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By Abrahamsson S, Niklasson B

In a follow-up of 12 production blasts in a quarry at the Mrica project on Java, tightly spaced porous bands were found to govern fragmentation to the extent that the average fragment size k5o was nearly independent of the specific charge within the range 0.30-0.56 kghn3. This fording resulted in a reduction of the running costs for drilling and blasting by 20-40%. Our work has given considerable practical benefits and insights into the blasting process, even if the results were of no direct use to check out fragmentation predictions based on models, which was one of our main Goals.

Jan 1, 1990

Comalco Limited has recently completed construction of a $50 million kaolin plant at the site of its bauxite mining and industrial minerals operations at Weipa. The plant will produce 100,000 tonnes per annum of coating grade kaolin for the paper industry.Comalco produced the first coating kaolin from the deposit in 1979 on a trial basis. Since then a variety of quality coating grades with specific particle ize distributions and brightness values have been prepared.Extensive drilling and bulk sampling of the deposit over eight years has shown that the orebody is large and of a high grade suitable for the production of premium quality coating kaolins.The processing plant technology was developed by Comalco in association with the European kaolin and equipment producer Amberger Kaolinwerke GmbH (AKW).The Weipa kaolin plant is the first of this size to be built in the Pacific Basin region and it will offer the region's paper-coating mills a stable and reliable source of high-quality kaolin, shipped from an established bulk loading port. The paper provides an overview of the development of the kaolin investment, the nature of the production process and details the project management procedure used for the design, construction and commissioning of the plant. Three areas of significant interest, the gas turbine fired pray dryer, the moving bridge shiploader and the use of aerobelt conveyors on the project are detailed.

Jan 1, 1988

By Takagi T, Seetharam R, Sie SH, Naito K

Tin-polymetallic vein type deposits are one of the major source of metal producers in the Circum Pacific Belt. This type of deposit is of great importance for the modem electronics and medical industries because of their high content of rare metals (especially indium and bismuth). We have studied two representatives, Tosham of India (Cu-In-Bi-Sn-W-Ag-Au), and Mount Pleasant of Canada (Zn-Cu-In-Bi-Sn-W), using proton and electron microprobes in order to delineate the distribution of medical/high-tech rare metals. The electron microprobe study showed that major indium carrier in such type of deposit are roquesite (CulnSZ), sphalerite, stannite and a Cu-Zn-Fe-In-Sn-S mineral; and that indium is incorporated in sulfides by coupled substitution like Cu + In = 2(Zn + Fe). The proton microprobe showed that indium at trace levels is also present in chalcopyrite and pyrite. In addition, zinc, copper, arsenic, antimony, selenium, tin, and bismuth are common in chalcopyrite and pyrite. Arsenopyrite contains nickel, copper, zinc, silver, tin, antimony and bismuth. In chalcopyrite and pyrite, zinc, arsenic, indium, bismuth and lead are higher in Mount Pleasant ore, but silver is higher at Tosham. Also thallium and gold were found only in Tosham pyrite. The Tosham deposit is genetically related to S-type magma, while the Mount Pleasant deposit is related to A-type granite. Tosham ore contains zinc-bearing biotites that coexist with chalcopyrite in ore bodies but Mount Pleasant ore lacks such biotite. We propose that the difference in elemental abundance between the two deposits are caused by the different character of source magma and different mineral associations of the ore body.

Jan 1, 1995

The Central Extended Orebody is located within the Cracow Goldfield approximately 360 km northwest of Brisbane and approximately 220 km west of Bundaberg. It is an epithermal gold deposit hosted by the Late Carboniferous to Early Permian Camboon Andesite. The lode was mined by open cut methods and produced 170 458 tonnes of ore at 5.62 g/t gold.The geology of the rit is relatively simple, comprising two rock types, trachyandesite and rhyolite which have been sub-divided into several units. The trachyandesite is sub-divided into three rock types: brecciated trachyandesite which is the most widespread, hydraulically fractured trachyandesite hosts the mineralisation and the third sub-unit is chloritised hydraulically fractured trachyandesite and has no associated mineralisation. The mineralisation is confined to quartz veins in hydraulically fractured trachyandesite. Several phases of brecciation and subsequent quartz and quartz/adularia vein injection are evident although not all phases are mineralised. Two rhyolite dykes intrude the trachyandesite one is monolithic, the other is sub-divided into hydraulically fractured rhyolite (barren), silicified rhyolite and auto-brecciated rhyolite.

Jan 1, 1993

By Nguyen V. V

The development of structural defects in the overburden material immediately behind a production blast was studied using surface and subsurface techniques. A significant increase in vertical and horizontal fracture intensity was recorded. The extent of fracturing into the highwall appeared to be dependent on the structural and petrologic characteristics of the various lithological units and the relative position of the explosive charges. A shallow zone of disruption to a depth of 10 m and extending to around 30 m from the newly formed highwall crest was recorded. Horizontal fractures in lower units of the overburden sequence were recorded at distances up to 50 m from the new highwall Face.

Jan 1, 1981

By Robinson WB

An accurate and rapid assessment of coal resources, such as that provided by computer modelling, forms an intergral role in evaluating CSR's coal deposits for future development. An in-house system utilising a number of geological, engineering, costing and financial evaluation routines has been developed for DEC VAX computers. The system is currently being upgraded and enhanced to meet the demands at the various mine sites. Computer modelling of the geology is performed on encoded drillhole information and coal core chemical and physical analyses. A conceptual mine plan is formulated then digitized and superimposed on the geological model. Insitu and product coal reserves and qualities as well as overburden and parting quantities are then calculated for each strip or block. These strip parameters are then transferred to the mine scheduling routines to determine the most efficient mining sequence for the mine plan. Cost factors and scheduling data for equipment specified in the conceptual mine plan are used in the mine costing subsystem. The financial subsystem then evaluates the likely return on investment. Future enhancements to the system include improvements in the response time through the introduction of interactive graphics, the direct interfacing of geophysical and analytical data, and further development of a geotechnical'database.

Jan 1, 1983

By Boyling A

United Collieries Pty Limited is an Australian mining company operating one underground coal mine, United Colliery at Warkworth in the Hunter Valley district of New South Wales. Centrally positioned, United Colliery is adjoined by other coal mining operations and is located 80km north - west of Newcastle and 20 kilometres south - west of Singleton. (Fig. 1) High standard road and rail links provide ready access to customers and suppliers.

Jan 1, 1998

The investigations of the Leningrad ruining lilstitute on this problem are carrying out in the following main directions: 1) The analysis and study of contaminants migration at particular sites of mining development; 2) The working out of theoretical and me- thodical basic principles of aquifers migration tests; 3) The work- ing out of methods of the forcasting of groundwater pollution pro- cesses; 4) The theoretical and uethodical substantiation of hydro- geological observations of groundwater pollution processes; 5) The wort ing out of the measures at the groundwater control and their rational use at the particular sites of mining development. The research that have been carried out by the present moment have covered the wide range of wining and geological conditions -- as from the point of view of specific genetic types of water-be- aring rocks (porous, fissured and fissured-porous), as well as from the point of view of pollution sources (surface waste water basins and underground basins of non-standard water) and the cha- racter of the latter's migration (tracers, physically neutral ef- fluents, heavy or light ones). The combination of specialized mi- gration tests and observations carryed out at uoayi, sites, as well as the following ar~,alysis o:i the data of field study allowed to get useful theoretical, methodical and practical results on the all directions above mentioned, ns the summing up of these results the author proposed the concept of controlled ground :ester polluti on. This conception is based on three whales" - groundwater self- purification, engineering prevention measures and ground-water monitoring correlated with each other by succes i.vely refined (ac- cording to the observation data) hydrogeologicZl forecasts.

Jan 1, 1988

By Nilmani M, Fountain CR

Injection of gases into slag-melt mixtures produces various zones as a result of bubble formation and disintegration within the melt. The extent of these zones depends on the type of reactor used. When compared with ferrous processes, non ferrous processes are character- ised by large bubbles formed adjacent to the tuyeres, low flowrates and shallow tuyere sub- mergence. These features can result in a greater proportion of reaction occurring above the bath, more refractory wear and tuyere blockage with more splashing. The large bubble zone adjacent to the tuyeres has been investigated using the tech- niques of physical modelling, mathematical modelling and plant trials. Large bubble form- ation in physical models was recorded using a high speed camera and a rapid response pressure transducer coupled to an oscilloscope and data recorder. It was found that the bubble volume (Vb) could be correlated at low flowrates using the single bubble model Vb = 1.378 Q6/5 g-3/5 Deviations from this correlation occurred with increasing gas jet momentum. Plant trials were carried out on a copper converter at Mount Isa Mines during five different charges. Pressure measurements were made through the tuyeres during the slag blow and commencement of the copper blow. The power spectrum density showed that the dominant pulse amplitude occurred at a frequency of approximately 3 pulses/sec. Plant data from this and other converters were correlated using the same relationship as for physical modelling. De- viations occurred due to the state of the re- fractory, bath composition or bath circulation effects.

Jan 1, 1984

By Yaroshenko YuG, Bokovikov BA, Gordon YaM

Problems of the effect of the number of tuyeres and their parameters on the uni- formity of gas distribution are invest- igated with the use of the authors' devel- oped mathematical model of the movement of gases and materials in the blast furnace. It is shown that the improvement of uni- formity of gas distribution with an increase in the number of tuyeres has a damping character. An analysis of the errors of the specified assumptions of the hypothesis concerning the potentiality of the gas movement in the bed is carried out. It is established that the potential approach model gives good results with the determination of the discharge of gas and its stress field, but is not useful for the calculation of local velocities of gas in the raceway. The results of trials of calculation investigations of the dynamics of form- ation of the raceway and the voidageòfield in beds of burden materials are presented in the concluding part of the paper.

Jan 1, 1981

By M Denton, M Rheinlander, S Mundell, M Broadgate

The manufacturing industry reinvented its approach to the manufacturing process by managing and measuring it end-to-end. This improved returns on production assets, improved information quality and reduced delivery time, resulting in larger net profits through cost reduction and improved cash flow. Today this approach is standard in the manufacturing industry. Resource development has many requirements in common with the manufacturing production line. These include: control of the various steps, transparency of the state of the process to various levels of the organisation and the overall efficiency with which the process is executed. The authors argue that the introduction of manufacturing execution systems (MES) concepts and technologies to resource development processes will lead to similar improvements in control, transparency and efficiency and could improve profitability and enable staff to work more effectively and make better decisions.

Jan 1, 2009

The Engineering Chemistry Division of the Government Chemical Laboratories of WA initiated an ongoing investigation into the possible utilisation of diatomites of this State. The work has shown that local diatomites can be beneficiated by hydro or pneumatic cyc- lone separator circuitry and that the better quality head materials can be upgraded by straight and flux calcination and associated processing to the equivalent of premium grade imported products. Western Australian diatomites vary con- siderably in quality, and the degree to which they can be upgraded and the yield of useful product are influenced by the proportion of impurities and the size, type, and degree of fragmentation of contained diatoms. Conseq- uently careful assessment of ore deposits will be necessary in order to relate ore reserves to planned production. The viability of commercial production from Western Australian resources would hinge on the establishment of markets - largely ex- port - capable of supporting a production level of the order of 30,000 tonnes per annum.

Jan 1, 1979

By Reid A. F

Since early 1971 Western Titanium N.L. has been operating an ilmenite upgrading plant on a commercial basis at Capel, Western Australia. In their process ilmenite is pre- oxidized, then reduced in a rotary kiln to a mixture of metallic iron and titanium oxides. The iron is leached out by accelerated rusting in aerated water, leaving a product with titanium content, expressed as Ti02, of about 92%. Samples from different stages of the up- grading process, representing operations over the last two years, have been studied in detail by X-ray diffraction methods, and the sequences of phases and reactions occurring have been determined. Quantitative X-ray studies showed the ilmenite feed materials to consist of a mixture of ilmenite and pseudo- rutile. Pre-oxidation of the ilmenite at =1000¦C leads to the formation of rutile plus a Fe2TiO5-FeTi205-Mn2TiO5 solid solution. The final reduction product consisted of a mixture of metallic iron, reduced rutile and a FeTi05-MnTi205-Ti305 solid solution. The relative amounts of these reduction products were very sensitive to the initial concentra- tions of the minor constituents manganese and magnesium. The effects of variation of ilmenite feed rate, reducing atmosphere,- reduction temperature and controlled addition of magnesium were also studied.

Jan 1, 1973

This paper investigates dry drilling as a feasible alternative to meet current requirements for improvements in mining productivity in an increasingly competitive world.A field test program was conducted in the surface facilities of a hard rock mine in Sudbury, Canada, to investigate the potential use of dry drilling in underground bulk mining as a conceivably faster and more economical method than wet drilling. The test work consisted of the monitoring of advance rates and bit life while a series of 165 mm diameter holes, wet and dry, were drilled with compressed air at both mine (0.69 MPa) and high (1.72 MPa) pressure levels. The results indicate that penetration rates can be increased by approximately 24 per cent by drilling dry with high air pressure and by approximately 27 per cent by drilling dry with mine air as compared with wet drilling under the same conditions. Dry drilling also has the effect of increasing bit life by up to 69 per cent. An economic analysis for typical hard rock mines indicated that drilling productivity and cost savings can be increased by approximately 23 per cent when dry drilling is utilised.The testing program indicates that dry drilling has the potential to become a feasible technique with regard to performance, productivity and costs.

Jan 1, 1991

By Yianatos J. B

The advances in the study of control alternatives for flotation columns are reviewed. An integral solution to the control problem has to deal with problems associated with instrumentation, process modelling, control strategies and control algorithms. The term hierarchical control is used here to mean the intelligent integration of available knowledge, control algorithms and logic rules of decision. The selection of information, algorithms and rules is based on the experimental and theoretical knowledge of the column flotation process. The software support was designed and implemented in object oriented computer programs. This technique allowed the implementation of a combination of control techniques, algorithmics and heuristics, in the form of a control strategy. This strategy has shown to fit well with processes exhibiting complex dynamic characteristics. The hierarchical control was implemented in a pilot column and included the following general aspects: co-ordination of distributed conventional control loops, use of sets of control parameters for the froth depth control loop according to the froth depth state, verification and diagnosis of sensors, on-line predictive estimation of gas hold-up, diagnosis of common operating problems and the use of predictive control to account for feed flowrate changes.

Jan 1, 1995

By Cox I

Raiseboring is a technique that has become popular in modem mining engineering since the early 1960s. A study has been undertaken at the University of Queensland to determine important factors affecting the optimum diameter of raisebored shafts, excluding local parameters such as the maximwn excavation size that a particular rock type can safely accommodate.This model is used to examine each of these factors and the results indicate that the optimum diameter for raisebored shafts is generally between four and six metres.

Jan 1, 1991

By Bukovinsky SB

The smelting, refining and hydrometallurgical operations practised in the winning of non-ferrous metals are associated with severe aqueous and high temperature corrosion problems.With the increasing costs of maintenenace and the utilization of computerization to control the processes, the trend in recent years has been to spend more capital on improved and proprietory grades of engineering materials, which offer greater reliability and more cost effective plant performance.The problems which have plagued stainless steel users for many years are the alloys' poor performance in chloride or other halide media where pitting, crevice or chloride induced stress corrosion cracking may occur, have been essentially solved by the new proprietory grades. The controlled additions of minor alloying elements including rare earth metals have led to the development of stainless steels with high mechanical strengths, improved corrosion resistance, and high temperature corrosion resistance and structural stability.

Jan 1, 1985

This paper outlines some of the recent developments in Spiral Concentrator design, with particular reference to the range of Reichert spirals supplied by Mineral Deposits Limited, typical applications, and test or operating data, are also provided for the different series of spirals now available.

Jan 1, 1978

Detailed cash flow forecasts have always been almost essential as a basis for judging the viability of proposed new mining projects. In recent years attempts have been made explicitly to take account, in such forecasts, of the uncertainties surrounding the assumptions upon which they are based. With the risk analysis approach, Monte Carlo simulation of the cash flows indicates in probability terms the combined effect of these uncertain basic assumptions. While the use of risk analysis has been widely discussed, few specific applications to real projects have been reported. The application of such an analysis in the feasibility study of the large new Deelkraal gold mine presently being established on the Far West Witwatersrand gold fields by the Gold Fields Group in South Africa is described in the paper. The paper also indicates how one of the major sources of uncertainty, namely the gold content of the ore, can be`quantified in objective probability terms. This feature distinguishes the application fran other published accounts in which only subjective probability assessments have been utilised.

Jan 1, 1977

The lignite mines in the Latrobe Valley of Victoria/Australia have been using continuously operating mining systems for more than 50 years. The relatively small bucket chain dredgers of the early years have been progressively displaced by bucket wheel dredgers with increasing size, increasing capacity and increasing service weight. The large machines for the new open pit Loy Yang have a bucket wheel outreach of 46m, an effective capacity of 3350 bm' coal/h respective 2500 bm' overburden/h and a serv- ice weight of approx. 4500 t. The time between signing of con- tract and starting of operation for these machines is at least four years. The high service weight, the resulting high capital invest- ment and the long period for design, design review, manufac- turing, erection and commissioning of these machines directed the SECV to investigate a possible application of compact dredgers for the Latrobe Valley.

Jan 1, 1989