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From 1980 to February 1991 the Rosebery concentrator purchased ore from Aberfoyle's Que River Mine. Following the termination of the contract the concentrator reverted to treating Rosebery ore alone. Since that time it has become apparent that the circuit configuration employed was no longer optimum for zinc metallurgy. The circuit was designed to treat a difficult, slow floating sphalerite; however, the opposite was now found to be true. The sphalerite is fast floating and the circuit was cumbersome. During 1992 extensive circuit changes led to the provision of a simple open circuit flow sheet. The circuit is now easier for operators to understand and lends itself to improvements in process control. Middlings streams have been minimised, which produces a far more stable circuit. Significantly, it must be noted that the key to achieving potential results must lie in reducing variations within the process. A significant ore characterisation program has been undertaken, providing an insight into the metallurgical compatability of the ore to be mined. Using the information collected in this program, metallurgical recoveries and grades can now be predicted with a geater accuracy. Ore characterisation data suggests that an improvement from a 54 per cent zinc concentrate to a 57 per cent zinc concentrate should be achievable. By understanding the size-by-size mineral assemblage, a strategy for concentrate grade improvement has been developed. The requirements of the customer must in all cases determine the quality of the product. Pasminco is a fully-integrated zinc producer and as such significant gains can result by tailoring the concentrates to suit the Smelters.

Jan 1, 1993

By Swanson AR, Nicol SK

A study has been made into the influence of feed size distribution on the flotation response of coal. The results show that a full description of the flotation response of a coal must not only consider the inherent floatability of the coal, but also, the size distribution of the feed to flotation. The performances of a number of flotation circuits were compared using a coal which was "poorly floating" because of its size distribution. Split feed flotation, two stage reagent addition, and reflotation of classified tailings all gave better yields than that obtained by conventional single stage flotation. The optimum flotation circuit for the washing of the coal in question, was reflotation of classified tailings.

Jan 1, 1978

By Gadd D. E

Since October 1972, New Zealand Steel Mining Ltd has loaded around 10 million tonnes of ironsand concentrate from single-point mooring buoys located off-shore at Taharoa on the west coast of the North Island of New Zealand. Before the first off-shore loading system was installed a considerable research effort was applied to proving the slurry loading technique. Subsequently the system has been expanded and a new buoy, pipelines and pumping system were installed in early 1978. Since then 110,000 DWT class ore carriers have been loaded at rates of around 2600 tonnes per hour through twin submarine pipelines. This paper reviews the operation of the shiploading system and attempts to answer the question: "If the Taharoa operation were to be planned in 1980, would the same research spending be necessary or have published research results since, made such practical tests unnecessary?".

Jan 1, 1980

Rare-earth permanent magnetic roll separators, pioneered by our group a few years ago, have distinctly different operation characteristics compared to prior art electromagnetic separators of various types. Many new applications for dry high-intensity (or better: high-force) magnetic separation have been developed in a short time period. It has also been found that the new generation of separators generally are more efficient with regards to removal of weakly magnetic contaminants in glass and ceramic raw materials with minimum loss of valuable product compared to induced magnetic roll (IMR) separators.The latest development is in the area of production of clean magnetic concentrates at high recoveries. It is likely that the PERMROLLR magnetic separator will replace cross-belt and lift-type magnetic separators as a result of this most recent advance.The paper will review the features of the PERMROLLR magnetic separator in comparison with other types of magnetic separators on the market and give examples on applications.

Jan 1, 1990

Results of blasting trials conducted at Gregory Mine, a large open cut coal mine situated in the Bowen Basin, show that fragmentation was improved or equalled whilst reducing the amount of explosives previously required. This was achieved by a system of deck loading whereby two or more explosive charges, separated by air gaps, were positioned in the blast hole, thereby extending the effective explosive column whilst minimizing the total explosives required. In the three trials to date, a saving of approximately 213 kg of ANFO per blast hole was achieved. This represented an approximate 20% reduc- tion in ANFO requirements.

Jan 1, 1989

Resource developers in Papua New Guinea (PNG) are now, more than ever before, confronted with land-owner related issues that can hinder their corporate objectives.Development of PNG's custom-arily owned land since independence has brought sudden changes with mixed success. Exploitation of mineral resources has had its share of problems, and Highlands Gold Limit-ed's (HGL) endeavours in the central Highlands of PNG are no exception.

Jan 1, 1994

Infrastructure is defined as all those parts of a mining development which are not directly concerned with mining and mineral processing. Infrastructure is of significant and growing importance in the overall develop- ment of mines, and the costs could be critical in determining the viability of a project. Prior to_project authorisation, feasibility studies are required, often in considerable detail, to determine costs with adequate reliability. It is necessary that the Engineer should be adequately briefed for carrying out these studies and that good liaison and communication with the Owner be maintained. Methods, costs, order of accuracy, and some special requirements of these studies are discussed. After project authorisation, rapid im- plementation of the proposals is generally desired. A suggested organisation and method for this implementation is presented and dis- cussed. Comments on fees, and particular points in the relationship between Owner and Consulting Engineer are given. Particular reference is made to differences in conditions compared with public works projects. Realistic attitudes of mind towards environmental matters, industrial relations, and contractual relationships are advocated.

Jan 1, 1974

By Yushan Ma, Jiqing Wang, Hanyi Jia

The Hedong Gold Mine is located in the Yantai area, Shandong province, China. It is an underground mine with an annual gold output of some 700 000 grams. The orebody is located on the edge of the Wanger Shan metamorphism zone, and the hangingwall of orebodies is thus defined by a prominent set of fractures. The proximity of the metamorphism zone and the inclusion of the fracture set ensure that both the orebody and the country rocks are unstable. The main orebodies dip at an angle of between 40 to 45¦, with a strike length of 160 metres and a horizontal width of 50 metres. Surface subsidence in the area is not permitted. Cut and fill mining is usually practiced. As the mining operation proceeds to greater depths, the ore grade is diminishing and it is necessary to find a more efficient stoping method. Sublevel open stoping with sequential extraction and filling of each sublevel has been designed and applied in situ. This new mining method is called æsublevel open and fill stoping methodÆ in the mine. Experience to-date is that new mining method is satisfactory.

Jan 1, 1998

Zinc concentrates from the newer mines and from proposed developments provide both opportunities and processing challenges to the conventional roast-leach electrowin smelters. These concentrates are often characterised by low iron, elevated silica, possibly high manganese, and levels of elements such as germanium which may cause concern. In addition, environmental constraints on residue disposal are forcing significant changes to some smelter practices. Iron in concentrate, and the resulting environmental impact of residue disposal are now major questions. However, normal concentrate tariff structure provides a disincentive against smelters taking high grade concentrate and oxide fume. Processing technology to cope with these changes is reviewed, as is de-watering and materials handling of ultra-fine concentrate. Within a few years, such fine concentrates will account for up to 1 000 000 t/y of contained zinc. New processing technologies including novel transport methods, siliceous leach circuits, manganese removal cells and front-end smelting will become significant in zinc smelting.

Jan 1, 1993

The problem of manufacturing from sulphuric 'acid and Christmas Igland "A" phosphate, superphosphate of acceptable physical condition and agronomic phosphate availability, is directly related- to the crystallisation of a reac- tion product, monocalcium phosphate monohydrate. Two solutions to the problem, vacuum drying the superphosphate and calcination of the ore before reaction with acid, are discussed.

Jan 1, 1971

By Langberg D, Gray N. B

The flocculation of hydrophobic magnetite with gold was examined as a possible means of recovering fine (95 per cent were possible for 1.5 - 3.0 ¦m and 5.5 - 7.5 pm gold sizes. The effect of process variables on the flocculation process was explained by variations in the adhesive force between the gold and magnetite.

Jan 1, 1991

By Taylor L. M

Accurate computer prediction of the muck pile produced by a conventional blast requires modeling of the physics that occurs during the rock motion phase of a blast. The ability to predict the motion and the subsequent muck pile can have a significant economic impact on the mining industry. Some of the computer programs previously used to predict rock motion employed polygonal elements with comers and sides to model the rock (Cundall, 1971; Walton, 1982; Taylor, 1983). This approach allows the elements to bulk because of the corners and the aspect ratio. However, tracking the many interactions of the comers and sides of the elements is a computationally intensive process. Several other rock motion computer programs were developed that employed spherical elements, (Schamaun, 1984; Gorham-Bergeron et al, 1987) but they lacked correct bulking mechanisms or could not be vectorized for efficient execution on vector processing machines. A new spherical element code called DMC (Distinct Motion Code) (Taylor and Preece, 1989a, 1989b) has been developed this past year. DMC was designed and written to take advantage of super-computer vector processing capabilities. The efficiency has also been increased through the use of spherical elements, explicit time integration and a new contact search algorithm. When spherical elements were chosen for efficiency, some physically correct mechanisms for capturing the bulking behavior of the rock mass also had to he developed. This paper will treat several mechanisms that were developed to allow spherical elements to exhibit correct hulking behavior.

Jan 1, 1990

Among the various methods of thick-seam mining already well-tried in practice longwall caving with extraction of a single slice, as thick as possible, abandoning the top and/or the bottom coal, seems to be the most suitable one for the Australian coal mining industry. The production units of the future should be equipped with heavy double-drum shearer-loaders, wide armoured conveyors, (with one or two central chains) and shield support. Material of this type has been developed for seams up to 6 m thick. Output figures of more than 6,000 tROM/d from a single face can be looked upon as a quite realistic expectation. The problems of co-ordinating such large production units with the whole layout of the mine are discussed. The factors to be taken into account in the planning work and for preven- tion of mine fires caused by spon- taneous combustion are dealt with. For economic reasons the highest possible utilization factor of the very expensive equipment must be aimed at. Furthermore, the seams or parts of seams to be extracted should be carefully selected.

Jan 1, 1976

By Thomas W

Due to record low tin prices and an uncompetitive position in world markets, the Renison tin mine has undergone three major phases of restructuring in the last three years. This has involved substantial job losses, almost all of which have been through voluntary retrenchments. Retrenchments took place in 1988, 1990 and 1991.The last phase of restructuring was the most dramatic, as many aspects of the operation of the mine were changed. New pay structures were introduced, and the miners' contract system was scrapped. Drastic pay cuts occurred in many areas, although the opportunity was also taken to increase pay at some of the lower levels where inequities existed. Work practices were changed, as was the management structure.

Jan 1, 1992

The paper is introduced by some general comments on the Electrolytic Zinc Company West Coast Mines operations. An outline of the geology of the Rosebery Mine orebodies preced- es a resume of the mining methods used prior to the current mechanization programme. The reasons for the introduction of longhole stoping techniques are given together with a brief explanation of both sublevel longhole and longhole stoping methods. The application of remotely controlled loaders within these stoping methods is discussed. A description of the remote control mechanisms, used on Atlas Copco 310 and 511 Cavo loaders, is followed by comments on these mechanisms from both a maintenance and production viewpoint. A summary of perform- ance statistics and operator safety records vindicate the selection of remotely controlled loaders for the longhole stoping areas at Rosebery Mine.

Jan 1, 1977

The paper examines the possibility of applying the monolithic packing technique developed in the UK to the division of wide development drivages in Australia, so enabling double entries for longwall retreat panels to be created from shortwall units. The monolithic pack of the UK therefore becomes a monolithic partition in this proposed Australian application. A method developed for the analysis of the load development in packs installed behind longwall advancing faces is adapted and used to predict the support performance of the monolithic partition. Conclusions are made regarding partition construction and possible rates of advance.

Jan 1, 1986

By B McIntosh

Sustainability in its simplest assessment has been defined as æmeeting the needs of the present without jeopardising the needs of future generationsÆ. For the mining industry alone, this statement could indeed be interpreted by the many cynics in our community as an oxymoron; as miningÆs very existence requires the extraction and consumption of finite resources. However for the future of industry as a whole, the integration of mining, minerals processing and manufacturing presents us with a unique opportunity to achieve sustainability through the continued supply of metals and materials for society, in a manner which can achieve positive social outcomes through a triple bottom line approach.The Kwinana Industrial Area has been Western AustraliaÆs premier heavy industrial precinct for more than 40 years and its prevailing level of prosperity will ensure it remains a significant contributor to the State economy through the 21st century.The Kwinana industries depend on each other for the production of essential raw materials vital to their manufacturing and refining process, an innovation that also has significant environmental benefits.Formed in 1991, the Kwinana Industries Council strives to foster positive interaction between member companies and with the local community.The aims are:to co-ordinate the activities of Kwinana industries on a range of common issues; provide effective liaison with the local community; promote a positive image of Kwinana industries; highlight contributions to the community by Kwinana industries; and work towards the long-term viability of the Kwinana Industrial Area. The Kwinana Industries Council facilities these aims by focusing on developing and employing leading edge technology, giving workplace health, safety and environment top priority, and taking a committed, responsible and pro-active approach to environmental protection, whilst forging a two-way partnership with the local community.The sustainability of industry is the key objective for the Kwinana Industries Council and through the involvement of the 13 member companies industry strives to:achieve efficient processing of resources to provide a range of goods and services needed by the community; achieve acceptable and decreasing level of environmental impact; provide jobs and income for our community; and engage co-operative projects that benefit the local communities, the State and Australia.

Jan 1, 2004

The Coal Corporation of New Zealand Ltd (CoalCorp) is the largest coal producer in New Zealand, with extensive properties in both the North and South Islands. CoalCorp's North Island operations are kilcmetres to the south of Auckland. opencasts, are located in the catchment wildlife, historical and scenic values. in this catchment is the single most mining operations. centred on Huntly, a town some 80 Five coal mines, four of which are of Lake Waahi, a lake with significant The discharges of mine lodgement water important environmental constraint on Throughout New Zealand the use of water is controlled by a statute called the Water and Soil Conservation Act 1967. All industrial water users are required to hold Water Rights, which are in effect licences to take, use, dam, divert or discharge water. Water Rights are obtained through a legally defined process and any potentially affected party has the per to object to their granting. A special tribunal hears the evidence for and against an application, and issues its decision, which is reviewable in a higher court on Appeal. Rights, if granted, are issued subject to conditions and, in the case of mining discharges, limits would be set on flaw rate, suspended solids concentrations, turbidity, pH and the concentrations of any potential toxicants. This paper presents a case study of an integrated, catchment wide water management plan for Lake Waahi, that was prepared by the author, and others while the author was in the employ of CoalCorp, and its predecessor, State Coal Mines. The author is grateful to CoalCorp for their permission to submit this paper.

Jan 1, 1988

By Roberts C

The satisfactory testing and characterisation of mineralisation amenable to heap leaching, is of prime importance to successful operation of a project. This paper outlines a methodology for assessing material suitability. A general model is used for classing material types for suitability for treatment and for economic analysis. The four levels of these are overburden, oxide, transitional and unoxidised materials. During exploration, reverse circulation (RC) drilling can be used effectively to define these zones by a combination of logging, analysis and provision of cuttings for column leach and bottle roll trials. RC cuttings can he used effectively for column leach trials, when calibrated against conventional processing-sized samples, obtained from surface. Tbis allows metallurgical testing to depth and definition of transitional ore types and the base of oxidation, accurately and economically with an acceptable density of samples. The accurate prediction of base of oxidation and variations in recovery with depth and ore types can be used to develop 'economic' pit designs with zones of variable recovery. Petrological studies of leaching results and examination of mineralisation types carried out on concentrates, provide information on gold distribution and physical and chemical constraints. The examination of concentrates can be particularly useful for types of mineralisation when overall gold content is frequently at or below one pan per million. Explanation of anomalous recovery of gold grains in dense goethite and solution-robbing by carbonaceous material can be identified by use of petrological and scanning electron microscope. An understanding of the role of the host rock in leaching characteristics can also he provided by petrology where siliceous or clayey materials can require significantly different treatment.

Jan 1, 1994

In epithennal deposits changes in the character of mineralization in depth and time are conspicuous and abrupt at the interface between supergene and hypogene zones. As the reaction zone migrates downward as a consequence of surface erosion, previously deposited minerals are placed in unstable chemical enviromments and dissolved. This reaction takes place at the base of the epithermal precious metal zone. Examples at Cerro de Pasco, and Casapalca, Peru; Carlin, Nevada; and porphyry copper-gold deposits are cited.

Jan 1, 1991