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By G Senanayake, J Andreazza

The general experience in gold cyanidation research activities and plant practice is that high oxygen and cyanide concentrations improve gold leaching kinetics which in turn reduce residence time and increase throughput. This paper shows how the improved pre-oxidation method for the pyrrhotite rich gold ore of Bounty Gold Mine has increased gold recoveries at lower reagent consumption rates. The installation of a pipe reactor, in conjunction with a Multi Mix Systems oxygen injector, has lowered the amount of oxygen required to achieve a dissolved oxygen level target of 20 mg/L. The improvement of the pre-oxidation stage and lead nitrate solution addition has led to a reduction in the free cyanide concentration required for leaching, resulting in a decrease in cyanide consumption rate by 36 per cent to achieve a one to two per cent improvement in the gold recovery.

Jan 1, 2002

By A T. Owen, F A. Benn, J D. Swift, D M. Labbett, A F. Grabsch

The AMIRA P266 æImproving Thickener TechnologyÆ series of projects has sought to provide a firm scientific basis for feedwell and thickener design, a requirement as pressures on water usage in the minerals industry increase. While advanced computational fluid dynamics modelling of feedwell processes has generated the most obvious and successful applications to improving the performance of operating units, such outcomes have drawn heavily on parallel studies into flocculation fundamentals. Central to this has been the development of a linear pipe reactor system that allows the kinetics of flocculated aggregate growth and rupture to be measured for thickener feeds under turbulent pipe flow conditions. This ensures much greater control of the intensity and duration of applied shear than is possible with conventional flocculation test procedures, offering insights into flocculation processes that would be otherwise hidden in time-averaged measurements.

Jan 1, 2009

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 J J. Cilliers, K Hadler, A W. Stra

This paper examines the use of the FrothSim flotation simulator to improve the performance of an industrial column flotation cell. The performance of an industrial retreat column cell is simulated, and, from the discrepancies between the simulated and experimental results, a problem with the wash water distribution is postulated. The scientific reason for the reduced performance with uneven wash water addition is described in detail. Further simulations indicated the potential for improvement with an even wash water distribution, resulting in both improved performance and reduced wash water usage. The simulated uneven wash water distribution was confirmed industrially, and the headers were redesigned and installed. A sampling campaign to compare the performance before and after the modifications showed that the flotation performance was improved dramatically, with a statistically significant decrease in gangue recovery, without a commensurate reduction in valuable mineral recovery.

Jan 1, 2005

By Reid JG, Cutfield S

Considerable quantities of dissolved nickel are lost in the waste liquors from the QNPL nickel treatment plant. Cementation, precipitation and ion exchange techniques were investigated to reduce this loss. Ion exchange was the most successful of the procedures studied and a process for recovering nickel from stripped ammoniacal process liquors was developed in the laboratory and scaled up to plant flow volumes. The system developed uses a carboxylic ion exchange resin operated in a completely ammoniacal cycle. The regenerant is itself regenerable using existing plant, thus the only loss is the stoichiometric value of NH4+ required to displace the exchanged cations from the resin. Existing plant sand/anthracite filter beds have been adapted for use as resin columns containing 3 cubic metres of resin capable of treating effluent at a flow rate of 6000 litres/min.

Jan 1, 1978

By Phillips H. R

The action of free rolling disc cutters is well understood, relationships between disc geometry and performance having been established both in the laboratory and under field conditions. However, under severe operational conditions a malfunction of the disc bearing assembly is likely to produce a definite change of cutting action. Collapsed or siezed bearings can even prevent the disc from rolling and thereby create what is equivalent to a drag pick. This paper describes a programme of laboratory experiments using deliberately stalled discs. Their performance under such conditions is contrasted with that for a free rolling disc and also with a drag pick having a ridged front developing into a negative radiused back clearance angle. In conclusion an assessment is made of the influence stalled discs can have on the torque and thrust requirements for a tunnel boring machine.

Jan 1, 1981

By Higuchi K

For the mechanisation or automation of mining, recognition of the shape of mined cavities is basic information. A three dimensional shape measuring system, developed and tested, includes an ultrasonic range finder which is attached to the tip of a serial link manipulator. The range finder can be moved to any position and direction in the operational space of the manipulator. The position of a point on the surface of the object is obtained from the position of the range finder, the direction of the beam of the ultrasonic waves and the measuring distance of the range finder.To avoid collision between the sensor and the object, the manipulator is controlled to trace the surface of the object For the tracing control, another ultrasonic range finder is employed. The test results show that the developed system has high performance.

Jan 1, 1991

By Anderson RJ

Tower Mills are used at Aberfoyle's newly commissioned Hellyer base metal sulphide concentrator. Hellyer ore is particularly fine grained. To achieve adequate liberation fine grinding is necessary. Three Tower Mills are used on regrind duties, grinding to less than 20 microns. The physical arrangement, material flows and grinding characteristics for the Hellyer Tower Mills are described. The mills have performed satisfactorily, both in size reduction and power efficiency. Wear parts must be inspected and changed more often than with ball Mills. To date, 92 per cent availability has been achieved. As parts and maintenance routines are rationalised, this is expected to improve to 96 per cent. Modifications to wear parts for the Hellyer Tower Mills are discussed.lhc Tower Mill grinding environment is highly reducing. The impact of Tower Mill regrind on downstream flotation is discussed.

Jan 1, 1991

By Mortensen JK, Lang JR

The Canadian Cordillera contains numerous classic porphyry deposits and several unusual subtypes, including the alkaline suite of porphyry Cu-Au deposits and the Tombstone magmatic suite and associated Au¦W deposits. The alkaline suite formed in collisional settings in island arcs whereas the Tombstone suite was emplaced in an active fold and thrust belt in a continental arc. In addtion to different regional settings, these suites differ in the type of underlying basement, metallogeny, and the styles of mineralization. Both magmatic suites were emplaced over short intervals, probably in response to specific tectonic events. In the case of the alkaline suite, the tectonic event promoted magmatic processes suitable for the formation of porphyry Cu-Au deposits. The tectonic environment is less well constrained for the Tombstone suite, but the result was the formation of distinctive porphyry and intrusion-related Au¦W deposits.

Jan 1, 1995

Rajasthan of western India blessed with rich base metal and phosphorite deposits. The biogeochemical and geobotanical methods of mineral exploration are greatly used in parts of Rajasthan Zawar, Khetri and Ambaj multi-metal project Gujarat and Jhamarkotra phosphorite deposit. These principles are exclusively based on certain assumptions about the anomalous chemical composition in plants and distribution and migration of indicator elements. Biogeochemical studies for lead zinc deposit of Zawar group of mines were carried out to locate the probable accumulators which could help in prospecting for these metals. The important roots of Impatiens balsamia plants contain 735 mg. of cadmium and crotolaria linifolia 603 mg., melhania futteyporensis 626 mg. lindenbergia muraria 443, celosiu argentia 360 mg. In the Khetri copper belt the vegetation is scanty and the species includes Acacia arabica, zyzypus jujuba and cactus euphorbia.

Jan 1, 1988

Copper refining electrolytes are maintained in the range 60-65¦C to ensure an efficient operation. The heat energy required to meet these temperatures has been traditionally derived from the electrical energy required for the electrolytic process and supplementary steam energy. In 1983, experiments were conducted at Copper Refineries Pty. Ltd. (CRL) to determine the effects of insulating the Tank House cells, and fully covering the cells. The results of these experiments showed conclusively that greatly reduced steam consumption would be required to maintain electrolyte temperatures. These positive results led to an Energy Conservation Programme for the Tank House, and this was implemented in 1984. A computerised cell cover monitoring system was developed, and is used to control cell coverage and fluid balance. The experimental work and the benefits obtained since implementation of the programme are discussed.

Jan 1, 1985

In both exploration and mining, the laboratory is often seen as a cost rather than a profit centre. The aim in most mining companies is to increase profits by reducing costs, so the budget for the laboratory is under constant pressure.There is another option; to see the laboratory as the brain of the operation. By lifting the status of the laboratory and treating it as a profit centre, mine costs may be reduced in other ways, e.g. reduction in milling costs. This change of status will require investing more capital in better equipment, more training for employees and more employees to carry out project research.There are many examples of major costs being incurred because of inadequate laboratory work. Conversely, by spending more money on laboratories and their activities, overall costs can be reduced or profits enhanced.

Jan 1, 2002

The paper describes some of the economic and human factors associated with haulroads on Mount Whaleback, a large open pit iron ore mine. These factors have combined to encourage formation of a specialised road maintenance crew which caters for haulroad construction and maintenance. Techniques used for design, construction, operation and management of haulroads are then described. Future developments are expected to effectively lower construction costs leading to an even wider application of the techniques described and consequent improvement in temp- orary roads and overall truck performance. INTRODUCTION Mount Whaleback is a large truck/shovel open pit iron ore mine located in the Pilbara region of north Western Australia. Annual production capacity exceeds 100 million tonnes per annum of waste and ore. The truck haulage fleet comprises WABCO 120 52 WABCO 3200 22 74 of which approximately 45 are operating at one time.

Jan 1, 1982

By J Naser, M Tuck

This paper reports a computational study using computational fluid dynamics (CFD) in a mine ventilation system. Ambient air is injected to a rectangular mine drive through a circular duct. Moisture evaporates from shaft wall depending on flow properties of air in the drive-duct system. The physical process involves simultaneous momentum, heat and mass transfer. A species transport equation is employed to account for the moisture concentration in air. The momentum equation is solved using standard k- model, while energy and species transport equations are solved using standard expressions for moisture evaporation rate and heat flux from the drive wall. The aim of this paper is to investigate effectiveness of CFD simulation in relation to mine ventilation in a drive where a significant mass transfer phenomenon occurs. Results from simulation are compared with existing data from a site in Victoria.

Jan 1, 2005

Mining and metals projects have tended to increase in both scope and cost to a point where many projects are Droperly designated as superprojects. Specialist engineer- constructors have developed organisations and systems to provide project management services during the design and construct phase of large projects. However, the engineer-constructor is also required to provide a wide spectrum of services during the evolution of large projects prior to the construction phase. Some common phases of pre-construction evolution are identified together with the associated types of specialised services which may be required. A project management team approach is described which has been developed for the design and construct phase. It is suggested that a modified matrix organisation could be adapted to the provision of special- ised services as well as to project management for ore-construction phases of the project.

Jan 1, 1980

Australia is a leading producer of mineral sands and according to U.S. Bureau of Mines, produced 24, 53 and 64% of world's production of ilmenite, rutile and zircon respectively in 1983. The industry which is mainly export oriented earned in export income about $210 million in 1985. The dominant position which Australia occupies in world produc- tion of mineral sands is also maintained in many areas of research and development work on the processing and application of these minerals. Some of this research which is leading the world has been responsible for setting up industries to produce value-added and high-tech products such as synthetic rutile and partially stabilized zirconia (PSZ). The production of high purity zirconia is due to commence shortly while research in rare earths offers an exciting prospect for future Developments.

Jan 1, 1986

By A C. Robertson

Over the past decade there has been continual change in the way that mines have been managed and the component roles of those people who make up the total mine management system. Major issues have included the change in the business structure of mining companies, the change in on-site infrastructure, increased personal liability of managers for the safety and health of employees and increasing social and environmental pressures on managers and their staff. This paper looks at the changing roles of two of the many groups of professionals associated with the mining industry - the equipment supplier and the mining consultant. The profiles of the ACME Group Pty Ltd, suppliers of ventilation equipment and ancillary canvas and plastic products to the mining and construction industry, and Tennent, Isokangas Pty Ltd, Consulting Mining Engineers, are presented.

Jan 1, 1998

By M H. Randell, J B. Haines

The Honeymoon Uranium Project comprises the Honeymoon Deposit,Goulds Dam Deposit and Yarramba Prospect in the Southern Lake Fromeregion, South Australia. Both the Yarramba Prospect and HoneymoonDeposit (which includes Honeymoon and East Kalkaroo orebodies) arelocated in the Yarramba Palaeovalley. The Goulds Dam Deposit is about75 km north west of Honeymoon, in the Billeroo Palaeovalley. Exploration for sediment-hosted uranium began in the area in the late1960s, culminating in the discovery of Honeymoon and Goulds Dam inthe early 1970s. In 1982, a 25 L/s demonstration plant was built atHoneymoon to confirm suitability for in situ leaching. The project was put on hold in 1983 due to changes in government policy. Southern Cross Resources Australia Pty Ltd acquired the project in mid 1997. Roll-front deposits form from a migrating geochemical cell, anadvancing reduction-oxidation interface between oxygenateduranium-bearing groundwater and its reduced aquifer host. The source of metal is uranium-anomalous granites, which were eroded fromsurrounding ranges. The weathered granites and resultant sediments are stripped of uranium by oxidised groundwaters, to form solutions carrying uranyl carbonate complexes. The solutions percolate down-slope through permeable sand zones until contacting a reduced environment where uranium precipitates. Uranium mineralisation occurs interstitially between and as thin coatings on sand grains, usually in the form of uraninite or coffinite. The palaeovalleys (previously termed palaeochannels) are incised intounderlying Cambrian/Precambrian basement rocks and filled withsemi-consolidated, largely un-cemented, Tertiary sediments of the Eyre Formation. The late Palaeocene to middle Eocene Eyre Formation is the basal unit of the Tertiary succession in the Callabonna Sub-basin of the Lake Eyre Basin. Further to the north, the Lake Eyre Basin overlies the Jurassic-Cretaceous Eromanga Basin, which comprises much of the Great Australian Basin. Eyre Formation sediments are in turn overlain by the late Tertiary Namba Formation and terrestrial Quaternary units. At Honeymoon, the Eyre Formation includes immature, pyritic,carbonaceous sands and gravels interbedded with lignite andkaolinite-illite-montmorillonite clays. It was deposited by braidedstreams during epeirogenic uplift of the Olary Ranges, accompanied bysubsidence of the Lake Eyre Basin. The Eyre Formation comprises aconsistent stratigraphy of interbedded sand and clay units that arecontinuous over the Honeymoon Deposit but with local variationindicating some hydrological connection between aquifers.In the Honeymoon orebody, uranium occurs within coarse-grained,pyritic sands where the basal sand pinches out between overlyingcarbonaceous clay and the southern palaeovalley slope. Its characteristics are typical of the well-developed, planar limb of a roll-front uranium deposit. Zonal changes related to the reduction-oxidation interfaces across the deposit are readily observable. The orebody extends for nearly 1000 m along the valley margin, is 400 m wide at its maximum and averages about 6 m in thickness. The East Kalkaroo orebody also lies near the southern margin of theYarramba Palaeovalley. It extends discontinuously for approximately 3.5 km and averages 200 m width, with significant uranium present in the Middle as well as the Basal Member. The Billeroo Palaeovalley extends northward for 40 km sub-parallel tothe western side of the Benagerie Ridge, is up to 5 km wide and hasgently dipping banks. Eyre Formation within the palaeovalley isconcealed beneath 90 m of Quaternary and Namba cover, isapproximately 40 m thick, and is sub-divided into three upward-finingunits, which are remarkably similar to the Yarramba Palaeovalleysequence.

Jan 1, 2001

By S Johnston, L Howe, S Stevens

Regulators have an important role to play in fostering and enabling reliable, effective, environmental management. Given this, it is perhaps surprising that there has been relatively little debate on exactly how regulators can enhance their own approaches, in order to promote improved outcomes overall. The authors argue that applying research on High Reliability Organisations, as well as the University of Pennsylvania’s Penn Program Framework for Regulatory Excellence, to regulators has the potential to facilitate positive environmental results across the mine life cycle.

Aug 2, 2023

By S N CARRAS

Ore reserve estimation is a procedure involving data collection, data storage and judgement and assumptions about geology mining and metallurgy. Calculations are based on these assumptions and an economic analysis on projected cash flows is carried out. Ore reserve estimation must therefore be subjective and will always depend on the extent to which the assumptions used in arriving at the estimate are correct. This paper is an attempt to summarise the many aspects that can contribute to ore reserve problems and to offer some suggestions on how to minimise these problems. For further details on specific concepts readers are referred to the detailed descriptions in the referenced papers.

Jan 1, 1992