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By K McCaffery, R P. Halomoan

Two column flotation cells have been installed as single-stage rougher cleaners at Batu Hijau. The objective was to provide additional residence time in the cleaner circuit to maintain maximum recovery during high mill throughput and high feed grade periods. Installation of the columns has allowed the relatively coarse, well-liberated rougher concentrate and the relatively fine, low-grade scavenger concentrate to be treated separately, improving metallurgical performance in the cleaner circuit. Plant results show that the columns produce a high-grade concentrate at an average stage copper recovery of approximately 80 per cent. There is also indication of increases in both overall plant copper recovery and final concentrate copper grade. In addition, the operability and stability of the cleaner circuit has greatly improved.

Jan 1, 2007

Seven papers have been reviewed and in this session. Broadly they can be grouped into three categories as follows: A Chemical Characterisation of Mine Waters Miller & Murray - Prediction of Time Dependent Factors in Acid Mine Drainage Jeffrey et. al. - Sulphide Oxidation in Pyritic Overburden; A Controlled Leach Column Study Sheridan et. al. - The Effect of Ore Type, Depth, and Leach Time on Cyanide Species in Column Tests using NaCN Leach Solutions B Mine Water Treatment Management Gilchrist & Hunt - The Recovery of Water from a Colloidally Stable Kimberlite Suspension Chapman, et. al. - Treatment and Utilisation of Hilton Mine Water

Jan 1, 1988

The attachment of a spherical particle to a bubble is theoretically investigated under the condition of a mixed sorption coating of a collector. It is shown that the attachment is determined primarily by the hydrodynamic factor involving the displacement of liquid from the gap between a bubble and a particle. The dependence of the attachment on the state of the surface of particle (sorption coating) is due to a change in the boundary conditions on the interface with water both in the case of surfactant chemical sorption and in that of the physical adsorption of oil. It is demonstrated that at large distances the thinning of a interlayer is facilitated by a physically sorbed collector, while near the bubble this is done by a chemically sorbed one.

Jan 1, 1993

By Lynch A. J

The success of the Australian mining industry depends on the quality of its skills. High quality skills supported by a culture which demands success lead to innovations, good practices and prosperity. Average skills lead inevitably to mediocrity. Universities play an essential role in the development and use of skills but the crucial industry-university links have been subordinated to conventional academic interests in training mining and processing engineers. It is only in the area of post-graduate research degrees which are oriented towards the mineral industry that Australia can claim world leadership. Deficiencies are not due to lack of training resources, they are due to inadequate utilisation of the resources that are available. Australia can and should have the world's best mineral engineering school, with a branch in Asia where many of its customers are and close ties with South America where some of its production operations will be. Some steps which might be taken to achieve this are proposed.

Jan 1, 1995

By Sudharto RT

Sulphides of Cu, Pb, and Zn occur in quartz veins associated with a quartz monzodiorite stock at Gunung Limbung, West Java. The mineralization was polyphase and occurred at depths of less than lkm. Wall- rock alteration is extensive and typically consists of an outer zone of propylitization and an inner zone of potassic (K-feldspar- rich) alteration. Sporadic argillic altera- tion is probably of supergene origin. A variety of elements were mobilised during hydrothermal alteration and Ba in particular shows mared enrichments in the potassic zone. Fluid inclusions in the vein quartz indicate that temperatures of mineralization were within the range 250-3900C and that two fluids with differing chemistry were involved. One fluid had high Ca/Na ratios and a low overall salinity, the other had low Ca/Na ratios and a moderate salinity. The former is probably of meteoric derivation, whilst the latter had a magmatic origin. Precipitation of the sulphides was probably brought about by mixing of these fluids.

Jan 1, 1987

The concept of "profit" is implicit in the definition of an ore reserve. It is suggested that the flexible concept "economic" is more appropriate. This allows different economic considerations to be taken to account when determining what is ore at the feasibility study stage; during actual mining production; before mine closure; and from the viewpoint of the national economy. Economic factors which are highly variable, and largely beyond a mining enterprise's control, affect the economic exploitation of a mineral resource. Major economic factors include: metal prices; operating costs; the cost of original and replacement capital equipment; the cost of capital; taxation and royalties; inflation; exchange rates and the state of the world economy. The paper suggests why a careful quantification of the average value, trend, and variation from the trend of major economic factors should be made and how this will lead to a better definition of ore reserves. The paper also discusses the necessity of reappraising economic factors during the life of a mine in order to maximise the economic surplus and to minimise the wastage of natural, economic and human resources employed in mining.

Jan 1, 1979

By Ruffles B. R

A computer simulation has been developed to model the flow of copper ore in Isa Mine. It simulates extraction of copper ore from the 1100 orebody by load-haul-dump (LHD) units to ore passes, haulage from chutes on 19 level by Rockflo trains to crusher bins, crushing and hoisting. It can assess in terms of the tonnage and head grade of ore hoisted, the effect of varying operating strategies, as well as measur- ing shortfalls in required capacities of any of the operations (extraction, hauling, crushing and hoisting). The simulation was designed as a modular, deterministic, steady-state model with parameter input allowing complete flexibility in its use. Queuing theory is used extensively to evaluate the effect of interference at potential bottlenecks. The model has been used to determine the effect on production of varying train sizes, maintenance policies on the haulage circuit, orepass capacities, and extraction operations.

Jan 1, 1974

Investigations into the flotation behaviour of single minerals, mineral mixtures and ores at the CSIRO Division of Mineral and Process Engineering have led to the development of sophisticated laboratory flotation testing equipment. Both routine and complicated flotation investigations can be conducted in a precise and reproducible manner using procedures and equipment that have been refined over many years of conducting careful batch flotation testwork. Several important advances in flotation research can be attributed to changes in testing procedure developed as a consequence of the availability of this equipment. The flotation cell and ancillary equipment is described and associated developments and techniques discussed.

Jan 1, 1992

Modern mining and coal cleaning techniques lead to the generation of large quantities of fines which give rise to problems in their storage, handling, transportation and further processing. Pelletisation, a method of particle agglomeration, can alleviate such problems. This paper provides a brief overview of the principles of pelletisation and a survey of the coal pelletisation literature. Then it reports results from an experimental investigation of the effect of surface active reagents on coal pelletisation. Finally the paper is concluded with a few remarks on applying the results from the experimental study to practical coal agglomeration.

Jan 1, 2000

Mining projects frequently fail to meet their financial objectives. A significant area of poor performance lies in the areas of resource estimation, reserve definitions, selective mining and metal accounting. The processes leading to the exploi

Jan 1, 1998

In the human body, the balance between heat production and heat loss is continuously being disturbed, either by changes in metabolic rate (work being the most influential) or by changes in the external environment (heat stress), which alters heat loss. These changes in body temperature can adversely affect the function of body systems and organs. As a result, heat production or heat loss processes are triggered in order to restore normal body temperature (36 - 37¦C). If the heat generating systems of the body are excessive or the environment hostile then the capacity of the body to maintain thermal homeostasis is exceeded and can lead to a serious threat to health, or even death. This health deficit can severely affect an individualÆs capacity to work optimally; the end result is both poor productivity and health. Strategies to minimise or eliminate this effort will benefit both the health of workers and the productivity of companies. The principal strategies to reduce the effects of the environment on workers are: engineering interventions: to improve environmental conditions and reduce heat stress; and a comprehensive working in heat protocol: with provisions to identify risk situations and procedures to be adopted in relation to these. The above points will be discussed in detail with practical and simple strategies proposed to combat the deleterious effects of heat in mining.

Jan 1, 2005

The growth of the mining industry around Australia over the last ten years has seen many open cut mines developed on shallow oxide reserves. Most of these have been gold operations, although there are some copper mines in the list, too. Many of these have exhausted their oxide reserves and have made the transition to underground mining to access their deeper sulphide ores. Other operations have reached or are approaching the point where the decision has to be made to go underground or cease mining. This paper discusses the issues involved in making the transition from surface to underground mining. The aim is not to discuss each of the issues exhaustively. This would take a conference in its own right. Nor is it intended to provide a primer on underground mining. Instead the aim is, firstly, to flag the issues which must be addressed when planning to make the transition from surface to underground mining and, secondly, to identify critical aspects of mine development.

Jan 1, 1997

By Durao F

A multi-layer feed-forward neural network was trained (using the error back-propagation algorithm) to learn a subset of rules designed to stabilise the performances of the copper flotation section of a complex sulphide processing plant and then tested in order to evaluate its expert performances. Two types of neural networks were compared: the classical ones, fully connected between one layer and the adjacents (with different architectures), and entropy networks, partially connected and generated according to a methodology that simplifies its building up. The advantages and drawbacks of both were analysed and compared with classic (rule based) expert systems.

Jan 1, 1995

By K Paki, K Parker, J F. Dupont

The Mount Charlotte grinding circuit at KCGMÆs Fimiston mill was recently equipped with three 650 mm CAVEX cyclones in order to improve the overflow P80, reduce the fines bypass to the underflow and improve the underflow density/recovery of water to the overflow. After the first two sets of surveys were conducted air core boosters (ACBs) were installed on the 650 mm CAVEX cyclones in an attempt to further increase their performance. JKTech was approached to assist with the examination of the data obtained from the surveys; this data was intensively modelled to determine, to a high degree of confidence, the impact the changes to the cyclones had on the classification and the benefits to the plant. This paper outlines the outcomes of the trial and the methods used to determine those outcomes.

Jan 1, 2007

A very sensitive high-speed two-colour pyrometer was built to measure the temperature of single particles of sulphide mineral, typi- cally 50 pm in diameter, as they burnt while entrained in a hot gas stream. The pyrometer has been used to study the burning of pyrite and chalcopyrite particles and has thrown light on cenosphere formation. Measured maxi- mum temperatures have been compared with values predicted by diffusion-based models. The pyrometer has also been used to study the burning of small captive pellets (2-9 mmm dia- meter) of lead-zinc concentrate.

Jan 1, 1984

Mount Isa Mines Limited commissioned the Heavy Medium Plant in August 1982. The first processing stage using Mogensen Sizer 2056 dry screens, experienced unresolvable cloth blinding problems in attempting to separate fine, damp Lead/Zinc ore at 1.7 mm. A large proportion of the fines incorrectly reported to oversize and hence to the wet preparation screens. This wet preparation screen overloading produced multiple operating and maintenance problems. The plant configuration precluded retrofitting any alternative proprietary screen. An internal Mount Isa Mines research and development programme was established to design and build a screen to achieve the required per- formance within the site constraints. The resulting ISA SIZER screen has exceeded metallurgical performance expectations. A `clean sheet' approach to the design also permitted elimination of maintenance difficulties experienced with the Mogensen Sizer. Four `production model' ISA SIZERS were installed in February 1988. The ISA SIZER screen, now fully developed is available commercially and will satisfy many screening plant requirements.

Jan 1, 1988

Geologists employed by Metals Exploration Pty. Ltd. discovered nickel enrichment at Greenvale, 180 kilometres West of Townsville, in 1967. Subsequent drilling proved an ore body containing 45 million dry tonnes of ore containing an average of 1.5% nickel and 0.11% cobalt. The Freeport Minerals Company, who had experience in treating lateritic nickel ore, were invited to participate in development of the ore body. This resulted in the formation of the operating company Queensland Nickel Pty. Ltd., jointly owned by Freeport Queensland Nickel Inc. and Metals Exploration Queensland Pty. Ltd. With the completion of successful pilot plant testing of Greenvale ore at the Freeport research facilities at Belle Chasse, Louisiana, a treatment plant was constructed at Yabulu, 24 kilometres North West of Townsville. A 225 kilometre railway line was built connecting the Greenvale Mine and Yabulu Treatment Plant. The ore reduction and ammonia/ammonium carbonate leaching flowsheet is similar to that constructed and operated by the Freeport Minerals Company during World War II at Nicaro, Cuba. Modifications to the Nicaro flowsheet implemented at Yabulu include facilities to recover cobalt in a mixed nickel/cobalt sulphide product and the reduction of nickel

Jan 1, 1978

By Burrell I

This paper describes recent developments at West Cliff Colliery in environmental monitoring, using a sophisticated computer controlled system. The operations involved in environmental monitoring are described and the equipment employed is detailed. It is anticipated that the monitoring system employed at West Cliff Colliery will be expanded to allow total and instantaneous monitoring of roadway environmental Conditions.

Jan 1, 1983

By Weller KR

Completely dry or completely wet materials are comparatively easy to screen, but materials with moisture contents between these two extremes can present varying degrees of difficulty. The presence of moisture can impair the performance of a dry screening plant in a number of ways: ò agglomeration of fine undersize particles onto larger oversize particles, resulting in the fine particles being misplaced to the oversize; ò increasing attractive forces between particles that hinder stratification and particle presentation to the screen; and ò blinding of the screen apertures caused by fine moist particles clinging to the screen which reduces the effective aperture size and the open area of the screen. Test work on full-scale screens has shown that the agglomeration of fine particles onto larger particles only occurs once the equilibrium moisture content of the ore is exceeded, and that the quantity of adhering fines present is proportional to the surface area of the larger particles. An -adhering fines screen model has been developed from this work, and by using relationships derived between the model parameters and feed moisture content, the effect of changes in feed moisture on both product quality and operation of iron ore dry screening plants is predicted.

Jan 1, 1993

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, 1994