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By K McSweeney, A Marton

This paper discusses the development of a strategy for ensuring long-term geotechnical stability of final pit walls at AngloGold AustraliaÆs Sunrise Dam Gold Mine. The strategy makes use of improved blasting techniques, changes to the mining sequence and other geotechnical techniques. Only the blasting techniques will be discussed in this paper. These were developed from numerous trials over a period of several months from May 2003 through to November 2003. The focus was to reduce crest loss damage and thereby improve final wall integrity, maintain designed safe berm widths, and ensure long-term stability. Crest loss mechanisms are now understood and are explained in this paper. The preferred solution is outlined; which is a combination of improved blasting and changes in the mining sequence to cater for pre-existing ground conditions. These ground conditions include dynamic hyper saline water with sometimes intersecting steeply dipping discrete structures. Project requirements were defined as mitigating or eliminating crest loss using 127 mm diameter pre-splitting and targeting minimal production blasting vibration levels against the walls. Blast results were measured by post blast visual inspections and video. Blast design input utilised the predictive algorithms built into simulation software when attempting to minimise vibration levels against the walls. Protection of the already fired pre-split line is now achieved using small charges against the wall and timing sequences which form a mask for the later firing main charges. The pre-split spacing is now modified to suit the geology. There eight blast domains identified around the perimeter of the pit, each having varying joint orientation. In addition, blasting the bench adjacent to the berm crest has particular considerations not required by the middle and lower benches. The preferred solution was to purposefully translate this damaged top section of the pre-split bench into a planned subsequent dig zone. The design of this top æweightÆ is a direct response to the nature of the crest loss mechanism.

Jan 1, 2004

Safety and health at work is about people. It is about people who plan for work, organise work and perform work. It is about those who come in contact with the workplace and those who are responsible for the workplace. There are wider ranging safety and health obligations that are imposed on the industry stakeholders that span all phases of the production process. In all cases, those responsible for discharging the obligations must ask the questions: Is what we propose safe?, can it be done safer? and are we sure? What we learn from recent legal cases before the courts is that it is essential that all stakeholders work together in a collaborative way when discharging these obligations. Safety and health at work cannot become an issue that is viewed only through the eyes of a single stakeholder group. The reason for this is quite simple. The interrelatedness of the responsibilities that are imposed on each of the stakeholder groups, means that the performance based legislation simply wont work, where an active model of communication and consultation is not in place.

Jan 1, 2005

By G J JAMESON

The flotation cell has undergone a number of changes since the process was first introduced in Broken Hill in the early years of this century. The development of the mechanical flotation cell is reviewed, followed by a discussion of more recent developments such as the flotation column, the air-sparged hydrocyclone, the Wemco-Leeds cell, the Bahr and Deister columns and the Jameson cell.

Jan 1, 1992

By G Harbort, K Quan

Traditional engineering practice for concentrator design uses a mixture of risk minimisation options and capital minimisation approaches. Often this is based on the preferences and experiences of the engineers involved.A geometallurgical approach involves identifying primary lithology, alteration, and mineral dispersion patterns within a deposit to allow representative samples for test programs. This provides a method to infer from laboratory test results meaningful production data for larger amounts of the ore body. Geometallurgical models can be integrated into the resource block model and subsequent mine plan and can assist in predicting when difficulties in the processing route might be expected, allow adjustment of the design to compensate for these or provide an early warning system so that production forecasts can be more adequately developed. Simulation modelling is the process of creating a computer model of a real system based on mathematical logic. In simulated time, the model explores the randomness and chronological sequencing of events observed on real systems. The objective is to mimic the real system with sufficient accuracy to make predictions of real behaviour under experimental conditions. Amec Foster Wheeler often use the ‘discrete-event’ simulation modelling technique. This method is well suited for inclusion of the statistical variation of effects in unit operation, mechanical availability, throughput and operating strategy (based on historical operating data for equipment downtime), operating schedules and equipment capacity. The net result of the simulation model is an analysis that can quantify risks in terms of system performance and capital and operating costs.CITATION:Harbort, G and Quan, K, 2017. Concentrator design – standard engineering practice versus geometallurgy and simulation, in Proceedings MetPlant 2017, pp 195–206 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

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 T Baumgartl, B Richards

Covers on waste rock and tailings remain the primary choice for closure planning where the purpose is to create an environment where water ingress into reactive material can be controlled and/or prevented. In semi-arid and arid environments, dry cover systems are the preferred option with the design intention to absorb rainfall and to prevent deep drainage. Although the average amount of rain typical for semi-arid environments is relatively low and evaporative demand is high, the seasonal and annual distribution may vary greatly. Rocky substrates are often the only choice for the construction of covers due to economic constraints or availability of suitable materials. While the water holding capacity may be suitable for the application of a dry cover design in arid and semi-arid climates, some of these covers bear the risk of preferential water flow when rain events are intensive or occurring at high frequency. The objective of this presentation is to demonstrate the occurrence of preferential flow through rock containing dry cover systems. A regional classification for the applicability of dry covers is attempted to delineate those regions of Australia where the characteristic of the rainfall pattern increases the risk of failure for dry cover designs. CITATION:Baumgartl, T and Richards, B, 2016. Rainfall patterns rather than climate classification control cover design for closure, in Proceedings Life-of-Mine 2016 Conference, pp 89–92 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

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 Tumilty JA, Douglas WD

With a view to characterising activated carbons with respect to their ability to adsorb gold from cyanide solutions, an attempt was made to establish correlations between the equilibrium capacity constant of the activated carbon for gold (k value) and five other parameters. These parameters were percentage ash content, iodine number, methylene blue value, surface area, and pH respectively. Twenty four different proprietary brand activated carbon products were examined, the correlations being established by means of linear regression analysis. It was shown that a significant correlation only existed between k and pH value. This was interpreted in terms of the presence of oxide complexes on the activated carbon surface. Further test specifications as developed at the Anglo American Research Laboratories are also outlined with a view to the selection of activated carbons suitable for use in' a carbon-in-pulp operation. Methods for assessing both the capacity and the kinetic response of carbons for gold adsorption are presented, while the measurement of attrition resistance, particle size distribution and moisture and solubles content is also outlined. The measurement of the capacity constant for gold adsorption together with attrition resistance are considered to be necessary in the initial selection of a suitable carbon.

Jan 1, 1982

By Y Peng, C Burns, Y Mu, R A. Lauten

In both laboratory flotation experiments and from analysing the composition of the lead concentrate at the Boliden Tara lead-zinc mine in Ireland, it has been found that F-250 may replace cyanide as a pyrite depressant. Replacement or reduction of the cyanide consumption is highly desirable from a safety perspective given the toxicity of cyanide. Scrutiny of results from the plant trial indicate that F-250 is less efficient as a cyanide depressant when the flotation feed contains high levels of pyrite. Statistical analysis of the results does not capture this trend, illustrating a need to collect more data at higher pyrite ore levels. A recent model proposed for biopolymer-induced pyrite depression is reviewed and discussed next to the suggested mechanism for pyrite depression via cyanide. Review of the interactions causing pyrite depression point to different manners in achieving depression. In light of the less efficient F-250 pyrite depression at high pyrite levels, it is speculated if the two depressants may act synergistically at high levels of pyrite in the feed. CITATION:Lauten, R A, Burns, C, Mu, Y and Peng, Y, 2018. Pyrite depression at Boliden Tara using F-250 – a biopolymer, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 385–392 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By N Power, A D. Costar

There has been significant growth in mining and energy exploration in South Australia, which has identified new major potential opportunities. This sector generates significant economic value to the state and their support remains a priority for the state government. The delivery of this economic and associated community value to the state is dependent on the mining and energy sector being able to access reliable water supplies.The vast majority of priority areas for the mining and energy sectors are located in areas that have traditionally been of low priority from a water-use perspective and hence, data and knowledge levels are generally low.Recent studies have identified a potential increase in demand for water in the mining and energy sector for potential developments from approximately 40 GL to over 170 GL over the next ten years. The studies found that water and water infrastructure is the second highest proportion of planned infrastructure capital investment by resource companies. The South Australian GovernmentÆs Plan for Accelerating Exploration (PACE) initiative (PACE 2020), also identifies addressing the issues of location, use and management of South AustraliaÆs water resources as a key priority for the growth of the mining and energy sector.The Department of Environment, Water and Natural Resources (DEWNR) has developed the facilitating long-term outback water solution (FLOWS) initiative. DEWNR is currently undertaking a suite of programs to provide groundwater information at the regional scale to better target water supply options for mining and energy developments and community water supplies.The Goyder Institute for Water Research has leveraged significant research investment of $3 M to develop methodologies to interpret airborne geophysics to map groundwater sources.The FLOWS Initiative will provide key content for the PACE Water Program and will also assist in the development of water supplies for remote far north communities by identifying alternate groundwater sources to improve water supply security.This paper will discuss how developing an appropriate science and knowledge base will encourage and secure development where appropriate, enable prudent decision-making and policies regarding water allocation, accounting and licensing, whilst ensuring the protection of environmental assets.CITATION:Power, N and Costar, A D, 2013. Finding long-term outback water solutions, in Proceedings Water in Mining 2013 , pp 191-196 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

By R M. Yanamandra, M Kumar, S K. Tripathy, N Mangadoddy, P Sudikondala

Spiral concentrators are one of the flowing film gravity concentration devices used to beneficiate coal and mineral ores. The aim of the current study is to understand the particulate flow and separation performance of an LD9 spiral concentrator using a multi-phase Computational Fluid Dynamics (CFD) model. The CFD model utilises the Algebraic slip mixture model to simulate particulate flows. The model employs the Renormalisation group (RNG) k-ɛ turbulence models to resolve the fluid turbulence. Initially, the volume of fluid method was adopted to track the water-air interface. Simulations were then carried out at low (0.3 and 3 wt.%) and moderate (15 wt.%) solids concentrations. Multiple particle-phase representing particles of poly sizes (75–1400 µm) and multi-densities (1450–2650 kg/m3 ) were simulated to study the particle segregation on the spiral trough surface. The numerical predictions are compared with the literature performance data at a diluted pulp flow rate of 6 m3 /hr. The results were found in close agreement. Further, the same CFD model is used to study the change in pulp velocity, streamflow rates, and separation performance at increasing solids concentration. For the same density particles, Fine particles mostly show higher volume concentration in the middle and outer trough regions, whereas coarse particles show higher volume concentration in the interior and central trough regions. It implies that the fine particles mostly segregate towards the outer region, and dense particles segregate towards the axial column.

Aug 24, 2022

By Ryan CG, Cousens DR, Griffin WL

The proton microprobe is developing into a vital tool in the geosciences, through its high sensitivity for in-situ detection of trace elements in the ppm regime. This paper will describe the instrument at the CSIRO Heavy Ion Analytical Facility at North Ryde, including features crucial to its successful application in the geoscience. Examples of applications in the basic geoscience and mineral industry related research are described briefly. Conditions required for widescale applications in the minerals industry are Discussed.

Jan 1, 1989

By Nilsson C

Man has always been and will always be part of his environment, in ,a good, bad or indifferent manner. Until quite recently, this environment has been the atmospheric boundary layer above the land masses, and to a limited extent the air-sea interface of the oceans. Since the days when he lived in caves, he has built up a wealth of observations on these two environments,-with ever-increasing scientific precision which unfortunately until quite recently was completely insufficient for modern capabilities of data analysis. Consequently, in a sense, he has left in his wake thousands of years of missed, opportunities for making exact observations and increasing his understanding. The data of the past are lost and he has to be satisfied with what he can assemble from now on when his environ- ment, largely as a result of his actions, is exhibiting more and more rapid variations in time; in other words, time series of observations of phenomena are required, the length of which is critical for most purposes of analysis.

Jan 1, 1970

By C G. Ryan, D R. Cooke

The Thames gold-silver deposits are part of the Hauraki goldfield, situated within the Miocene to Pliocene calc-alkaline Coromandel Volcanic Zone (CVZ). The Waitangi vein system is one of the mineralised ore shoots in the Thames district. The Thames gold deposits are characterised by shallow-level epithermal vein mineralisation with phyllic to advanced argillic alteration assemblages and abundant sulphide minerals including pyrite, arsenopyrite, chalcopyrite, galena and sphalerite. Gold occurs as electrum in association with sulphide minerals. Sulphur isotope analyses of mixed sphalerite-galena and sphalerite-galena-chalcopyrite samples yield a narrow range of δ34 SCDT values (-1.0 to 0.9 ë; n=5), whereas late spongy pyrite gives unusually light sulphur isotope values (-16.7 to -27.9 ë; n=4). Vein quartz from the mineralised zone at Waitangi yields δ18OSMOW values from 6.8 to 12.7 ë (n=23). Fluid inclusion studies indicate a homogenisation temperature range of 190¦ - 296¦C and salinity range of 0.2 - 3.0 wt per cent NaCl equivalent. Similar temperature and salinity ranges have been recorded for the other gold deposits in the Coromandel Peninsula. PIXE (Proton Induced X-ray Emission) analysis revealed that the Waitangi ore fluids have 1090 - 2700 ppm K (average 1600), 145 - 205 ppm Ca (average 180), 80 - 100 ppm Mn (average 90), and 80 - 200 ppm Fe (average 120) but no detectable Cu, Zn, Br, Rb, Sr, Pb and Bi (only one fluid inclusion contains 28 ppm Zn). The sulphur isotopic values of base metal sulphides from Waitangi suggest that the sulphur was derived from a magmatic source (either directly, or by leaching of igneous sulphides). The calculated oxygen isotopic composition of ore fluids is between -2.1 to 3.8 ë at 250¦C and -0.1 - 5.8 ë at 300¦C. Oxygen isotope analyses have revealed significant variations in δ18O values with elevation and gold grades. Zones of gold enrichment coincide with a zone of variable oxygen isotope values at the top of the vein system, where boiling and/or fluid mixing most likely occurred. Mixing of ore fluids with convective ground water is a likely mechanism for gold deposition in a shallow environment for the Waitangi vein system and there is also lack of fluid inclusion evidence (eg liquid-rich and vapour-rich inclusions in the same growth zone) for boiling of ore fluids. Oxygen isotope values varying with gold grades within the Waitangi conduits suggest that δ18O values may be useful in targeting bonanza grade gold mineralisation in epithermal vein systems.

Jan 1, 1999

By Hocking G

For some underground structures, the use of the plane strain assumption in stress analyses may not be justified. The finite element method and photoelasticity have been used to obtain complete 3-D solutions, but, for various reasons, neither method has found universal use. The boundary integral equation method (B.I.E.M.) can be more efficient and economical than the finite element method for 3-D problems involving large volume to surface area ratios. A B.I.E.M. program developed for calculating stresses and deformations in infinite elastic media has been used to determine the 3-D distributions of stress around T- and Y- junctions of circular tunnels in stress fields in which the ratios of horizontal to vertical stress are 0, 0.33, 1.0 and 2.0. For the T- junction considered,stress concentrations at the intersection are approximately twice the plane strain values. Except where horizontal field stresses are high, the stresses in both tunnels approximate the plane strain values at about two tunnel diameters from the point of intersection of the tunnel centre lines. The stresses in the two branches reach those for the corresponding plane strain, two parallel tunnel case two diameters from the point of intersection of thq inner tunnel walls. Very high stress concentra- tions occur in the pillar of rock between the inner tunnel walls near the point of intersection.

Jan 1, 1976

By Fawcett M

Pine Creek Goldfields Limited (PCG) is rehabilitating the Enterprise Pit to an aquatic habitat and potential water resource. This paper discusses the development and implementation of that plan. Pine Creek Goldfields Ltd's Enterprise Mine is located approximately 230 km south of Darwin. Open cut mining of the orebody commenced in 1985 and continued for eight years with 14 million m3 of ore and overburden extracted. Geochemical testing of exposed rock types in the pit has demonstrated a propensity to produce acid, and dissolved metals. A plan of management has been developed and implemented to minimise the risk of acid formation and improve the overall water quality in the final void. In developing the plan prime consideration was given to reducing the potential for pit water to impact upon the regional groundwater. An interception system was constructed on Pine Creek to divert approximately 9 km2 of upper catchment into the northern end of the Pit. Construction of the diversion system was completed in December 1993 and a comprehensive surface and groundwater monitoring program initiated. The monitoring program and associated studies are also discussed.

Jan 1, 1994

By Dyne GD

From experience in the design and operation of power station combustion facilities in most mainland Australian States, involving a wide range of black coals and lignites, and in the specification and procurement of coal supplies for power station use, techniques for the optimisation of coal resource development and power generation utilisation have been developed to ensure compatibility between characteristics of the selected coals and power station design. These techniques include computer data bases for resource data handling and computer simulation of coal-fired boilers for determining coal property cost effects. Data Base Systems allow results of coal analyses to be efficiently handled, to assist in the review of the relevance of resource data to the coal sections proposed to be mined and the coal fractions proposed to be marketed. Data Base Systems also facilitate the marshalling of coal quality data into basic utilisation format to enable a proper utilisation review and analysis of the certainty and scatter of coal properties. Computer simulation of the effects of different coal properties on the capital and operating cost of power stations is achieved by establishing conceptual design parameters of the major items of plant to relate the variations in coal specification to equipment size and type. Variations in power station budget costs can then be determined using the computer model for variations in coal specification.

Jan 1, 1983

By I Jabouri

There are many physical factors that can affect the self-heating rate of coal. The presence of seam gas has often been referred to as inhibiting coal self-heating due to the limited access of oxidation sites created by the presence of the gas adsorbed on the coal pores. Similarly, the presence of bed moisture in the coal also acts as an inhibitor of oxidation by blocking access of air into the pores. Gas drainage of a coal seam prior to mining removes both gas and moisture from the seam. Bulk coal self-heating tests in a two-metre column on both gassy, as-mined and gas-drained, dried high volatile bituminous coal show that removal of gas and moisture from the coal accelerates the rate of self-heating to thermal runaway from 8.5 days to 4.25 days, from a start temperature of 30¦C, with an airflow of 0.25 L/min. The corresponding gas evolution pattern for each of these situations is different. Therefore, it is necessary to take this change in coal condition into consideration when developing a spontaneous combustion management plan.

Jan 1, 2005

By D T. Feinstein, M B. Gotkowitz

In Wisconsin, state laws and regulations governing metallic mine permitting stipulate that protection of groundwater quality be assured indefinitely through all phases of the mining project, including development, active mining, reclamation, and long-term closure. By rule, the Wisconsin Department of Natural Resources (WDNR) requires that permit applicants use a numerical model to assist in the assessment of compliance with this requirement for all proposed mine-waste facilities. As a part of the compliance assessment, model calculations are used to predict groundwater solute concentrations through time at designated boundaries for comparison to current groundwater quality standards. In practice, this modelling requirement has involved the application of numerical solute-transport models. Our review of a solute-transport model submitted by the developers of a proposed mine near Crandon, Wisconsin, provides us with an opportunity to assess the usefulness of transport modelling as a permitting requirement. Recent evaluations of solute-transport models by other workers suggest limitations in predictive accuracy. Our review of the model submitted for this project also identified important limitations due primarily to uncertainty in calibration of model parameters at the undeveloped site. The utility of any model to predict project compliance or non-compliance with numerical standards is limited by the range of uncertainty of key model parameters, such as dispersivity and porosity. Uncertainty in the future behaviour of the solute source(s) also reduces the predictive power. Moreover, the site characterisation provided by the model may have limited power to describe the site condition post-development. Although these inherent shortcomings accompany the use of solute transport models at undeveloped sites, the requirement for model development and the ensuing technical review has substantially assisted in our evaluation of site conditions and project design. Through this process we have identified elements of the waste facility design that are crucial to the environmental viability of the project, resulting in modifications to original project proposals. While results from this model review will be used to evaluate compliance, additional benefits come from the identification of critical design features that enhance groundwater protection.

Jan 1, 2003

By Bockhorst R. W, Christopher D. A

Over the past fifteen years, horizontal drilling in coal seams for advance degasification has become an established practice in the United States of America. Consolidation Coal Company pioneered the development of the horizontal drilling system and licensed the technology in the U.S. A. and to Du Pont (Australia) for commercial production. This paper discusses the most recent developments in the equipment design, especially the borehole telemetry system, known as the Downhole Drill Monitor (DDM).

Jan 1, 1988