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By Jankola W. A, Delong O. J

Historically, the silica content of zinc concentrates treated at Cominco's Trail Operations has been low. Silica in the roaster calcine seldom exceeded 1.5 per cent because of the low silica content of concentrate from Cominco's Pine Point mine. With the shutdown of Pine Point, alternate sources of concentrate were required and it was anticipated that calcines containing greater than two per cent silica (with excursions above three per cent) would have to be treated. Previous experience indicated that the existing leaching circuit could not tolerate such high levels. Therefore, a research program was undertaken to identify the key factors affecting silica precipitation; to compare different process alternatives; and to make recommendations for modifications to the existing plant. A project to modify and upgrade the leaching circuit has now been completed. Calcines with higher silica contents are successfully treated, but the upper limit of the circuit is unknown. The results of the research work will be discussed and the new leaching plant will be described. Recent operating results will also be presented.

Jan 1, 1993

Traditionally, the predominant drilling method in open pit mining has been large hole rotary drilling using cumbersome, inflexible equipment offering merely limited scope for improvements in pit design and overall costs. By contrast, the recent development of comparatively light high-pressure down-the-hole hammer crawlers has paved the way for new ideas and trends. High penetration rates coupled with superior mobility and fast set-ups contributing to substantial productivity gains have resulted in a renascence for this drilling method in open pits. The ability to cover a wide range of hole diameters and angles gives designers unique drill pattern possibilities especially when establishing steep and stable pit slopes. As pre-split holes, buffer holes and production holes all can be drilled by using the same equipment, there are, there are obvious advantages in production scheduling as well as in materials handling and service. This paper presents some case stories, which will demonstrate the benefits and improvements that the introduction of new drilling methods and equipment has brought to open pit mining operations.

Jan 1, 2003

By M Dixon, T OÆShannessy

Melbourne Water (MW) is responsible for a section of existing gravity trunk sewer servicing the Melbourne central business district, Docklands, Port Melbourne and other adjacent areas, known as the Melbourne Main Sewer (MMS). MW has determined that the 2.2 km long 110 year old sewer will not adequately service these areas into the future or provide the level of reliability needed. The Melbourne Main Sewer Replacement project (MMSR) involves the replacement of the MMS with a new gravity sewer main and six key manhole shafts, known as the Melbourne Main Reliever (MMR).The majority of the MMR sewer tunnel is situated south of the Yarra River and will be constructed using an earth pressure balance (EPB) tunnel boring machine (TBM) and will be lined with precast concrete segments. The tunnel will be 2.4 m internal diameter and will have a 1.8 m diameter glass fibre reinforced plastic (GRP) sewer pipe positioned within it. This project represents the first large-scale, modern, mechanised tunnel project in MelbourneÆs Yarra Delta Quaternary sediments. There is little precedence known to the authors of similar scale tunnelling projects in these particular geological units. During the recent detailed investigation and design stages of the project, significant effort has been spent on characterising the geotechnical conditions along the alignment and predicting the effects of the new tunnel on the existing environment. Some of the key design issues that have been identified and managed through the design process include short-term surface settlement due to tunnel excavation and the predicted effects on surface infrastructure, potential spalling of the steel fibre reinforced concrete segments under full TBM ram loads and tunnel lining design in geological units with highly variable stiffness.Construction of the new MMR sewer tunnel is expected to commence in mid-2008 with a capital cost of approximately $160 million. Sewer system commissioning is scheduled for completion by early 2012.

Jan 1, 2008

A paper describing the treatment of the Mary Kathleen uranium ores must necessarily be historical and confined mainly to a review of the four papers which have already appeared. Couche and Hartley (1958) described the development of the treatment process just prior to the commencement of operations in June, 1958. Harris, Boag and Hemingway (1961) described the treatment during the operations, and Wreford (1965) reviewed all aspects of the mine and mill, when operations were suspended in November, 1963. Harris and Steele ('1960 presented a paper especially describing the radiometric sorting operation. Some hitherto unpublished information is also presented in the paper to describe some of the peculiarities of the ore, indicate reasons for the adoption of the treatment flowsheet, and some interesting problems connected with this treatment.

Jan 1, 1968

By M Wortley, A Cantarutti, T Ozkocak

The estimation of the grinding mill charge weight is vital to ensure its efficient performance. Mill underloading or overloading can cause losses through decreased production or unplanned down time. Metso Minerals Process Technology Asia Pacific and South America (MMPT) has developed two systems for measuring mill load. The first is an acoustic system (SmartEarÖ) and the second is an online model-based charge estimation system. The aim of both systems is to facilitate better operation of grinding mills. SmartEarÖ performs analysis on an audio signal from the mill and allows each different frequency component to be viewed, analysed and used in process control for load estimation. By isolating different frequencies, SmartEarÖ can give an estimate of mill load. The online dynamic mill model uses measurable mill parameters (such as power) to predict the current total load. Kalman filtering can also be utilised to further increase the accuracy of the model. Both of MetsoÆs systems have been installed at BHP BillitonÆs Cannington mine to measure the load within their autogenous (AG) mill. In this paper, the methods of mill load estimation are reviewed and compared to the bearing pressure reading, which is the current method used by Cannington to control mill load. The redundant estimates of mill load provide increased confidence and consequently more robust grinding operation under a wide range of conditions.

Jan 1, 2008

Some important mineral fields are referred to in discussing the formation of placer deposits in Australia. Testing methods include boring hand, with percussion rigs; with auger and pit digging drills; and l by vibro drilling. Sampling errors are minimized by the use of correct techniques and equipment for boring, sampling, and sample dressing, A hypothetical set of data is used to demonstrate the final process of evaluation, and some relevant taxation provisions are discussed.

Jan 1, 1964

By G W. Wilson, P Ritchie, N A. Currey

The design and rehabilitation of potentially acid forming (PAF) waste rock dumps is site specific, being a function, among other factors, of the rock types, the dumping and storage method employed, and the climatic setting. The æstore and releaseÆ cover system developed to manage acid rock drainage (ARD) from mineralised waste rock dumps at Kidston Gold MinesÆ open pit operations in the semi-arid climate of North Queensland, Australia, has been monitored for seven years. The paper describes the philosophy behind the design of the PAF dump and æstore and releaseÆ cover system and the adaptation of the cover system over time to suit KidstonÆs conditions. The results of monitoring over the seven years since the first cover was constructed are presented, and the approach being taken at Kidston to ensure that the risk of impacts from any residual ARD is accommodated and to facilitate lease surrender are described. The Kidston story is a valuable case study of a successful approach to remediating an identified source of ARD in a semi-arid climate, which has actively engaged all Stakeholders.

Jan 1, 2003

The Wellington Dam catchment has high value water, agriculture and coal and power generating resources. These conflicting land uses are managed through consultation and regulation. The Wellington Dam catchment is unique in that the Collie Coal Basin is located almost to the edge of the dam and has coal mining and power generation as its primary land use. Currently the dam is only used for irrigation due to its high salinity. The State Government has committed to reduce the damÆs salt levels to below 600 mg/L by 2015 so that it can be considered for public drinking water supply. The coal industry in conjunction with the community and State Government has worked together to enhance the water quality within the Wellington Dam to maximise its value and use by using mine dewater for industry, diverting saline Collie River flows, providing environmental (social) flows and enhancing water quality of mine voids to encourage new industry to the Collie Region. Both surface and groundwater in the coal basin are generally fresh, whereas the salinity in the Collie River East Branch generally ranges between 3000 to 20 000 mg/L and 1700 to 10 000 mg/L in the South Branch. Mine dewatering is currently two to three times greater than the recharge to the coal basin. As a result, all mine dewater is sent to power stations in the area, with excess discharged into drainage lines which flow into the South Branch of the Collie River. To maintain environmental and social flows some groundwater is also pumped to the South and East Branches of the Collie River during summer months. Completed mine voids are used for recreation and options for aquaculture are promising. However, handback criteria are yet to be finalised.

Jan 1, 2006

Investigations of the Mineragraphic Section; Commonwealth Scientific and Industrial Research Organisation, have included most of the known stannite-bearing ores in Australia, and have revealed several new occurrences of this relatively uncommon mineral. They provide information about its paragenesis, and its possible effect on tin recovery, that may be of general interest.Several of the investigations used in the preparation of this paper, were made in the first instance by pr. F. L. Stillwell or in collaboration with him.CASSITERITE-SULPHIDE ORES IN NORTH-WEST- TASMANIA Stannite is a minor component of most of the cassiterite sulphide ores of north-western Tasmania. These include the orebodies of Mount Bischoff, the Cleveland mine, Moina, the Stanley River district, Renison Bell, and the Heemskirk-Zeehan district, and form a well defined metallogenetic provence which is related to the Devonian granites of this part of Tasmania.In these ores mineralisation began. with deposition of cassiterite, a little wolfram, and quartz, topaz and tourmaline. With falling temperature, deposition of cassiterite ceased and arsenopy-rite, pyrite, and especially pyrrhotite, formed in abundance, tending to give massive sulphide ore. A little chalcopyrite; stannite, sphalerite and native bismuth accompanied the pyrrhotite. Deposition of quartz ceased after the pyrrhotite, was formed, and the later-formed nonsulphide gangue consists chiefly of carbonates and fluorite. With, the advent of the carbonates the pyrrhotite was altered to fine-gained intergrowths of marcasite and pyrite. Excess iron from the pyrrhotite entered the intergrown carbonate, or was precipitated as magnetite. Some solution of the cassiterite occurred at this stage, the tin being redeposited chiefly as stimnite replacement rims around the residual cassitellrite grains. Varying, but small, amounts of sphalerite, galena, tetrahedrite and silver minerals were depoSited at this stage, bringing the mineralisation to a...

Jan 1, 1951

CONTENTSSummaryIntroductionGeographical and Geological Outline of the RegionGrowth of the Mining IndustryTable 1: Production StatisticsGeneral GeologyRecent Alluvium and River GravelsSambeto SeriesMudstone and Basalt ContactVatukoula SeriesIntrusivesStructureGeologic HistoryLodesTable 2: Principal Lodes and Their OrebodiesMineral Assemblage and ParagenesisOre Shoots and Their ControlEmperor MineLoloma MineDolphin MineExplorationConclusionAcknowledgmentReferencesSUMMARYThe Tavua Goldfield was found in 1932 within a basin, both topographical and structural, near the sea on the north side of Viti Levu, Fiji, and has produced over £13,000,000 (Fijian) worth of gold and silver from the three mines...

Jan 1, 1953

By Remilton D, Raston GR

The low price of nickel which has prevailed since 1982 has dictated that unit production costs must be minimised. Early in the crisis, a decision was made within Western Mining Corporation to reduce unit costs by increased rates of production, not by a significant reduction in manpower. This paper details developments which have taken place at Kalgoorlie Nickel Smelter to enable the higher production rates to be achieved, or to increase energy efficiency. It is significant that most developments were achieved without the need for capital expenditure.

Jan 1, 1985

By M Denton, M Rheinlander, S Mundell, M Broadgate

The manufacturing industry reinvented its approach to the manufacturing process by managing and measuring it end-to-end. This improved returns on production assets, improved information quality and reduced delivery time, resulting in larger net profits through cost reduction and improved cash flow. Today this approach is standard in the manufacturing industry. Resource development has many requirements in common with the manufacturing production line. These include: control of the various steps, transparency of the state of the process to various levels of the organisation and the overall efficiency with which the process is executed. The authors argue that the introduction of manufacturing execution systems (MES) concepts and technologies to resource development processes will lead to similar improvements in control, transparency and efficiency and could improve profitability and enable staff to work more effectively and make better decisions.

Jan 1, 2009

By S Shipard

Filters are used in water treatment and hydrometallurgical process plants for objectives such as generating a dry spadable solid, pumpable high density slurry or high purity filtrate. The priority objective of every polishing filter, sometimes also termed clarifying filters is high purity filtrate and these are found in many diverse industries and even different applications within the same industry.To generate a high purity filtrate, process designers have the choice of many different polishing filter products, but in reality very few polishing filters are based on fundamentally different filtering concepts.This paper reviews the technology merits of well-known and the more recently developed polishing filter products and aims to assist metallurgists and engineers with the selection of an appropriate polishing filtration technology for pregnant liquor filtration and other process applications, plus a guide to best practice.CITATION:Shipard, S, 2013. Polishing filters for mineral processing plants, in Proceedings MetPlant 2013 , pp 118-125 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

By P Hollings, J Holliday

Porphyry copper, gold and molybdenum deposits form in subduction-related settings in association with calc-alkalic or alkalic magmatism. Hydrothermal alteration assemblages are zoned, with potassic cores and propylitic haloes overlain by extensive domains of clay alteration and silicification (lithocaps). Copper sulfides, gold and molybdenite typically occur in veins or hydrothermal breccias, and less significantly as wall rock replacements. Epithermal deposits may form above or to the side of porphyry systems, and may be juxtaposed into the core of a porphyry deposit if rapid uplift and exhumation occur through the life of the magmatic-hydrothermal system. Volcanichydrothermal breccia pipes (ædiatremesÆ) commonly form late in the life of a porphyry system. They may contain clasts of porphyry-style mineralisation, and can host significant epithermal gold resources. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By Riley S

Many regulatory bodies have, or are considering, guidelines that require rehabilitated mine spoils to be erosionally stable (satisfying quantitative limits) over specified design lifetimes. One of the problems facing the industry is that many of the computer models used for erosion assessment were developed for agricultural applications and are unable to predict the change in the shape of engineered landforms over extended periods of time. In particular, they cannot predict where valleys and gullies will develop in the landforms and how big or deep they will be. Furthermore, many existing models require considerable skill to use. A computer model (SIBERIA) developed by the first author, able to model this valley and gully development over long design lifetimes, and which is directly based on digital terrain maps is discussed here. Proposed rehabilitation strategies for waste rock dumps at Ranger Uranium Mine as assessed with SIBERIA are discussed. New features of SIBERIA of interest to the mining industry include the spatial distribution of erosion, deposition and gully development, and various measures of the quantitative risk of failure. A collaborative project with the Queensland Coal Association, involving the first author, aims to deliver these capabilities to the coal industry in a user-friendly package. The objective is the cost-effective rehabilitation of strip mines. Some preliminary results from this project are presented.

Jan 1, 1994

Blasting has been the most frequently used method for rock breakage since black powder was first used to fragment rocks, more than two hundred years ago. This paper is an attempt to reassess standard design techniques used in blasting by providing an alternative approach to blast design. The new approach has been termed asymmetric blasting. Based on providing real time rock recognition through the capacity of measurement while drilling (MWD) techniques, asymmetric blasting is an approach to deal with rock properties as they occur in nature, ie randomly and asymmetrically spatially distributed. It is well accepted that performance of basic mining operations, such as excavation and crushing rely on a broken rock mass which has been pre conditioned by the blast. By pre conditioned we mean well fragmented, sufficiently loose and with adequate muckpile profile. These muckpile characteristics affect loading and hauling (Scott, 1996). The influence of blasting does not end there. Under the Mine to Mill paradigm, blasting has a significant leverage on downstream operations such as crushing and milling . There is a body of evidence that blasting affects mineral liberation (Djordjevic, N, 2001). Thus, the importance of blasting has increased from simply fragmenting and loosing the rock mass, to a broader role that encompasses many aspects of mining, which affects the cost of the end product. A new approach is proposed in this paper which facilitates this trend æto treat non-homogeneous media (rock mass) in a non-homogeneous manner (an asymmetrical pattern) in order to achieve an optimal result (in terms of muck-pile size distribution)Æ. It is postulated there are no logical reasons (besides the current lack of means to infer rock mass properties in the blind zones of the bench and onsite precedents) for drilling a regular blast pattern over a rock mass that is inherently heterogeneous. Real and theoretical examples of such a method are presented.

Jan 1, 2001

The stratigraphic sequence west of Mount Isa contains the Judenan Beds, Eastern Creek Volcanics, and May Downs gneiss. It is an incomplete sequence as major north-south faults divide the area into four separatezones containing portions of these different units. The first three zones, which occur directly to the west of the Mount Isa Fault, consist of quartzites and quartz-mica schists which are uncorrelatable between zones but have been grouped together as the Judenan Beds. The most western zone contains an incomplete section of Eastern Creek Volcanics which rests conformably on a unit believed to be equivalent to the Mount Guide Quartzite; this is again underlain by the May Downs gneiss. A detailed description of the rock types is presented, but only a broad stratigraphic correlation is possible with the very much thicker sequence to the east of Mount Isa.The age of sedimentation is believed to be Lower Proterozoic and it may not occur in the type of geosynclinal basin envisaged by previous authors.This sequence is intruded by many small basic intrusions and also the Sybella Granite with its associated microgranite and pegmatites. The Sybella Granite consists of both a massive and a foliated phase; the latteris generally restricted to the margin of the main granite mass.Four regional metamorphic zones have been identified on the basis of their pelitic mineral assemblages; these are a chlorite, biotite, biotite-cordierite, and a sillimanite zone; separating each are prominent north-south faults.This metamorphism is a regional metamorphism which accompanies the first generation folding of the area and is not associated with the emplacement of the Sybella Granite. A very localized retrogressive metamorphism is also found in some areas of second generation folding.

Jan 1, 1972

The selection of the ore haulage system is one of the most crucial decisions made in the development of an underground mining project. The haulage system is, once selected, one of the components of a mine that defines its ability to respond to changes in mining inventory and the market conditions for its products. Over the last decade, in Australia at least, this selection process has largely centred on the debate over the merits of shaft and decline truck haulage. Little attention, if any, was given to the application of inclined conveyor haulage as a real alternative to the shaft and truck haulage. This is despite well established precedents for its application in the underground coal industry and some limited applications in underground metalliferous mines. This paper seeks to explore the case for the application of inclined conveyors as a legitimate ore haulage system for underground mines. The case for conveyor haulage is illustrated by an overview of the application of conveyors at some existing operations, and discussion of what conveyors have to offer as a mine haulage system and the issues that are associated with them. Material drawn from the feasibility studies for NewcrestÆs Ridgeway mine and Telfer Deeps Project is presented as case studies that considered selection of inclined conveyor haulage. The purpose of these case studies is to highlight the value of impartially approaching tasks of this type with a robust plan. This plan should be able to respond to issues identified as the task progresses towards the objective of finding the right solution for an ore haulage system.

Jan 1, 2005

Different mineral structures can act as mineral reservoirs for the immobilisation of toxic compounds. In the paper different mineral structures will be explained and their potential for incorporation of heavy metals and anions will be shown. The following structures will be explained (P÷llmann, 2007):apatites (incorporation of heavy metals, silicate apatites);ettringites (fixation of oxo-anions);layered double hydroxides (fixation of heavy metals, fixation of anions, fixation of organics, sorption materials); andmanganese oxides. Different possibilities of solid solution and incorporation in crystal structures will be explained and advantages of stable minerals be proved using experiences with real toxic wastes. In the process of thermal treatment the formation of primary mineral reservoirs will be shown. The precursor phases (similar to well known cement minerals) react in contact with water to form secondary mineral reservoirs (cement hydration mineral products). The formation condition of primary and secondary mineral reservoirs and their stabilities and incorporation possibilities will be shown. Examples for incorporation of various elements are given. Application for water clarification will be outlined.

Jan 1, 2008

By Stevenson C. H, Lynch A. J

The reasons for choosing autogenous grinding for the new Warrego concentrator of Peko Mines N.L. are discussed and the ores to be treated in the concentrator are described. The mill was designed on the basis of pilot tests carried out at Cobar and the performance of the mill has been most satisfactory both in its metallurgical and mechanical aspects. An empirical technique has been developed to predict mill performance for change in feed rate or feed size and a mathematical model of the mill is being developed for simulation and control work. The weight and size distribution of the mill load was determined at one set of operating conditions for use in the mill model.

Jan 1, 1974