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The purpose of this paper is to look at the costs of tailings disposal, and in particular the comparative costs of different disposal methods in different situations. Costs are often the hidden design parameter. We know that they are important but sometimes feel that it is not very respectable to talk about them in public. It is better from a public relations point of view for it to appear that the decision-making process is driven by environmental factors or best practice rather than looking for the cheapest option. But this presumes that the two are mutually exclusive and this need not be so. These issues are discussed later in the paper. It is also commonplace for the scale of the mining operation to change with time, typically involving increased throughput rates and total tonnage. New ideas in tailings disposal make their appearance. The regulatory attitude can change. Having made a decision about the disposal method at the time of original feasibility study and design it is easy to suppose that the mine is æstuck with itÆ. But that also need not necessarily be so. Careful costing of options may reveal that a switch in method could be cheaper in the long run. The designer will often tend to think in terms of initial earthworks and site development costs. Aspects of power consumption, labour, and periodic campaigns to move tailings pipelines and carry out embankment raises are either overlooked or not given the same emphasis. This can distort the evaluation process. It is productive to think in terms of dollars or cents per tonne as a basis of comparison, not just the total sums. Tailings disposal can cost from as little as 10 - 20 ó/t to over $1.00/t which is a big range. There may be good and unavoidable reasons for the high figure but there would need to be to justify being so far over the industry average. At the same time, mining and processing costs, at least for gold, are around $15 - 20/t. Viewed from this perspective tailings disposal will always be a relatively small component of the annual budget.

Jan 1, 2000

The paper continues an account, begun in a previous paper, of experimental work carried out by the author whilst a member of the metallurgical staff at the Cockle Creek Works. The general method of the description of the plant and works practice adopted previously has been followed.The paper is a short account of the methods used in and the results of an investigation of the fume losses from the various parts of the plant.MEASUREMENT OF VOLUMETwo independent methods were used. The first depended on a number of pitot-tube measurements of velocity. These readings were taken in the stacks leading from the various furnaces at a considerable height above the ground so as to obtain as regular conditions as possible at the points where the readings were taken.Three openings were made in each stack and the pitot tube inserted into each opening in turn and readings taken at the centres of imaginary areas of equal size. The average velocity in the stack was thus obtained.After four tests had been made at the smelter stack, which removed the gases from all blast furnaces in use, the centre of velocity of the gases for each test was calculated and was found to be practically constant in position. The previous procedure was varied in subsequent tests on this stack by taking a succession of readings at the centre of velocity instead of at various points...

Jan 1, 1925

By D Hart

In 1944 some ten or so pieces of legislation impacted on the mining industry. Today in excess of 80 in one way or another apply to the Northern Territory miner. This paper will look at the nature of the legislation that has been introduced and the reasons for its introduction. During the Second World War the mining of resources such as iron, tin etc for the war effort set the platform for the subsequent expansion of the industry in the post-war years. Thereafter, the change in attitudes over the years that have resulted from a more conscious public and more responsible governments and developers associated with the recognition of the legal rights of others and the threat of litigation, will be traced. With a major review of the Northern Territory Mining Act currently in progress, this paper will view ANZMEC's foreshadowed preference for a National Code and the NT's intent of drawing some commonalities with other states of Australia to achieve this aim. Finally, the questions of over-regulation and whether existing legislation is complete will be addressed. From this it is foreshadowed how legislation may develop during the lead into the 21st century.

Jan 1, 1994

With the burgeoning opportunities for new gold mines to be developed the opportunity now exists for a reassessment of the optimal processing path for these gold ores. Projects have traditionally followed the path of whole ore cyanidation with either Carbon In Pulp (CIP), Carbon In Leach (CIL) or Merrill Crowe. The challenge ahead is whether these traditional processing methods are the best option for stakeholders, or to go beyond CIP and use a combination of currently available technologies that can be used to provide gold recovery at a significantly reduced capital cost and minimal deleterious impact on the environment. Either stand alone or combinations of gravity concentration and flotation, can produce a gold bearing concentrate that can then be fed directly to a batch or continuous intensive cyanidation unit. Treatment of a gravity/flotation concentrate by intensive cyanidation may be processed by the InLine Leach Reactor (ILR) developed by Gekko Systems of Australia. The advantages of the technology combining gravity/flotation followed by intensive cyanidation are significantly reduced capital costs; improved safety due to reduced cyanide inventories; the majority of tailings un-contaminated by cyanide; less energy required due to an opportunity for an increase in grind size û reducing green house gas emissions; detoxification of concentrate tailings can minimise tailings disposal and containment requirements.

Jan 1, 2004

By Dredge K, Becker G

The successful dissolution of the valuable metal components of a solid phase is often a basic requirement for a successful hydrometallurgical treatment process. Sulphide concentrates are often an intermediate product in the production of refined metals. These concentrates need to be further processed to realise the contained metal values in a useful form. Pyrometallurgical techniques have tended to dominate, at least the initial treatment of metal sulphide concentrates. The technology described, Activox«, has been developed specifically for the hydrometallurgical treatment of these sulphide mineral concentrates, in particular those containing copper, nickel or gold. The Activox« dissolution technology coupled with the use of existing, or newly developed, downstream processing techniques, offers alternative processing options for the recovery of full value, saleable metal products. The technology is suitable for application down to relatively small scales opening up the opportunity for on-site production of metals even at modest scale mining Operations.

Jan 1, 1995

Backfil ling of excavated Sub Level Open Stopes has been underway since March 1989 and as at December 1992 some 1 100 000 cubic metres of Cemented Aggregate Fill have been placed. During these three years significant developments in fill quantities, types and cost have taken place.Operational improvements have reduced the quantity of Cement Aggregate Fill by 40 per cent. These results have been achieved by:ò rescheduling stopes,ò designing smaller primary stope, and ò use of uncemented rockfill.Unit cost for Cement Aggregate Fill have fallen in the order of 50 per cent through:improving fill hole reli ability,simplified barricade construction procedures, reducing the cement content,ò substituting dune sand for deslimed mill tailings, ò improved maintenance at the Backfill plant, and ò renegotiated site freight agreement.This paper will review the historical developments of backfill use at Olympic Dam.

Jan 1, 1993

By G D. Richmond, J C. Chomley

Copper has been mined intermittently at Gunpowder, north of Mount Isa, since 1927. Most ventures have had some initial success but fluctuating copper prices, the small-scale of the operations and the remoteness of the site led to closures or sale. Processing routes have included direct sale of high grade ore, flotation of oxide and sulphide concentrate, and copper cement production from mine solutions. Copper cathode has been produced by heap and in-place leaching coupled with solvent extraction and electrowinning (SX/EW). Aberfoyle Limited recently purchased the Gunpowder operation and is expanding operations. An innovative high recovery tank leaching process, including a low temperature, low pressure autoclave, has been adopted. Copper cathode will be produced from an expanded solvent extraction/electrowinning plant at approximately 45 000 tonnes per year. The combination of expanded throughput and high metal recoveries will make Gunpowder a cost competitive producer.

Jan 1, 1998

By P Hofmeyr, D Pretorius

Iron ore, which is transported by rail from the iron ore mines at Sishen in the Northern Cape, to the Saldanha Iron Ore Terminal in the Western Cape, needs to be analysed while loading to be exported. Every shipment will be sampled and an average analysis of the ore will be produced which is required by the purchaser at the receiving port. On arrival at the iron ore terminal at Saldanha, the ore is tipped from the rail trucks onto conveyor belts to be either stockpiled or direct-loaded. The conveyor belts run under the sampling plant and the ore is sampled periodically by means of an automated cross-belt sampler. This is the first iron ore port sampling facility in which the automated sampler is situated above the conveyor belts and not adjacent to them. A portion of the primary sample taken off the belt is moved to the dedicated sampling laboratory situated behind the cross-belt sampler and over the conveyor belt lines. The sample is split in the laboratory, one split being used for moisture and particle size determination and the other part is dried and then analysed by means of X-ray fluorescence spectrometry (XRFS) on fusion beads for major and minor elements. Particular care is taken to obtain high quality data for penalty elements.This sampling plant is completely automated and from the primary cross-belt sampler to final analysis by XRFS no manual steps are involved. This has meant that some processes are used which are suitable for automation and are ISO compliant but not necessarily ISO-certificated. The ISO manuals were developed with manual laboratory processes in mind. Precautions are also taken to maintain the integrity and representativity of the samples. This paper is a case study?describing?the automated sampling systems used at the Saldanha Iron Ore Terminal sampling facility and laboratory from conveyor belt to analysis.CITATION:Hofmeyr, P and Pretorius, D, 2012. Automated sampling of iron ore for analysis at the Saldanha Iron Ore Terminal in South Africa, in Proceedings Sampling 2012 , pp 25-32 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 21, 2012

By KenGemar P, Perembo R. C B, Winn R. D

The New Guinea orogen comprises terranes that have accreted to the northern margin of the Australian craton. The history of the accretion of terranes begins earlier (in the Late Cretaceous) and is more complex than has been suggested previously. There was a collision in the central highlands in the Late Paleocene or Early Eocene, and a Finisterre collision that precedes and is distinct from the later (Pliocene) Bismarck volcanic arc collision.

Jan 1, 1997

By C Smith, R I. Maczkowiack, P D. Erskine

Open cut coal-mining has been conducted in the Bowen Basin region of central Queensland for almost five decades, and has disturbed an estimated area of 140 000 ha of agricultural land until 2011. Approximately one-third of the area disturbed by mining has been rehabilitated to pastures or bushland. However, none of the rehabilitated land has yet been assigned a specific end-use. This research project develops an approach for assessing end-use risks for the regionÆs mined land, and develops risk assessment models for selected end-uses. First, a web-based survey of stakeholders was used to identify risks to be assessed. The risks identified were surface erosion, subsurface erosion, bushfires, weeds and feral animals. The survey also identified possible end-uses of bushland and grazing. Second, conceptual risk models were developed based on the risk assessment concepts of likelihood and consequence specified in the Australian and New Zealand risk assessment standards. Likelihood was modelled using site characteristics and management factors that influence the occurrence probability of risks (eg surface erosion), while consequence was modelled using a set of site condition indicators and condition thresholds (changes in root-zone water-holding capacity, soil erodibility, vegetation ground cover and soil organic matter and transition probability to a non-preferred ecosystem type).The factors influencing likelihood and consequence for each risk have been integrated using Bayesian networks. The next step in model development is to parameterise the Bayesian networks using existing equations, empirical datasets, or expert opinion where data are not available. The parameterised models will be used to assess grazing and bushland end-uses against erosion, bushfire, weed and feral animal risks for rehabilitated mined land sites, with the purpose of identifying the relative risks associated with each end-use, and the landform design specifications and land management practices under which end-use risks are minimised.CITATION:Maczkowiack, R I, Smith, C and Erskine, P D, 2012. Risk assessment models for post-mining land use, in Proceedings Life-of-Mine 2012, pp 33-42 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

INDEX OF CONTENTSBlast Furnace SlagsForehearth AccretionsConverter SlagsConclusionsIllustrationsCOMPOSITION OF SOME COPPER SLAGS FROM PORT KEMBLASamples of copper slags from the Port Kembla Smelter of the Electrolytic Refining and Smelting Co. of Australia, Pty. Ltd., have been submitted for mineragraphic examination, with reference to the mode of occurrence of copper in them. The samples included (I) blast furnace slags, (H) a forehearth accretion, and (IH) converter slags. 1. BLAST FURNACE SLAGS Four series of samples of blast furnace slag have been submitted. The. chemical compositions of the several slags are shown in Table 1. Analyses Nos. 1 and 2 are of samples of slowly or normally cooled slag, taken from the slag dump, Analyses Nos. 3 and 4 are of samples comprising slowly or normally cooled slag, together with granulated slag from the same melt.

Jan 1, 1949

Coal washing practice can be improved not only by critical examination of the plant being operated but also by studying plants operated in other areas. The developments at the Australian Iron & Steel Pty. Ltd. plants are discussed in relation to experiences there as well as developments which have taken place in Queensland in recent years. Early A.I.S. problems involved small coal cleaning in heavy medium cyclones and flotation. A proposed future plant flowsheet for A.I.S. is considered in the light of these experiences. Reference is made to plants operated by the Thiess, Peabody, Mitsui Coal Company Pty. Ltd. at Moura and the Utah Development Company's plants at Blackwater and Goonyella in the development of coal washing prac- tice in Australia.

Jan 1, 1975

The region we call the West Coast is acknowledged as one of the richest and most diverse mineral provinces in the world. It's the most rugged part of Tasmania and our island is one of the most rugged parts of Australia, so that speaks for itself. A hostile land of razorback mountains, deep ravines, dangerous rivers, almost impenetrable rainforests and a climate that can change from mild to freezing in a matter of hours.

Jan 1, 1993

By Griffiths L, Marshall P

fhis paper describes investigations into drainage of gas from the solid to control outbursts. Initial studies conducted on drainage of shear zones showed that, given enough time, these can be successfully drained. Once drained, they can be intersected and driven through without any activity of outbursts. The results of programme of investigations to determine parameters for drainage from the solid show that gas flow rates from the Bulli Seam on the average are about 2 litres/min/metre length of borehole. But when shear zones are intersected, the flow rates could be as high as 8 litres/min/ metre length of hole. Shear zones can be picked up from pressure measurements 50 - 60 m away and this could give sufficient time to drill through these zones and drain them in advance. Systematic drainage of Bulli Seam at West Cliff Colliery could eliminate or reduce frequency of outbursts considerably. At present drainage holes are being drilled systematically in the seam, with drainage installations on the surface. Gas purity of 80% methane is being delivered at the surface plant.

Jan 1, 1980

By D MacKenzie

The Rise & Shine Shear Zone is a shallow-dipping Cretaceous late metamorphic shear zone formed in a compressional environment. The Shotover mineralised system is dominated by normal faults with well-defined vein systems that cut across Miocene schist folds and faults related to the inception of the Alpine Fault. Despite the geological differences between these mineralisation systems, they share many common features of hydrothermal alteration that have resulted in disseminated gold in altered sheared schist. The most distinctive feature of both systems is the abundant ankeritic carbonate that has formed from decomposition of metamorphic chlorite. Excess iron from this alteration reaction combined with hydrothermal sulphur to form sulphides that host the disseminated gold. The chlorite decomposition reaction was reversed in the latter stages of both mineralisation systems, and this was accompanied by further gold emplacement in the Rise & Shine system.   Both alteration systems involved initial decomposition of metamorphic albite, followed by deposition of albite as a vein mineral in the latter stages. The fluid flow that yielded the disseminated gold was controlled by microshears that pervade host schists, in strong contrast to many Otago Schist vein systems where host rock alteration is absent. The ankeritic alteration in the Shotover and Rise & Shine mineralised systems has increased the volume of mineralised rock, and may have made suitable targets for large-tonnage, low grade gold deposits.

Jan 1, 2007

Cyanide-extractable gold is far more meaningful in the definition of ore, and control of extraction, than fire- assayable or aqua regia digestible gold. The use of cyanide- extractable gold addresses the significant problems of over- as well as under-assaying by fire and aqua regia digests. The problems of conventional control or diagnostic cyanidation extractions: lengthy extraction, and masking by pregrobbing in cyanidation extractions for assay purposes; are surmounted with a novel activator - Leach WELL. Full extraction of liberated gold, insignificantly affected by preg-robbers, can now be achieved within 30 minutes. This can assist in reducing common gold losses presently often hidden by inappropriate mine call factors, and/or high grade cut values. This paper includes a discussion of fundamental mechanisms of cyanidation, preg- and assay-robbing, which underlie the phenomena Involved.

Jan 1, 1992

By D FitzGerald

A critical component of any new tunnel design in a complex geological setting is the development of an integrated three-dimensional (3D) geology model with a full set of geotechnical properties of the rocks present. A novel means of predicting the geology based upon sparse observations of structural geology at the surface and from drill holes has been developed and used in several major tunnel studies in Europe.An example of this is the Lyons-Turin twin rail tunnel which is still in a development phase. This tunnel has been in planning and development for over 15 years already. An important aspect of this work is to characterise geological uncertainty along various possible tunnel paths as an input into early design optimisations for time, cost and risk avoidance strategies. Once the tunnel works commence and more detailed geological data is collected by daily mapping, progressive refi nement of the geological model is desirable; geological conditions still to be encountered can be more accurately predicted. Faults and their offsets, dykes, geological unconformities, folding, as well as standard sedimentary processes are all correctly modelled in the software. It is important to allow for seamless interchange of geological models at various scales with CAD workflows so that sufficient detail can be readily accessed at the required scale. Also, the proposed tunnel in its correct geometry can become a ‘section’ in its own right. Progressive detailed local geology models in the vicinity of the advancing head are created from the regional scale work by cutting and pasting a starting model, then adding all the extra detail for the required engineering geology work.For all rocks, most standard geotechnical quantities such as sonic velocities, Young’s modulus and Poisson’s ratio are handled. These and any other phenomena from borehole observations can have variograms calculated and stratigraphically constrained estimations made in a least biased geostatistical manner, in advance of the tunnel. RQD, or a prediction of rock fractures, is handled by the faulting and folding modelling facilities. This is probably the more interesting issue to pursue, as the fractal nature from small scale fractures and joints, to large-scale faults, can now be characterised more convincingly.

Mar 8, 2011

By Craw D

Quaternary warping and uplift of antiformal schist ranges in Central Otago, New Zealand, has resulted in recycling of alluvial gold from widespread, generally weakly auriferous, Miocene fluvial gravels that unconformably overlie the schist, into aprons of fan sediments along the range margins. Basement erosion during uplift has been limited and so gold input from sparse gold-bearing quartz veins in the schist has been relatively minor. In an eluvial cycle on the slopes of the ranges, chemical remobilization of gold occurs during oxidation and erosion of the Miocene sediments. The typically fine-grained (300-400¦m) gold undergoes chemical modification and grain size enhancement of up to two orders of magnitude, and much of it is redeposited in a large number of relatively small alluvial fans along the range margins. Groundwater mobility within the fans results in minor additional gold mobility and grain size Enhancement.

Jan 1, 1995

By McDougall I, Claoue-Long J

A combination of high precision 40Ar/39Ar and U-Pb dating has been used to determine the age of hydrothermal minerals and host rocks in a number of Lachlan Fold Belt (LFB) gold deposits in New South Wales, Au4 ralii In particular, this investigation demonstrates that the UAr/ Ar technique of K-Ar dating can be used to determine the timing of mineralization in Palaeozoic systems.A close temporal link between mineralization and Late Ordovician to Early Silurian magmatism is indicated by the dating work. Hydrothermal sericite from the Goonumbla p8rph gy Cu deposit and Glendale Au prospect yieldsAt/ Ar step heating ages between 437.9 ¦ 1.1 and 441.2 ¦ 1.1 Ma (16), and4 minjrnum age of about 425 Ma has been obtained by Ar/ Ar dating of hydrothermal amphibole from the Browns Creek Au-Cu skarn deposit. Hydrothermal aluniI8 frog the Gidginbung epithermal Au deposit yields reset 44 Ar/ Ar ages of 401.0 ¦ 1.3 to 417.3 ¦ 1.3 Ma (16). U-Pb dating by ion microprobe on magmatic zircons from the vicinity of the Goonumbla and Gidginbung deposits gives ages of 438 ¦ 3.5 Ma (2 6), and 435 ¦ 2.5 Ma (2 (7) respectimly, W a minimum age of 435 Ma has been obtained by Ar/ Ar dating of magmatic phases from volcanic rocks adjacent to the Browns Creek skarn deposit. Magmatic episodes near the Sheahan-Grants gold skarnpost give ages of 479.2 ¦ 1.1 and 467.9 ¦ 4o1 by 'Ar/ 9Ar dating of magmatic amphibole. Most Ar/3yAr age spectra show the effects of partial Ar loss at between 360-420 Ma, probably due to heating caused by granitoid emplacement.The radiometric dating work in this paper suggests a restricted metallogenic epoch in the Late Ordovician-Early Silurian LFB, NSW, of similar duration to that found in the Andean margin and the western Pacific island arcs around the Pacific Rini.

Jan 1, 1990

By K P. Crameri

The Beta Hunt orebody is situated on the south western limb of the Kambalda dome. It is one of the nickel occurrences in the area which fall into the category of æKambalda Style OrebodiesÆ. These orebodies are renowned as being continuous uniformly mineralised ribbons of nickel sulfide mineralisation. Interestingly, Beta Hunt does not conform to this notion of continuity and uniformity and is in fact highly irregular in its ore distribution due largely to the influence of post depositional structure. In an attempt to understand the ore distribution at delineation stage rather than development stage a detailed footwall topography model is created using all available drilling data. To augment this drilling data, the routine use of downhole EM and borehole radar has been introduced to provide data beyond the confines of the drill core to enhance the geological interpretation of the footwall topography and the distribution of the mineralisation. The implementation of a detailed footwall model and the use of downhole geophysics has proved to be very effective in resolving the orebody complexity issues. Ongoing development of the methods used will continue to refine the interpretation of the geology to enable more efficient extraction of the orebody.

Jan 1, 2006