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High-sulphidation (HS) gold, silver and/or copper deposits are generated in both the epithermal and the upper parts of the underlying porphyry environments over vertical intervals of up to 2 km. The HS deposits are generated in advanced argillic lithocaps, which are products of the absorption of acidic magmatic volatiles by voluminous groundwater systems. Mineralisation styles in HS systems reflect depth of formation as well as the interplay between structural, lithological and hydrothermal parameters. The deep parts of HS systems, at depths of >1000 m, are typified by disseminated copper¦gold mineralisation comprising digenite, chalcocite and covellite in pervasive advanced argillic as well as underlying sericitic alteration. In highly telescoped systems, such mineralisation may overprint porphyry stocks and associated quartz-veinlet stockworks. Intermediate levels of HS systems commonly contain fault-controlled copper-gold mineralisation, typically as enargite in bodies of vuggy residual quartz, silicification and/or massive pyritic sulphide. The shallow parts of HS systems, at depths of The exploration focus is on four principal HS mineralisation styles:copper (eg Chuquicamata, Monywa) or copper-gold (Wafi) in the deep porphyry-hosted parts of systems preferably, in the case of the latter, where supergene oxidation is limited and, hence, flotation may be used for metal recovery; copper¦gold-bearing replacement mantos and pipes hosted by carbonate wallrocks in the deep parts of systems (eg Bisbee); high-grade gold in late-stage veins or hydrothermal breccias that overprint the intermediate to shallow levels of systems (eg El Indio, Goldfield); and large, bulk-mineable gold deposits in the shallow parts of systems that were subjected to supergene oxidation, thereby permitting heap-leach treatment (eg Yanacocha, Pierina). To these preferred HS styles may be added the low-sulphidation vein or disseminated gold¦silver mineralisation that is commonplace alongside many HS systems (eg Victoria at Lepanto).

Jan 1, 1999

A New Technology of Applying SLon-2500 Magnetic Separator to Recover Iron Concentrate from Abandoned Tails

Sep 13, 2010

The Mineralogical Researches of Gold Ores and Technological Products at Operating Factory in Olympiada Mine (Russia)

Sep 13, 2010

By J Coward, S Bulatovic

There are currently two operators producing oil from the surface-mineable portions of AlbertaÆs oil sands (Syncrude Canada Ltd and Suncor Inc) and two other companies are proposing to enter the industry (Albian Sands Energy Inc in 2002 and True North Energy LP in 2004). Tailings from the two current oil sands plants contain approximately 220 000 tonnes per year of TiO2 and approximately 80 000 tonnes per year of zircon. This represents approximately six per cent of the worldÆs TiO2 consumption and approximately nine per cent of the worldÆs zircon production. With the commissioning of plants by Albian and True North, and the announced expansion of plants by Syncrude and Suncor, it is expected that these tonnages could quadruple in the next ten years. All of these operators have at least 50 years of reserves even at these expanded production rates. The occurrence of heavy minerals in AlbertaÆs oil sands has long been known and is well documented in the literature. There have been a number of attempts to produce market-grade products from this resource and the results of this work have been quite mixed. Typically, researchers have used the normal mineral dressing techniques of the industry and have found the mineral assemblage does not respond to these techniques all that well. This has led to the widely-held suspicion that there must be some difficult metallurgical problems associated with this resource. There are three main problem areas that have created difficulties for previous researchers:the bitumen coating on the sand grains; secondary mineralisation such as pyrite, siderite and calcite; and a high proportion of aluminosilicates (approximately 25 per cent) that have the same gravity, electrostatic and magnetic properties as other minerals in the heavy mineral suite. Recent work by Lakefield Research shows that these problems can be largely overcome with some novel approaches. The bitumen can be removed by washing with a solvent in the presence of a demulsifier; the pyrite can be removed by flotation; and the titanium and zircon minerals can be separated by selective flotation followed by conventional electrostatic and magnetic separation.

Jan 1, 2001

Sphalerites from Devonian cassiterite-sulphide deposits and Pb-Zn-Ag fissure veins have similar ranges of Cd contents, but the average Cd and Fe contents could indicate a small initial difference in availability of Cd between the Zeehan-Renison Bell district and the Mt. Bischoff-Waratah district. Sphalerites from banded Pb-Zn deposits (Rosebery and Hercules) are characterized by low Cd content which is a world-wide feature of such deposits in exIrusive rocks, and may indicaIe a genetic relationship between ore deposition and vulcanism.

Jan 1, 1968

By D Wiseman, D Weedon, T Akroyd

Models of the size specific processes of particle collision, attachment and detachment have been combined in a form suitable for analysis of a full-scale flotation plant. The model is based on a first principal approach to particle collection by bubbles. Parameters considered include particle size, bubble size, particle contact angle, energy dissipation, entrainment and froth recovery. Using data structures configured within an Excel spreadsheet using æLimn: The Flowsheet ProcessorÆ, the model has been incorporated into a description of the individual cells within a simple roughing and cleaning flotation circuit. Simulated feeds of varying particle size distribution, feed tonnage and varying mineral hydrophobicity representing different mineral phases are presented to the model to produce predicted final concentrate grades and recoveries. Practical techniques for measuring many of the parameters included in the model are now becoming readily available. However, relating the terms included for contact angle, energy dissipation, entrainment (ie water recovery) and froth recovery to measurable parameters in operating plants remain as continuing challenges for research.

Jan 1, 2004

Pilot-Plant Testing of Ammoniacal-Cyanidation for Gold Recovery from Copper Gold-Bearing Ore The results of pilot-plant tested ammoniacal-cyanidation of gold recovery from copper gold-bearing ore are presented in this paper. This ore is from a deposit of Russian Federation with gold and copper grade 9.5 g/t and 0.4 per cent, respectively. Copper is largely present as malachite and azurite. The presence of chalcopyrite and bornite is also observed. In order to recover gold, gravity is recommended. Two options of ammoniacal-cyanidation using leaching of gravity tails, CIP and filtration, were tested. It was found that ammoniacal-cyanidation using filtration of leaching tailings and recycled solutions is the most optimal option. The proposed flow sheet provides for 89.7 per cent gold recovery from gravity tailings at the consumption of NaCN 0.9 kg/t and (NH4)2CO3 7.5 - 9 kg/t. Compared to conventional cyanidation, this technology decreases the consumption of sodium cyanide from 4 up to 0.9 kg/t at the same gold recovery. It can be recommended for the treatment of copper gold-bearing ores with the similar composition.

Sep 13, 2010

The Effect of Molecular Weight on the Adsorption and Efficacy of Polysaccharide Depressants

Sep 13, 2010

By N Rivera, A Music, C Cisternas

In an underground mine operated with panel caving and subjected to high stresses, geotechnical events such as collapses or rock bursts are fairly recurrent. Both situations can involve risks for people, considerable production losses and increasing operational costs.This paper discusses an operational methodology for the recovery of the undercutting front carried out at El Teniente mine, which uses panel cave mining with post-undercutting, after the occurrence of severe damage due to a seismic cluster. The main objective of the recovery of the undercutting front is to prevent the spread of the collapse to the production level, risking the operational continuity. The methodology is the result of repairs that were carried out in the year 2014 at the North Reserves sector from El Teniente mine. Its characteristics are an undercutting front of almost 1000 m long, with the presence of relevant structures and faults, high stresses and high seismic activity.The practical implementation of the proposed methodology was successful since it prevented the spread of the damage, completely recovered the undercutting front and avoided production losses during the execution of the repairs. Also, considering the origin of the damage and the operations associated to the subsequent recovery of the undercutting front, in this paper we discuss the main control variables to be measured. These variables should allow any operator and short-term planner to take action in mines operated with conventional panel caving in a complex geotechnical environment.CITATION:Rivera, N, Music, A and Cisternas, C, 2016. Recovery of the undercutting front in a mine with conventional panel caving – case study at North Reserves sector, El Teniente Mine, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 713–722 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

Geophysical surveys are currently being carried out over mineral prospects all around the Pacific Rim. Many of these surveys are successful in locating mineralisation in porphyry intrusives, mesothermal environments, and epithermal vein systems. A number of examples of surveys in Indonesia and Papua New Guinea are presented, which show the successful application of various geophysical techniques to the discovery of mineral deposits on the Pacific Rim.

Jan 1, 1999

By D C. McPhail, S L. Rogers, J Brugger

Using iron- and sulfur-oxidising bacteria to catalyse the breakdown of sulfides that host the gold is an important biological method for the pretreatment of refractory gold ores. Following this biological treatment a combination of chemical and physical methods are used for leaching (such as the cyanide process) and concentration (such as carbon-in-pulp or electrowinning) of gold. Although these methods are well accepted by industry, they harbour limitations in the processing of low-grade refractory ores, and regulatory agency/public acceptance of cyanide use. Thus, it is beneficial to industry to develop environmentally friendly, cost-efficient leaching and concentration techniques that are based on micro-organisms. This may soon be possible by adapting the results of recent regolith geoscience research, which has shown that micro- organisms are capable of driving a biogeochemical cycle of gold dispersion, transport and reconcentration in the supergene environment. The indigenous microbiota in biologically active soil microcosms from a number of Australian sites are capable of solubilising up to 80 wt per cent of the gold contained in these materials during 50 days of incubation. Studies using molecular microbial techniques have shown that a metallophilic bacterium, Ralstonia metallidurans, is present in biofilms on gold grains from a number of Australian sites. R metallidurans is capable of actively accumulating gold from solution, suggesting that the bacterium may contribute to the formation of secondary gold grains and nuggets. Identifying the biochemical and physiological pathways that lead to the dispersion and accumulation of gold in regolith, and quantifying the reaction kinetics of these processes may thus lead to the development of industrial bio-processing capacities for gold-containing ores.

Jan 1, 2007

The Manto Verde mine is found in the coastal ranges of the Atacama desert, 1000 km north of Santiago, Chile . The deposit is a fault-breccia specularite-oxide copper mineralisation hosted by the Jurassic andesites of La Negra Formation. It is located in a tensional fault that joins twoparallel arms of the Atacama Fault. The mine is in feasibility study: reserves are of the order of 60 Mt at 0.9 wt per cent soluble copper; mining will be undertaken at a rate of 11 000 tpd utilising an open pit and the ore will be heap-leached with acidified sea water, with copper recovery and by SX/EW.

Jan 1, 1992

Effect of Spacer Chain Length on the Flotation of Kaolinite and Quartz by Using Gemini Surfactants as Collector

Sep 13, 2010

By A G. Cuison, B V. Andam

Three well-known copper and gold deposits in northern Luzon, Philippines are located in the Mankayan Mineral District. These are the Lepanto Copper-Gold Deposit, the Far Southeast Porphyry Copper Deposit and the newly discovered Victoria Gold Deposit. The latter discovery led LCMC to shift from a predominantly copper mine to a gold mine. The pre-Eocene Lepanto basement andesite and the middle Miocene Balili volcaniclastic sequence underlie the Mankayan Mineral District. They are intruded by tonalitic to gabbroic Bagon Intrusive followed by diorite-quartz diorite intrusions. Diatreme emplacement of late Miocene-early Pliocene Imbanguila dacite pyroclastics and porphyries took place much later. Faults in the district mostly form a conjugate fracture pattern dominated by north and northwest trending shears, east-west trending extensional fractures and few north-south trending fissures. Victoria is an epithermal gold-base metal rich quartz vein deposit. The veins occur along tensional structures and it is common to observe crustiform and banded features among the sulphides and gangue minerals. It is an open space infilling type of mineralisation. The Victoria vein systems are divided into zones based on continuity. In each zone are major veins and associated spits. Dacite pyroclastics and porphyries predominantly host the major veins with a few narrow veins hosted by the Balili volcaniclastics and the Lepanto metavolcanics. The veins generally trend east-northeast with 75 - 80 dips towards the south. The longest vein can be traced fairly continuously for a horizontal distance of about 600 metres. The vertical persistence of major veins exposed on three level drives has a range of 150 metres and can reach as much as 400 metres based on drill hole intercepts. The vein widths vary from two to eight metres. Right lateral movements of either the NW or NE shear faults could have produced the east trending tensional fractures. The development of ore shoot patterns was recognised and has been helpful to the mining operations. Cymoid loops with defined pinch and swell features are noted both laterally and vertically. Complementing the structural pattern is the distribution of gold values along veins where lateral and vertical continuity is also observed. Gold is associated with quartz, sphalerite, galena and chalcopyrite. In relatively high gold zones, the abundant sulphides are sphalerite and galena. In relatively high copper zones, there is an abundance of chalcopyrite and tetrahedrite. Galena is always associated with sphalerite but less in abundance. Chalcopyrite occurs either as separate bands from or associated with sphalerite-galena. Chalcopyrite and tetrahedrite appears contemporaneous with sphalerite and galena but in some portions the former cuts the latter sulphides. The predominant gangue minerals are quartz, carbonates and gypsum. Rhodochrosite is the predominant carbonate gangue. Few sulphides are found in the carbonates. Gypsum (anhydrite) is found cross-cutting early mineralisation. It carries very few sulphides. The alteration halos around veins are relatively narrow. In an outward sequence, the silicic alteration occurs very near the veins, followed by sericitic-argillic alteration then to propylitic zones. It is also common to observe veins bounded by propylitic alteration. Preliminary paragenetic studies show apparent three stages of mineralisation, the early-quartz (-gold) stage followed by a carbonate stage and a late-gypsum stage. The abundance of base metals relatively decreases towards the gypsum stage. The Victoria gold deposit could have some genetic associations with the Lepanto Cu-Au deposit and probably indirectly with the FSE porphyry system. It is relatively apparent that the Victoria quartz-gold-base metal veins could have occurred similarly as the quartz-gold roots overprinting the Lepanto enargite mineralisation. This overprinting signifies the waning stages of the entire hydrothermal system.

Jan 1, 1999

Distinguished guests ladies and Gentlemen. As many of you know, before I became a Labour Member of Parliament, I had an unusual career path for a politician, in that I spent quite a few years working in the business community. In other words, I was mainstreamed before I was institutionalised. Given that some of this time was spent working for the then Macraes Mining Company Limited, now Gold and Resource Developments NL, I feel that I may have a perspective on how things are seen, on both sides of the fence. In terms of public perception and esteem I am not sure which career option was the step up and which was the step down. So far what I have found very familiar, is that in both roles there is a gulf between the reality and the perception of that reality - a gulf that is both huge and hard to bridge. I think it is a point worth making here amongst another busy industry cluster, that we can all too easily get so embroiled in the day to day activities, that we lose sight of how this might look to those running on a different treadmill. I can still remember scratching my head at the beginning of some days, as I worked to get new mining projects started that I knew were going to bring real jobs and economic benefit to New Zealand, but ending the day feeling like I may instead have been proposing bringing back both strip mining and slavery. If I learnt one valuable lesson out of that time it was this: .... mining has become so publicly demonised on the road to ecological nirvana, that even attempting a lucid dialogue on mining issues, with some, is incredibly difficult.

Jan 1, 2000

The mining industry continues to be a major driver of the Australian economy generating over A$130 billion in export earnings in 2008/2009. However, the industry has been cited as a significant contributor to green house gas emissions. Australia's proposed carbon trading scheme, the Carbon Pollution Reduction Scheme (CPRS) will financially impact on mining operations; this calls for a holistic planning approach for mining operations taking into account the impact of the emissions trading scheme. Since carbon trading is a new area of study, particularly within Australia, the quantitative effect of the CPRS on the mining industry is uncertain and current mine planning practices do not directly consider emissions. This paper presents results of the study into the impact of the CPRS on a hypothetical large scale open pit operation, using a spreadsheet model based on linear programming and simulation. By varying the production rates, life of mine (LOM), carbon price and ore grades among other variables several scenarios were simulated to determine the impact of emissions trading scheme on the net present value of the project. This study found that the adoption of the proposed Carbon Pollution Reduction Scheme could impact mining operations in Australia by a three per cent to six per cent reduction in net present value, for carbon credit costs of $25/t to $50/t respectively. While the six per cent reduction in net present value for a mining operation is significant, rising fuel prices have had a similar effect in recent years. The most energy-intensive processes are the milling circuit and the flotation concentrator circuit. These processes are jointly responsible for up to 60 per cent of the total emissions, depending on the production rate and the level of offshore processing conducted. Clearly, the introduction of the CPRS makes it is imperative for mining companies to assess the impact of carbon emissions on a mining project during mine planning.

Dec 6, 2010

By T Christie, A Swain

Patterns of quartz veining in epithermal gold-silver deposits at Wharekirauponga, Neavesville and Ohui in the Hauraki Goldfield, have been analysed to determine the effects of different lithologies on vein distributions. At Wharekirauponga, quartz veins are hosted in rhyolite and minor andesite, with the andesite containing slightly higher gold grades. Local basement andesite, rhyolitic tuff and silicified black shale host gold-bearing quartz veins at Neavesville. At Ohui, quartz veins are hosted in rhyolite, rhyolitic tuff and andesite. Fractal analysis was used to quantitatively describe the distribution of veining. The fractal dimension (D) of veining in silicified tuff is 0.25, moderately silicified rhyolite has D = 0.23 - 0.26, clay-altered andesite has D = 0.3, strongly silicified rhyolite has D = 0.3 - 0.39, silicified andesite has D = 0.4, and silicified black shale has D = 0.43. The D values are related to the composition of the host rock, and appear to be controlled by its competency. Hydrothermal silicification results in increased competency and higher D values. Vein thickness frequency plots for different lithologies show that andesite at Ohui, and to a much lesser degree at Wharekirauponga, contains more thick veins than rhyolite and tuff. Gold grades show a strong to fair correlation with higher vein density in three drillholes at Wharekirauponga. The fractal dimension of veining is an important control on fluid flow and gold deposition within an active epithermal system. Vein systems with higher D have a greater density of veining which would have favoured increased fluid-rock interaction. Lower D vein systems have more clustered arrays. The increased fluid-rock interaction induced by a high D vein system, when combined with a reactive host rock, results in an environment which is highly favourable for gold deposition. This situation is seen in the andesite at Wharekirauponga.

Jan 1, 1994

Study on Separation Technology for Copper-Molybdenum Collective Concentrate

Sep 13, 2010

Detailed characteristics of gold from Pliocene auriferous quartz gravels from Waimumu (Southland) have been studied using a combination of optical microscopy, energy dispersive microprobe analysis and scanning electron microscopy techniques. The gold at Waimumu is classified as either: 1. detrital gold, or 2. irregular gold. A number of different morphologies a recognisable within each 'gold type'. Evidence is given for an predominently authigenic origin for some of the gold at Waimumu.

Jan 1, 1987

By T J. Sprott, Associates

A number of people have expressed concern, understandably, that if mining operations take place in the Coromandel, the flows of mineralised ground water which exist will be intercepted. This water in many cases contains toxic metals including mercury, arsenic and lead and it is thought that if this water is allowed to enter streams or the waters of the Hauraki Gulf, it could endanger natural marine life and possibly established fisheries. This paper seeks to explain in simple terms the geology and the process of deposition of the various mineral deposits in the ground, the chemistry of the reactions between these minerals and the rain water falling on the ground, the hydrology and behaviour of this mineralised groundwater as it moves through the ground until it eventually enters the sea.

Jan 1, 1981