Search Documents

By Shoobridge PH

Operating difficulties during 1977 with the Imperial Smelting Furnace operated by Sulphide Corporation Pty. Limited at their Cockle Creek zinc-lead smelter were found to be caused by premature softening of sinter in the upper shaft of the furnace. This soft- ening was shown to be a consequence of raw materials and operating policies which led to unusually high levels of both lead and silica in a sinter of low basicity. A programme of softening tests and micro-examination of a range of sinters established that premature softening occurred when lead and silica increased to the point where a lead-calcium silicate with a low lime content became the major continuous phase in the sinter. This information was used to define a range of compositions which kept the softening temperature acceptably high for furnace operations.

Jan 1, 1978

It is a very great privilege for me to be able to address you tonight and I am deeply sensible of the honour which has been done me. I am equally sensible of the inadequacy of my training for the position of President of your Institute.May I say at once what a very great pleasure it is to have so many members from the mainland States visiting us here in Tasmania. We do hope that you will find pleasure and profit in your stay.Since the Annual Conference is always held in the vicinity of one or other of the great mining fields, it has become the practice for the Presidential address to review the history of the particular field and t(j) indicate its place in the economic structure of the country.I propose to follow this practice and to try and present to you a short picture of thÇ mineral industry as it has existed in Tasmania. None of the information is new it is available in diverse and remote geological reports and in publications such as Witham's Western Tasmania and the more recent Peaks of Lyell. The last composite approach was written twenty years ago by P. B. Nye and published as a Geological Survey Bulletin.I have enjoyed preparing this address because on occasion I find it refreshing to look back and see what was known and what was accomplished in the days when the going was a little tougher than it is now, and to speculate upon the reasons that drove men to do what they did. I shall therefore discuss the search for minerals in this State; the discoveries over the years; the elation with which the new fields are greeted; the disappointments attending some of them; the mines that have come and gone; and the...

Jan 1, 1958

The paper describes the design of the dilute medium and medium recovery circuits installed at the coal preparation plants at the Cornwall Coal Company's Fingal Mine, and the BP Coal Australia's Howick Mine. These circuits maximize the use of clarified water for rinsing to improve the mass transfer of adhering medium from the coal surface into the carrying liquid, and have been combined with the use of a two stage magnetic separator. The separator utilizes a conventional concurrent first stage and a counter-rotation second stage. This combination results in high medium recoveries during both normal operation, and start up and shut down phases when large quantities of medium can be lost from a conventional circuit. Overall losses using this circuit have been estimated to be, 200g/t, over a twelve month period. Further advantages in plant operation are also obtained, especially steady operating conditions in the centre-tube pump tank, lower slimes contamination of the product, and lower quantities of non magnetics trapped in the separator concentrates. The techniques are particularly suited to incorporation in circuits treating coals containing high percentages of sticky and difficult clays, as are found in the Walloon coal measures.

Jan 1, 1987

By J Zhang, R Dimitrakopoulos

A two-stage stochastic mixed integer non-linear program is formulated for a mining complex to optimise strategic and tactical plans. The objective is to find the near optimal decisions for a mineral supply chain in the context with uncertainties in both ore supply and the commodity market (price and demand). The endogenous spot price in the commodity market and long-term sales contracts are considered in the formulation of the mining complex’s optimisation model and an ad hoc heuristic is developed to deal with the throughput – and head-grade-dependent recovery rate in processing plants. Numerical results indicate that the proposed heuristic is effective and efficient in numerical tests. Based on the proposed model and heuristic, a long-term contract design strategy is proposed for making decisions on the contract price and strategic investments. A shadow price based method is also proposed to evaluate the existing mining schedule.CITATION:Zhang, J and Dimitrakopoulos, R, 2014. Optimising a mineral supply chain under uncertainty with long-term sales contracts, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 25–32 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By E Giles

Pike River Coal Limited (PRCL) is opening a new underground coal mine in the Paparoa Ranges north-east of Greymouth. To access the coal reserves, PRCL have had to build a 13 km access road through regrowth and virgin forest, and appointed McConnell Dowell Constructors Limited, with URS New Zealand Limited as their consulting engineers, to construct the final access link: a 2.3 km long, 5.5 m wide and 4.5 m high incline tunnel. This paper discusses the logistical issues of construction in an isolated pristine forest in mountain land and how they were addressed. It provides an overview of the 90 per cent complete tunnel and how challenging rock conditions have been mastered. It outlines briefly the remaining work which is construction of pit bottom workings where the mine infrastructure will be housed and construction of a 110 m deep, 4.0 m diameter, vertical ventilation shaft.

Jan 1, 2008

By G Danckert

The key technical theme of ‘orebody knowledge’ has been applied by Rio Tinto in the Pilbara iron ore precinct from 1966, when operations first started there. It forms the basis of present day application, as well as planning for the future.This paper will review how the early towns and mines commenced and how they formed the basis of Rio Tinto’s early operations, on which the Pilbara precinct has been based. A profile of the last decade of Pilbara growth will be highlighted, together with the current integrated network of mines, rail and ports and the next generation of expansions.The paper will specifically describe the Rio Tinto process of significant resource evaluation, including comprehensive drilling programs and the conversion from resource to reserves. It will also describe the overall mine planning process, both from the strategic view, as well as for short-term mine plans.The ability to innovate in resource development will be discussed. This will include not only the technical dimension of changing cut off grades, use of low-grade ores and managing low-grade stockpiling and beneficiation, but also the broader application of new technology and innovation in the iron ore business.

Jul 11, 2011

By G P. S Resende, D E. G Oliveira, E A. S Baeta, T F. Bravin

There is currently in the mining industry, as well as in other industries, a movement seeking to increase investments in decarbonisation processes to help combat global warming. Among some initiatives taken is replacing diesel-powered mobile equipment in the mines with electricity-powered equipment, such as electric off-highway trucks or even belt conveyors in the mining operation. Samarco is a Brazilian mining company that since its conception has used a conveyor belt mining system in its mining operation, using only a small number of trucks to complement the mining process. This mining process that combines conveyor belts and trucks has brought environmental gains for the company since the environmental impact of conventional truck-only mining is greater than that of the combined system. To measure these gains, a medium-term mining plan was developed in which two fleet scenarios were detailed. One scenario contemplated a high level of detail of belt mining seeking its maximisation, while the other considered the operation performed 100 per cent by trucks, eliminating the use of conveyor belts. Through the comparison of these two scenarios, it was possible to make an inventory of atmospheric emissions and greenhouse gases for each one of them considering data such as types of equipment, diesel consumption, total distance travelled and energy consumption. The results showed that the fleet scenario with conveyor belts results in periods with up to 15 per cent less greenhouse gas emissions and 37 per cent less total particulates compared with the truck-only scenario. Therefore, the results confirm the environmental benefits of the method and the need to look for ways to even expand it in future operations through a study to identify the potential areas in the long-term mining plan.

Sep 18, 2023

By T Baumgartl, D Bradshaw, B Forsyth, M Edraki

In a tailings storage facility, the chemistry of pore water is a function of oxidation and dissolution of sulfide minerals, containing metals and metalloids, the neutralising effect of gangue minerals and the geochemical processes controlling solute equilibria such as pH, redox potential, precipitation, ion exchange and adsorption. On the other hand, the changes in geochemical composition of tailings feed over time is a function of spatial variability within the orebody and modifications in processing method. Tailings properties such as pyrite content, pH, concentration of deleterious elements, surface chemistry, pore water chemistry and particle size are already shaped in the dynamic environment of a process plant.To engineer desired environmental outcomes, a new research framework is needed. The new approach should follow the physical and geochemical processes of tailings feed and construct models that can be used for the prediction of seepage water quality and dust propagation and evaluate the potential re-processing of tailings or production of tailings with desirable surface chemistry, particle size and internal structure. The challenge of developing tailings engineering model is not in laboratory techniques, but more of the overall communication of results and establishing the link between disciplines. It requires investigating geochemistry across mining and processing for improved environmental outcomes at tailings storage facilities.The paper reviews the current tailings management practices by comparing the geochemistry and mineralogy of tailings and the chemistry of seepage water from three Australian case studies in the context of geology, mineral processing and climate. Some alternative methods of tailings management are also reviewed and it is concluded that a proactive multi-disciplinary approach is needed with respect to tailings management, based on a novel integrated research framework.CITATION:Edraki, M, Forsyth, B, Baumgartl, T and Bradshaw, D, 2012. Geochemistry of tailings and seepage from three tailings storage facilities in Australia - Uncapped, capped and active tailings, in Proceedings Life-of-Mine 2012 , pp 269-278 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By Rabie A. S, Fouad K. M, Ammar A. A

The existence of Gabal El Kahfa ring complex, located in the Eastern Desert of Egypt, has been ascertained from aeromagnetic and aeroradiometric survey data as well as by aerial photography. Two maps for -the net aerial radiometric measurements reduced to ground level and aerial magnetic data corrected for the regional normal gradient of the earth's magnetic field have been constructed. The aeroradioactivity data have been interpreted geologically and analyzed statistically to outline various radiometric units and compute their charac- teristic statistics. The ring complex showed a circular radiometric feature and yielded a radiometric mean background and a standard deviation of 6.48 and 0.89 pR/h respectively. Besides, the observations showed a normal distribution. The aeromagnetic data have been reduced to the north magnetic pole, then filtered to produce the regional-and residual-component maps. Statistical trend analysis was conducted for the tectonic linea- ments resulting from the three magnetic maps, to define the structural framework of the area under study. This statistical study proved the exis- tence of trends in the east-west, northwest-south- east, northeast-southwest and north-south directions. The ring complex is characterized by a circular magnetic feature, whose average relief is 2150 nT. It is included within a high east-west trending magnetic zone. The latter represents a deep-seated uplift or anticline which is bordered from all sides by some faults of different trends.

Jan 1, 1988

By B L. Sommerville

"The theme of this International Mining Geology Conference is ‘Setting New Standards’. Rio Tinto’s iron ore operations include a complex integrated supply system to deliver ore from 15 mine operations through four independent terminals over 1700 km of rail line. Significant growth in the past 20 years has seen production grow from 88 Mt in 1997 to 329 Mt for the 2016 calendar year.With more than 50 years of mining in the Pilbara, Rio Tinto has extensive experience in developing standardised approaches to mine geology and the geometallurgical prediction of product quality to meet the increasing growth profile and business planning complexity.Rio Tinto’s standardised approach to mine geology can be developed and utilised on a daily basis to enable the optimisation of the supply chain in terms of tonnages and product quality. This experience demonstrates a fully standardised system can balance the needs of a systematic process across all mine sites and the flexibility for mine geologist to determine and use local properties at each mine; this is done by ensuring two key principals are in place: a single, centrally maintained, system is established and maintained, providing a common set of processes and software across all mine sites the system allows senior mine geologists to review and customise key attributes and product regressions, ensuring site specific data is used in product predictions.The benefits of formal work process and standardisation include health, safety and environment, people and skill development, cost and improved communication. Also product predictions from mine geologists are one of the key inputs into an integrated and dynamic mine to ship scheduling system, optimising the supply chain whilst still managing the product quality. The experience of Rio Tinto is that a standardised approach to mine geology is an enabler of value for the iron ore operations.CITATION:Sommerville, B L, 2017. Mine geology standardisation – providing the foundation to consistent short-term geometallurgical product predictions in a complex multimine and supply chain environment, in Proceedings Tenth International Mining Geology Conference 2017, pp 13–20 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 20, 2017

By G R. F Alvear Flores

Mineral resources are becoming more complex in composition and structure making it more difficult to produce clean concentrates for primary metal smelting. In parallel, providing technological solutions to the recycling and recovery of end-of-life materials is becoming more important in moving towards the goal of increasing circularity. The availability of fundamental thermodynamic data and advanced thermodynamic tools greatly assists in evaluating these complexities and their impact on existing and new processes. In addition, it is fundamental to support the economic performance of smelters. This paper describes several examples on how fundamental work can be applied to industrial processing..

Jun 17, 2024

By McHaina D. M, Hardcastle S. G

A description is given of an investigation into the feasibility of using controlled recirculation of warm exhaust air into the cold intake air of underground mines during winter. Canadian mines can experience inlet air temperatures of minus 30 ¦C and less, requiring them to pre-heat their intake air. The use of controlled recirculation would reduce the inlet air quantity and thus reduce heating costs which exceed $1M on some mines.

Jan 1, 1988

By Takasaki Y, Ohzeki S, Hotta H

TO measure high temperature properties of blast furnace burdens ( the change of gas permeability accompanied by contraction, soft- ening and melting ) which govern the gas flow and its distribution, a series of experiments were carried out under simulated blast furnace conditions, using sinter, acid pellets and self -fluxing pellets. 1) The high temperature properties are affected by the ore's reducibility ( up to 1000 -1200¦C ), and the composition, and volume of gangue before reduction. Generally, the burde- ns with high basicity ( Ca0/Si02 ), high reduc- ibility and low volume of gangue have good high temperature properties. Good high temperature properties are : a high temperature at which the gas permeability rapidly decreases, a high melting point and a low maximum pressure drop. 2) Using acid pellets, slow-down of red- uction rate occurs around 1000¦C because the pellet forms a dense metallic shell, while its slag core, resulting from a FeO, Si02 and A1203 reaction, has a lower melting point. 3) The addition of MgO sources improves high temperature properties both of sinter and Pellets.

Jan 1, 1980

Ore sorting is a high capacity, low cost method of preconcentrating ores and in some cases of producing a marketable concentrate. In most cases it is applied to run of mine material, immediately after primary crushing and screening in sizes ranging from 10 mm to 150 mm. Recent developments in bulk sorting of friable uranium deposits have resulted in machines capable of handling fine materials with sensing and separation being achieved on a zone by zone basis. Modern ore sorting machines rely on the synchronous operation of four internal sub systems, feed presentation, sensing, data processing and separation. A variety of different sub systems is available which can be combined in various forms to produce sorters capable of handling a wide variety of mineral types. The benefits in using ore sorting cover a wide range of situations and are applicable to both established mines as well as new mining ventures. Reduced operating costs, increased productivity, capital savings, energy and resource conservation and environmental issues are all part of the reason why ore sorting is finding rapid acceptance in today's mining industry.

Jan 1, 1980

By S H. Algie, D P. Taplin, S G. Doig

"Suboptimal performance of clusters of hydrocyclones (cyclones), relative to the performance of the individual cyclones that comprise the cluster, is a common phenomenon. The primary cause is well known: uneven distribution of the slurry feed into the individual cyclones. The direct result of uneven distribution is that each cyclone in a cluster performs somewhat differently. Hence, some, if not all, of them do not work at their intended operating points, and the classification is not as sharp as intended. The impact on grade, recovery and milling efficiency will vary depending on the duty of the processing circuit, but the most immediately apparent consequence of uneven distribution is a difference in wear rates in the individual cyclones; this exacerbates the problems of unequal performance of the individual cyclones. In severe cases, and as differential wear proceeds, flows from the individual cyclones may become visibly different. Uneven distribution, once the phenomenon was identified, was seen to be a significant issue in the high-solids hydrocyclone cluster in the ball mill recycle section of Evolution Mining’s Edna May Operation (EMO, Westonia, Western Australia) gold processing plant. In 2012, a FloCEP® hydrocyclone feed distributor system was installed to alleviate the problem. Over the next four years of operation, this innovation has proven its value in the metallurgical and maintenance areas. Individual cyclones now wear at the same rate, greatly reducing the need for operator intervention, as well as increasing overall plant availability through minimising unplanned maintenance. The costs of the installation can be justified by savings in maintenance alone, though the greatest value, as is described in this paper, is in allowing the plant to produce consistently closer to its operational design limits. The FloCEP® system is a low maintenance, readily installed retrofit, based on two patented devices that are combined with complementary proprietary design methodology allowing customisation for specific flow rates and slurry particle properties. Together, these devices produce and distribute a pseudo-homogenous slurry flow without moving parts.Citation:Taplin, D P, Doig, S G and Algie, S H, 2016. Experience with FloCEP® Slurry Flow Conditioning at Evolution Mining's Edna May Operation, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 251–260 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By D H. Bell

Slab-buckle failures in coal sequences involve thin slab deformation in strata dipping parallel to the footwall, and are a consequence of both unloading and the weak nature of the thinly bedded rock mass. Methods of modelling and predicting such occurrences include: +        a conceptual model using a base friction table, +        a mathematical model using the Euler solution for column and beam bending (after Goodman, 1980), and +        computer analysis techniques such as UDEC (Universal Distinct Element Code after Cundall and Hart, 1993).   Slab-buckle failures have the potential to seriously disrupt production because of their volume and rapidity, and to endanger both equipment and personnel working on the pit floor.   In July 2004 a large slab-buckle failure occurred overnight after a new batter and bench had been formed at the Malvern Hills Opencast Mine in inland Canterbury. This involved the entire length of the pit (85m along strike) when a 2m thick intact slab with a total volume of ~3500m3 translated down dip 6.2m on the base of a thin coal seam to form a pronounced buckle at the toe. The coal measures consist of finely laminated mudrocks with multiple coal seams of varying thickness dipping ~45¦ to the southeast, and the opencast mine had been designed with footwall batters formed parallel to bedding with a vertical bench separation of 15m.   Back analysis of the Malvern Hills failure was necessary to investigate the controls on footwall instability, and for future mine design. An engineering geological model was created and samples of the slab material and failure surface were collected and tested to establish the required parameters for use in the Euler solution for column and beam bending. Back analysis using the Euler solution provided unrealistic results that overestimated the overall length of a stable slope by more than 10 times.   No further large scale slab-buckle failures have developed at the mine site, in part because of the slow rate of coal extraction, but precautionary drainage of the footwall slopes has been undertaken to improve overall batter stability. The location of the slab-buckle failure on a critically positioned pre-sheared thin coal seam with full hydrostatic head is considered the most probable cause of the July 2004 failure, rather than inherent instability of the generic bench and batter arrangement adopted. The use of a precedent-based engineering geology approach to future mine design is considered the most appropriate solution in the circumstances.

Jan 1, 2007

By P Dowd, R Jeuken, C Xu

In Australian coalmines there are a number of coal quality parameters that are measured by analysing samples from boreholes. The data points are used to generate spatial models of these parameters, typically using inverse distance as an interpolation method. Numerous additional boreholes are drilled which have geophysical logs measured downhole but from which no coal quality samples are taken. Full suites of coal quality analyses are expensive and time consuming to drill and sample. If geophysical proxies for coal quality could be used, this would greatly improve the accuracy of the resource estimation without additional cost.This paper examines two of the most important coal quality parameters – ash and volatile matter – and assesses the results of a number of geostatistical interpolation methods. The aim is to improve the accuracy of the interpolated models. Auxiliary variables from geophysical logs are also trialled to improve the estimation.A multivariate analysis of ash, volatile matter and several auxiliary variables of a selected coal seam was undertaken in a spatial context, using variography. This was used to construct a model of co-regionalisation that relates all of the variables as manifestations of an underlying geological theme.The traditional inverse distance interpolation approach was compared to ordinary kriging, universal kriging, co-kriging, regression kriging and kriging with external drift approaches. The relative merits of the six interpolation methods were compared by removing all points, one at a time and estimating at the thus known location. The mean error and the root mean square error were evaluated as a measure of bias and precision.This paper demonstrates that there is significant opportunity to improve the estimations of coal quality when using kriging with external drift. For example, the results show that when using the depth of a sample as an external drift variable there is a significant improvement in the accuracy of estimation for volatile matter. Furthermore, when using borehole wireline density logs as an auxiliary variable for ash content, there is improvement in the estimation of the in situ ash. The underpinning reasons for this are discussed in the context of the underlying geology and the physical properties of the coal. These findings hold promise for utilising cheaper proxies for coal quality parameters to dramatically improve data density and the quality of estimations.CITATION:Jeuken, R, Xu, C and Dowd, P, 2017. Improving coal quality estimations using geostatistics and auxiliary variables, in Proceedings Tenth International Mining Geology Conference 2017, pp 157–168 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By P Oikkonen

Sprayed concrete has played an integral role in underground rock support for nearly a century. However, concrete is also considered to be one of the biggest environmental problems in construction and mining, largely because of the high carbon footprint of cement and aggregates production. This is driving the industry to find ways to cut concrete usage where possible. Improving sustainability by cutting concrete material consumption also reduces application time and costs. Improving concrete properties can make it possible to design thinner linings, but as awareness of safety and longer design lifetimes are driving developments in the opposite direction, it is not realistic to see this as a major factor in cutting concrete consumption. More accessible solutions are focusing on layer thickness control and minimising rebound and wastage. Digital technology and innovation offer excellent tools for improving sustainability while optimising other aspects of the spraying process at the same time. A digital layer thickness control system gives near-real-time information to the sprayer operator with full coverage of the sprayed surface. This enables the operator to achieve consistent layer thickness on the first pass, in comparison to the traditional methods of overspraying with the aim of achieving sufficient layer thickness, probe drilling after the concrete has set, and respraying at a later stage if needed. Operator competence is the single biggest variable in a successful sprayed concrete process, affecting rebound and wastage levels. Unfortunately, the learning curve to become a master sprayer is quite steep and training on a real sprayer and real concrete requires a significant amount of time and money. Training in a virtual reality (VR) environment enables operator training to be carried out in a low-risk environment and provides a way of measuring performance and assessing and certifying the operators. After the VR training period, a novice nozzle operator has the basic understanding to start working on a real sprayer, and an experienced nozzle operator can benefit from the possibility of assessing their performance.

Mar 29, 2023

By J Bolen, I Cameron, M Huerta, M Okrutny, K O’Leary

As greater amounts of fine iron ore concentrates enter the marketplace, new investments in iron ore pelletising capacity are inevitable to deliver these concentrates to steel industry consumers. When investors assess the two well-proven pelletising technologies, the straight grate and grate-kiln, the most appropriate choice may not be immediately evident. Certain technical, market and site-specific factors will favour one technology over the other; investors need to be aware and understand these factors in order to make the best investment decision. Hatch has compared the merits of both technologies regarding plant configuration; type of iron ore processed; energy consumption and flexibility to use a variety of fuels; ability to produce the required pellet quality; required plant capacity and scale; operating and capital costs and environmental performance. A technology assessment checklist that investors should consider when making a new pellet plant investment decision is presented.CITATION:Huerta, M, Bolen, J, Okrutny, M, Cameron, I and O’Leary, K, 2015. Guidelines for selecting pellet plant technology, in Proceedings Iron Ore 2015, pp 45–52 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

Coal slurry pumping was introduced into the U.K. in 1973. Gateside packs were prepared in areas of containment using R.O.M. coal and a special fast setting cement. The packs restricted roadway convergence and moderated spontaneous combustion risks, but costs were high and alternptives were sought. A similar system using OPC and an accelerator had limited success. Much more successful was the Aquapack process which used dilute slurries of a special OPC based cement and an accelerator based on sodium carbonate and bentonite pumped simultaneously into la fabric packbag. The Tekpak system using HAC and a much modified calcium sulphate mixture superceded Aquapack on the grounds of improved cement pumping life lower alkalinity and lower costs. A further modification of this system gave a cement with a 24 hour pumping life thus obviating flushing out pipe ranges except at the week-ends, improved packbags also increased the efficiency of the process. The hazard of spontaneous combustion can be inhibited if air supply channels across the waste can be located and plugged. Using gas samples from pack pipes to locate the heating and injecting a special grout, formulated from bentonite, sodium silicate and thixotroping agents. into the waste on the intake road has proved a successful method of controlling heatings. Mine' roadway and face cavities are being safely and successfully filled with cementitious foams produced in a novel placer machine. The foams are based on fast setting cements with specialised foaming agents. Up to 13 cu. metres per hour of fast setting thixotropic foams can be produced and their use is now widespread throughout U.K. coal mines.

Jan 1, 1986