Search Documents

By J Franz, S Bock, N Hentrich

Artificial ground freezing is the unrivalled method for groundwater control during mine shaft sinking. Moreover, ground freezing may also provide temporary ground support. The fast development of fibre-optic temperature monitoring devices, three-dimensional freeze pipe survey methods and numerical modelling software provide grounds for developing new and reliable tools for ground control during freeze shaft sinking. This paper presents examples of predictive numerical models that are based on back-analysis and calibration of temperature data that covers the complete construction cycle from pre-freezing through to artificial thawing. The back-analyses showed that standard numerical models are not capable of predicting the prevailing thermo-mechanical conditions satisfactorily. This paper describes the development and implementation of new tools for improved consideration of concrete hydration and latent heat, along with the introduction of other algorithms that improve and simplify the efforts of managing complex numerical models. A function is presented that allows for an automated correction of the model’s mesh based on results of three-dimensional freeze pipe surveys. This paper demonstrates that the latter consideration is important, because the often employed assumption of idealised freeze circle geometry in numerical models impacts on the accuracy of such model’s predictions. Subsequently, the verification of these extended numerical models is demonstrated. Due to its flexibility, the FLAC3DTM code was employed for the numerical modelling. This software provides the possibility of implementing additional functions written in internal FISH or Python language into the models. It is concluded that state-of-the-art techniques for freeze hole drilling and surveying, on-site monitoring and advanced numerical analysis provide a significant potential for both the design and the operation of largescale ground freezing measures. The application of the extended numerical models for predictive simulations during construction allows for temporary shaft lining optimisation, for assisting in operational decision making and for compensating temporary loss of monitoring data. Suggestions are made for required future work in order to further improve the developed ground control tools. CITATION:Bock, S, Franz, J and Hentrich, N, 2018. New tools for ground control in freeze shaft sinking, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 393–406 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By Adusumilli M. S, Subrahmanyam T. V, Rao V. D

Chance find of an economically important mineral on the sur- face and its exploitation without proper exploration work, has become the habit of humanity since the Bronze Age. The explora- tion and exploitation techniques have, however, been substan- tially improved in the technologically developed western world and system controlled major communist countries. Nevertheless, the greatest need is felt in the Third World countries where large mineral potential exists, but with inadequate investments in exploration and exploitation techniques, a handicap that has been beneficial to the more developed countries, since long. The great number of the Third World countries which are striv- ing hard to develop, need to formulate mineral exploration and exploitation strategies which could enable them to develop their resources. This requires planning and creating new concepts of ore deposit types and genetic models, rheology, economics and their innovation and integration. The following approach could help them to be economically "more independent" by the end of this century. 1. Bridging of pure and applied geology gap, and creating con- sciousness of research and development. 2. Revision of mineral resources concepts adopted to modern technological world. 3. Improved mineralogical research, and determinative miner- alogy as an important asset. 4. Creative research and establishing know-how, with philosophical base for regional exploration projects. 5. Indepth investigation into the origin and growth of earth as a system, and its importance in the association, quality, and quantity of metallic, non-metallic and energy resources con- centrations. 6. Mineral beneficiation, targets and strateties; methods of eco- nomic and improved recovery systems. Development of alter- native technology, and utilization of mineral technology strategies. 7. Theoretical and practical modelling by conventional and com- puter techniques of the existing and expected mineral resources, and mineral development. 8. Critical analysis of the status of mineral economics of the Third World and developed world with forecasts for the year 2000 based on problems faced by the developing world. 9. Minerals at cross roads of International Interdependence. 10. Philosophical, realistic, traditional and modern strategies for mineral development. The dynamic economic system opera- tion in national mineral sector.

Jan 1, 1988

By D Connelly

As the resources sector becomes tougher with rising costs and cyclical metal prices, mining companies need to continue to reduce their costs and do more with less. Many new resource projects fail to come in under or on budget based on Feasibility Studies. Particularly, capital expenditure (CAPEX) proves difficult to achieve for resource projects. A number of resource projects have failed because of aggressive plant CAPEX cost cutting resulting in projects with no surge capacity and are unable to achieve design throughput. In addition, the plants are not operable because of the omissions. In recent times many businesses have also experienced the "costs" of simply implementing aggressive operating "cost cutting” measures as a strategy for solving business performance problems. This paper looks at technology driven, employment related, luxury cuts, department cuts and restructuring cuts. In the past companies used an incremental approach based on the use of past budget information as an integral part of the budget construction process going forward. The use of performance reports and Management Information Systems (MIS) is examined along with the role of continuous improvement in achieving sensible cost cutting.

Aug 8, 2011

By S Tierney, D Cumming-Potvin, I Thin, Y Potvin, D Grant

The preliminary modifying factors for future stope design in the Southern Mine Area of Olympic Dam consisted of only a single, arbitrary value of Equivalent Linear Overbreak/Sloughing (ELOS). In order to improve this, a study was conducted which developed a more comprehensive methodology for assigning ELOS, Equivalent Linear Lost Ore (ELLO) and Equivalent Linear Fill Overbreak (ELFO) to individual stope faces based on geotechnical and mining parameters. The approach used was to look at the simple cases, which were classed as vertical stope walls in good ground (RQD 80-100%), divided into wall orientations (North, South, East, West). The stope walls were also split based on the blasting practice used (toeing, parallel or a combination of the two). The expected ELOS and ELLO from these ‘base cases’ are then modified by parameters which have historically been found to affect stope performance (Hydraulic Radius and Q’). The size of the effect found in the historical data determines the ELOS / ELLO applied. The methodology was summarised in an easy to use flow chart and was applied to all of the proposed stope shapes for the Southern Mine Area and summarised per mining block. This allowed each iteration of the mine plan to be assessed in terms of overbreak (both rock and vertical fill exposures) and underbreak.

Mar 15, 2021

By I Lumsdaine

QNI Pty Ltd operates the Yabulu Refinery located 25 kilometres north of Townsville, North Queensland. The plant treats nickel laterite ores sourced from the Philippines, Indonesia and New Caledonia. The cobalt head grade and overall recovery expectations for the 2001/2002 financial year are 0.161 per cent and 53.8 per cent respectively. Cobalt is a valuable byproduct derived from the nickel refining operation which utilises the Caron Process. Any increases in cobalt recovery that are achieved from the existing relatively low level provide significant improvements to the bottom line of the operation. Towards the end of 2000, a project was undertaken to characterise cobalt losses with the sole purpose of improving cobalt recoveries using a variety of analysis techniques. The Time-of- Flight Secondary Ion Mass Spectrometry (TOF-SIMS û University of South Australia) method was used to verify the presence of surface bearing cobalt species, originating from either co-precipitation or adsorption mechanisms. Cross-section examinations were also performed using Scanning Electron Micrscopy (SEM) and Energy Dispersive X-ray Spectrometry (EDXS). These techniques indicated the presence of high cobalt concentrations (in the order of several per cent) within a select number of roasted and leached ore particles. The phenomenon of cobalt losses due to incomplete leaching within specific ore particles was not widely documented within the Refinery prior to these studies. In order to quantify losses via this mechanism, Mineral Liberation Analysis (MLA û JKTech Centre) was also performed on key samples. This paper serves to document a systematic approach in determining the source of significant valuable mineral losses in an established, operating plant. It discusses the use of a variety of analytical techniques, which have been adapted for the minerals processing industry, but are strongly relevant for plant investigations in the hydrometallurgical industry.

Jan 1, 2002

Better quality at lower cost is today's formula for remaining competitive in a world market. For an integrated steel company, high quality low cost steel production must originate before the blast furnace. In 1979, when U.S. Steel initiated a Quality Management Program throughout its steelmaking operations, efforts began at the coal, ore and flux mines. The objective was to improve the quality and reduce the variability of the critical parameters for steelmaking raw materials, to get the blast furnaces, and subsequently the melt shops, under optimum control. The general details of U.S. Steel's Quality Management Program are discussed and how it was used to promote the desired improvements in steelmaking raw materials. Some of the outstanding results obtained by the cooperative efforts between the mines and the steel plants are reported. The lessons learned by U.S. Steel were through upgrading existing operations and facilities. These principles should now be applied to new projects and the benefits of good quality management should commence from the time new projects are Commissioned.

Jan 1, 1986

By K White, R Hardie, J Merritt, B Kirsch, R Lucas

Constructed stream diversions are a common element of mine sites across Australia. A review of constructed stream diversion performance in the Bowen Basin funded by the Australian Coal Association Research Program (ACARP) in 1999 found over 80 per cent of constructed stream diversions failed to meet regulator and operator expectations. Since that time, improvements have been made in the assessment, design, monitoring and management of constructed stream diversions. Fundamental to these improvements has been the development of a better understanding of the regional stream systems and efforts to replicate the natural stream processes in the function and operation of constructed stream diversions.This paper discusses the history of constructed stream diversions through the Bowen Basin in central Queensland recorded in the outcomes of a series of ACARP funded research projects. Further, the paper reports on the outcomes of a current ACARP funded project that has reviewed the success or otherwise of constructed stream diversions in the region. The assessment has compared the performance of diversions that have been designed to replicate and provide for ongoing stream geomorphic processes with those diversions that were designed and built prior to the development of these design improvements. Based on these investigations we have identified design and construction successes and issues requiring further research and management attention.CITATION:White, K, Lucas, R, Hardie, R, Merritt, J and Kirsch, B, 2013. Challenges and opportunities for constructed stream diversions in the Bowen Basin, Central Queensland, in Proceedings Water in Mining 2013 , pp 73-82 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

By Kikuta K

ISP (Imperial Smelting Process) produces zinc and lead simultaneously from zinc and lead sulphide concentrates and recovers copper and precious metals into a lead bullion. The strength of sinter is important to keep permeability in the shaft of the Imperial Smleting Furnace. The residual sulphur content of the sinter is also important as it causes metal losses into slag. The paper describes an investigation into the sintering operations to improve sulphur elimination and sinter strength. The micro structure of the sinter and the effect of the blast rate, sintering temperature etc have been studied.

Jan 1, 1993

The first step in the mining and processing of nearly any mineral ore is comminution. Since the oil embargo of 1979, the mining companies have been striving to reduce energy consumption and costs. The first serious step was the introduction of in-pit crushing in the early 1980s. With in-pit crushing accepted as a standard design mode, the energy saving emphasis turned to comminution practices. A great deal of attention has been focused on blasting and grinding. The one step that has not been addressed is the primary crusher. This paper will address the opportunities for comminution improvement through optimisation of the primary crusher.

Jan 1, 2004

By P Dean, M Elmouttie

Radar monitors are now widely used in surface mining for monitoring slope deformations and predicting failure events. Their introduction has facilitated better management of risk associated with slope failure during mining and therefore protection of personnel and equipment. However, a wellrecognised problem is that radar monitors only measure deformation directed towards the detector (line-of-sight bias). This bias can lead to misinterpretation of deformation size, rate and failure mechanism, and therefore miscalculation of failure volume, which can significantly impact safety and productivity. This paper presents recently completed research and field trials into the feasibility of using low cost vision systems to mitigate this issue. It has been demonstrated that by integrating a computer vision system with an existing slope monitor, high precision tracking of features in the field of view can be performed. Combined with assumptions on the deformation characteristics, the true 3D deformation vector can be estimated. The applicability of using this technique for monitoring iron ore mine slopes is discussed.

Nov 8, 2021

By D C. Curry, M F. Young

Many flotation operations need to improve liberation to increase recovery, yet often plant operators are concerned that finer grinding will produce æslimesÆ with low flotation recovery. Yet simple circuits can be designed to give good liberation and excellent fines recovery. The economics of fine grinding has changed fundamentally with new stirred milling processes like the IsaMill. This has also transformed flotation design due to the clean surfaces produced in the inert grinding environment and the narrow size distribution produced by the IsaMill. Past poor experiences with æovergrindingÆ in flotation circuits was often due to the wide size distribution and the degradation of mineral surfaces produced by conventional devices using steel media, like ball mills and tower mills. The correct practice is to design both grinding and flotation together to suit the liberation characteristics of the ore. This may result in several stages of grinding and flotation, recovering mineral as soon as it is liberated, then applying further grinding energy only to those particles that still need liberation. Flotation then occurs in relatively narrow size bands and with minerals with similar liberation characteristics. Though the circuit may look more complex on paper, in reality it is far simpler to operate since each section performs predicably. Circuit design also needs to address materials handling. Finer particles affect froth handling and dewatering, but can still be easily handled by standard products with careful attention to design of launders, pumps and pumpboxes, and de-aeration before thickening and filtering. Excellent examples of designing circuits to include ultrafine grinding include Mt Isa and McArthur River (MRM). In the last decade these operations have produced over ten million tonnes of concentrate with an average grain size below 10 ¦m and above 80 per cent recovery. At Mt Isa, zinc recovery was increased by ten per cent by applying fine grinding to existing poorly liberated streams. In fact, grinding finer in the IsaMill actually improved the recovery of fine particles by ten per cent, and maximum particle flotation recovery occurs for 10 ¦m particles. A more recent example is the flotation of Platinum Group Metals (PGMs). The use of conventional ball or tower milling to improve liberation is severely limited by the impact of commonly associated chromite on classification, and degradation of flotation performance by the steel grinding environment. The ability of open circuit IsaMills to deliver a narrowly sized ultrafine product with clean mineral surfaces is transforming the design of platinum flotation circuits. The science and practice of fine-grained flotation is now thoroughly proven. The availability of the 2.6 MW IsaMill has made ultra fine grinding a practical tool for flotation plant design. It is expected to become a standard choice for future applications of both fine-grained ores and for minerals with difficult flotation characteristics.

Jan 1, 2005

By S S. Kanchibotla, S Morrell

In recent years there has been a growing recognition of the impact that mining practices have on the efficiency of mineral processing operations. Head grade, dilution, particle size distribution and their variability are known to have a significant effect on the throughput and recovery achieved in mineral processing plants. Improved process monitoring and modelling have provided the opportunity to identify and quantify some of these impacts and to define very significant incentives to optimise the overall operation from the mining face through subsequent comminution and processing. The Julius Kruttschnitt Mineral Research Centre has been undertaking research to optimise æMine to MillÆ performance through a major AMIRA research project and through individual research contracts with mining companies. This work has resulted in a broad range of field and laboratory experience in terms of both the challenges and the opportunities encountered when tailoring blasting operations to suit the overall æMine to MillÆ production chain. This paper describes the objectives of æMine to MillÆ blasting to optimise the system of rock breakage involved in the blasting, crushing and SAG milling of hard, brittle ores. The design of such blasts falls outside the conventional envelope of experience for most engineers and requires the consideration of some critical factors if the objectives of such blast are to be met and some of the potential problems are to be avoided. Experience to-date has also found that the quality of implementation is critical to the success of æMine to MillÆ blasts.

Jan 1, 1999

By H von Blottnitz, J L. Broadhurst

Eco-efficiency has been proposed by the World Business Council on Sustainable Development as an environmental performance indicator framework that contributes to sustainability by assisting corporate decision makers improve the environmental performance of their operations and processes, while also extracting additional economic value. Given that the recent engagement of the minerals industry with sustainability has highlighted the need for requisite tools and methodologies, it is therefore of interest to assess whether eco-efficiency indicators can drive sustainability performance improvement during process design within the minerals industry. Previous work indicates that the choice of sustainability performance indicators to be used for decision making needs to be governed by the decision context; ie the performance indicators need to be fit-for-purpose. Here, the strengths and weaknesses of eco-efficiency indicators are analysed using case studies. First, a more rigorous definition of eco-efficiency indicators for the minerals industry is proposed based on indicators currently offered in the literature. Two case studies are then selected to reflect typical decision situations encountered within minerals process design. For each case study, eco-efficiency indicators are computed and are compared to more traditional graphical representations of the economic and environmental performance of process design alternatives considered. The sensitivity of these indicators to various process design parameters is also investigated. Results confirm that the meaningful application of eco-efficiency indicators is strongly dependent on the decision context in which the process data is generated. Results also show that eco-efficiency indicators can be related to technical process design parameters to allow for richer communication of performance information for various decision trade-offs; however, in some cases, graphical approaches that provide more insights into the environmental-financial trade-offs should be preferred. The research thus contributes to guiding the selection of the appropriate tools for more environmentally sustainable design of minerals beneficiation processes.

Jan 1, 2009

By D S. Collins, Z Hosseini, I Pinnock, Y Toya

Microseismic monitoring is regularly used in the mining and geotechnical industries to provide detailed information about rock mass response to operational activities. This paper implements a variable 3D velocity model (VM) at a North American hard rock mine with the aim of further improving the accuracy of seismic event locations. A collapsing method is also used to help analyse two individual seismic event clusters at another North American hard rock mine. In the first case study, the location accuracy of events is shown to improve by moving from a conventional single VM to a variable 3D VM that accounts for voids and different geological domains. The modal average for the event location accuracy improved from 14 m to 5 m when the 3D VM was used. Additionally, the single VM failed to locate 26 per cent of the seismic events that were located by the 3D VM. In the second case study, the distribution of seismic events was further enhanced by using a collapsing method that highlighted planar structures. The collapsing method was performed on two large event sequences that occurred in close proximity and identified different seismic event distributions. One aftershock sequence aligned along a plane, suggesting an activated structure, while the other large event sequence had a more 3D distribution of events, suggesting a complex stress redistribution on smaller structures.CITATION:Pinnock, I, Collins, D S, Toya, Y and Hosseini, Z, 2016. Large event sequence analysis and 3D velocity models for seismic event location accuracy, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 879–884 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By T O Aspinall

The Australian mineral industry involves a diverse range of expertise and skills. Within that, the mining industry, representing mine planning, mine management and equipment operation, has capital intensive, high productivity equipment and a small but skilled workforce. Continuing education for all personnel in the workforce after formal school courses will be an important contribution towards improving competitiveness. The non-tertiary sector represents a significant proportion of the workforce and requires as much attention as the tertiary educated group. Competency Based Training is now being developed for the mining industry in Australia under the National Training Board and the mining industry is well represented in establishing standards and curriculum. TAFE is a major source of accredited courses but some mining companies are also developing internal courses not necessarily for external accreditation. Articulation of such accredited courses to tertiary mining engineering courses has been considered. The education and training of equipment operators through continuing education requires attention to operating skills, an understanding of the productivity factors under the direct influence of the operator and providing product quality to the customer. The education and training of mining engineers has been widely covered and continuing close involvement of the mining industry is required to ensure well balanced courses in technical and interpersonal skills as well as motivation to continue learning for life. Postgraduate research is a part of continuing education but the mining industry has to continually address the adequate recognition of post-graduate qualifications for the increased technical or management expertise and the development of better analytical and problem solving skills which can be directed towards improving competitiveness. More attention has to be paid to providing adequate financial incentives to attract suitable students, particularly after attaining some experience, and to address their professional career path with a company so they are not significantly disadvantaged by undertaking post-graduate studies. The Chartered Professional Engineer status as provided by The Institution of Engineers, Australia to qualified candidates is being considered by The Australasian Institute of Mining and Metallurgy as a further recognition of a member's specific expertise and competence in mining and metallurgical engineering. Continuing education plays a major part in the maintenance of the expertise and competence required for a professional engineer to develop and also to retain chartered status. Continuing education will be a significant part of the education and training of all the mining workforce towards improving the competitiveness of the mining industry. The major challenges will be the motivation of all towards lifelong learning and the integration of the various programs towards providing the opportunity for a steady and satisfying career progression.

Jan 1, 1994

By Z Tong, M Gao, X Wang

In response to the need for improved magnetic separators for beneficiation of fine grained iron ores that have been finely ground to liberate the iron minerals from the gangue, a series of high efficiency wet drum permanent magnetic separators (T-GCT) has been developed by Maanshan Tiangong Technology Co Ltd. These magnetic separators have high efficiency for separating superfine strongly magnetic minerals and the ability to produce high-grade concentrates with high recovery. They are ideal replacements for conventional drum magnetic separators, especially for treating superfine particles.

Jan 1, 2009

Against a background of deeper pits, the introduction of prestripping fleets and the need for closer control of operating costs (especially the waste removal component), Australian coal operations utilising draglines have in recent years become increasingly focused on:1. assessment of more efficient excavation methods; and2. application of explosive products and initiation systems which offer more flexibility than ever before.Additionally, developments in blast performance assessment techniques and equipment, and computer modelling and excavation monitoring systems have provided an improved opportunity to design a blast to achieve a desired profile suited to the excavation equipment and Sequence.

Jan 1, 1992

By T McConachy

New opportunities for miners are beginning to appear through new discoveries, improved knowledge and access to vast unexplored areas of the deep sea and continental shelf. Recent discoveries of undersea hydrothermal deposits show evidence of high-grade mineralisation, although in many instances the extent of the resource is still unknown. The promise and the difficulties of undersea mining have been evident since attempts were first made to mine manganese nodules in the 1960s. The physical nature of the undersea resource is a key influence on its mining potential; and environmental issues will also become increasingly important. This paper explores these issues and concludes with a description of the immediate to medium term applied research required to develop this industry and the spin off that such research can provide.

Jan 1, 2000

The introduction of rubber tyred diesel equipment underground in the early 1960's and subsequent design improvements to diesel haulage systems over the past 2 decades has meant that diesel truck haulage has often been the first choice when selecting a haulage system for a new underground mine. Even today only 9% of all vehicles underground are electric powered.However, with the development of more efficient electric haulage systems, the suc-cessful installation of low cost shaft hoisting systems and improvements in conveyor design, alternative haulage systems are appearing as viable alternatives to diesel truck hauling. In particular, the aspects of ergonomic and environmental operating conditions, maintenance and operating costs as well as productivity rates are becoming more and more important in the selection of underground haulage systems. Future develop-ment of existing diesel haulage systems will require that diesel haulage units become more productive, have considerably reduced exhaust emissions compared to existing units and remain the cheapest haulage method for under-ground one way haul distances up to a distance of 3 kilometres. Development of electric truck and associated fuel cell haulage systems

Jan 1, 1985

Reason Analysis of Impurity Containing and Technology Discussion of Quality Improvement for Low-Quality Iron Concentrate

Sep 13, 2010