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By Sheer T. J

The increasing demand for underground cooling in South African gold mines has resulted in various cooling methods being con- sidered, including the use of ice. Two main areas in connection with ice cooling systems are being investigated. The first concerns the efficient and cost effective production of ice on a larger scale than previously required for any other application. The second con- cerns the transportation of ice in pipes from surface ice-making machines to underground melting sites.

Jan 1, 1988

By Braaksma M, Dudley K

The Girilambone Copper Mine is located in central New South Wales and has been operational since May 1993. Girilambone is operated by the Girilambone Copper Company (GCC) which is a joint venture between Straits Resources (60 per cent) and Nord Resources (40 per cent). The mine complex consists of an open cut pit, ore crushing and stacking, heap leaching, solvent extraction (SX) and electrowinning (EW) allowing for the recovery of 14 600 tpa of LME grade A cathode copper. The leaching and SX-EW plant have been described previously by Rear, Taylor and Busby (1994) and Miller (1994).

Jan 1, 1996

By Ahmed M, Leung L

A program of microseismic noise monitor ing for gas outbursts, in conjunction with other mining engineering measurements and observations, is being undertaken at Leichhardt colliery in Queensland. Headings are developed at present by shotfiring. The equipment being used in this study includes piezoelectric accelerometer assemblies to detect microseismic noise which is then transmitted to a surface base station by cable. Data are recorded on an analogue magnetic tape recorder and are also analysed on-line using a commercially-available acoustic emission pulse analyser. It is proposed to re-interpret recorded data using various modes of analysis and to interface a desktop computer to the existing system to permit continuous monitoring on the mine site. No outbursts have been recorded or analysed and only a limited number of develop- ment shots, and the resultant microseismic activity, have been recorded to date.

Jan 1, 1980

By Hungerford F

Long-hole drilling technology has rapidly advanced this decade beginning with rotary drilling/pump down camera surveying and culminating in down-hole motor drilling with cableless electronic surveying over the past two years. With the latter system, a high level of directional control is achievable in boreholes up to 1000m long. Past long-hole drilling across the industry has seen a mixture of success and failure. With these experiences, new and improved techniques and equipment have evolved. A number of long-hole drilling options are available as variations on the basic rotary and down-hole motor methods. They involve different levels of cost and equipment and vary in their suitability in different geological environments and definition of targets. Long-hole drilling is mainly target applied, either in defining geological structures in greater detail, or proving important mining areas such as longwall blocks, to be free of structures. Successful drilling hinges on a combination of drilling expertise, quality and appropriateness of equipment, understanding of geological conditions and good colliery support. Drilling expertise forms part of sound interpretation through keeping relevant records, understanding the reasons for changes in drilling conditions and implementing specific tests such as coring. The final interpretation builds upon all other available geological information. There is still scope for research into improved techniques and equipment. The use of long boreholes for geophysical surveys has high potential.

Jan 1, 1988

By W A. van der Westhuizen

Selective mining played a major role in saving a mine and a communityÆs existence as well as creating a working culture that is the model for all KumbaÆs mines. The successes that resulted from selective mining led to receiving KumbaÆs highest award (it was the Gold Medal Breakthrough project of 2003) as well as the productivity award at the National Productivity Institute award ceremony in 2004. Kumba was established in November 2001 (previously Iscor Mining). The new company identified Mineral Resource Management (MRM) as one of its key drivers and an initiative was launched to define MRM in the Kumba way. Best MRM practices at the Kumba mines were included in the definition. Selective mining was born out of this initiative. One of the key principles of good MRM practice was identified as: æThere must be a balance in the operational processÆ. This principle was applied with great success at Thabazimbi Iron Ore mine in the Limpopo province, South Africa. The emphasis of this paper will be to show how value can be unlocked throughout the whole mining value chain. In the past (up to 2001) the mine went through a number of crisis situations: planned production performances were not reached, the stripping ratio was extremely high with two new pits, the product beds were not of constant quality, slope failures were big risks, flooding could and did cut off half of the ore supply, and restructuring demoralised staff.This paper focuses on: selective mining throughput drivers, and selective mining and its role in achieving this balance.The results were dramatic, with huge improvements in production results, stockpiles, plant yields and product bed specifications. The mine was brought into balance and a self feeding loop was created with positive spin-offs up to this day.

Jan 1, 2005

By Rashchenko AF, Voiloshnikov GI, Elshin VV, Khomutov VV

The sorption method for the precious metals recovery fromsolutions and pulps are a perspective trend of modernhydrometallurgy. Russian gold mining industry uses thesemethods, anion-exchange resins being applied as sorbents. Theanion exchange resins allow effective recovery of preciousmetals, however, they have several drawbacks as compared withactivated carbons: high cost of sorbents; difficulties arisingduring treatment of pulps with complex ion composition;necessity of using titanic equipment and thiourea for gold elutionfrom loaded anion-exchange resin and its regeneration.

Jan 1, 1993

By Radmuller H

The proposed underground mine at Porgera forms an integral part of the Porgera Joint Venture project in Enga Province in the remote Highlands of Papua New Guinea. The total in-situ reserves are approaching 400 tonnes of gold making the Porgera deposit one of the largest in the world. The remote, rugged and inhospitable terrain, recent unstable geological environment and primitive yet socially complex nature of the densely populated local community, combine to make the Porgera project very different to developing mines in Australia. The Porgera project is a challenging and exciting mining exploration venture in the final stages of feasibility study submission and negotiations with the National Government of Papua New Guinea. A 1476 m exploration adit was driven in the footwall of the high grade mineralisation for diamond drilling purposes as part of the evaluations necessary for the feasibility study. Ground conditions encountered have ranged from weak mudstones with high water content, requiring immediate steel set support, to competent intrusives.

Jan 1, 1988

By R Vleggaar

In addressing a short-term operational need for the relocation of a tailings storage facility reclaim pond, a mine has achieved a host of water management objectives. Through effective planning and adoption of a strategic æwhole of mine lifeÆ approach, the mine has achieved significant environmental, social and economic benefits. A review of all water management aspects across the site identified a host of other interrelated water issues and concerns which, if dealt with individually, would prove too costly for individual operational departments. When considered as a whole, however, the issues became opportunities and provided the stimulus for integration of the site water management system. The development of site water and solute balance models provided the tool by which a number of water management options/strategies could be evaluated. The conceptual design and costing of the proposed water infrastructure further facilitated the evaluation of the multiple benefits to be gained from each option. A business case could then be made to mine management for the preferred option. The recommended water management strategy finally recommended to the mine not only provided a tailings storage facility (TSF) reclaim pond, but also provided for:increased wastewater recovery from the TSF, the capture of all waste rock dump run-off, additional water harvesting from local creeks, increased wastewater reuse, improved environmental water management, infrastructure that could be used by the local community after mine closure, and overall cost savings. This paper illustrates how effective water management planning can provide both short-term economic and environmental benefits, as well as long-term social benefits.

Jan 1, 2006

By C F. Prins, C LantuTjoul

Mineralisation in alluvial diamond or vein gold deposits is often hosted in trapping mechanisms. For instance, diamonds are nested in bedrock depressions such as gullies and potholes which were carved out by the sea long before the diamond deposition took place. Similarly, gold mineralisation can precipitate in the necks of a boudinage structure. In such deposits, the spatial distribution of the mineralisation is governed by the mutual arrangement of the trapsites and by the grade variations within each trapsite. Reliable estimates can be obtained only if they rest on a proper knowledge of both degrees of variability. This creates a challenging sampling problem, as during the exploration phase it is important to have a good global mean estimate to enable decision making towards the future. A similar problem occurs for local estimates at a later stage of development. To understand and manage the sampling for global means, specific sampling procedures are required based on an appropriate choice of sample support size and spacing. Estimates from such sampling campaigns should be unbiased, and the less variability they display, the better the sampling parameters. The performance and impact of sampling parameters are tested and compared on different simulated deposits.

Jan 1, 2005

The Prominent Hill copper-gold deposit is located approximately 150 km north west of Olympic Dam, on the southern margin of the Mount Woods Inlier in South Australia. Its discovery in November 2001 resulted from the application of a geological model developed from geological, geophysical and petrophysical data pertaining to the Olympic Dam deposit. The discovery has dispelled the notion the Olympic Dam may be unique, and that another deposit like it is unlikely to be found. The Prominent Hill mineralisation is hosted by haematite-matrix hydrothermal breccias, which have suffered extensive iron-sericite-silica alteration and overprinting. Copper, gold, barium, fluorine, uranium, cerium and lanthanum are all intrinsically associated with the hydrothermal iron. Breccias intrude an east-west striking, fault-controlled sedimentary succession, which is flanked to both the south and north by volcanic complexes. Many similarities between Prominent Hill and Olympic Dam are documented including geological setting, mineralogy, breccia styles, and alteration. Differences relate largely to the nature of the immediate host rocks. The similarities and difference provide key data for improving exploration models for this style of iron oxide copper-gold deposit, both within the Gawler Craton as well as globally.

Jan 1, 2004

At Pasminco Mining's South concentrator. which was commissioned in 1952. an expansion. modernisation and efficiency improvement program commenced in 1986 with a coarse ore stockpile and grinding circuit expansion. the replacement of small flotation cells and the upgrading of reagent mixing and metering equipment. The program continued with the installation of a TDC 3000 based process control system (1988) and concentrate thickeners (1990). By mid-1991 a further grinding expansion and the installation of zinc flotation feed regrind ball mills and zinc recleaner column cells will be complete. leaving the use of ceramic disc fillers and development of process control strategies as probably the remaining major avenues for improved process efficiency at present.

Jan 1, 1991

By Smitham J. B

A selection of Australian washed coal samples was examined to determine the effect of sample hydrophobicity (rank) and particle size on froth stability in the flotation process. The results indicate distinct rank-based variations in froth volume and stability for flotation tests conducted without the use of collector, over a series of particle size distributions.High-rank coals showed a greater tendency to generate stable, high-volume froths than coals of lower rank. Implications for circuit design and operation are outlined.

Jan 1, 1988

Geostatistical analysis, resource estimation and three-dimensional modelling of the gold grade distribution was undertaken using exploration drillhole data taken from the Mt Leyshon gold mine. The main aims of the project were to provide an independent estimate of the primary gold resource and to improve the estimate by better understanding the statistical distribution of gold and the establishment of more robust variograms. These criteria have been achieved by the removal of low grade sub-populations, increased sample size and access to data from the most recent drilling program. The outcome of this statistical study has led to a lowering of the sill and nugget variance of the variograms used. Distinct geometric anisotropy was identified in all the resource estimation zones and was used to model gold grade distribution.Two independent resource estimates were established from the primary gold resource, one based on a geostatistical estimator (kriging) and the other on a traditional estimator (inverse distance weighting). Both methods were compared with a contemporary kriged estimate by Mt Leyshon Gold Mines Ltd.

Jan 1, 1993

Access to the Rosebery Orebody, which dips into the western slopes of Mount Black at 45¦, has been achieved in sequence by the following means: - A series of adits down to 8 level - An inclined shaft (No. 1 Shaft) sunk internally from 8 level to 14 level - A vertical circular concrete lined shaft (No. 2 Shaft) sunk internally from 4 level to 19 level. Although the orebody has been fairly well defined to 19 level, deeper ore occurrences have been outlined by a series of drill holes decreasing in frequency with depth to 26 level. No. 2 Shaft (sink) was stopped some 10 m below 19 level in order to make an early start on doubled production at West Coast Mines, with the intention of subsequently extending the shaft or of driving a decline from the lowest operating horizon for deeper access. The decline approach was adopted some six years after production commenced from No. 2 Shaft. The reasons for that decision are outlined, together with an account of the constraints and design requirements imposed by commencing by a vertical shaft in the hanging wall of the orebody.

Jan 1, 1982

By J Vann

The key functions of project evaluation are to assess potential profitability and to develop an effective operational design. For mining projects, design aspects include mining methodology, ore treatment methodology and production rates. All of these characteristics impact on project economics and overall value. Resource models, which form the ultimate basis of project evaluation, typically consist of tonnes above cut-off, grade above cut-off and the spatial distribution (connectivity) of tonnes/grade above cut-off, for one or more variables. Dilution, ore loss and metallurgical recovery are all modifying factors applied to the resource model during evaluation and determination of profitability. A key issue is: how is the value determined? In addition to traditional combination of in situ tonnes/grade, the following merit serious consideration: the concentration of deleterious elements, throughput rates, mining/processing costs and û importantly û metallurgical recovery. Geometallurgy is an emerging field targeted at integrating these issues by identifying either direct measures or proxies for throughput (hardness, grindability), recovery (liberation, mineral shape/texture, etc) and concentrate quality from easily collected macro-, meso- and microscopic data. These ægeometallurgical variablesÆ drive project costs and revenues in a fundamental way. For geometallurgical characterisation to have a real impact on business design, it must enable improved mine planning. When creating spatial estimates for such variables, it is preferable to find proxies that can be measured as close to the intact rock mass as possible. However, spatial estimation of proxies for geometallurgical properties and responses is complex and requires special consideration. Unlike grades, both proxies and absolute measures of geometallurgical variables are not necessarily linear or additive and therefore require very careful geostatistical consideration. In some cases, models must predict extreme values of geometallurgical attributes rather than averages. Incorrect characterisation of metallurgical recovery/throughput can (and has) led to misspecification of the scale of projects, and thus can be seriously value destructive. Aspects of geometallurgy have long been important in iron, bauxite, manganese and coal deposits and are increasingly on the radar for base and precious metal miners. However, as more metallurgically complex deposits are developed and mining of large-scale, low-grade deposits becomes more commonplace, the importance of characterising the metallurgical response in order to generate properly optimised projects will rapidly increase. It is possible that in many ætraditionalÆ (ie grades and tonnes) reserve models, the variables that drive the project are missing!

Jan 1, 2007

By Mathew P. J

The CSIRO Division of Mineral and Process Engineering in Melbourne has been developing on-stream analysis sensors based on neutron and gamma radiation for better control of quality and process operations. This has resulted in the development of Ironscan, an on-stream analyser that measures the iron content of both lump and fine iron ore on conveyor belts. It can be mounted under existing conveyors with minimal modifications to the conveyor structure and can cope with steel cables in the belt. An interface gauge and an on-stream coal ash analyser have also been developed, both based on measurement of natural radioactivity. The interface gauge monitors the interface between liquor and mud in thickeners and washers, provided the natural radioactivity of the mud is sufficiently high to detect it above background. The natural-gamma ash gauge is a valuable addition to the Coalscan range of ash gauges. It is applicable to heavily laden coal conveyors or bins where the coal bed thickness exceeds 30 cm, and also to lightly laden conveyors, provided the coal is profiled on the conveyor.

Jan 1, 1991

By Xu C

This paper describes the structure and operation of an interacth.. computer program for mineral industry financial analysis and production planning. It includes comprehensive risk analysis with correlated variables and optimal production scheduling using Lane's balancing cut-off grades and the general dynamic programming approach.

Jan 1, 1995

By D Cotnoir, Q Liu, D Richard, M Ourriban

The difficulty in fine particle flotation has been attributed, among other things, to a low bubble-particle collision efficiency. Many technologies have been developed which aim at increasing bubble-particle collision efficiency, either by generating micro bubbles or by enlarging particle sizes. However, commercial applications of these technologies are limited. Over the last five years COREM has been actively testing fine particle froth flotation technologies with the objective of commercialisation. Several fine particle flotation technologies, such as dissolved air flotation, electro-flotation, floc flotation, selective flocculation-flotation and carrier flotation, were tested on both single minerals and ore samples in order to identify the reasons that prevented these technologies from being used on a commercial scale. It was found that the two most noticeable factors that prevented the successful application of these technologies were: Mechanical entrainment of fine gangue minerals. This was a general problem in fine particle flotation, but was aggravated by these technologies that either generated micro bubbles or enlarged the sizes of hydrophobic particles. Oxidation of (sulfide) minerals that resulted in hydrophilic oxidation product coatings. The oxidised fine particles could not be recovered by these fine particle flotation technologies effectively. Solutions to the two problems, ie gangue entrainment and fine particle oxidation, were proposed and tested. It seems that polymeric depressants with both depression and flocculation functions could significantly reduce gangue entrainment, and hydrophilic surfaces of oxidised fine particles could be modified by high intensity conditioning or controlled sulfidisation, thus increasing the recoveries of fine valuable minerals. The improved fine valuable particle flotation and reduced fine gangue entrainment along with fine particle flotation technologies resulted in much improved flotation separation of fine particles.

Jan 1, 2005

By Noreen D

At Bougainville Copper Limited comparison testwork was conducted between "horizontal" cycloning and conventional vertical cycloning. Horizontal cycloning reduces circulating load and allows increased ball mill throughput. Cyclone efficiency is the same or better as a result of the reduction of fines short-circuiting to the underflow. Operationally, horizontal cyclones are less likely to suffer from blocked spigots and high cyclone feed pump sump levels. Cyclone feed pumping power is reduced. High horizontal cyclone underflow density provides the option to optimise grind by manipulating water addition to the ball mill feed.

Jan 1, 1988

By S Pigram, G J. Jameson

This paper is concerned with the tracking of particles in the froth phase of an aerated water/glycerol mixture. Experiments have been carried out in a specially designed laboratory flotation cell that allows formation of a deep froth. Phosphorescent tracer particles of various sizes were injected into the centre of a froth column where they were excited by ultraviolet lights, positioned at the back and front of the column. The motion of particles was captured on a digital camera with a green filter. The images from the digital camera were then transferred to a computer and an image analysis program was used to convert the colour intensity to the concentration of particles at each location within the froth. The tracer technique was used to determine the dispersion of hydrophilic particles and the variation of the concentration of solids with axial and radial positions.

Jan 1, 2005