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By G Cooper

The Société Nationale Industriel et Minière (SNIM) is expanding its ore and concentrate production capacity in Mauritania, West Africa. This government-controlled mining company has been in production since 1963 and currently exports some 12 Mt/a.SNIM is presently doubling its magnetite concentrate production at the Guelb el Rhein mine. An existing processing line will have a second parallel production line of 4 Mt/a added. The mine is located some 600 km inland from the Atlantic coast in the heart of the Sahara Desert.The metallurgy of the ore is reasonably straightforward. It is a magnetite banded iron formation that is amenable to magnetic separation. While the existing plant uses semi-autogenous grinding and dry magnetic separation, the new processing line will use HPGRs, dry magnetic separation, and a wet milling and magnetic separation circuit for treating middlings.The process choices refl ect the scarcity of water in the region, the high cost of locally generated power and the operating experience and preferences of SNIM. Dust control in the desert environment has been a particular challenge.The metallurgical design aspects as well as the infl uence of the environmental and commercial aspects of the project are presented.

Jul 11, 2011

By D Deb, R Pramanik

This paper presents a generalised methodology in smoothed particle hydrodynamics (SPH) framework to analyse dynamic failure process of rock mass having natural joint under blast-induced stress wave and expansion, and penetration of high pressure gaseous product. The necessary interactions of gas-rock are incorporated in the model which describes features of coupling between damage and plasticity in tension and compression respectively. A Drucker-Prager formulation of plasticity is used to model the behaviour of aggregate field and the Grady-Kipp damage model is employed for tensile strain. These two material behaviours are then brought together within the framework of interacting continua. The model relies on the Drucker-Prager plasticity surface to predict the dilatancy aspect of the material response and to account change of strength according to the strain rate effect. Three numerical examples are presented with rock joint and multiple blastholes.CITATION:Deb, D and Pramanik, R, 2015. Smoothed particle hydrodynamics modelling of blast-induced fracture processes in naturally jointed rock medium, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 65–70 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

WHEN reading reports on reefs and lodes, one often comes across the statements "short shoot," "narrow shoot," "wide shoot," & c.From a number of reports in the writer's possession, some by members of the Geological survey, it is plain that the words "short," "narrow," "wide," "long;" &c., are used somewhat carelessly.In one official report on a certain field, for instance, the reefs are described as having "short, rich shoots"; another report on the same field states that "the reefs were characterized by narrow shoots, rich at the surface." Again, Charters Towers is described as having "wide shoots"; another writer says they are "long shoots. "The writer has read again of "short shoots which went down like pipes," and of "narrow shoots of limited extent." No doubt one can make out what is really meant, but the language is mixed. It is apparent that "narrow" is meaning the same as "short," and that the shoot has not much length in a horizontal direction. Nothing is said about the thickness or width of 'said shoot, or its depth. The "wide" shoot is evidently a "long" one; its thickness 01' width and depth is not specified. When we consider these terms, it is seen that only a few words are needed, and that these few should (as they do) have a definite meaning. In the course of his mining experience, the writer has seen shoots of almost all sizes, and some have been very long (in horizontal measurement), and have been followed down for great depths, these shoots being the best type-Charters Towers, Walhalla, &c., are examples.

Jan 1, 1909

By Van Weert G

Ferrous chloride solution pyrohydrolysis is a successful IICI regeneration process which is carried out in either a spray roaster or a fluid bed. Pyrohydrolysis is not restricted to ferrous chloride only, every metal chloride can theoretically be hydrolysed. In practice, however, the conditions for ferrous chloride pyrohydrolysis differ from those of many non-ferrous metal chlorides eg zinc, lead and cadmium. Hence, a pyrohydrolyser could function as a ferrous/non-ferrous separator, eg an iron oxide and zinc chloride separator. Most pyrohydrolysers operate on solutions, in which case more than 50 per cent of the process energy is needed for heating and evaporating water. However, this disadvantage would be diminished by feeding a slurry to the reactor. Against this background it was decided to investigate the chloridisation of zinc ferrite which is an iron bearing solid with a non-ferrous impurity, and subject to processing and disposal problems. Synthetic zinc ferrite was chloridised in a tube furnace. The gas atmosphere in the tube furnace resembled that of a fluid bed pyrohydrolyser and consisted of HCI, 1120 and nitrogen. Gas composition, temperature, residence time and sample mass were varied. The experiments showed that complete (99.6 per cent) zinc extraction from synthetic zinc ferrite was possible in a simplified pyrohydrolyser atmosphere at 1100 K in four hours. The zinc ferrite was converted into gaseous zinc chloride, and hematite and magnetite solids. It was also found that zinc removal from the zinc ferrite lattice caused not only rccrystallisation of the zinc ferrite into hematite, but also hematite crystal

Jan 1, 1993

By K Biegaj

The paper describes challenges the author has encountered on Australian underground gold and nickel mines over the last eight years, when recovering high-grade gold/nickel bearing mine floor material with a mobile supersucker/giant vacuum cleaner and other equipment. Whilst for a number of years the mine floor vacuuming and other mine floor clean-down technologies have been accepted/adopted and are working well in other parts of the world and on the South Australian opal mines, regrettably, they have not yet gained acceptance of mining executives and mine managers of gold and metal mines in Australia, who still elect to leave the never to be recovered gold/metal behind or to put it plainly - waste it.For reporting purposes during the mining process, the portion of gold/metal included in calculation of ore reserves prior to obtaining capital funds for their development, continues to be camouflaged in various reconciliation and call factors. This approach, ie wasting of capitally developed and already broken ore stocks should be viewed by the shareholders as totally inappropriate to say the least, especially with the current gold and other metals prices.The author attempts to provide answers as to why the technology referred to above has not yet been accepted on Australian gold and metal mines and outlines the way forward.CITATION:Biegaj, K, 2012. Why do shareholders and mining executives allow mine managers to leave behind high-grade broken ore underground?, in Proceedings Narrow Vein Mining 2012 , pp 197-206 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 26, 2012

By Frazer E. J, Lwin T

Measurements of coulombic efficiency (QE) for zinc electrodeposition were carried out under mass-transfer-controlled conditions using a rotating disc electrode in synthetic acidic zinc sulphate solutions. Various methods of solution preparation and purifi- cation were investigated using reagents vary- ing from analytical grade to high purity; the purest solution was obtained-by dissolving 99.9999% zinc (Koch-Light) in sulphuric acid solution (BDH Aristar). Improvements in sol- ution purity did not necessarily increase QE, especially where apparently beneficial impur- ities (e.g., Pb) were initially present. The maximum QE obtainable through variation of temperature (T), current density-(i) and elec- trode rotation rate was established using a statistical optimization technique. The QE was determined principally by T and i, with significant interaction between these factors in the highest purity solution. QE contours, which gave an overall view of solution per- formance, were constructed and predictions about the response under conditions similar to plant practice were made. Wark's Rule (the dependence of QE on zinc/acid ratio) was obeyed in the purest solution over the range of composition commonly encountered in zinc plants. High concentrations of Na2SO4 and K2SO4, which occur in some plant solutions, were found to increase QE marginally ("1.2%). The intrinsic effects of individual impurities such as Cu and Ni were evaluated by additions (up to 5 ppm) to the purest solution. Decreases in QE were found to be minimal at the impurity levels normally encountered in zinc plants.

Jan 1, 1987

By C X. Zhang, W K. Ru, S C. Hu

To study the creep properties and the energy evolution characteristics of the weakly cemented rock (WCR) in western China, the creep deformation damage law of weakly cemented mudstone (WCM) under graded loading and the energy evolution characteristics of each creep stage were analysed based on the triaxial graded loading creep test of WCR. The results showed that as the confining pressure increased, the creep failure strength of the WCM increased from 9.5 to 24.8 MPa, and the relative displacement of the mineral particles in the mudstone increased gradually, resulting in a reduction in the fracture angle from 79.7° to 58.3°. At the same stress level, the strain energy Ue, the total energy U, and the dissipation energy Ud all increased as the confining pressure increased, but the growth rates of U and Ud decreased gradually, while the growth rate of Ue remained high. At the end of the stable creep stage, Ue increased slowly with the confining pressure, while U and Ud increased rapidly with the confining pressure, and their growth rates were basically the same. At the end of the accelerated creep stage, the growth trends of these three energies were all positively correlated with the confining pressure, Ue was significantly lower than that at the end of the stable creep stage, and Ud and U were further increased. These results revealed the unique creep properties and energy evolution characteristics of the WCR, providing a theoretical basis for long-term stability control of roadways that are built with WCR.

Nov 29, 2022

Comprehensive occupational health and safety legislation in Australia is comparatively recent. It follows the examples set in U.S.A. and U.K. a decade or more ago. In Western Australia the Occupational Health, Safety and Welfare Act was proclaimed in April 1985. It still has a long way to go before it achieves all its objectives. The mining industry has developed a substantial body of health and safety regulations under the Mines Regulation Act. Considerable practical expertise in such matters already exists, much of it developed from hard won experience. As a result it would prefer not to become engulfed in the new legislation. It would prefer to build upon the cooperatively developed policies and workable practices in the field of occupational health and safety with which it is familiar. Associated Minerals Consolidated Ltd. is a leading mineral sands producer in Western Australia and has continuously developed its occupational health and safety policy and practices. Under the banner of "Resource Control", AMC seeks to provide a safe and healthy working environment at all times. This is being achieved through a strategy of a policy, a defined organisational structure and a detailed programme, which together comprise the "Resource Control System". Some of the activities and achievements of AMC in the field of occupational health and safety are compared with the objectives of contemporary legislation, and details of some of the specialised areas of the Resource Control Programme are discussed. The paper will also highlight and discuss impractical areas of potential legislation.

Jan 1, 1986

The iron ore deposits of-the Port Hedland distract of North-Western Australia are associated with banded-sedimentary iron., formations that.form part of the local succession. of folde.d..and faulted Archaean volcanic and sedimentary. rocks., The iron formations are regarded as the pr.otore,beds or sources of.the. iron which became;.,c,o.ncentrated by supergene.,processes. to form c,omznercial grade.. iron ore deposits,, ;-ò; Iron oxide ' deposit's occurring in"situ' within' the prot'ore beds are considered to be of residual--repplacement,origin`, due to supergene leaching of gangue minerals and deposition of secondary iron oxides in their'place'. Two types of deposit have been recognized. Lode deposits are deep lenses of massive hematite located adjacent to major, fau.lts... - These; deposits are-thought-to be very.,,old' and-to: have originated by supergene processes:.. during the, long: period of_ erosion represented- by the major, unconformity between the, Archaean .rocks and the, over!.

Jan 1, 1964

By Lawson F

Pyrite concentrate and calcine from the Nanjing Lead-Zinc-Silver Mines, China, were leached with aqueous cyanide and thiourea solutions. More than half of the contained gold and silver was able to be extracted from the roaster calcines. The very fine dissemination of precious metal grains, high roasting temperature (850 - 900°C) and residual sulphur are believed responsible for the Iow extractions.A recovery of about 70 per cent for both silver and gold was able to be obtained with cyanide and with thiourea leachants when the pyrite was roasted in the laboratory at temperatures between 600 and 650°C.Thiourea, as an alternative leachant, has received much attention recently and a series of constant potential leaching tests was conducted.When the thiourea to formamidine disulphide mole ratio was about two, the precious metal extraction was greatest. In the Nanjing calcined material, this occurred at a potential of about 210 mV relative to a standard calomel electrode.

Jan 1, 1987

By H Lieberwirth, M Pfeifer, F Heinicke

HPGRs (high pressure grinding rolls) have been developed within the last decades for energy efficient processing of a wide variety of ores. Special interest has been raised by projects increasing the capacities of processing plants by installing HPGRs prior to ball mills. Bond ball mill tests have been used for decades as a base for ball mill dimensioning in mineral circuits. For final CAPEXOPEX considerations of the processing circuit, one key question is about the level of grinding energy split between HPGR and downstream grinding stages. This is especially interesting if the downstream process comprises multiple grinding stages combined with separation steps. The paper presents investigations on grinding energy consumption, size distribution and microfracturing of HPGR products, which affect the efficiency of the whole comminution and sorting process.

Aug 24, 2022

By Folie M

Energy models are evaluated according to their contribution to policy decisions. The view taken is that if any model is to provide policy insights, it should be based on economic theory. The difference in modelling methodology between economists and technol- ogists is discussed. The technique of energy analysis is criticised. The basic structure of some of the large economic models is presented and their policy usefulness is Discussed.

Jan 1, 1977

Only West Australian entrepreneurs and Queensland politicians generate more debate than the uses and abuses of expert reports. Indeed, there are 300 of us here today to debate the very issues that, in general, have been unsatisfactorily managed by regulators and industry to date. I imagine Trevor Sykes will have some interesting stories to tell tomorrow morning in describing "Mines that weren't quite".

Jan 1, 1989

The role of marketing in the development of a new project will be affected by political, commercial and technical pressures. Marketing success will be determined by the ability to predict and react to tomorrow's environment. In the Australian coal industry there is an emerging transition from production to marketing orientation. As a result, greater technical awareness of customer needs will be required. In particular, the industrial product nature of coal markets will need to be recognised. Greater attention will also need to be paid to product options and quality in mine planning. Marketing personnel will become more involved at every phase of the development of a new mine.

Jan 1, 1983

An increase in the silver to gold ratio with increase in depth in the main ore shoot of the Crown-Crescent lode in the Emperor gold mine, Fiji, was found to be due mainly to vertical zoning of gold-silver tellurides. The zoning resulted from a two-stage sequence of ore mineralization.The application of some recent studies of the synthetic Au-Ag-Te system to natural gold-silver telluride assemblages is discussed.

Jan 1, 1971

By A Boeing

Rock-breaker automation and remote operation improves the safety and efficiency of mining operations. This paper presents an overview of the Rocklogic rock-breaker automation system architecture that provides collision avoidance, automated parking and remote operation functionality. The system consists of a distributed computer control system that interfaces with sensors attached to the rock-breaker, the rock-breaker hydraulics and the site infrastructure. We present results of an automated Transmin rock-breaker installed in a production environment at an underground Australian mine site. The system has been in production use for over 900 days, during which there have been no reported collisions and 100 per cent adoption of the remote operation technology. As a result, Rocklogic has significantly improved the safety of rock-breaking operations and reduced the rock-breaking cycle time, thereby improving the site’s overall throughput.CITATION:Boeing, A and Douglas, E, 2014. A remotely operated robotic rock-breaker with collision avoidance for the mining industry, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 131–136 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

By Rais SA

In June, 1986, Freeport Indonesia, Inc., in conjunction with Out- okumpu USA, laboratory tested the Flash flotation concept on Primary ball mill underflow. These laboratory results indicated a possible 10% increase in precious metal recovery and 0.6% increase in copper recov- ery were available over conventional methods. By October of the same year two Outokumpu Skim Air SK-240 units were operational on one mill circuit and were achieving 5 to 10% increased recovery in precious metals with equal copper recovery at one percent higher final concentrate grade. Two more cells were purchased and installed on the remaining grinding circuit in July, 1987. As part of the installation of the Skim Air cells, an existing cluster of six 508mm Krebs cyclones were replaced by four 660mm Krebs cyclones. To reduce high circulating loads, these new cyclones were made horizontal at 45 degrees. This arrangement succeeded in reducing the mill circulat- ing load by 100% and has allowed for a 10% increase in throughput at the same grind.

Jan 1, 1988

By Ohga K, Isobe T

Basing upon many and long practical experiences of gas drainage from coal seam and results investigations on the gas flow through in si-tu coal seam using tracer gases,it became clear that solid coal itself is hardly gas permeable or has extremely low gas permeability. Almost all of gas flows from a coal seam into boreholes through fracture net- works intersecting with them.Primary and secondary fractures in coal seams differ in their size and continuity from place to place according to differences of the coal strength and the stress conditions. A lot of gas can be drained through boreholes which intersect with many and/or wide fractures. A mathematical model for gas flow from a coal seam to a borehole through a discoidal fracture is proposed. From the numerical analyses,the apparent radius of the discoidal fracture in this model is shown to be a good indication of the gas drainage ratio. In addition to this,an atempt to make fractures around a borehole using high velocity water jet(ca.lmm dia.,300-700atm., 100-200 1/min.) is introduced.

Jan 1, 1982

During the intial two years (1972 - 1974) of exploration at Telfer, water require- ments were limited to supporting a 50 man camp and diamond drilling to verify thickness and grade of the stratabound ore deposit. Water bores were drilled to intersect the Middle Vale Reef down dip from its outcrop about 70 metres below surface. The MVR reef is an oxidized pyritic horizon which contains 30% - 65% sulphide below the zone of oxidation and forms a highly porous leached gossanous zone to a depth of 100 metres. Surface run-off water from the low hills associated with the Main Dome structure have led to annual re- charge of this extensive aquifer which MAP AREA Lake Waukarlyearly Permian rocks Precambrian basement - - ~;; rocks Sand d.n.s pò. _ « Drainage sg 1 qo~ (`-~.~ ? ò;+ Palaeochannel and 1 d {- subsurface drainage % GLENN BOREFIELD PASSMORE FAULT ;òTsI1. G-OId MIns BOUNDARY oChr~st as t .` Pool 4, 1 j`` Lake Dora òt ~daN 22' 0, 50 Niter KILOMETRES Fig 1. Telfer district map, Great Sandy Desert, Western Australia.

Jan 1, 1988

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