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By Campbell Brown G A

IN 1904-5 diamond drilling operations in the Mount Morgan mine proved the presence of some millions of tons of rich copper-gold ore, averaging about 45%to 50%silica and 22%Fe as sulphide. To smelt this ore in blast furnaces, without previous concentration, large quantities of basic flux were required. Unlimited quantities of cheap limestone were available at Marmor, on the GladstoneRockhampton railway, 50 miles from Mount Morgan, but the supply of iron flux was a more difficult problem. Smelting Operations started with one furnace in January, 1906, using as flux low-grade sulphide ore from the mine, containing very little silica. When the second furnace was blown in this was supplemented by ironstone from small deposits in the immediate district. It was recognized that these sources of supply would be insufficient to keep the full plant going after the third furnace had been blown in. Accordingly, the deposits at Kabra and Mount Etna were opened, neither of which proved capable of supplying the quantity required-viz., 1000 tons per week. Negotiations were meanwhile being conducted with the Marble Island Iron and Limestone Co. to obtain the right to mine at Iron Island, where a sufficiently large deposit was known to exist. Shipments from this source commenced in January, 1907, and ceased at the end of July of this year, when the metallic flux from...

Jan 1, 1911

In a high pressure rolls crusher two force components: the pressurising thrust and the rolling force can be measured experimentally. Computer analyses have revealed regular patterns of stress distribution in the confined material between the rollers. Based on the computer analyses and experimental results a one-dimensional comminution model has been developed.

Jan 1, 1995

This paper describes several sources of external dilution affecting the stope walls during underground sub-level and bench stoping. Factors which control ground behaviour such as the geometry of the openings, the influence of geological discontinuities, stress re-distribution and blasting practices are discussed. Crown stope instability due to stress concentrations induced by changes in the excavation geometry, is discussed and the most efficient ways to sequence blasting within a stope are analysed. Effects of undercutting by blasting, blast damage in the near field and cut-off slot blast designs are analysed. The influence of dynamic loading on the exposed walls as well as the practice of blasting fill passes within stope crowns are discussed.

Jan 1, 1995

By A G. Shellsh, R J. Henham, J R. Foley

The Porgera Gold Mine, west of Mt Hagen in PNG is a large open pit and underground operation currently producing gold at the rate of almost one million ounces per year. This deposit has produced some 8.8 million ounces to-date and has current reserves of 103.4 million tonnes @3.2 g/t Au. The Porgera Joint Venture has invested over $A1 billion in infrastructure in this project. Technical management of this operation involves the interrogation of some 700 000 metres of diamond drilling, some 50 000 blastholes per year, and very large volumes of laboratory, geotechnical, environmental and production reporting data. Over the past seven years this data has been consolidated into a single centralised, relational database which now acts as the single reference point for all the technical application systems used for surveying, grade control, production reporting, deposit evaluation and modelling. Data transfer to application programs and management systems is controlled by the centralised database, this process at times involving a two-way, real-time, binary data transfer. The benefits of a specialised database application include security and integrity of the data asset, ease of access, and performance in a multi-user environment. This replaced fragmented, inconsistent data sets stored inefficiently as individual, unindexed, variably formatted files associated with the different application programs. Most importantly, the database has allowed mine management at all levels to make timely, confident investment, cash flow and optimisation decisions as it provides the primary link between the deposit and operational data sets on one hand, and the application programs and management and performance measurement systems on the other. This paper discusses the economic value and importance of technical data in terms of the resource asset and the means by which this data is being managed and used at Porgera.

Jan 1, 2000

One of the biggest drawbacks of deciding upon a heap leach method of treating gold ore is the risk associated with the full-scale production heaps not performing as predicted by the testwork. This paper examines the key decisions that are taken in the design of a heap leach project, and suggests ways in which exposure to these risks can be minimised. It also looks at monitoring techniques to give early warning of problems and possible remedial actions.

Jan 1, 1994

By R F. Sandenbergh

Due to environmental considerations, mineral processing plants are increasingly recycling water to decrease the impacts of wastewater on environment and the depletion of fresh water resources. Industrial experience has shown that increasing recycling water in flotation typically negatively impacts the recovery and selectivity, especially in the selective flotation of minerals from complex sulfide ores. The major reason for the reduced selectivity is typically the inadvertent activation of sphalerite or pyrite by the heavy metal ions (HMI) in solution. These HMI are often produced during milling and flotation and absorbed by other minerals. In the normal flotation pH value range (8 - 10), these HMI are often in the form of precipitates or complex ions that may re-appear in solution or become active should conditions favour this. In this paper, microflotation, batch flotation and XPS surface measurement were used to investigate the use of HMI absorbents additions to the pulp to improve flotation selectivity of a complex sulfide ore. It has been demonstrated that HMI removal does improve flotation selectivity by facilitating more effective depression of the sphalerite. Microflotation and XPS surface measurements have shown that HMI absorbents compete with sphalerite to absorb HMI, and thus reduce the surface concentration of HMI on those sulfides. The practical use of HMI absorbents in complex sulfide ore flotation is also discussed.

Jan 1, 2005

Creating Value and Improving Environmental Performance by the Recovery of Valuable Products from Tailings from the Athabasca Oil Sands in Alberta, Canada

Sep 13, 2010

The Bau Goldfield lies in the southwestern corner of Sarawak in East Malaysia. Evidence of past mining in the form of open pits and adits can be found over an area of 250 sq kin, centred on the township of Bau. Chinese were mining gold in the district as early as 1820. The Bau Goldfield so far has produced approximately two million ounces of gold, from alluvial deposits and over 50 hard rock mines. The largest single producer was the Tai Parit mine (700 000 oz) which was operated by the Borneo Company from 1898 to 1921 and by a local Malaysian family from 1991 to early-1997. Over the past ten years, gold resources totalling around one nullion ounces have been delineated through systematic exploration using modern techniques, with the bulk of the resource hosted in two deposits (Jugan and Pejiru).Triassic to Jurassic andesitic volcanics and coeval intrusives are the oldest rocks that crop out in the Bau Goldfield. These igneous basement rocks are unconformably overlain by 500 m of late Jurassic, massive, micritic limestone which in turn is overlain by a 1500 in thick flysch sequence, composed mainly of shale. Basement rocks and limestone are exposed along the hinge of a ENE-striking anticline that passes through the Bau district (Bau Anticline). A NNE-striking belt of Miocene granodiorite porphyry stocks and dykes also passes through the Bau Goldfield. All of the known gold deposits lie within 5 km of this zone of intnisives, with a concentration of deposits at the intersection of the intrusive hell with the Rau Anticline.

Jan 1, 1997

By A Mirzaghorbnali, D Gilbert, R Burton, J Nemcik, N Aziz

Glass-reinforced polymer bolts, commonly known as fibreglass dowels and fibre-reinforced polymer or plastic bolts or plastic dowels are increasingly applied for strata reinforcement in mines as well as in concrete reinforcement in civil engineering. The most popular dowels used in coalmines are the 22?mm diameter fully threaded type. Fibreglass and plastic bolts are cuttable, easy to handle, lightweight and corrosive resistant. A series of tests were undertaken to evaluate various strength properties of fibreglass dowels. These included tensile failure tests by the double-embedment method, a single guillotine shear test and a double shear test, carried out on dowels installed in concrete blocks, and with punch shear tests. Punch shear tests were used to evaluate the dowel shear strength parallel and perpendicular to the fibreglass strands or elements direction of extrusion. The study found that the tensile strength of the 22?mm diameter fibreglass dowels was in the order of 30?t. In the shear testing, the peak shear load was influenced by the encapsulation grout type and the level of fibreglass axial pretension. Also, there was a nearly fivefold difference in the shear strength value of fibreglass dowels tested parallel as against perpendicular to the dowel axis.CITATION:Aziz, N, Gilbert, D, Nemcik, J, Mirzaghorbnali, A and Burton, R, 2014. The strength properties of fibreglass and other polymer-based dowels for strata reinforcement in coalmines, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 263–268 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

Two independent sets of observations from rifted con-tinental margins suggest a way to reach a quantitative under-standing of how the topography of rifted margins erodes. First, a prominent erosional escarpment, which demarcates an elevated, inland region of low relief from rugged, deeply-incised terrain on the seaward side, is the main feature of the geomorphology of many rifted continental margins. Second, apatite fission track ages from the southeast Australian and southwest Saudi Arabian margins scatter about constant Paleozoic ages over the higher elevations inland from the escarpment, but decrease systematically seaward of the escarpment to near-rifting ages approaching the coastlines. We have developed erosion models based on conservation of mass principles to explain these observations. These models seek to explain the "rejuvenation" of erosion at the time of rifting, initiation of the observed erosional escarpment, and its migration inland with time at a rate on the order of 1 km/10 yr. We find from the modeling that erosion at rift flanks and passive margins is fundamentally a non-linear pro-cess. The erosional development of passive margin topogra-phy has much is common with travelling wave solutions to non-linear diffusion-type problems, and to self-similar sto-chastic processes, such as diffusion-limited aggregation. We suggest that the fission track data record the thermal effects of erosional unroofing at rift flanks and passive continental margins. Models intended to explain the erosional develop-ment of continental margins must explain both the geomor-phology and the fission track observations as well.

Jan 1, 1990

By Withington J. T

The four major contracts for the construction of Museum Station are: 1) Installation of Soldier Piles, 2) Structural Contract including the temporary support, 3) Architectural Finishes which include Electrical and Mechanical Services and 4) Supply and Installation of lifts and escalators. Specific areas of interest include the fabrication, installation and removal of temporary support steelwork, the monitoring of ground loading, and the interface between the structure and. the temporary support. The information collated during construction confirmed the design assumptions and criteria. No major changes'were required in the design of the construction methods. The open cut excavation and construction of this major structure in an inner city area was significant by any standard and was successfully completed with minimum disruption to the public and without damage to adjoining or surrounding property.

Jan 1, 1981

By T Mahlangu

The leaching of gold in alkaline aqueous cyanide solutions may be reduced significantly by the passivation of the gold by a surface layer of polymeric aurocyanide. This passivation of the gold is typically countered by the presence of Pb(+2) species in solution, which may be present as an impurity in the solution, or specifically added for this purpose. The speciation and availability of Pb(+2) in typical cyanide leach solutions is illustrated as a function of pH, and the presence of S(-2), S(+6), Cu(+1) and Ag(+1) species. The probable role of the Pb(+2) species in efficient gold leaching is discussed.

Jan 1, 2007

By Gonzalez-Dominguez J. A, Dreisinger D. B

At Cominco's Zinc Refinery at Trail, British Columbia impurities are removed from zinc sulphate electrolyte by a two-stage purification process using zinc dust. Copper, cadmium and thallium are removed in the first stage whereas cobalt is removed in the second stage. Cobalt removal kinetics are affected by soluble antimony and copper additions to the electrolyte. This study was focused on the kinetics of cobalt removal by zinc powder cementation. Experimental variables included copper and antimony concentrations, pH and temperature. Common organic additives employed in zinc plants were studied to determine potential interactions with the cobalt removal process. Cementation products obtained from laboratory experiments and plant practice were studied using SEM. A number of significant results were obtained: 1. Copper and antimony ions were sustantially removed from solution during the early stages of the cementation reaction (within the first 15 minutes). Cobalt cementation kinetics are slow and follow a first order kinetic regime. 2. A drop in the cobalt removal rates can be correlated with a rise in the Eh of the slurry. 3. Ligninsulphonate, Percol 351 and animal glue at levels of 2 mg/L significantly impede cobalt cementation.

Jan 1, 1993

The Charters Towers goldfield in northeastern Queensland produced over 206 tonnes of gold from gold-quartz veins hosted by Mid-Palaeozoic granodiorite, tonalite, diorite and to a lesser extent amphibolite-grade meta-sedimentary schist and meta-igneous rock. Mineralisation occurs in grouped, moderately dipping shear zones with altered wallrock rafts and a complex network of quartz veins.Over 75 per cent of the production came from three main vein systems in the central goldfield: the Brilliant, Day Dawn and Towers Hill vein systems.The Brilliant vein system is hosted by undeformed tonalite and contains north-plunging oreshoots on a north-dipping main fissure and on shorter east-dripping hangingwall fissures. The Day Dawn vein system is localised along a north-dipping dyke at the contact of two deformed granitoids in a brittly reactivated mylonite, where horizontal oreshoot plunges may be related to the original megascopic undulations in that structure. The Towers Hill vein system is hosted in two granodiorite types and has multiple ore controls.Structural analysis indicates that the distribution of the oreshoots within the vein systems is variously controlled by the primary fabric and igneous contacts of the granitoid host rocks. Splaying, changes in dip, and fissure intersections are the main controls. The largest vein systems are both in reactivated shallow-dipping mylonite, or in fissures in younger undeformed granitoids. Each vein system lies in a separate structural domain, usually where older east-striking structures are preserved.

Jan 1, 1990

Traditionally, the Lead Lode at Broken Hill has been represented on presentation plans, cross sections and diagrams in scientific papers as a solid black mass, around which the more 'interesting' and 'structurally useful', wall rocks appear to wrap. Structural analysis of the Broken Hill orebodies has usually turned to these wall rocks to determine the structural history of the mineralisation.This tendency to represent the orebody as a massive single entity is incorrect and the aim of this paper is to illustrate that sulphide orebodies (in this case Lead Lode), are a dynamic part of the mine stratigraphy. They can preserve a great deal of useful structural information that can be recorded with detailed internal mapping.Three main categories of ore type are recognised in Lead Lode; Stratiform ores, Mobilised ores and Metasomatically altered ore. The ore types in these categories occupy or have formed in distinct structural and stratigraphic positions and have clearly recognisable inter-relationships.

Jan 1, 1993

The excavation of sandstone of generally medium strength for the Liverpool Link Line by Dosco Mark 2A Roadheaders has demonstrated the versatility and good performance of road- headers in suitable rock formations. A description is given of the strata traversed by the tunnels together with descriptions of equipment and crews, excavation sequences, operating difficulties and the results achiev- ed. In addition tunnel construction is des- cribed for a difficult section where there was only O.Sm clearance between invert and a four lane vehicular tunnel below, and O.5m clearance between tunnel crown and a century old sewer above.

Jan 1, 1976

By Hagen G, Uhlig H

In the Federal Republic of Germany the thermal environment in underground coal mines has deteriorated progressively over the past years. The number and capacity of refrigeration plants have increased correspondingly. In recent years high capacity spray coolers have been used in addition to conventional cooling coils.

Jan 1, 1988

By Jensen B, Ofori P, He Y, White E, Stanmore B, Brien M, O&apos

As part of a large AMIRA project, an on-line moisture meter was installed at two mine sites in Central Queensland. This project investigated the factors which control the moisture content of coarse (>0.5 mm) coal from the centrifuges used in conventional coal preparation plants. It was placed immediately after the first centrifuge to isolate the factors pertaining to one machine and its feed.The meter was found to be accurate and precise when compared with manual and mechanical sampling methods. The Grubbs estimator technique indicated that its precision is better than 0.3 per cent at the 95 per cent confidence limit.It has been identified that:1. the variability of the measured moisture contents of coarse coal can be described by normal distributions. Standard deviations of about 0.6 per cent are common; and2. the treatment of the coarse coal on the drain and rinse screens immediately prior to the centrifuge can affect the final moisture content.

Jan 1, 1995

By S Coward, J Vann, R Wolff, S Jackson, S Moayer, A Bye

Uncertainty about the future and orebody should significantly impact evaluation of mining projects. Scenario planning, widely used in other industries, for example in the petroleum industry, can provide organisations with an opportunity to explore the consequences of uncertainty on their future plans. By developing plausible scenarios, scenario planning assists decision makers by allowing them to make systematic and possibly effective decisions for the future. This paper reviews existing mine project evaluation in the context of a new framework called scenario-based project evaluation (SBPE) (Vann et al , 2012) that addresses many shortcomings of existing approaches. SBPE uses conditional simulations (CS) models as inputs which are evaluated against future alternative project pathways (æalternativesÆ). These alternatives are evaluated using multiple plausible images of the deposit (CS realisations) which capture realistic variability and as an ensemble, map uncertainty of various orebody attributes at fine scale. The alternatives can involve different mining, stockpiling, blending and processing strategies. The ultimate output is a (stochastic) set of cash flows for each alternative from which financial measures, such as NPV, can be derived. Alternatives can then be explored in the presence of against external scenarios such as changes in prices, costs, and taxation. The obvious problem with such data rich results is knowing which scenarios or group of scenarios are optimal.An innovative approach to robust stochastic optimisation (RSO) suited to the SBPE framework is presented here for the first time. This approach to RSO aims to deal with the large number of alternatives generated from SPBE. The goal of applying the RSO approach to SBPE is to identify robust strategic alternatives (project configurations) which have the flexibility to deal with variability and uncertainty of geological and processing inputs such as density, grade and process performance. By applying the proposed RSO method, it is possible to deal with uncertainty and identify the best project configuration in the face of a large number of envisaged scenarios. A case study is provided, in which we have tested the application of the proposed method and compared the result with conventional methods. An important conclusion from this research is that selecting the value of the penalty coefficients in the RSO approach proposed is (as is all optimisation) an exercise of trade-offs; a higher net present value (NPV) is generally associated with a higher risk and a lower risk is associated with a lower NPV. Indeed, this is a strong argument for considering the RSO approach outlined here over more conventional approaches.CITATION:Moayer, S, Vann, J, Coward, S, Jackson, S, Bye, A and Wolff, R, 2012. An innovative approach to robust optimisation for scenario-based mineral project evaluation, in Proceedings Project Evaluation 2012 , pp 141-148 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 24, 2012

A brief review of the problems in ventilating and cooling deep and hot Australian mines is presented. An overview is given on the development of the controlled partial recirculation concept. The main part of this paper describes the first majo

Jan 1, 1994