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By J Poniewierski, Varcos D

Efficient blasting requires constant vigilance with respect to the actual layout being used in the field. Objective measurement techniques are required in laying out a pattern as the 'by eye' or 'thumb suck' methods cannot guarantee consistent results in layout. Erratic blast results are the consequence of such an approach. In a case study at Sons of Gwalia mine, it was demonstrated that incorrect front burdens had a snowballing effect on otherwise carefully laid out blasts, resulting in both excessive amounts of boulders caused by preconditioning of bench fronts and tops, and tight digging. Both problems caused lower excavator productivity and excessive excavator damage, as well as making it difficult to set out subsequent blasts correctly. Several field measurement methods are available to aid in determining correct blast layouts and one is described in this paper.

Jan 1, 1994

By D R Quick

The Goodall gold mine is located 30 km east of Adelaide River, within the Pine Creek 1:250 000 map sheet, at 8 525 000 mN: 750 000 mE, on the AMG grid. The first gold was poured in April 1988 and the mine closed in September 1993, having produced 228 400 ounces of gold from 4.095 million tons of ore, at a head grade of 1.99 g/t. Oxide and primary ore was mined from one large open cut and low grade oxide ore from three smaller pits. The gold mineralisation was discovered in 1981 by means of a helicopter borne rock chip sampling survey, which delineated 13 discrete anomalies. Systematic grid sampling of rock chips outlined an area of 1300 m by 300 m within the 2.0 g/t contour. Over 7500 m of costeaning was used to delineate the A and B-Pod mineralised areas. Geochemical soil sampling played only a minor role in the discovery and geophysics none at all. By the end of 1984, 40 diamond drill holes had been completed and a resource of 3.63 million tonnes at 3.0 g/t calculated. In January 1985, Western Mining Corporation Ltd became a joint venture partner and funded exploration to cam a 60 per cent interest. Additional drilling led to a feasibility study in 1987, based on a Measured and Indicated resource of 4.25 million tonnes at a grade of 2.35 g/t. The host rocks are quartzo-feldspathic wacke and interbedded phyllitic siltstone, of the Proterozoic Burrell Creek formation. The main zone of gold mineralisation, A-Pod, occurs in a sub-vertical vein array, up to 50 m wide and 800 m in length, of quartz and sulphide veins (5-20 mm wide), It is parallel to and on the east limb of an upright, north plunging anticline. Five types of veining have been recognised, with the bulk of the gold mineralisation associated with quartz-pyrite-arsenopyrite and chlorite-quartz-pyrite veins. The gold occurs as particles, from 1-20 micron, as inclusions and along fractures in pyrite and arsenopyrite and to a limited extent in chlorite. The mineralisation is epigenetic and structurally controlled by fractures developed during an earlier folding event. The gold is assumed to have been derived from the underlying sediments of the Koolpin Formation by hydrothermal fluids emanating from the deep seated northern margin of the Cullen Batholith. Precipitation of gold may have been controlled by variations in temperature and pressure.

Jan 1, 1994

By B Maybee, L Fava, D Millar

In the context of a case study for an underground gold mine, the value generated by a schedule optimisation tool (SOT) is assessed. SOT is a software tool for underground mine planning that maximises the net present value (NPV) of a development and production schedule. A baseline study measures the NPV of a schedule generated by SOT from a sequence prepared by the site mine planners. Operational resource constraints and precedence constraints are adhered to by the schedule and NPV is evaluated with a financial model including revenues, costs and discount rate, as specified by the mine planner.The case study has several facets in addition to the baselining component. Scenarios were conducted that examined the degree of constraint on operational resources, the projected gold price and unit costs. Life-of-mine schedules subject to optimisation using SOT allowed for equitable comparisons.Haulage was identified as a dominant constraint for the mine. It was one of six operational resources that were used to constrain the optimisation of the mine schedule, with alternative levels for some of these constraints being identified so that their effects on the NPV could be studied. Alternative price projections for gold and different cost projections were identified and their effects on the optimised schedule examined. Price and cost scenarios that brought additional economic material into the schedule at various times in the mine life were considered in comparison to a scenario that assumed no additional economic material would become available.This case study illustrated that the use of a schedule optimisation tool to optimise mine schedules provides mine planners with an ability to perform a wide variety of analyses in a relatively short period of time. Such tools thereby support strategic decision-making that can add significant value to an orebody.The case study demonstrates that by fixing the set of development and production activities to be carried out before optimising the life-of-mine schedule, the mine planners can inadvertently set up a situation where the NPV would be progressively eroded in the last several years of the mine life. This clearly illustrates the need for schedule optimisation to be integrated with life-of-mine planning.CITATION:Fava, L, Maybee, B and Millar, D, 2012. Decision support for an underground gold mining operation - A case study using the schedule optimisation tool, in Proceedings Project Evaluation 2012 , pp 41-48 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 24, 2012

By Griffin PT, Espinosa-Gomez R, Jameson GJ

Two major issues are to be addressed in the Copper Concentrator of Mount Isa Mines Limited. The first of these is the need to increase concentrator flotation capacity to increase copper recovery, while the second is the need to reduce the iron sulphide dilution to meet future smelting requirements. Extra capacity in the cleaner and retreatment sections of the concentrator have been identified as key target areas, with additional copper recovery of at least one per cent identified from plant trials. Extensive pilot plant tests have been undertaken to evaluate the performance of the Jameson cell compared to conventional mechanical cell and column circuits. This work has shown that Jameson cells present an opportunity to achieve the desired grade and capacity specifications at lower capital cost than available alternatives. This paper outlines metallurgical results of work undertaken in the Copper Concentrator, together with a summary of pertinent Jameson cell operating parameters investigated during the period.

Jan 1, 1993

By V Rimal, d M. Tangstad

Multiphase slags form the basis of the reduction pathway for manganese ferroalloy production. The present work aims to understand the flow of slag through the coke bed based on experimentation in controlled conditions. Synthetic slags of different basicities were evaluated for their phase composition, viscosity, and flow. The two-phase slag will have two zones: a liquid slag zone and a multiphase zone. The multiphase zone will consist mostly of a solid phase with some liquid slag between the solid particles. The multiphase part will hence have a high viscosity. The liquid zone will flow into the coke bed while the multiphase area will stay. With increasing reduction, the multiphase area will decrease in size until the solid phase is gone and the whole slag will flow into the coke bed. The effective viscosity of slag will decrease with the lowering of the solid oxide phase. The results from flow experiments confirmed that the segregation of phases occurs when slag flows through the coke bed. It is observed that the flow is dependent both on the size of the void and the viscosity of slag.

Aug 21, 2024

By Landy D. M, Ward M. O, Power W. L

Geological structures are irregular and intricate, so creating a 31) solid geology model is a complicated process. A software system can only partially automate this process, since geological knowledge and experience are required. Therefore, the interaction of a geologist is critical for such a system. This paper discusses some useful advanced functions for enhancing the visualisation and manipulation of 3D solid geology models: flexible attribute display, multiple views, auxiliary display objects, and geologically sensitive operations. It also describes some experiments to explore the effectiveness of these functions and presents sample output. Most existing 3D solid geology modelling systems are implemented in an ad hoc way, which greatly reduces their reusability and extensibility. This paper presents a generic framework for 3D solid geology modelling systems, which is based on object-oriented technology. The deficiencies of current systems may be improved by using this generic framework. A modelling process based on drillhole data is discusses as a case study.

Jan 1, 1995

By R Neivandt, Kane, M O&apos, D Browne

Newmont Australia is the operator of the Mt Leyshon mine near Charters Towers, Queensland. Mt Leyshon is an open cut gold mine, which processed on average 5.0 Mt of ore and produced up to 250 000 ounces of gold per year. Mining was completed in early-2001, followed by treatment of low-grade ore stockpiles for a further 12 months. Approximately 250 ha of waste rock dumps have been rehabilitated. Rehabilitation of two of the three tailings storage facilities (TSF) has been completed and the third is in progress. A field performance monitoring system that includes an automated meteorological station, large-scale lysimeters (measurement of net percolation), and in situ moisture content sensors (measurement of moisture storage changes in the cover material) were installed to monitoring performance of the cover systems placed on the waste storage facilities. This paper focuses on the installation and calibration of the in situ moisture monitoring system. The moisture monitoring system provides automated detailed in situ volumetric water content data above and within the large-scale lysimeters. A portable unit that provides spatial in situ moisture content measurements at additional locations on the cover system is also utilised. The paper will focus on installation and calibration of the in situ water content monitoring instrument in the waste rock, coarse cover material, and fine textured cover materials of the tailings facility and waste rock dump cover systems.

Jan 1, 2003

By Hill J. R M, McDonald M. M

A prediction technique for support perfor- mance of hydraulic backfill in narrow stopes is applied to two stopes separated vertically by a sill pillar. Predicted stope wall closures and fill pressures compare favorably with field measurements taken over a period of several years at two mines in the Coeur d'Alene dis- trict. Stope wall closure and peak pillar stress can be substantially reduced by improved fill quality within a practicable range of fill and rock properties.

Jan 1, 1973

By Ellery B. I

Field investigations recently undertaken by Utah Development Company (U.D.C.) have been developed to allow the assessment of ground conditions relevant to the use of large bucket wheel excavators for pre-stripping overburden. "Bucketwheel diggability" predictions were made on the basis of a wedge test which was perform- -ed in the field on nominal 150 mm diameter drill core samples. Specific separation force (calculated from the wedge test results) for different rock horizons were theoretically related to the excavation rates of various sized bucketwheels, i.e., "bucketwheel diggability". The specific separation force was shown to vary with lithology, structure, weathering and moisture changes. By correlating these features between boreholes, an overall assessment of bucketwheel diggability was then made. The approach adopted to assess bucket- wheel diggability incorporated various levels of investigation. Initially, a reconnaissance stage provided information from widely spaced 150 mm cored holes to compare and contrast areas with differing bucketwheel digging char- -acteristics. The following stages progressive -ly added to this information, until finally, between hole correlations, allowed calculations to be made of volumes of materials of similar

Jan 1, 1981

Many block caving operations experience difficulties during undercutting, resulting in draw horizon damage, production loss and extensive drift repairs for the life of the block cave. This paper deals specifically with block cave undercut aims strategies, methodologies and management to avoid the problems indicated above.

Jan 1, 2000

By Takiuchi T, Kurita M, Owada S

This paper describes the possibility of the application of flotation to the separation of monazite from xenotime and of columbite from ferberite, which have been said to be difficult with generally used physical beneficiation methods. For Malaysian monazite and xenotime samples, a great difference is observed between the flotation recoveries at pH 7.5 using 1.0 x 10-4mol/1 dodecylammonium chloride (DAC). The grade and recovery of columbite in the binary flotation with both minerals result in 85 per cent and 67 per cent in the cleaning froth and 91 per cent and 51 per cent in the re-cleaning froth, without adding any scavenging stages. For monazite samples from various localities, the flotability is dominated by the electrostatic interaction between mineral surface and collector ion using DAC as collector, but the singular decrease of flotation is observed in the sample of which the crystallinity is low and the surface structure is rugged and complex. Otherwise, ferric ion in the flotation system probably dissolved from mineral is found to activate the flotation using sodium dodecylsulfate as collector. For columbite and ferberite, the separation is judged possible at pH 3.0 using 1.0 x 10'3mo1/l sodium oleate (NaOl) from the single flotation results of each mineral. In the binary flotation, however, columbite recovery in the froth is greatly diminished below that expected. This would be because NaOl is prevented from adsorbing on the columbite surface of which the charge is transformed more negative side by the specific adsorption of the tungstate ion dissolved from ferberite.

Jan 1, 1993

The effects of detonation of downlines and downline-booster systems on lodse-poured charges of 94% porous prilled ammonium nitrate/6% fuel oil (AN/FO) were determined. Detonation stability was indicated by the initiation-failure pattern of detonating fuse witness lines located at intervals along the charge. Steel tubing was used as the confining medium. Charge diameters (d) varied between 2-21/32 and 8.1/8 in. and specific charge weights (w) of downlines between 4.0 and 93.2gr/ft. The axes of charge and downline were colinear. The minimum value of w required to cause initiation of AN/FO increased with d. When initiated by a downline only, the charge'underwentlowòorder detonation. When downline-booster systems are used, the detonation wave in the downline cuts all equatorial planes in the charge before the detonation wave in the surrounding AN/FO. If the downline itself does not cause initiation, therefore, the explosive ahead of the main detonation wave is crushed, and hence desensitised, by the radially-expanding compression wave and gases generated by the downline. In a given equatorial plane, the fraction gftharge undergoing detonation decreases with an increase in the booster-plane distance. The longitudinal limit of nation increases significantly with d, but surprisingly little with a decrease in w. In the presence of a downline, the blasting performance of AN/FO charged _

Jan 1, 1970

By J Miedecke

A metalliferous mine has operated at Storys Creek from the 1890s to 1979. Storys Creek drains from a pristine catchment and National Park and remains as the most degraded stream from historic mining in north-eastern Tasmania. It has been the subject of public concern since the closure, particularly at times of high rainfall such as existed in 1985 and 1986. The mine is located on the banks of the creek, which flows into a major river, the South Esk River, which is one of TasmaniaÆs largest rivers and important for recreational fishing and water supplies. For much of the life of the of the operations tailings were directly discharged into the creek, and in latter years stockpiled or very close to it. Little rehabilitation was carried out at mine closure. The result was erosion and subsequent deposition on the banks of the creek downstream. Direct emissions of adit water and the consequential emission of contaminated ground water to the creek continue to affect water quality. Contaminant loads discharging from the mine and tailings comprise 70% of the metal load in the catchment and are by far the largest single source. Acidity data suggested that the introduction of systems to introduce alkalinity could be effective in ameliorating the residual acid drainage impacts in the Storys Creek catchment. After a period of investigations and trials which proved their effectiveness, treatments adopted have included the following: relocation of tailings to a constructed and clay capped disposal area and rehabilitation of tailings area; crushed limestone addition to stream flows; crushed limestone addition to creek banks and exposed tailings; sealing of a drainage Adit; and construction of an anoxic drain to generate alkalinity to surface waters draining to old mine workings. These innovative treatments have resulted in a marked improvement in water quality draining from the area. The anoxic drain is believed to be one of the few, if any, which has been constructed to have generated high levels of alkalinity from clean waters and offers a solution to the clogging problems experienced in such drains in the past. Similarly, the use of crushed limestone in an active stream has proved effective in buffering acid drainage and removing metals from solution.

Jan 1, 2003

By Mizuta T, Sakurai M

The Pine Creek Inlier produced 12 440 kg of gold in the period from the first gold discovery in the 1860s to the early-1900s. During the 1930s renewed large-scale prospecting took place and gave a foothold for today's gold mining operations. The rise of the gold price and improved mining methods in the 1970s and 1980s made possible low cost, bulk low grade mining operations. Various gold deposits including vein, network and stratiform types occur in the Pine Creek Inlier (Nicholson and Eupene, 1990). The Tom's Gully deposit is located 100 km south-east of Darwin in the Northern Territory. It is hosted in the early Proterozoic Wildman Siltstone and lies north-east of 1800 my old Mt Bundey Pluton (Figure 1). Around the Mt Bundey Pluton, there are several prospective base and precious metal deposits such as Quest 29. The Tom's Gully gold deposit was discovered in 1986 and yielded a total of 3070 kg of gold from ore averaging 9.35 g/t gold between 1987 and 1990 when the mining operation was terminated.

Jan 1, 1994

By Kuipers A. J

Aberfoyle has been applying computer methods to mine geology in small to medium-sized underground mines since the early 1980's. Recently, the installation of DATAMINE software at the Hellyer Mine in Tasmania has allowed development of computerised applications which assist both mine geologists and mine planning engineers on a daily basis.Comprehensive data is entered into a database prior to survey coordinating to produce a processed database which can be accessed for construction of a variety of plots. The folded and faulted nature of the orebody contacts at Hellyer has necessitated the use of the structure contour method to provide a complete 3-D spatial interpretation. Computer-generated contact intersection points are hand-contoured before digitising and wireframing as a digital terrain model. This wireframe model can be sectioned in any plane for mine planning.

Jan 1, 1990

By Trueman R

If continuous mining systems are to be successfully applied in metalliferous mines then reliable models will be needed to predict rock cutting machine advance and tool wear rates for effective machine selection before mining commences. Many of the predictive models developed to assess cuttability in situ are over-simplistic. As a result they tend to be both site and/or machine specific. Nevertheless very detailed models have been developed for full face machines which are capable of accurate cuttability predictions in a variety of rock mass conditions and for a variety of machine and tool configurations. However, models to predict productivity and tool consumption for partial face machines are not as well advanced. There is a need to develop reliable models for partial face machines such as Roadheaders, the Robbins Mobile Miner and the HDRK-Wirth CMM, as these types of machine are likely to predominate in a mining environment. The paper outlines the current state-of-the-art for predicting cutting machine performance and the work being carried out within the Centre for Mining Technology and Equipment (CMTE), in collaboration with the Australian mining industry, to advance our capability in this area.

Jan 1, 1995

By K Saito, M Hasegawa

Removing sulfur and phosphorus from molten iron can be expressed by the following reactions, respectively. [S]Fe + (O2-)slag = (S2-)slag + [O]Fe [P]Fe + (3/2) (O2-)slag + (5/2) (FeO)slag = (PO43-)slag + (5/2) Fe(liquid) These equations indicate that desulfurisation and dephosphorisation have opposite oxygen potential conditions. If a small amount of desulfurisation slag not removed is carried over to dephosphorisation process, the reaction of sulfur mentioned above proceeds toward left hand resulting in increasing sulfur content in molten iron. For better understanding of such re-sulfurisation reaction in hot metal pre-treatments, the present study aimed at evaluating the effect of iron oxide on the sulfur distribution ratio between slag and hot metal. To measure sulfide capacities and FeO activities simultaneously at temperatures below the melting point of pure iron, CaO-SiO2-FeO and CaO-Al2O3-FeO ternary molten slags were brought into equilibria with copper-iron-sulfur liquid alloys, and the equilibrium oxygen partial pressures were determined with an electrochemical technique involving the stabilised zirconia solid electrolyte. The experimental results showed that the sulfide capacity increased with an increase in FeO content, and this trend was consistent with the fact that FeO was basic. Although the addition of FeO raised the FeO activity and oxygen potential, the calculated value for sulfur distribution ratio between slag and hot metal increased with increasing FeO content.

Jun 19, 2024

By N Mangadoddy, P Jampana, S Diddi

The study of air-core dynamics in hydrocyclone operation is essential for predicting separation efficiency in mineral processing. Electrical resistance tomography (ERT) allows non-invasive measurements of hydrocyclone internal flow dynamics. Existing regularisation methods such as Gauss-Newton and TV norms rely on optimisation techniques which have very high computational cost for very fine meshes. In contrast, the monotonicity method has much lower computational cost as it does not solve such minimisation problems. In this paper, results from the monotonicity method, Gauss-Newton (GN) (Tikhonov) and Total-Variation (TV) norm-based minimisation methods for estimating the air-core diameter in hydrocyclones are compared. We study these methods on the laboratory hydrocyclone experimental two-phase flow data. The results obtained are validated against High-speed video (HSV) imaging and Computational Fluid Dynamics (CFD) results. The results on different mesh sizes, in particular for very fine meshes with the number of cells ranging from 30 000 to above 100 000 are also investigated. The data used in this study is obtained from ITS Z8000 ERT system. This system does not measure the voltages on the current carrying electrodes. Since these voltage values are required for the monotonicity method, we implement an interpolation method to compute them. The results show that the monotonicity method provides a closer approximation of the interface between air and the water phases.

Aug 24, 2022

A survey of leaching systems for the dissolution of gold has been undertaken and their advantages and disadvantages evaluated both from their effectiveness at leaching and their compatibility with carbon- in-pulp (CIP) and resin-in-pulp recovery. In the near future it is almost certain that cyanidation in some form will remain the leaching system of.choice although economic and environmental pressures could see the introduction of other leaching systems particularly for treating refractory gold ores. The most likely alternative leaching systems appear to be acid chlorine, acid thiourea and ammoniacal thiosulphate. INTRODUCTION High grade reserves of readily recoverable gold ores are gradually being depleted which, inevitably, must create a greater awareness amongst gold producers, of the efficiency and, in some cases, the suitability of present day metallurgical processes for treating low grade, complex and refractory deposits. One of the key steps in the extraction of gold is the dissolution of the metal using chemical reagents which, ideally, should be cheap or recyclable, selective, non-toxic and compatible with down-stream recovery processes. In practice, meeting all these critera is difficult - if not impossible - particularly in view of the stringent environmental impact requirements which must be met Nowadays.

Jan 1, 1982

By Ho D, Yang J

The ready availability of powerful desktop workstations, which combine 3D real-time graphics and processing speed better than that of supercomputers of a few years ago, now allows the cost-effective solution of real world geomechanics and underground mining strength simulations. The inclusion of geotechnical factors such as rock joints and porous flow on strength and stability are discussed together with the range of available deformation and failure models for soil, rock and concrete. This paper describes the capabilities provided by finite element graphics and analysis software for modelling and sequential investigation of both excavation and lining, or rock bolting, construction sequences. Examples of the use of finite element models in mining are also included in the paper, together with a discussion of the required people, software and computer hardware resources required to achieve timely and productive results.

Jan 1, 1995