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By Channon W, Dube M, Makwana M, Kerfoot D. G

In early-1995, the Bindura Nickel Corporation commissioned a pressure leach plant at its Smelter and Refinery complex located in Bindura, Zimbabwe. The novel pressure leach process was developed by Sherritt to treat the nickel-copper sulphide residue produced from the original atmospheric leach circuit. The process extracts essentially all the nickel from the nickel-copper sulphide residue under non-oxidising acid pressure leach conditions, thereby producing an upgraded copper sulphide residue suitable for smelting and refining to electrolytic copper. The commissioning of the pressure leach plant was relatively smooth and design conditions were achieved within six weeks of operation. This paper presents a brief description of the process development and the plant design, followed by highlights of the plant start-up activities and summary of the plant performance.

Jan 1, 1996

By Weining L

In-situ experiments were performed in a tunnel built in loess soil with the displace- ment components of the tunnel lining and the acceleration components of the tracks measured during the passing of trains. The measured parameters were then studied by the spectral method. As a result, the dynamic forces of trains was simulated numerically and a deter- ministic dynamic nonlinear analysis was carried out by means of finite element method. The results obtained by two different approaches were in fair coincidence. Results of the study indicate, that the low and medium frequency components of the dynamic train loading would be crucial for the dynamic responses of the tunnel lining and surrounding mass, and their effects would increase with the speed of passing trains within a certain range.

Jan 1, 1987

The excessively high cost of production in underground coal mines has made the survival of many coal mines around the globe economically non-viable. The global competitive coal market speaks itself of the desirability of a lower operating cost in conjunction with a higher productivity performance, particularly in underground coal mines, and calls for an optimal production planning under a host of constraints. Such a task of optimal planning is not an easy exercise like that of traditional planning based merely on intuition, experience and subjective judgement. It essentially demands a thorough understanding of the complex interaction of mine sub-systems for judicious application of optimisation tools and techniques available with operations research. A few large mines around the globe have made an effective use of a sizeable number of operations research packaged programs for optimal decision-making (Grayson, 1989). The success of practical applications of operations research techniques made in a variety of mining problems in large mines in different parts of the world will hopefully make inroads to smaller mines in years to come. The present paper is an addition in the series of such applications of operations research tools to mining problems, particularly with reference to an underground coal mine in India. The paper is based on research work (Jawed, 1990) and deals with the development and use of a mathematical model for production planning in underground coal mines under multiple objective environment subject to a host of constraints.

Jan 1, 1995

By D Jones

The development, piloting and engineering design of an innovative water treatment system for process water produced by a uranium mine mill are described. The process incorporates lime/carbonate softening (Stage 1), reverse osmosis (Stage 2) and biopolishing (Stage 3) to produce water of quality suitable for release to the receiving environment. Comprehensive performance data are presented for each stage. The unique features of the proposed process are: recycle of the lime/CO2 softening sludge to the uranium mill as a neutralant; potential use of power station off-gas for carbonation; and the potential recovery and recycle of ammonia from the RO reject stream.

Jan 1, 2003

By W J. Bruckard

In Australia, ilmenite is produced from beach sand deposits. These deposits contain varying quantities of the valuable minerals zircon, rutile and ilmenite, along with a variety of other minerals. The valuable minerals are upgraded using combinations of gravity, magnetic and electrostatic processing techniques to yield high-grade products. One of the penalty elements present in ilmenite concentrates is chromium, present mostly as chrome spinels. This mineral is particularly difficult to separate from ilmenite, as the properties of the two minerals are very similar in relation to the traditional separation processes. While the deposits which have been treated in Australia in the past have had only low levels of chromium present, many of the newer deposits contain much higher levels of contamination and, thus, there is an increasing need to develop robust processes to separate chrome spinel from the ilmenite. Flotation, which is a unit process with the potential to solve this problem, has surprisingly received little attention for this application. The literature suggests the research effort to characterise the general flotation properties of chromite (chrome spinel with high chromium content) has been extensive and a substantial amount of data is available. However, the problem of separating a small amount of chrome spinel from a large amount of ilmenite requires a different approach to that from separating chromite from siliceous gangue, which has been the main commercial focus of chromite flotation in the past. Much of the work done has been fundamental in nature and the results obtained are fairly inconsistent, as is the testwork completed at batch and pilot plant scale. While these inconsistencies have been attributed to the variable composition of the mineral, there is little evidence supporting this premise. Just as chrome spinel and ilmenite have similar physical characteristics, the flotation response of both minerals is also similar. This paper reviews the literature relating to the flotation of chrome spinel and presents a considered approach to the development of a robust flotation method to separate chrome spinel from ilmenite.

Jan 1, 2001

By M G. Aylmore

Thiosulphate is an attractive alternative reagent to cyanide for processing gold ores. It is relatively cheap and non-toxic, forms relatively strong gold and silver complexes, and readily leaches gold ores in ammoniacal solutions, catalysed by Cu(II). It is particularly suited to carbonaceous ores where the recovery of gold by cyanide is poor. However research over the past 20 years has identified a number of issues and impediments that must be understood or overcome before an overall process can be demonstrated as practical and economic for typical oxidised gold ores. This paper reviews our current understanding of thiosulphate chemistry and mechanism of gold dissolution, and discusses the stability of thiosulphate and polythionates. It then reviews the results of leaching various gold ores that have been reported in the literature, discusses gold recovery options, and considers environmental and toxicity issues. Some of the issues that require further research include decreasing the oxidation of thiosulphate by Cu(II) or other oxidants, increasing the extraction of gold compared to cyanide, and understanding the variation in gold recovery between ores. More work is also required to minimise the effect of polythionates on gold recovery using resins or alternative absorbents, to improve the elution of copper and gold from resins, and to recycle or minimise the concentration of reagents.

Jan 1, 2002

The application of modern sciences prior to nineteenseventies have resulted in the placing of Continental Drift theory into broader concept of Plate Tectonics. The concept is applied to explain the Cenozoic Tectonics of North Sumatera.Oceanic crust flooring the Indian Ocean is moving northeasterly and being obliquely subducted at a Benioff zone along the western margin of Asian Plate, marked by the Sunda Trench in the west coast of Sumatera. This phenomenon was generated since late Mesozoic, continued during Cenozoic era up to present day, resulted an exellent example of arc-trench system which can be traced along SW - NE transect of North Sumatera.The oblique-subducting plate of Indian Ocean beneath Asian Plate, together with spreading of Andaman seafloor beginning in Pliocen epoch, have led to the origin of Sumateran Fault System; the System extends throughout the length of Sumatera island. In the region under review it comprises almost contiguous set of broadly SE-trending. Evidences for transcurent-dextral displacement have been observed.

Jan 1, 1990

The low grade Mount Charlotte orebody was first mined with minimum capital expenditure by mechanised cut and fill stoping. The lower block was prepared simultaneously for open stoping by shaft sinking and installing another crusher and services. Similar development for the third block was discouraged by economic factors and reduced tonnage. Decline develop- ment required less capital and opened up ore reserves commensurate with advance, providing flexibility to stop operations without commit- ment: A 1 in 7 decline measuring 4.25m x 5.5m to accommodate standard Euclid 25 tonne dump trucks was developed south of the orebody. A fleet of four trucks average 12 loads each per shift over a haul distance of 700m.

Jan 1, 1973

Results of blasting trials conducted at Gregory Mine, a large open cut coal mine situated in the Bowen Basin, show that fragmentation was improved or equalled whilst reducing the amount of explosives previously required. This was achieved by a system of deck loading whereby two or more explosive charges, separated by air gaps, were positioned in the blast hole, thereby extending the effective explosive column whilst minimizing the total explosives required. In the three trials to date, a saving of approximately 213 kg of ANFO per blast hole was achieved. This represented an approximate 20% reduc- tion in ANFO requirements.

Jan 1, 1989

By B J. van Loggerenberg

The capital cost of major items of mining equipment is very high. The operating cost of such equipment is also high. It is therefore important that such expensive equipment is used productively. To this end mine management uses production data systems and management accounting systems to monitor events and provide data for analysis to enable management to make operating and business optimisation decisions. This could be done better if there was an understanding of productivity in terms of its utilisation and efficiency components. What has been missing has been a methodology to properly account for the productivity of equipment in terms of its contribution in dollars to the costs and profit of the mine. An explanation of the Productivity Accounting methodology will be given. It will then be shown that productivity has two components, that of capacity utilisation and efficiency. These are defined and the dollar contribution of each to costs and profit shown. The efficiency component tracks the effect of proportional changes in input cost quantities used in the mining process as mining production changes. The capacity utilisation component tracks the effect of step changes in the input cost quantities used in the mining process as mining production changes.

Jan 1, 2003

By A M. Myrvang, B Nøst, N Q. Trinh, I S. B Bergh

The iron ore producer Rana Gruber AS is situated in northern Norway just below the Arctic Circle, and has been producing hematite and magnetite concentrates for more than 60 years. Since the late 1990s, the major part of the production comes from a sublevel stoping underground operation after many years of open pit mining. Despite moderate mining depth, the operations have experienced considerable rock stress problems due to quite high tectonic, horizontal stresses. To manage the problems, comprehensive rock mechanics investigations have been carried out by SINTEF, a major contract research organisation. This has included in situ rock stress measurements, laboratory investigations and numerical modelling. Based on this and practical experience, satisfactory design of vertical and horizontal pillars was achieved. At depth, the ore width increases from 30–40?m to more than 100?m. This, together with a major planned increase in production, called for a change of the mining method. After thorough investigations and considerations, it was decided to change to sublevel caving, very much like the LKAB system. The development of the new system has been closely followed up by rock mechanics measures, including 3D numerical modelling and comprehensive monitoring of deformations and rock stress changes. To achieve a satisfactory caving of the hanging wall, all vertical and horizontal pillars in the sublevel stoping area had to be removed. This has been a challenging task, and the development of the caving has been slow until recently. However, now the caving develops satisfactorily.CITATION:Bergh, I S B, Trinh, N Q, Myrvang, A M and Nøst, B, 2014. From sublevel stoping to sublevel caving at Rana Gruber, Norway – rock mechanical aspects, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 323–330 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By D Jordan, R Wilmoth, J LeFever

Exposed, open pit mine highwalls contribute significantly to the production of acid mine drainage (AMD) thus causing environmental concerns upon closure of an operating mine. Four innovative technologies were evaluated under the US Environmental Protection AgencyÆs, Mine Waste Technology (MWTP), Prevention of AMD Generation from Open Pit Highwalls Demonstration Project. This project is funded by the US Environmental Protection Agency (EPA) and jointly administered by the EPA and the US Department of Energy (DOE) through an Interagency Agreement. The objective of the field demonstration was to evaluate the technologies ability to decrease or eliminate acid generation from treated areas of the highwall in comparison an untreated highwall area. The field demonstration was performed at the Golden Sunlight Mine (GSM) a subsidiary of Placer Dome US, located near Whitehall, Montana. GSM is an operating gold mine. The highwall at GSM was divided into five plots measuring 15.24 by 15.24 m and each technology was assigned a plot with the fifth plot being used for comparison as a background control plot. The four technologies were spray-applied. The applied in situ treatment technologies included: a modified, furfuryl alcohol resin sealant, utilising wood and agricultural by-products to coat the rock surface; EcobondTM ARD, a phosphate based process that forms a stable, insoluble compound, coating the rock surface; and two AMD passivation technologies, magnesium oxide and the Dupont technology developed to create an inert layer/coating on the pyrite, preventing oxidation. The technologies were evaluated using the following methods: ASTM D 5744-96, accelerated weathering of solid materials using a modified humidity cells; mine wall residual wall rinse sampling; microscopy; and core drilling followed by water injection testing. The following paper describes the technologies used for passivation of acid generation from the highwall, the field demonstration, and the testing results from the background and each technology plot.

Jan 1, 2003

By Tran T, Young D

During the processing of gold, effluents that are discharged into the tailing dams contain free cyanide, metal cyanide complexes of zinc, copper, iron, etc and their oxidised products such as ammonia, cyanate and thiocyanate. A knowledge of how different cyanides behave in the solution is vital to metallurgists working in the area of cyanide waste treatment. Although the free cyanide ion is not stable in aqueous solutions and is expected to degrade in a natural environment by atmospheric oxidation, the metal cyanide complexes, especially of iron, are very stable. The CHEMIX program from the THERMODATA package, developed by the CSIRO Division of Mineral Products, was used to evaluate various copper-cyanide and iron-cyanide systems. The simulation of these systems show how the free cyanide and cyanide complexes behave at different conditions of solution composition and acidity (pH).

Jan 1, 1991

By B Murphy, T Mattsson, R Crosbie, T Maksimainen

"An Outotec e500 TankCell, with 500 m³ of actual flotation volume, was commissioned at the Kevitsa Cu-Ni-PGE concentrator in northern Finland during 2014. This flotation cell was implemented at the head of the existing copper circuit as the first Cu rougher flotation cell. This was the first flotation cell of this size to be run under production conditions by any supplier anywhere in the world.The cell has been in continuous operation since start-up in October 2014 and has provided improvements in metallurgical performance at very low specific power consumption. On average, the cell has recovered 71 per cent of copper contained in the 0.37 per cent Cu flotation feed at a concentrate grade of 17 per cent Cu. The specific power consumption for the cell (excluding blower power) is typically around 0.4 kW/m³.After start-up, the impeller speed and superficial gas velocity were varied and the impact on metallurgical performance measured. In this paper a review of the cell operation at Kevitsa is given. Furthermore, the impact of mixing and gas dispersion on metallurgical performance is presented.Citation:Crosbie, R, Mattsson, T, Murphy, B and Maksimainen, T, 2016. Metallurgical Performance of Outotec's e500 TankCell at the Kevitsa Cu-Ni-PGE Concentrator, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 127–134 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By A Innis, A Bye, B McCarthy, S Glover

Technology adoption in the mining industry has been steadily increasing over the past decade, driven by the need to improve operational efficiency, safety, sustainability, and profitability. As mining companies wish to implement solutions to improve mining safety and productivity, various technologies are being integrated into mining operations to enhance processes, reduce risks, and optimise resource utilisation. Adoption of new technologies such as autonomous trucks requires a strong focus on foundational operational technology (OT) and a systems-thinking approach. OT support is critical however, OT is traditionally not considered or integrated into standard maintenance activities. Consequently, sourcing and applying service support to OT systems in real-time has posed significant challenges to date. Neglecting the monitoring and upkeep of these operational technologies and equipment can lead to a host of adverse consequences. Operating instability becomes more prevalent, necessitating reactive measures, and the vulnerability to cybersecurity threats increases significantly. To address OT monitoring and maintenance challenges, a systems wide mindset and remote support discipline must be utilised. Remote operations support refers to real-time, 24/7 monitoring, control and support of site OT: network, production systems, maintenance systems, enterprise systems and mobile and fixed plant through a single interface remote from site. The presence of a disciplined team, grounded in a systems-oriented approach, is of the utmost importance to remote monitoring, given the intricate interdependencies of OT systems. The ability to understand the relationships among multiple systems, coupled with the capacity to distinguish between symptoms and root causes, assumes a pivotal role in operations. Through diligent monitoring and the astute understanding of system thresholds, remote operations support can actively identify and alleviate constraints, in turn, serving as the enabler for transformative advancements in technology output.

Sep 1, 2024

Inadequate understanding and/or assessment of technical and economic risk associated with geological uncertainty are key reasons many mining projects do not achieve forecast profitability. In the last 20 years many new and existing mines have experienced geology related problems, including lower than planned development and production rates, geotechnical/stability issues, unplanned dilution, ore loss, reduced metallurgical performance, environmental management concerns and unbudgeted capital/operating costs. Greater emphasis on the evaluation and communication of uncertainty associated with geological interpretations for feasibility and operations management results in better decision-making. The outcome of better decision-making is more efficient mining yielding enhanced financial returns for the mining industry.

Jan 1, 2009

The twin iron ore islands of Cockatoo and Koolan are located in the spectacular setting of Buccaneer Archipelago off the Kimberley coastline of WA.Cessation of ore shipments from Koolan in 1993 ended 42 years of continuous mining activity which began with the first shipment of ore from Cockatoo in 1951.

Jan 1, 1993

The mining of Australia's rich and diverse mineral resources has been central to the development of the continent by "Europeans" over the past two hundred years. Mining has historically been encouraged (to varying degrees) by development-orientated state governments (the. managers of largely Crown-owned resources) and since Federation, by successive Com- monwealth governments (which have seen mineral development as a means of generating export revenue to fund predominantly social-welfare orien- tated budgets). This marriage of convenience between governments and the mining industry has to date served all parties well. However, Australia's entry to a new world economic environment at a time that community percep- tions are changing (owing to an education-inspired challenge to "old" values) is challenging the hitherto held assumption that mining develop- ment is always aligned with the well-being of the State and community. Issues such as the type and extent of State/Commonwealth government taxation, resource ownership and control, the environment, land use con- flict, the extent and desirability of secondary processing and infrastruc- ture funding are being debated in the public arena. Opponents of mining in the community are well-organised and are well funded, articulate and more importantly, they have effective communication channels with most governments, irrespective of political complexion. Apart from some television-orientated corporate image building and recent efforts by AMIC, the industry's response to this challenge has been unco-ordinated, poorly directed and arguably ineffective. Professionals working in the industry are concerned about the community's perception of themselves and their industry. Recognizing that the Australian democratic system ensures that, in the large, government at its various levels, is reflective of and responsive to the views and aspirations of people, the industry's response must be wide- ranging, equally articulate and couched in a form which is politically acceptable. New objectives in providing information to the public and its educators must be formulated. Moreover, professionals are looking for new directions from industry leaders. The Institute is well placed to facilitate this process.

Jan 1, 1988

The Project Financing Industry is currently being expanded en- compassing greater competition due to the improved worldwide economy. This has meant that money is in greater supply than demand for both loan and equity investment and is available for larger and higher risk ventures. The consequence of this is that the Project Financing Industry should be better able to provide more innovative forms of financing to meet the needs of mining and petroleum companies, regardless of size. Large mining and petroleum companies in Papua New Guinea should therefore be looking for ways to raise equity funds for exploration in greenfield areas, diversifying their risks through acquisition, and seeking to reduce their costs of borrowings. The small to medium sized mining sector should be looking to raise equity for increased ex- ploration on tenements and, where possible, to raise borrowings to fund expansion and further development of their projects. In summary, it is a period during which companies should take ad- vantage of available funding to augment their strategic plans and increase their long term returns to shareholders.

Jan 1, 1997

By R L. Koenig

Previous papers at Metplant conferences have covered the options for crushing and grinding circuit selection. High Pressure Grinding Rolls (HPGR) may have considerable advantages over autogenous milling circuits but test work and evaluating different grinding circuits must be done to establish which circuit provides the best option. The Hawsons low grade magnetite project provides a specific example in using thorough test work, careful simulations and detail in design to allow the evaluation of grinding circuit performance. Fortunately tools are available for this evaluation and the test work for the Hawsons iron ore is detailed in this paper. The results of the test work and simulation indicates that although the Hawsons iron ore is competent in terms of autogenous milling given the medium hardness of the ore in the Drop Tests, the HPGR testing indicates that the use of HPGR is likely to use half the energy requirement. This is a characteristic of the Hawsons iron ore and is likely to be valid for other iron ores in the Braemer Iron Formation which stretches from the Hawsons lease in New South Wales to Razor Back and South Dam in South Australia. The Hawsons magnetite iron ore resource has been known from the early 1960s when CRA explored the area. However, the Pilbara region was discovered in this era and this led to development of high grade direct shipping grade hematite ores. Carpentaria Exploration (Capex) rediscovered the magnetite whilst undertaking multi-commodity exploration in the Broken Hill district during 2009. The magnetite grade was found to be low at around 16% Davis Tube mass recovery (DTR) but despite this, the project provides a positive business case as a result of the following key factors:• The mineralisation is particularly soft for crushing and grinding with a Bond Work Index of 6.3.• The mineralised rock fractures easily preferentially along grain boundaries.• The location is close to mining infrastructure and a skilled workforce in Broken Hill, 60km to the North East.• It is close to road and rail infrastructure for access to the resource.• The only contaminant in concentrate is silica.• The resource contains many billions of tonnes of magnetite mineralisation.The low Bond Work index is a key characteristic of the Hawsons iron ore and the use of autogenous milling and HPGR circuits is compared to other iron ores indicating why the plant energy requirement may be just as important as iron ore grades.

Aug 8, 2011