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By Braaksma M, Dudley K

The Girilambone Copper Mine is located in central New South Wales and has been operational since May 1993. Girilambone is operated by the Girilambone Copper Company (GCC) which is a joint venture between Straits Resources (60 per cent) and Nord Resources (40 per cent). The mine complex consists of an open cut pit, ore crushing and stacking, heap leaching, solvent extraction (SX) and electrowinning (EW) allowing for the recovery of 14 600 tpa of LME grade A cathode copper. The leaching and SX-EW plant have been described previously by Rear, Taylor and Busby (1994) and Miller (1994).

Jan 1, 1996

By B Arthur, K Sexsmith, D Hockley, S D

At the proposed Crandon Project, mill tailings would be depyritised for upland disposal. The resulting pyrite concentrate would be disposed of in the underground workings as a cement-amended paste backfill. In the long term, the underground workings would be flooded and the potential for the paste backfill to generate acid would be limited. However, while the mine is operational, there is potential for oxygen ingress to the backfill that may lead to sulfide mineral oxidation and acid generation. A series of humidity cell tests were completed to assess the potential for groundwater contamination. To assess effects of surface area on oxidation, the humidity cell tests were conducted on moulded cubes of paste backfill. The tests were terminated at different intervals, and the cubes were dissected and examined mineralogically. Various leach extraction procedures were also used to assess the progress of oxidation and secondary mineralisation within the paste backfill. The test results showed that: the cement amendment significantly contributes to acid neutralisation and results in a lag in excess of one year before the onset of acidic conditions (in comparison to less than three weeks for the pyrite concentrate); the depth of oxidation in the paste backfill is restricted to about 1 mm after 107 weeks of testing; and secondary minerals form a distinct ærindÆ at the surface of the paste backfill. The results indicate that acid generation in the backfilled stopes would be minimal. The importance of including the surface area effect in the testing (ie using moulded cubes) is clearly demonstrated.

Jan 1, 2003

Kambalda Nickel Mines (KNM) currently have eight operating underground mines, three on care and maintenance and other orebodies at various stages of development. Each operation differs greatly in scale, ore grade, milling characteristics and cost structure. The optimum number of mines operating at any one time and their level of production, within the constraints of mill blending requirements and overall mill capacity, is the key to maximising profit in a climate of fluctuating nickel price. Cost models are developed for each mining operation which relate ore tonnes mined to total cost per pound of nickel produced from that mine. Aggregating the mine cost models provides a composite cost model for the entire operation. The cost models provide the operating levels necessary for each of the mines and hence Kambalda as a whole, to operate at the lowest cost per pound of nickel produced. However, lowest operating cost does not necessarily lead to maximum profit. The level of nickel price above operating cost can dictate maximum profit positions which are contrary to the lowest cost position. In addition, the decision to temporarily shutdown mines or reopen mines in response to nickel price movements comes at a cost. In considering the optimum operating position, the price of production capacity flexibility needs to be taken into account. This paper describes the process used to assess all these factors in arriving at the optimum operating position for Kambalda Nickel Mines for varying nickel prices. The same methodology can be used by corporate management in managing multiple mine sites as well as mine management managing multiple orebodies or stoping blocks for maximum profit.

Jan 1, 1995

By Lawson F

A rotating disc geometry has been used to provide a uniformly accessible surface for a kinetic study of the cementation of the metals cadmium, lead and silver from dilute aqueous solutions. This work is an extension of studies carried out on the Cu/Zn and Cu/Fe systems for which the rection rate was found to be completely solution-phase mass-transfer controlled. When the amount of material deposited was greater than 0.2 to 0.4 mg/cm2 there was an apparent enhancement in e which is attributed to the formation of a roughened deposit. This same phenomeon was obseived in the Cu/Zn Cu/Fe systems. Again, the rate of reaction of each system investigated was found to be solution-phase mass ,..~sfer controlled.

Jan 1, 1970

By Baczynski NR, Fagan MJ

A 3050m long section of a 1.65m internal diameter tunnel is presently under construction in the Brisbane area by means of the pipe-jacking method. The soils along the alignment had been deposited in a deltaic/estaurine environment and rapid changes in soil type occur. The tunnel passes beneath several extensive bodies of surface water. Groundwater problems have been experienced with tunnelling through alluvial sands and gravels. Details of the ground conditions, the pipe-jacking method used and tunnelling experience are discussed in this Paper.

Jan 1, 1987

By Hannington MD

On the southern flank of Lihir Island, a group of three volcanic cones were discovered at water depths from 1000-1500 m. The volcanoes are located in a narrow zone of recent seismic activity and elevated heat flow (up to 100 mW/m2). The recovered rocks consist of fresh alkali-olivine basalts, clinopyroxene-rich basalts, and porphyritic phlogopite basalts. One of the volcanoes has a recently erupted ejecta blanket (recovery of warm ash!), containing a suite of abundant mafic to ultramafic xenoliths. These xenoliths appear to represent a unique cross-section of subduction- modified mantle material sampled by volatile-rich primary fore-arc magma during its ascent to the seafloor. The most spectacular finding was the discovery of an active hydrothermal system with associated vent fauna and mineralization at Edison Seamount, and the recovery of unusually gold-rich (up to 43 ppm Au) hydrothermal precipitates in 1050 m water depth at the top of Conical Seamount, only 25 km south of the world-class epithermal Ladolam gold deposit on Lihir. The discovery of submarine hydrothermal vents associated with highly alkaline, quartz-undersaturated fore-arc volcanics represents a significant departure from similar hydrothermal systems on the mid-ocean ridges and in back-arc basins. The high gold grades in hydrothermal precipitates at Conical Seamount may indicate the first documented example of a shallow-marine epithermal system analogous to those known on land, and has important implications for the gold potential of submarine arc environments.

Jan 1, 1995

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

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

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

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