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By B C. Povey

HPGR technology has been used at a number of magnetite mines in the world and have significant energy advantages over SAG and AG technologies. The early design at Los Colorados in Chile has been in operation for more than 12 years - and operates very successfully though only reduces the feed size to -5mmThe Whyalla project magnet design pushed the concept to produce a preconcentrate of 80%-350micron - a significant reduction on previous plants though with some wear problems in the early years. The Karara design backpedalled slightly and will only crush to 80%-1.8mm.However, the design issues of using a HPGR to further reduce the feed size continue to be explored. The aim is to reduce the process risks associated with wear and also to reduce the complexity of the downstream process - with consequent benefits in terms of capital and operating costs.The designs are being developed for a couple of projects - one planned to produce 20Mtpa of concentrate with the potential to not only remove SAG and AG milling but also ball milling. The concept is to use multiple passing through the HPGR since, on the data available, the efficiency of the HPGR to reduce size does not significantly diminish as the feed size is reduce. This can be have benefits in both capital and operating cost.CITATION:Povey, B C, 2013. Pushing the use of high pressure grinding rolls in magnetite circuits, in Proceedings MetPlant 2013 , pp 176-189 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

By Brien RT, O&apos

The work reported in this paper extends,-bhsb on the "Heat Hardening of Artificial Magnetite ;Pellets"., which was described at the- International Symposium on Agglomeration ;-sponsored by the American Institute. of Mining, Metallurgical and Petroleum Engineers at Philadelphia; U.S.A. in April, 1961. Whereas- that work was of a.,more basic nature, -serving to illustrate the suitability of artificialòmagnetites with various.admixtures, to the application of heat hardened pellets, on: this occasion the aim-is to illustrate the procedures-which were used-to- establish the dimensions of commercialòrecuperativ strands for Australian raw materials,The nature of the pellet feed, i.e. relatively uniform :spheres of4 3/8 in. - 7/16. in. diameter, makes it possible to use small scale static pots for test work. By the use of a closed system and the measurement of suctions, gas f lows, and temperatures through beds, the speed and heat requirements of the various stages of heat hardening can be measured, so: that for a specified quality of product estimates can be made of the broad design characteristics of a moving grate system. In practice of course it is .usual to correlate the data from this type-of :experimental 'apparatus with . existing production units upon which good operating data, in the statistical sense, are available.

Jan 1, 1963

There are many factors influencing the way in which a mining company disposes of tailings. Some of the more important factors include physical and chemical properties of tailings, cost, availability of dam wall construction materials, type of mining operation, topography and environmental constraints. As a result, the mining industry has seen a diverse and innovative range of disposal methods developed to satisfy the many conditions imposed at tailings disposal sites. This paper discusses a range of tailings disposal methods currently practiced in the mining industries in North America. These methods include various inpit disposal techniques, upstream, downstream and centreline dam construction and zoned earthfill or rockfill embankment construction. The thickened tailings disposal method and the disposal of fine clays are discussed. The importance of improving the depositional properties of tailings to enhance storage capacity, water reclaim, dam wall stability and final reclamation is stressed. It is important that mining companies are made aware of the full range of disposal methods and dam construction techniques available today. Such an awareness will help improve the planning, design and construction of safer and more efficient tailings disposal facilities in the future.

Jan 1, 1989

By Woodcock J. T, Rummel P. H, Sparrow G. J, MacRae C. M

An automated method, which is believed to be the fastest in the world and which can be used by mineralogically-untrained technical assistants, has been developed for the rapid location of native gold particles and other gold minerals down to 1 pm in size in ores, concentrates, and tailings using a scanning electron microscope. Searching of a 25 mm diameter polished block in 1 pm steps usually requires 3-4 h. Examples of the location of native gold and gold tellurides in drill core sections, in crushed ore samples and gravity and flotation concentrates, and in various metallurgical test products are given. The results have application in ore exploration, in guiding metallurgical test programmes, and in assessing metallurgical per- formance in testwork and in operating plants.

Jan 1, 1991

By Scherbatsky VB, zon BM, Babushkin NM, Kitaev BI, Shabel&apos

The structure and hydrodynamics of the raceway zone of a blast furnace was studied on a cold model representing a sector containing two tuyeres. The model differed from the usual in that it was prov- ided with continuous flow of the coke layer at pre- determined rates, had provision for changing the tuyere parameters (diameter, protrusion, inclinat- ion) and irrigation of the layer with liquid. A combination probe was developed which per- mitted simultaneous measurement of the pressure field both across the area and through the height of the layer as well as determining the topography of the raceway. The velocity fields in the layer were measured with a specially made impulse thermo- anemometer. The determining criteria of the model were taken as the relationships between the energy of the blast and the particles, the dimensions of the raceway and the cross-section of the tuyere. The model established the effects of the tuy- ere structural parameters, blast parameters and amount of liquid products of smelting on the con- figuration of the raceway, the structure of the layer, pressure and velocity fields in the vicinity of the tuyeres and in the vertical direction through the layer. The properties of the raceway formation and the structure of the layer in motion have been clarified.

Jan 1, 1981

The results of laboratory grindability tests on coal are of primary importance to the designers and operators of coal grinding mills, and coal handling plants in general. However, the potential industrial application of these test results have not been fully realised due to a lack of laboratory-test/field data correlations. This paper focuses on the grindability characteristics of Queensland coals, and provides a new look at an old problem in terms of (i) a more rigorous characterisation of the grindability properties of coal and its associated mineral impurities, and (ii) the correlation of laboratory grindability test results with the size characteristics of run-of-plant thermal coals, and their pulverising characteristics in full-scale mills. A new grindability test is also proposed based on the Yancey, Geer and Price laboratory abrasion-test mill.

Jan 1, 1991

Traditionally, the Lead Lode at Broken Hill has been represented on presentation plans, cross sections and diagrams in scientific papers as a solid black mass, around which the more 'interesting' and 'structurally useful', wall rocks appear to wrap. Structural analysis of the Broken Hill orebodies has usually turned to these wall rocks to determine the structural history of the mineralisation.This tendency to represent the orebody as a massive single entity is incorrect and the aim of this paper is to illustrate that sulphide orebodies (in this case Lead Lode), are a dynamic part of the mine stratigraphy. They can preserve a great deal of useful structural information that can be recorded with detailed internal mapping.Three main categories of ore type are recognised in Lead Lode; Stratiform ores, Mobilised ores and Metasomatically altered ore. The ore types in these categories occupy or have formed in distinct structural and stratigraphic positions and have clearly recognisable inter-relationships.

Jan 1, 1993

By Denby B

The ever increasing demand on land use has led to large areas of land being considered for development, which because of past mining activities are covered by substantial depths of fill materials. This paper examines the problem faced with the development of land infilled with open cast mining backfill, in predicting the behaviour of the fill upon development. To be able to design foundations suitable to withstand the movements that occur within open cast backfills or design a backfilling operation that produces land suitable for a proposed after development, a means of predicting backfill settlement is required. Factors critical to this prediction are the timing of backfilling operations, the compactive state of the backfill and the inundation of the backfill. The analysis of a considerable quantity of data collected from the monitoring of backfilling operations and backfill movement at a range of open cast coal sites located within the UK has given the authors a better understanding of how open cast backfills behave in terms of long-term creep settlement, collapse settlement and how these are effected by backfill scheduling. This knowledge has been encoded into a program running under Microsoft Windows that enables a user to make settlement predictions for a point, a given section or area or for the whole site. Differential settlements, critical to any development design, can also be determined between any two points taking into consideration the heterogeneous nature of open cast backfills. The program was tested with data from an open cast coal site in the UK. Compaction monitoring during the placement of the backfill material enabled a model of the backfill to be constructed taking into account backfill properties and scheduling. This model, taken as input into the program, enabled future backfill settlement predictions to be made. A comparison is given between these results and actual settlements obtained from a short-term settlement monitoring scheme.

Jan 1, 1995

The New Guinea Mobile Belt is the northern zone of the Melanesian Orogeny (Dow and Sukamto, 1984), which consists of a complex zone ofupthrusted and accreted, regionally metamorphosed geosynclinal sediments and volcanics of Mesozoic to Eocene age and the overlying sediments. On the northern margin of this accreted terrane, formed an Eocene to Middle Miocene island arc. The North New Guinea Basin formed during the Upper Oligocene on the accreted margin. The depositional history of this basin is complicated by major crustal movements during the Upper Miocene to Holocene. During the Middle to Upper Miocene two magmatic arcs were emplaced. The northern magmatic arc is in part, spatically and genetically related to the Eocene to Middle Miocene island arc. The Maramuni-Utawa Magmatic Arc (southern) is a result of the Oligocene accretion and regional metamorphism. Coincident witt these magmatic arcs are belts of mineralization containing porphyry Cu-Au, epithermal/hydrothermal Au, Ag + Cu-Pb-Zn, exhalative Cu-Pb-Zn + Ag-Au, lateritic Ni-Cr-Co + PGE and alluvial Au, PGE, Cr occurrences and deposits. An intergrated tectonic model is presented for these and other data for the northern zone of the Melanesian Orogeny.

Jan 1, 1990

By Raudsepp R

Since 1991, the Porgera Joint Venture has processed refractory sulphide flotation concentrate by pressure oxidation with the subsequent gold recovery, from the washed residue, via a conventional leach/carbon-in- pulp (CIP) circuit. The capacity

Jan 1, 1997

By Aspinall T. O, Bell L. C

Increased awareness and stricter enforcement of regulatory requirements for adequate rehabilitation of surface mining sites has made environmental planning an essential part of strip mine planning. Rehabilitation is site specific and should be based on data which relate to that site. Cost-effective spoil pile design to minimise erosion is an important part of rehabilitation. Spoil pile design is an integral part of strip mine design. QCT Resources Limited has provided a postgraduate scholarship toward research in this area. The controlling factors of spoil pile design are post-mining land use, drainage requirements and degree and rate of erosion. The extent to which mine design is controlled by these factors is determined by regulatory requirements. To plan acceptable rehabilitation programs, erosion processes must be accurately modelled, and a range of erosion prediction models are available. Useful prediction models can be placed in two categories with the first category containing soil loss prediction models which can be used to predict the amount of soil lost from an area over a short or long term basis. Models in this category include the Universal Soil Loss Equation (USLE), Water Erosion Prediction Project (WEPP), Griffith University Erosion and Sedimentation System (GUESS) and Chemical, Runoff and Erosion from Agricultural Management Systems (CREAMS). The second category contains topographic evolution models which give an indication of the long term morphological development of a formed surface subjected to erosion processes. Models in this category include "Topog", Willgoose's Physically Based Catchment Evolution Model and Areal Nonpoint Source Watershed Environment Response Simulation (ANSWERS). The USLE has been used in the agricultural field for soil loss prediction. To apply the equation to mine sites in Central Queensland, it is necessary to understand the factors affecting erosion at the sites. This understanding should allow the variables of the equation to be quantified. The rainfall factor applied in the USLE is independent of engineering design or soil management techniques. The factor of spoil erodibility is dependent on the material's physical and chemical properties and can vary from site to site. In the equation, the topographic factor, cover and management factor and conservation practices factor can be varied by design to reduce erosion on rehabilitated areas.

Jan 1, 1991

By Large RR

Underlying the 15 million tonne, high grade Hellyer volcanogenic massive sulphide deposit of western Tasmania is an extensive, well developed, and well preserved stringer system. Pervasive alteration of the footwall mafic volcanics occurred as the hydrothermal system initiated. Mineralogical zoning exists within the footwall alteration pipe, with a central siliceous core giving way to zones of chlorite, chlorite-carbonate, sericite-chlorite, and finally sericite-quartz on the margins (stringer envelope zone). However, the alteration morphology and zonation is not symmetrical around the central siliceous core; eastward the alteration zones are steeply dipping and terminate abruptly under the massive sulphide, while westward they extend out under the ore body in a blanket fashion. Geologic evidence indicates that the pervasive alteration started with the development of sericite-quartz which was subsequently overprinted by chlorite and finally quartz-sericite as the hydrothermal system became focused towards the centre of the stringer system.

Jan 1, 1990

The large, high grade 3000 and 3500 copper orebodies at Mount Isa lie greater than 1200 m below the surface, and partly beneath the silver-lead-zinc mining operations at the Isa Mine.Since discovery over 30 years ago, the primary data acquisition programs have been integrated with long-term copper production strategies. These potentially sizeable and distinctly separate accumulations of copper mineralisation are the only sources capable of supplementing a decline in output from the 1100 orebody in the 1990s. Within a decade these deeper copper orebodies will become the major source of copper ore.

Jan 1, 1993

By A Boeing

Rock-breaker automation and remote operation improves the safety and efficiency of mining operations. This paper presents an overview of the Rocklogic rock-breaker automation system architecture that provides collision avoidance, automated parking and remote operation functionality. The system consists of a distributed computer control system that interfaces with sensors attached to the rock-breaker, the rock-breaker hydraulics and the site infrastructure. We present results of an automated Transmin rock-breaker installed in a production environment at an underground Australian mine site. The system has been in production use for over 900 days, during which there have been no reported collisions and 100 per cent adoption of the remote operation technology. As a result, Rocklogic has significantly improved the safety of rock-breaking operations and reduced the rock-breaking cycle time, thereby improving the site’s overall throughput.CITATION:Boeing, A and Douglas, E, 2014. A remotely operated robotic rock-breaker with collision avoidance for the mining industry, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 131–136 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

By Sutherland R. A, Rawling K. R

The Nanisivik Mine is located 750 km north of the Arctic Circle at the north end of Baffin Island in the Canadian High Arctic, and has been in production since 1976. The paper describes the regional and local geology and the current mining and mineral processing operations, including recent innovations in each area. The Nanisivik zinc-lead deposits comprise Mississippi Valley type sulphides in a block-faulted sediment sequence of Proterozoic age. The deposits formed in two mineralizing stages by replacement of the carbonate host rock. Exploration techniques adapted to the permafrost environment include high frequency EM and ground probing radar. Core drilling is done with calcium chloride brine but trials with heated flushing water indicate potential for cost reduction. The predominant mining method at Nanisivik is room and pillar. Cut and fill is used in some satellites to the main zone. Due to the permafrost, dry drilling is employed in the underground mining. The permafrost enhances ground stability, permitting large underground openings and, as a result, the use of relatively large scale mining equipment. For power conservation, a remote control system for the ventilation fans has reduced mine power costs. The milling of the simple coarse-grained ore in an arctic environment requires special techniques in the design and operation of the plant for materials handling, utilisation of waste heat, reagent selection and tailings disposal. Regulated heavy metal contents in effluents discharged to the sensitive environment are achieved by natural processes. A recent change from sub-aqueous disposal of tailings to beach type deposition within a cell in the tailings area is reviewed. Planning closure of the property presents special problems and an opportunity for innovative techniques. Approximately 25 per cent of the employees at Nanisivik are drawn from the Inuit population of the Canadian Arctic. As the first permanent industrial activity in the High Arctic some innovative approaches to employee relations were required which have resulted in a very stable, culturally mixed community in a remote location.

Jan 1, 1993

The Iron Prince orebody occurs within the Lower Middleback Jaspilite Horizon of the Middleback Group and consists of hematite within host rocks of jaspilites and schists. The ore was probably the product of leaching of silica from jaspilites and replacement by iron, concentrations occurring in suitable structural traps. The narrowness and the presence of extensive dolerite amphibolite dykes within the orebody make it essential to operate a grade control programme in advance of the faces. Information from drilling is drawn up on bench plans, step plans and impurity overlays, and these serve both in day to day production planning and in long term planning. Mining is done selectively by open-pit methods and blending conducted by keeping at least three faces of different grades of ore open at any one time. No stock piles of ore are kept for blending, but contact ore, contaminated ore and enriched material are dumped for later beneficiation.

Jan 1, 1971

By Ruston R

When coal mining first commenced in Australia, the principle objective was low cost production with development directed toward recovery of 'easy' coal. Future expans- ion of these early mines into major under- ground operations was neither envisaged nor planned. As the demand for coal grew, these mines were expanded to increase output. however, the absence of initial ventilation planning brought about ad hoc systems wh;ch required continual repair and upgrading. These systems proved satisfactory in the short term because the majority of undergrouni coal mining operations were carried out at relatively shallow depths where gas emission rates were low. By comparison, coal is now being won at depths exceeding 500 metres with a corresponding increase in gas flow from the working seams and adjacent strata. The following paper addresses, firstly, the planning and institution of a ventilation system in a mine where previous inefficiencies were many, and secondly, the value of pre- planning a mine ventilation system in the early stages of mine development, and the need to continually review and upgrade the plan to account for unforeseen ^hanges.

Jan 1, 1983

By Dennis B

The Hilton Mine, 20 km north of Mount Isa was discovered in 1947. The underground mine has been a significant producer from 1989. The long development history is the result of complex orebody geometry, difficult metallurgy, dewatering problems and competition for development funds from the then expanding Isa Mine at Mount Isa. At present it produces 1.4 million tonnes annually. Its 21 million tonnes of reserves are necessary to supplement Isa Mine production.Hilton Mine is located in the Urquhart Shale formation of the Mount Isa Group, within the Mid Proterozoic Mount Isa Inlier. The seven developed orebodies have suffered strong structural deformation. Each orebody has a unique mixture of mineralogy and texture which effects ore value and metallurgical performance. These characteristics have proven useful for correlation purposes.The faulting and folding have caused difficulties with orebody interpretation, geomechanical complexities and has influenced the choice of mining methods: Initial cut and fill and open scope designs have given way to bench mining methods in response to better understanding of the eedloav and economic constraints.

Jan 1, 1993

Mount Isa Mines' Hilton Mine was brought into large-scale production in 1990/91 at a time of sharply falling metal prices. To ensure the operation's survival and eventual prosperity there was an urgent need to reduce operating costs and increase revenue. A target of a 40 per cent increase in productivity over five years was set. Strategies to obtain the required improvements were developed on the basis of greater involvement and increased contribution from the workforce, major changes to the mining methods and the development and application of new technology. This paper describes the organisational, operational and technological changes that have been implemented at Hilton and presents the results achieved to-date.

Jan 1, 1993

Selection of mining methods, stope dimensions and stoping sequences is usually based on comparisons with other similar orebodies or rocktypes. Rock mechanics principles assist the process, which can be further improved by application of rock mechanics' models - in particular, computer based stress analysis techniques. These models vary in capabilities and potential application but, basically, can be subdivided into techniques which only model the surface of excavations, and those which model the total volume to be analysed. To address the wide range of geometries, stoping methods and sequences, and geomechanical environments at Mount Isa Mines, a number of models have been developed. By presenting examples of their actual and potential application it is demonstrated that appropriate use of these techniques will assist in the determination of mining parameters and improve ore recovery. Examples presented cover sequencing in tabular and massive orebodies, location of shafts and shaft pillars, and backfill and hanging-wall stability. It is concluded that surface techniques are more appropriate for regional analyses and volume techniques are more suited to analyses of detailed, local geometry. Colour computer graphics should be an integral part of data preparation, and results interpretation and Presentation.

Jan 1, 1986