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The major copper orebody at Mount Isa is being extracted at a rate of four million tonnes per year. The method used requires an equivalent rate of back filling with (mainly) cemented fill. There were three major incentives for developing this mining system. The first was the prospect of high ultimate recovery of the orebody. The target is 100% recovery. Also the proposed stoping layout appeared to offer significant advantages in development and production costs. Finally, extensive subsidence above the northern end of the orebody could have disturbed permanent surface installations and jeopardised a possible future open cut. The full implications of this ambitious strategy were not apparent in the early years. Now, after twelve years of production the benefits are being realised and they can be weighed against the costs. Probably the most interesting result which comes from this analysis is the significance of cutoff grades and dilution factors in balancing mining and filling rates.

Jan 1, 1980

By Stewart WJ

Australia's first offshsore well was spudded in on 27th December 1964 and resulted in the discovery of the Barracouta gas field. Further exploratory drilling led to the discovery of the Marlin gas field in December 1965, the Kingfish oil field in April 1967 and the Hblibut oil field in June. 1967. In September 1968, a small oil reservoir was found in a sand below the main Barracouta'gas reservoir. The Snapper gas field was discovered in May, 1968 Information on exploration activities associated with the discovery of oil and gas in the Bass Strait area may be found in the paper, "Exploration in the Gippsland, Bass and Otway Basins, Australia" by B. M. Hopkins. _ Development of the commercial fields is being undertaken on an equal participation basis by Hematite Petroleum Pty. Ltd. and Esso Exploration and Production Australia Inc. Esso Standard Oil (Australia) Ltd. is responsible for the design, construction and operation of the production facilities.

Jan 1, 1970

An on-stream iron ore analyser has been developed in collaborationwith Hamersley Iron Pty. Limited for determining the iron content ofboth lump (- 30+ 6 mm particle size) and fines ( - 6 mm particle size)on conveyor belts. The analyser, which is called IRONSCAN, is basedon pair production, and is now commercially available from Mineral ControllnstrumentationLimited (MC!) in Adelaide. It can be mounted underexisting conveyor belts with minimal modifications to the conveyor structure,and the presence of steel cables in the belt does not interfere oncethe analyser has been correctly calibrated. The analyser has been extensivelytested on both lump and fines on the shiploading conveyor at Dampier,and typically the root mean square (Lm.s.) deviation between singleIRONSCAN measurements and conventional chemical analyses is betterthan 0.5070 Fe. It is currently being evaluated on - 150 mm ore from theprimary crusher at Mount Tom Price, and initial result are encouraging.The principal advantage of IRONSCAN is that it provides rapid informationon ore grades. But perhaps its greatest potential is at the primarycrusher where conventional sampling and analysis is very expensive toimplement.

Jan 1, 1988

By Smele J. S, Dawes W. D

In recent years there has been a trend among mining companies to diversify exploration and development away from the countries that have dominated mining activity for the latter half of this century. With some exceptions, this trend is accelerating and is a function of the recognition that many parts of the world, with no previous exposure to modern exploration, are endowed with considerable mineral potential. In addition coincident with changing political and economic circumstances, many countries have recognised the benefits of attracting international mining investment and have radically changed policies, fiscal and legal regimes so as to encourage exploration and mining. Some countries, however, have not readily accepted mining for cultural or social reasons and have yet to make effective changes to mining legislation. For historical reasons, other countries may have little or no direct experience of western economics, nor may they fully recognise the need for stability and competitive fiscal and legal systems to attract foreign investment. Not all ventures in new countries have been commercial successes and there have been some lamentable and recent lapses from grace. Company strategies, company standards and management objectives can also vary widely from company to company. What may be an acceptable risk or rate of return for one may be completely

Jan 1, 1997

Although developed primarily for sintering tantalum, the unit to be described can be used to heat-treat metals in the form ofa bar, wire or strip, by passing a current through them. The upper temperature limit with this type of heating is the melting point of the metal being heated.The unit was designed for vacuum work, but. various gases can be used if required.Briefly, the vacuum sintering furnace consists of a bell which is counter-balanced and may be lowered onto the brass base plate which holds the electrodes. A rubber ring seal is used for vacuum work. The lower flexible grips are bolted to the brass base plate which is at earth 'potential, while the other electrode passes through the plate by way of an electrically insulated vacuum seal. This upper electrode, the height of which can be altered as desired, the lower grips, and the bell are water cooled. The vacuum line to the pumps and a line to the vacuum gauges also lead from the base plate. The more important sections of the unit are described below.THE BELLThe unit was designed so that the bell could be lifted clear of the base plate and the electrodes, thus facilitating adjustment of the latter and the mounting of the specimen to be heated. A double walled steel bell, 20 in. high, with t in. cavity was used. The bell was fabricated from 10 gauge mild steel sheet using a double overlapping run of arc welding for all seams. A water inlet and outlet...

Jan 1, 1946

By Hyslop W

It is shown that coke has a major influence on the pattern of operation and on the aerodynamics of the blast furnace and that the physical and chemical characteristics of coke, at each stage in the furnace, determine its ability to satisfy requirements for iron production and coke economy. Analysis of coke sampled from operating furnaces is compared with furnace behaviour. The available data suggests the importance of segregation, strength, size change and chemical degradation of coke on furnace performance. Correlations are presented for coke breakdown ratio as a function of coke rate and hearth diameter which shows that breakdown increases with hearth diameter and with decreasing coke rate. It is also shown that the Micum tests do not reflect the coke strength in a predictable way and that solution reactions appear to play an important role in giving rise to a pitting effect on the cell walls of the coke with the resultant deterioration in coke properties. The catalytic effect of activating substances, such as alkalis, is noted and results are presented which show the effect of carbon solution on the coke strength. The importance of coke in the stack and in the bosh is discussed and flooding results are presented for BSC furnaces which show the probable driving limits for the furnaces considered. It is also shown that coke sampled from different tuyeres in a furnace gives quite different flooding limits. Other applications of the coke test work at BSC are also noted and the relevant objectives listed.

Jan 1, 1975

By Anylmore M, Walker A, Fletcher A

Roasting of sulphide and sulph-arsenide gold ores produces unwanted emission of sulphur and arsenic oxides, and a less than complete recovery of gold. Pyrite loses sulphur and arsenopyrite loses arsenic at a useful rate at temperatures of 600¦C and above in an inert atmosphere. Sulphur and arsenic driven off can be condensed before entering the atmosphere. During the process, solid-solution gold redistributes itself on internal surfaces of the resulting iron sulphide. Two subsequent processing options may be used; direct cyanidation of the porous sulphide resulting from the anoxic pyrolysis, or a second-stage roast to oxidise the remaining iron sulphide. The first option may be viable under certain conditions of pyrolysis. The two-stage option has an environmental advantage over the traditional roast because it reduces oxide vapour emissions by 50 per cent. The second stage may provide nearly enough energy to sustain the entire process.

Jan 1, 1992

By McDougall I, Claoue-Long J

A combination of high precision 40Ar/39Ar and U-Pb dating has been used to determine the age of hydrothermal minerals and host rocks in a number of Lachlan Fold Belt (LFB) gold deposits in New South Wales, Au4 ralii In particular, this investigation demonstrates that the UAr/ Ar technique of K-Ar dating can be used to determine the timing of mineralization in Palaeozoic systems.A close temporal link between mineralization and Late Ordovician to Early Silurian magmatism is indicated by the dating work. Hydrothermal sericite from the Goonumbla p8rph gy Cu deposit and Glendale Au prospect yieldsAt/ Ar step heating ages between 437.9 ¦ 1.1 and 441.2 ¦ 1.1 Ma (16), and4 minjrnum age of about 425 Ma has been obtained by Ar/ Ar dating of hydrothermal amphibole from the Browns Creek Au-Cu skarn deposit. Hydrothermal aluniI8 frog the Gidginbung epithermal Au deposit yields reset 44 Ar/ Ar ages of 401.0 ¦ 1.3 to 417.3 ¦ 1.3 Ma (16). U-Pb dating by ion microprobe on magmatic zircons from the vicinity of the Goonumbla and Gidginbung deposits gives ages of 438 ¦ 3.5 Ma (2 6), and 435 ¦ 2.5 Ma (2 (7) respectimly, W a minimum age of 435 Ma has been obtained by Ar/ Ar dating of magmatic phases from volcanic rocks adjacent to the Browns Creek skarn deposit. Magmatic episodes near the Sheahan-Grants gold skarnpost give ages of 479.2 ¦ 1.1 and 467.9 ¦ 4o1 by 'Ar/ 9Ar dating of magmatic amphibole. Most Ar/3yAr age spectra show the effects of partial Ar loss at between 360-420 Ma, probably due to heating caused by granitoid emplacement.The radiometric dating work in this paper suggests a restricted metallogenic epoch in the Late Ordovician-Early Silurian LFB, NSW, of similar duration to that found in the Andean margin and the western Pacific island arcs around the Pacific Rini.

Jan 1, 1990

By Frew J. A, Harris M. C, Manlapig E. V

The recovery achieved in a flotation process is a function of both the characteristics of the feed stream and the operating conditions within the flotation cell. In this paper, the flotation characteristics of the streams within the Red Dog le

Jan 1, 1997

By Lu T. K

A new type of rockbolting system, the self drilling rockbolt, has been studied to develop a 'single pass' bolt for use in rockbolt installation in underground engineering. This single pass bolt forms the basis of a Rapid Face Bolting system which will reduce the amount of time spent in securing a roof during the operation of a continuous miner in the development of a panel.The installation efficiency and anchorage tests were performed in the laboratory on the self drilling bolt and the traditional resin anchorage. bolt. The results of both bolts are cmmnared.

Jan 1, 1993

By Shrivastava P, Humphreys M, Guibal D, Deraisme J

Customer requirements concerning the final products of iron mines are extremely stringent. Because of this, there is an ever-increasing need for mine operators to monitor and strictly control the quality of their product. This quality, as measured by the stockpile grade variability, is the result of a very complex process, where natural characteristics (the orebody and its geology) are transformed through the mining technique (open pit, shovel and truck fleet, blending into stockpile). The only way to reproduce and hence to control the variability of such a system, which is composed of several interactive sub-processes, is by simulation. A complete simulation of a Hamersley Iron Pty Ltd (HI) ore deposit has been undertaken to forecast the impact and cost of various mining methods, mining schedules and product stockpile sizes on variability of chemical and physical characteristics of the products. The mining simulation was made on a conditionally simulated orebody. On a range of criteria, the simulation was considered to fulfil the objectives set and was a valuable aid to analysis of product grade variability, operating and capital costs, selection of equipment, mine scheduling and setting of product grade targets.

Jan 1, 1994

By Moore A. J, Evans R

Blast vibration control and assessment techniques have been developed which supplement traditional charge mass scaling methods. The improved techniques, which can be used to predict air and ground vibration levels at the planning stage, and to assist in the control of blasting operations, have reduced the level of operating risk concerning blast vibration. In addition to such factors as charge mass, distance and blast vibration levels, these additional techniques take account of orientation of the blasting face, topographic shielding, wavefront reinforcement, and meteorological conditions. They have assisted in compliance with specified blast vibration levels for environmental licence and mining lease conditions, the reduction of blast vibration nuisance to residents in the area surrounding a mine, and control of building and rock structure response in adjacent areas on the mine lease area.

Jan 1, 1994

The elements of consistent structural de sign models for underground structures are explained. Such models should comprise at least ground properties, excavation and support methods, computational models for analysis, failure hypotheses, and in-situ monitoring. The fundamental characteristics of the interaction between ground and support are investigated. Then, plane strain models for soft ground tun- nelling and design models for rock tunnelling employing stress release at the tunnel face are elaborated. Some numerical evaluations are gi- ven in diagrams, comparing approaches of dif- ferent authors. Comments are presented on nume- rical three-dimensional models (visualized by structural models for mining in rock salt), on the interaction of in-situ monitoring and design, on structural safety for underground structures, and finally on the general develop- ment of structural design models in geo- Techniques.

Jan 1, 1987

By Erickson M. E, Smith C. K, Carswell J. T

Thirteen holes totalling 3200m were surveyed using a downhole time domain Geonics EM37 system at the 830 metre level within the CSA Mine, Cobar, New South Wales, in order to search for blind, electrically conductive sulphides at some distance from exploration drillholes. A significant off-hole conductor was detected in only one drillhole.Geophysical modelling and interpretation of the survey results indicated that this off-hole conductor was caused by a sulphide lens 30 metres from the drillhole at a hole depth of 220 metres.

Jan 1, 1990

By Ghose AK

Design and selection of support systems for longwall faces call for in-depth know- ledge of strata mechanics and in particular of strata-support interactions. The paper presents the results of field investigations and analysis of a difficult-to-cave roof using powered supports under a massive dolerite sill in Central India using a state- of-the-art datalogger system. The mechanised long wall face was equipped with 4/680 tons chockshields operated on the IFS mode using a 300 KW DERD shearer. The datalogger system was capable of storing data simulta- neously in 32 channels. The paper describes the monitoring system and the monitoring programme. The system provided useful information on support behaviour, build- up of leg pressures and face convergence during an intense dynamic periodic weighting phenomenon which destroyed the integrity of almost half of the face supports. At this point, the face had advanced by about 197 metres from the barrier. The paper outlines a post-mortem analysis of this dynamic event and provides a critical evaluation of the data collected for understanding strata support interaction and the behaviour of the massive sill in the overburden.

Jan 1, 1992

By Restarick C. J & Stewart P S B, Kelsall D. P

Over a four-hour period of steady plant operation samples were taken at regular intervals from points within the grinding and flotation circuits. Size fractions of each composite sample were analysed for lead and zinc values and a comparison made of the behaviour of the lead, zinc and gangue minerals, size by size throughout the whole circuit. Analysis of the breakage behaviour using dynamic mathematical models gave the rates of breakage of each size fraction of each main component. Simulated grinding experiments showed that the main grinding circuit had sane reserve capacity. In the lead flotation circuit all lead values between 150 mesh (Tyler) and 5 microns had excellent flotation characteristics, and a major proportion had a high rate of flotation which was practically the same for all sizes. Increase in overall lead recovery would require improvement of the flotation behaviour of ultra-fine lead minerals. These were slow floating and were responsible for approximately half the lead losses in the final zinc concentrate and one third of the lead losses in the final tails.

Jan 1, 1980

By Mathew P. J

The CSIRO Division of Mineral and Process Engineering in Melbourne has been developing on-stream analysis sensors based on neutron and gamma radiation for better control of quality and process operations. This has resulted in the development of Ironscan, an on-stream analyser that measures the iron content of both lump and fine iron ore on conveyor belts. It can be mounted under existing conveyors with minimal modifications to the conveyor structure and can cope with steel cables in the belt. An interface gauge and an on-stream coal ash analyser have also been developed, both based on measurement of natural radioactivity. The interface gauge monitors the interface between liquor and mud in thickeners and washers, provided the natural radioactivity of the mud is sufficiently high to detect it above background. The natural-gamma ash gauge is a valuable addition to the Coalscan range of ash gauges. It is applicable to heavily laden coal conveyors or bins where the coal bed thickness exceeds 30 cm, and also to lightly laden conveyors, provided the coal is profiled on the conveyor.

Jan 1, 1991

By Soma T

Pyrite and Cu-concentrate were roasted in vertically suspended state in an externally heated tube. Tubes of three different lengths of reaction zone were used for three different reaction times. Roasted ores were submitted to chemical analysis and the extent of roasting reactions was determined. In case of pyrite, extent of roasting reactions was not affected much by reactor length and heating temperature (above 500¦C), but was considerably by ore/air ratio. Micro- scopic and XMA examinations led to the conclus- ion that pyrite particles decomposed to pyrrho- tite and then pyrrhotite was oxidized to give Fe-S-0 melt, magnetite and hematite. The extent of reaction was not uniform in all particles but had a wide distribution from unreacted pyrite to completely oxidized particles. Combustion of Cu-concentrate from Kuroko complex sulfide ore ) was unstable under a uniform wall temperature of 450¦C, but proceed- ed rapidly at temperatures above 500¦C. Sticking of roasted ores to the wall of the reaction tube induced choking of the tube, caused by melting of roasted ores, at tempera- tures above 950¦C. Enrichment of oxygen exterted less influence on reaction rate than heating temperature of the tube. Particle size of ore had a big effect on reaction rate.

Jan 1, 1980

By Campbell R

The use of a 35mm non-metric SLR camera and an analytical plotter to prepare close range photogrammetric (CRP) plans of a quarry and open pit mine face is described. The plans, at scales ranging from 1:5 -1:1 000, were used to measure the orientation of geological structures and failure surfaces in the exposed faces.Details are provided on the equipment used and the field techniques. The method:ò is quick and relatively cheap to perform,ò allows the accurate orientation of specific geological features to be determined,ò provides survey results of suitable accuracy that may be used for detailed geotechnical analyses of pit wall failures,ò shows great potential as a rapid and accurate technique for monitoring changes in pit wall profiles with time.

Jan 1, 1990

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