Search Documents

In May 1977 a new dam was commissioned for disposal of 600,000 metric tonnes/year of tailings. Design basis, costs and construction problems are described. Problems arose, assoc- iated with lack of experience in building such a dam "from scratch". Solutions are described land costs given.

Jan 1, 1978

Towards Improved Hydrocyclone Models - Contributions from Computational Fluid Dynamics

Sep 13, 2010

TasmaniaÆs mineral endowment has resulted in 600 abandoned mines. Commonly occurring sulfide minerals such as pyrite and pyrrhotite can generate acid drainage and also mobilise heavy metals. Due to the StateÆs steep topography and high rainfall the risk to water quality in the receiving environments is significant. Surface waters impacted by abandoned mine sites typically showed high sulfate and metal distribution at pH range of 2.0 to 5.0. The impacted waters generally showed metal distribution in the high acid/extreme metal to low acid/low metal range. A similar trend was shown by sulfate distribution. Elevated levels of metals and sulfate downstream from several abandoned mine sites indicated that active sulfide oxidation is occurring and these sites may be potential point sources of metal pollution in the receiving environment. High correlation between metal and sulfate distribution suggests that sulfate distribution in surface waters may be used as a cost-effective investigation tool for preliminary assessment of acid drainage.

Jan 1, 2003

Many volcanoes in western Melanesia have tectonic settings and rock compositions that do not conform to conventional models of arc- trench systems. Part of the reason for this may be that in an environment of rapid tectonic change mantle source regions bear the imprint of former subduction even though subduction has now ceased. Results bearing on this concept and on other important aspects of Plelit nesian v ican ism and tectonics, were obtained in 1982-1986 from >e,:eral marine - geoscience studies in the re,,ii n

Jan 1, 1987

By Newell R

The influence of layering on the rate of heat transfer through a packed bed consisting of particles of two different sizes and heat capacities has been determined by measuring the heat front velocity through beds of quartzite particles and iron ore pellets. The heat front velocity through the layered beds was less than that through a bed consisting of a random mixture of the par- ticles. This is due to the formation of an interface in which the smaller pellets in one layer penetrate into the layer of quartzite Below.

Jan 1, 1987

Mine evaluation methodologies are well suited to evaluating many projects in capital-intensive industries other than mining. These industries include oil, gas, power generation, transport and infrastructure projects. A case study of an open cu

Jan 1, 1998

This paper outlines the thermodynamic and mass balance principles which affect the distribution of cobalt between matte and slag during the pyrometallurgical treatment of nickel - copper sulphides and considers the implications with regard to maximising the recovery of cobalt from the smelting and converting circuit.

Jan 1, 1992

By Campbell J

After eighteen months of discussions with employees and their trade unions, multiskilling was introduced at the Hellyer concentrator in early 1989, coinciding with the plant commissioning. Multiskilling was introduced with the Hellyer Skills Acquisition Program together with intensive training and performance assessment. Design innovations have helped to improve productivity. There have been some difficult times with personnel tending to return to the old and traditional ways of operating. In general, these have been overcome to ensure the success of multiskilling at Hellyer. The main factors making multiskilling effective have been continual training and assessment, and a competent team of shift supervisors. This has improved work standards towards the high level expected from a multiskilled approach without compromising safety standards.

Jan 1, 1991

By Weller KR, Restarick CJ, Stewart PSB

Following a detailed assessment of concen trator performance at Broken Hill South Limited which was reported in a previous paper, the fine grinding section was changed from a parallel arrangement of the two grinding circuits to a series arrangement, and the concentrator per- formance re-assessed. The change to series grinding had virtually no effect on the actual or potential capacity of the circuit to make a final product with 80% passing 100 mesh. However, the fresh flotation feed contained significantly less +150 mesh lead and +65 mesh zinc (material which was shown to float poorly), without an increase in the quantity of poor-floating ultra-fine lead and zinc. From the size-by-size flotation recovery data, it was shown that overall recoveries of both lead and zinc were approximately 1% higher than they would have been without this change in size distribution and it was concluded that this was a direct result of the change in grind- ing procedure.

Jan 1, 1972

By Hanes J

More than 200 bursts in coal occurred at Leichhardt Colliery prior to December 1978 during mine development in the 6 m thick Gemini seam at depths approximating 400 m. Three large bursts each displaced more than 300 tonnes of coal and stone. Two of these which occurred in continuous miner developments, are described and compared. Geological settings, mining strains including induced cleavage and roof failures associated with bursts are described. A shotfiring technique replaced mechanised mining following a major incident at the colliery. Present mining procedures, the apparent improvement in stability of workings and ongoing geotechnical monitoring programme are discussed.

Jan 1, 1980

By Lyman GJ, Davis JJ

Models which have been presented in the literature consider only selected aspects of dense medium cyclone operation, are empirical in nature and generally relate only to severely limited ranges of operating parameters. This paper reports progress towards development of a more comprehensive and robust model. The data base consists of partitioning parameters developed using density tracers and conventional coal sampling and analysis techniques, together with recordings of parameters such as cyclone dimensions, feed pressure, medium size distribution and product media densities.. These data were drawn from 15 Australian coal preparation plants. To elucidate the effects of important operating parameters on medium behaviour and on the partitioning of large particles a series of pilot scale tests was also conducted. The present model consists of eight sub-models which relate to particular aspects of dense medium cyclone operation such as medium flowrates and densities, or size- by-size separation densities and Eps. The model structure follows a logical progression which clearly demonstrates the importance of understanding medium behaviour before attempting to predict partitioning performance. The model also attempts to define the conditions under which yield losses due to unstable "surging" discharge may occur.

Jan 1, 1987

Australia has been an important producer of zinc minerals and metal for many years.Late in the last century Edgar A. Ashcroft, a versatile and enterprising electrical engineer proposed the treatment of zinc rich ores by roasting, followed by leaching to extract zinc, purification of the solution and electrolysis of the purified solution to produce zinc. Residues from the leaching operation were to be smelted in a lead blast furnace to recover lead, silver and gold.Ashcroft (1897-98) and (1898) has.given us a most interesting record of the attempts made at the Sulphide Corporation's plant at Cockle Creek near Newcastle, NSW, to put his ideas into practice. In spite of the best efforts of all concerned, including the use of electrolysis of aqueous chlorides and sulphates, zinc could not be deposited consistently and the project failed although lead smelting continued until 1922 (Woodward, 1965, p. 158). Based on later experience with Broken Hill materials the presence of undetected cobalt in the solutions was the likely cause of the inability to deposit zinc (Kirk and Othmer, 1956).

Jan 1, 1985

Obtaining correct assays for gold determinations relies on the correct methods being chosen and the assayer being made aware of the mineralogy of the sample and its general origin. Usually when a geologist or metallurgist obtains "incorrect" gold assays the problem can be traced to poor communication between the geologist or metallurgist and the assayer.

Jan 1, 1986

By Enever JR

In-situ rock stress measurements conducted in the Phillipines and on Bougainville have revealed stress fields significantly different from expectations based on intraplate experience. The results have potential significance in regard to both engineering practice in the Pacific Rim region as well as in helping to understand the geological processes occuring near subduction Zones.

Jan 1, 1987

By Quast K. B

Samples of limestone and micaceous hematite have been ground in a laboratory batch mill using equal weights of either rods or balls. Values of the Schuhmann distribution modulus, a, have been shown to depend on grind time and do not remain constant as often reported. The linear reduction in a with grind time was attributed to a change in grinding mechanisms with time. The product sizing from ball milling limestone showed a bimodal distribution, but rod milling produced a unimodal size distribution. The product sizing from milling micaceous hematite was difficult to interpret due to the major influence of the shape factor on the transition from screen sizing to cyclosizing.

Jan 1, 1995

Coal geology plays an essential role in the investigation of in situ coal seam quality. Coal geology can also play an important part in laboratory studies such as coal washing and coking, and in operating plant problems.

Jan 1, 1976

By Harvey T, Kizil M, Bride J

Hydrogen sulphide (H2S) as a seam gas has occurred in several locations in the German Creek seam at Southern Colliery. This paper overviews the techniques developed to quantify the H2S content of the seam, overviews research into controlling and reducing H2S emissions from the seam, and details the procedures used to mine through the HZS zone in 702 longwall panel. Learning points from research and mining experience are reviewed for application in the next longwall block.

Jan 1, 1998

By Restarick C, Jowett A

A cylinder-cyclone system, fitted with a flow control valve between the cylinder and cyclone plus in some tests a variable cyclone spigot, has been used to achieve classifier separations at unusually coarse sizes relative to the diameter of the units used. The method has proved to be useful for low tonnage flows at low pulp density and variable feed rate. The system relies on use of a cylinder unit to reject excess water and fine particles, the amount rejected being adjusted by the flow control valve. The valve also adjusts flow rate and pulp density of feed to the cyclone unit, and can be adjusted to give a separation at a coarse particle size. The system has been used in connection with experiments on the pilot plant at Mount Isa, where a 76 mm system was used to classify feed to the lead secondary rougher circuit at sizes as coarse as 52 micrametres galena equivalent for split conditioning tests. Further tests have been carried out with quartz to assess the range of size separations Possible.

Jan 1, 1978

By Yinxiang W, Chunlai Y

In older to improve efficiency of surface pre--grouting in sealing off water in heavily water-bearing strata, such as sandstone,siltstone and limestone, several methods have been used in China, they are ; intermittent pre-grouting, adjusting pre-grouting parameters and stepwise repeated pre-grouting methods. The paper describes effect of deviation on water sealing in pre-grouting. Deviation correction measures, like mechanical, technological and changing hole position methods have been introduced with satisfactory results in practical engineering projects without increasing the volume of engineering project and without causing delay.

Jan 1, 1988

By LaBrooy SR

A number of gold processing plants in Western Australia have nickel in their ores, leading to significant levels of nickel on their loaded carbon. The presence of nickel during leaching, adsorption and elution'may have detrimental effects on cyanide consumption, carbon inventory requirements, stripping costs, electrowinning efficiencies and may contaminate the gold bullion.This paper discusses the competitive adsorption of gold and nickel cyanides onto activated carbon and investigates changes in solution parameters that may improve gold adsorption and/or inhibit nickel adsorotion.

Jan 1, 1997