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By Wickham P

Digital computer based control systems are used to implement control and monitoring over most unit operations in Mount Isa Mines Limited lead-zinc concentrator and copper concentrator. Implementation has been gradually devel- oped and expanded since the first process computer installation in 1969. Operations currently using high level control logic include crushing, grinding, on-stream analysis of flotation products, flotation reagent additions, and tailings thickening. Details of gains in metallurgical efficiency for each system are considered.

Jan 1, 1978

Construction of Western Mining Corporation's nickel refinery at Kwinana, Western Australia, commenced in July, 1968. Production of 15,000 tons per annum of refined nickel metal will commence early in 1970, The plant will also produce approx- imately 150,000 tons of ammonium sulphate0 The ammonia leach process which was developed by Sherritt Gordon Mines Ltd., and has been in operation at their plant at Fort Saskatchewan, Alberta, Canada, for the past 15 years, will be used at Kwinana. The refinery will cost approximately 435 million, and will employ upwards of 250 people.

Jan 1, 1969

By Heinrich CA, Wall VJ, Walshe JL

The Porgera Gold Mine, located in the highlands of Papua New Guinea, has produced over 5 million ounces of Au, since its opening in late 1990. The deposit is located within Upper Cretaceous Papuan Platform sediments approximately 25 km south of the Lagaip Fault, and is spatially and temporally associated with the 6 Ma alkaline Porgera Intrusive Complex.

Jan 1, 1995

By S R. Grano, J Duan, T A, D Fornasiero

We have determined the experimental rate constants for chalcopyrite particles floated from a complex sulfide ore and compared them with those calculated using a recently developed flotation model. The model incorporates contributions from the efficiencies of collision, attachment and stability between particles and bubbles, as well as their frequency of collision. For these calculations, the contact angle of the chalcopyrite particles in the ore was obtained independently using a surface spectroscopic approach. The calculated flotation rate constants were in good agreement with the experimental data and able to reproduce the characteristic maximum in flotation rate constant for particles of intermediate size. The values of bubble velocity and turbulent dissipation energy derived from these calculations are relatively low and may well correspond to mean values of these parameters inside the flotation cell. We have extended this approach through the application of a property based model to an operating plant, with a satisfactory outcome.

Jan 1, 2005

The use of black and white and colour infrared film in remote sensing of natural resources, is reviewed. In heavily-forested areas such as New Zealand, the main value of the method is in surveying the vegetation cover to detect the existence of plant communities characteristic of specific geological formations, By contrast, in and areas of Australia where the vegetation cover is sparse and where rocks and soils are well exposed, the method can be used in detecting different rock types or other geological differences.

Jan 1, 1971

By Tomlinson R. C

The paper will briefly describe planning in the National Coal Board (NCB) and the contribution that operational research makes to it. It will then give details of some of the models in use and will finally consider critically the problems of looking ahead to the next century.

Jan 1, 1977

Changes in prices and costs change the mineable grade and the profitabil- ity of an ore reserve. In a static world the grade required for an ore reserve is measured by the ratio: Cost/tonne of ore x 100 Price received/tonne of product and profitability by the ratio:- Price received/tonne of product Cost/tonne of product If the words cost and price refer to average cost and average price over some suitable period, say 3 to 5 years, the above ratios express the convent- ional wisdom of the mining engineer, and assume there will be no change in technology or politics.

Jan 1, 1979

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 Paine G

Kidston Gold Mines commenced mining in 1984 and currently mine approximately 10 million tonnes per annum of ore and waste using a conventional truck and shovel open pit method. The overall mine grade is a low 1.82 grams per tonne.The mineralisation is generally uniform within the ore zones and mining boundaries are staked out from blasthole assays according to pre-determined cut-off grades. Buffer blasting is necessary to minimise post-blast lateral movement of in-situ grade for digging control.The characteristics of the rock currently mined vary widely from soft oxidised to hard unweathered rocks. Blasting problems have been experienced during the initial mining phase in these harder rocks.

Jan 1, 1986

The beneficiation of heavy metal oxides, such as iron ore, is usually performed with heavy medium separation in cyclones, static baths and lately with Larcodems. Atomized ferrosilicon is most suitable as a heavy medium at densities above 3600 kg/m3 whereas a mixture of milled and atomized ferrosilicon is suitable at densities below 3600 kg/m3. When operating a beneficiation plant at densities higher than 3600 kg/m3 the quality of the ferrosilicon particles is an important factor that influences the control of the beneficiation process. Therefore, it is important to know how the rheology would be affected by the ferrosilicon quality as it also influences the control of the process at these elevated densities.

Jan 1, 2002

This work describes preliminary laboratory testwork to study the relative leaching response to cyanidation and thiourea leaching of an oxidised low grade gold ore. The potential of an alternative lixiviant like thiourea to commercial processing of mine dumps is discussed by specific reference to selected case histories. It would appear that on the basis of the available published information, there could well be a case advanced for the acid thiourea leaching of sulphide concentrate tailings being subjected

Jan 1, 1994

The use of coal as a fuel for heat and power generation has a long history. During the nineteenth century most of the present combus- tion technologies were pioneered, as shown in Table 1, This period was associated with the "golden age" of coal and its contribution of almost 80% of the world's energy demands in the early,1900s . The decline in the use of coal has been due to the transfer of the heavy transportation area to diesel power, the elimination of coal as a household fuel and the substitution of oil for coal in power plants. Coal remains the major fuel for the electric utility industry and the present paper will be concerned primarily with that application. Table 1 outlines the development of coal tech- nology with the parallel understanding of coal as a material and its behaviour during combus- tion. Clearly many developments in combustion technology have occurred in this century, although most of the processes had been invented in the nineteenth century. Also, the great expanse in coal research of the past few decades has led to a greater understanding of the coal combustion process.

Jan 1, 1987

To carry out its responsibilities the SECV needs to manage the visual environment effectively. Every land oriented decision effects what we see and the value in pursuing visual excellence is supported by informed opinion, widespread community interest and evidence of cost- effectiveness.By knowing how we perceive the landscape and then changing or conserving it we can assist in fostering a positive mental image of a countyside which is welcomed by the local and regional community.It is useful to examine key design elements and the value we place on visual impressions in relation to three significant SECV rehabilitation projects, at Loy Yang, Newport and Morwell Open Cut.

Jan 1, 1992

By H R. Phillips

The ventilation and refrigeration design of underground mines is an important aspect, when new or existing mines are considered and places a great responsibility on engineers tasked to do so. The current trend for both local and international underground mines is to extend their search for valuable ore reserves deeper below surface. In South Africa, the predictions are that about 40 kt of actual gold still lies in situ, ready for extraction. As mines extend their search for minerals of economic value deeper and deeper into the earthÆs crust, ventilation and refrigeration aspects of such mines become more prominent than before. The planning and design of the required ventilation and refrigeration within these mines, over their expected lifetime is important including the practical implications of such designs. Technology changes and improvements need to be incorporated into ventilation and refrigeration designs, where possible and advances in this specialised field explored. This paper explores ventilation and refrigeration design aspects within the underground mine sphere. Aspects such as mining depth, virgin rock temperature (VRT), mining methods, and different cooling applications available including ventilation supply are reviewed in design applications. Heat generally becomes a significant aspect to counter in these mines and they are not always necessarily deep mines.

Jan 1, 2005

By Herbst JA

During the last decade, it has been established that conventional mineral-processing control strategies based on classical control theory result in significant increases in plant throughput and operating-cost saving. The proper education and training of personnel using dynamic simulators of the principal unit operations is vital for proper design and maintenance of control systems. Severe multivariable interactions and numerous constraints on both manipulated and state variables in grinding/classifica-tion and flotation systems can be studied using time domain analysis with proper dynamic simulators. Two interactive programs are described, and the basis of each simulator and its structure are discussed. Two examples concerned with choosing, tuning, and decoupl-ing of manipulated and controlled variables for a grinding/classification circuit (DYNA-MILL II) and for a rougher flotation circuit (DYNAFLOAT II) are presented. The way in which these dynamic simulators can be used for the design of model-based control strate-gies is also outlined. A brief description of the use of these dynamic simulators for screening alternative strategies and circuit optimization is given.

Jan 1, 1985

When a joint venture is established between a major and a minor, the co-venturers often have a number of divergent interests; the major may have put up significantly more capital into the project and will want to protect its investement; the major may have more financial resources and be more readily to commit capital to the project; the major may have more technical resources and expertise to provide to the project; the major may have other competing demands for its capital; the minor may be relying on rapid development of the project as its sole source of cash flow. Successful joint ventures arise when the co-venturers understand each others' interests and attempt to satisfy these interests. This could be achived by having a clear process and timetable for development of the project coupled with clear rules for distribution of income, the commitment of capital to the project and the provision of inter-company services. If divergent interests are either regulated clearly or eliminated, both co-venturers are more likely to seek common objectives in the joint venture with less scope for conflict. This paper, written from the perspective of a major, examines means of establishing successful joint ventures between majors and minors.

Jan 1, 1997

By D M. Weedon

This paper introduces a novel roll crusher design, which incorporates non-cylindrical crushing rolls. The use of non-cylindrical rolls enables the crusher to achieve a greater reduction ratio than is possible with conventional roll crushers. Referred to as the NCRC (non-cylindrical roll crusher), the new crusher incorporates two rolls comprised of an alternating arrangement of plane and convex or concave surfaces. The two rolls are complementary and arranged so that when they rotate the convex and concave surfaces of each roll are substantially opposed. With the rolls rotating in opposite directions at the same speed, this arrangement produces a gap between the rolls that remains approximately constant. Discontinuities on the roll surfaces provide improved angles of nip, which increase the probability of larger particles being drawn into the crusher. Initial tests on a scale prototype of the NCRC have indicated that reduction ratios exceeding 10:1 are achievable.

Jan 1, 2000

By R Farana

The future challenges in mining instrumentation, mainly on future intelligent mines, are to continue providing instruments with the highest level of reliability at the lowest possible cost, and also to take advantage of technology existing in other industries and to adapt it to the mining context. New wireless instruments (smart sensors, smart actuators, smart controllers) would also be very useful, as well as instruments fully adapted to the monitoring of large movements that are observed, in both underground and open pit mines. Mining instrumentation is found to various degrees in most mines, both open pit and underground. Smart mining instruments present a certain number of aspects specific to the environment in which the instruments are installed. Namely, the instruments can be installed either for short-term or long-term purposes. The mining industry is always looking for useful instruments that can provide relevant information on ground behaviour adjacent to mining stopes or permanent infrastructure. The instruments must meet the various criteria, and must also evolve with the new mining technologies that are continuously being implemented. A strong collaboration between the mining industry, research organisations, and instrument manufacturers is the key to meeting these objectives. This contribution describes the current trends on smart sensors and smart instrumentation with Wireless LAN support.

Jan 1, 2003

Platinum Group metals have been known in New Zealand since the 1880's but not produced on a large scale. They have been neglected because their value was not appreciated rela- tive to gold and their value was often very low, reflecting demand, and because recovery was difficult compared with recovery of gold. With the rising price of most Platinum Group metals and the perfection of gravity and flota- tion recovery methods, recovery of platinum along with gold from alluvial deposits is more attractive. Platinum Group metals are known in several different environments in New Zealand, ranging from alluvial placer deposits to layered basic to ultrabasic intrusions and quartz veins. None of the known occurrences have been ade- quately prospected and there is a real possibi- lity of future discovery of important deposits. Several New Zealand based and at least two offshore resource companies are currently involved in exploration, prospecting or mining for Platinum Group metals in New Zealand.

Jan 1, 1987

In the years prior to the outbreak of war in 1939 Australia's production of copper had declined from a peak of about 80,000 tons in 1911-1915 to approximately 25,000 tons in 1939. This production met the need of the slowly growing national requirement and gave an excess for export. However, with the intensification of the war effort in 1942 due to the imminence of a Japanese invasion of this country, or at least a blockade of the sea lanes, it became necessary to expand production of armaments, and consequently the demand for copper increased beyond the capacity of the industry. Importation of copper to Australia during the period 1940-1944 was 131,000 tons.When exploration of the Mount Isa orebody was first being carried out in 1928, No. ID diamond drill disclosed the presence of some copper ore lying outside the limits of the Black Star orebody2, but it was not until 1941-1942 that the development of No. 7 level in the Black Star orebody enabled the existence of a lode of copper ore of economic grade to be established. At the request of the Commonwealth Government of the day a programme of development for copper production was undertaken whilst lead smelting was continued as before the war.A series of flotation tests on up to 1,500 tons of ore at a time, was undertaken and the concentrate so obtained was stockpiled. These tests were conducted, using one section of the lead mill, and demonstrated that a concentrate grade of 22-23% Cu with a recovery of 80-85% might be expected.These recovery figures were afterwards much improved, and 93-95%was obtained before the close of smelting in 1946.

Jan 1, 1953