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In the new refinery, at the works of the Broken Hill Associated Smelters Proprietary Limited, situated at Port Pirie, South Australia, the refining routine is similar to that carried on in the old one in that bullion is progressively refined first for arsenic and antimony, then for copper and gold, then for silver, and finally for zinc. However, actual procedure differs in that each refining operation is now conducted continuously, whereas in the old refinery intermittent batch treatment was practised.The early experimental work was concerned solely with the development of the continuous desilverising process, which, in addition to continuous treatment, embraces the novel feature of conjugate solution formation with consequent production of a silver product relatively high in silver and low in lead.

Jan 1, 1932

By K Orth

The volcanic successions that host massive sulphide deposits are diverse in composition, facies types and facies relationships. They also show a variety of spatial and temporal relationships to mineralisation. In many examples, such as the Koongie Park Formation in Western Australia, the host succession includes more or less conformable syn-volcanic sills with peperitic contacts. Such sills can be an important source of heat for fluid circulation, influencing patterns of hydrothermal alteration and the location of co-eval and later mineralisation. The impact of syn-volcanic sills on the host succession depends in part on the initial porosity and permeability of the enclosing facies. The special properties of glassy pumice û being highly porous, permeable, and reactive û allow pumice-rich facies to preferentially focus hydrothermal fluid flow. However, the same properties promote early alteration and porosity reduction. Hence, the diagenetic and compaction history of pumiceous facies strongly influences their potential to host massive sulphide mineralisation. In contrast to pumice, dense glass has relatively low porosity, at least initially, and does not compact. Non-vesicular glass is a major component of submarine lavas, syn-volcanic intrusions and some volcaniclastic facies. However, especially in submarine settings, dense glass is commonly intensely perlitically fractured soon after eruption. The fractures greatly increase the porosity and permeability, locally accelerating diagenetic and hydrothermal alteration. In addition to false pyroclastic textures, altered perlite may exhibit false porphyritic textures. Silica- or feldspar-altered perlite kernels surrounded by intensely altered phyllosilicate domains can resemble phenocrysts in a fine grained groundmass.

Jan 1, 1999

A new plant for grinding limestone was built at the Risdon Works of the Electrolytic Zinc Company of Australasia Limited to meet increasing process demands expected to reach 150 tonne/day of ground limestone. Plant specifications included open- circuit wet grinding, a single ball mill, a feed sizing of minus 6 Tyler mesh, a product sizing of 100 per cent minus 200 and 95 per cent minus 325 Tyler mesh and for the plant to be unmanned during normal running. Main features of plant and equipment are described; grinding performances given, as well as operating experience since commission- ing of the plant in March, 1976.

Jan 1, 1977

By A Hekmat, R Castro, A Casali, R Gómez

Block caving is the most economic underground methods for excavating massive orebodies, due to the high productivity and low production costs. The success of block caving operations depends on the fragmentation and draw control as large blocks decrease the equipment efficiency, inhibit the material flow and may lead to expensive secondary blasting. Even though ore handling system design, as well as overall economic results, both critically rely on secondary fragmentation, this parameter continues to be one of the least understood issues in the caving operations.This research focuses on the experimental study of secondary fragmentation, considering the impact of vertical pressures and material flow. Experiments using a load-haul-dump extraction system were conducted under laboratory conditions to quantify the influence of pressure and particle size on secondary fragmentation. Results demonstrate that increasing the vertical pressure (simulating deeper conditions) leads to higher fragmentation (smaller particle size) and greater fines generation during draw. The experimental results were applied to calibrate the developed mathematical model based on kinetic matrix. The acceptable accordance between the comminution model results and the reality showed that this method is convenient in predicting the secondary fragmentation in block caving.CITATION:Castro, R, Gómez, R, Casali, A and Hekmat, A, 2016. Experimental and comminution model framework for secondary fragmentation prediction in block caving, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 175–182 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By A B. Christie

In Northland, Coromandel, Taupo and Canterbury, weathering and hydrothermal alteration of Cenozoic volcanic rocks has resulted in the formation of various types of clay deposits. Subtropical weathering of rhyolite in the Matauri Bay area (Matauri and Mahimahi deposits) in Northland has formed high quality halloysite deposits. The Matauri Bay halloysite is mined and processed to produce reputedly æthe world's whitest clayÆ that commands a high price in niche ceramic markets. In the Coromandel, some argillic alteration zones contain kaolinite clays (at Hahei) and advanced argillic alteration zones contain kaolinite-gibbsite-pyrophyllite assemblages (at Pumpkin Hill and Lookout Rocks). In addition to known halloysite and kaolinite clay deposits, there is also economic potential for smectite clays produced by hydrothermal alteration of volcanic rocks. Bentonite (mainly ferriferous-beidellite) is mined from weathered basaltic ash in Miocene lake beds at Coalgate in Canterbury.   We have compiled interim mineral deposit profiles for bentonite in basaltic ash, halloysite in rhyolite, kaolinite in altered rhyolitic rocks, kaolinite-gibbsite-pyrophyllite clays in advanced argillic alteration zones and for smectite clays in argillic alteration zones. These deposit profiles include geological and mineralogical attributes, which are linked to the underlying volcanic, hydrothermal and weathering processes that have produced the clay minerals from their source volcanic rocks. Further work on refining the deposit profiles includes characterising the composition of selected deposits to determine spatial trends in mineralogy and geochemistry.

Jan 1, 2007

By M A. Vinokurova, V M. Mullov

Due to treatment of refractory carbonaceous low-grade gold ores a new technology providing improved precious metal recovery is required. For this reason, a technology including gravity, flotation, recleaning of the flotation concentrate, intensive cyanidation of the gravity concentrate and carbon in leach (CIL)-process for intensive cyanidation tailings and the recleaned concentrate was developed. The proposed technology allows to decrease preg-robbing activities of concentrates treated by subsequent cyanidation. Total gold recovery by the proposed technology from the ore with a head grade of 0.8 g/t was 83.9 per cent. The gold loading onto the activated carbon from CIL process was 6.500 g/t.

Jan 1, 2007

Inadequate understanding and/or assessment of technical and economic risk associated with geological uncertainty are key reasons many mining projects do not achieve forecast profitability. In the last 20 years many new and existing mines have experienced geology related problems, including lower than planned development and production rates, geotechnical/stability issues, unplanned dilution, ore loss, reduced metallurgical performance, environmental management concerns and unbudgeted capital/operating costs. Greater emphasis on the evaluation and communication of uncertainty associated with geological interpretations for feasibility and operations management results in better decision-making. The outcome of better decision-making is more efficient mining yielding enhanced financial returns for the mining industry.

Jan 1, 2009

Silica-Kaolin Sand Wet Sizing The Bulgarian deposits of silica-kaolin sand are localised in the eastern part of the Danube plain. After wet separation the raw material yields two products - washed kaolin (different grades) and silica sand (different grades). The water washing technology includes: disintegration; spiral classification; hydrocyclone classification and dewatering of kaolin grades; hydroclassification; sizing using drum screens and dewatering of silica sand grades. Research and development program has started to improve the silica-kaolin sand separation in processing plants. Based on the raw material and tails characterisation data and the preliminary experiments using Derrick Stacksizer screening machines a silica-kaolin sand wet sizing technology was developed. The full-scale pilot flowsheet includes the following units: Derrick Stacksizer equipped with 0.43 mm opening Derrick Urethane Panel; 500 mm Flat bottom Hydrocyclone; Derrick Stacksizer equipped with 0.150 mm opening Derrick Urethane Panel; 100 mm Hydrocyclone and Derrick Dual Motor Linear Motion Machine equipped with 0.064 mm opening Derrick Pyramid Panel. The pilot-test data clearly demonstrate that the new silica-kaolin sand wet sizing technology is suitable for Bulgarian silica-kaolin raw material. There are possibilities to increase the silica sand recovery increasing the production of silica sand grade PK 0.16 and starting the production a new grade PK 0.10.

Sep 13, 2010

In recent years a number of explosive blends including ANFO, emulsion and watergel products have been used in a variety of ground types and applications. These `standard' explosives' technologies are not new, but out of the uses and applications, have sprung a new generation of tailored explosives that match the ground type and the operating environment. This is in stark contrast to the norm, where various patterns and loading configurations have traditionally been designed to accommodate the explosive. This paper discusses these tailored explosives and the explosives' technology behind why they work. Active tailoring of explosive formulations can save mining dollars while essentially leaving the explosive price unchanged. Tailoring explosives may lead to increased rock breakage, heave, digging rates; lower digging maintenance costs and in some cases replacing earth moving machinery altogether. Tailored explosives may have other benefits such as reduced over pressure compared with standard alternatives. The tailoring of explosive performance generally involves three major methods (other than changing the bulk density and sensitivity): (i) replacing fast burning reactants with slower burning reactants or vice versa; or (ii) leaving the explosive intact and diluting the entire explosive with slow burning or `inert' material; or (iii) changing the concentration of the fuel/oxidiser mix. When tailoring explosives for particular applications, authorising, testing, costing, manufacturing, and delivery systems must also be taken into account.

Jan 1, 1995

The Taupo Volcanic Zone (TVZ) is the largest active volcanic belt in New Zealand. It is

Jan 1, 1987

About 3km2 of the central Luise Caldera, in which the Lihir orebody is located, is geothermally active wit.lj gas seeps and fumaroles, and in some areas, a water table at boiling point.The proposed mine, adjacent to Luise Harbor, will be excavated to more than 200m below sea level and will extend into the geothermal system to depths at which current rock temperatures are 170¦C.

Jan 1, 1994

The Bureau of Mines, with a history of mining research since 1910, still seeks improvement in safety and health along with improvement and competitiveness in the mining industry. Much promise of such improvements lies in new technology, and this is particularly the case in the still growing coal mine sector, although much Bureau research is long term, high risk, aimed at new concepts.The miner's environment is a primary concern, involving technologies of contaminant monitoring and control in high production scenarios. Contaminants arising from diesel use, alternatives to high speed rotary cutting and more efficient dust removal are being addressed, and drilling efficiencies, better monitoring through unitising operations and insitu rock dust monitoring are particular features.

Jan 1, 1991

By Cowie WJ, Utting BS

The alluvial gold industry of New Zealand is based on the placer deposits in Otago and on the West Coast. Production from these since discovery in the 1850's has been an estimated 480 tonnes (15 million ounces) of gold. Annual output has expanded continuously since 1980 and is expected to be over 2 tonne of gold for 1989.Following a historical review, the characteristics of typical operations, which use hydraulic excavators and mobile trommel units are discussed. Descriptions are then given of alluvial activities in Otago and on the West Coast.

Jan 1, 1990

The Ok Tedi copper and gold mining project is located in the headwaters of the Fly River system in western Papua New Guinea. The project's Feasibility Study was completed in 1979, and in- cluded a preliminary environmental assessment and an environ- mental management program. Construction commenced in 1981, an environmental impact study was completed in 1982, mining and treatment of gold ore commenced in 1984, staged construction of copper ore processing facilities took place during 1986-1988, and a further major environmental study was carried out for the operat- ing mine during 1986-1989. A very considerable data base of environmental information has been assembled by means of a comprehensive monitoring program. Environmental management criteria applied to the Project have reflected the stages and nature of development and operation. Criteria have been designed to regulate potential environmental impacts in the Fly River. An Acceptable Particulate Level of suspended sediment is the principal criterion. Compliance is con- ditional upon -a limited reduction in fish biomass, and upon dis- solved and particulate copper concentrations not exceeding predicted values at various locations throughout the river system. The criteria were established by the Government of Papua New Guinea following evaluation of environmental studies undertaken by the mining company. Compliance is checked by a detailed monitoring program, frequent reporting and statistical evaluation of monitoring results.

Jan 1, 1991

The Carnilya Hill Mine, a joint venture project between Western Mining Corporation Limited (WMC) and The Broken Hill Proprietary Company (BHP), is a nickel sulphide deposit being developed by the Kambalda Nickel Operations (KNO) of Western Mining Corporation. Seven months elapsed from the time a decision to proceed with the project was taken until the first ore production. During the first month of operation a new KNO record for decline development was set. Equipment used includes an electro- hydraulic drill jumbo, 4 cubic metre front end loaders, and 35 tonne haulage trucks.

Jan 1, 1981

By R L. Brathwaite, R Carver

The REGCHEM (Regional Exploration Geochemistry) database of open file mining company data, managed by GNS Science, has recently been upgraded with the compilation of additional data, especially for the Otago region (see http://maps.gns.cri.nz/website/minmap). In June 2007, data compiled for the Otago region included more than 2000 stream sediment samples from 19 surveys, more than 800 BLEG (bulk leach extractible gold) samples from 12 surveys and a few pan concentrate samples. The stream sediment samples were typically analysed for Au and As, and in many cases for other elements including Cu, Pb, Zn, Sb, W and Mo. The BLEG samples were analysed for Au and in some cases also for As. The main exploration target was mesothermal gold deposits in the Otago Schist, although one survey of the Otago Peninsula targeted potential gold deposits associated with the Dunedin volcanic complex. Geochemically, the mesothermal gold deposits are characterised by anomalous As and Au, with some also characterised by anomalous W and Sb, and these four elements are the best pathfinders in stream sediment geochemical surveys. The introduction of lower detection limits in Au analyses in the more recent stream sediment surveys and in the BLEG surveys enables the use of this element as the primary pathfinder for mesothermal gold deposits.

Jan 1, 2007

Increasing attention is being focussed worldwide on the strategic environmental assessment of mining projects, including consideration of cumulative environmental effects. In New Zealand there is now an end in sight for inappropriate delays in resource consent approval of responsible mining projects. This paper investigates six case examples of recently consented mining and quarrying projects, whose applications were notified. It also explores the nature of delays that occurred, the factors that contributed to the delays, and whether the consent process delivered fair and effective public participation and desirable environmental outcomes.

Jan 1, 2005

By Pinghui J

The paper describes the detailed hydrogeological studies carried out prior to the sinking of twin shafts at British Coal's new mine at Asfordby, Leicestershire, UK. The test methods for assessing potential groundwater inflows to the shafts are discussed and details are given of the ground freezing scheme employed through the major aquifer zone in the Sherwood Sandstone at a depth of 375 metres. During shaft sinking pressure recovery tests were carried out to further assess potential inflows and the results are compared with those from the surface tests prior to sinking.

Jan 1, 1988

By Weyer J

Many existing computer planning programs for the mining industry focus either on big mining enterprises with a high production rate or on smaller operations for high value minerals. Big mining enterprises, like the hardcoal company `Ruhrkohle AG' in Germany have their own R&D departments which develop powerful computer programs for planning purposes, partly in co-operation with mining universities. However, there is a remarkable number of small- scale mining operations which are either not able to buy expensive hard- and software or don't have the skills for the operation of extensive software programs. Partly there is also a trend in using rule of thumb calculations rather than computer programs which need a lot of - partly unavailable - data. For this reason a computer program was developed which does not need expensive hardware and software and which can help the planning engineer in the selection of a limited number of possibilities. Until this time the planning engineer established two or three different cases and calculated the results with a pocket calculator. This could last some hours or even some days. Now he or she can use the computer program with a normal PC to compare the cases. All activities are menu-driven. The basis for all, calculations are fixed and variable costs as well as average performance for special activities. The paper gives an example for a possible planning situation in fluorspar mining (originally this program was developed for the fluorspar enterprise Lengenfeld in Germany). It shows the initial situation, the main structure of the program, the input logic and the results. Benefits, limits and possible extensions of the program are discussed.

Jan 1, 1995

By Henley R, Harris L

High resolution airborne magnetic and radiometric data have been shown to optimize exploration for epithermal gold deposits in the vicinity of Charters Towers, northeastern Queensland. The radiometric data allow extrapolation of poorly outcropping geology to provide a cost-effective mapping technique, even at exploration scales (eg. 1:25,000). At a regional scale (eg. 1:100,000) the magnetic data reflect the regional tectonics and divide the area into domains for the application of different genetic models. For example: 1. the Ravenswood Batholith is characterized by multiple intrusions dating from Ordovician to Permian age. The polarity of the magnetic anomalies implies an age for the intrusions and indicates a deposit style for exploration. 2. extensional and wrench tectonics along the northern margin of the Drummond Basin are interpreted from the magnetic data and indicate favourable blocks for detailed exploration. Genetic exploration models may be tested in favourable environments by the recognition of geophysical signatures. These signatures reflect structural, lithological and alteration patterns arising from controls on ore deposits and can be applied at regional or detailed scales.

Jan 1, 1989