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By Robertson K. S, Hunter T. C

AEG-Elotherm's electromagnetic dosing channel, or Eldomet, is a recent invention enabling the transport and metering of molten metals. The development of a reliable refract- ory lining, and the use of suitable construct- ion and operating techniques has led to the successful application of the Eldomet for casting copper anodes at Copper Refineries Pty. Ltd.

Jan 1, 1974

By E Kunz

Decreasing the gas content in the worked seam by degassing before the start of winning has proven its worth in some areas of German hard coal mines. On the one hand, it removes the risk of gas/coal outbursts and on the other hand it reduces the gas inflow into the longwall. The underground experiences of the last 30 years have led to a æhit listÆ of coal seams with respect to their suitability to predegassing. Trials in the DMT laboratory and also results gained in the deposit show that the suitability of a seam for predegassing depends on its rank. In seams with volatile matter of 20 - 30 per cent, high efficiency ratings are achieved as a rule, with lower ratings both in seams with lower and with higher content of volatile matter.If the rock pressure is unusually high, the efficiency rating of the predegassing is lower, even in seams which would normally be suitable for this process. Under unfavourable conditions, for example below or above residual pillars, in-seam boreholes cannot be drilled successfully and the method is not practical. But if the worked seam was already stress relieved, the predegassing has an optimal efficiency. Latest investigations show that the distance between the in-seam boreholes can be extended. But in that case, the time necessary to reach the same reduction of the gas content increases considerably.

Jan 1, 2005

By R Barritt, P Scott, K Albano

Successful closure of tailings storage facilities (TSFs) is an environmental issue faced globally by metalliferous mines. During the initial feasibility and design phase of the mine life importance is placed on the physical stability of above ground TSFs, largely driven by legislative requirements, whilst closure planning is often a secondary consideration. However, as the landform is further developed and constructed attention must be paid to regularly revisit the original closure plan and update it to achieve the best (sustainable) possible outcome for both the environment and stakeholders. A mine in northern Queensland is in the process of developing a closure strategy at their TSF. Appropriate closure measures for the TSF are required to mitigate the impact of any seepage emanating from the TSF on the groundwater and surface water receptors. O’Kane Consultants Pty Ltd (OKC) have provided the mine assistance with the development of a TSF cover system design in order to appropriately manage tailings during operations and to prepare for the facilities’ closure. OKC has collected data since 2007 from cover system field trials located on the TSF. To enhance engineering judgement in the design of future cover systems, calibration of soil-plant-atmosphere numerical models to field data (referred as ‘field response modelling’) were completed. Calibrated model inputs can be used to provide insight into long-term cover system performance as well as a tool for design of the final landform.Following a site investigation, materials characterisation and numerical modelling program various cover system alternatives were developed. Two of the preferred cover system alternatives referred to as Test Plot #1 (TP#1) and Test Plot #2 (TP#2) (Figure 1), were constructed at the site and instrumented. Monitoring instrumentation comprised several nests of in situ volumetric water content and thermal conductivity sensors to measure changes in water content, temperature and matric suction within the cover system materials and underlying tailings waste. Run-off collection buckets and a fully-automated meteorological station were also installed. CITATION:Barritt, R, Albano, K and Scott, P, 2016. Findings and conclusions following ‘long-term’ cover system monitoring – refinement of the conceptual design for tailings storage facility closure, in Proceedings Life-of-Mine 2016 Conference , pp 85–88 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By W Newton, J Price

This paper outlines the design, justification and performance of a gravity circuit upgrade at the Marvel Loch treatment plant. The design of the upgrade was simple but effective. The key components of the upgrade were the addition of a sluice and a second Knelson Concentrator. The sluice was installed as a pre-concentration step. The upgrade also included the purchase of a Mineral Cone to treat the increased quantity of gravity concentrate. The cost was low because of the use of mostly second-hand equipment. The result was that for a cost of $75 000 the gravity recovery doubled and the overall recovery increased by over one per cent. This paper shows that you do not need to spend millions of dollars to be innovative and successful.

Jan 1, 2000

By N Winkelmann

Underground coal heating is a significant hazard in some coal mines. The broad principles of how underground coal heatings occur is reasonably known, however the technique for locating the heatings in often inaccessible goaf has been proved to be difficult. Since 2002, CSIRO, with the support of the Australian Coal Association Research Program (ACARP) has been undertaking investigations to apply and develop innovative surface-based radon technique for locating the underground heatings in Australia. This paper presents the progress of the investigation.

Jan 1, 2005

By B J. Monaghan, R J. Longbottom, S Prabowo, D Del Puerto, B Maisuria, C W. Bumby

The use of hydrogen as a reducing agent can substantially reduce carbon dioxide (CO2) emissions from the ironmaking process. Iron ore fines can be reduced in a fluidised bed (FB) using hydrogen (H2) at high temperatures (>800°C), although several studies have reported the sticking of particles which causes the bed to defluidise, effectively shutting down the process. Here, we report results from the reduction of New Zealand (NZ) titanomagnetite (TTM) ironsands in a small-scale laboratory FB (100 g) at temperatures between 800–1000°C using H2 flow rates up to 5 standard L/min. No sticking phenomena are observed under any of these conditions, which is attributed to the formation of a stable titanium-bearing oxide layer on each particle’s exterior, preventing iron-iron contact at the particle surfaces. Pre-oxidised NZ TTM ironsands have also been studied and shown not to stick. Interestingly, at lower reaction temperatures the reduction kinetics for pre-oxidised ironsands is faster than for as-received ironsands. This increased kinetic rate can be attributed to the preoxidation stage inducing micro-fractures that create a void for the hydrogen to diffuse into the inner regions of the particle. In addition, oxidation of TTM appears to segregate the particle into two distinct phases, a high Aluminium-Magnesium (Al-Mg) phase and a high Titanium (Ti) phase. The findings are important as increasing the operating temperature of the FB reactor results in a faster reaction rate and higher gas utilisation, making the process more economically attractive. Furthermore, oxidation of NZ TTM ironsands results in a faster reduction rate at lower temperatures (800°C– 900°C) opening the opportunity to reduce the reaction temperature which might be beneficial in a final commercial-scale process.

Sep 18, 2023

By R G. Moreby, S Bluhm, FávonáGlehn, C Pascoe

Resolution Copper Mine in Arizona, USA, is planned to be a 2000 m deep panel cave mine with virgin rock temperatures exceeding 80¦C in rock with high crystalline silica content, resulting in a very challenging ventilation and cooling system design. This is one of the largest copper orebodies ever found and, with a planned rock production rate of 120 kton/day. The project is currently in its prefeasibility phase and the paper discusses features of the ventilation and cooling system design which includes multiple ventilation shafts with total primary ventilation flow of about 3000 m3/s and both surface and underground refrigeration plants producing more than 140 MW refrigeration capacity. The cooling system features large surface bulk air coolers chilling all downcast air supplemented by an underground secondary air cooler system and a chilled service water system. This will be a very challenging mine to ventilate and cool but this work has demonstrated that it will be technically achievable with the application of existing technology.CITATION:Bluhm, S, Moreby, R G, von Glehn, F and Pascoe, C, 2013. Life-of-mine ventilation and refrigeration planning for Resolution Copper Mine, in Proceedings The Australian Mine Ventilation Conference , pp 125-138 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By P Hatherly, H Gurgenci

With the depletion of the mineral reserves that can be mined by surface mining, demand for highly productive and safe underground mines will increase. Underground drill and blast techniques continue to be refined but true æmass productionÆ is difficult to achieve. As is evidenced by the longwall mining of coal, alternative mining methods based on mechanised mining can meet the expectations but the issues of how to effectively cut strong rocks, how to define the orebody and how the mechanised miners can be automated and maintained all need to be addressed. CMTE is working in all of these areas. We believe that the oscillating disc cutter may provide the long sought-after breakthrough in mechanised rock cutting. Disc cutters are one of the most robust designs of cutting tool and the cutters attack the rock in a manner which effects direct tensile breakage. The internal cutter drive and the inertial damping mean that the already low cutter forces are not all transmitted back to the machine, making it possible to design lightweight, flexible mining systems. For orebody delineation drill monitoring, drillhole logging and geophysical imaging are key procedures being developed at CMTE. To automate mining machines, work is progressing well in the development of systems for autonomous vehicle navigation and mining robotics. A strategic contribution to maintenance issues is being made through the development of procedures for automatic analysis of used oils, monitoring the strength of mechanical structures, and operating point optimisation.

Jan 1, 1998

By J Field

Many aspects of water use in mining are driven by the technical requirements for water. There has been little consideration given to both the safety and the health requirements. Workers in the mining industry are exposed to water from a range of treated and untreated sources. The intended use of this water dictates the required quality of the water, sometimes with limited consideration for contact with miners. Particularly for underground workers, there is exposure while working in and walking through groundwater possibly contaminated by hazardous substances. Where controls are inadequate the outcomes of this exposure can result in disease, illness and injury û the costs of which can be significant. The situation could also arise where, due to the lack of human exposure, the controls are unwarranted and the financial cost unjustified from a health perspective but warranted from an equipment management standpoint. In addition to the health aspects, water can impact on a range of safety issues resulting from high pressure usage, dust suppression, fire fighting and other processes. The protocols and procedures in place need to consider the safety issues in addition to managing water usage. The current state of water management in mines from an occupational health and safety perspective has been ascertained from a survey targeting underground and surface coal and metalliferous mines. This survey considered the health and safety issues associated with water use, the types of surveillance, control protocols and the strategies that the mines have in place to manage the health and safety risks associated with water systems. The results assisted in the identification of potential occupational health and safety risks associated with water systems and the management processes that may be appropriate from a risk management perspective. Health and safety issues are often neglected but remain critical issues affecting the value of water to the mining industry.

Jan 1, 2006

By R Moller

Reconciliation at large iron ore operations is a complex and time- consuming process. Often the volume of data and the large range of different stakeholders makes the process almost impossible. Up until recently geologists and engineers at these operations would spend hours cutting and pasting data in and out of monster spreadsheets, diligently comparing how resource/reserve models, grade control and survey pick-ups compare to what was actually produced. In 2003 the Sishen Iron Ore Mine in South Africa broke this cycle by implementing SnowdenÆs Reconcilor software. The implementation of a dedicated reconciliation system required a number of existing practices to be changed, with the involvement of stakeholders right across the mine. Data sources had to be clarified and validated, terminology had to be standardised, processes needed to be documented and some methodologies needed to be updated. This was a task that required significant effort by Kumba personnel so that the system could be successfully implemented. This paper provides a case study of the reconciliation system implementation at Sishen. It is a story of an operation that evolved from using a number of fragmented reconciliation processes to using a unified automated system. This paper outlines the key estimates and measurements that are used for reconciliation, details the characteristics of an automated web-based information management system to facilitate the process and provides some insights about the benefits that have been gained though the use of a rigorous reconciliation process.

Jan 1, 2005

By M Norbert, P Mok

The mainline running tunnels for Legacy Way comprise of two-lane tunnel boring machines (TBM) driven tunnels. The length of the TBM tunnel section is approximately 4.2 km. The TBMs employed are double shield TBMs. Typical support to the segment ring while advancing a double shield TBM comprises of filling the excavated annulus between the ground and the segmental lining by injecting pea gravel, followed with primary grouting to fill between the pea gravel some distance behind the excavated face. The methodology adopted for the Legacy Way project, however, did not follow this typical approach, instead, two component grouting of the annulus was carried out.Where the annulus is typically filled with pea gravel, support is provided to the segment ring very close to the end of the tail shield, whereas in the case of two component grout this is not practical as the risk of grouting in the tail shield is high. The staging of the two component grout injection, the grout early age strength properties become key issues in ensuring that the segment ring leaving the TBM tail shield is stable and can support the necessary external loads.Two-component grout is a grout with two components, cementitious grout (component A) and accelerator (component B), commonly adopted for earth pressure balance (EPB) TBM. The grout reaches its thixotropic state in a matter of seconds providing initial support for the segment rings. Manual injection of two component grout to fill the bore annulus was carried out in stages leaving a portion of the segment rings unsupported. Ring stability during TBM advance was provided by a combination of ram thrust and the segment circumferential joint shear connectors.This paper outlines the design considerations such as rock load derivation by probabilistic analysis carried out utilising the software JBlock, 3D finite element analyses using the software Strand7 for ring stability and the testing and back analysis of the shear connector load bearing behaviour. In particular, the actual available capacity of the shear connectors against their published capacity by supplier was discussed.CITATION:Mok, P and Norbert, M, 2014. Tunnel boring machine excavation stability – double shield tunnel boring machine advance with partially grouted annulus, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 51–62 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By N Boughen

This paper synthesises the findings of five studies undertaken by the CSIRO Wealth from Oceans Flagship in 2009-10. This research explores the concerns, expectations, and information needs of a range of stakeholders, (ie government, seafloor exploration and mining industry, other marine industries, environmental non-government organisations (NGOs), community members) in relation to the possible exploration and mining of minerals and aggregates from the seafloor, as well as the conditions for meaningful engagement with communities regarding seafloor exploration and mining (SEM) activities. The SEM industry has been described as the ‘next minerals frontier’, as incentives to explore and mine seafloor resources increase because of diminishing reserves of easily accessible onshore mineral and aggregate deposits. However, the conditions (if any) under which SEM would be acceptable to stakeholders (notably the public and regulators) have not been established. This work seeks to address this gap and ascertain the levels at which potential environmental and social impacts become unacceptable to those stakeholders. The research follows an earlier phase of studies undertaken in 2006 - 2008 that: identified the opportunities and barriers to the development of SEM in Australia, took the first step towards understanding the public and political contexts surrounding the industry, and mapped the positions of key stakeholders and captured their major issues and concerns. Together, these two phases of research confirm that environmental concerns dominate stakeholders’ responses to the idea of an expanded industry. However, the most recent phase of research has also found that, similar to current onshore scenarios, reservations due to environmental concerns do not completely outweigh social and economic objectives. This is provided stakeholders feel confident that there are systems in place (regulatory frameworks, watchdogs, independent research, and stakeholder consultation) to ensure that all interests are protected. When making decisions about the social acceptability of potential seafloor mining, stakeholders favour a precautionary approach, supported by rigorous scientific analysis of the potential environmental impacts, transparent and socially responsive management processes, and meaningful stakeholder engagement. This paper outlines the details of these findings, which may also be relevant to understanding the social acceptability or ‘social licence to operate’ for other future mining scenarios featuring a new approach or technology.

Nov 22, 2011

By C Preston, T Williams, D Roy

The easiest way to mine valuable orebodies is through the use of explosives and well-planned blasting layouts that produce fragmentation profiles designed specifically for conveyance equipment in underground mines. The design of blasting patterns is specific to not only the explosives being used but also the rock or ore type being fragmented. Many blasting designs are based solely on the experience of those developed for similar orebodies in terms of properties and orientation or individuals that have some blasting experience.The primary technical objective of this paper is to outline a unique methodology for determining underground blasting methodologies (developing specific blasting parameters) commensurate with explosive energies and rock/ore equations of state for a narrow-vein gold property located in Northern Quebec and for underground mines in general.The procedures developed are to define the desired fragmentation specification so that a specific thermodynamic break is generated, taking into account powder factor, energy factor, tonnages, explosive energies and distribution along with blasthole diameter and orebody orientation for a specific set of explosive and dynamic rock/ore properties. Determining dynamic modulus values for the ore using seismic sensors to measure P- and S-wave velocities, the aforementioned parameters will be utilised to set the design constraints to maximise recovery and minimise overbreak and dilution.New underground blasting software (AEGIS) will use thermodynamic break in conjunction with defined fragmentation profiles to create an array of blasting parameters used to design and plan ring layouts. This software will also allow mining planners, prior to drilling and loading a production blast, to appraise future intended blasting patterns to minimise the potential of diluting ore with host rock and the likelihood of damaging mine support structures.CITATION:Roy, D, Williams, T and Preston, C, 2015. Underground stope drill and blast designs optimisation program, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 137–148 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

Production targets are the basis for almost every decision made by operations personnel in the daily operation of a concentrator. It is the production targets that determine how the plant is operated and therefore determine its efficiency. However, to achieve maximum plant efficiency production targets must be relevant to the process and achievable.In RoseberyÆs case, for many years, production targets were taken from budget data which, with the exception of mill feed tonnes and grades were carried forward from the previous budget. The zinc concentrate grade target was fixed at 57 per cent Zn, a long-term average; it was the accepted æstandardÆ for Rosebery. Historical data showed this target was never consistently achieved and plant efficiency was highly variable.Investigations into the possible causes for the variable performance ruled out plant and mechanical issues. Despite the Rosebery concentratorÆs age the plant and equipment are more than serviceable and reliable. The mineralogy of the ore and specifically the iron content of the sphalerite was found to be the most significant determinant of zinc concentrate grade. It was found with increasing frequency that the zinc grade of the sphalerite in the ore was below the zinc concentrate grade target. Consequently on these occasions attempts to meet the required concentrate target destabilised the process resulting in plant inefficiencies.Using the correlation between iron and zinc, data modelling was able to accurately predict the maximum zinc concentrate grade achievable for any ore type. By using on stream analysis instrumentation the operations personnel are now provided with constantly updated concentrate grade targets. By knowing the mineralogical limits of the ore at the time it is being treated process stability is maintained allowing plant efficiency to be optimised. This has resulted in a step change in plant performance and a significant increase in revenue.CITATION:Harris, G R, 2012. Developing and implementing ore-specific targets for the Rosebery Concentrator, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 321-324 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

This paper describes the technical development of the Newman beneficiation plant over its 23 years of operation and how this development relates to the mine ore reserves of high-grade and low-grade ore. It also discusses the importance of the beneficiation product grades in the overall blending of shippable products from a range of mines to optimise overall ore resource utilisation. Also discussed is the importance of the ore reserve reconciliations in resource utilisation. Data is provided on the capacity and quality improvement results of the plant upgrade, carried out in 1999. This shows how the original capacity upgrade targets have been exceeded and the additional quality benefits that have been obtained from this capacity.

Jan 1, 2002

By Ride G

The provision of a water supply is a major consideration in planning mining developments particularly in remote areas. The evaluation and development of adequate water supplies in and areas of Australia is often as important as the discovery of the orebody. The copper orebody at Warrego near Tennant Creek could not be mined economically if cheap treatment water was not available near the mine. This paper describes the difficulties in obtaining water in the Tennant Creek area and the water supply investigations carried out near the Warrego Mine which resulted in the successful discovery and evaluation of a reliable large scale water supply. It is contended that the establishment of a water supply must be approached on a systematic and scientific basis similar to the approach with the exploration and establishment of actual ore reserves. Mining companies with similar water supply problems may benefit by approaching their problem on this basis. The approach adopted by Peko Mines is outlined in this report.

Jan 1, 1980

By A Castleden, G Cavanough, M Kochanek, J Cunningham

ROES« is a proposed new mining system for underground hard rock mines. Ore is accessed from within a shaft, which is located close to or within the stope, and pitched either vertical or within approximately 20 degrees of vertical. The shaft is designed to exclude personnel entry so production drilling and explosive placement is done using remotely controlled or automated machines. Routine remotely controlled survey of the shaft, stope back and broken rock within the stope is typically done following each blast. The survey may include excavation geometry, rock fragmentation and geotechnical characteristics. Blastholes are surveyed before placement of explosives. This provides mine operators and engineers with real-time data, allowing them to monitor production performance and risk factors so that they can make rapid changes as required. ROES« is designed to apply to open stoping or sublevel caving situations either in disseminated, geologically defined, thick tabular or narrow vein orebodies. The technologies developed for ROES« will also have potential applications to block caving operations to reduce the risk of frozen ore and poor fragmentation. In a typical sublevel open stope application, ROES« will reduce the amount of stope-associated development by about half and therefore will allow ore to be brought on-stream sooner and at significantly reduced cost. Other savings are expected to flow from the centralisation of mining activities and operational data, reduction in mining fleet, reduction in ventilation requirements, improved occupational safety and reduced mine complexity. CSIRO and Orica Mining Services are developing the required technology and AMIRA is seeking sponsorship for a project to trial the mining method. This paper details the ROES« method, expected benefits and applications and includes typical stope and mining block designs and design requirements.

Jan 1, 2008

By Palmer DJ

Mercury is introduced into EZ's electroly tic zinc/sulphuric acid plant complex at Risdon, Tasmania, in zinc sulphide concentrate. Mercury is volatilised during the roasting operation and then distributed in the sulphuric acid plant effluents and product acid. Following an investigation of the factors determining the mercury distribution, a plan was formulated to-provide an environmentally accep- table degree of mercury containment at Risdon. This paper discusses details of the various control measures investigated and out- lines the reasons for selecting the particular procedures finally adopted for the Risdon plant.

Jan 1, 1980

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

By A P MACONOCHIE

The methods used and some of the results obtained from a major geotechnical study of the Ok Tedi mine area, Papua New Guinea, are described. The study was carried out at both regional and local scales and extended over a two-year period. A team of individual engineers and scientists from a variety of disciplines carried out the work. This study may provide a model for other investigations in similar environments.

Jan 1, 1992