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Cable bolts have been used extensively in the development of the footwall of the Mt Whaleback Mine as a part of the ground improvement program since 1986. High tensile seven wire stress relieved steel strand similar to that used in pre-stressed concrete and grouted in place with sulphate resistant cement have been employed for rock-mass reinforcement.Most of the footwall is developed in Mt McRae Shale which contains a 20 m thick pyritic shale layer 14 m below the ore/waste contact. Due to extensive folding of the footwall rocks, the pyritic shale layer regularly occurs on, or close to the pit slope. Rain water run-off seeping through pyritic shale becomes acidic to the extent where its pH value can be as low as 1.5.

Jan 1, 1992

This report chronicles the historical development of longwall mining in the United States and speculates on future developments to the turn of the century. Five eras of technological development during the modern period are described and analyzed. These eras discuss the development of (1) mechanized extraction, (2) self advancing roof supports, (3) high capacity roof supports, (4) shield supports, and (5) system automation. Current trends are analyzed in terms of: longwall utilization, production capability, support capacity, face widths, and new technological developments. From these analyses, the future of longwall mining to the year 2000 is speculated. It is concluded that longwall mining will continue to grow in importance during the next decade and that the next major technological milestone will be the realization of a fully automated longwall mining system.

Jan 1, 1992

By Sennitt C. M, Hartley J. S

The Twin Hills Gold Deposit is an example of a preserved, high level, epithermal system, with mineralisation introduced contemporaneous with deposition. The deposit is hosted within sediments of the Late Devonian to Early Carboniferous Saint Anns Formation, of Cycle 1 Drummond Basin stratigraphy, situated in central Queensland. Prior to epithermal activity in the Twin Hills region, a lacustrine fan delta depositional environment existed, together with minor tuffaceous activity. An and palaeo climate, with occasional periods of torrential rainfall, together with a basin with faulted margins, allowed alluvial fan prograda- tion. Cyclical repetitions of the fan indicate repeated faulting and seismic activity took place during deposition. Significant gold mineralisation was first intersected at Twin Hills by Metana Minerals NL in 1988, after drill testing a "blind" target outlined by geological mapping and bedrock geochemistry.

Jan 1, 1991

By R McConnochie, J V. Rowland, J L. Mauk

The Sovereign prospect in the lower Waitekauri Valley of the southern Hauraki Goldfield occurs in daciterhyolite flows and volcanic breccias of the Waipupu Formation. The lower Waitekauri Valley contains a series of NE to NNE-trending normal faults, and the Sovereign prospect lies in a NW-striking graben. The structure of the Sovereign prospect is complex. NE to NNE-trending veins and normal faults dominate the area, however WWNW and N to S-trending structures occur locally. Kinematic analysis of these structures indicates predominantly dip-slip movement, with a local strike-slip component. At least two sets of veins occur in the area: 1.        steeply dipping veins; and 2.       low angle veins, which cross-cut and locally offset the steeper dipping        vein set. Mineralization appears to have formed during normal faulting in an extensional regime.

Jan 1, 2007

By Hatherly P, Dunn P

There are- several in-seam coal research projects currently under investigation by the Cooperative Research Centre for Mining Technology and Equipment (CMTE). The overall aim of the projects is to produce new technologies to enhance safety and the efficiency of in-seam gas drainage drilling. Results from high pressure waterjet rotary drilling trials indicate that by applying high pressure water to a rotary drill bit, the hole can be drilled to follow the planned trajectory very closely. Steerable drill bits for drilling long holes (>1 km) have been produced and trialed. A flexible high speed drilling system provides a capacity for rapid in-seam drilling, particularly suited to cross panel drainage. Geophysical tools are being developed to provide a geological steering capability and a better understanding of potential gas outbursts zones.

Jan 1, 1998

The iron ore mining operations carried out by Goldsworthy Mining Limited at Golds- worthy, Shay Gap and Sunrise Hill, in the Pilbara region of the North-West of Western Australia, are unusual insofar as the ore reserves occur in a number of widely separated and relatively small deposits, requiring deep mining below the water table, and even below sea level at the Goldsworthy pit. This paper has been prepared to describe some of the problems associated with these deep open cut mines, and the technology employed to overcome them, in order to provide an efficient and economical operation. The problems discussed are: 1. Development of the Dewatering System for the Goldsworthy Mine. 2. The Stability of Pit Slopes at the Goldsworthy and Shay Gap Mines. 3. Development of Diesel Electric Trucks for Lonq Uphill Hauls.

Jan 1, 1979

By Ramsay WRH

The Mount Stavely Volcanic Complex compri- ses one of a number of northerly trending fault bounded greenstone occurrences in Western Vict- oria, of probable Cambrian or older age. The greenstone belt is coincident with several linear positive aeromagnetic anomalies, which outline the surface and subsurface extensions of these greenstones. Mapping at Mount Stavely has identified serpentinite, variolitic basalt, two-pyroxene and pyroxene-hornblende andesite, dacite, rhyodacite and their pyroclastic equiv- alents. Chemically and mineralogically the volcanics constitute a calc-alkaline assemblage. The mineral potential of the region has been enhanced following a discovery by Pennzoil of Australia Limited near Ararat, of sulphide min- eralisation containing approximately 1 million tonnes at 2.7 percent copper. The volcanic environment of the Mount Stavely Volcanic Complex is discussed in terms of similar environments found in Canada.

Jan 1, 1982

By Zamora C

The performance of a system for detecting the onset of overloads on rod mills is described. The system has bee,, tested at CODELCO E1 Salvador Concentrator where, due t,, variations on size distribution of the copper ore feed, th' rod mill is frequently subject to overloads. The main inpur signal to the system is the rod mill sound, after being measured and analog conditioned. This signal and othe signals measuring the fresh ore feed and the mill watt addition are fed to a computer containing a simpl mathematical model. The model parameters are empiricall estimated and an analog output signal is generated, whic gives an early prediction of the overload condition. The experimental results described in this paper show that the overload condition may be predicted with an anticipation of about three minutes.

Jan 1, 1985

By C Gourdon

The present study concerns a new type of mixer-settler unit where coalescence is promoted by means of the phase inversion method (MSPI). Using two different systems (alkaline etching solution û LIX 54 in kerosene and acidic aqueous solution û LIX 984 in kerosene) the influence of the total flowrate, the A/O phase ratio and the hydrodynamic conditions in the nozzles of the scattering device on the extraction and separation efficiencies are studied. Two modes of operation are clearly outlined and a theoretical model predicting the separation efficiency is proposed and compared to experimental results. A comparison between mixer-settlers with classic decanters and the MSPI unit has demonstrated the advantages of the latter where throughputs in the range 20 -25 m3.m-2h-1 can be easily realised.

Jan 1, 2000

By Sullivan BJK

The 1100 orebody is a massive copper sul- phide orebody which contains a major portion of the Isa Mine copper ore reserves of 130 million tonnes at 3.2%. The underground mining of a deposit as large as the 1100 orebody is technologically a complex operation as extraction strategies have to be evaluated with reference to 1. rock mechanics considerations, 2. safety and environmental standards, 3. production and operating require- ments and 4. metal recovery and costs. The mining philosophy in the orebody has undergone considerable change over the past five years as a result of experience and improved technology. At this stage, primary stopes are extracted by high rise sublevel open stoping and pillars by slot and mass blast drawn either under rock fill or as an open Stope.

Jan 1, 1978

By V P. Beskrovnaya

Tests for the development of a metals recovery technology from samples of a Russian gold-bismuth deposit were carried out. Gold, silver and bismuth assay reported 5.6 g/t, 3.0 g/t and 0.08 per cent, respectively. Two flow sheet options were pilot plant tested: gravity/cyanidation of gravity tailings with subsequent flotation of cyanidation/carbon-in-pulp (CIP) tailings, and gravity/flotation concentration with cyanidation/CIP of concentrates. Option 1 results showed lower gold, silver and bismuth recoveries (81.3 per cent Au, 55 per cent Ag and 74.0 per cent Bi) due to low flotation efficiency for cyanidation tailings. Therefore, a flow sheet involving gravity/flotation concentration to produce bismuth-gold concentrates (0.8 per cent Bi) with subsequent cyanidation/CIP was recommended. Gold, silver and bismuth recoveries obtained by this method to the combined gravity/flotation concentrate were 90.2 per cent Au, 83.3 per cent Ag and 80.2 per cent Bi of the ore, respectively. Overall gold, silver and bismuth recoveries were 83.0 per cent Au, 40.5 per cent Ag and 80.2 per cent Bi, respectively. Gold and silver recoveries to the cathode precipitate were 92 per cent Au and 48.6 per cent Ag (per operation). Reagents consumed for flotation were 0.1 kg lead acetate/t ore, 0.4 kg butyl xanthate/t ore, 0.2 kg T-80 frother/t ore, 0.02 kg sodium hexametaphosphate/t ore, 0.15 kg copper sulfate/t ore. Reagents consumption for cyanidation was 0.42 - 0.48 kg NaCN/t ore and 0.2 kg CaO/t ore. It was recommended to deliver bismuth concentrates after hydrometallurgical treatment to a smelter. Overall bismuth recovery including bismuth recovery achieved by pyrometallurgy was 60.0 per cent. However, it was obvious that delivery of bismuth concentrates to a smelter and their commercial treatment would be very expensive due to relatively high mass pull of bismuth concentrates (7.6 per cent of the ore weight). For this reason, thiourea leaching and hydrochloric acid leaching with subsequent cyanidation/CIP were investigated as alternatives to cyanide leaching. These two alternatives were proposed to enable optimal recovery of valuable metals from concentrates on-site. Recoveries obtained by thiourea leaching were 91.2 per cent Au, 90.5 - 91.9 per cent Bi and 77.0 - 78.1 per cent Ag. However, that method required considerable capital and operating costs. As an alternative, hydrochloric acid leaching with subsequent cyanidation was investigated. Test results showed improved gold, bismuth and silver recoveries, which were 94 - 95.9 Au per cent, 94 - 96 Bi per cent and 76 - 78 Ag per cent, respectively. Hydrochloric acid consumption was 100 kg/t concentrate or 7.6 kg/t ore. Current efficiency during electrowinning was about eight to 12 per cent. A recommended flow sheet involving hydrochloric acid leaching of concentrates, electrowinning of bismuth from solutions, recycling solutions after electrowinning and cyanidation of hydrochloric acid leaching cakes is described. Overall recoveries achieved by the proposed flow sheet were as follows: 84.8 - 86.5 Au per cent, 75.8 - 76.9 Bi per cent and 63.2 - 64.9 Ag per cent. Based on results from these tests, initial data for a bankable feasibility study and plant designing were developed.

Jan 1, 2007

By Brockway DJ, Holmes RJ

A natural gamma-ray gauge has been devel- oped for discriminating overburden and inter- seam sediment from low ash coal located on a moving conveyor belt. It is based on the difference in natural radioactivity of the sediment and overburden compared with the low ash coal, which is detected with a highly ef- ficient "Polyscin" NaI(T1) gamma-ray detector located underneath the conveyor. Gauges have been successfully installed on the bucket wheel boom of the two coal dredgers at the Loy Yang Open Cut. They are used to warn dredger operators that they are digging overburden or sediment and that action is required to avoid the sediment or divert it to the waste dump rather than send it to the coal bunkers at the power station.

Jan 1, 1987

By Parker RL

A 250 tons per day ammonia-ammonium carbonate leaching plant is now being operated by Samin Limited, to extract copper from the oxidised ores at the Burra mine. This forms the first stage of a plant, which will eventually have a capacity in excess of 1,000 tons per day. The article reviews the history of the mines at Burra and the metallurgical studies which have been undertaken since the old mines closed in 1917, in an endeavour to recover the copper from the low-grade deposits left by the original miners. The reasons why an ammonia leaching process was selected instead of the conventional flotation or acid leaching methods are discussed. The paper concludes with a detailed description of the plant and the basis on which it was designed.

Jan 1, 1971

By Thornber MR, Davidson LR

The cause of spontaneous combustion of pyritic black shale has been studied by calorimetry and other techniques. The conditions required for ignition to occur are: 1. A critical mass of pyritic black shale. 2. Acidity. 3. Fine shale particle size. 4. A high ambient temperature. 5. The exclusion of air during the preparation of a calorimeter charge. The reaction is characterised by an initial incubation period during which an unknown phase is produced. The build up and oxidation of this phase results in a chain reaction culminating in ignition. The mechanism is believed to involve the interaction of pyrite, sulphuric acid, ferrous sulphate, or meta-stable oxysulphates, with ammonium nitrate. The recommended strategy for prevention of premature detonation is to neutralise the acids in the shale with quick and slow release alkaline materials.

Jan 1, 1986

By Quayle J. E

This paper covers period from 1973 through to 1988 and the mines of West Coast Mines, Elur Mine, North Mine and Risdon Zinc Smelter, now all part of the Pasminco Group. During this period, optimisation started with one mine (West Coast Mines) producing four Product concentrates with constant steady feed to the smelter and progressed to three mines producing eight products and a smelter varying feed inputs to maximise benefits. The initial optimisation was done manually using a desk top calculator and hand drawn graphs. This ultimately advanced to the use of PC plus linear programming software and spreadsheet generating relevant graphics. The financial benefits were achieved with no capital expenditure and increased from an initial $0.5 to $1.0 M/year (1973 $'s) to $5 to $10 M/year (1988 $'s).

Jan 1, 1991

This is a brief introduction of a sewer pipeline constructed with a pipe jacking method in combination with a 1 200 mm finished inner diameter tunnel boring machine developed for the first time in Japan. The pipeline is located under a national highway running through a densely built urban area and is 185.7 m long and 2.9 m to 3.7 m deep from the ground surface. The geological features along the pipeline show mostly slate and partly silt. The pipeline was constructed with a newly developed multi-application type tunnel boring machine equiped with a fluid transport system. The construction consisted of tunneling by a tunnel boring machine followed by pipe jacking operations. The excavated materials were dis- charged off the tunnel by a fluid transport System.

Jan 1, 1987

By I Grant

On the 1 June 1978, the Town and Country Planning Act 1953 was replaced by the revised and more comprehensive Town and Country Planning Act 1977. The new act brings in some substantial changes to the law affecting regional and district planning, and for the first time makes provision for maritime planning. The importance of the Town and Country Planning Act 1977 to the Mineral industry is primarily in the relationship between Regional Planning Schemes and District Schemes as the needs and resources identified in a Regional Planning Scheme will override the underlying District Schemes. The mineral extraction industry must be recognised as a regional responsibility which draws on the resources of a region to satisfy the demand of the communities within that region rather than a purely local operation within one District.

Jan 1, 1978

The four major contracts for the construction of Museum Station are: 1) Installation of Soldier Piles, 2) Structural Contract including the temporary support, 3) Architectural Finishes which include Electrical and Mechanical Services and 4) Supply and Installation of lifts and escalators. Specific areas of interest include the fabrication, installation and removal of temporary support steelwork, the monitoring of ground loading, and the interface between the structure and. the temporary support. The information collated during construction confirmed the design assumptions and criteria. No major changes'were required in the design of the construction methods. The open cut excavation and construction of this major structure in an inner city area was significant by any standard and was successfully completed with minimum disruption to the public and without damage to adjoining or surrounding property.

Jan 1, 1981

By Smith JW

Studies of 13C/12C ratios of carbon dioxide in seam gases and in secondary calcites show that 1. In mines prone to carbon dioxide outbursting, the source of this gas is external to the coal. 2. Faults draining reservoirs of magmatic or primary carbon dioxide, rather than intrusives, are the most likely points of entry of carbon dioxide into mines. 3. The higher the concentration of carbon dioxide in seam gas and the wetter the mine, the lower the likelihood of secondary calcite occurring as a filling in cleats, fractures etc. 4. A -role played by carbon dioxide in promoting outbursting may be the conversion of calcite to soluble bicarbonate, the removal of this in mine water and the subsequent weakening of the resistance of the bulk coal to stress.

Jan 1, 1980

The Amacan Copper Project was constructed in the Philippines by a Finnish-Filipino Consortium during the years 1979 - 1982. The project involved a turnkey contract for a mine and a concentrator to process 25 000 tonne per day of porphy- ritic copper ore at a grade of 0.45% Cu. The orebody is located on Mindanao, the southernmost island of the Philippines, in rugged, mountainous terrain approximately 1 000 m above sea level. The adopted design principle was based on an efficient, straightforward installation utilising a minimum number of items of equipment each with high unit capacities. The consortium faced many problems which resulted in lengthy delays in construction and finally led to the client taking over responsibility for the completion of the project. The concentrator was successfully commissioned in July 1982.

Jan 1, 1986