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By G Bignall, I Chambefort, A B. Christie, A J. Rae, M P. Simpson

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Key indicator hydrothermal alteration minerals formed from fluids of known fluid composition (neutral versus acid pH) and temperature have been mapped for New Zealand (NZ) geothermal fields by visible/near-infrared (VNIR) and short wave infrared (SWIR) reflectance spectroscopy. Smectite, interstratified illite-smectite and illite formed from neutral pH fluids have zoned distributions with higher temperature illite (>220ºC) in and around the upflow of chloride waters and low temperature smectite (<150ºC) on the margins (eg Ohaaki, NZ). In adularia-sericite epithermal deposits, Au-Ag veins are similarly surrounded by zoned clays, with mineralised veins enclosed by illite (eg Martha, NZ) or occurring at the illite/illite-smectite boundary (eg Favona, NZ). Reflectance spectroscopy is also highly effective in identifying minerals formed from acid fluids; both steam-heated acid-sulfate waters (eg kaolinite and alunite at Rotokawa, NZ), or magmatic-hydrothermal fluids (eg pyrophyllite and topaz at Ngatamariki, NZ). These same alteration minerals commonly show zoned distributions in high sulfidation epithermal deposits (eg Rodalquilar, Spain) and in lithocaps associated with porphyry deposits (eg Lepanto, Philippines). Thus reflectance spectroscopy permits the rapid identification of key alteration minerals that can be mapped at a high sample frequency and used as vectors towards mineralisation.CITATION:Simpson, M P, Bignall, G, Rae, A J, Christie, A B and Chambefort, I, 2015. Mapping hydrothermal minerals in New Zealand geothermal fields using reflectance spectroscopy (VNIR-SWIR) and application to mineral deposit exploration , in Proceedings PACRIM 2015 Congress, pp 243–248 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

The Pasminco mine at Rosebery in north western Tasmania is a medium sized underground base and precious metals mine. In April 1992 a major wedge failure of approximately 5000 t occurred in the backs of a main access drive to the 18 level H Lens orebody. This collapse prevented access to 190 000 t of ore which had been scheduled for production in July - August 1992. At the time of the collapse, the mine was in a transition period between mining small pillar remnants of several other orebodies and developing to the new deeper J Lens orebody.The development at this orebody was behind schedule and it was necessary to find a cost-effective and timely alternative to a 75 m bypass drive around the fall area.A Lysaght- Fletcher multiplate steel arch was available on-site from a deferred surface road project and it was decided to use this arch to regain access through the fall area. Due to the danger of continued minor falls, the entire 18 m long, 3.95 m high x 4.5 m wide tunnel had to be assembled in the 4.7 m wide x 5 m high accesss drive and pushed into the fall area as a single unit.

Jan 1, 1993

By T Goswami, M Edmondson

Henry Walker Eltin (HWE) are the mining contractors for Gloucester Coal at Stratford mine, which is in an environmentally sensitive area in the Avon Valley, NSW, Australia. Normal blasting at Stratford is done in a æstand upÆ or æbox cutÆ mode to suit the truck and shovel operations. Recently an opportunity of doing a throw blast became available when part of a ramp had to be blasted to accommodate changes to the pit design while not damaging the remainder of the ramp. The objective was to maximise throw into the void in order to minimise excavation costs by reducing the amount of overburden to be moved by the excavation fleet. It was necessary that the best result be achieved while staying within the vibration and airblast limits at a neighbouring property and nearby township. Both objectives were achieved through the application of OricaÆs knowledge of blast design, modelling and i-konTM electronic detonators. The i-kon system was used because of its known benefits in cast blasting and environmental control. The i-kon system provides the blaster with much greater accuracy, control and the flexibility to tailor blast designs. It has been found previously to enhance blast throw and provide cleaner high walls (Brent, 2002). The blast was a success, producing a muckpile with a high degree of looseness and consistent fragmentation, with an average throw to final spoil position of 37.5 per cent. This was achieved without any environmental exceedance. In addition, high speed filming showed that the coal edge had remained largely in place, indicating minimal coal loss. The results exceeded the expectations of HWE Stratford and the overall cost savings to HWE Stratford from this blast were recognised to be substantial. Further throw blasting opportunities at Stratford have been followed using the i-kon system to maximise benefits.

Jan 1, 2003

By Eupene GS

The valuation of exploration properties which contain no identified resources or reserves is the most subjective of all valuation tasks likely to be carried out by a geologist. The geoscience rating method proposed by Kilburn (1990) recognises this inherent subjectivity but also attempts to apply some discipline to the valuation process. Some other methods used for valuations of this type clearly lack discipline and are open to misuse and abuse. The Kilburn method essentially requires the practitioner to justify all aspects of the valuation process. The valuer must specify and, more importantly, quantify aspects which enhance or downgrade the intrinsic value of each property. The intrinsic value is called the ""base acquisition cost"" (BAC) and it represents the average cost to identify, apply for and retain a base unit of area of title. The BAC and base unit of area both vary with different types of exploration and mining title but remain constant for similar types of titles in the same mineral tenure regime. In the Kilburn Method the enhancement/ downgrading factors are determined by the geotechnical prospectivity (Kilburn Method) within the title. A modified version of the Kilburn Method presented here (""Modified Kilburn Method"") also focuses attention on other real variables besides the geotechnical attributes which influence valuations of this type, viz., competition for tenure and activity in the markets in which the exploration properties are being traded. The most active such market at present is the stock market. By utilising uniform BACs and base units of area (for similar titles) for all exploration properties (in practice in Australia this is only possible within a particular State or Territory), the method exposes the valuer's opinions of each of these variables to the scrutiny of the investor. The investor (or his professional adviser) is afforded the opportunity to directly compare valuations on different properties by different practitioners and can assess how the final valuation is weighted in respect of geotechnical prospectivity, competition for tenure, and stock/financial market sentiment. No other method currently employed in Australia to value mineral exploration properties affords the investor this `luxury', which some may argue is their right.

Jan 1, 1994

The AusIMM is concerned about the longer tem sustainability of the minerals sector in Australasia. Our contention is that the sustainability of the sector is at risk if we do not:   ò encourage more exploration in Australasia by removing impediments and         increasing incentives; ò fund our university and research centres appropriately to increase both our   prospectivity, and our processing efficiencies; and ò manage our human resources better.   This paper will focus on how we can better manage our human resources to assist in ensuring sustainability of the sector in Australasia .   From a production point of view:   Economic output = f (Land, Labour, Capital, Environment) where Land refers to all of the natural resources used in production. As well as land itself it includes water, forest, fisheries, oil, gas and mineral deposits. Labour refers to the skills and capabilities used by humans in the production process. Capital describes all of the manufactured aids used in the process of production1. The challenge for management is to ensure maximum efficiency and effectiveness of labour in the production process whilst maintaining sustainable development.   The 1992 Rio Summit defined sustainable development as maintaining and enhancing:   ò natural capital û defined as all natural resources, both environmental and   those of traditional economic value; ò manufactured capital û made by human kind, including produced goods,     infrastructure and built environment; ò human capital û defined as the health, well being, intellectual capabilities and   spiritual welfare of individuals; and ò social capital û defined as social relations and consultations within and   between societies, their norms and functionality2.   The minerals sector in Australasia has successfully focused on the technical aspects of each of these components of sustainable development with primary attention applied to natural capital and efficient utilisation of manufactured capital. The technical aspects of human capital and social have also been addressed through an emphasis on occupational health and safety and interaction with local communities however I suggest that, to date, insufficient emphasis has been placed on labour (human capital) to maximise economic output1.   It has become increasingly common practice to identify land as natural capital, labour as human capital and capital as physical capital. That is labour has been treated as a commodity rather than an opportunity to create a comparative advantage and this will be the greatest challenge for mine management to show leadership over the next decade of the 21st Century.   This paper will outline characteristics of the sector which are relevant to the management and utilisation of labour, outline the outcomes of recent AusIMM surveys, review the reasons for the current and future anticipated skills shortages, some innovative responses to the challenges and finally, suggestions on how mine management can show leadership.

Jan 1, 2006

Structure is the most important control on the location of hematite deposits in the Hamersley Province in the Pilbara region of Western Australia. Unravelling the structural history of mineralised areas, however, is complex because the Province underwent three orogenic events, and three regional extension events followed the main episodes of compression. Steeply E to ENE dipping normal faults immediately predated deposition of the Beasley Quartzite of the lower Wyloo Group after the Ophthalmian Orogeny. Steeply NE and SW-S dipping normal faults predated deposition of the McGrath formation of the middle Wyloo Group, following the Panhandle Orogeny. The resulting interpreted rift was subsequently reactivated and tilted during the Capricorn Orogeny. Late NE trending normal faults are confined to the eastern half of the Province. High-grade hematite deposits occur in rocks that range from intensely folded (Mt Whaleback, Giles Mini) to rocks with less, or only little deformation (Paraburdoo, Channar), suggesting that folding had at best limited influence on ore genesis. In contrast, extensional normal faults are always associated with high-grade hematite deposits, and in particular faults that link the underlying dolomites of the Wittenoom Formation with the overlying iron formation, thus providing a pathway for mineralising alkaline fluids.

Jan 1, 2005

By B Walker, A Robertson, C Wels, S Fortin

A background characterisation study was carried out in the Sangre de Cristo mountains, New Mexico, to: quantify naturally occurring contaminant loads from mineralised areas; define site-specific background concentrations; and to determine key factors controlling spatial and temporal variations in contaminant concentrations. The study included a comprehensive sampling and testing program (paste pH/EC, ABA, leach extraction tests) of soil/bedrock from mineralised areas (including erosional scars), and a ground water and surface water quality monitoring program in selected mineralised watersheds. Results demonstrate that high concentrations of contaminants occur naturally in ground and surface water draining the mineralised area of the Red River basin. The erosional scars were found to represent the major source of acid rock drainage (ARD) (~66 per cent) in this area due to: high rates of weathering and erosion, which continually exposes sulfide-bearing outcrops; and high rates of run-off as a result of high elevation and lack of vegetation. The scar material is generally very acidic (paste pH ranges from 8.5 to 1.5; average = 3.6) with highly elevated concentrations of sulfate and leachable metals. The composition and concentration of leachable metals vary significantly, not only between scars but also within a given scar. While all streams draining the various scar watersheds are highly acidic, each has a characteristic æfingerprintÆ of sulfate and metal concentrations. Most of the run-off from the scars infiltrates into alluvial debris flow aprons and reaches the Red River via groundwater flow.

Jan 1, 2003

By S Slusarczyk, Z Kozlowski

Vibration of surface caused by seismic quakes can make a risk to great mining costruction. We have to do with this risk in the Belchatow open cut mine where seismic quakes of various energy and range have occured since the end of 1970s. The seismic risk influence on the mine structure with the special attention to the slopes of an internal dump has been presented. Hydrogeological and geotechnical conditions of the lignite mining and internal dumping of overburden and ash from Belchatow power plant have been considered. Seismic activity in Belchatow open cut from 1979 to 2001 was described and the connection between mine working and seismicity of this area was investigated. The energy and approximate location of the quakes and seismological parameters of the strongest ones observed from 1995 to 2001 were presented. The mechanism of the quake focuses was determined by means of the primary-arriving wave method. Stability of the slopes was evaluated by means of the Fellenius method. It has been found that seismic events occured in Belchatow region may cause only local eboulements whereas there are not any safety risks to the stability of slopes of the internal dump in Belchatow open cut.

Jan 1, 2003

The process of hydraulic transport through pipelines, world-wide well known for the trans- port of fine-grain solids is also being used to a greater extent in mining for the handling of 1rimarily coarse-grain solid - water mixtures r the removal of, for instance Coal and waste mixtures after coal winning rising hydraulic monitors, lings for backfilling underground and :her tailings and flotation waste to A large-scale test unit was taken into service at the Bergbauforschung GmbH (Mining P',search Company) in Essen-Kray, GFR, to ¦urther improve this technology. The unit was :fanned and built by Krupp Industrie- and +hibau of Duisburg in cooperation with i r

Jan 1, 1980

By Roberts JD

The design and installation of a major on-line stores and purchasing system, with built-in maintenance reporting and plant register capabilities, needs more than just close attention to computer design details. When the system must be available almost 24 hours a day to a number of mine stores sites, and is used by a variety of mining staff including engineers and stores clerks, as well as by remote purchasing and office staff, then simplicity of use, availability, fast response times, and other human factors become vital. Critical aspects include easy to use screen design, involving a change from the traditional hierarchical menu system, and fallback and recovery to the last transaction. Business, people and systems objectives need to be established at the preliminary design stage, so that results can be measured and corrective action taken. The amount and type of user involvement and training, at all stages from initial design to systems tuning, has a major effect on people wanting to use the system. Active user participation in systems design, data definition and collection, and use of relevant training material is needed. Project management and design problems can arise in working with database oriented computer staff, and certain design features are found useful in ensuring a responsive, robust overall system.

Jan 1, 1983

The Dizon open pit mine of Benguet Corporation in western Central Luzon, Philippines has yielded some 182 000 t copper, and about 26 000 kg gold and 48 000 kg silver as by products since it started operation in November 1979. The 140 million tonne orebody is associated with a small quartz diorite porphyry stock emplaced in volcanic rocks on the basal slope of a stratovolcano complex as stockworks, fracture fillings and disseminated sulphide mineralization averaging 0.43% Cu, 0.93 g/t Au and 2.5 g/t Ag. Intense hydrothermal alteration accompanied the mineralization that developed fairly distinct mineral assemblages within and around the intrusive. Post-ore volcanic activity later gave birth to an upward-flaring diatreme which broke out south of and adjacent to the orebody and partially destroying it. Subsequent volcanic activity buried the mineralized area along with the rest of the stratovolcano's surrounding slopes under a thick deposit of pyroclastic and laharic debris. Erosion eventually removed the volcanic cappings over Dizon and also exposed the quartz diorite porphyry stock which might have resulted in the truncation of a sizeable section of the Dizon deposit. The chain of stratovolcanoes that comprise southeastern Zambales range hugging the southeastern edge of the Zambales ophiolite is part of a west-facing volcanic arc that extends for some 300 km along the western margin of central and southern Luzon whose development has been correlated to the subduction in the Manila Trench located off the west coast of Luzon. Prominent WNW-trending lineaments that cut across the ophiolite appear to be splays of the Philippine Fault whose intersection with the Mt. Pinatubo stratovolcano complex might have localized the emplacement of a number of intermediate stocks along with the gold-rich porphyry copper mineralizations associated with some of them.

Jan 1, 1987

Enhancement of Energy Efficiency in Fine Grinding of Copper Sulfide Minerals Using a Pilot-Scale Stirred Media Mill - IsaMill The mineral liberation size of run of mine ores has dramatically reduced over recent years. As a result, the demand for fine grinding which is the most energy-intensive form of grinding has markedly increased in the minerals industry. Furthermore, the fine grinding costs increase exponentially with decreasing product particle size. As a result of the increased energy requirement for fine grinding, it is desirable to optimise fine grinding processes such as stirred media milling (ie IsaMill) to enhance energy efficiency, throughput and the product fineness. In the present study, the influence of slurry rheology, grinding media type and grinding media-to-feed size ratio on energy efficiency in a pilot-scale IsaMill was investigated under certain industrially relevant pulp processing conditions. It was shown that a critical rheological state existed, below which the energy required to achieve an 80 per cent passing (ie P80) 20 ¦m product size was unaffected by shear rheology (ie apparent viscosity and shear yield stress) whilst above which the grinding energy required increased dramatically with increasing shear rheology. Colorado River sand (3.35 mm) showed higher energy efficiency than MT1 ceramic media (2.5 mm) for a target P80 of 20 ¦m in the solids concentration range of 38 to 55 per cent by weight, but the former experienced more than four times the wear rate of the later. The high wear rate of the Colorado River sand may be due to its much lower hardness. For feeds with an 80 per cent passing (ie F80) 70 to 110 ¦m, 2.0 or 2.5 mm MT1 media appeared to be more energy efficient than 3.5 mm MT1 media whilst a media-to-feed size ratio of 41 to 53 is applicable for ~50 ¦m (ie F80) feeds for efficient grinding.

Sep 13, 2010

The use of systematic review methods, derived from System Safety approaches used in the North American nuclear power industry, have become an accepted approach for seeking "approval" for new coal mining equipment and operational changes in NSW. Based on risk analysis, they provide a valuable and needed framework for the reduction of losses related to people, equipment and production.

Jan 1, 1991

By A Asadov, D Nair

This paper discusses the determination of the percentage of crystalline material in a natural silica deposit which would be considered harmful to health (<10 ¦m). A sample of the natural silica material was recovered and split into a number of subsamples. Samples were sieved using a conventional dry sieve to remove material >300 ¦m before testing. Particle size analyses of the fine fraction showed 75 per cent of the material was below 10 ¦m. Initially XRD and XPS were run on the samples to determine the minerals and composition of the sample. The XRD revealed strong quartz peaks and smaller tridymite peaks with a high amorphous background. The XPS indicated traces of iron, titanium and carbon with dominant silicon and oxygen peaks. The structure of the sample was investigated using the SEM. It was apparent that there were a number of larger quartz crystals (>30 ¦m) with a mix of amorphous and crystalline in the finer fraction. It was also observed that amorphous material was attached to the surface of the crystals. In order to determine the percentage of crystalline quartz a known amount of quartz was added to the sample incrementally. On each addition an XRD scan was performed and the area under the peaks recorded. Back analysis of these peaks with an assumed percentage of crystalline material in the original sample gave a crystalline content of 30 per cent. The quantity at the respirable fraction was estimated to be 18.7 per cent.

Jan 1, 2003

The introduction of cement into underground backfilling at The Zinc Corporation, Limited and New Broken Hill Consolidated Limited mines to improve mining efficiencies gave rise to several major problems, the magnitude of which had not been anticipated. These problems were 1. A loss of recovery in the milling circuit due to the presence of cement 2. The presence of cement-rich slime layers on the surface of the fills 3. The introduction of a safety hazard due to the slippery nature of the surface of cemented fills 4. The deposition of cemented slimes on the levels and in underground sumps and dams. The loss of revenue due to decreased metal recoveries considerably offset the gains from increased stoping efficiencies and the use of cement was substantially reduced while, (a) the Metallurgical. Department attempted to identify the chemical nature of the problem and overcome it, and (b) the Mining Department investigated methods of reducing cement contamination of the ore stream. As a part of this investigation the Mining Department added polymeric flocculants to the cemented fill pulp. Testwork was carried out in the following steps 1. The available Alfloc polymers were screened to determine which was the most effective and what was its optimum dosage rate. 2. This polymer was used in the laboratory to determine the reduction of surface slime, clarity of water, and effects on strength and percolation of fill. 3. Fills were placed underground to substan- tiate the laboratory work. /+. The polymer was then added to all cemented fills going underground to study its effect over a long term. The use of flocculants not only improved the distribution of cement in the body of the fill, but also the distribution of the fines fraction of the filling material, practically eliminated slippery surfaces and improved the clarity of the drainage water. Flocculant is now added to all cemented fills and restrictions on the use of cement are gradually being lifted.

Jan 1, 1973

By Anderson DR, Tassell G

A major environmental impact study carried out in the sand dunes of eastern Cape York used image analysis of remotely sensed data to both select sites for ground investigation and categorise the different ecological units present. The approach adopted was particularly suited to the type of environment in question and allowed a high degree of quantification, at a high level of confidence, at costs several orders of magnitude less than conventional Methods.

Jan 1, 1987

Almost from the beginning of civilisation the inhabitants hadlearned the art of recovering and working copper to produceitems which were of use to society.From the early beginnings of the use of copper which can betraced back 6000 years and more, there has been an evolutionaryprocess accentuated in more recent times in which the art ofproducing alloys particularly with tin and latterly zinc and otherelements, has given society a wide range of useful alloys for usein industrial, domestic and architectural applications.

Jan 1, 1995

Determination of Flotation Kinetics of Coal Grain Types in a Pilot Scale Jameson Cell using Coal Grain Analysis Method

Sep 13, 2010

A field trial of the prompt neutron-gamma SIROLOG technique was undertaken by the CSIRO - Division of Geomechanics at Callide Coalfields during July 1989. The trial investigated whether the sonde could reliably be used for the determination of Ash and Iron Oxide (Fe2O3) in coal seams, which had a highly variable iron content. Ten boreholes were logged, being water filled of a nominal diameter of 120 mm. The logging probe employed a 1.6 ¦g 252Cf neutron source and a 51 x 51 mm BGO detector. The source to detector distance was 15 cm. The results from one exploration borehole at the Dunn Creek Mine are discussed in the paper. The rms deviations for ash and iron determination between the neutron-capture predictions of the geophysical logs and the laboratory - chemical assays were 1.9 per cent Ash and 0.88 per cent Fe respectively. Using existing empirical equations which relate iron oxide concentration in coal ash to Initial Deformation Temperature (reducing conditions) at Callide, it may be possible to indirectly determine ash fusion properties as least as accurately, on a more detailed ply-by-ply basis, and more cost competitively than current laboratory techniques allow.

Jan 1, 1991

By S C. Dominy

The grade of ore at Marvel Loch mine is directly related to the presence or absence of shear zones and quartz-sulfide-rich hornblende (¦ diopside) veining within areas of plagioclase alteration. An experienced geologist can identify these features in hand specimen. Practical rules have been developed to assist this visual identification. The structural sites and styles of alteration and veining most conducive to gold mineralisation have also been determined. The work has enabled a better understanding of the geological controls on mineralisation at Marvel Loch, and has clarified geological understanding for optimisation of grade control modeling, ore block mark-ups, and minimisation of ore loss and dilution during excavation. In addition to this, it has enabled a detailed understanding of mine scale structural controls, geometry and relative grade relationships.

Jan 1, 2003