Search Documents

By Knijnikov M, Cameron D

Coal Quality management and the control of the flow of coal through complex mining preparation and transport phases of standard mining operations has assumed greater importance over recent years.

Jan 1, 1998

The Late Permian intermediate to silicic talc-alkaline Drake Volcanics of New England, N.S.W., consist largely of shallow marine, redeposited volcaniclastic rocks which host epithermal Ag-Au deposits. Pervasive hydro- thermal alteration is widespread. The 200-300 m Cataract River Member includes several sedimen- tation cycles composed of massive pumice brec- cias, overlain by laminated sandstones and siltstones, interbedded with marine, fossil- iferous mudstones. Two distinct groups of cla- sts exist within the volcaniclastic beds: 1. Lithics of predominantly intermediate compos- ition lavas that have undergone subaerial epi- clastic erosion and transportation; 2.Pumice, quartz and plagioclase crystals which have not been reworked by epiclastic processes. The lithic clasts were derived locally in a sub- aerial environment within the Drake Volcanics, and pumice and crystal fragments from contem- poraneous centres of silicic volcanism else- where in New England, N.S.W. The latter group of clasts was transported to Drake by Plinian airfall or rafting, and fell and was washed on- to emergent portions of the Drake Volcanics, where reworked locally derived fragments occ- urred. Cold state subaqueous mass-flows, prod- uced by slumping, resedimented the mixed vol- caniclastic detritus into the marine basin in a series of cyclic units with massive lower parts, and laminated upper zones. Modern ana- logs of the palaeogeographic setting in New England, N.S.W., in the Late Permian are pro- vided by the Taupo Zone, New Zealand, and sou- thern Kyushu, Japan.

Jan 1, 1987

By Corbett GJ, Leach TM

The Nena Cu-Au high sulphidation deposit has formed within the Frieda River Intrusive Complex in association with a major dilatant structure. Multiple intermediate intrusives of Miocene age are localised by a splay (Frieda Fault) of the Fiak-Leonard-Schultz Thrust, a several hundred kilometre long structure, formed parallel to the accretionary prism of northern Papua New Guinea.The high sulphidation systems including Nena, crop out as narrow silica-alunite ridges extending for up to 5-6km in length within a dilational structural environment. Alteration at Mena exhibits two phases of hydro-thermal activity: an initial stage, inferred to be volatile-rich, which has produced zoned alteration; and a later phase, postulated to have been a liquid-dominated fluid, which has brecciated earlier alteration zones and deposited gangue phases as well as Cu/Au-bearinq sulphides in open spaces.

Jan 1, 1994

This paper briefly reviews the background of mobile primary crushers and their current main areas of application. The benefits of applying mobile primary crushing and belt conveying systems are analysed. The impacts of applying such systems to different steps of the mine process are discussed, including mine development and planning. Application examples are used for demonstrating further possibilities to apply mobile primary crushing and belt conveying systems in mining projects successfully.

Jan 1, 2007

By Guerney P. J

A suspension of finely powdered ferrosilicon in water is the dense medium used in the gravity upgrading of iron ore, diamonds and other minerals. Ferrosilicon can he lost in the plant through corrosion. The greatest corrosion losses occur when

Jan 1, 1997

City Resources Limited selected Vanuatu as a target area for epithermal gold mineralization because of its relatively unexplored character and its location on the southwest Pacific rim. During 1985 a systematic program of reconnaissance prospecting was completed on six islands within the Vanuatu group, using a helicopter and a specially designed exploration support vessel with on-board assay laboratory. Within a period of 4 months, reconnaissance prospecting of all six islands was completed, two previously unknown epithermal gold provinces had been discovered, and six major prospects warranting detailed exploration had been identified. Factors which contributed to the success of the program include (i) a flexible management approach, (ii) the mobility and access provided by the support vessel/helicopter combination, (iii) rapid assay turn-around, and (iv) adherence to basic prospecting techniques. The relative merits of various sampling media are discussed.

Jan 1, 1987

By LaBrooy SR

A number of gold processing plants in Western Australia have nickel in their ores, leading to significant levels of nickel on their loaded carbon. The presence of nickel during leaching, adsorption and elution'may have detrimental effects on cyanide consumption, carbon inventory requirements, stripping costs, electrowinning efficiencies and may contaminate the gold bullion.This paper discusses the competitive adsorption of gold and nickel cyanides onto activated carbon and investigates changes in solution parameters that may improve gold adsorption and/or inhibit nickel adsorotion.

Jan 1, 1997

By Hempenstall J, English W

Mine management has a responsibility under the various acts of state parliaments for the adequate ventilation of existing workings. It also has a need to plan adequately for the ventilation of proposed workings. Future workings alternatives have become progressively more complex and ventilation planning of the various possibilities must be undertaken within an atmosphere of rapidly changing market circumstances, etc. Any non-optimal solution will prove more expensive than necessary on both capital and cost bases. Clearly these increasing and alternative ventilation demands of coal mines in Australia have multiplied the work load of ventilation engineers. Management in general has for some time been aware of the advantages of using computers for commercial applications such as payroll and stores inventory. However, while the hand held calculator has replaced the traditional log tables and slide rules for smaller engineering calculations, the larger digital computer has not made the same

Jan 1, 1983

The Wattle Dam gold mine, located near Kambalda in the Goldfi elds region of Western Australia has recently progressed to an underground operation and is now believed to be Australia's highest grade operating gold mine. At end of March 2010, the deposit had reserves of 132 000 t @ 20.8 g/t for 88 000 oz and by the end of June 2010 had produced 110 000 oz from open-pit and underground mining. The Wattle Dam main lode is characterised by very coarse gold mineralisation. Gold occurs as cm to decimetre fracture fi ll veinlets, shear surface coatings and erratic fl akey clusters. The gold has no quartz or silica association and lacks adjacent low-grade mineralisation or alteration assemblage. Geologically it appears atypical of Archaean lode gold deposits and may represent an extreme end member of the type. Definition of the lode is largely dependent on effective geological identification of the host lode zone and an understanding of the erratic distribution and grade behaviour of a high-nugget, coarse gold deposit. Dependence on assay data to defi ne the lode zone would result in the deposit being mined incorrectly and much of the deposit being left unexploited. This paper discusses the geology, coarse gold characteristics and defi nition methods which are used to successfully defi ne and mine the deposit.

Aug 1, 2010

During the past three years Lurgi's Circulating Fluid Bed (CFB) technology has been successfully applied to roasting of refractory gold ores and con- centrates. In comparison with the so-called Stationary Fluid Bed roasting systems, a considerable improvement of gold recovery, to around 95 per cent, has been demonstrated and achieved on many occasions in pilot CFB units and in commercial CFB roasting plants as well. The major reason for such improved gold recoveries is the excellent controllability of the roasting process in the CFB reactor system. Here, temperature, gas atmosphere and solids residence time are more precisely controllable at optimal values during roasting operation in order to achieve the highest possible gold recovery in the subsequent leaching process step. Further dominant benefits of CFB roasting systems are their flexibility with regard to feed material, throughput capacity, dry or slurry feed, almost unlimited oxygen enrichment, direct fuel addition and in situ capture of SO2 in the presence of limestone and dolomite. The system will accept 50 per cent turndown ratio, large variations in feed composition and particle size, as well as a variety of different fuel types. The commercial applications of CFB roasting systems for gold con- centrates have been realized so far at Fimiston, Kalgoorlie/Westem Australia and for whole ores at Cortez, Nevada/USA.

Jan 1, 1991

As mining and extraction processes improve and lower grade ores become economic, mining for most ores have extended to depths beneath the zone of weathering oxidation created over geological history. These deeper openings expose sulphidic formations and reduced mineral species as either primary ore or simply as accessory or gangue minerals in the country rock. This is not new, underground mining for primary base metal and gold have long been familiar with these problems, as have coal and uranium miners. The change is simply that the number of mines exposing sulphidic waste rocks, tailings to the atmosphere and/or leaving behind dewatered sulphidic rock surrounding the mine void has increased the number of sites from where acid mine drainage (AMD) may emanate with consequential problems for the hydrological environment including downstream catchments (Miller et al, 1996). The principles of ecologically sustainable development (Brundtland, 1987) have been more or less ratified by all the developed nations of the world and this has led, amongst other things, to an expansion unprecedented in the research and documentation of means for achieving long-term environmentally acceptable stabilisation of solid wastes of all sorts. These have revealed that AMD problems can be minimised and even reversed in many cases by the integration or co-disposal of biodegradable organic wastes with oxidising sulphidic wastes (Elliott et al, 1996). This paper considers how this might be achieved at mine sites in Australia and the results encountered at some relevant sites.

Jan 1, 1997

By Morland R

In the course of an exploration program aimed at increasing Pasminco Mining's ore reserves, an electromagnetic survey down one of the underground drillholes at the North Mine, Broken Hill, recorded a broad and persistent response. This paper demonstrates that the anomaly was not due to any geological feature, but rather was caused by 'self-response' of the sensing probe. The observed results are due to the surveyed hole lying within a resistive environment and having distinct, but not unusual, changes in dip.This phenomenon has not been widely reported and we believe that there are likely to be similar cases in company records where very genuine looking responses are due to self-response rather than sulphides. These false anomalies can be recognised by correlating the observed data with the calculated down-hole component of the transmitting loop's primary field.

Jan 1, 1994

By Manlapig E. V

ABSTRACT- I Results are given for a series of tests in which a 300 mm pilot-scale Jameson cell has been used in copper recleaner flotation, and for the flotation of a lead rougher feed. the results indicate that the production rate of solids, at the same superficial air velocity Jg, is higher than in conventional columns. Thus in the copper recleaner application, the pulling rate reached 14 gm/cm2/min compared with between two and three for an operating column, while in the lead cleaner application the comparable figures were 12 - 14 gm/cm2/min for the Jameson cell vs 8 - 9 gm/cm2/min for a test column. A froth crowder was used to increase the air superficial velocity Jg in the Jameson cell in the copper recleaner, while holding the collection mechanism and pulp feed rates constant. The recovery increased from 50 per cent to over 90 per cent, suggesting that recovery is controlled mainly by the froth conditions, rather than the particle-bubble interactions in the Downcomer.

Jan 1, 1991

The Ramu chromite deposit occurs in the Marum Ophiolite complex and is the most economically attractive chrom-ite deposit in Papua New Guinea. Its lateritic nickel, chromite and cobalt potential has attracted several compan-ies to prospect the deposit.In the present work, the compositions of chromite in the Ramu lateritic deposit and coexisting olivine-chromite pairs in Marum Ophiolite dunite were analysed with the electron microprobe for Fe, Mg, Cr and Al. The results were used to determine the relationship between the cations in the tetrahedral and octahedral structures of the chromite. In addition, the Fe, Mg, Cr and Al cations of the coexisting olivine-chromite pairs were used to calculate the equilibrated temperatures of crystallisation of the chromite. The variation of Fe", Mg and Cr cation values of the chromite in relation to the calculated temperatures was studied by regression analysis.

Jan 1, 1994

The rocks of the Serranias Chilla massif of Bolivia are a suite of metamorphosed Palaeozoic basalts and associated continental sediments. Whole-rock trace element geochemistry of the basalts suggest a calc-alkaline affinity and indicate that subduction extended as far north as the Bolivian Altiplano during lower Palaeozoic time.

Jan 1, 1990

By T Ireland

The Project Hobson tunnel excavation was the first use in New Zealand of an earth pressure balance (EPB) tunnel boring machine (TBM). The tunnelling on the project was very successful and break-through was achieved three weeks ahead of program, demonstrating that tunnelling can be undertaken in Auckland with a high degree of cost certainty.Project Hobson involved the replacement of an existing 90 year old above ground sewer that crosses Hobson Bay in Auckland, New Zealand, and which had reached the end of its economic life, with a 3 km long, 3.7 m internal diameter segmentally lined bored tunnel. The NZD$ 118 M project has provided several environmental benefi ts to the Owner, Watercare Services Ltd and the local community:· provide capacity to meet projected growth in the region,· virtually eliminate wastewater overflows into Hobson Bay and the Waitemata Harbour, and· remove an obtrusive visual feature and open up the bay for recreational purposes.Auckland’s bedrock is a weak sandstone/siltstone (East Coast Bays Formation), subject to infilled paleovalleys. The geology in the region has been significantly influenced by volcanic activity; 49 volcanoes are present within 20 km of the city centre.The paper describes the design and construction challenges for the projects, including TBM performance, ‘sticky spoil’ management, and risks associated with basalt lava flows and two paleovalleys. The paper also highlights the reasons for the success of the project, including a rigorous approach to risk management during design, and effective planning during construction. Other useful data such as the effect on the watertable caused by closed face tunnelling, and ‘faceloss’ estimates derived from settlement arrays are included in the paper.Project Hobson also saw the successful implementation of a Geotechnical Baseline Report – one of the first uses of this type of document in Australasia.

Mar 8, 2011

By Diessel C. F K, Ng N

The commonly used Stopes-Heerlen coal petrographic classification and nomenclature has over the years been subject to variable interpretations. This paper discusses the problem with specific reference to the inertinite maceral group. The effect of various interpretations of the Stopes-Heerlen system on maceral analysis is discussed and illustrated by means of comparative analyses conducted by a number of laboratories in Australia. An attempt is made to define the reflectance thresholds used by the authors to subdivide the inertinite group; the genetic and technological significance of these thresholds are compared. The difficulties of distinguishing structured and non-structured macerals of the inertinite group is discussed in terms of possible improvements to the present Stopes-Heerlen system by extending the classification to include transitional maceral types.

Jan 1, 1969

By M McGrory, A Rodolfo, J Paredes, L E. Manguba, K A Villaspir, G Webb, R Setiagani, H Cardenas

"OceanaGold’s Didipio operation has been in operation for three years. Integral to the flow sheet design is a flash flotation circuit treating a portion of cyclone underflow, consisting of an Outotec SK-500 flash rougher and an Outotec TC10 flash cleaner and a SB-2500 falcon treating flash rougher concentrate to recover fine free gold.Flash copper recovery has been holding steady at 60 per cent, while flash gold recovery at 50 per cent. Gold recovery from the gravity circuit is 22 per cent, bringing the overall flash plus gravity gold recovery to 72 per cent.Operation of the flash rougher is mainly by pulp level control. Control of copper grade in the flash cleaner is mainly controlled by air inflow and flash cleaner pulp level control drives copper recovery. Gold recovery around the circuit is mainly driven by gold head grade.SB-2500 concentrate is scalped with a 250 micron screen with the coarse fraction reporting to a SB-250 falcon, concentrate of which combines with the screen fine fraction to a Gemini table.Citation:Cardenas, H, McGrory, M, Webb, G, Paredes, J, Setiagani, R, Villaspir, K A, Manguba, L E and Rodolfo, A, 2016. Didipio Flash Flotation and Gravity Recovery Circuit, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 123–126 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By A Remes, A Dennis, M Talikka, T Kotiranta, S Horn

A mine project combines vast amounts of information from various disciplines including but not limited to geology, mining, metallurgy, technology, environment and economics. In many cases, all relevant information is not fully shared between all disciplines. Thus, project performance (technical, economical and sustainability) may be evaluated on basis of insufficient information resulting in non-optimal decisions, project execution and risk management. Advances in computing power and simulation software enable various data sets to be incorporated in a single digital platform enabling more efficient and transparent data sharing. In addition, linked data sets and simulation can support assessment and optimization of the project as a whole rather than focusing on optimization of individual events. CITATION:Horn, S, Remes, A, Kotiranta, T, Talikka, M and Dennis, A, 2018. Evaluation of sustainability of copper production value chain from ore to metal using advanced simulation, in Proceedings Life-of-Mine 2018, pp 87–89 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By Finch W, Dunne R

Understanding how liberated and unliberated minerals behave in comminution and classification circuits is of vital importance to ensure that maximum liberation occurs without unnecessary and costly overgrinding. This paper presents the results of a study carried out by the Julius Kruttschnitt Mineral Research Centre and Newcrest Mining of the liberation performance of Newcrest Mining's New Celebration grinding circuit. Using data from surveys of the circuit, together with QEM*SEM analyses of individual streams, a detailed picture of the liberation and classification of gold-associated pyrite is presented. In addition the relationship between the QEM*SEM analyses and results from laboratory leach tests are also discussed. Using the survey and QEM*SEM data, mathematical models were constructed of the performance of the ball mill and cyclones, and simulations carried out to investigate ways of improving the performance of the circuit. The results from the more promising scenarios are Reviewed.

Jan 1, 1993