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By Daniels E. J, Morgan W. A

In response to the increase in consumption of galvanised steel for automobiles in the last decade and the problems associated with remelting larger quantities of galvanised steel scrap, a process is being developed to separate and recover the steel and zinc from galvanised ferrous scrap. The zinc is dissolved from the scrap in hot caustic using anodic assistance and is recovered electrolytically as dendritic powder. The dezinced ferrous scrap is rinsed and used directly. The process is effective for zinc, lead, and aluminum removal on loose and baled scrap and on all types of galvanised steel. The process has been pilot tested for batch treatment of 900 tonnes of mostly baled scrap. A pilot plant to treat continuously loose scrap, with a design capacity of 48 000 tonnes annually, has been in operation in East Chicago, Indiana since early in 1993. The first 450 t of scrap degalvanised in the pilot plant have residual zinc below 0.01 per cent and sodium dragout below 0.01 per cent. Use of degalvanised steel scrap decreases raw materials, environmental compliance costs, and opportunity costs to steel- and iron-makers. Availability of clean degalvanised scrap may enable integrated steel producers to recycle furnace dusts to the sinter plant and EAF shops to produce flat products without the use of high quality scrap alternatives such as DRI, pig iron, or iron carbide. Recycling the components of galvanised steel scrap saves primary energy, decreases zinc imports, and adds value to the scrap. The quantities of zinc available by the year 2000 from prompt and obsolete automotive scrap will approach 25 per cent of zinc consumed in the major automotive production centres of the world. Zinc recycling from galvanised steel scrap, either before or after scrap melting, will have to be Implemented.

Jan 1, 1993

By Aziz NI, Guo H

Most of the existing models of the mechanisms of drilling and cutting processes are oversimplified in both stress state and failure criterion. On the other hand numerical modelling techniques are a more versatile method with great potential for development. In reviewing drillability and predicting performance of excavation machines the empirical tests, which simulate the physical breakage action in excavating processes are seen to be the best in terms of penetration rate predictability. Future methods of determination of drillability should concern the breakage characteristics and rock abrasivity involved in the two basic types of attack, i.e., percussive and rotary drilling.

Jan 1, 1988

By Will D

This presentation is to outline the current practice of mechanised stoping a one-metre wide, gold bearing ore body to optimise fragmentation, minimise dilution and reduce stoping costs.Coolgardie underground operations have historically been mined using traditional shrink stope methods, but in this recent economic environment (with falling gold prices and high costs of traditional methods) it was necessary to look for alternative methods in order to reduce costs and increase productivity.Although still in a learning and refinement phase, CGNL is satisfied that it is feasible, practical and more economic to use mechanised long up-hole stope and long-hole rising methods to significantly reduce the mining cost, reduce dilution, increase safety and increase productivity three-fold compared to traditional airleg methods used throughout the Fasten Goldfields.

Jan 1, 1993

The estimate of an ore reserve is a vital statement made about a mineral occurrence by an evaluator. It is important that such a statement communicate reality to all groups involved in a mining project, be they technical, financial, company directors, Stock Exchanges or the public. Ore reserve statements should state both resources and recoverable ore reserves. Resources may be important in very long term considerations, (because mining, metallurgical technology and economics change with time) but recoverable reserves are todays reality. The important factors contributing to recoverable reserves (in a general sense) are geology, mining method (and its impact on dilution and ore loss), metallurgical recovery, costs and commodity prices. These all need to be reflected in the ore reserve statement. In this paper recoverable ore reserve concepts across a wide range of orebodies are considered and discussed with respect to geology, mining method and ore reserve calculation procedures.

Jan 1, 1987

By Bowling K. McG, Hamilton J. D G

The influence of three important para- meters which affect the induration of iron-ore pellets, viz temperature, time, and lime content, have been assessed in terms of internal pellet structure and commonly-used pellet quality criteria. The pellets studied were produced from a typical hematite ore from the Pilbara area of Western Australia, using a 25 cm dia. pot-grate test rig. Isothermal laboratory induration tests were conducted in accordance with a statistically-planned programme. The internal structures were studied by optical microscopic examination of polished sections of the test pellets. The effects of SFCA (silico- ferrite of calcium and aluminium) and slag formation, matrix consolidation and grain modi- fications were studied, and have been related to pellet properties and to the time/temperature histories produced by the firing conditions chosen. The implications of the data for commercial pellet plant operations are discussed.

Jan 1, 1974

By Loo R

The Paper discusses the size and extent of in-pit dust suppression problems created by iron ore mining in the Pilbara region of Western Australia. Dust problems associated with drilling, loading, hauling and tipping are discussed indicating the large quantities of water which can be applied for dust control and attempts that have been made to rationalise this water usage to obtain maximum benefits from the applied water. The magnitude of the problem and the quantities of water involved can be appreciated when one realises that 275 000 tonnes of rock are moved on Mt. Whaleback each day and that there are 40 km of haulroad within the open pit. Initially dust suppression was limited to the spraying of haulroads by large water tankers. Now dust suppression is practiced during drilling and after blasting, wind blown dust is reduced by application, using water cannons,of large quantities of water to floor stocks prior to loading operations as well as by the installation of 16 km of automatically controlled fixed sprinkler reticulation on the main semi-permanent haulroads. The methods used to assess the water requirements for in-pit dust suppression are discussed and the extensive development testing used to evolve the present installations are 1. Environmental Superintendent Mt. Newman Mining Co. Pty. Ltd. Newman, W.A. 2. Chartered Consulting Engineer, Perth, W.A.

Jan 1, 1979

An ongoing research program into surface subsidence over Room and Pillar coal mining is described. A subsidence monitoring network has been established for one Room and Pillar mine in the West Moreton Coal Field of South East Queensland, at which pillar extraction is being conducted. The maximum measured subsidence to 28 January 1986 was 638 mm, with movement continuing. Analysis of the monitoring data with view to application of the subsidence pre- diction theory developed by Kowalczyk (1972) is discussed. The Kowalczyk theory provides predictions of subsidence depression, slope of surface, horizontal displacement, surface curvature and horizontal strain, for both the Partial and Total Settlement cases. The development of subsidence with time is also investigated and a preliminary analysis conducted.

Jan 1, 1986

By Omnes G

Sixty Schlumberger electrical soundings were carried out in the Depot Springs area, near Agnew, Western Australia as part of an investigation into the availability of groundwater for the Agnew nickel project. The object of the survey was to locate calcrete aquifers related to Tertiary drainage channels on the Pre- Cambrian surface. The electrical soundings were initially interpreted using sets of master curves and auxiliary point methods. Electrical sections were produced and contour maps prepared of apparent resistivity for AB=80m, total conductance of the overburden and transverse resistance.

Jan 1, 1975

An intensive safety campaign at Mount Isa Mines Limited from 1956 to 1966 saw the lost time accident frequency rate fall to half its original level. A review of the safety programme was carried out in 1967 and in 1968 the Five Point Safety System was introduced. The seven years since its introduction have been years of significant achievement both in production and safety. Improving safety is a fundamental part of Mount Isa Mines Limited's policy and this system has been a major tool in implementing that policy. To be successful personnel need to be prepared and trained for its introduction and subsequently counselled on its use. A carefully prepared programme is required to phase in various aspects of the system and to make use of complementary steps. The system has been a success and it is anticipated that the continued drive to improve the use of principles of the system will further improve safety. It is hoped that this paper will be of value to those personnel concerned with industrial safety in Australia.

Jan 1, 1975

The first hydraulic roof supports were installed underground in 1950s and ever since that time engineering developments have improved the supports in many different ways. However. advances in three main areas, the roof support mechanical design, hydraulic engineering and electronics have ultimately led to the point where, 35 years after that first installation. automation has been achieved and is now commonplace.The history of roof support automation has involved the continual integration of high technology engineering. Thera ate further possibilities for the future which combine to give some idea of the likelihood of there ultimately being a completely manless face.

Jan 1, 1991

By Culshaw MG, Deaves AP, Bell FG

The accurate prediction both of the water ingress into sub-surface excavations and the nearby groundwater pressures is of fundamental importance to the control of the stability and flooding of tunnels or mines constructed below the water table. Predic- tions are usually based on laboratory and in situ permeability determinations together with observations of groundwater conditions in boreholes. Although established theoretical methods provide a basis for prediction, the actual ingress depends on many factors. The objective of this paper is to explore the geological controls on groundwater conditions, and the available methods of prediction of both groundwater flow and pressure are outlined. Salient points are emphasised by reference to a case history involving the construc- tion of a tunnel in a faulted and mixed sequence of sandstones, siltstones, shales and coals. Water ingress quantities have been monitored for a variety geological and geotechnical conditions including heavily faulted and mine disturbed ground. The overall results are discussed with reference to the relevant hydrological and geologi- cal conditions in terms of the geological structure, lithology and rockmass condition as well as the construction methods.

Jan 1, 1988

By S Ellis

In January 2008 Chirano Gold Mines Limited committed to expansion of the Chirano Gold Project from its existing design capacity of 2 Mtpa ROM ore to a new design value of 3.5 Mtpa. In addition to increased throughput, the design had to contend with increasing ore hardness and competency, while at the same time make cost effective use of existing equipment with minimum disruption to existing production. The solution adopted involved some novel approaches including tertiary crushing and operation of the SABC circuit in overflow ball mill mode and parallel elution with a common acid wash column. This paper describes the approach taken to the design of these elements to achieve a cost effective and safe capacity expansion.

Aug 8, 2011

By M Berndt

Four siltite-argillite rock samples were characterised (particle size, chemistry, mineralogy) and subjected to laboratory dissolution testing for 36 to 298 weeks. In two samples sulfur (0.99, 1.69 wt per cent) occurred largely as pyrite, and in the other two samples sulfur (0.96, 1.93 wt per cent) occurred predominately as potassium jarosite. The observed rate of sulfate release from the pyritic samples was one to two orders of magnitude greater than that from samples containing potassium jarosite. Drainage pH values from the pyritic samples were one to two units lower and acidities were ten to 70 times higher than associated values from the potassium jarosite samples. Geochemical modelling supported the hypothesis that pH and concentrations of sulfate and potassium in drainage from the potassium jarosite samples were controlled by the limited solubility of potassium jarosite. This dissolution produced an iron-dominated mineral phase, but iron concentrations in the drainage were well below those predicted by ferrihydrite solubility.

Jan 1, 2003

By Holmes RJ, Sowerby BD, Watt JS

Major improvements have taken place in mineral and coal processing in the last decade. The development of nuclear on-line sensors that continuously analyse the material being processed has led to better control of metalliferous mineral processing and increased recovery of valuable minerals. The recent development of on-line techniques for analysis of coal is expected to be of similar Importance. Australian developments in on-line nuclear gauges are reviewed. These include systems for in-stream analysis of mineral slurries with comments on plant operating experience; on-line determination of ash in coal using low energy Y-ray transmission and pair production techniques; in-stream determination of solids weight fraction and ash content of coal in slurries with variable voidage; and on-line determination of moisture in coal, iron in high grade iron ores and sulphur in lead sinter.

Jan 1, 1986

By Walshe JL, Solomon M

The Emperor vein system lies on the eastern margin of the Tavua volcanic structure. This is of Miocene age and occurs in basalts(the Mba Volcanics) probably underlain at about 2 km by calcite-rich sediments (the Vatukoro Formation). The lodes are generally flatmakes, or steep fault fillings, or complex shatter zones, and consist of quartz and altered wall rock. In areas of open cavities it is possible to establish a paragenesis which involves five quartz stages and two ore mineral stages. The first ore stage contains calaverite, krennerite, sylvanite and native tellurium, the second petzite, hessite and native gold. The quartz stages are thought to have formed slowly (102 years) from boiling solutions of low salinity at temperatures varying with time from about 250¦C to 190¦C. The system was sealed, the temperature gradient near vertical and the mass flux small. The ore mineral stages probably formed relatively rapidly (101years) from boiling solutions at 250¦ to 200¦C when the system was mainly open. Gold deposition was probably largely a result of fall in aH2S due to boiling, the calculated solution concentration falling from a maximum of about 8 ppb at 250¦C to about 8.10-3ppb at 200¦C. Boiling is also probably responsible for an increase in a02 (by loss of H2) and fall in aTe2 (by loss of H2Te). The fluids are thought to have had a large component of meteoric water and to have been heated by plutons in the core of the volcanic structure. Stable isotope data indicate that they derived their carbon from the underlying Vatukoro Formation and their sulphur from sediments. Circulation may have been confined to the outside of the volcanic structure because of the relatively low permeability of the flows, pyroclastics and dykes within it.

Jan 1, 1987

By Yates M. G, Rowlands A. T

Most geostatistical techniques applied to the estimation of ore reserves assume relatively unifonn grade and thickness within an ore deposit environment. In shear-hosted mineralisation this rarely occurs. The distribution of mineralisation is controlled by the kinematic and geometric variation within the shear zone. Although the kinematic variation is dependent primarily on the temperature (and consequently the depth) of formation of the deposit, the geometric variation appears to be relatively insensitive to this parameter. Shoot mineralisation is controlled either by the intersection of secoodary shear planes (brittle deformation) or the stretching lineation of the mylonitic fabric (ductile defonnation).Once the shear geometry is clearly identified, it is critical to review the distribution of grade and thickness of mineralisation. The practice of cutting high-grade intersections without reference to the shear model leads to underestimation of the amount of gold in the deposit. High-grade shoots may occur as pipe-shaped bodies within the system; their identification is essential for both resource estimation and mine planning purposes.

Jan 1, 1991

By J-P Franzidis, M Esvelt, E V. Manla

The Floatability Characterisation Test Rig (FCTR) is a self-contained, highly instrumented, mobile pilot plant that is able to treat up to 2 tph solids. It consists of a bank of six 130 L WEMCO« SmartCells« and a bank of six 50 L WEMCO« SmartCells«. It was developed as part of the AMIRA P9 Project, primarily to determine ore floatability characteristics and to develop and validate flotation plant modelling, scale-up and simulation methodologies. However, it may also be used to carry out pilot-scale flotation test work. This paper briefly describes the circuit modelling, simulation and scale-up test work performed using the FCTR and the use of the FCTR in pilot-plant test work performed by the metallurgical staff at WMCÆs Kambalda Nickel Operations and Mount Keith Nickel Operation. At both Kambalda and Mount Keith the FCTR was found to be very flexible and straightforward to run, with an easily changeable circuit configuration and stable operation. Testwork was facilitated through having full stream sampling on all streams, and a high degree of instrumentation providing accurate measurement of process variables. The results obtained from the FCTR testwork were highly repeatable. As a consequence of using the FCTR, WMCÆs Kambalda Operation and Mt Keith Operation were able to complete a rigorous programme of pilot plant testwork more quickly than in the past, and with a high degree of confidence in the results.

Jan 1, 2003

By A Grace, C Sennersten, A Davie, R Lyu, C A. Lindley, O Goldstein, T Thomas, L De Macedo Camargo

Block modelling is a well-established method for modelling ore reserves as a basis for strategic mine planning and mine development. Off-Earth mining, particularly of asteroids, can benefit from block models; however, the significantly different characteristics of asteroids and their methods of mining require reconsideration of the geometry and annotations of block models. Terrestrial block models consist of rectangular prisms within Euclidean coordinate systems. Their labels and parameters typically include location within a mine-specific coordinate system, x, y and z dimensions, specific gravity, hardness, grades of metals of interest and so on.These data provide an input to mine design and strategic mine planning. Mining asteroids may require different coordinate systems (eg spherical, elliptical or cylindrical, rather that Euclidean) and attributes that vary from Earth-based block models. These include: variable gravitational vectors throughout the block modelrotational moment or accelerationrotation rates. Materials within asteroids may show different isotopic compositions. Asteroid mining has the unique characteristic of a mine being identical with an asteroid. The position of the asteroid/mine in space and its full orbital elements provide critical inputs to mission design and costing. Hence, the block model concept needs to be extended with this metadata. The orbital position and behaviour of the Earth must be included for active mine planning, and increasing automation of mine planning and operations needs to consider terrestrial weather and telecommunications infrastructure. Financial planning requires analysis of the net present value of extraterrestrial mining compared with terrestrial alternatives, so a fully automated mining enterprise should integrate terrestrial and extraterrestrial block models at different scales and resolutions. Blocks can be indexed via octrees, allowing for hierarchical scales that support analytics for deriving new knowledge and correlating features across different scales.CITATION:Lindley, C A, Sennersten, C, Davie, A, Goldstein, O, Lyu, R, Grace, A, Evans, B, Pentecost, D, Thomas, T, De Macedo Camargo, L, Craig, J, Salomao, G N, Hellicar, A, Biggins, D, Timms, G, Coombe, M, Shahriar, M S, Smith, G and Rahman, A, 2015. A multilayer 3D index tool for recursive block models supporting terrestrial and extraterrestrial mine planning, in Proceedings Third International Future Mining Conference, pp 289–296 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

Australian continental crust has accreted and consolidated by thirds: 1/3 during Archean time, 1/3 during Early to mid-Proterozoic time, and 1/3 during latest Precambrian to mostly Paleozoic time. The progression of orogenic systems and the crustal consolidations they represent seem not fundamentally different in basic orogenic processes from better known Mesozoic-Cenozoic examples in that accretionary, continental margin, collisional, and intraplate intracratonic inverted and/or reactivated systems are all recognizable in the tectonic evolution ofAustralia.

Jan 1, 1995

By Roe P, Lowell A

This paper outlines software development and design work carried out by Mincom Pty Ltd in collaboration with Capricorn Coal Management (CAPCOAL) for computer based design of rehabilitated strip mine landforms at German Creek Mine. Current developments and future application areas for this software are also discussed in relation to other mines in Central Queensland. The development program was initiated in response to statutory requirements placed on mining companies in 1990 to produce a five year Plan of Operations which was to include a contour plan of the final rehabilitated mine landform at the end of the five year planning period. This plan was to be submitted to the Department of Resource Industries (DRI) by 1 December 1990. Due to the limited time given to prepare the plan, a work program was formulated in collaboration with Mincom Pty Ltd to develop suitable software to carry out the design work and provide the required plans and quantities. The software had to include computer based methods to allow design of the proposed landform in line with the rehabilitation strategy adopted by CAPCOAL at the time.

Jan 1, 1991