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By Govett G. J S, Currie D. A, Cohen D. R

Analysis of mechanical size fractions of soils around the Paddington deposit (W.A.) and the Charters Towers Goldfields (Queensland) shows a bimodal gold distribution, with enrichment in the coarsest and finest fractions; this is probably a common feature of soils in arid terrains. To establish the true distribution of Au within the soil fractions, the effect of bulk Au content and percent weight variations in size fractions can be reduced by a normali- zing procedure. The greatest extent of lateral dispersion of Au recorded in the -125 ¦m fraction at Paddington and the -63 ¦m in the Charters Towers area as compared to the coarser fractions, and increas- ed levels of sample representivity in the finer fractions, favours their use in exploration. If orientation studies indicate the preferen- tial use of coarse or intermediate fractions, only wet sieving can quantitatively dis- aggregate the clays and remove finer contamina- ting material. The collection of extremely fine fractions such as the -63 ¦m is also accelerated by wet sieving. The additional costs of wet sieving may be offset by better interpretation of results through increased analytical sample representivity, anomaly contrast and continuity.

Jan 1, 1988

By Wilson AC

Permian coal from Western Australia's only producing coalfield at Collie is the dominant fuel used in generating electricity for the State's interconnected grid. Collie coal is sub-bituminous, non-coking and has a low ash, medium volatiles and high moisture content. The seams were laid down in a fluvial basin which extended beyond the Collie Basin and included the Wilga and Boyup Brook Basins at least. Adjacent parts of the southwest Yilgarn Block are prospective for Collie-type basins. In the past few years significant deposits have been delineated within the Perth Basin, specifically on the Vasse Shelf and in the Hill River area. In the former area high quality steaming coals are correlated with the lowest coal bearing member at Collie. The seams are amenable to underground mining and because of their high quality, the coal may have export potential. Sub-bituminous coal deposits of Jurassic age are present in the Hill River area. Exploration has down-graded the prospectivity of the Carnarvon and Canning Basins for sub-bituminous near-surface coal deposits. Tertiary lignite deposits are present in palaeo-drainage systems in the southern part of the State and their potential for development is being evaluated.

Jan 1, 1986

Although laterite ores already provide a significant proportion of the world's nickel and cobalt production it is anticipated that they will surpass sulphide ores as a source of nickel in the next century. The most recent period of greenfield nickel project construction was during the 1970s when it was notable that all of the eight new plants were based on treating laterite ores. This was because of the relatively large selection of available high grade laterite ore deposits amenable to cheap open cast mining and a paucity of high grade sulphide ore prospect alternatives. Of the three processing options for treating laterite ores: 1. smelting for the lower horizon saprolite ore, 2. ammonia; and 3. acid leach for the upper horizon limonite ore, smelting currently accounts for about 80 per cent of nickel production. In the future, as saprolite ore grades decline because of relatively high exploitation rates, the incentive to process the large untapped reserves of limonite ore will increase. The high cobalt content of limonite ore also makes it ideally suited to processing by a hydrometallurgical rather than smelting route. With only two exceptions, all saprolite smelting operations have a Class 2 nickel end product (largely ferronickel) and do not produce a cobalt by-product. As a result of technological advances, the modified ammonia leach process for limonite and transition ore as undertaken at Yabulu, now allows the production of pure nickel metal as a Class 1 product, along with significant tonnages of cobalt by-product. The mixed Ni-Co sulphide intermediate product of the pressure acid leach processing of limonite ore at Mon is converted to Class 1 nickel and cobalt metal at Fort Saskatchewan, Canada.

Jan 1, 1996

By P K. Seccombe

Sulfur isotope data are available for 18 low-sulfide orogenic gold systems hosted by the Lachlan Orogen in eastern New South Wales including those in the northern Hill End Trough (Hargraves, Hill End, Napoleon Reefs, Sofala-Wattle Flat, Stuart Town, Windeyer) and adjacent areas (Bodangora, Lucknow, Springfield), the Gilmore Fault Zone (Adelong, Sebastopol) and those in the Parkes district (Calarie, London-Victoria, Wyoming One-Myall United). Other systems for which data are available include Mongarlowe, Murrumbateman, McMahons Reef and Yalgogrin. The d34S data for many of the larger deposits including Adelong, Bodangora, Calarie, Hargraves, Hill End London-Victoria, Lucknow, Sebastopol, Sofala-Wattle Flat, Stuart Town and Windeyer (Group 1) are all very similar and have average d34S values close to zero per mil. Near 0ë d34S signatures imply that sulfur was sourced from a magmatic reservoir. Furthermore, the large Wyoming One deposit has d34S values significantly below 0ë with the data implying that sulfur was sourced from a fractionated magmatic reservoir. Group 2 deposits include those at Mongarlowe, Murrumbateman, Napoleon Reefs, McMahons Reef and Springfield . These deposits have average d34S values significantly above 0ë. With the exception of Springfield where sulfur was probably sourced from the Hill End Trough, Group 2 deposits are an order of magnitude smaller than Group 1 deposits. The results suggest that many of the larger orogenic-related gold deposits hosted by the Lachlan Orogen in eastern New South Wales derived sulfur and gold as a result of leaching and recycling from a magmatic reservoir. Alternatively, there may have been direct mantle-derived input; however, this is considered unlikely on geological grounds. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By E Haren, A Winchester

The CSA Mine has a long and varied history from initial discovery in 1871 through to the present. Lead-zinc mineralisation was mined historically near the surface. Today copper and silver are extracted from the deeper regions of the mine. The mine has passed through a number of owners over this time, each with a unique operating philosophy and understanding of the mineralisation. Cobar Management Pty Ltd re-opened the mine in 1999 and has undertaken extensive drilling programs to expand the resource and gain a better understanding of the mineralisation characteristics. Presently mineralisation has been located over a strike length of 1.2 km and to a depth of over 2.0 km with over 30 mineralised lenses from four identified ore systems. The refinement of geological and mineralisation models led to further discoveries and prompted a review and modification of resource modelling processes. Advanced statistical analyses prompted the implementation of ordinary kriging as a grade estimator. Improved stationarity from enhanced geological domaining has been supported by variography and kriging neighbourhood analysis studies. Resource models at CSA are now quantifiable in terms of mineralisation style and estimation reliability. The new techniques are assisting the definition of more mining fronts, which are creating new opportunities to increase mine output.

Jan 1, 2006

Broken Hill has a long history of mining and it is without doubt a world-class deposit. It has seen production since 1885, notwithstanding the strikes that made the city infamous in days gone by and has given rise to three of the nation's leading mining companies; BHP, North and CRA. Prior to the formation of Pasminco in 1988, the mining and exploration activities were undertaken by separate companies who were business competitors and tended to operate in relative isolation. There were a few notable exceptions such as the Central Geological Survey of 1936 - 38 (Gustafson, 1939; Gustafson et al, 1950) and the Mine Managers' Association. The latter sponsored many university based research projects. At a local level there was good communication and cross fertilisation within this remote outback centre through personal contacts and professional bodies such as The AusIMM. Pasminco was formed by the merging of the lead-zinc interests of CRA Ltd and North Broken Hill Ltd. In Broken Hill this meant the joining together of North Mine and ZC Mines, the two largest mines then operating on the Line of Lode, to form Pasminco Mining Broken Hill Operations. The exception was the central part of the orebody, the original BHP, South Mine and

Jan 1, 1997

By Derham DW, Newcombe LA

The operations of the Mount Morgan gold tailings retreatment plant were significantly improved in 1984 by the desliming of the CIP plant feed, which reduced cyanide consumption and increased percent gold dissolution. Subsequently, the development of slimes treatment, incorporating gold leaching from slimes solids by copper cyanide complexes in the process water, and gold adsorption on to carbon in an environment lacking free cyanide was successfully implemented. Mount Morgan was initially mined for gold commencing in 1882 on the auriferous ironstone cap to the sulphide ore body. During the history of mining and processing at Mount Morgan the operations have developed through numerous phases of gold and copper production, operating almost continuously through until the final closure in late 1990. The final phase of processing was the retreatment of tailings, predominantly flotation tailings accumulated since the 1930s, for the recovery of gold and minor silver. Tailings retreatment commenced in 1982 with the commissioning of a 10 000 tonnes per day CIP plant to treat some 40 million tonnes of tailings at an average grade of 1.08 g/t Au. The initial operations were hampered by high cyanide consumption and poor gold dissolution on the mixed siliceous/pyritic tailings. The successful development and implementation of the desliming of the CIP plant feed in 1984 (as described by Parsons and Hampshire, 1986) reduced cyanide consumption by 40 per cent, and raised gold extraction by 13 per cent points by virtue of significantly higher dissolved oxygen levels. The finer portion of the reclaimed tailings were deslimed by eighty 100 mm diameter AKW cyclones, with the desliming cyclone overflow thickened in a Warman 30 in diameter thickener for water recovery and slimes disposal. Operation of the desliming plant involved the discarding of a slime fraction representing about 15 per cent of the reclaimed feed. Although gold-bearing, the high content of cyanicides and oxygen consumers within the slime negated any conventional treatment of this stream with free cyanide for gold recovery. The natural lixiviant behaviour of the soluble copper cyanide complexes for gold, which was extremely evident at Mount Morgan, directed efforts in this area. Enhancement of gold leaching with a deficiency or near absence of detectable free cyanide, but with significant levels of copper cyanide complex from recycled process water were examined. Adsorption of this solubilised gold onto carbon in a similarly difficult environment required close examination.

Jan 1, 1993

The use of scrapers in mining and earthmoving operations is not new; in fact they are one of the earliest methods of bulk earthmoving. A single machine, which can load, haul, and dump material with a minimum of ancillary support is a highly productive and cost-efficient method of earthmoving. In recent times scrapers have been unpopular due to perceived problems and operational limitations, but the last couple of years have seen a resurgence in the use of scrapers in the Bowen Basin as a primary prestripping tool. The main operational limitation of scrapers is the economic operating range. Maximum productivity and lowest cost per bcm is achieved on short leads, as the lead distance increases the cost per bcm quickly reaches and then overtakes that of an truck-excavator fleet. The geometry of a ætraditionalÆ coal mine does not readily allow short leads for prestrip fleets due to the nature of dragline stripping operations. The strip arrangement means that material has to be taken around the end of the pit, meaning a longer haul distance than the actual point-to-point distance between load and dump. This can be alleviated by using pit bridges, however these can cause spoil problems for draglines if not properly planned and have been avoided by many mines. Due to the economic haul distance limitation of scrapers, truck-excavator fleets have become the normal method utilised. Currently more geologically complex mines are opening up, which do not allow traditional down-dip strip mining to occur. Cross-dip mining methods allow for short leads between prestrip loading and dumping areas, hence scrapers and bulk doze are realistic alternatives to a truck-excavator fleet in the prestrip environment. Keeping the lead distance to a minimum a fleet of 657Æs can move material at a very low cost. The other main operational limitation of scrapers is the type of material that can be economically excavated. Hard material can lead to damage to the bowl, free-flowing sand will not readily stay in the bowl leading to reduced load factors. Ripping the material with a dozer prior to excavating can lead to improved loading time, and greatly reduced GET consumption. When considering scrapers for prestrip operations a number of things must be considered: is the lead distance within the economic haul distance? should twin power (push-pull) or single power (dozer pushed) scrapers be used? do I need to rip, what should I rip with? what ancillary support is required? is there another system already available on-site which is currently under utilised? This paper considers the parameters under which large twin power scrapers are the most effective way of undertaking prestrip operations.

Jan 1, 2003

In 1953, Dr N Fisher of the Bureau of Mineral Resources, acting on behalf of the Society of Economic Geologists, which is considering the sponsoring of a uniform system of nomenclature for ore reserves, enquired from The Australasian Institute of Mining and Metallurgy whether it had ever considered this subject and particularly whether it had ever set up any standard definitions or specifications with regard to ore reserves.As this had not been done, but was thought to be desirable, the Council of The Institute appointed a Committee consisting of H H Dunkin, Associate Professor of Mining Engineering, University of Melbourne (Convenor); E A Rudd, Professor of Economic Geology, University of Adelaide; J D Campbell, Chief Geologist of Western Mining Corporation; and the writer, to consider the report on this subject.In December 1953, the Committee submitted its frrst report to the Council and this report (reproduced here as an Appendix) was widely circulated among member companies and engineers, with an invitation to comment on the proposals. A large number of replies was received and studied.After studying the replies the Committee issued a second report, in part as follows:From these replies we have learned that the suggestions made in the frrst report of the Committee are unacceptable to most of those interested, on one or all of the following grounds:a. number of categoriesb. defmition of categoriesc. nomenclature.It is also apparent that all alternatives suggested in the various replies would likewise be unacceptable to the majority of those replying.As a result, we have come to the conclusion that neither this Committee nor any other could at present and in the present state of opinion on the subject make recommendations regarding classification and nomenclature of ore reserves which would be acceptable to a sufficiently large proportion of members.It seems to us now that the objective of a widely applicable and acceptable system of classification and nomenclature, one that could be endorsed by The Institute and ultimately become standard practice in the industry, requires more than compromise between present conflicting views... it requires first a foundation of substantial agreement on the essential facts, implications and range of ore reserve estimation. This does not yet exist and it is evident that much additional analysis of present practice and opinion must be undertaken before any further systhesis is attempted.

Jan 1, 1994

It is not often that mines have as much warning of the approach of bad ground conditions as was the case at the Western Mining Corporation, Kambalda Nickel Operations Lafranchi/Schmitz Decline. Most aspects of this operation are in fact quite unique and like the best solutions, the answer to the problem of weak and foliated ground conditions was relatively simple; requiring the use of readily available explosives although the idea of using it in this manner may not be the most obvious.The use of high shock energy POWERGEL 2131 cartridges proved to be the correct answer, in conjunction with small changes in drill pattern design. The resulting lack of overbreak bears testimony to the success of the concept and the commitment of the miners to achieving a safe working environment.

Jan 1, 1992

By M J. Kelleher

CREAM is an acronym for coal recovery, evaluation, analysis and management and is a business improvement project at BMAÆs Goonyella Riverside mine that is focussed on maximising coal recovered. In August 2003, Goonyella Riverside was set a challenge to quantify coal loss and dilution and their relationship to cost, revenue and ultimately profit. While the mine was confident in its site forecasts of recovery (and loss), it was clear that the traditional measurement and analysis systems were inadequate to firstly, identify key loss areas and mechanisms and secondly, successfully quantify the benefit of various coal recovery initiatives. The path that BMA Goonyella Riverside has travelled to maximise coal recovered can be divided into four key steps: Mapping the process û This step involved the development of a coal flow process map for Goonyella Riverside that stepped through each component of the process from the coal reserve to the customer and identified key measurement points for the purposes of reconciliation. Understanding coal loss and identifying opportunities û This step involved conducting two detailed Reserve to Customer projects at the mine site to track a block of coal from the reserve to the customer and to gain a greater understanding of the relationship of dilution, coal loss mechanisms, revenue and costs associated with recovering additional coal. Coal data systems development û Two important coal data systems have been developed and implemented at Goonyella Riverside in the past twelve months, namely SnowdenÆs Coal Reconcilor and SeamFix. These systems enable coal losses and dilution to be quantified and reconciled back to the initial coal reserve. Implementation of loss reduction initiatives û This step involved the formation of a business improvement project referred to as æCREAMÆ in August 2004, for the purposes of improving pit coal recovery and maximising business value. To date a series of coal recovery trials have been run in a number of pits at Goonyella Riverside that have yielded significant improvements in business value. The key to the success of this project has been the discipline to follow a defined process map, management commitment through resourcing and shared key performance indicators, a successful acceptance strategy resulting in holistic ownership and the implementation of sustainable reconciliation systems. Coal loss and dilution are now quantifiable and their relationship to cost, revenue and ultimately profit is well understood. This paper discusses the process that Goonyella Riverside has adopted to maximise coal recovered.

Jan 1, 2005

By K G. van den Boogaart, S Konsulke, R Tolosana Delgado

Adaptive mineral processing has to rely on spatially predicted information on primary geometallurgical parameters, like phase composition, size and shape distributions of grains from various phases, portions of value elements in different grain types. Naively, one would predict these parameters geostatistically and select an optimal processing for the predicted structure. This is suboptimal, due to various kinds of non-linearities in the problem. First, some primary geometallurgical quantities themselves are measured in non-real scales, like compositional or stereologically distorted geometric information. Standard geostatistics has to be replaced by compositional and geometric geostatistics, involving complex transforms and restrictions. Further, only partial and uncertain information is available, introducing a stochastic character to the optimisation problem. Moreover, many response variables leading to costs, outcomes and eventual effects of later processing depend non-linearly on the primary geometallurgical parameters, which implies that the final monetary value is not estimated unbiasedly by kriging. Finally unbiased linear prediction (such as kriging) is not the best method of prediction for decision making. The conditional expectation of the monetary values is needed instead. The impact of these problems is explained in this paper, with simplified examples, and a first approach to a general solution is proposed. CITATION:van den Boogaart, K G, Konsulke, S and Tolosana Delgado, R, 2013. Non-linear geostatistics for geometallurgical optimisation, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 253-258 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

A mining joint venture presents a real management challenge to achieve harmony with the other participants in the successful development and operation of a mine. This can best be facilitated by a detailed agreement and guided by a set of joint venture principles which recognise the differences of the interests of the parties and seek to establish sound business and personal principles by which differences not anticipated in the agreement might be resolved. The major and minor co-venturers can and do present potential difficulties to one another. This paper, one of the pair in the joint venture panel discussion session, predominately presents the minor's viewpoint. Usually commercial matters such as project finance, areas of interest, divestment, pre-emptive rights and decision-making can be adequately covered in the agreement. However, when the parties disagree and have difficulty in resolving their differences, the joint venture principles should be used to advantage to resolve relationship difficulties.

Jan 1, 1997

By Swann CA

In order to meet export sales requirements from 1983 onwards, Amcoal developed a new underground mine in the Witbank area of the Transvaal. The mine was required to produce 5 million tons of run of mine coal per annum giving rise to 4 million tons of saleable products. A description of the coal processing plant is given with comments on design philosophy and design parameters. Main features of the coal processing plant are the raw coal handling facilities, centralised control and data capture and the loadout station. The management systems applied during the commissioning period are described. The difficulties experienced and their solutions are discussed. Commissioning was concluded with an independent plant performance test.

Jan 1, 1986

By Johnston S

A blending trial was conducted on 60 per cent Perseverance/40 per cent Rockys Reward underground ore at WMC Resources Leinster Nickel Operations to compare the benefits between batching and blending treatment of the two ore sources. Milling, f

Jan 1, 1997

By Virtanen M

Grinding has been one of the areas of major development at Outokumpu's concentrators. During its early years the company used entirely rod and hall mills, but due to the high costs of metallic grinding it began the testing of autogenous grinding as early as the 1950s. In the late-1970s, the company's own modification for two stage autogenous grinding was ready for industrial use. Surprisingly late, in the 80s - 90s, an interest rose to check also the effects of grinding methods on flotation results. This paper firstly gives a short history of the development work of Outokumpu type autogenous grinding, called 'Outogenius'. The effects of some grinding methods on the process results of two nickel ores are then reviewed. The tests to date show notable effects of grinding methods on flotation.

Jan 1, 1996

The current drill-and-blast method of tunnelling is cyclic and, for this reason above all others, has a future application potential which is lower than that of continuous methods. There is scope for progress in several facets of today's drill-and-blast tunnelling. But even if each of its unit operations and the synthesis of these were to be optimised, this conventional method will, in the long term, fail to be a serious competitor for tunnelboring machines (TBMs), roadheaders and the like. If its role in tunnelling is not to decline at an increasing rate, drill-and-blast will need to be transformed into a continuous system. Boring and cutting machines consume considerable energy (and expenditure) in creating rock fragments which are smaller than those required by muck-handling equipment. In this respect, blasting is more efficient. Mechanical methods are also less versatile and flexible and, when planning proceeds on a basis of meagre or inadequate geological data, cannot be costed as accurately. Currently, research gains for TBMs and roadheaders are greater than those for conventional tunnelling. If (as is likely) the disadvantages of mechanical methods continue to be reduced at a greater rate, the swing away from drilling and blasting will gain momentum.

Jan 1, 1987

By Milawarma E, Cusack C

The Sapan Dalam coal deposit of Indonesia consists of ten steeply dipping seams with thicknesses varying between 0.1 and 3.5 m and split by shale, clay, silt and sandstone. The area contains four faults dipping about 75¦ with four to 85 m vertical displacements. The complex nature of the deposit coupled with limited 27 exploration drillholes at an average spacing of 200 m made it difficult to create a realistic geological model. A three-dimensional gridded seam model gave a fair representation of the deposit. Attempt to create an optimum pit using the WHITTLE 3D pit optimiser proved unsuccessful since the pit optimiser is restricted to standard regular or fixed blocks. The gridded seam model was converted to a fixed block model prior to the optimum pit design. Smoothing and pit base controlling were also introduced to obtain a smoother pit. A mining scenario produced 3.6 million tonnes of coal, 28.4 million bcm of waste and US$18.1 million revenue.

Jan 1, 1995

Rehabilitation has been very effective in the short to medium term in providing a cost effective and reliable means of containing the side effects of land disturbance. However, there is still insufficient data to critically evaluate the sucess of rehabilitation in the long term. There is an urgent need to develop objective criteria to monitor the sucess of rehabilitation. The aim of rehabilitation in Australia has traditionally been to return disturbed land to natural vegetation compatible with the surrounding area. This objective has often been accepted instinctively without adequately addressing alternatives.

Jan 1, 1992

An increase in the silver to gold ratio with increase in depth in the main ore shoot of the Crown- Crescent lode in the Emperor gold mine, Fiji, was found to be due mainly to vertical zoning of gold-silver tellurides. The zoning resulted from

Jan 1, 1980