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By Behl S

Flocculation behaviour of six different dolomite samples, four from the Florida mining district, one from Perry, South Georgia and another from New Jersey was examined using polyethylene oxide (PEO) as a flocculant. The samples were similar in chemical composition, however the porosity of the samples from the Florida mining district was higher than the others. FT-IR, adsorption and surface modification by leaching revealed that flocculation was directly related to the presence of isolated hydroxyl groups on the surface. The adsorption mechanism was believed to be hydrogen bonding of the ether oxygen of PEO with isolated -OH sites on the solid.

Jan 1, 1993

Mt Todd lies towards the south end of the Pine Creek Geosyncline, sandwiched between the Cullen Batholith and the Edith Falls Basin, in an area of regionally metamorphosed sandstones, siltstones and shales. The Batman deposit, some 3 km west of Mt Todd is a sheeted quartz vein system hosted within greywackes of the Palaeoproterozoic Burrell Creek Formation (Finniss River Group). The gold-bearing quartz veins, trending 010¦-020¦ and dipping 60¦-70¦E, are commonly 0.5 to 5 cm wide and occur at intervals which are from 10 cm to 1 m apart. Gold tends to be restricted to the quartz veinlets and immediately adjacent country rock. Grade Control utilises two 4 m 'collar' samples which are collected from each 8 m production blasthole. The irregular distribution of the quartz veins and erratic gold mineralisation has resulted in a disseminated 'salt and pepper' type of gold occurrence, with only a poorly defined footwall. Delineation of ore and waste blocks for mining uses an approach which combines the smoothing effect of kriging with a pragmatic view of the raw data. Large ore blocks with simple geometry help to minimise mining dilution, reduce block variance and give good reconciliations to interpreted ore tonnes and grade. Daily mine face advance is reported against truck counts and provides continual comparison with budgeted production. All data processing uses Gemcom software, together with Lotus spreadsheets.

Jan 1, 1994

Comminution Kinetics equations are developed to take into account difference of grindability of mineral components. The equations describing both batch and closed circuit grinding or crushing processes are given. These equations are applied to industrial data to derive comminution kinetic and classification characteristics of the component minerals in a multi-mineral ore. Control strategy based on these concepts is presented.

Jan 1, 1985

By White A, Price G

The main assets of a mining company are its orebodies; the second are the people who find and use them.The graphs in Figure 1 were derived from a paper by Rob Macdonald of Rothschild Australia presented to The AusIMM Centenary Conference in Adelaide earlier this year. They show that the value of the industry on the Australian Stock Exchange halved over the past decade, despite the re-investment of capital equivalent to its full market capitalisation. Why is this so? The average dividend yields for the ASX Mining Index was never above five per cent during that period and barely averaged 2.5 per cent. Why then is $Ai million capital re-investment per employee since 1960 not enough to generate a rate of return to investors better than lousy bank interest? Do the investing public no longer regard our industry's assets to be world class?

Jan 1, 1993

By Boger D. V

Two industrial case studies in which detailed investigation of the flow behaviour of mineral slurries is used to assess the feasibility of pipeline solid transport are described. The first example deals with the pumping of highly concentrated bauxite tailings to disposal, while the second exam- ple examines the possibility of transporting high-density Victorian brown coal slurries which previously has been thought as uneconomical. It is demonstrated that these typical solid handling problems can be solved by a good understanding of the rheology of suspensions.

Jan 1, 1989

In 1972, with the West Lyell Open Pit winding down, mining operations transferred underground. All development tunnelling until the end of the decade was carried out by a fleet of ten pneumatic Jumbos.A decision was made in 1980 to purchase an electric-hydraulic Jumbo and a second was purchased in 1982. Their introduction changed the face of development at Mount Lyell. Significant new demands were placed on main-tenance sections, particularly on electrical reticulation.Subsequently, two further electric-hydraulic Jumbos were purchased from Agnew Mining in 1984, and successfully overhauled and commissioned. As well, two electric-nydraulic production drilling rigs have been purchased. Only one of the original pneumatic Jumbos remains in service.

Jan 1, 1985

By Ibaragi K

High grade ores were intersected in 1981 by a scout drill carried out by the Metal Mining Agency of Japan during a reconnaissance dril ling programme. The original aim of the hole was to explore a deep target where geophysical anczralies overlapped the abandoned old drifts (gravity- high, resistivity-low by airborne EM, and resistivity-low near the surface and high at depth by Schlumberger deep sounding). Subsequently, a follow-up drilling programm was commenced by the Sumitcrro Metal Mining Co Ltd, and all the 18 holes intersected high grade ores. The resources were then "guestimated" to contain ca.120 tonnes gold with an average grade of 80g/t Au between -40m and +120n a.s.l. The underground development was started in December 1982 and the first crosscut intersected the ore body at 100m level (a.s.l.) in July 1985.

Jan 1, 1987

The mineral pulp as it passes through grinding-classification, flotation and solid-liquid separation is examined in the context of it being a particulate fluid. By focussing on the complex viscosity and yield stress of the fluid, new control strategies are discussed. The mineral-particulate fluid is dominatred by non-Newtonian rheology (ie shear thinning, shear thickening, shear yield stress and compressive yield strength). The control of this Theology is seen to be dependent on the fundamental practice-particle interaction forces and with adequate information, it is possible to use the complex shear properties to advantage. The advantages, in terms of final waste and concentrate management, to high weight per cent solids in the mineral particulate fluid, are explored and control strategies outlined.

Jan 1, 1993

As part of its Concentrator operation Hamersley Iron Pty. Limited uses wet high intensity magnetic separation to upgrade shaley low grade ore in the minus 0.5mm size range. Materials handling problems, largely caused by fine ore types and design deficiencies, surfaced in the Fines Treatment Plant soon after Concentrator commissioning in 1979. Surging throughout the circuit impaired process efficiency and added to problems caused by capacity and process control limitations. In 1981 extensive modification works were initiated to supplement minor changes made to that date. The new circuit significantly increases capacity and provides greater process control.

Jan 1, 1978

By Nott M. C

The oxidation of xanthate collectors to xanthate/dixanthogen results in a higher hydrophobicity of sulphide minerals surfaces due to the action of dixanthogen. This higher hydrophobicity can be proved on a fundamental level by examining the st

Jan 1, 1994

By Fabjanczyk M. W

A limitation to present theoretical roof reinforcement design methods is the inability to derive accurate and quantitative information about the roof rock condition and the action of reinforcement at various excavation stages. To obtain the information required to assess roof rock stability, detailed monitoring of the in-situ behaviour of reinforcement and roof strata is required. Reliable instru- mentation and techniques have been developed for use in underground coal mines to identify the geometry and magnitude of displacements occurring in roof rock and the forces generated in reinforcement. The use of such instrumentation allows an accurate assessment of the in-situ capability of reinforcement and the mode of reinforcing action developed. In-situ monitoring can supply data required for the practical design of reinforce- ment and assess the potential stability of current designs. The use of such data together with mine wide appraisal of rock and stressfield considerations, can allow roof reinforcement to be designed on the basis of a predicted roof Response.

Jan 1, 1986

By Gupta A, Fung C. C

The hydrocyclone parameter d5Oc is estimated by the application of Artificial Neural Network (ANN). Results indicate that ANN performs equally well as compared to statically derived analytical formulae. Results also show that ANN will also be convenient in the on-line control of hydrocyclones.

Jan 1, 1996

By Thornton D, Firth B, Kojovic T, Brien G, O&apos

Coal fragmentation is a function of coal type and mining process. Each unit step in the mining, handling and crushing chain of coal imparts energy to the material and impacts on size degradation and consequent mineral matter liberation and pla

Jan 1, 1998

The paper presents the results of laboratory blasting and grinding experiments on a low-grade iron ore, investigating how blasting will influence the subsequent crushing and grinding operations. Increased blasting energy will lead to a reducti

Jan 1, 1998

By Waghorn EP, Gleeson HB

The Loy Yang Optr, Cut is a brown coal mine bring developed in the Latrobe Valley region located some 160 kin south-east of Melbourne, Victoria. The mine has been designed to supply a mine mouth power station at a rate that will rise to 32 million tonnes per year by the mid 1990's. Continuous mining metnuds are employed using bucket Whtel excav- ators and conveyors. This paper describes the basis of the design of the Loy Yang continuous mining system ano cne experience of four years of initial operation.

Jan 1, 1987

Western Mining Corporation, managing partner of the Windarra Nickel Project are in- stalling a raise-bored haulage shaft and under- ground crushing system at the Mt. Windarra Nickel Mine. The system will be the second of its type installed by W.M.C., the first being in- stalled at the Otter-Juan mine in Kambalda in 1976/77. Both haulage systems became necessary as a result of the increasing production limi- tations, and escalating costs of a deep decline mine. The Windarra haulage system required a single 3m diameter vertical raise drill hole to a depth of 470 metres. Two five tonne skips in balance will hoist crushed ore and mullock to the surface, at a design rate of 200 tonnes per hour, effectively reducing truck haulage leads by up to 50%. It is expected the project will be in full operation by mid 1982 and will enable the mine to achieve an annual production rate of 600,000 t.p.a. by 1983.

Jan 1, 1982

The paper reviews some characteristic features of feasibility studies and discusses the need for a wide scope at the pre-feasibility stage. The performance of recent Australian gold mines against the predictions contained in their respective feasibility studies is examined, resulting in a recommendation that feasibility studies need to be improved The advantages to be gained from having a feasibility study reviewed by an independent authority are discussed, and some of the reasons for using consultants are listed. Two examples of successful optimisations in the early stages of pre-development studies are described briefly and the benefits achieved are presented. The paper concludes that feasibility studies need improvement to enhance the confidence of investors in the mining industry.

Jan 1, 1991

By Swift J. D

A key parameter affecting the performance of gravity thickeners in hydrometallurgical processing operations is the aggregation state of the feed after the addition of a flocculant. New procedures which measure the settling ratelsize relationship and the size distribution of aggregates in their process liquors have been used to quantify the aggregation state of the feedwell, overflow and underflow streams in a tailings thickener. The data obtained have been related to the thickener's operation and to a change in the flocculant dosage. A comparison is also made between the settling rate/size relationships determined with these new procedures and the mud-line settling rates from cylinder tests.

Jan 1, 1991

By Pala J

The Ellalong Colliery has been the first to mine the Greta Seam using the longwall method. Analysis of data from geotechnical monitoring has pointed to the role of the strong, massive sandstones of the Branxton formation in the development of loads on the powered supports and pillars. Failure of the sandstone intermediate-roof has been related to first-weight and periodic weighting, measured on the supports, using simple "voussior" analysis. Stress changes, including triaxial components measured in the barrier and chain pillars, have been compared with 2- and 3- dimensional numerical models. The applicable range of the models for the prediction of pillar loads under the strong roof is discussed.

Jan 1, 1986

Rifting and transfer faulting in the Late Cretaceous to Early Tertiary resulted in the formation of the Bundaberg Trough and Wallaville Basin and deflected the margin of the Maryborough Basin southwestward between the Kolan and Burnett Rivers. During the Cainozoic, three periods of volcanic activity occurred in the Bundaberg-Gin Gin area. The oldest of these periods, Paleocene to Early Eocene, resulted in the outpouring of tholeiitic lavas. During the Late Miocene to Pliocene, undersaturated alkali basalts generated at depths of from ca. 35 to 55 km were emplaced. These lavas were followed in the Pleistocene by the alkaline Hummock and Berrembea Basalts. The loci of eruption of all of these lavas were controlled by the intersection of the transfer fault system and pre-existing north to northwesterly trending faults in the Bundaberg-Gin Gin area.

Jan 1, 1990