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By Doyle R

Underground operations commenced at Tower Colliery in late 1978 and the early prevailing mining conditions in the worked seam were considered poor as a result of high stress and geological disturbances. This suggested that outbursting activity may be a possibility. The colliery has since recorded a total of 13 individual outburst incidents, all of which have been associated with the same dyke and strike-slip fault zone. This paper depicts the geological conditions and presents the results of investigations undertaken at the time of these outbursts.

Jan 1, 1986

The screening of iron ores, sinter and coke, and investigations undertaken to improve screening efficiency and cloth life are discussed. The major modifications to coke screening proposed with the construction of No. 7 coke ovens battery are briefly described. The major problem areas were identified as screen cloth blinding and pegging, feed presentation and screen overloading. Blinding and pegging have had a significant effect upon screening efficiency with the screening of sinter, coke breeze and wet iron ores in particular. Pegging can be reduced or eliminated by the correct selection of aperture size and shape, screen excitation and slope, and screening medium. Blinding encountered with wet coke breeze was a particular problem in which no significant progress was made.

Jan 1, 1984

The first mining in Western Australia probably commenced some 40 000 years ago when Aborigines arrived and began quarrying stone for tools and weapons, and ochre for decoration. The earliest documented mining by European settlers took place in 1850 on a small lead vein in the bed of the Murchison River, reported by the explorer A C Gregory. However, it was the discovery of gold in the Kimberley region in 1885 that first drew wider attention to the State's mineral potential.

Jan 1, 1992

By J-P Franzidis, M Esvelt, E V. Manla

The Floatability Characterisation Test Rig (FCTR) is a self-contained, highly instrumented, mobile pilot plant that is able to treat up to 2 tph solids. It consists of a bank of six 130 L WEMCO« SmartCells« and a bank of six 50 L WEMCO« SmartCells«. It was developed as part of the AMIRA P9 Project, primarily to determine ore floatability characteristics and to develop and validate flotation plant modelling, scale-up and simulation methodologies. However, it may also be used to carry out pilot-scale flotation test work. This paper briefly describes the circuit modelling, simulation and scale-up test work performed using the FCTR and the use of the FCTR in pilot-plant test work performed by the metallurgical staff at WMCÆs Kambalda Nickel Operations and Mount Keith Nickel Operation. At both Kambalda and Mount Keith the FCTR was found to be very flexible and straightforward to run, with an easily changeable circuit configuration and stable operation. Testwork was facilitated through having full stream sampling on all streams, and a high degree of instrumentation providing accurate measurement of process variables. The results obtained from the FCTR testwork were highly repeatable. As a consequence of using the FCTR, WMCÆs Kambalda Operation and Mt Keith Operation were able to complete a rigorous programme of pilot plant testwork more quickly than in the past, and with a high degree of confidence in the results.

Jan 1, 2003

The blasting process involves a complex interaction of a delayed sequence of moving sources of seismic energy which produce nonlinear behaviour near the blast holes. A deterministic description of this nonlinear behaviour represents a formidable problem. The modelling of blast vibrations remote from the blast source may use some of the primary features of the blast design such as charge type, charge weight and initiation sequence. Such modelling of blast vibrations usually assumes linear behaviour remote from the blast holes. Site specific charge weight scaling laws may be used to predict the blast vibration levels with relatively poor accuracy. An important ingredient which is missing from charge weight scaling laws is the seismic source wavelet emanating from each blast hole. The present paper considers some approaches which may be used to determine a suitable source wavelet. The wavelets are suitable for use in the region where linearity may be assumed. In that region, it is possible to model the attenuation and scattering of the seismic wave as it propagates from the blast source to the measurement location.

Jan 1, 1990

By Woodhouse M, Drew GJ, Andrews DL

The Honeymoon nickel sulphide deposits are located 45 km south of Wiluna in the 2.7 Ga old Agnew-Wiluna greenstone belt in the NE of the Yilgarn Craton (Figure 1). Both disseminated and massive nickel sulphide deposits are present within the deformed and metamorphosed Honeymoon Well ultramafic complex and are hosted by distinctly different komatiitic lithologies (Gole et al, 1996). The deposit styles and host rock lithologies reflect formation in markedly different volcanic settings. Metasomatism has affected parts of the ultramafic complex, including sections of the sulphide deposits, and has had a marked impact on mineralogy and bulk sulphide compositions. The present indicated resource is 158 Mt at 0.71 per cent Ni in four deposits (0.4 per cent Ni cut-off, resources above 300 m depth, December 1995). This includes a massive sulphide resource of 2.5 Mt at 3.36 per cent Ni.

Jan 1, 1996

A 1991 survey of 48 mining companies, employing more than 24 000 employees, showed that disabling injury and disease rates continue to be the most common measurements of safety management effectivness in the Australian mining industry.Of the companies surveyed, 22 claimed to be making regular safety audits. Of these only two listed the improvement of audit scores among their goals for 1991.Influenced by loss control management thinking, some managers have expanded the scope of their safety programs to include all accidental operational losses adversely affecting mine profitability.Learning from their new experience with total quality management some managers are now recognising that successful safety management outcomes depend on the effective management of program inputs. They are thus turning away from measurements of accident consequences - the failures of the management system - to measurements of management control.The new focus of safety management attention is now on corrective actions before accidents happen.

Jan 1, 1992

Methods for ore reserve estimation are classified. The amount of information needed to asses ore reserves is analysed. Reference is made to gold sampling. Consideration is given to nugget effects and ore reserve estimation procedures where they are significant. Computer methods are discussed

Jan 1, 1997

Studies of Theological effects in grinding hold promise for improving this energy-intensive process. Six surveys of the Hellyer ball mill were conducted. The stream and sizing data from these surveys were balanced by JKMbal to compare the mill

Jan 1, 1994

A review is given of progress made to- wards the development of personal gravimetric dust sampling for risk assessment on South African gold mines. The present strategy is critically examined on the basis of principles for assessing health hazard from dust exposure. Reasons are advanced for replacing the konimeter with a gravimetric system based on full shift personal sampling. Constraints imposed by local characteristics of gold mines are used to illustrate the difficulty in finding suitable instrumentation for measuring personal exposure to respirable silica.

Jan 1, 1988

The economic significance of a fundamental understanding of the mineral pyrrhotite is dis- cussed. Particular emphasis is placed on the relationship of other sulphide minerals to the pyrrhotite when it is the major sulphide mineral present in an ore body. Studies of the Kambalda nickel deposit are used to give a better under- standing of (a) the genesis and other character- istics of a particular ore body (b) the textural relationships between pyrrhotite and other sul- phide minerals (c) magnetic properties of natural pyrrhotite, and (e) the oxidation and supergene processes that take place in a sulphide ore body.

Jan 1, 1972

By Beattie T. A

The ability of explosives to fragment rock has been assessed in small scale trials at the Granite Rock quarry, Baimsdale, Victoria. Three 65 mm diameter holes were fired simultaneously in a five metre bench, and the rock collected, screened and weighed. The mass of fines increased as the explosive strength increased in the series 30(10 ANFOPS

Jan 1, 1990

By Carter NB

A statistically-designed experimental program has been used to study compositional and processing variables which influence the development of strength and reducibility of iron ore pellets. The effects of chemical composition and processing variables were investigated by indurating laboratory-made green pellets, of known composition, under approximately isothermal conditions in a pot- grate simulator. Some findings from a six- variable study are summarized in the form of contour diagrams and emphasize the importance of interactions between the variables. Production of strong, highly reducible pellets is possible over a considerable range of combinations of temperature and firing time. Abrasion index (AI) and cold compression strength (CCS) improve as both these variables increase, but reducibility (R) declines, so a compromise is required. When the lime level is too low to form enough slag for bonding, the AI and CCS may be inadequate. Larger additions of lime tend to improve AI and CCS, with only slight effects on R. Finer grinding of the balling feed (i.e. higher Blaine index) tends to improve Al and CCS without

Jan 1, 1980

Pyrrhotite is the predominant gangue mineral at Renison comprising about 60 percent of the sulphides in an average ore blend. It exists as two crystal structures - monoclinic and hexagonal. Monoclinic pyrrhotite is the slowest floating of all minerals but is ferromagnetic and hence recoverable more efficiently by low intensity magnetic wet drum separators than flotation. This paper discusses the installation and commissioning of four 0.915 m x 3.0 m, 0.1 Tesla permanent magnet, wet drum separators prior to sulphide roughing flotation. Planned circuit and process control modifications to better accommodate magnetic separation into Renison's flowsheet will be Discussed.

Jan 1, 1991

By Qi P. H

Gold dissolution can be achieved with a number of complexing ligands, all with varying degrees of stability. Processes based on the use of halogens have been known for many years. Beside providing the necessary complex- ing role, the halogens under the appropriate conditions are very effective oxidants for gold. Of the halogens, the gold iodide complexes are the most stable in aqueous solution. Iodine can establish the desired oxidation poten- tial for oxidizing gold, and unlike chlorine and bromine, the oxidizing potential of iodine is mild enough to avoid the oxidation of impurity constituents like metal sulfides. A series of experiments to investigate the fundamental electrochemistry of gold in different halide solutions was performed. Cyclic voltammograms of gold in the presence of 10-2 M chloride, bromide and iodide, respectively show that for a given potential the rate of oxidation is much faster in iodide solution than in either chloride or bromide. An overlay of linear sweep voltammograms for the anodic oxidation of gold in iodide and the cathodic reduction of iodine species on gold provides an effective method for examining the dissolution of gold in iodideftodine solution. The dissolution rates obtained from both electrochemical and actual leaching results are compared. Optimum leaching conditions are analyzed in terms of the iodide/iodine concentrations. Conceptual processes for the recovery of gold and iodide and the regeneration of iodine are discussed.

Jan 1, 1991

By Mauk JL, Arehart GB

Quartz veins from the Martha Hill epithermal gold-silver deposit, Waihi, commonly exhibit crustiform banded textures. Visual differences observed between bands are primarily the result of a 1 to 1500 ¦m variation in quartz grain size. Quartz band textures are dominated by anhedral interlocking quartz mosaics, commonly associated with minor adularia and sulfide phases; these textures are interpreted to be products of amorphous silica crystallisation. The occurrence of rhombic adularia suggests that prolonged boiling influenced parent fluids. In contrast, the presence of coarsely crystalline bands, made up of subhedral to euhedral quartz grains, infers primary crystal growth from solution; evidenced by the occurrence of growth-zoned quartz within these bands. There is a narrow range of 3.3%o in 618Oq,,,,,= between maximum and minimum isotopic values for the deposit. Significant overlap in 618Oqu,, values are observed between the Martha and Welcome lodes. However, statistically significant and commonly systematic differences do occur between individual bands analysed in most samples. Temperature fluctuations may be the dominant factor responsible for observed inter-band variation.

Jan 1, 1995

By Egan J. R

Changes have recently been applied to the Sullivan Concentrator lead and zinc circuits to treat fine-grained ores which make-up the majority of ore reserves in the mine. Pilot plant testwork conducted in 1990 - 91 indicated that concentrate grades would be substantially improved by reducing the particle size (Pao) of the lead from 38 to 15 ¦m and the zinc from 45 to 24 ¦m. Circuit revisions involved installation of major new equipment including: two 600-kilowatt Vertimills for regrinding, a four metre diametre column flotation cell and a four metre diameter hyperbaric pressure filter for dewatering. Duties of the existing regrind mills were Reassigned.

Jan 1, 1993

The design and operating characteristics of the hydraulic cyclone elutriator were described in detail by Kelsall and McAdam (1963), and the method of operation of the commercially available version, the Cyclosizer, is described in the manufacturer's pamphlet (Anon). Complete details of the operating procedure are given in the relevant operating manual (Anon, 1964).The cyclones which form the basis of the Cyclosizer (Fig. 1) under normal operating conditions produce typical cut sizes of 44, 33, 23, 15, and 10 µm for cyclones one to five respectively for material with a specific gravity of 2·7. At the end of the selected elutriation period each sized fraction is discharged and collected for subsequent assay or analysis but all material rejected by the fifth cyclone (e.g. minus 10 \lm quartz) normally passes to waste. When this material is needed for separate study, although its amount and average analyses can be calculated by difference, it may be necessary to collect more than 250 I. of very dilute suspension, flocculate the solids, allow to settle, and decant off the supernatant liquid.This procedure is cumbersome and inconvenient and the simple technique to be described may offer some advantages. The temperature of the water fed to the Cyclosizer is maintained at a constant value for added reproducibility.PROCEDUREThe present overall treatment of the subsieve material (minus 37 \lm) fed to the Cyclosizer incorporated several refinements compared with normal operation and these may be best illustrated by anactual example. Material to be cyclosized (25 to 100 g depending on size distributIOn and specific gravity) is completely dispersed in water at 23 QC by vigorous stirrmg, using suitable dispersants if necessary, in a...

Jan 1, 1974

By Russell F. M

Following the accident in the Peterson section of Mufulira mine in September, 1970, a method had to be found of extracting up to 300 000 tonnes of ore per month from this area without inducing caving. Sandfill mining methods were chosen, necessitating a plant capable of producing both cemented and uncemented fill on a large scale. The paper covers the design and construction of this sandplant which is thought to be unique for its size, as it incorporates three 3 000 tonne capacity settled storage silos, a 500 tonne capacity cement silo, mixing tanks and a control room situated underground. The plant is designed to handle an aver- age of 440 tonnes per hour with a maximum of 660 tonnes per hour for limited periods, delivering either uncemented fill or cemented fill in proportions varying from 1:6 to 1:30. The instrumentation and equipment necessary to give one man operation of the plant is described and the fill mining methods now in use at Mufulira are briefly outlined.

Jan 1, 1973

By Keyte SG

Gravity methods of recovering alluvial gold are not very efficient at particle sizes below about 0.1mm. Whereas such gold may not have been economic to recover in the past, the same may not be true today. Centrifugal concentrators, like the Knudsen and Knelson bowls, are showing promise after an inauspicious start, at least in New Zealand. The large proportion of heavy mineral in many auriferous beach sands and the natural hydrophobicity of fine gold should make flotation an attractive contender for its recovery. The conventional mechanical flotation cell is effective, but roughing, scavenging and cleaning are necessary to achieve both high recovery and low mass yield. More problematic is the difficulty of maintaining coarse and dense sands in suspension. The air sparged hydrocyclone is effective at recovering fine gold from a fine Colarado River sand, but is not effective for the coarse and dense beach sands of New Zealand. The flotation column shows much promise for these sands, when recoveries of over 80% and mass yields of less than 1% can be achieved in a single pass. The froth separator of the USSR and flash flotation could also be worthy contenders. It is felt that flotation could be limited to naturally and artificially de-slimed concentrates.

Jan 1, 1990