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By S Latchireddi

Close circuiting autogenous and semi-autogenous mills is an energy efficient way of grinding and a number of operations have utilised this in the design of their comminution circuits. Owing to the large flow of slurry through the mill that results from operating this way the grates and pulp lifters have to be designed to cope. However, the literature has little or no information on how grate and pulp lifter size and design are related to their ability to remove slurry from the mill. Over the last few years the JKMRC has been researching this area and has developed relationships between grate/pulp lifter design and flowrate capacity. At the same time it has determined the major causes of pulp lifter inefficiency and a solution to preventing this inefficiency (the Twin Chamber Pulp Lifter). This paper describes the models that have been developed through this program and uses industrial scale data to illustrate their accuracy. Results from the industrial trials of the Twin Chamber Pulp Lifter are also presented.

Jan 1, 2000

By Moffatt G

Approval to operate Longwall No. 7 at Appin Colliery in 1979 was granted pursuant not only to the usual statutory provisions, but also that an adequate means of drainage of methane gas be incorporated. A methane drainage plant was subsequently designed and constructed some two km from the pit top at the site of the Colliery main upcast and down cast shafts. Modern plants of this nature are completely automated using programmable controllers and computers to provide control and management reporting functions. Complex mechanical systems are installed to extract the gas and in handling and storage processes. Gas utilisation plants exist which can generate power from methane. These plants are further enhanced by harnessing waste heat produced in the generation process. The installation, automation control and monitoring of these plants incorporates many facets of engineering from high voltage power supply and computer technology to complex gas handling procedures used in gas compression storage.and generation of electric power.

Jan 1, 1982

By V Malysiak, N J. Shackleton

In the flotation of platinum group minerals pyroxene is a major gangue mineral. This study shows using zeta potential and ToF-SIMS analyses that when pyroxene is exposed to copper, nickel and/or calcium ions in solution at alkaline pHs a surface reaction occurs between the hydroxy species, in the case of copper and nickel, or divalent calcium ions and the pyroxene surface which influences the floatability of the pyroxene. Following exposure to copper and nickel ions at pH 9 addition of SIBX resulted in the pyroxene floating readily. It is also shown, in the case of copper, that the activating effect of the adsorbed copper hydroxy species can be reduced by the addition of complexing amines prior to SIBX. Proposals are made to explain these observations.

Jan 1, 2005

By Anderson DR, Tassell G

A major environmental impact study carried out in the sand dunes of eastern Cape York used image analysis of remotely sensed data to both select sites for ground investigation and categorise the different ecological units present. The approach adopted was particularly suited to the type of environment in question and allowed a high degree of quantification, at a high level of confidence, at costs several orders of magnitude less than conventional Methods.

Jan 1, 1987

By S Corbel, P J. T Donchak, W Gorczyk

The Hodgkinson Province numerical modelling project aims to develop an improved understanding of the physical conditions that lead to the localisation of goldbearing fluids within known systems and apply this understanding to the prediction of potential new sites of gold mineralisation. The project follows a series of stages from identifying the key parameters required to construct and test simulations through to reverse engineering of known deposits and ultimately applying the conditions identified in the preliminary stages to predictive simulations. Results of the modelling demonstrate strong geometric controls of the localisation of fluids during mineralisation. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By C Tapia, B Hay

There is a close relationship between the mining industry, economic growth, and technological and social development. Mining activities benefit all economic agents, but only during a timespan determined by available reserves, primarily driven by internal factors such as production rate, technology and costs, and external factors such as prices determined by the market and taxes and royalties controlled by governments (Gordon and Tilton, 2008; Henckens, 2021; Tapia Cortez et al, 2018). The intense use of Mineral Commodities (MC) needed to maintain the current lifestyle has placed ore depletion as one of the main threats to sustainable economic, social and technological development. However, ore depletion does not only arise due to the finite nature of MC, price fluctuations or technological challenges. It is also triggered by the ‘economic limits of extraction’, determined by the optimisation of financial factors and technical restrictions within the regulatory framework (Henckens, 2021). Most reporting standards – if not all – define ore reserves as ‘the economically mineable part of a Measured and/or Indicated Mineral Resources’ determined by the technical and economic viability of extracting, processing and commercialising MC having the NPV as the fundamental decision – making tool (JORC, 2012; Krzemień et al, 2016). However, is the NVP an ‘economically’ basis index able to capture the complexity of economic phenomena? No, it is not, and it is crucial to define what is economic and financial. Although related, they are different disciplines. Economics studies the behaviour of the different market agents, including human behaviour and policies and explains the factors involved in the scarcity (or surplus) of goods and services. Finance focuses on financial systems and managing funds considering the time, cash available, and risk. It involves banks, loans, investments, and savings and can be considered a small subset of economics (Simon, 1959; Tapia Cortez et al, 2018). Given the economic nature of ore Reserves, endorsed by governments (Figure 1), NPV is an incomplete tool to determine ore Reserves as it limits the problem to simply maximising cash flows instead of optimising the economic benefits for all economic agents. In addition, using the rigid scheme of controlling taxation – unable to adapt to new market or economic conditions and systematically increasing – within the NPV framework only increases the sub-optimisation of ore reserves, mainly due to the systematic taxation rise. Short-term benefits of higher taxes and royalties are unlikely to offset the impacts of reducing exploration and project development in the long-term, which not only boosts ore depletion concerns but also reduces competitiveness, threatening economic and social welfare (Fisher, Cootner and Baily, 1972; Gordon, Bertram and Graedel, 2007; Lilford, 2017; Mardones, Silva and Martínez, 1985; Radetzki, 2009; Rodrik, 1982; Tan, 1987; World Bank, 2000). Holistic methods and collaborative tools, able to dynamically simulate and assess how changes in the technical settings, regulatory framework (taxes and royalties), and financial factors affect the availability of ore reserves and the impact for all economic agents, should be incorporated into the evaluation process to fill the gap.

Aug 2, 2023

Increasingly, mineral operations need to manage water as a key business asset. Managing water solely as an environmental issue leaves a business exposed to social, cultural and economic risks associated with water. Adopting a company-wide strategic approach, which takes account of the true value of water will provide businesses with opportunities and risk protection. Rio Tinto has recognised the business imperative for water stewardship and has responded by producing the Rio Tinto Water Strategy. This strategy commits the company to managing water assets in a responsible manner, taking account of environmental, social and economic values. To incorporate the true value of water in site decision making, a new set of tools is required at the operational level. A key part of the strategy focuses on developing a framework to value water based on case study examples from around the Group. This paper presents progress on the companyÆs experiences in developing and implementing the water strategy.

Jan 1, 2006

Over the last five years Du Pont (Australia) Ltd has developed a commercial range of new generation emulsion based explosives concurrently with the development of new explosives-placement systems. The paper outlines Du Pont's emulsion technology and history of product development from the initial emulsions (Tovex E & EL) to emulsion/ANFO blends (Tovex BE) through to the most recent development of Du Pont's SOL emulsion component. The paper also outlines the development of materials handling systems on site to load waterproof bulk explosives from the original pumper trucks through to the multipurpose agitator bowl blending and pumping units at the heart of Du Pont's SOL emulsion system currently available within Australia. The last section deals with some of the more important features of enhanced agitator bowl truck designs and outlines examples of the complete SOL emulsion system and methods of operations currently practiced at specific mines within the Bowen Basin coalfields.

Jan 1, 1986

By L C. P J Fonteneau, B Godel, E R. Ramanaidou

The Hamersley Province in Western Australia hosts large iron ore deposits. Each deposit displays various iron ore types that were defined on their metallurgical properties, especially in terms of porosity and mineralogy. Conventional porosity and mineralogy information on iron ore types are provided on 2D thin sections using automated image analysis with scanning electron microscopy (SEM)-based techniques combined with chemical analyses. However these techniques cannot accurately quantify the 3D porosity. High-resolution X-ray computed tomography (HRXCT) is a non-destructive technique providing a 3D image of the sample with a resolution close to 0.5 - 0.7 ¦m for samples size of up to few centimetres in length. 3D image analysis using customised algorithms now provide accurate quantitative porosity and mineralogy of iron ore types.CITATION:Fonteneau, L C P J, Godel, B and Ramanaidou, E R, 2013. Application of high-resolution x-ray computed tomography to iron ore characterisation, in Proceedings Iron Ore 2013 , pp 243-250 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By R W. Wilson, A R. Branch, T S. Pooe

The original bulk air cooling system at this particular mine made use of two water chilling refrigeration machines to produce peak cooling of approximately 12 MWR with a downcast air temperature of about 7°C; however, as the shaft is not used for transporting personnel, the opportunity existed to supply more cooling to the mine by lowering the downcast air temperature. An ice storage facility has been constructed and provides a range of opportunities in operating the system: colder air temperature sent to the shaft, enabled by using near-zero degree water produced by melting ice to cool the air; electricity time-of-use management, by shifting electricity usage out of peak tariff periods; and increased peak cooling capacity, by melting ice while chilling water. Ice is created in the storage facility at night while the ambient air temperature is low and then melted to produce cold water when required by the cooling process. An ice dam was constructed and serpentine stainless steel coils installed where the ice is produced; one of the refrigeration machines was converted to chill a glycol solution to subzero temperatures to create the ice on the coils; a plate heat exchanger was installed to allow the glycol chiller to act as a water chiller as well; and a third spray stage was added to the bulk air cooler to utilise the near-zero water. This paper describes the thermodynamic design, construction and performance assessment of the new system, which is unique, novel and represents the state-of-the-art of this type of cooling system and energy management.CITATION:Branch, A R, Wilson, R W and Pooe, T S, 2015. Novel use of ice thermal storage for energy management on a mine refrigeration plant, in Proceedings The Australian Mine Ventilation Conference, pp 185–192 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By E du Plessis, M Rowley, M Fallon, F Golenya, R Swanson, I Robertson

"Check sampling programs were undertaken at Barrick Australia Pacific LimitedÆs Lawlers and Plutonic mine sites in Western Australia. The programs identified that the sampling, sample preparation and assaying protocols required modification to ensure acceptable precision (reproducibility) for each gold mineralisation type. These case studies describe the processes used to identify the: inconsistent precision different types of test work programs that were conducted to quantify the appropriateness for each mineralisation type steps used to modify the protocols.The type of test work conducted included: a duplicate series heterogeneity test for particulate gold mineralisation in the Lawlers gold deposit screen fire assay test work on duplicate subsamples for arsenopyrite associated mineralisation at the Plutonic gold deposit.Each test work program required a detailed scope specifying the sample selection criteria, sample preparation and assaying steps. The aim of the test work flow chart design was to ensure the assay precision between the different particle sizes or duplicate sample pairs could be measured and calculated. In the screen fire test work the true grade of the primary sample was calculated and compared against each subsample.A high quality assay laboratory was utilised for the test work. All samples were fire assayed and the gold grade determined using a gravimetric finish. The assay results were validated and the data was analysed using tables and graphs in spreadsheets. Following data analysis a modified sample preparation and assaying protocol for each mineralisation type was designed for use by the principal assay laboratories. Following implementation of the new protocols, routine check samples were collected during the sample preparation and assaying stages to monitor the performance of the new protocol.CITATION:Fallon, M, Rowley, M, Du Plessis, E, Golenya, F, Robertson, I and Swanson, R, 2012. Confirming the sampling, sample preparation and assaying protocols used at two Yilgarn gold deposits, in Proceedings Sampling 2012, pp 47-62 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 21, 2012

By P Andrieux

By 1996 ground control-related problems at Brunswick Mine had raised serious concerns regarding the safe and economical extraction of large portions of the reserves. These difficulties were mainly caused by high stress levels in pillars, instabilities resulting from wide spans supported by ageing support elements, and chronic difficulties supplying rock fill from the surface quarry to the underground workings, which resulted in many large voids remaining open for long periods of time. Significant changes have been implemented at the site since 1996, amongst which were a change of mining method, the introduction of paste backfill, the establishment of stress management measures, and the introduction of shotcrete on a large-scale. This paper focuses on the regional ground conditions associated with both the previously used primary-secondary mining method and the newly implemented pyramidal pillarless technique, as well as on some of the stress management measures implemented at the mine.

Jan 1, 2000

By I Treloar, T Elenbaas, E Isaaks

Critical reviews of grade control generally focus on blasthole sampling and the estimation of ore control block model (OCM) grades, with little or no attention given to dig-line design. For example, the estimation of block grades is deemed important as estimation errors lead to the misclassification of ore types and subsequent dollar loss. Recognition of the problem that the underestimation of block grades may be more or less costly than overestimation led to the application of loss functions to the classification of individual OCM blocks by ore type. The method is known as maximum profit selection (MPS). However, each OCM block may be misclassified a second time by dig-line design. Although each block may initially be assigned an optimum ore type by MPS, OCM blocks are seldom individually mineable by ore type. As a result, a common solution to this problem is the design of mineable polygons or dig lines loosely constrained by a minimum mining width. All material within a properly designed dig-line polygon can be mined and sent to a single destination such as the mill, stockpile or waste dump. These dig lines are often designed manually or by simple variations of computer-generated contour lines. They are generally suboptimal and result in additional misclassifications of ore types. This paper provides an algorithm for constrained optimum dig-line design where dig-line misclassifications are also evaluated through loss functions or MPS. Constrained optimum dig-line designs minimise the dollars lost by dig line misclassifications for a given minimum mining width constraint. A case study is provided illustrating constrained optimum dig-line design and subsequent benefits.CITATION:Isaaks, E, Treloar, I and Elenbaas, T, 2014. Optimum dig lines for open pit grade control, in Proceedings Ninth International Mining Geology Conference 2014 , pp 425–432 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

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 A Fareth

Constructed between 1885 and 1891, the New Croton Aqueduct (NCA) in New York State is a 50 km long (31 mi) brick-lined tunnel conveying water from the Croton watershed north of New York City to distribution systems in the Bronx and Manhattan. Except at two siphons, the aqueduct operates as an open channel conduit from the New Croton Reservoir downstream 39 km (25 mi) to the Jerome Park Reservoir in the Bronx. The remaining 11 km (6 mi) is operated as a pressurised conduit and includes a major siphon, of circular cross-section, under the Harlem River. The aqueduct has a flow capacity of approximately 1100 million litres of water per day (13 m3/s or 290 million gallons per day) and supplies on average ten per cent of New York CityÆs drinking water. The CityÆs water supply system is operated and maintained by the New York City Department of Environmental Protection (NYCDEP). This paper covers the work done during the three main stages of the program to rehabilitate the entire NCA: inspections, design and rehabilitation. It also includes some of the more interesting structural findings of the original construction as well as documents and drawings from the NYCDEP archives. The rehabilitation program has been underway in phases since 1993, with inspections scheduled to minimise outages, allowing this strategic aqueduct to remain in service during critical seasonal periods. The open channel flow section of the aqueduct in the north is horseshoe shaped, with inside dimensions of 4.1 m (13.6 ft) in width and 4 m (13.5 ft) in height. The pressurised section is 3.7 m (12.3 ft) in diameter, and includes a 90 m (330 ft) deep siphon under the Harlem River. A total of 163 million bricks were used in the construction, enough to build a 48 km (30 mi) wall around Manhattan Island, 3 m (10 ft) thick and 15 m (50 ft) high.Between 1993 and 1997 a series of in-tunnel investigations were performed in the open channel portion of the NCA, consisting of field inspection, non-destructive geophysical testing, and coring of the brick liner. Between November 2004 and September 2005, a major inspection program was conducted to assess the condition of the 11 km (6 mi) long pressurised section and all shafts, headhouses and blow-off structures along the entire 50 km (31 mi) alignment. Inspection methods included using an underwater remote operated vehicle (ROV) equipped with sonar and cameras to inspect the deep siphon, fibre optics examinations of probe holes drilled through and beyond the brick lining, and core holes and geophysical inspections to assess properties of the liner and behind-the-liner materials. A water pressure and test grouting program was conducted to assess methods and expected grout takes for the rehabilitation work in the pressurised sections. The rehabilitation program is anticipated to be completed in 2010.

Jan 1, 2008

By H Zhang, Y Wang, S Sukenaga, H W. Ni, H Shibata, W Z. Mu

The crystallisation behaviour of low melting point CaO-SiO2-Al2O3-MgO inclusions greatly affect the deformability of inclusions during the rolling process. The crystallisation characteristics of CaO-SiO2- Al2O3-MgO melts representing the oxide inclusions in Si-Mn killed steel were systematically investigated. The effect of Al2O3 and MgO contents on the crystallisation change were analysed under a fixed CaO/SiO2 in the complex inclusions. The continuous-cooling-transformation (CCT) and time-temperature-transformation (TTT) experiments were conducted. The results showed that the increase of MgO content increases the crystallisation ability of CaO-SiO2-Al2O3-MgO inclusions, while the increase of Al2O3 content has the opposite effect. The viscosity, liquidus temperature of oxide melt and also the initial crystallisation potential might be the reasons for the change in crystallisation behaviour. Also, the crystallisation activation energy could semi-quantitatively characterise the crystal growth during the crystallisation of inclusions. To obtain low melting point plasticized CaO-SiO2-Al2O3-MgO (CaO/SiO2=1) system inclusions, the Al2O3 content of the system needs to be controlled larger than 15 wt per cent and the MgO content should be kept at a small amount.

Aug 21, 2024

By S Karosiya, A Sharma, M Jain, N N. Viswanathan, M M. Pande, D Kumar, S Kumar

Desulfurisation of steel during ladle refining is governed by both thermodynamics and kinetics. For effective desulfurisation, thermodynamically, a low partial pressure of oxygen at the steel-slag interface and highly basic slag which possess a large sulfide capacity are desired. Kinetically, the mass transfer coefficient of sulfur in the liquid steel and in the slag determines the rate of desulfurisation. A fast desulfurisation rate is achieved by maintaining sufficiently strong argon stirring of the melt. In the present work, sulfur mass balance for steel and slag was performed after the desulfurisation treatment for several industrial heats. The decrease in the sulfur quantity of the liquid steel was more than the increase in the sulfur quantity of the slag. The discrepancy in the sulfur mass balance suggests that the sulfur could be transferred to: (a) the gas (via slag) phase; or to (b) the refractory (crucible) phase. The preliminary investigation of the refractory samples taken at slag-refractory and steel-refractory interface showed no interaction of sulfur with the refractory. Therefore, the possibility of sulfur transfer to the gas phase was verified by carrying out melting experiments of sulfur containing slag in an argon/air atmosphere. Sulfur containing slag was initially melted in an MgO-C crucible under an argon atmosphere followed by creating the air atmosphere just above the melt. Careful sampling and analysis from the cold spots of the crucible, much above the melt surface, revealed formation of a fibrous structure. Scanning electron microscopy energy dispersive X-ray spectroscopy (SEM-EDS) analysis of these fibrous deposits confirmed the presence of oxides and sulfides. Oxidation of sulfur containing slag under air atmosphere was also performed using a thermogravimetric analysis (TGA) set-up. It showed a constant sulfur loss in the range of 1300– 1500°C. Thermodynamic calculations carried out using FactSage™ ver 8.3 for these experimental conditions are in good agreement with the observed results.

Aug 21, 2024

During the development of Lorca tunnel project in the South-East of Spain, an in-site study has been done, with the purpose of obtaining the characteristics of the different lithological units through twenty-two parameters for the design of the tunnel excavation and support. In the paper both the different works developed and the different methods and criteria followed in the obtention of the parameters are described. The values of those parameters may be useful in similar cases. Also a summary-table of the parametrical characterization for the use in similar studies is given.

Jan 1, 1987

Universities have had a long history in the education of geology graduates, Analysis of this history reveals a record of success, as judged on a world basis. However there have been significant changes in the last 20 years that have impacted on the ability of universities to continue to provide their traditional style of geology education. These changes have increased in the last 10 years. In the teaching side, there has been a change in expectations. Additionally the increasing workload decreases the value of each academic to perform the tasks needed by the new education. In the area of research, the funds provided have continued to decline, in both real and absolute terms, and it is now necessary for universities to seek out funds to pay for their postgraduate research. Additionally, the universities have slipped into the error of what cahn only be termed "academic incest", and research student mobility has decreased to an undesirable level, stifling initiative and new ideas in a number of cases, The only solution is for Government monies to be "directed" - ie that the postgraduate student must leave his or her original university in order to receifve the research stipend/scholarship. On the government front, the government and its agencies have not adequately analysed and recognised the need for the redirection of education and research funds into the needy areas of science and technology, especially those that related to the minerals area.

Jan 1, 1986

By S Walters

The emerging discipline of ‘geometallurgy’ is not new but is becoming increasingly recognised as a discrete and high-value activity. Geometallurgy involves a quantified and spatially constrained approach to ore characterisation in terms of relationships to critical processing performance behaviours. A key outcome is enhanced economic optimisation of mining and improved risk management tools.Industry recognition of the need for large-scale, integrated research to support this emerging area resulted in commencement of a major ongoing initiative in mid-2005. The AMIRA International P843 ‘GeMIII’ project (Geometallurgical Mapping and Mine Modelling) is a cross-discipline collaboration involving a number of world-class research organisations supported by over 20 industry sponsors.The project is delivering integrated tools and methods which link intrinsic rock characteristics to prediction of mineral processing performance. These indices must be capable of spatial distribution in 3D resource models and incorporation into mine planning and optimisation. A key aspect is provision of new cost-effective tools and methods which can provide the large numbers of measured and estimated data points required to undertake effective modelling and spatial distribution. The integrated methodology and enabling technologies being developed through the ongoing AMIRA GeMIII project are outlined, together with implications for supporting industry best practice.

Sep 5, 2011