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By T Baumgartl, B Richards

Covers on waste rock and tailings remain the primary choice for closure planning where the purpose is to create an environment where water ingress into reactive material can be controlled and/or prevented. In semi-arid and arid environments, dry cover systems are the preferred option with the design intention to absorb rainfall and to prevent deep drainage. Although the average amount of rain typical for semi-arid environments is relatively low and evaporative demand is high, the seasonal and annual distribution may vary greatly. Rocky substrates are often the only choice for the construction of covers due to economic constraints or availability of suitable materials. While the water holding capacity may be suitable for the application of a dry cover design in arid and semi-arid climates, some of these covers bear the risk of preferential water flow when rain events are intensive or occurring at high frequency. The objective of this presentation is to demonstrate the occurrence of preferential flow through rock containing dry cover systems. A regional classification for the applicability of dry covers is attempted to delineate those regions of Australia where the characteristic of the rainfall pattern increases the risk of failure for dry cover designs. CITATION:Baumgartl, T and Richards, B, 2016. Rainfall patterns rather than climate classification control cover design for closure, in Proceedings Life-of-Mine 2016 Conference, pp 89–92 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By Fabjanczyk MW, Aziz NI, Hii J

The paper presents the results of a series of pull out tests performed on roof reinforcement systems currently being adopted in mines in Australia 7mm wire, dividag bar, 15.2mm strand cable, and birdcage cable. The study also investigated the load deformation chara- cteristics and the various design parameters controlling the effectiveness of a cable-grout system. Suggestions for continued work are Highlighted.

Jan 1, 1986

By Trueman R

If continuous mining systems are to be successfully applied in metalliferous mines then reliable models will be needed to predict rock cutting machine advance and tool wear rates for effective machine selection before mining commences. Many of the predictive models developed to assess cuttability in situ are over-simplistic. As a result they tend to be both site and/or machine specific. Nevertheless very detailed models have been developed for full face machines which are capable of accurate cuttability predictions in a variety of rock mass conditions and for a variety of machine and tool configurations. However, models to predict productivity and tool consumption for partial face machines are not as well advanced. There is a need to develop reliable models for partial face machines such as Roadheaders, the Robbins Mobile Miner and the HDRK-Wirth CMM, as these types of machine are likely to predominate in a mining environment. The paper outlines the current state-of-the-art for predicting cutting machine performance and the work being carried out within the Centre for Mining Technology and Equipment (CMTE), in collaboration with the Australian mining industry, to advance our capability in this area.

Jan 1, 1995

General Gold was discovered in quartz veins at Wiluna in 1896, and the first lode was discovered in 1904. Since 1896, some 2.5 million ounces of gold have been produced from the Wiluna area. The mining operations at Wiluna are 100 per cent owned by Wiluna Gold Pty Ltd, a wholly owned subsidiary of Wiluna Mines Ltd. Oxide and sulphide gold ore is extracted by conventional open pit mining techniques, and ran-of-mine ore is processed through two separate circuits. The oxide circuit has a capacity to treat 600 0(X) tonnes per annum and the sulphide circuit has a capacity to treat 400 (XX) tonnes per annum. Additional gold is won by dump leaching sub-grade oxidised ore and by retreating of primary ore flotation tailings from previous operations. Testwork carried out in 1990 indicated the viability of leaching dumps of run-of-mine oxide ore, and in June 1991 Signet Engineering of Perth, WA, was awarded an EPCM contract to construct a nominal 2.5 million tonne dump leach facility, for a total construction estimate of 51.75 million.

Jan 1, 1994

The Manto Verde copper mine (Atacama Region, Chile) is due to go into production in 1996. It will produce 40 000 tonne/year of copper cathode by heap leaching/SX-EW. Mineralogical studies were undertaken in conjunction with the metallurgical testwork program to characterise the ore and its response to leaching by dilute sulphuric acid. The leachable copper mineralogy is dominated by the oxide copper minerals: brochantite and malachite with minor chrysocolla and atacamite. The gangue minerals include abundant orthoclase, specularite, quartz and chlorite with minor muscovite and trace smectite clay, calcite and limonite. The study showed that complete or partial decomposition of calcite, chlorite, smectite and wad consumed acid and generated solution impurities (Ca2+, Fe2+, Mg2+, A13+, K+, Si4+ and Mn4+2+ ). Although these were manageable at Manto Verde, their uncontrolled build-up could have affected the operation in several ways: the degradation of heap penneability and fonnation of crud in the SX plant from the precipitation of gypsum, goethite, colloidal silica and jarosite; and the entrainment of contaminated pregnant leach solution in the SX organic resulting in the transfer of impurities to the electrolyte and subsequent effects on cathode quality and electrowinning efficiency. In conclusion, process mineralogy played an important role in understanding and managing potential mineral-related problems in the heap leaching and SX-EW recovery of Manto Verde ore.

Jan 1, 1994

The light microscopic study of the physical structures of coal and associated mineral matter is an important technique in providing information on the characterisitics and possible behaviour of coals in industrial processes. However the ultrafine nature of coal and mineral particles together with the limits of resolution of the light microscope restrict such studies. Scanning electron microscopy (SEM)with its better resolution and higher magnifications is the means by which further information on coal properties can be obtained. An associated energy dispersive X-ray specrometry (EDS) method allows non-destructive in-situ chemical analyses to be carried out at the same time.

Jan 1, 1989

By Baafi E. Y

A heuristic approach for the optimisation of the stope geometry is presented. The heuristic method uses economic model of a given deposit to search for the best combination of mining blocks that results in the maximum profit while imposing geo

Jan 1, 1998

Most text books on rock blasting claim that the relationship between burden and borehole diameter is linear. The statistical calculation presented here with real values from one hundred open pit and underground mines indicates that the relationship is exponential. For underground mines the burdens are consistently lower than those for open pit mines because of higher ore densities, greater confinement in blasting, and finally greater demand for well fragmented rock. The results shown in this paper are recommended to be considered in basic teaching of rock blasting technique. The formulas can be used for a first rough estimation of practical burden and spacing. The formulas do not however give any information about the fragmentation. For that purpose it is necessary to use other formulas not described in this paper.

Jan 1, 1990

By Fejes A. J

The U.S. Bureau of Mines installed surface and subsurface instruments at a mine site in Colorado to monitor and characterize the overburden response to longwall mining. Instrumentation included a time-domain reflectometry (TDR) cable, a multiple-point borehole extensometer (MPBX), vertical- deformation surface monuments, and in-mine pressure cells for monitoring abutment, pillar, and gob loads with respect to the longwall face position. The purpose of the study was to collect data that could be analyzed to correlate the design of the mine layout to the resulting overburden failure response. Determining the extent of caving and fracturing is important in the and and semiarid Western United States because of the possible consequences to the fragile underground hydrologic systems upon which the land owners and users depend. This study is unique from past investigations because the overburden contains massive sandstone members that impose special conditions on the caving process and pressure redistribution above the longwall panels. This paper presents the results of this correlation study.

Jan 1, 1992

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

By Gooday PE, Brech GE

Ore reserve categories used by Pancontinental Mining fall into one of three fundamental groupings: Geological In Situ Reserves Mining Reserves Production Estimates The first of these describes the total reserve within stated parameters without implication as to its mineability. The second is that part of the Geological In Situ Reserve which is considered mineable under a specific mining plan. The third is the Mining Reserve adjusted with appropriate dilution and recovery factors and thus represents the best estimate of the tonnage and grade of production. This practical three category system mirrors the standard steps traditionally taken in ore reserve estimation and readily conveys the basis of the estimates. An important, but secondary classification can be added to qualify the level of confidence in these estimates using the terms: Proved (or Measured) Probable (or Indicated) Possible (or Inferred) These terms can be applied to any of the fundamental groupings, but it is generally implicit that the level of detail required to produce meaningful Mining Reserves or Production Estimates would require the basic Geological Reserve to be at a Proved or at least Probable level of confidence. The application of these classification systems by Pancontinental is illustrated by reference to the Paddington Gold Project. The methods of calculation are described including the use of geostatistics. Reconciliations of actual production with predictions from reserves are carried out monthly and annually. To date there has been an excellent correlation with Production Estimates, based on both manual and geostatistical calculations.

Jan 1, 1987

By Feebrey CA, Duncan RA

The Ebor Volcano in northeastern New South Wales is an eroded example of a central-type intraplate volcanic-intrusive complex. It is of Miocene age (19-20 Ma) and has similarities to other central-type volcanoes in eastern Australia which may represent manifestations of sub-lithospheric hotspot activity. Thick lava flows are exposed around the Great Escarpment and are dominated by a tholeiitic basaltic suite, ranging from ol-tholeiite to qz-tholeiite to icelandite with ages of 19.2-19.6 Ma. On its western edge, the tholeiitic lava suite probably overlies remnants of basanite flows belonging to the Eocene (-48 Ma) Doughboy province, but elsewhere, minor alkaline basaltic lavas may be coeval with the tholeiitic suite. Several felsic bodies were emplaced into the volcano at -19.0-19.2 Ma and include subalkaline and peralkaline types. The Crescent Complex is a Miocene-age, strongly differentiated mafic to felsic intrusion in basement rocks and centrally located in pre-erosion reconstructions of the Ebor Volcano. It is interpreted to be a major feeder for the tholeiitic lavas based on age and composition. Evolution of the dominant tholeiitic suite proceeded from a parental ol-tholeiite magma, through qz-tholeiite, icelandite and small volumes of felsic rocks by fractionation of plagioclase, olivine, clinopyroxene and titanomagnetite, accompanied by enrichment of SiO2, F,FeO/MgO, alkalies and HFSE.

Jan 1, 1995

By Garrigan J. S, Oakes I

Current operating practice in a plant commissioned some five years ago to treat ferritic zinc plant residue by the "Jarosite" process is described. Major problems overcome include obtaining reliable pH measurements at 100¦C, prevention of scale build up in spent electrolyte heaters, blinding of jarosite filter cloths and the deposition of gypsum in filter presses.

Jan 1, 1977

By Paine GG

The Kidston Gold Mine commenced mining in 1984 and current annual production is 12 million tonnes, increasing in 1990 to 18 million tonnes. Mill throughout per year is 4 million tonnes with the balance of material being waste. The operation is a conventional hard rock open pit truck and shovel operation mining 12 metre benches. Buffer blasting is utilized to minimize post blast movement of the broken rock to maintain grade control.

Jan 1, 1988

By Green S, McKernan, Skrypniuk

In November 1996, Boddington Gold Mine (BGM) began the implementation of an expert system. The objective of the expert system was to improve plant efficiency by developing an `operator best practice' control philosophy for the grinding circuit

Jan 1, 1997

By Lovitt M

Ora Banda Gold Mine is located in the Eastern Goldfields of Western Australia. Mining is carried out underground by sublevel open sloping resulting in large open stopes. A Mass Blast of approximately 250 000 tonnes was carried out in July 1994 to recover a rib pillar between two stopes, and the crown pillar between the underground mine and the abandoned open pit above. Strategic development within 50 m of the blast consisted of two ventilation shafts and the main decline. This development required careful design and prediction of the blast results. This paper describes the design of the blast, the prediction of the likely effects, the measures taken to reduce the risk to important development, and the results of the blast.

Jan 1, 1995

The orebodies at Kambalda are complexly faulted, folded and intruded. It is realized that the ore reserve calculations will be wrong and steps are taken to minimise the errors. The calculations are a combination of computer data handling and manual input. Initially Geological Ore Reserves are calculated and then production data and experience are used to produce a Planned Mining Reserve. At all stages maximum professional judgement is incorporated. The basis of the calculation is the polygonal method of area estimation, and production reconciliations together with the style of data available indicate that it is a most suitable technique. It is also a tech- nique that is easily communicated to all levels from operators to management.

Jan 1, 1979

By Renwick MT

Two innovative ground reinforcement products have been developed for use in the mining industry. One of these products is a high strength polyethylene (HOPE) bar for use as a rib bolt in underground coal mining and as a corrosion proof tendon in open pit mines. The other product is a cable bolt (Ultrastrand) which demonstrates enhanced load transfer and is available in continuous lengths. Ultrastrand's exceptional in- situ performance and versatility makes it ideal for mechanised installation in both underground and surface mining operations. Details of these products are presented and results from labortaory and field trials are discussed.

Jan 1, 1992

An ongoing research program into surface subsidence over Room and Pillar coal mining is described. A subsidence monitoring network has been established for one Room and Pillar mine in the West Moreton Coal Field of South East Queensland, at which pillar extraction is being conducted. The maximum measured subsidence to 28 January 1986 was 638 mm, with movement continuing. Analysis of the monitoring data with view to application of the subsidence pre- diction theory developed by Kowalczyk (1972) is discussed. The Kowalczyk theory provides predictions of subsidence depression, slope of surface, horizontal displacement, surface curvature and horizontal strain, for both the Partial and Total Settlement cases. The development of subsidence with time is also investigated and a preliminary analysis conducted.

Jan 1, 1986

The Woodcutters deposit, 65 km south- southeast of Darwin, N.T., consists of a series of veins of pyrite, sphalerite, and galena with some silver, cadmium, antimony, and arsenic minerals. The veins are hosted by the Early Proterozoic Whites Formation, a sequence of black slates with interbedded carbonate rocks and minor ash tuffs. The known orebodies occur about 300 to 500 metres above the contact of Whites Formation with the underlying Coomalie Dolomite, which consists of dolomite and magne- site. The stratigraphic setting is lithologic- ally similar to that of the Mt. Isa deposit, Queensland. The orebodies are replacement veins occ- urring along fault and dyke structures which are sub-parallel to the axes of a double-nosed faulted anticline. The orebodies are in part associated with two unusual carbonatized lam- prophyric dykes. The dykes were intruded after the fold and its slaty cleavage were formed. The ore has replaced the dykes and host rocks and is therefore late-stage hydrothermal miner- alization. The known orebodies are open at depth. A "bonanza" of high-grade ore occurs at the upper part of the largest orebody and is currently the subject of an open cut mine planning study by a consortium of companies headed by Nicron Resources Ltd.

Jan 1, 1984