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Magnetic separation using particle rotation in a continuously rotating magnetic field offers very low to insignificant non-magnetic particle entrapment, and precise magnetic fractions. The precision of rotating magnetic field separations makes the method ideal for dry laboratory magnetic analysis work, where conventional laboratory magnetic separators can give misleading or uncertain data. The very low entrapment characteristics make the method ideal for entrapment-critical separations within the diamond exploration industry or in gold recovery. A single wet rotating magnetic field (RMF) unit is able to achieve a cleaner separation (at similar or better recovery rates) than a three-stage separation using conventional wet drum separators. The RMF separator is able to work effectively at particle sizes below 50 ¦m, and RMF separation could, at least in theory, be used down to single domain particle sizes. Rotating magnetic field (RMF) separation is carried out by magnetically spinning the particles at frequencies up to 300 Hz. The particle rotation itself may be used to roll the particles out of the separator. At angular velocities of 100 Hz, magnetic flocs are unable to form, and any entrapped particles are energetically expelled. In an RMF separator, the outer drum can be stationary while the inner magnet rotor rotates, allowing, for example, the injection of cleaning water underneath the separating magnetics to help remove small suspended non-magnetic particles.

Jan 1, 2000

This work was instituted to investigate the microscopic structure of brown coals by means of microtome sections cut from them. It was found to be essential to impregnate the coal with some material prior to cutting, because of its powdery and crumbly nature. Of a number of impregnating materials tried, e.g., glycerine gum, gelatine, by far the most satisfactory was paraffin wax. Samples of brown coals for section cutting must be moist. When obtained, they should be put immediately into air-tight tins, and, if they are not to be used for some time, it is desirable to keep them under water containing a small amount of formalin. If the sample is allowed to dry in air, it becomes too hard to be cut. It cannot be softened again even by prolonged soaking in water.PREPARATION OF COALSmall rectangular, blocks were cut from the sample with a chisel and a strong scalpel. The largest block prepared was 3·2 x 2·5 x 0·6 cm. The faces of the block from which sections were to be cut were approximately levelled before treatment. The block was then painted carefully on all sides with two coats of warm aqueous agar, approximately 2 %. This prevented crumbling and breakage of the block during treatment. When the agar was set, the block was placed in water, and all the air removed with a vacuum pump. The water was replaced first by alcohol, then by chloroform, by the usual step transference of a series of liquids, in each of which the block was placed for 24 hours: Ethanol %, 10, 20, 30, 50, 70, 85, 95, 100 (three changes); Ethanol-chloroform, 3: 1, 1: 1, 1 : 3, chloroform pure (three changes) '. The blocks were then embedded in paraffin of melting point 56-58°C. Fresh...

Jan 1, 1947

This paper deals with innovative techniques that have enabled personal computers to be used on the mine site to define, develop and manage an ore body resource, while being aware of the consequences to the environment. The same set of personal computer tools that are used for resource estimation, once the province of expensive workstations, can also be used by geologists, mining engineers, surveyors and environmentalists, in managing the whole mining process, including production, grade control, monthly reconciliation and stockpile management through to tailings the management, mine rehabilitation and the due diligence process of mine closure.

Jan 1, 1996

By Nichol R

- PART A The Hoppers Crossing Pumping Station is one of the principal components of the Western Trunk Sewer Project which replaces the 90 year old Main Outfall Sewer and will convey 60% of Melbourne's sewage flow from Brooklyn to the Board's Farm at

Jan 1, 1987

The Hellyer deposit, hosted in the Cambrian Mt Read Volcanics, displays features typical of volcanogenic massive sulphide orebodies. These include a well developed stringer zone, metal zonation within the orebody, a polymict volcaniclastic sequence flanking the deposit and a hangingwall alteration plume in overlying basaltic pillow laves.Mapping and core logging is very detailed in order to extract as much data as possible from the deposit and its host rocks. A geological log suitable for direct computer input was adopted shortly after the deposit's discovery.

Jan 1, 1990

By Arit I, Adisoma G

General Limit Equilibrium Method (GLE) and Janbu's Generalised Procedure of Slices (GPS) are two limit equilibrium methods in slope stability analysis which satisfy all equilibrium conditions. Numerical difficulties associated with these metho

Jan 1, 1998

The LeadtZinc Concentrator at Mount lsa treats all the lead-zinc-silver ore from the Mount Isa Mine and some of the ore from the Hilton Mine. This concentrator was commissioned in June 1966 and total lead-zinc-silver ore treatment was transferred from the Mount rsa's original No 1 Concentrator in May 1967. Plant capacity is around 5 x 106 t/y.There have been three phases of major plant modifications since commissioning:1. replacement and upgrading of the flotation section in 1979; 2. upgrading of the crushing plant and installation of a heavy medium hydrocyclone plant in 1983 for ore preconcentration, and; 3. doubling ball milling capacity and a further upgrading of the flotation section in 1992.Other developments have included the installation of flotation columns and Jameson cells.The evolution of milling practice since 1955 has been reported by Davey and Slaughter (1970), Bartrum, Dobrowolski and Schache (1977), Fiedler and Munro (1984) and Espinosa-Gomez el al (1989).Lead concentrate is smelted in Mount Isa while zinc concentrate and bulk concentrate (locally called Low Grade Middlings or LGM) are railed to Townsville and shipped to custom electrolytic zinc plants and ISP smelters.

Jan 1, 1993

By Amos QG

The Paddington I and proposed Paddington II Pits are both located in what is, by Eastern Goldfields standards, a large tonnage-low grade orebody. The Pits have been designed to supply ore to a substantial Treatment Plant at the designed rate of 875,000 tpa. (This throughput is currently being increased to 1,200,000 tpa).Generally the orebody lends itself to large tonnage mining techniques, relying on only a relatively small amount of sampling. The surface enrichment zone and depleted zone are reasonably complex and require more intensive grade control and sampling techniques as typically utilised in many surface mines in the Eastern Goldfields, although as experience and understanding of the nature of the orebody was gained, less sampling became necessary.

Jan 1, 1986

By Stokes WPC

The capital requirements to develop a new mining venture are becoming very large; amounts of the order of US$1,000 million are not now unusual among estimates to bring new mining complexes into production. At the same time prevailing political and economic conditions are making it increasingly difficult to determine whether or not a project is likely to be viable. These factors emphasise the need to carry out thorough evaluation studies of all mineral prospects before making major investment. Additionally with the rapidly changing economic climate existing at the present time, it is becoming more and more necessary to carry out reappraisals of existing mines. An important function of both initial evaluations and reappraisals is to provide the operators of the mine with effective mining plans to ensure that the operation will meet its required economic targets. P, p M. tl p b, c v, s c 1 n 1 f r d c e c e u w Modern computers are well equipped to store and manipulate large amounts of data with speed and reliability. Their use in the mining field r is increasing and this trend serves to free f technical staff from much of the time consuming m and error prone hand calculations which were o formerly required in determining reserves and w carrying out all forms of mine planning. r Nevertheless, computers are not a universal

Jan 1, 1980

By M Littlefair, D Gribble, R Rounsley, I Te

Low-density explosives (LDE) have applications where the explosive properties of ANFO are not well matched to the rock. In particular, rocks that are of low strength and/or well fragmented in situ. Dyno Nobel Asia Pacific (DNAP) has developed a new LDE, BlastLiteTM, which can be used as a cost-effective replacement for ANFO with excellent detonation characteristics. The product is based on ANFO with the addition of a bulking agent. The key to the product lies in the ability of the bulking agent to form a homogeneous blend with ANFO without the need for any emulsion matrix to bind the product together. This results in an LDE of low cost and high weight strength compared to existing commercial LDE products. The product has been trialled extensively and has proven to provide results that are equivalent to, and often better than, ANFO with reduced powder factors. This paper details the laboratory development and results of field trials for DNAPÆs LDE solution: BlastLite.

Jan 1, 2004

Digital computers, by virtue of their capacity for high speed repetitive calculation at low cost, are finding increasing application to routine calcula- tions in the mining industry. In this paper techniques are shown whereby the use of computers can be extended to more complex tasks. The regular calculation of grades and tonnages of material to be extracted from specified areas of an operating open pit is a necessary part of production planning. In this paper it is shown how these calculations can be carried out by computer. thereby freeing planning staff from manual calculation. An operating open-pit mine can be described in terms of drill logs, geological ore boundaries and pit perimeters at various levels. These form the data base which must be suitable for frequent updating to incorporate new information. A suite of computer programmes is described which operates on this data base to calculate tonnages and grades of ore within extensions to the perimeters as indicated to the system by planning staff. Possible future extensions are discussed.

Jan 1, 1971

By D J. D'Astoli, M D. Goodz

In 1993 a detailed review of drill sample yuuluy was rouxluard through twin and triplet drill holes using open hole, crossover suhreverse circulation (RC) and diamond drill methods. Advances in face-sampling RC methods demanded a further review of the validity and reproducibility of drill sample data. A program was undertaken to drill three RC holes using the latest technology (new face- sampling bits, dust suppressers, cyclones and compressors). Volumetric and mass studies were undertaken to review sample recoveries. Modal analyses on indicator minerals were logged to interpret the relative degree of mineralisation. Ambiguities in the results were immediately apparent and the consensus was for follow-up twin diamond holes using HQ3 coring tubes. The most mineralised RC hole was selected for the first twin diamond hole. This RC hole (MS 313) encountered one intersection of >0.47 g/t; in contrast the diamond hole (MS 342) had nine intersections at > I g/t. Results at hand show definitively that face-sampling RC drilling is not acceptable as a method of exploration for gold deposits of the Woods Point type. Furthermore it is demonstrated that RC drilling should not be used for any type of exploration of high-grade gold vein deposits related to highly fractured or porous hostrock, or areas of previous mining activity. Methods are proposed for reviewing of rates of sample recovery, distribution and cross-contamination. Comparisons also show that in limited metreage reconnaissance drill programs, diamond drilling is more similar to percussion in per metre costs, than it is credited with, and always provides more bang for the Buck.

Jan 1, 1997

By Elliot B. J

Flash smelting is a complex and capital intensive technology. Although in use for 50 years the technology is still not well understood from a fundamental point of view and thus uncertainty is evident when significant change to the practice is necessitated. The application of effective design and process simulation tools has significant advantages when process change and improvement is required. Mathematical models have been used to simulate the processes occurring in the shafts of copper flash smelters. The present approach to flash furnace modelling differs from earlier work in that the burners were modelled in detail, the output from the burner model becoming the input to the shaft model. This paper serves as an introduction to the modelling process used to analyse the performance and provide a better understanding of the parameters applicable to the flash furnace at the Kalgoorlie Nickel Smelter.

Jan 1, 1992

A system for rapid on-line determination of weight percentage coal in slurry and weight percentage ash in coal has been developed at the Julius Kruttschnitt Mineral Research Centre, University of Queensland. The gauging system is suitable for use with coal flotation slurries or slurries having a maximum particle size of about 1 millimeter. The system is based upon measurement of gamma ray transmission; radioisotope sources emitting photons of two widely different energies are employed. The inaccuracies of measurement that would normally result from variable amounts of air entrained in the slurry are substantially reduced by pressurising the slurry to approximately 2MPa (300 psi) using a Mono pump. The equipment can be used to make measurements on more than one slurry stream by pumping streams sequent- ially. The system is being tested at the Peak Downs Mine of the Utah Development Company in Central Queensland. This paper describes the theoretical principles of the gauge design, the experience gained to date in the commissioning of the equipment, including the installation of a PDP 11/03 computer, and the progress made in developing satisfactory interpretations of the gauge count-rate output.

Jan 1, 1978

The calibrated thermal IR data of part of Cambay Basin is used to determine surface temperatures and to detect the heat flow. Applying the conductive heat flow continuation technique, the three dimensional configuration of the hydrocarbon bearing reservoir was defined. The zone delineated by the present study coincides with the oil-bearing structures inferred by seismic survey. The results indicate the possibility of the technique as an effective tool in hydrocarbon exploration.

Jan 1, 1986

By Hoppe AJ

Drilling and shooting techniques at Moura open-cut have evolved over a period of 16 years and are the result of hard earned experience combined with established practices and consul- tation with professional services. The wide range of overburden types encoun- ted in the field requires varying methods to achieve the best results at all times. Safe working conditions for the employees and protection of mining equipment is of para- mount importance and close liaison is maintain- ed with the Department of Mines Queensland to keep abreast with changing legislation. Drill patterns, charging profiles, types of explosives and ultimate results are des- cribed in detail along with a resume of equip- ment. Costs of drilling, labour and explosives are also analysed with a total of approximately 20c per cubic metre of shot ground. Future developments and improvements to facilities are also outlined.

Jan 1, 1978

By Drain P, Dibdin T. R

THE completion of the Linda incline man and supply haft at the Mount Morgan Gold Mining Oompany's mine led to an investigation of the various safety gears in general use in mining shafts. One of these gears completely fulfilled the necessaryconditions. This paper endeavours to give a description of the man car and safety gears now operating in the before mentioned shaft, together with the main considerations leading to their design and sub equent adoption. Fig 1 diagramatically shows a longitudinal section of this shaft.

Jan 1, 1911

By Gole MJ

The Goodyear nickel prospect is located 45 km southeast of Kalgoorlie (31.04¦S, 121.80¦E) near the eastern boundary of Hampton Area - East Location 45 (Figure 1). Nickel mineralisation was discovered on the Goodyear prospect in March 1996 when a reverse circulation drillhole (GYC5), initially drilled in December 1995, was deepened to meet a minimum footwall penetration requirement of 20 in that had been set for the drill program. Approximately 3 in of sulphides averaging 4.9 per cent nickel was intersected from 296 metres down-hole, this being within 2 in of the first end-of-hole. Hole GYC5 was part of an eight hole drilling program undertaken by Titan Resources in late-1995. This program was designed to test whether nickel mineralisation in the Dunlop prospect, discovered by the Western Mining Corporation - BHP Camylia Joint Venture immediately east of the East Location 45 boundary, continued across the tenement boundary. The area targeted by the initial drill program had been explored by Western Mining Corporation in the mid-1980s using extensive surface sampling and a drilling program that included 17 RAB and percussion drillholes. None of these holes intersected nickel Mineralisation.\

Jan 1, 1996

By Mortimer RR

The Weipa bauxite mining operation on the west coast of Cape York currently mines lb million tonnes of crude ore per year from the Andoom and Weipa mines. Andoom ore is trucked up to 4 km to a rail load station and hauled 20 km by train to the Beneficiation Plant. Weipa ore is trucked up to 7 km to the Beneficiation Plant. Increasing haul lengths and production requirements have led to a progression of larger two axle rear dump trucks and currently he intrcducticn of 145-tonne, three axle L t Dm dump trucks. bith the introduction of the Andoom a operation in 1972, the decision was made to use a railway system to haul crude ore from Andoom to Weipa. This system has proved to be successful from both an economical and operational view point. Due to the successful combination of a truck and rail haulage operation in Andoom, future :evelopment of orebodies requiring increased haul distances and increased production tonnages will probably result in extension r>f the railway system to compliment the trucking operation from the mine face.

Jan 1, 1978

Deposition of uranium in the South Alligator river area has been influenced structurally by reverse faulting; and lithologically by carbonaceous shales and sandstones. Mineral assemblages suggest a mesothermal-epithermal epigenetic mode of origin. The ultimate source of the uranium and associated metals is probably in deep seated magmatism which is expressed at surface in the widespread penecontemporaneous vulcanity.

Jan 1, 1968