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By P Marianelli, J Theiler, B Beamish, A Spillman

The presence of reactive pyrite in waste rock contributes to the hazard of spontaneous combustion in emplacement facilities as it acts as an initiator of self-heating at low ambient temperatures. Organic carbon also present in the waste rocks acts as a fuel at elevated temperatures above 120°C and can lead to thermal runaway resulting in eventual ignition. A new laboratory test method (adiabatic incubation testing) is now available that can identify the presence of reactive pyrite and quantify the self-heating behaviour of the waste rock. McArthur River Mine has a waste rock profile that contains pyritic shale units, which have created spontaneous combustion events in the past. A systematic sampling and testing program is underway to characterise the spontaneous combustion hazard likelihood of the McArthur River Mine waste rocks to provide a sound database for future mine planning of the waste removal and emplacement. This paper presents some initial outcomes of this program and shows the leading practice in spontaneous combustion hazard assessment and management that has been adopted at McArthur River.CITATION:Beamish, B, Marianelli, P, Theiler, J and Spillman, A, 2018. Spontaneous combustion hazard assessment of McArthur River Mine waste rock, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 422–426 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

The 5.6 km Canning Tunnel was constructed to improve water supply from Canning Dam to the Perth metropolitan area. The site area is in the Darling Range which is essentially a laterite-capped plateau-remnant underlain by Archaean granitic rocks, intruded by dolerite. Two arrangements were available. After geotechnical investigations which included geological mapping, seismic refraction geo- physics, diamond drilling and mechanical rock testing, a single tunnel was selected in pre- ference to two short tunnels and a connecting pipeline. The tunnel is hydraulically equivalent to a fully lined tunnel 1.83 m in diameter and 5 580 m long. The alignment diverged from a straight line so that the initial upstream section was almost normal to the contours which allowed for minimal support requirements in a weathered zone. Although steel and con- crete lining was needed at both ends, the main section of the tunnel was unlined except for a concrete floor. A sand and rock trap with a capacity of 46 m3 was constructed near the outlet portal to collect debris and sand down to a size of about 2 mm. Portal excavations were in highly to completely weathered rock which extended 56 m into the tunnel at the upstream end, and 18 m at the downstream end. Conventional drilling and blasting were used for tunnel excavation with survey control by laser. Breakage lEngineering Geologist, Mines Department, Perth, W.A.

Jan 1, 1976

By C Quirion

Agnico-Eagle Mines Limited, Laronde Division, operates the deepest single-lift shaft in the western hemisphere. The initial Penna hoisting plant was designed for a production rate of 1800 tonnes per day (t/d) from a 2240 m deep shaft. Exploration success, while sinking the shaft, led to a decision in 1998 to increase the production rate to 4500 t/d of ore from a loading depth of 2200 m. The new production rate was achieved by increasing the size of the rope and reducing the rope static factor from the existing 5.0 required by regulation to a static factor using the formula 25 000/(4000 + L) contained in a draft document that would eventually become SABS 0294 in South Africa. The formula permits Laronde to use a static factor as low as 4.0. The upgraded Penna hoisting system is the first hoisting plant outside of South Africa to meet the South African requirements. This paper describes the conversion of the hoisting plant to the lower rope selection factor in the year 2000 and the operating and maintenance issues experienced since then.

Jan 1, 2005

By Ramani R. V

In this paper, a comparative performance evaluation of geostatistical, spectral, and fractal methods is made for short-scale variability prediction. The algorithms compared are: sequential Gaussian simulation method; a random fractal algorithm based on the generalised stochastic subdivision method; and a spectral simulation approach adopted for direct multi-dimensional simulation. The data for this study have been obtained from a mined out coal property. As this property was being mined, a 7315 m by 7315 m (24000 ft by 24000 ft) coal block was extensively sampled at an approximate spacing of 107 m (350 ft) and the 60-ton samples were analysed for sulphur in the 1.50 float gravity fraction. This data set is used here with the three methods to generate the simulated realisations, which are analysed for semivariogram reproduction and for simulation errors. Although all three methods converge to the true semivariogram in an average sense, the coefficient of variation of the average semivariogram for the Fourier integral method is minimum. The realisations generated by the sequential Gaussian method have minimum mean simulation error. The choice of a simulation method based on variability reproduction and simulation errors remains difficult.

Jan 1, 1995

Downhole survey uncertainties observed at various De Beers operations prompted an investigation into their possible effect on deposit shape and volume. An accurately surveyed artificial æboreholeÆ was constructed and different downhole survey instruments tested. In this way an empirically determined error range of 0.1 per cent to ten per cent was derived for downhole survey data. These survey errors were applied to an orebody model at an existing mine. Visualising the sphere of uncertainty associated with a borehole trace using a general mining package (GMP) gives an indication of possible volume variance. The resulting orebody maximum and minimum volume scenarios for three different depths (200 m, 500 m and 800 m) are presented. For certain instruments and borehole angles, the 3D positional error can be as high as 100 m at 1000 m down the hole. At depths below 200 m the resulting volume deviations can become significant for borehole survey errors exceeding 0.35 per cent. At 800 m depth the volume difference can approach 25 per cent. These figures assume that the error is compounded. The impact of these downhole survey errors is greatest for pipe-like orebodies such as porphyries and kimberlite pipes. Subhorizontal sill-like orebodies (and coal seams) will not be significantly affected by these errors. The impact of this type of survey error needs to be stated (and quantified) and is significant in JORC classification.

Jan 1, 2009

By Stone I

Tahmoor Mine is located in the southern Sydney Basin 80km south-west of Sydney and produces 1.2 MT of Bulli Coal annually. Bord and pillar methods used to date will be supplemented by a longwall system. Difficult roof conditions have been experienced since mining began in 1979. A dominantly horizontal stressfield promotes shear failure in the thinly interbedded roof sequence of shales, laminites, siltstones and fine sandstones. General roof conditions and failure characteristics are related to the angle between the roadway direction and the principal horizontal stress direction. The apparent stressfield changes direction, magnitude and the ratio of principal horizontal components across the mine workings in response to both in situ and mining induced causes. Initial roof support of 5 x 2.1 m bolts per W-strap at in intervals, with mesh, was upgraded to include RSJ's in order to support areas of failed roof. This support system was inefficient and costly. A third system of support emphasizes roof reinforcement with full resin encapsulation of 2.1 m bolts in W-straps. The number of bolts per strap (6-8), extra butterfly straps and bolts, and W-strap spacing is determined for each area by expected roof and stress conditions. Intersections are pre-bolted and ribs are supported in some areas. Pillar dimensions, order of drivage and roadway width have each been altered to improve roof control. The intensity of roof deformation at the face varies from panel to panel and causes development rates to decrease to 30% of the maximum. 1. Manager, Tahmoor Mine, Tahmoor, N.S.W. 2. Senior Geologist, BP Coal, Picton, N.S.W. Roof conditions in each area of the mine are characterised and then projected to future development areas based on the relationship between stressfield orientation, relative roadway direction and face conditions. Planning information available includes expected development rates, roof support requirements and areas of changing conditions. Future improvements of strata control involve defining support design parameters for the range of mine conditions already seen at Tahmoor.

Jan 1, 1986

The design and operating characteristics of the hydraulic cyclone elutriator were described in detail by Kelsall and McAdam (1963), and the method of operation of the commercially available version, the Cyclosizer, is described in the manufacturer's pamphlet (Anon). Complete details of the operating procedure are given in the relevant operating manual (Anon, 1964).The cyclones which form the basis of the Cyclosizer (Fig. 1) under normal operating conditions produce typical cut sizes of 44, 33, 23, 15, and 10 µm for cyclones one to five respectively for material with a specific gravity of 2·7. At the end of the selected elutriation period each sized fraction is discharged and collected for subsequent assay or analysis but all material rejected by the fifth cyclone (e.g. minus 10 \lm quartz) normally passes to waste. When this material is needed for separate study, although its amount and average analyses can be calculated by difference, it may be necessary to collect more than 250 I. of very dilute suspension, flocculate the solids, allow to settle, and decant off the supernatant liquid.This procedure is cumbersome and inconvenient and the simple technique to be described may offer some advantages. The temperature of the water fed to the Cyclosizer is maintained at a constant value for added reproducibility.PROCEDUREThe present overall treatment of the subsieve material (minus 37 \lm) fed to the Cyclosizer incorporated several refinements compared with normal operation and these may be best illustrated by anactual example. Material to be cyclosized (25 to 100 g depending on size distributIOn and specific gravity) is completely dispersed in water at 23 QC by vigorous stirrmg, using suitable dispersants if necessary, in a...

Jan 1, 1974

Longwalling has reached a high standard both in Germany and Australia and most improvements should be expected in planning, monitoring and control. Double drum shearer have electric drives to 1000 kW and automatic height control is under development. Conveyor pans to 40mm thickness and chains to 2300 kN breaking load are in use with controls for pretension and load compensation under test.Trends in support are towards two leg shields with loads to 3850 kN per leg and electrohydraulic controls. Expert systems have been devised for planning and diagnosis tasks. With increases in technical standards, staff qualification standards at rising too, drawing attention to training requirements for modem personnel.

Jan 1, 1991

By D S. Perera, P Wal, D C. Southam, J L. Lowe

The Cooperative Research Centre for Sustainable Resource Processing (CSRP) is undertaking a large research project involving partners from industry, universities and government, which aims to develop the necessary chemical and structural understanding of geopolymer materials made from waste products for them to be used to capture a significant market share of the concrete business for a given industrial region. We are investigating the suitability of a range of soluble silica-bearing waste streams for use as geopolymer concrete feedstocks. In order to utilise a variety of waste streams, either singly or blended, an understanding of the role of secondary metal ions (Fe, Ca, Mg, Ti, etc) in the geopolymerisation process is essential. A range of experimental and analytical techniques is therefore being used to better understand the structure-chemistry-property relationships of geopolymers. Currently, we are investigating geopolymers made from a variety of waste streams (fly ash, kaolinite, red mud, etc) available in the Kwinana Industrial Region, Western Australia. This paper will detail how the basic scientific research underpinning the project is vital if waste streams of varying composition are to be successfully used in a commercial concrete product and the regional synergies required to develop geopolymers from waste streams.

Jan 1, 2006

A survey of leaching systems for the dissolution of gold has been undertaken and their advantages and disadvantages evaluated both from their effectiveness at leaching and their compatibility with carbon- in-pulp (CIP) and resin-in-pulp recovery. In the near future it is almost certain that cyanidation in some form will remain the leaching system of.choice although economic and environmental pressures could see the introduction of other leaching systems particularly for treating refractory gold ores. The most likely alternative leaching systems appear to be acid chlorine, acid thiourea and ammoniacal thiosulphate. INTRODUCTION High grade reserves of readily recoverable gold ores are gradually being depleted which, inevitably, must create a greater awareness amongst gold producers, of the efficiency and, in some cases, the suitability of present day metallurgical processes for treating low grade, complex and refractory deposits. One of the key steps in the extraction of gold is the dissolution of the metal using chemical reagents which, ideally, should be cheap or recyclable, selective, non-toxic and compatible with down-stream recovery processes. In practice, meeting all these critera is difficult - if not impossible - particularly in view of the stringent environmental impact requirements which must be met Nowadays.

Jan 1, 1982

By J Arif, J Proffett

Copper and gold mineralisation at Batu Hijau is directly related to quartz veining and wall rock alteration that developed in close spatial and temporal association with multiple tonalite porphyry intrusions. To its advantage with respect to the study and better understanding of the evolution of the porphyry system, Batu Hijau has comparatively minor late alteration and mineralisation overprints. This paper summarises results of detailed geological logging, petrographic studies and geochemical analyses of diamond drill cores from the deeper sections of the Batu Hijau porphyry system (ie its roots). An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By Smith I. W

Australia has, and faces, a growing problem with regard to the ability to meet the demand for liquid fuels from indigenous petroleum resources. The position for natural gas is better but there is no room for complacency. Since the coal resources are relatively extensive, interest in the prospect of producing liquid fuels from coal is in- creasing. The approaches to the production of gaseous and liquid fuels are briefly reviewed and the present status of coal conversion technology is discussed. Many problems remain to be solved and it is estimated (in the USA) that another 8-10 years will be required before any of the processes for liquid fuel production are considered sufficiently efficient and viable to go to a demonstration plant. Coals represent complex feedstocks and the effects of variations in coal properties on oil-from-coal processes are not fully understood. The thermal efficiencies of various coal conversion processes are considered in relation to their impact on coal requirements. The production of Australia's present requirement for liquid fuels by the only commercial process in operation would require a four-fold expansion in the local consumption of coal. Any assessment of the suitability of oil-from-coal processes currently under development overseas for Austra- lian coals and requirements must take heed of the differences in coal properties and motivation. The economic via- bility of processes for producing oil from coal will continue to be uncertain because of the large difference between the World price for crude oil and the actual production cost.

Jan 1, 1975

By Belton G. R

The kinetics of the interfacial reaction of H2O on liquid silica-saturated iron silicates has been studied by means of measurement of the HDO-H2 isotope exchange reaction. The apparent first order rate constant, ka, was found to be inversely proportional to the H20/H2 ratio, consistent with two electron (melt to adsorbed/dissociating molecule) transfer mechanism and can be given by the expression In ka = -1.97 x 104/T + 1.57 - ln(pH2O/pH2), where the units for ka are mol cm -2 s-1 atm 1. The results of the current study are shown to be consistent with the indirect measurements of earlier work.

Jan 1, 1987

By Ellson I. G

Shay Gap was created for the sincrular purpose of housing, in comfort, the workforce that would be required to mine iron ore, from leases held by Goldsworthy Mining Limited, in hill country, approximately 170 kilometres east of Port Hedland in the Pilbara region of Western Australia. To combat the and environment, the Company ultimately decided to adopt a novel planning concept for the town, which had not been attempted before in Western Australia. The special problems encountered during planning, and the reservations that were expressed during construction and early settle ment, are now part of the dim past. During the three years of occupation now achieved, there has been accumulated a story of success in the provision of an acceptable alternative to modern suburbia. Not only may this be claimed, but it can also be argued that the Shay Gap concept has been a more successful solution to a real environmental problem in our arid Pilbara region than has been seen in other similar settlements.

Jan 1, 1976

By D C. Ford

The Argyle AK1 orebody was discovered in 1979 and subsequently found to be a large, economically viable reserve with high grade diamondiferous ore. Production began via an open pit operation at the end of 1985 and has continued for some 25 years to present day. This, however, will come to an end in the next few years with production moving to an underground operation via block-cave mining methods.A series of studies from 2001 - 2005 was carried out; diamond drilling commenced after approval in 2006, from an exploration drive to determine the likelihood of the current proposed block cave operation.In 2006, development of the block cave project began, in order to realise the part of the orebody below the extent of the open pit mining operation.Development of the block cave technique, comprising an undercut level beneath the target zone of the orebody with subsequent extraction level 15 - 20 m beneath, relies largely on a number of block-caving parameters (hydraulic radius, rock type, structure and orientation of stress and grade of the orebody). These all have an influence on cave ability and eventual profit of the operation. Evaluation of further potential for taking this orebody beyond the block cave phase with options such as sublevel-caving are being considered for the UG-2 portion of the resource/reserve. Diamond drilling for this work is currently under revise.The challenges faced in transitioning form the surface operations to the underground, comprising a changing workforce, converging development drives, underground aquifers, major excavations and transportation of ore via automation are intriguing.

Aug 22, 2011

A review of the most widely used global extraction sequences in sublevel is undertaken. The review includes techniques used to extract massive as well as single or multiple steeply dipping tabular orebodies. The paper also deals with thick flat lying orebodies suitable for open stoping. Techniques used to minimise the effect of stress redistributions on a global scale are discussed for all the extraction sequences analysed.

Jan 1, 2003

By G D. McDonald

Flinders Mines is an ASX300 iron ore explorer and developer with a tenement package located in the Hamersley Ranges region of Western Australia, approximately 70 km north of Tom Price. Exploration over the past three years has identified a Global Resource in excess of 740 Mt at a grade of 55.4 per cent Fe (+50 per cent Fe cut-off). This resource is spread across multiple deposits and has been divided into a number of mineralisation type domains based on geometallurgical and geochemical boundaries. These domains are comprised of transported haematite rich detrital iron deposits (DID) and goethite dominant Channel iron deposits (CID) as well as in situ bedded Brockman iron deposits (BID). On the basis of differences in physical and chemical characteristics, the DID have been divided into four discrete units. The four DID units form a stratigraphic sequence with the iron grade increasing and the contaminant concentrations decreasing with depth. The upper DID unit is lower grade and currently unlikely to provide a marketable product, without signifi cant beneficiation. The lower three DID units, together with the CID and BID, are of a higher quality and have the potential to yield marketable ore. The ability to define and recognise these different units has resulted in a more reliable and robust geological interpretation and hence greater confidence in the resulting resource model. This has been evident in the excellent conversion of inferred to indicated resources.

Jul 11, 2011

Mine evaluation methodologies are well suited to evaluating many projects in capital-intensive industries other than mining. These industries include oil, gas, power generation, transport and infrastructure projects. A case study of an open cu

Jan 1, 1998

By P Warner

Mines are often located in remote areas that are not well served by æstiffÆ power grids. Radial transmission networks, high lightning incidence (eg in South Africa the Witwatersrand experiences seven to ten strikes/km2 per year), low short circuit strengths and diesel generation are not uncommon. All these factors result in the electric power supply to many mines being unusually prone to dips and disturbances. æLegacyÆ winder drives û cyclo converters and dc drives û convert power directly from the supply to the motor, with no intermediate energy storage element. Further, they rely on the supply network for commutation and are therefore sensitive to supply voltage disturbances. There is a high probability that a dc or cyclo mine winder will trip during a supply disturbance, often resulting in lost production time and call-outs for technical staff to reset or even repair equipment. In contrast, a voltage source inverter (VSI) ac drive stores a large quantity of energy (in the dc link capacitors) and is fully self-commutating. Hence, this topology is inherently more immune to supply voltage disturbances. Indeed, vendors of ac VSI mine winders make general statements about the superior performance of their drives during supply disturbances. However, the advantages have apparently not been previously quantified. This paper compares different winder drive topologies and their sensitivity to supply disturbances, considers categories of supply disturbances and quantifies the cost of the effects on the different drive types.

Jan 1, 2005

Excavation through fill material in underground metalliferous mines is usually avoided where possible, unlike in Civil Engineering application where excavation through soft ground is normally a matter of course. In the mining situation, where excavation is normally for access only, then excavation designs are engineered for mining in hard rock, except where previous lack of forward planning has made such excavation inevitable or a mining strategy sequence necessitates some mining through fill in order to achieve optimum recovery of ore. Historically, this has been the case, because of the lack of knowledge of the support characteristics of the fill material placed underground and the lack of knowledge of the composition of the fill material as placed. The expertise and experience available from mechanised excavation techniques in Civil Engineering application (shield jacking, forepoling, spiling, and soft tunnel boring, to name a few) are available for application to the underground mining situation if the need ever arises. This paper describes the situations in underground mining development where mining through fill material is required, the different types of fill material encountered and the types of support available

Jan 1, 1981