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By Gilbert DJ, Lemon NM

A case history of a two year study of low grade ores in the Middleback Range area with the objective of defining possible areas of interest from a combination of geological- petrological-metallurgical criteria. Covering the general geology of the area and ore types; the results of metallurgical testwork and the pattern of evolution of these tests; the petrological explanation of the results of the testwork; the culmination of the work in the selection of areas of best potential for more intensive work. Jaspilites consisting of magnetite, hematite and limonite with quartz and silicate-carbonate-sulphide minerals are hosts to high grade iron mineralisation but also constitute a large low grade iron Reserve.

Jan 1, 1975

To reflect on the early history of mining in South Australia requires considerable imagination and rashness. The people who were the chief actors in the scene have long since passed away. Accounts of their activities are hazy and debatable. A broad brush account is all that I can hope to accomplish under these circumstances. It is fitting that a picture be painted and possible lessons learnt from the achievements of our pre- Decessors.

Jan 1, 1987

Conveyor belt haulage offers the advan tages of continuity of operation, minimum labour requirements, and the ability to handle large volumes of material over extended periods. However, breakdown of critical con- veyors in the system can cause undue and substantial losses in production output at the working faces, unless adequate surge bin capacity is incorporated in the haulage system. A conveyor belt simulation programme, code name 'Beltsim' was developed by Bucklen et al (1968) at the Virginia Polytechnic Institute in the U.S.A. and provides a quantitative measure of the performance of a conveyor belt network design. A limitation still exists with the computer programme and involves the inability of the programme to predict the necessary surge bin capacity to overcome conveyor belt downtime. The computer programme was modified to overcome this limitation, to simulate a con- veyor belt breakdown, and to provide a quantitative prediction of the surge bin capacity necessary to permit a modern mining system to operate effectively and continuously.

Jan 1, 1977

By Denholm W. T

The SMELT-2 package is specifically designed to perform on-line simulation of smelting processes. This paper describes its application to the simulation of continuous matte converting followed by reductive slag cleaning in SIROSMELT reactors. The matte, containing 50% Cu is assumed to be produced at the rate of 20 tph in a continuous matte smelting furnace such as an Outokumpu Flash Furnace, Noranda or Sirosmelt reactor. Two alternative fluxing strategies in the converter are examined, namely: ò conventional silicate slags, ò calcium ferrite slags, and the flow sheets associated with each strategy are discussed. A regular solution model is used in the present study to account for the variations in the activity coefficients of components in the slag.

Jan 1, 1989

Trial ore production began at the Hilton Mine in 1987 with ore being trucked into Mount Isa for treatment at the Lead/zinc Concentrator. The expansion of output from the Hilton mine required additional concentrator capacity which led to the design and construction of the Hilton Concentrator. Systematic laboratory and Pilot Plant testwork dating back to 1968 to develop a flowsheet and reagent regime suited to the varied and generally complex mineralogy of the Hilton ore was successfully concluded with a Pilot Plant trial using a sulphoxy based sphalerite depression system in early 1988.In May 1988, a decision was made to build a 750 000 t/y concentrator with some novel technological and capital-efficient features. The Hilton Concentrator commenced operations in December 1989 reaching target grinding rates and metallurgical performance by mid-1990. Current ore treatment rate is 800 000 t/y.Lead concentrates assaying 43 - 48 per cent Pb are combined with the Lead/Zinc Concentrator lead concentrates and smelted at Mount Isa. Zinc and Low Grade Middlings (LGM) concentrates are filtered in the zinc filter plant at Isa with those from the Lead/Zinc Concentrator and then railed to Townsville for export or treatment in Australia.

Jan 1, 1993

This paper concerns a pragmatic approach to a problem that is common to many operations in the mining industry: how, over the short-term, to grasp the extent and distribution of long-term financial risk from environmental causes and reduce these risks strategically, in order to maintain stability and flexibility in the operations. Surprisingly, many companies operate without an environmental master plan or tools that can help managers measure and reduce financial risks. Such companies may be subject to unknown unacceptable financial risks from environmental causes. While many companies have some kind of internal system of environmental standards, it is often the case that such systems have uneven or limited effect, and offer no opportunities for visualising, measuring or managing aggregate financial risks from environmental causes. `Aggregate risks' are defined here as the calculated total expected financial costs to a company, or a subdivision of a company, from environmental causes at nominated operations over a defined time period. Aggregate risks take into account the type and magnitude of an environmental problem set, the likelihood of occurrence, and the time frame during which the problems will develop or solutions are required. For the large corporation, the 'amount of' aggregate environmental risk is a statistic that can be managed, along with other financial parameters, at the corporate level to improve the stability and predictability of operations, and protect the interests of shareholders. This paper concerns development of a management framework and a tool for the large corporation that responds to the need for managing aggregate environmental financial risks. The logical framework proposed to overcome the need for strategic vision is the Environmental Master Plan, and this is described in the next section. The analytical tool proposed to measure aggregate risks and provide relevant data and insights to managers, is called an Environmental Risk Management Information System, and its mechanics are described in a subsequent section.

Jan 1, 1994

The BHP Billiton Cannington mine uses sequential flotation to treat a silver, lead and zinc ore supplied from an underground mine. The final products from the process plant are a silver rich lead concentrate and a zinc concentrate. Operational history of plant performance highlighted that the majority of valuable metal losses to final tailing occurred in the -5 ¦m fraction. Research completed on the flotation characteristics of this size fraction in plant feed resulted in the development of a split flotation process to improve the silver and lead mineral recoveries. Construction of a $A 9.5 million brownfield project to install the new split flotation circuit at Cannington was completed in July 2002. The circuit consists of three stages of cyclone classification to recover the ultra fine material to a final cyclone overflow stream, conditioning of this pulp to achieve optimal process conditions, and conventional rougher and three stage cleaner flotation to produce a silver rich lead concentrate. The rougher tail from the new circuit is recombined with the cyclone underflow streams and processed through the original lead-zinc flotation circuit. This paper discusses the circuit design, material properties, material selection for components of the circuit, operational practices and requirements to ensure the circuit succeeded in meeting production targets. The technology is subject of a number of patent applications including international application No PCT/AU02/00400.

Jan 1, 2003

Subsurface development requires some geotechnical conditions and challenges. Most of then are related to the compatibility between tunnelling system and surrounded ground conditions, and design criteria. Design criteria usually involve lining pressure and ground control of displacements. In order to fulfil these requirements, geotechnical parameters have to be obtained as well as construction aspects have to be taken into account for predicting the tunnel behaviour. The Brasilia Metro is presented as a case history illustrating the geotechnical conditions and challenges for its implementation. It is 42 km long, including tunnels excavated in collapsible porous soils by the New Austrian Tunnelling Method. The Brasilia porous clay presents some characteristics, which may lead to large deformations due to structural collapse. Empirical methods were calibrated for collapsible porous soils and then applied to predict tunnelling-induced settlements. Settlements due to soil structural collapse modify completely the expected settlement profile, increasing their values from the tunnel crown to the ground surface. Consequently, surface settlement trough volumes were also greater than the ground losses around the tunnel. In this case history, structural collapse of porous soils played an important role and must have been taken into account to predict correctly the settlement trough and profile. Numerical simulation has shown that settlement magnitudes due to structural collapse are strongly dependent on the soil stiffness reduction after collapse and the extent of the collapsible zone.

Jan 1, 1999

The mining industry has been slow at adopting the latest management philosophies from other industry sectors, such as manufacturing, and in retrospect, with good cause. With the plethora of three-letter-acronyms such as TQM, JIT, TPM and now, BPR each touted as the panacea for profit improvement, you wonder if you must choose one or attempt to embrace them all! In truth, each new insight into organisational behaviour bears some investigation. This paper looks at the underlying principles and elements of successful change strategies, and how several mining companies, including coal mines, in Australia, Chile and Canada, are applying these principles to their operations. These examples illustrate the need to think radically, and to view mining as an overall process delivering value to the customer rather than a collection of functional silos. They also show that often, a continuous improvement initiative is not enough when a fundamental redesign, a paradigm shift, is needed for a performance breakthrough.

Jan 1, 1998

Safety bulletins and stickers issued for the paste backfill plant at Cannington read as follows: æCannington Paste Fill Plant, First of ItÆs Kind in AustraliaÆ. We could even dare to state that the Cannington plant is different than any other paste backfill plant in the world because of the overall design, plant equipment and underground delivery. However, one thing to be certain of is, the paste backfill plant works as designed and a pump is not required to deliver paste underground given the general plant arrangement at Cannington. The past two years have been a process of evolution to design and construct the plant and make it work. This paper will describe the paste process using full mill tails along with placement of cemented paste underground. Discussions will include rationale of fixed plant selection along with various control requirements. BHP World Minerals recently commissioned its paste backfill plant in December 1997. Cannington is placing full mill tails underground via two surface boreholes that deliver either to primary or secondary stopes.

Jan 1, 1998

By P Minkkinen

"Pierre Gy showed in his early works that the results in estimating the variance of the mean value of continuous lots depends on sampling mode (random, stratified or systematic), except in the theoretical case that the measurand is randomly distributed in the lot. The experimental variance estimate calculated from samples taken from the lot is independent of sampling mode but depends on sample size and the type of the lot heterogeneity. Variography can be used to estimate the variance of the lot mean for different sampling modes.Gy also defined weighting error, which is made if a simple average is calculated from the assays of samples taken from a continuous object (eg from a process stream) where the flow rate varies with time and is correlated with the concentration of the analyte in the stream.The effect on sampling uncertainty of the three sampling modes and their interaction with the following factors in estimating the uncertainty of the mean concentration is studied using simulated lots, and lots having heterogeneity patterns similar to those of real data sets, including the effect of: the type of heterogeneity (random, grading and clustered heterogeneity patterns) increment size and number employing composite sampling weighting error. CITATION:Minkkinen, P, 2017. Dependence of the variance of lot average on the sampling mode and heterogeneity type of the lot, in Proceedings Eighth World Conference on Sampling and Blending, pp 319–330 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

May 9, 2017

By Paine GG

The in-situ retorting of shallow oil shale deposits is an attractive alternative to the material handling problems of conventional open pit mining techniques, which involve removing overburden, fragmenting and transporting the shale to a fixed retort, and finally disposing of the hot spent shale.For in-situ retorting to be successful, the oil shale has to be fractured and the fragmented rock expanded into a void, to allow controlled propagation of a flame front through the in-situ retort. The principles of cratering with explosives have been used to develop a process for the in-situ fracturing of a thin oil shale deposit overlain by a formation of porous rock. The overlying porous rock formation is first compressed by explosive charges to create voids in the porous rock. The oil shale is then fragmented and pushed in to the voids with separate explosive charges. This paper discusses methods of creating voids in porous rocks with minimal surface disturbance, and then methods of obtaining the most uniform fragmentation of the shale. The whole process can be completed, in practice, in one blast. The results of an experimental blast are presented, and possible modifications are then discussed.

Jan 1, 1985

By P J Savory

Ranger is a uranium mining operation located within one of the most environmentally sensitive regions of Australia. Geology has played an important role in mine planning, operations and rehabilitation since discovery of the deposits 25 years ago. The Ranger orebodies have a reserve total of 166 300 tonnes of U308 including 90 400 tonnes of U308 at North Ranger. At current milling rates these reserves give a mine life greater than 40 years. The uranium is hosted in Lower Proterozoic rocks of the Cahill I ormation and is associated with strong chlorite alteration. In pit grade control involves the use of calibrated probes and a radiometric truck discriminator allowing fast, accurate grade determination of material. Ore is defined at a cut-off grade of 0.2 per cent U308. Mineralised material is defined by the Uranium Mining (Environmental Control) Act 1979 (UMEC Act) at a grade of 0.02 per cent U30s. Natural water levels in the #1 Pit area vary as much as 7.5 metres between wet and dry seasons. Ground water inflow into the pit during the dry season is 600 m3/day. No significant slope failures have occurred in the pit. The environmental impact of mining operations is constantly monitored. Rehabilitation of non-mineralised stockpiles is ongoing. This paper discusses the interaction between geology, hydrogeology, rock mechanics and grade control with the present mining operation.

Jan 1, 1994

By J Brisebois

The derelict Lake George Mine is located at Captains Flat in NSW, acommunity of approximately 450, which lies some 43 km southeast ofQueanbeyan. It straddles the Molonglo River, which flows toQueanbeyan and thence the nationÆs capital, Canberra. Catastrophictailings dam failures in 1939 and again in 1943 resulted in the transportand dispersion of thousands of tonnes of sulfidic wastes downstream,with terminal settling in Lake Burley Griffin, in Canberra. The mine wasclosed in 1962, and major rehabilitation in 1996 - 1997 addressed the riskof further collapses, and reduced water flow into the underground mine.Nevertheless, acid mine drainage from the mine, and seepages ofcontaminated water from the capped tailings dumps continue to pollutethe Molonglo River for some 30 km downstream.Environmentally, the highest contributor to the total contaminant loadof the river is the Main Adit Spring. This was shown to be a constantgroundwater-driven acidic flow, with contaminant generation resultingalmost entirely from the ingress of gaseous oxygen into the undergroundworkings. Long term remediation may be possible at source, by pumpingreducing gases into the sealed mine, but the probability of thistechnology succeeding to the required degree is yet to be demonstrated. For at least the medium term, treatment of contaminated water flow(s)will be required to achieve any of the water quality targets that may beapplicable to the river. Three methodologies were short listed, but anumber of strategic uncertainties remain, which the NSW Derelict MinesProgram will address. Future risk arising from long-term contaminantrelease by the treatment wastes must be considered. Appropriate data,and realistic long-term performance parameters regarding the relativestabilities of water treatment sludges are scarce, and make properevaluation of competing technologies problematic.

Jan 1, 2003

Despite the research interest on non-cyanide gold lixiviants over the past three decades all the non-cyanide gold processes are still at the developmental stages with limited understanding on solution and pulp chemistry in some cases. This is partly associated with:the difficulties in measuring reliable equilibrium data for various gold(I/III) complexes with non-cyanide ligands; the lack of knowledge on mixed-ligand complexes; and different kinetic stabilities of gold(I) complexes with respect to disproportionation. This paper presents reliable equilibrium data for complex formation, dissolution, precipitation, hydrolysis and disproportionation reactions of gold(I/III) compounds with a range of non-cyanide ligands: S2-, HS-, S2O32-, SO32-, SCN-, SC(NH2)2, OH-, NH3, Cl-. Solubility of gold(III) compounds with non-cyanide ligands follows the order: Cl- > NH3 > OH-. In the case of gold metal the solubility order at a given temperature is MgS > Fe(III) or Cu(II) / Cl- > Cu(II)/NH3 > NaOH, but the solubility increases with increasing temperature. Rate of gold oxidation with different non-cyanide lixiviants depends on the oxidant, ligand and temperature and follows the general order of oxidants: Fe(III) or Cu(II) > X2 or OX- > O2 (X = halogen). In the case of metal ion oxidants oxygen is required to reoxidise Cu(I) or Fe(II). Some of the reported data on chloride and thiosulfate leaching of gold are presented to highlight the effect of additives and the copper, silver and sulfur contents of the starting material on the success of non-cyanide leaching processes.

Jan 1, 2004

By S W. Kingman, D Whit, I S. Lowndes

The use of compressive crushing equipment such as gyratory crushers within minerals processing plants can potentially generate large quantities of dust. Remedies to this problem include the retrofitting of shrouds, enclosures, local exhaust ventilation (LEV) systems and water suppression systems. The single or combined application of these systems must be optimised to ensure they operate efficiently. It is desirable that the future design planning of such facilities include integrated dust suppression and/or removal systems to ensure material delivery rates are maintained and the welfare of the workforce is protected. The characteristic release of dust and the disturbance to the surrounding ventilation airflow is investigated by the construction and solution of computational fluid dynamic (CFD) models validated by data obtained from scale experiments. A 3D computational model was constructed using the FluentTM CFD software to represent the background ventilation regime within an underground crushing installation. The falling ore is represented as a continuum granular fluid falling under gravity from the raised bed of the dump truck. Transient path lines are computed to simulate the updraft airflow generated by the tipping process and indicate the dispersion path of any entrained dust. The relationships between the falling ore material, the displaced air and the shear induced flow are determined by an analysis of the computed volume/mass flow rates predicted across the crusher opening. An analysis of the airflow patterns predicted by the CFD simulation models indicates strong shear flows induced between the tipped material and the surrounding airflow in the vicinity of the crusher during tipping, and a strong influence of the background ventilation regime on the path taken by this shear flow. Scale experimental studies were conducted to characterise the induced shear flow and visualise the potential entrainment and transport of dust. An analysis of these experiments is presented.

Jan 1, 2005

Anglo Platinum recognised with its expanded operations the need to change its evaluation strategy due to increased sample volumes and the pressure it created at laboratories. The sender/receiver analytical scenarios had to change in order to curb costs and to prevent substantial investments in new sampling and analytical facilities. Given the high cost associated with correct sampling systems and sampling protocols and the shortage of technical resources a strategy of single point sampling and analysis was introduced. The analysis was then done at an ISO17025 accredited laboratory with ten per cent checks, subjected to careful statistical scrutiny. Logistical problems increased with respect to weighbridge congestion, maintaining sampling quality, throughput of samples in the sample preparation areas, manual quality control systems in place, audit trails and analytical capacity throughout all operations. This required the expedited improvement of existing sampling practices and the development of new sampling methods and equipment. Anglo Platinum is classifying and standardising sampling equipment, sample preparation and analytical procedures for all process streams with the view to minimise overall uncertainties. Major investments were made into a customised LIMS and automated equipment for data management, reduction of manual transcription errors and streamlining of sample processing. Anglo Platinum is committed in rolling out the enhancements to all sites as priority dictates.

Jan 1, 2008

By Wilkinson LR

The object of this paper is to present a brief overview of applications of radioisotopes in mineral processing. The emphasis is towards on-line applications, and is to present the broad picture rather than become involved in the details of particular applications. For a more detailed and comprehensive coverage, the reader is referred to the International Atomic Energy Agency International Symposium on Nuclear Techniques in Exploration, Extraction and Pro- cessing of Mineral Resources, held in Vienna 7-11 March, 1977. Because of space limitations here, we have inmost cases restricted coverage to those applications of radioisotopes within the direct experience of Amdel and Australian research bodies. Radioisotopes spontaneously emit energy in tiie Form of a and S particles, and electromag- netic radiation. The electromagnetic radiation is generally referred to as y-radiation when it originates from the nucleus, and X-radiation when originating from the electrons orbiting the nucleus. X-ray and y-ray energies overlap, with X-rays extending from a few electron volts (%') up to about 100 keV. Gamma rays in the useful energy range extend from a few keV up to .feV.

Jan 1, 1978

In many metal mines in China,the 70B2 series of fans has been used for main fans for a long time.These fans generate higher static pressures than are required for the relatively high equivalent orifices of the ventilation systems of many of the mines. As a consequence, their running efficiency is common only around 30%. The loss of power is significant.

Jan 1, 1988

By A G. Grice

Surface disposal of mining processing wastes is usually perceived as an undesirable consequence of meeting societyÆs needs for metals and minerals. Environmental disasters associated with the discharge or storage of such wastes, though infrequent, can have very damaging consequences for the environment and the industry. Reducing or eliminating the potential for such events may be achieved by placing some or all of these processing wastes back into the voids created by the mining operations. Processing operations may limit or enhance the opportunities for using tailings and other waste products as a backfill material. Backfilling is a truly multi-disciplinary process and requires the informed involvement of mining, metallurgical, engineering and environmental specialists. This paper describes the range of fill types currently being used in Australian mines, particularly those utilising processing wastes as constituents. It focuses on how processing operations can affect the suitability of these materials for the various types of fill, the resulting fill properties, fill performance and costs.

Jan 1, 2002