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By Mitchell I, Gelfi P, Dunne R, Pyper R

Dump leaching at Teller in its present form began in the fourth quarter of 1988 as an adjunct to milling operations. Initial plans called for a dedicated dump leach facility capable of processing ore at an annual rate of 2.0 million tonnes. Construction of a dump leach pad, collection and process ponds, carbon adsorption system, elution plant as well as reagent addition and ancillary facilities was initiated in mid-1988. During the course of construction, additional reserves were proven. As a result, design throughput was increased to 4.0 Mtpa. Leach pad capacity and solution supply systems were upgraded to handle the larger throughput. However, the carbon adsorption/elution facilities were not upgraded due to space limitations. During 1990 it was decided to expand the dump leach operation to 6.0 Mtpa. Construction of a second leach pad was required which was initiated in early-1991. Plans were again upgraded prior to completion to a target annual throughput of 10.0 million tonnes was. A further two leach pads have been constructed. The first of these being completed during the latter part of 1992. Construction of the latest and largest pad commenced early in 1994.

Jan 1, 1994

By A G. Greenwood

Research into cemented rock fill at Mount Isa Mines Limited since 1992 is described. The key mechanisms controlling segregation during stope filling with cemented rock fill are described and include the gravity flow mechanism which is described in detail. Examples are provided to demonstrate these mechanisms. Comparisons are made between Mount Isa MinesÆ cemented rock fill and slurry-based cemented rock fills. Recent backfill stability modelling using a three-dimensional finite element program is described.

Jan 1, 1998

By Larsen D. F

Minor iron formation related base metal sulphide mineralization occurs in granulite facies metamorphic rocks of the early Proterozoic Willyama Complex. Rock sequences hosting three iron formation related Cu, Zn, Pb prospects from the Thackaringa Group (Suite 3) are described. A caparison of host rock sequences, style of mineralization and facies of iron formations suggests major differences in terms of the overall depositional environment. However, significant similarities are present with respect to the nature and distribution of iron formation facies and the occurrence of chlorite 'alteration' zones in close proximity to mineralization in all cases. The chlorite within these zones occurs in a number of diverse forms in a range of rock types. A comparison of the prospects shows that there is no evidence to indicate that the chlorite in the zones is a retrograde alteration product of former higher grade prograde mineralogies - the chlorite appears to have survived granulite facies metamorphism. The mode of occurence of the chlorite in the 'alteration' zones together with the fact that the association quartz + chlorite + magnetite + pyrite + base metals is cx rmn to all areas suggests that the chlorite is specifically related to the processes which deposited the stratiform iron formations and related sulphides. It is considered that the chlorite precursor was a prenetanorphic alteration product or chemical sediment closely related to submarine hot spring activity which was also the source for chemical sediment precursors of the iron formations, associated lode rocks and Sulphides.

Jan 1, 1983

Hydraulic transport of coal has been used for many years on the West Coast of New Zealand to extract small blocks of steeply dipping coal. Recent development at Strongman 2 Mine has seen the use of high pressure monitors to cut coal and a corresponding increase in the scale of production.This paper provides a brief introduction to hydraulic mining, describes the present system used at Strongman 2 and discusses future potential development.

Jan 1, 1998

The Bendigo goldfield is centred on the urban area of Bendigo (population approximately 60 000) in central Victoria, 130 km north west of Melbourne, Australia. Gold was discovered at Bendigo in 1851 and production continued through to 1954. The Bendigo goldfield is the second largest goldfield in total gold produced in Australia, after KalgoorlieÆs Golden Mile with a total production of 22 million oz. The geology of the Bendigo Field consists of a series of tightly folded, interbedded sandstone and shale sediments. Within the sediments the gold mineralisation is hosted in quartz reefs or ribbons closely associated with anticline axes and reverse faulting. The gold within the quartz reefs is typically both coarse grained and erratically distributed.

Jan 1, 2002

By G M. Hoffmann

Utilisation of lower grade (Jigging technology has progressed to a point where SishenÆs 50 to 60 per cent Fe run of mine (ROM) material, once considered as waste, can be beneficiated to produce a saleable 64 per cent Fe product. This has been confirmed through appropriate beneficiation testwork. Consequently, Sishen can now produce saleable product from material not currently included in the resource definition, significantly increasing the resource base of the mine and ensuring higher resource utilisation. Mine planning utilised the geological models to produce detailed planning schedules, reflecting the current and SEP plants separately, optimised to comply with product specifications of both the current and SEP plants and to confirm the viability of the low-grade resources identified as SEP feed material. The SEP product specifications have been derived by optimally matching iron ore market requirements with the revised resource base. A 64.0 per cent Fe lump product and a 63.5 per cent Fe fine product are the optimal SEP products. The SEP plant will be able to produce 10 Mtpa at an average yield of 60 per cent and a lump to fine ratio of 62:38. The plant consists of five major sections: namely crushing, material preparation, beneficiation, final product handling and quality control services. Maximum integration with the current Sishen plant was considered. Kumba currently has an agreement with Transnet to rail up to 23.5 Mtpa through the Sishen Saldanha iron ore export channel (IOEC). Transnet and Sishen Iron Ore Company have signed a Definitive Agreement that deals with the expansion of IOECÆs capacity, which increases KumbaÆs entitlement from 23.5 Mtpa to 35.0 Mtpa. The detailed enviro-legal impact assessments for the SEP indicated that the project has low enviro-legal risk as a result of it being a brownfields project incorporated into the current Sishen operations.

Jan 1, 2005

By Sen G

An amount of explosives, whether it be cylindrical, spherical, etc in configuration, with a hollow cavity in one face or end is known as a hollow or shaped charge. When this charge is initiated, a focussing of explosive energy will occur within this cavity. This focussing, or concentration of detonation products creates an intense localised force greater than just the simple detonation of a conventional explosive, (without a hollow cavity). If this hollow cavity explosive is directed against a target material this concentrated force is capable of creating a deeper penetration than the same amount of explosive without the hollow cavity. If a metallic liner material is used in the hollow cavity, upon detonation of the explosive this liner will form into a high velocity penetrating jet. Depending on the explosive type and the liner material's configuration the jet tip can travel up to 10 km/s. Linear shaped charges were developed using the abovementioned shaped charge concept but instead of being formed about an axis, they are elongated and constructed along the principal axis. Therefore instead of creating a narrow circular penetration jet, it forms a thicker planar cutting jet ideal for linear cutting purposes. Using Linear Shaped Charges (LSC) for pre-splitting is expected to result in more accurate directional fracture propagation, while minimising lateral micro fractures in the surrounding rock mass which is required to remain undamaged.

Jan 1, 1995

By Gallet M, Watsford R. M S

The 1989 feasibility study of the chessy, france, copper, zinc, pyrite and barite orebody was based upon a classical flowsheet. The flowsheet included, three stages of crushing, conventional rod and ball mill grinding in series, and sequential flotation of four products utilising conventional mechanical flotation cells. To improve the profitability of the project the partners commenced a search for ways to reduce the projected capital and operating costs of the proposed development. This paper presents the improvements in the projected capital and operating costs as a result of design and concept changes. The major changes included: ò the simplification of the crushing section with the adoption of semi autogenous grinding (SAG) milling of primary crushed ore. ò the deferral of pyrite and barite flotation circuits until market conditions were positive. ò the simplification of the flotation circuit by the use of column flotation cells for combined rougher/cleaner duty. ò the purchase of second hand equipment. The result of these changes was to reduce the capital cost estimate of the plant from US$ 21 million to US$ 11 million and operating cost estimates from US$ 18.90 to US$ 13.60 per tonne of ore for a decrease of approximately ten per cent in potential revenues.

Jan 1, 1991

EQUIPMENT TO BE DISCUSSED It is the intention of this paper to discuss the transporting of large skid mounted equipment and track machines around open cut mines. By large I mean 100 to 350 tonne capacity being trans- ported on minesite lowloaders and the capability of moving loads of 300 to 1200 tonne by other means. It is also possible to move larger loads. The main factor in transporting large loads is eco- nomics and is a balance between the cost of the transporter and the increased production from the equipment being moved. For example it could be possible to shift a 7000 tonne dragline faster than their own means of propulsion, being the "walking feet" method. However for the cost of $10 to $12,000,000.00 or more you can afford to walk the dragline and suffer the production loss. Let us concentrate on the economically realistic. BOSICH FBT MINESITE LOWLOADERS 100 TO 350 TONNE CAPACITY. Why initially consider having such a transporter? Our experience has shown that initial enquiries evolve from mines requiring to move large drills, 50 to 200 tonne weight and large hydraulic excavators or backhoes which are track mounted. The reason for shifting them is to move equipment from a mining face to enable blasting, to remove to the central workshop for repairs, overhauls and routine maintenance, to transport equip- ment from one mine face to another, and for drills, to move from one drilling pattern to the next. The cost in terms of time lost and extra wear on tracked equip- ment easily justifies the cost of the transporter. The tracks on large drills and shovels are not intended for long distance walk- ing. These tracks are designed to move the machines to position for drill holes, or moving around the mine face. Long distance travel, ie generally 1 km or more, results in overheating of track rollers, track drive components and accelerated wear on tracks.

Jan 1, 1989

By T J. Sheer

The removal of airborne pollutants from underground ventilating air is discussed. The work concentrates on the removal of CO, CO2, NOx, SO2, radon gas and respirable carbon particles. The investigation combines techniques for multiple contaminant removal using forced chemical absorption and oxidation. Both dry and wet scrubbing techniques are employed. Mixed success has been achieved in the tests carried out and this paper is seen as a progress report on the work done to date. The interference and interaction of the gases on the individual removal efficiencies is a very important factor in the finalisation of a macro air conditioner (MAC) design for treating underground ventilating air. This necessitates a specific sequence of contaminant removal. Efficiencies are discussed and recommendations made. Wet forced chemical absorption and oxidation processes, though efficient in terms of removal efficiencies, cannot be employed in the confined underground environment due to safety and health risks. Impacts on the internal water reticulation systems of the mine have been analysed to determine the effect of future large-scale macro air conditioning practices, including blow-off liquids discharged into the water circuits. To engineer the safety and health risks out of such designs can be costly and it is for these reasons the research now concentrates on dry scrubbing of the contaminants from the underground ventilating air. The paper concludes with statements on the benefits of macro air conditioning in deep hot mines, in both recirculating and series air ventilation distribution strategies. These benefits include reduced re-entry times after blasting and increased production rate opportunities.

Jan 1, 2005

The diverse nature of inadvertent mine fires does not lend them to general treatment. But evolving from the unfortunate fires over past years is a simple principle in dealing with all fires to bring combustion under control. Control, in brief, means that the products of combustion, themselves possibly still with fuel values, are not revitalised by addition of fresh air. There are problems with fire- fighting, especially with water, as this may lead to production of CO and H2. Panel ventilation upstream of the fire must be controlled to direct all air over the fire. Some advantages in fire fighting are found by the use of "sails". Early diagnosis of fires and early treatment are essential for safety of personnel and safeguarding and recovery of property. Preparedness extends to up to date documentation, but first hand knowledge also is invaluable to the diverse personnel gathered to fight a fire, and in the decision making Involved.

Jan 1, 1981

Recent geological mapping has indicated changes to the stratigraphy of the Pine Creek Geosyncline. The new stratigraphy and interpreted depositional environments are examined in relation to the distribution and genesis of stratabound mineral deposits. Basinward correlations are made with near-shore carbonate and psammite-rudite units in the Rum Jungle region. Most other units in the same region are condensed, indicating long- lived supratidal, intertidal or shallow conditions during most of the depositional cycle. Units containing most of the mineralisation represent the earliest near-shore developments of strongly reducing partly pelitic and evaporitic conditions and contain mainly uranium and base metals. Restricted distal, strongly reducing facies with associated felsic volcanics are also well mineralised, and mainly contain gold, silver and base metals, although some deposits are probably genetically related to synorogenic or postorogenic granites. Mineralisation in other facies is almost all epigenetic hydrothermal in origin, although minor mineralisation is related to volcanics, or dolomitic parts of the sequence. Areas of potential mineralisation include near-shore environments in the north, and carbonate reefs along growth faults. Two suites of postorogenic felsic volcanics and related sediments deposited in shallow water within and around northwest and east-northeast rift systems, overlie the metasediments of the Pine Creek Geosyncline in the south. The suites have potential for volcanogenic deposits, mostly of uranium, gold and copper.

Jan 1, 1984

By D V. Bright

Oroya Mining LimitedÆs Mt Gibson Gold Project, 280 km north east of Perth, is one of Western AustraliaÆs more recent discoveries of a major gold resource. Modern gold mining commenced in 1986, on a shallow laterite reserve of 6.62 million tonnes averaging 1.50 g/t gold. By the end of 1998, mining had progressed from an initial three shallow laterite pits to a series of 14 open pits with maximum depth of 100 m, on three separate trends with a combined strike length of over 10 km. The Project has yielded 868 400 ounces of gold from 16.5 million tonnes of ore at an average recovered grade of 1.64 g/t gold, from near surface laterite, supergene and primary sulfide ores. This includes a 160 m deep underground decline operation which mined 120 000 tonnes at an average grade of 9.1 g/t gold and a four million tonne Dump Leach on a synthetic base which yielded 68 900 ounces. The Project was placed on Care and Maintenance in 1999 pending drilling to refresh reserves. Hosted by strongly tectonised and altered Archaean volcanic rocks within and adjacent to a major regional shear, primary gold mineralisation occurs as structurally emplaced sulfide and quartz lodes. On the main Gibson Trend, multiple zones of mineralisation occur within a zone up to 600 m in overall width. The overall footprint of known mineralisation exceeds 20 km2 and the potentially mineralised domain exceeds 100 km2. The current estimate of a combined resource of 9.4 million tonnes averaging 2.47 g/t gold (749 500 ounces) is derived from a database of 10 500 drill holes, of which only four per cent test below 100 m vertical depth. Ore envelopes which remain open at depth and major gaps in the drilling pattern beyond the currently defined resources promise straightforward potential to define additional resources. Oroya Mining Limited and its joint venture partner Barrick Australia are targeting a major gold mining operation from this potentially world-class mineralised system. Oroya has the exclusive right to produce up to 500 000 ounces and is working toward the completion of a feasibility study into a resumption of mining using the existing 1986-built 1 Mtpa processing plant. The joint venture is in the early stages of testing the depth and lateral potential of the Mt Gibson mineralised system. Mining options currently under review include progressive open pit extension and amalgamation leading to one or more large open pits, and underground operations. It is too early in the development of the Project to offer definitive economic models of potential large-scale mining operations.

Jan 1, 2003

By N McKenzie, F Brodbeck

The North-South Bypass Tunnel is the first project to get underway as part of BrisbaneÆs transport plan, which aims to improve the urban road network. The total length to be excavated is 6.8 km, which includes 4.8 km of driven tunnel and associated road connections. Construction commenced in August 2006 with project completion targeted well before the contractual completion date of October 2010. Due to the local geology, in particular the hard Brisbane tuff and neranleigh-fernvale formation, a combination of tunnel excavation methods are used. The majority of the tunnel is excavated by two tunnel boring machines which have a rate of progress of 16 - 20 m per day in rock having a compressive strength of between 80 and 150 MPa. Ten roadheaders operate at a rate of up to 2 m per day excavating the remaining tunnels, such as ramps, access tunnels, cross passages and merges. The tunnel team are managing the challenges and complexities associated with tunnelling through the hard Brisbane rock. A major challenge arose during the planning of the initial mainline excavation underneath the Royal National Association Showground in Bowen Hills. This section contains low rock cover and historical maps indicate that the showground is located within a former topographic depression (alluvial valley), which a creek once flowed through.Due to traffic merge design requirements, both tunnel boring machine (TBM) and roadheader excavation methods were required to be used in this challenging geological profile. The answer was to stabilise the alluvium above both TBM section tunnels from the surface prior to excavation and to operate the TBM in single shield mode with immediate grouting of annular void from the tail shield. In addition, the roadheader section of tunnel required additional support by spiles and canopy tubes installed from the tunnel face.

Jan 1, 2008

By Roach C

Exploration on the Callide Coalfield by Thiess Bros. Pty. Limited had reached the stage in mid 1976 where there was a need for a comprehensive appraisal of the coalfield geology. Exploration strategy in 1977 - 1978 was defined by the selection of the most attractive targets. All available literature, reports and plans were reviewed and borehole records assessed. The geology of the coalfield was placed in its regional setting and the genesis of the Callide Coal Measures described in a structural and sedimentological context. Their general form and extent was then examined by the technique of stratigraphic analysis through the interpolation and extrapolation of the available data. A "localized" reserve classification was drawn up and reasonable estimates of the various geological reserves produced, in terms of their reliability and depth of overburden. Quality trend maps were also produced. The resultant "base map" was virtually a summation of all the information to June, 1977, and the basis for the exploration programme in the 1977 - 1978 financial year. The technique allowed for "base maps" to be produced at almost any stage, each one a refinement of its Predecessor.

Jan 1, 1978

By P Pelletier, J Tessier, C Duchesne

This paper summarises research into the study of the control of flotation processes based on froth images. A review of the froth flotation operation background and the relevance and role of the froth phase are presented. The use of numerical image analysis techniques for the extraction of significant patterns from industrial flotation froths is discussed. First, the froth was analysed by the use of the multivariate image analysis (MIA) method to extract the spectral variation contained in a RBG image. The partial least squares (PLS) method was applied to develop an empirical model for the prediction of froth grade. The results of this application are illustrated using an industrial case study. Second, the froth was also analysed by grey-level co-occurrence matrix (GLCM) and wavelet transform analysis (WTA) to extract features related more to morphological aspects. Since there is useful information hidden in froth texture, these methods are used as texture descriptor to classify different types of froths. They also provide qualitative information on the changes in the visual appearance of the froth. The pros and the cons of those methods are highlighted. Third, a control strategy based on a froth structure indicator was developed and implemented on an industrial zinc flotation circuit. The feedback controller uses the reagent flow-rate in order to maintain the froth structure at its set point. Process improvements obtained from the implemented control strategy are highlighted. Finally, the feasibility of implementing a hybrid control strategy consisting in a froth structure supervision controller based on the froth concentrate grade estimated by MIA and recovery inferred by image analysis is discussed.

Jan 1, 2005

The design of mine ventilation systems for the BHP Steel Division Collieries is based on the acquisition of ventilation survey data for the establishment of a realistic computer net- work model. The branches which form the net- work for the computer models are calculated from a range of resistance factors incorporat- ing both a frictional and shock loss component. Since shock losses can account for up to 30 per cent of the total energy losses in mine airways the use of friction factors alone without accounting for shock losses will result in the choosing of an insufficiently performing fan. Published tables of friction factors have in- variably been taken from metalliferous or single entry studies and consequently are not reliable for Australia's mining conditions where multiple entries with regularly spaced cut-throughs are the normal practice. Typical resistance factors for roadways of rectangular cross-section 5.5 m x 2.0 m, with coal sides, have been found to vary from 0.11 Ns2/m8/km where no timber supports are used, to 0.98 Ns2/m8/km where double centre legging together with wooden chocks is used. In addition to the range of resistance factors due to varying support methods, the nature of use for a roadway is very significant because of the condition of repair and upkeep maintained.

Jan 1, 1983

During late 1953 and early 1954, tests were carried out in Sydney metropolitan brickpits in order to determine if some improvement might not be effected in the personal shock, fly rock and possible ground displacement accompanying daily blasting occurrences in the numerous quarrying activities of the metropolitan area. As a result of this preliminary work (Reid, 1954), the Department of Mines decided to further investigate the problem with a view to placing this type of blasting on a sound economical and safe basis for both operator and nearby residents alike. To assist in the work, a Cambridge Universal vibrograph was acquired.Human safety was the first consideration followed by property damage to homes and factories in the extractive areas. Although most of the actual field work has been confined to the Sydney metropolitan area and in particular to the large clay-shale quarries, many cities and country towns have blasting problems associated with the extractive industries, engineering projects both above and below ground level, and in building excavations to which the results may apply.The following figures illustrate how much activity of this type is located around cities and towns:Sydney Metropolitan Area:

Jan 1, 1958

The series of events leading to the adoption of more complex flotation circuits for coal have been reviewed. In essence, it has been concluded that ac- ceptable overall flotation recovery will only be obtained when efficient distri- bution of collector over all the component feed size fractions is ensured. The achievement of this goal is most likely to be obtained by feed classification and separate flotation of appropriate size fractions. The adoption of such a phil- osophy, however, imposes a number of process problems of both a chemical and an engineering nature. Some of these problems have been identified and possible solutions discussed. A case is emerging for the development of a new generation of flotation cells designed specifically for the flotation of classified coal and for the development of a series of novel re- agents which have the propensity to float middling particles.

Jan 1, 1984

By J Williams

The recent drought has highlighted the finite nature of AustraliaÆs divertible water resources. According to AustraliaÆs recently completed National Land and Water Resources Audit, development of water resources in southern Australia has reached or exceeded sustainable extraction limits. Similarly, 161 out of 538 groundwater management units are either totally allocated or already over allocated. Whilst mining only uses about three per cent of diverted water resources, water scarcity may be a major factor that determines whether potential mines can be developed in the future. Furthermore, the development of extraction and processing facilities that limit water use and maximise the re-use the waste water streams will be even more fundamental features of the mining industry in the 21st century than they are at present. There are encouraging examples where innovative water re-use technologies are significantly reducing the water used per unit of mined product. Whilst mining in the areas of Australia draining to the tropical seas may be less constrained by a current lack of water (60 per cent of divertible water resources drain into the Timor Sea, Gulf of Carpentaria and north east Coral Sea), it is highly probable that there will be increasing demand for these waters from the irrigation industry, whilst pressure will also be applied to ensure that environmental flows that benefit the coastal fishing and prawn industries are maintained. In the Great Artesian Basin, current research is demonstrating that the groundwaters are being recharged at rates considerably lower than current extraction. Whilst some other groundwater basins in arid and semi-arid Australia have currently untapped resources, these water are often relatively saline and/or may be intimately linked with key ecosystems in discharge areas. This paper presents an overview of the current state of our water resources and examines some of the key water use issues including allocation, use and reuse, environmental flows and competing demands on the resource that will ensure that water issues remain high on the policy agenda for mining, irrigation and other water users.

Jan 1, 2003