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By Roddick F

From its mining lease at the northern end of Cohens Reef at Walhalla in the North Gipps- land mountains, the Long Tunnel Extended Gold Mining Company produced 13,695kg of gold, which at 1982 prices represents a value of about $140 million. In the period 1885 to 1908 the mine was one of Australia's principal reef gold producers, being top Victorian producer in six of these twenty-four years. Prior and subse- quent occupants of the lease produced an addit- ional 160kg of gold. The Extended and the other mines on Cohens Reef whilst contributing importantly to the financial resource of Victoria, were the sole important support for the substantial town of Walhalla that had grown up around them. When the mines closed, Walhalla gradually reduced from a bustling developed town to the present attractive mountain village so favoured by tourists.

Jan 1, 1982

By Marquez W

Trace fossils have been found in Bolivian Silurian sediments in "La Iumhre" area close to La Paz-Bolivia.Tracks, are good indicators of depth and environment. A detailed study of the ichnogenus is made.The depth and environmental deposits are analyzed to determine the facies. It was shown that the trace fossils of Silurian sediments in La Paz belong to the Zoophvcos and Nereites facies.

Jan 1, 1990

By Christie AB, Bull VH

The geological environments of gold deposits are reviewed in relation to the strong resurgence in exploration for gold since 1979. The resurgence is due mainly to New Zealand's geological endowment with gold and its history as a gold producer. Major past production was from Cenozoic placers of Otago and Westland, late Cenozoic epithermal deposits of the Hauraki Goldfield, and the respective Paleozoic and Mesozoic lode deposits of the Reefton and Otago Goldfields. These same geological environments are the targets of current exploration, mainly in extensions of previously mined deposits. On the Westland and Otago Goldfields alluvial and fluvioglacial gravel placers, mainly representing lateral and depth extensions of previously worked ground, are being mined and prospected. Gold production in 1984 was exclusively from these deposits, and the development of mobile concentration plants has resulted in a great increase in mining activity. Mineralised zones adjacent to previously mined lodes in the Hauraki Goldfield, Reefton Goldfield, and at Macraes Flat (Otago Goldfield) are being intensively explored. At Waihi (Hauraki), an open-pittable resource of about 10 million tonnes of ore has recently been delineated. Some new deposit types and little explored environments are also receiving attention. They include: gold-sulphide quartz veins hosted in an alkaline granite dike in west Nelson; hot spring type gold deposits in fossil geothermal (epithermal) systems of Northland, the Hauraki Goldfield and the Taupo Volcanic Zone; and marine placers off the West Coast where an area of auriferous gravels has been outlined near Hokitika. There is potential in known deposits and prospects currently being evaluated for a large increase in gold production by the early 1990s.

Jan 1, 1986

By Spencer P. A

Bacterial oxidation, previously known as bacterial leaching or bio-leaching, has been applied at laboratory and pilot plant scale to many refractory ores and concentrates around the world. The most common bacterial culture used in this process has been Thiobacillus sp. This organism is limited in commercial application, especially in Australia for several reasons. The optimum operating temperature range for this culture is 30¦C to 40¦C and high levels of some metals such as arsenic, silver, and copper have toxic effects on the culture thus reducing its effectiveness. The culture employed by BacTech (Australia) Pty lid is a moderately thermophilic culture which operates in a temperature range of 40¦C to 55¦C (which is more amenable to the Australian climate) and with higher resistance levels to metals often found to be toxic to Thiobacillus sp..

Jan 1, 1991

High sulphur volcanic-hosted hydrothermal environments are favourable geological environments for gold mineralisation. Numerous world-class gold deposits including Pueblo Viejo (Dominican Republic), Goldfield (Nevada), EI Indio (Chile), and Wa

Jan 1, 1994

By Osborn G

The bulk flotation behaviour of an industrial rougher bank has been determined with a view to characterising the size iepend ent behaviour of the identifiable nineral groups present. A relatively simple flotation model, based on first order kinetics and the assumption of perfect mixers in series ias been used to provide a fit to the operation of the cells. The adequacy of the model is discussed in relation to the characteristics of the ore and the size iependancy of the parameters. It is shown that improved fits are possible if the model accounts explicitly for this size dependancy and demonstrated how the model may be of use in prediction of the grade recovery relationships for different operating conditions as an aid to plant optimisation.

Jan 1, 1986

By Delahey G, Dunne R

At New Celebration Gold Mine the advent of treating primary sulphide ores resulted in decreased gold recoveries of four to ten per cent. The grind coarsened due to an increase in ore hardness and gold in the residue was found to be associated with pyrite. Finer grinding improved recoveries but was impractical as production rates would have decreased to unacceptable levels. An alternative approach that has proved to be viable combines both gravity separation, to recover the coarse gold bearing sulphides, and then regrinding the concentrate in a tower mill prior to releaching in the cyanide leach circuit. The tailings treatment plant was commissioned in December 1990 and details of the first 18 months' operations are Provided.

Jan 1, 1993

The Golden Plateau Mine is located at Cracow in central Queensland, 350 kilometres north west of Brisbane. The mine was operated by Golden Plateau NL as an underground mine from 1933 to 1976 with a total production of 18.5 tonnes of gold. Prod

Jan 1, 1994

By S Maryati

Surface mining activities disturb large areas, produce great sediment loads and tend to be a source of water pollution if they are not managed properly. Coal mining in Indonesia has a very high risk of soil erosion because the coal mining areas are generally located in tropical areas with a high average of rainfall (4000 - 6000 mm/year) and use surface mining methods. The main factors affecting erosion risk are climate, soil type, topography, vegetation cover and management factors. Thus, the monitoring of erosion risk in mining areas is very important due to the characteristics of coal mining in Indonesia. The objective of this research is to determine the ability of satellite images (remote sensing data) and geographic information systems (GIS) to provide an accurate and up to date spatial database for the monitoring of erosion risk in surface coal mining areas using the Universal Soil Loss Equation (USLE) method.The erosion risk analysis and spatial data processing are generated by the ArcGIS 9.3 software and need several data, namely: an erosivity map, erodibility map, a slope map, vegetation index map and land management or land cover map. The erosivity map is derived from the rainfall data, whereas the erodibility map is derived from the soil map. The slope map is derived from the SRTM-DEM (Shuttle Radar Topography Mission-Digital Elevation Model) and processed using 3D analyst tools. Furthermore, the vegetation index map and land cover map are derived from a satellite image using digital image processing techniques.This preliminary study produced results that show soil erosion monitoring, which is integrated with remote sensing and GIS technologies, has great potential for producing accurate, advance, and low cost erosion risk maps in coal mining areas. This map is very important for getting spatial distributions of the erosion and useful for developing erosion management plans.

Nov 22, 2011

It is no longer adequate in running mines and quarries to simply select the best equipment. Today's competitive international commodity markets demand superior efficiency. This requires efficient production and commercial processes together with systematic involvement of people in continuous improvement of processes. True Total Quality of Management (True TQM) principles provide an operating philosophy for maximising productivity and minimising unit costs of output. Unfortunately, even though these principles are proven in all industry sectors worldwide, they have not always been used correctly. This paper describes basic methodology for correct use of these principles to successfully improve the productivity of rock breakage production processes.

Jan 1, 1995

Three key areas of C.I.P. plant design, viz. leach- ing time, adsorption and the gold loading on the carbon, are discussed and illustrated with examples. The need for accurate pilot plant data for use in assessing and optimising design is emphasized. This approach should minimize capital and maximise return on capital. It is demonstrated that, as regards adsorption, economics favours short retention time, high gold loadings and mechanically agitated, draft tube reactors. INTRODUCTION Little attempt appears to have been made in Australia to design the present generation of C.I.P. plants to achieve an economic optimum. Most would, seem to have been based on pre- liminary leaching data, gold extraction and value and rule of thumb which, in general, has led to over design and over capitalisation. An essential step to effective economic design is a comprehensive pilot plant study to establish definitive operating parameters, yields and reagent costs. In most cases the cost of developing this data will be more than offset against capital savings in plant; the operating profit should be increased substantially, and profit is maximised for known

Jan 1, 1982

Mining software packages are used extensively in industry for resource estimation as well as for mine design and operation. Research undertaken in the W H Bryan Mining Geology Research Unit at the University of Queensland has shown that modifi

Jan 1, 1994

By Penttila V

The Paleoproterozoic Hitura Ni-Cu deposit in western Finland is in an ultramafic igneous complex composed of two subvertical plug-shaped bodies embedded in intensely migmatised felsic gneisses. The ultramafic complex is not far from a north-south trending graphitic and sulphidic gneiss zone interpreted to be a primary sulphide-graphite unit in the metasedimentary sequence. The sulphide accumulation exists as a zone parallel to the contact of the northern ultramafic body. The ultramafic rock types, now mainly serpentinites, have primarily been olivine adcumulates in the core grading to olivine orthocumulates and pyroxenites towards the margins. Coarse-grained felsic pegmatite veins injected serpentinite where they now exhibit prominent zoned alteration rims of chlorite, antophyllite and talc. The serpentinite core of the body was primarily an olivine adcumulate derived from a tholeiitic or high-Mg basalt parental magma with about 11 wt % MgO. Metamorphism and alteration have totally changed the igneous mineral compositions and the rock types are serpentinites (from olivine adcumulates), ambhibole-bearing serpentinites and amphibole-chlorite rocks (from pyroxenites). As the result of CO2 alteration talc is an accessory mineral throughout the serpentinite. Like silicates, also sulphide minerals are altered. In the core of the body the low-grade sulphide dissemination still reveals primary igneous interstitial forms. The core sulphides are now mackinawite, pentlandite and valleriite instead of primary igneous pyrrhotite and pentlandite derived from Mss. At the marginal zone the heavy dissemination and net-textured sulphides display pyrrhotite-pentlandite-magnetite intergrowths with magnetite films along cleavage of sulphides, mackinawite in pentlandite and exsolution textures of different low-temperature pyrrhotite phases as the result of alteration processes. Mechanically weak rocks, complicated structures and textures of the ore, magnetite and mackinawite intergrowths in pentlandite and readily-floating MgO silicates cause problems in exploitation of the deposit. Solution to problems come from selective stoping, three-step classification in grinding, froth-washing technique and on-line process control based on ore type determination from process data using an expert System

Jan 1, 1996

By G Byrne

Long-term water management is typically ignored in mine closure planning. A review of 73 mine closure plans dating from 2007 to 2013 shows that, on average, relinquishment is proposed to be achieved in 11 years. A separate review of 57 mines in actual closure shows that only five have so far achieved relinquishment with an average closure period of 14 years after production cessation. The remaining 91 per cent of sites in closure have an average closure duration to date of 21 years - and still going.A common issue among those sites in closure is water management, with a further common issue being acid and metaliferous drainage (AMD). Of the closure plans that were reviewed only one site had allowance for long-term (>50 years) of water treatment. Of the sites in actual closure 25 per cent have reported that they expect such long-term water treatment, with many acknowledging that in perpetuity treatment is probable.Clearly there is a gap between what is being allowed in closure plans and the reality of closure. There are a number of factors leading to the optimism of the closure plans, including unrealistic assumptions, pressures to reduce closure cost provisions and the technical complexity of many AMD issues.Long-term water management is a reality that needs to be acknowledged and addressed. If addressed early in the mine life cycle the impacts for mining companies can be reduced.CITATION:Byrne, G, 2013. Long-term water management - the forgotten legacy of mine closure, in Proceedings Water in Mining 2013 , pp 163-168 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

Land is of extreme importance to citizens of Papua New Guinea and is fundamental to most of their customs and values. Because of this, matters to do with land cannot easily be separated from other matters to do with the community. Good relation-ships with landowners and the community surrounding a development are, indispensable ingredients that -must flavour and colour the entire ;operati on .

Jan 1, 1994

DURING the four years, 1922, 1923, 1924, and 1925, China produced the following quantities of non-ferrous metals and ores: Antimony Products - 67,869 (long) tons. The production for 1925 was 20,869 tons, of which 80% was regulus, 14% crude,and 6% oxide.Arsenic (White) - 4200 tons. The production for 1925 was 1200 tons, but only 90 tons were exported, some 25% of which to Hong-Kong, France, and U.S.A. each, and the rest in small lots to other countries. Domestic consumption was 1110 tons, and thelocal price for "cake" was around £47 per ton on 1925 exchange.Arsenic Ore (Realgar) - 1400 tons.Lead Ore (Galena) - 44,853 tons. The production for 1925 was 10,853 tons, of which 16%, produced in Korea, went to Japan, and 84% produced in Hunan, went to Europe.Manganese Ore (Pyrolusite) - 142,567 tons. The production for 1925 was 42,567 tons, of which 94.3% went to Japan.Tin Ingot - 33,480 tons. In 1925 the exports to Hong-Kong were 8880 tons of usual rough tin of 94% to 96%. Most of this was refined to No. I Chinese quality of 99.3% and exported to U.S.A. and Europe, owing to the good price ruling.Sulphur - 12,000 tons. Sulphur is included in this list in order to explain how its production led to the discovery of some other ores.Wolfram - 19,668 tons. The production in 1925 was 5868 tons, most of which came from the Quee Mee mountain district in South Kiangsi, from the detrital deposits. Civil disturbances prevented the usual output from Hunan border.Zinc Ore (Blende) - 134,190 tons. Exports for 1925 were 34,190 tons of low-grade ore, averaging 30% zinc, 14% lead, and 7% silver...

Jan 1, 1927

By Gregory L. M, Phillips G. N

Although it has long been recognised that there is a diversity of minerals associated with Victorian gold deposits, the degree to which this mineralogy is systematic or haphazard has remained uncertain. Recent work by the authors and students under their supervision permits a sharp delineation of the boundaries between different mineralogical domains, and these are interpreted in terms of recent rapid advances in Victorian tectonics, and the regional framework of Victorian gold geology described in Phillips and Hughes (1996).

Jan 1, 1997

Mount Isa Mines' Hilton Mine was brought into large-scale production in 1990/91 at a time of sharply falling metal prices. To ensure the operation's survival and eventual prosperity there was an urgent need to reduce operating costs and increase revenue. A target of a 40 per cent increase in productivity over five years was set. Strategies to obtain the required improvements were developed on the basis of greater involvement and increased contribution from the workforce, major changes to the mining methods and the development and application of new technology. This paper describes the organisational, operational and technological changes that have been implemented at Hilton and presents the results achieved to-date.

Jan 1, 1993

By Thornton D, Esterle J, La Rosa D

Control of blast fragmentation has a significant impact on coal mine profitability. Two approaches for the characterisation of coal blastability, particularly in terms of fines, are presented. Both approaches were implemented for the predictio

Jan 1, 1998

Quite often the reserve assessor becomes enamored with the numbers gen- erated and forgets the basis for his assessment. The quality of the assess- ment can only be as good as the quality of the input data. The use of seismic data from the Gippsland Basin in assess- ing Esso/BHP's oil and gas reserves is an excellent example of this principle. By significantly improving the quality of seismic data, a much more reliable estimate of a field's reserve potential can be made. In addition, it provides the basis for further delineation drill- ing which, as recent experience in Gippsland has shown, often leads to increased reserves.

Jan 1, 1979