyse the maintenance efficiency, availability and the reliability of the equipment.

Jan 1, 2006

The correct assessment and understanding of geotechnical conditions is fundamental to mine design and, hence, successful (safe and efficient) mine planning, design and operations. However, this assessment and understanding is simply not possible unless there is a sound appreciation of the geology of the project. This paper addresses geological uncertainty in mine engineering and its communication, and shows that a mining project that does not take geology properly into account in the engineering phase is fraught. Uncertainty levels become excessive, which leads to hazards and consequential risks in design and operations in terms of both safety and efficiency. Several examples, both positive and negative, are provided to make the point. The paper concludes that mining geologists must become more overtly cognisant of the influence of geology on mine engineering. Equally importantly, mining (and geotechnical) engineers must communicate better with their geological colleagues to ensure that they (the engineers) have a clear understating of the geological issues affecting their operations. The engineers must know how to ask the right questions of the geologists. Engineers who do not understand and take account of geology in their designs and operations are failing the expectations of stakeholders.

Jan 1, 2006

As an older member of The AusIMM, I received my 30 year æPearl AwardÆ in June and had my 50th birthday two weeks ago, I am honoured to be here today. I thank those responsible for their confidence in me and in my ability to hopefully hold captive a broad group of individuals who are here as equals, sharing an interest, no a passion in blasting technology and associated works à over the two days you will hear some excellent operational and technical presentations I am sure. But today I will digress; I want to talk about the importance of leadership and how it indeed can be the catalyst for success, improvement and change. There has been much written about leadership, its principals, the charismatic leaders, the doÆs and donÆts and so on à and I for one am not about to give you the Holy Grail; there are many experts with greater wisdom than I on this subject matter. What I do want to do is explore the application of this passion to examples within the world stage and some examples drawn from my experience in mining.

Jan 1, 2007

In simple terms, heap leaching means the removal in solution of valuable elements from a heap of material, and their recovery from that solution. The heap of material can consist of essentially unprocessed ore, sub-ore, low grade gangue and country rock, tailings from other upgrading processes, or artificial materials such as slags or furnace and flue products. The solvents can be solutions of acids (commonly sulphuric acid because of cost) or of other chemicals such as cyanides. Because of cost factors the solutions are aqueous; because of this, leaching operations may be curtailed in cold-climate areas. The guiding principle must surely be `large volume / low cost'. Since solutions are generally easier to manage than gases, there is a strong incentive for replacing roasting of materials by leaching, eg arsenical gold ores. Where sulphides are present in the material to be leached, these may provide the necessary acid, with or without the aid of bacteria, to dissolve and extract the recoverable metals. The mineralogical aspects of the operation relate to the nature of the `ore' and gangue minerals present in the heap, their textural relationships, and their effect on the process itself.

Jan 1, 1994

Risk management for resources and reserves includes examining the fundamental processes of data collection, interpretation, modelling and estimation. Newmont Australia has developed a procedures manual to assist mine sites to build Resource block models, estimate Ore Reserves, validate the outcome and report the results. An audit scheme has been developed to compliment the procedures manual by assessing the degree of site compliance with recommended practice. A score of between one and five stars is awarded to each site depending on its performance in the audit. Audits are undertaken by a team of three Newmont personnel over a three to five day period at each site. Scores are ultimately compared between sites and reviewed annually. The objective of the program is to encourage continuous improvement in the modelling, estimation, validation and reporting practices used at sites and in advanced projects. The scheme provides a method of risk management for the companyÆs biggest asset û its Ore Reserves. Newmont Mining Corporation is preparing to use the audit scheme internationally in part to conform with recent legislation requiring US companies to demonstrate that management systems and procedures are in place to monitor and verify the companyÆs assets.

Jan 1, 2003

The three papers reviewed here consider different problems of mine management. Comparison of two of the papers demonstrates a marked contrast between the old and the new, in terms of mine management and impacts. The third paper discusses post-mining rehabilitation. The paper "The impact of a derelict base metal mine on the aquatic environment", by Brooks and Mclveen contrasts strongly with the paper "Narbarlek Uranium Mine design, construction, operation monitoring and decommissioning of the water management system" by McLoughlin, Grounds and Weatherhead. Brooks and Mclveen detail the contamination emanating today from the Conrad Mine in New South Wales which was mainly operated for 15 years at the turn of the century and later for 7 years in the 1950's. The mine was apparently developed over the years on an intermittent, ad hoc basis with no regard to contamination management, resulting Ti significant contamination persisting through time. This type of mining development is the antithesis to the type of planned mining and management operation which was carried out in Arnhem Land at Narbalek, and which apparently resulted in no uncontrolled contaminant release and successful decommissioning of the mine.

Jan 1, 1988