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By Flann R. C

A small modification to current industrial practice should lead to better nickel powders for use in alloying, electroplating, and powder metallurgy. Nickel powder compacts sold for alloying are not always suitable for electroplating applications, since some presently used commercial powders will expand on sintering. Further, such nickel powders are unsuitable for use in the production of powder metal parts, because of expansion during heating of the near-net-shape preforms. Research in these laboratories has enabled the elimination of expansion, and led to techniques for the production of compacts suitable, in particular, for commercial use in both alloying and electroplating. The techniques include: powder pretreatment, cold pressing and sintering, hot pressing, and hot pressing and sintering. In this way compacts are readily prepared with densities of at least 93 per cent of solid nickel, and these, when used as anodes in Watts general purpose and bright baths, give both cathode current and plating efficiencies of 90-98 per cent.

Jan 1, 1979

By Horowitz F. G, Lamb P

As mining operations become larger and more complex, larger volumes of geological, geophysical, and production data must be manipulated and interpreted on a day-to-day basis. Because of the large volume of data, more sophisticated data storage strategies, interpretation tools, and visualisation tools must be used by exploration and mining operations in order to remain competitive. Critical to better practice is an understanding of the basic syntax and character of geological and mining data, expressed in the form of a data model. In the short-term, a data model can be used to implement or evaluate schemes for data storage or exchange. It can be used to evaluate software. In the longer term, a data model is essential to the design of the next generation of software for 3D geological modelling. In this and the related paper (Lin et al, 1995) the data model in use by CSIRO is presented, together with: 1. examples of the use of data transfer in the linkage of existing mining software; and 2. examples of the use of the data model in software design.

Jan 1, 1995

The treatment plant of the Gold Mines of Kalgoorlie Ltd. is situated on the Oroya South Lease, on the Eastern edge of the Kalgoorlie Golden Mile.It was designed and erected by Messrs. Alex. Stewart and Company, in consultation with Mr. Harry Hey, and was completed in November, 1937.Its original capacity was 9,000 tons of all-sulphide ore per calendar month, l?ut the plant was extended in October, 1939, to treat 13,000 to 14,000 tons per month of mixed sulphide and oxidised ore.Recovery of the gold is accomplished by cyanide treatment, followed by flotation of the cyanided residue, roasting and cyanidation of flotation concentrate and precipitation of the gold from the cyanide solutions. In the cyanide section, the crushed ore is finely ground in cyanide ,solution and the pulp is agitated to dissolve further gold. It is then thickened and filtered. In the flotation section, this filter residue is conditioned with S02 gas and a pyrite-gold concentrate recovered by flotation.This concentrate is roasted and then cyanided.KALGOORLIE ORE DEPOSIT.The Kalgoorlie ore deposit occurs within a wide area of Pre-Cambrian rocks, ,and consists essentially of two series of basic igneous rocks known as the older greenstone series (calc schist) and the younger greenstone series (quartzdolerite- greenstone) . The older greenstone is a group of lava flows. The younger intrusive greenstone series can, in the main, be classified as a chloritised and carbonated...

Jan 1, 1948

By F Clark, B Catto

The Mako domain comprises the Mako lodes at Sunrise Dam Gold Mine, Western Australia. This domain was initially bulk or æbucketÆ domained for the open pit resource in 2000, due to complexity in defining the lodes as a result of low drill density. Negative ore tonnage and positive grade and ounce reconciliations were experienced during mining of the domain in the mega-pit, though only small volumes of the domain were mined. Significant amounts of exploration and underground grade control drilling has been completed since the initial bulk domain interpretation and greater geological understanding of the mineralisation controls and geology of the lodes now exists. Mako provides approximately 50 per cent of the ore tonnes and ounces for the North Wall Cut-back, the latest open pit phase of mining at Sunrise Dam. The importance of Mako to mill supply and life-of-mine planning, as well as past reconciliation performance necessitated a reinterpretation of the domain to increase confidence for mining. Historic exploration drilling, underground grade control drilling and detailed pit-wall mapping were used to build mineralised subdomains within the confines of the original domain. These reflect more closely the spatial extents and geological controls on the mineralisation. A new resource model using the multiple indicator kriging (MIK) technique was generated using the new domains. It resulted in a decrease in tonnes and ounces but increase in grade for the sum total of the new domains compared to the old æbucketÆ domain. This is attributed to the increased selectivity and structural constraints imposed by the new domains. A retrospective comparison of the Mako grade control from the mega-pit versus the new resource model was conducted, which æreconciledÆ 103 per cent tonnes, 106 per cent grade and 110 per cent ounces. This has provided confidence that the new model is a better estimate of the lodes. Qualitatively, the new model is a better representation of the geology and extent of the mineralised structures with significant areas of change identifiable. Grade-tonnage plots comparing the 2006 and 2008 models show that most tonnes have been shed from the low-grade û subeconomic grade cut-offs. This is mostly attributable to the volume reduction of æoreÆ in the 2008 model compared to the 2006 model, where the true mineralised zones are captured by the new domains. The reinterpretation and remodelling of Mako is an example of an evolved domain model and shows that mineralised zones need to be differentiated adhering to the geology and geological controls on mineralisation, which are understood largely due to increased drilling density coupled with mapping.

Jan 1, 2009

The New England Fold Belt forms the easternmost and youngest section of the Tasman Fold Belt System of eastern Australia. From middle Palaeozoic to Early Cretaceous time it was the site of extensive episodic calc-alkaline magmatism related to W-dipping subduction. The oldest rocks may have formed at least partly in a volcanic island arc, but from the Late Devonian, the fold belt developed as a convergent Pacific-type continental margin. For Late Devonian-Carboniferous time, parallel belts representing continental margin volcanic arc, forearc basin and subduction complex assemblages can be recognised. Major dextral transform faulting may have offset parts of the fold belt in the Late Carboniferous. In addition, some structural blocks which appear to be out of place in the overall palaeogeographic setting are possible exotic or suspect terranes. A great variety of lode deposits ranging in age from middle Palaeozoic to Early Cretaceous is present in the New England Fold Belt. The vast majority of these are related to emplacement of extensive granite plutons and eruption of continental silicic volcanics in Late Permian-Late Triassic time. However, volcanogenic massive sulphides and volcanic hosted epithermal gold-silver deposits in older rock sequences include one major orebody (Mount Morgan) and several important ones (Mount Chalmers, Cracow, Silver Spur, Cangai and Halls Peak). Some problematical deposits are best classified as metamorphic-hydrothermal. These include gold-bearing quartz reefs and stockworks in sedimentary host rocks, the most important of which are at Gympie, and antimony-gold- tungsten mineralisation in the New England area, mainly at Hillgrove.

Jan 1, 1987

By Watson DF

Calculation of the amount of metal in an ore deposit or mining block should be approached by multiplication and integration of appropriate numerical manifolds describing the spatial distribution of the relevant variables, viz. grade, specific gravity and also thickness for bivariate data. Construction of a numerical manifold necessarily involves some form of interpolation but detailed characteristics of this are often not specified in various automatic methods, some of which even provide manifolds with discontinuities. A manifold used in calculations should describe in a geologically plausible way the spatial distribution of the variable of interest. Different approaches to the problem are discussed and compared. Particular computational inconsistencies emerge when "accumulation" is used as a variable in calculations of average grade. If an ore deposit is variable in relation to its sampling and especially if selection of mining blocks according to grade cut-off is a necessary operational decision, the biases introduced by accumulation methods can bring about serious problems of over-evaluation. Modern computational techniques make unnecessary the use of accumulations; because of potential inconsistencies it would seem unwise to use them in any ore reserve computation.

Jan 1, 1987

Comparison of the Zadra, Anglo-American and organic solvent procedures for desorption of gold from activated carbon loaded in carbon-in-pulp gold circuits indicates that the Anglo American and the organic solvent procedures are considerably more effective than the commonly used Zadra procedure. Organic solvent elution procedures, particularly those using acetonitrile and acetone, can provide effective gold elution and very high concentrations of gold in eluate solutions. The operational simplicity and effectiveness of the Anglo American procedure would appear to make it the most satisfactory procedure available at the present time but this may change as the solvent elution procedures become better developed. INTRODUCTION The carbon-in-pulp technique has been introduced into the gold processing industry to by-pass the often lengthy CCD and filtration steps required in the conventional Merrill Crowe cyanidation procedure for gold recovery. Adsorption of gold on to carbon is also a valuable technique for recovering trace amounts of gold from low level waste streams from conventional processing procedures.

Jan 1, 1982

Coal is of tremendous importance for the Czechoslovak econ- omy. The current annual primary energy demand being about 109 million tons of standard fuel (1 ton of standard fuel - 7,000 coal = 29,308 GJ), coal satisfies almost two thirds of our fuel consumption. If compared with the distribution of resources in the world's fuel and energy pattern, the situation in Czechos- lovakia is significantly different, as shown in Fig. I. One of the causes behind the difference is that the Czechoslo- vak oil and natural gas reserves and, hence, their production are insignificant, so that it is necessary to import them. Brown coal will continue to play an important role as a prin- cipal domestic source of primary energy even in the future. While the share of nuclear power is increasing, brown coal represents strategic reserves in the fuel and energy balance.

Jan 1, 1989

By M D. Basuki Dwi Priyono

The Toguraci low sulfidation epithermal gold vein deposits are located 2 km WSW from the Gosowong mine and form part of the Gosowong Goldfield. The goldfield lies within a Neogene magmatic arc on Halmahera Island, North Maluku Province, East Indonesia. The terrain is moderate to steep, rainforested, and poorly outcropping. Exploration and mining operations are being carried out within the PT Nusa Halmahera Minerals Contract of Work (exploration tenement) jointly owned by Newcrest Mining Ltd (82.5 per cent, operator) and PT Aneka Tambang Tbk. (17.5 per cent). First pass exploration of the Gosowong area began late 1992 resulting in the discovery of weakly developed porphyry copper mineralisation (named Bora) at Toguraci in 1993. Early in the evaluation of this porphyry an overprinting epithermal Au/Ag mineralisation event was recognised, however exploration focus remained on the Bora porphyry deposit for some time. The discovery of the nearby Gosowong epithermal gold deposit and the exploration of other prospects in the area further diverted attention and funds from Toguraci. It was not until year 2000 that Toguraci was seriously reevaluated as part of a detailed appraisal of the epithermal gold potential within a 5 km radius of the Gosowong gold mine. A fly-camp based drilling campaign using man-portable rigs was undertaken between August 2000 and March 2002. All exploration at Toguraci was then stopped pending government approvals to mine. These were finally issued in May 2003 and immediately drilling restarted and pre-mine approvals (eg the environmental impact study) were sought and granted. The first Toguraci gold bar was poured in February 2004. Exploration at Toguraci and elsewhere in the Gosowong Goldfield continues today.

Jan 1, 2004

The discovery of economic uranium miner alisation in unique geological conditions at Yeelirrie, 700 km NNE of Perth, presented Western Mining Corporation Limited with a num- ber of sampling and evaluation problems. Carn- otite mineralisation occurred in a porous cal- crete-clay lithology in close proximity to the water table; background information on such a deposit was non-existent and sampling in these conditions could be difficult. The deposit was sampled initially by aug- er drilling with X-ray fluorescence analysis of drill cuttings, followed by reverse circulation and diamond drilling with analyses by X-ray fluorescence and gamma logging of the holes. Two costeans provided lithological and grade distribution data and mining experience in the deposit. Spoil from the costeans was stockpiled according to location in the first costean and according to location and grade in the second costean. Samples from the various stockpiles were analysed by X-ray fluorescence. No. 1 costean was extensively sampled by channel sampling of the walls and by pit sampling of the floor of the benches of the costean by back hoe. No. 2 costean was sampled by Geiger counters mounted in T-probes and by the gamma logging of auger holes to establish the valid- ity of the T-probe results. Samples were taken

Jan 1, 1976

The paper describes a computer model developed within the State Electricity Commis- sion of Victoria for use in open cut planning. The purpose of the model is to simulate all the typical occurrences in, and influences on, the coal supply and overburden disposal systems in order to be able to assess their performance. The model incorporates much of the long term and day-to-day operations planning logic required for the allocation of resources within an open cut. This logic takes account of power station demands, bunker stocks, plant and crew availability, the balance of reserves between dredgers, planned maintenance, etc. The perfor- mance of plant within the system is simulated using random selections from statistical distri- butions of Time to Failure and Time of Failure for each plant item. The application of the model in selecting a suitable bunker capacity in a notional open cut development is described to illustrate the potential of the model in optimising plant selection.

Jan 1, 1982

Discovered in 1954 and mined since 1966, the X41 copper orebodies have produced over 143 Mt @ 3.3 per cent copper. By June 2002 the production from these orebodies had depleted the Mineral Resource to 36.6 Mt @ 2.8 per cent Cu (including 31.5 Mt @ 2.5 per cent Cu combined 2002 Ore Reserve). Mine production will ramp down to cessation beyond ten years. The 2002 Copper Business Study was commissioned to review the status of the Mount Isa copper business and to optimise the long-term strategy of the operations. The study resulted in a vastly improved geological and geostatistical model, and financial studies led to the optimisation of mine cut-off grades. Utilising these new models, a near-mine target generation workshop was conducted by the copper stream geology team. The workshop focussed on exploration for new ore sources and the extension of existing orebodies to supplement the Mineral Resource inventory for future conversion to Ore Reserves. Several prospective targets were identified and the Conceptual Northern 1100 Drilling program was subsequently designed. This paper shall discuss the practicalities of near-mine target generation in Mount Isa, the issues faced when locating and preparing drill sites in a mature mine environment, and the preliminary results of the drilling program so far.

Jan 1, 2003

By Armstrong ME

The gas bubble energy generated by an explosive plays a major part. in the fragmentation, muckpile movement and damage produced. Previously, the interaction between gas pressure and the rock has been interpreted from a theoretical basis or a qualitative study of breakage mechanisms. A method to measure the fluctuations in gas pressure in rock adjacent to the blast has been developed. This peak pressure will vary with structure, as well as with distance and explosive type. The technique is simple to apply and can be used to observe the flow rate of gas at. varying distances. The apparent velocity of penetration is an indication of whether gas has travelled through pre-existing or blast induced cracks. The technique provides a ?n:eans of determining the suitability of an explosive for a given rock type, depending on the amount of displacement desired. The technique has application in optimir.irig throw blasting and predicting and controlling damage, particularly in highly structured rock masses.

Jan 1, 1986

Mining is taking place at increasing depths of cover on the Southern Coalfield beneath pre- dominantly massive sandstone strata. Within the next twenty years, there will be longwall mining at depths greater than 600 m. As the Sydney Metropolitan area continues to expand and as coal mining approaches these urban areas subsidence will continue to become an increas- ingly important aspect of coal mining research. Investigations commenced in the mid 1960's and it is now possible to predict subsidence in the Southern Coalfield with reasonable con- fidence. The work is showing that the characteristics of the subsidence troughs over the deeper mining at Appin differ from the characteristics of mine subsidence at less cover. The longwall mining at Appin Colliery has resulted in a maximum measured subsidence of 730 mm. The maximum strains were small because of the large radii of curvature of the subsidence profiles. There was no damage to any of the buildings in the township of Appin.

Jan 1, 1981

Techniques and results achieved during the excavation of the Melbourne Underground Rail Loop (HURL) are summarised and discussed in the context of the various restraints present in a typical urban construction project. Mechanical methods (as distinct from those utilising blasting)accounted for the bulk of the excavation. Ground support was critical in this particular geological excavation setting, but is not discussed in detail except insofar as it constitutes a restraint to excavation progress.

Jan 1, 1978

By R Smart

This paper examines the longer-term predictive capacity of the GAMSPATH computer program (developed by the Alberta Research Council) for a waste rock (sample MS) obtained from the Kaltim Prima Coal (KPC) mine, Kalimantan that contained significant framboidal pyrite. The model was refined by comparison with the net acid generation (NAG) and column leach tests to provide a basis for calibration of the model for both short term and longer-term reaction trends. The oxidation of pyrite during the kinetic NAG test using H2O2 provides oxygen directly at the mineral surface, generating a measured oxidation rate for pyrite of 1.16 + 10-6 mol m-2 s-1, whereas the oxygen diffusion limited rate in the leach column air equilibrated reaction was of the order 10-8 mol m-2 s-1 as calculated from the GAMSPATH thermodynamic database. Results indicated that the oxygen derived from hydrogen peroxide had to be included as a reactant (eg a reacting mineral) in the simulation to account for the direct availability of oxygen at the sulfide mineral surfaces. Optical investigations identified the proportion, particle size, and surface area, of framboidal and euhedral pyrite in sample MS. The reactive surface areas of the two morphologies were very different (eg ratio: 5:1). To manage these two different pyrite morphologies the GAMSPATH thermodynamic database was updated to include framboidal pyrite, with similar thermodynamic properties and oxidation rate to euhedral pyrite but with a particle size based on the size of the individual internal framboid microcrysts. This modification, with framboidal pyrite reaction based on the size of its microcrysts produced results that correlated well with the kinetic NAG and column leach test results when the measured (kinetic NAG test rate) and calculated (column test rate) pyrite oxidation rates were employed. This provided some confidence that the model could be extrapolated to indicate longer-term geochemical reaction trends.

Jan 1, 2003

Future hard rock mining will gradually move towards complete mechanisation which lends itself to remote control and ultimately to robotic mining. This will require different technical inputs into mining engineering and one of these is in the area of rock'mechanics. Traditional hard rock mining has had little rock mechanics input. Problems arising from high stresses and poor ground conditions have in most cases be remedied after they occurred, in the worst case by abandoning a particular stope or area and starting elsewhere. In a fully mechanised remote or robotic mining situation the financial penalty for such an approach could be severe, as a major part of the production costs will be in the development and the equipment. It is therefore imperative that a complete rock mechanics feasibility study is undertaken before an area is set up for robot mining and that a continuous stability monitoring system is installed that will predict rock behaviour well in advance of mining, such that the necessary ground control measures can be implemented without impeding the continuity of mining. This system will utilise already existing instrumentation such as extensometers and stress cells, and possibly additional improved instrumentation which has to be developed for this particular Application.

Jan 1, 1986

By Clappison D. J

Since its formation in Papua New Guinea and raising of A$2 million in 1980, Niugini Mining Limited (NML) has grown to a company capitalised on the Australian Stock Exchange at about A$350 million. In 1995 the company produced some 237 000 ounces of gold, 700 000 ounces of silver and nearly 5000 tonnes of copper from its operations at Red Dome, in North Queensland and San Cristobal in The Atacama Desert of Northern Chile. This production contrasts with Niugini Mining's first mining venture at Mt Victor in the Eastern Highlands of PNG which yielded 20 000 ounces of gold and 11 600 of silver between 1987 and 1989. Following the formation of an exploration joint venture in 1982 with Kennecott Explorations (Australia) Ltd, now a subsidiary of RTZ, Niugini Mining's early recognition of the gold potential of volcanic rocks at plate margins led to discovery of the Lihir deposit in July 1982. This deposit containing about 42 million ounces of gold in resources, is one of the largest undeveloped gold deposits in the world. Following raising of equity funds through the float of Lihir Gold Ltd and debt finance in 1995, construction of the mine at a cost of US$673 million is now underway with first full-scale production at approximately 600 000 ounces of gold per year expected in early- 1998.

Jan 1, 1996

By White A. H, Vihena M. T M B

Presently, orebody modelling consists basically of fitting a mathematical model to represent spatially a certain geological variable, generally grade. An orebody model is constructed from a set of sample data obtained from various locations in the orebody, thus it is only one form of representation of the true phenomena. Checking the compatibility of the data with the modelling procedure is the most important factor when assessing confidence in the orebody model. The level of confidence in the model will depend on the adequacy of the data set and the validity of the basic assumption required by the modelling method. Fractal geometry is one way of modelling the spatial distribution of a geological variable in an orebody geometry. Fractals can be used to interpolate the Z(x) geological variable at unsampled sites. The concepts of self similarity and self affinity that form the basic assumption of fractal geometry theory which areinvestigated. The population distribution of the geological variable in question must be examined to determine the appropriateness of both fractal geometry and geostatistical modelling methods. The selection of the most appropriate method depends on the available data. A researcher or a practitioner needs to understand the strengths and limitations of the various modelling methods before choosing the most appropriate method. This study investigates the fractal properties of grade distribution using the variogram and some proposed variations as techniques to measure the fractalness. The aim is to assess applicability of fractal geometry theory to modelling ore grade distribution in a deposit. A comparison of the results demonstrates the methods which better capture the spatial behaviour of the variable under study.

Jan 1, 1995

By Lewis W. H, Leigh M. C, Mayercheck W. D

The U. S. Department of Interior's Bureau of Mines, in conjunction with a cooperator in the U. S. A., are developing a new highwall mining system (HMS) for coal extraction in unreclaimed and active contour strip mines. This prototype system is comprised of a computer-based remote control (CBRC) system to monitor and remotely control a thin-seam continuous miner (TSCM) and a 76*m long multiple-unit continuous haulage (MUCH) conveying system, plus other manually- operated support equipment located on the highwall bench. The TSCM and MUCH coal haulage system are both controlled remotely by a single operator in a protective enclosure at an ergonomically- designed workstation located on the highwall bench. Two other personnel work on the bench to operate other support equipment. Full-scale mock-up fabrications were employed in the design of the unique remote control operator workstation. The HMS should allow the safe and economical exploitation of increased coal reserves where they outcrop in hilly regions of the United States. It should also be competitive with conventional auger mining and other coal extraction techniques, with a productivity goal at a highwall site of 20 tonne/man-h. Extensive simulated surface tests of the miner and haulage system should be completed in early 1988 at Bureau test facilities at Pittsburgh, Pennsylvania. These will be followed by actual coal production trials of the entire system in 1988 at a highwall site in West Virginia/USA.

Jan 1, 1988