Search Documents

Exploration for uranium in Australia commenced only during the 1940s, but in this short period has been very successful as one third of the world's low cost uranium reserves have been discovered in Australia. Total uranium exploration expenditure in Australia up to the end of 1983 was $A(1983) 554 million; this discovered 20 potentially economic deposits and official reserves of 560 000 tonnes of uranium oxide at an average cost of $1 per kg of U 0 . An exponential 8 eserves indicates distribution of uranium r that there could be 54 undiscovered uranium deposits in Australia, each with reserves of 20 000 tonnes U308 or more, in addition to smaller deposits. Using a constant uranium price of $A(1983) 79 per kg, no deposit is economic at a grade below 0.12 per cent U 08 or with reserves of less than 3 000 tonnes. Selecting deposits with reserves of 5 000 tonnes U 0g or more as prime exploration targets, only 39 per cent of discoveries will yield a real internal rate of return (IRR) of 10 per cent or more. After committing a minimum exploration budget of $10 million to this search, an explorer has one chance between 7 and 12 of discovering a deposit that will repay the exploration investment.

Jan 1, 1984

I am very pleased to be here at this seminar on carbon-in-pulp (CIP) technology for the extraction of gold as I am always interested to hear about any new development in any aspect of gold ore processing. We can expect to learn a great deal from the papers to be presented over the next few days. It is not my purpose to give a detailed description of the CIP process nor to give a complete historical review. However, in this opening address it was thought appropriate that I should mention some historical features and some technical factors to set the scene for subsequent papers. HISTORICAL NOTE Table 1 shows some interesting dates of the use of carbon in gold metallurgy in Australia. Mount Morgan used carbon after chlorination TABLE I Carbon precipitation in Australia 1891 Mount Morgan 1917 Yuanmi mine (Edmunds) 1934 Sons of Gwalia (Edquist) 1975-1980 Various pilot plants and small companies 1980- Various large and small plants

Jan 1, 1982

The Blackwater Coal Mine is a modern open cut operation using large draglines for over- :)urden removal and shovels, loaders and trucks to mine and haul coal to the crushing and coal ?reparation plant. Operations at the mine are described in sequence following through overburden removal to the railing of product coal from the mine site. The close operating connection between the mine and washery, which results from the blending of raw coal into clean product via the qashplant bypass system, is stressed. Some features of special interest at Blackwater Mine, such as land reclamation and slope stability,are outlined.

Jan 1, 1974

Our ultimate resources come from the Sun and the Earth System. At this time we face a world crisis in energy, water and soil resources. Global pollution problems are increasing in almost all nations. There is an urgent need to use our vast knowledge with a new wisdom and this requires new integrated teams of experts to provide the best alternatives for the needed new development problems. These teams must include economists, engineers and a broad spectrum of scientists. Today it is possible to produce clean energy, stop soil erosion, clean water and reduce and use wastes of many types.

Jan 1, 1995

By McMahon DW, Schapper MA

Hard rock underground mining has been wedded to the drill-blast method of breaking rock. Current practice and technology have focused on greater efficiencies in the blasting and handling of ore, on the basis that thelower costs that come with larger scale operations compensate for the waste dilution associated with the bulk methods. However, it is suggested that new technology is available or is on the horizon that could completely change the shape of hard rock mining in the 21st century. Hard-rock continuous-mining machines, possibly assisted by high pressure water jets, coupled with automated sorting and materials handling systems, could re-orient the miner's focus to winning metal rather than mining tonnes of ore. More continuous mining processes could accelerate the penetration by high technology in the hard rock underground mine, with the potential of greater manpower productivities and lower costs per tonne of metal produced. This new technology will be important in maintaining a competitive supply of metals, given the falling headgrades of the orebodies remaining for development and the increasing market threat from manufactured substitutes.

Jan 1, 1985

General design of pillars to ensure a continuing roof support during ex- traction is discussed. Practical problems associated with pillar extraction are Outlined.

Jan 1, 1974

By J McQuie

The concentrator at WMCÆs Leinster Nickel Operation has operated with flash flotation in the grinding circuit since the early 1990s. There has always been a positive correlation between flash flotation Ni recovery and overall Ni recovery û however this relationship could be explained by differences in the ore, rather than by the action of the Flash flotation cell in reducing overgrinding of Ni. In July 2003, refurbishment within the plant made it necessary to operate the concentrator for a period with the flash flotation cells off. The resulting data set provided evidence that flash flotation in the grinding circuit changes the size distribution of Ni to reduce the amount of slow-floating fine (-7 ¦m) Ni produced. Ni recoveries in the finer size fractions were similar with flash flotation on or off û but because less fine Ni is produced when the flash flotation cells are operated, overall Ni recovery improved.

Jan 1, 2005

By Johnston RRM

There have been many published mathematical models that, to varying degrees of sophistication, attempt to describe dynamic thickener behaviour. CSIRO has undertaken to develop a model under industry sponsorship. Recently developed instruments such as the floc density analyser and natural gamma-ray gauge have enabled new data to be collected from plant thickeners for model validation and development. The principles behind the use of the natural gamma-ray gauge are described and the possibilities for its use as a control instrument in the bed have been examined. A simple nomograph illustrates how the gamma-ray gauge data can be used to predict steady state underflow consistency and bed Position.

Jan 1, 1991

By Nilsson C

Man has always been and will always be part of his environment, in ,a good, bad or indifferent manner. Until quite recently, this environment has been the atmospheric boundary layer above the land masses, and to a limited extent the air-sea interface of the oceans. Since the days when he lived in caves, he has built up a wealth of observations on these two environments,-with ever-increasing scientific precision which unfortunately until quite recently was completely insufficient for modern capabilities of data analysis. Consequently, in a sense, he has left in his wake thousands of years of missed, opportunities for making exact observations and increasing his understanding. The data of the past are lost and he has to be satisfied with what he can assemble from now on when his environ- ment, largely as a result of his actions, is exhibiting more and more rapid variations in time; in other words, time series of observations of phenomena are required, the length of which is critical for most purposes of analysis.

Jan 1, 1970

As a result of the rapid economic growth in Japan, environmental problems have become a national concern in the latter half of the In 1967, the Basic Lair for Environmental Pollution Control was enacted as a fundamental ::olicy in this field. This lair provided compre- hensive guidelines for the action to be taken pollution prevention. The biggest problem n air pollution of those days was that of the sulphur dioxide content of the atmosphere. Based upon the law, the smelters in Japan have struggled hard to solve this difficult problem. Consequently, the ambient SO2 level has been lowered gradually year by year. At present, the ambient SO2 level is nearly equal to that in the atmospheric background. Furthermore, the fixation ratio of sulphur in Japanese copper smelters has attained up to 99.5 per cent.

Jan 1, 1980

By Abishev D. N, Balakirev V. F, Davydov G. I

The problem of recovery of cobalt products from poorly oxidised nickel ores (Kempirsaisk deposit) and pyrite concentrates with a low content of cobalt (Sokolovsk-Sarbaisky deposit) has not been solved to the present time in Kazakstan. The balance reserves of nickel ore of the Kempirsaisky deposit make up more than 35 million tons with a nickel content of 1.13 per cent and cobalt content of 0.05 per cent; besides there are 110 millions tons of out-balance ores (Anon, 1995). In a tailing dump of Sokolovsk-Sarbaisk Mining and Productional Association more than 320 million tons of tailings of wet magnetic separation have accumulated, which contain 7.2 per cent of sulphur, 0.022 per cent of cobalt, 0.012 per cent of nickel, 0.094 per cent of copper, 0.079 per cent of zinc, 16.45 per cent of iron, and from which a high quality pyrite concentrate car) he separated through flotation, containing 48 - 50 per cent of sulphur, 44.15 per cent of iron, 0.141 per cent of cobalt, 0.07 per cent of nickel, and 0.10 per cent of copper. The well-known technological flow charts for cobalt and nickel recovery from the tailings of sulphide-magnetite ores dressing (to give pyrite concentrate) and from oxidised nickel ores, are not profitable at the existing prices for metals, but are not worthless and require significant capital investments for the realisation of their value. The flow chart `sulphate roasting - leaching - solution processing' is used widely for combined processing of cobalt-containing pyrite ores and concentrates.

Jan 1, 1996

By Hammond J. R, Ward T. A

The Tom Price orebody, in the Hamersley Ranges of North West of Western Australia, is mined by Hamersley Iron Pty. Limited. The orebody is a folded sequence of hematite and shale bands capped with goethite, with a con- sequential variable iron content. The overall grade is below that required to yield spec- ification product, necessitating selective mining, 'Zone Plans' based on geological structure have been developed to yield forward information on material types and grades. Short and medium term mine plans - the initial stage of quality control - are based upon these 'zone plans'. Blasts are laid out to break to the grade boundaries, thus minimising dilution, and the samples taken from the blasthole cuttings provide blast grades. Blending of shovel out- put from different blasts forms the operational basis of grade control. Shales, being more friable than hematite, produce fines that are lower in iron grade than lump. Quality control in the mine centres around maintaining the target fines grade, compensation being applied in the mine if the fines grade lies outside the target range.

Jan 1, 1973

It is very apparent that the hydrogeotogicat characteristics of mineral deposits in China be dominated by meteoric factors, terrain factors and the kind of karstic aquifers as a main source threatening the mining.The hydrogeotogicat characteristics of mineral deposits in dry areas are very different from that in non-dry areas.The rote of precipitation is very important to mine dewatering.The difference of water recharge condition of a mineral deposit located upper (or under) Local erosion basis is existing. There are more than two million square kilometers of carbonate in China.Many water-bearing deposits are distributed in it.According to the karst shapes the surrounding karstic aquifers of mines can be divided into three kinds including solution fissure aquifer,karstic cave aquifer and underground stream (karst stream) aquifer. Underlier invasion is a main feature of karst water-bearing coal mine and upper tier incoming is a main feature of skarn copper and ferro mine.Swatlor pillar and collapse is a special feature of karstic water-impregnated mine.

Jan 1, 1988

As partition curves are widely employed to characterize screening efficiency which, by definition, should include a time parameter, it is shown, perhaps for the first time, that time is already included in the partition curves and how. Laboratory and plant results are used to show how screening efficiency depends on feed composition, near-mesh and oversize material and screen motion, and how these factors may combine to give an erroneous result that two identically efficient screens are different and two screens of different efficiency are identical. Reasons are given which show why a renewed interest in screening would benefit not only screen engineers and operators but also those concerned in formulating standard specifications of screen analysis methods.

Jan 1, 1984

Evolutionary changes to the original sizer concept are mild when compared to those which have taken place in the engineering standards embodied in today's commercially available machines. This paper examines the principles of sizer operation and reviews the development trends in new applications for this unique screen type.

Jan 1, 1978

By Denby B, Hollands R. Schofield D

Surface mines are in operation worldwide, the vast majority employ large haul trucks for the transfer of material both to the outside world and around the site. The sheer size of these trucks and the operating conditions means there is a high

Jan 1, 1998

By Szwedzicki T

Uniaxial testing was performed on model pillars to determine the effect of width to height ratio on pillar and surrounding rock mass stability. Samples were modelled in a shape similar to that of dumbbell weights, with the centre representing

Jan 1, 1994

By Rogers M, Sullivan B

Golden Crown Mine is a narrow vein gold mine producing 75000 tpa. Production has been predominantly by shrink stoping using hand held machine and airleg. Bogging from these stopes is done with Toro 150 LHD units.Previously the standard development method consisted of developing a sill drive, a footwall drive and millholes every 7 m. This meant that for every metre of ore development, 2 m of waste development was required.

Jan 1, 1993

Structural analyses of oriented bore core sections from the West Wallsend No.2 Colliery Holding together with investigations in adjac- ent collieries and on the surface delineated structural phenomena. The rocks examined are anisotropic due to strongly developed bedding planes and the presence of penetrative joint planes. Joints, in this context, are regarded as mechanical discontinuities, they are genetically identif- ied wherever possible and their spatial attit- udes are determined and geometrically related to the regional structure. Identifiable anisotropies in the roof- and floor-strata of the Borehole Seam render favour- able mining directions for longwall and bord and pillar layouts.

Jan 1, 1972

By Armstrong AB

It has been identified that particulate matter in the form of suspended solids and bed load has the ability to adsorb heavy metals. Each year Ranger Uranium Mines Pty Ltd (RUM) identifies potential danger areas which could become major sediment sources during the wet season. Methods of suppressing sediment uptake such as hydromulching and coating areas with Poly Vinyl Acetate (PVA) glue are used. Other methods of reducing the sediment load after uptake such as diversion bunds, filters across drains, stone filters, minor sumps and settling ponds are also used. The 1983/84 wet season saw drain sediment loads reduced to acceptable levels before the water reached the outside environment. Studies to qualify and quantify flows from minor drains are still underway.

Jan 1, 1984