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By B Indraratna, A Dey

The surface geometry of a rock bolt plays a very important role in the rock/resin/bolt load transfer mechanism. Very little work has so far been reported on the influence of the bolt surface geometry on the bolt/resin interface failure mechanism. This paper examines the behaviour of bolt surface roughness under constant normal stiffness condition in the laboratory. To study the shear behaviour of the bolt/resin interface a series of shear tests with an initial normal stress between 0.1 to 7.5 MPa has been conducted on the flattened bolt surface of two most popular bolt types currently being used in Australia. Bolts with deeper ribs offered better shear resistance at low initial normal stress conditions whereas bolts with shallow and closer ribs offered better shear resistance at high normal stress conditions. The maximum dilation occurred at a shear displacement of 60 per cent of the rib spacing irrespective of the bolt type and depth of the rib.

Jan 1, 2000

By Cooper W. C, Stokes M. A

Proterozoic gold deposits in the Pine Creek Geosyncline are at present receiving renewed attention with the opening of old mines and several new discoveries. This important polymetallic province contains occurrences of gold, base metals, tin, tungsten, tantalum, platinum, palladium and aluminium. These resources have been exploited over the past century with periods of major interest during the turn of the century and during the past 20 years. Economically viable resources of predominantly gold, eg Pine Creek, Woolwonga, Brocks Creek and Union Reefs, and Ag-Pb-Zn, eg Woodcutters are currently in development or being mined. A variety of genetic models, ranging from magmatic through hydrothermal to syngenetic, have been postulated in the past for the formation of gold deposits in the Pine Creek Geosyncline. The first discussion on the regional geological factors that control ore deposition in the Brocks Creek-Howley District was by Sullivan and Iten (1952). They recognised that the most important ore deposits are associated with anticlinal and domal structures and that granites may be a controlling factor in the localisation of the mineralisation. More recently a group of authors, Needham and Roarty (1980), Goulevitch (1980), Nicholson and Eupene (1984), Sanger-Von Oepen, Friedrich and Kater, (1988), Nicholson and Eupene (1990) and Kruse, Whitehead and Mulder (1990) have suggested an exhalitive syngenetic origin, or remobilised syngenetic during dolerite intrusion and/or regional deformation, for gold mineralisation, especially those associated with South Alligator Group lithologies (eg Bridge Creek, Mt Bonnie group of mines and Cosmopolitan Howley). Studies carried out at the Bridge Creek and Western Arm Prospects over the last three years suggest that syngenetic models for gold mineralisation are less relevant to gold mineralisation in the Howley District than first thought (Wall, 1989; Partington, 1990). The Bridge Creek prospect has been cited as an example of a syngenetic-syngenetic remobilised deposit (Oepen, Friedrich and Kater, 1988) while the Western Arm prospect is more clearly a vein hosted epigenetic deposit and a comparison of the styles of mineralisation at both prospects will be made. The nature of the gold mineralisation at both prospects will be described and compared, and possible genetic models for gold mineralisation and their relevance to regional exploration discussed.

Jan 1, 1994

By B P. Wrench, N R. Steward, C Wu

A gold mine in southern China has transitioned from an open pit operation to a fully underground mine. An overhand mining method is used which requires the mined stopes to be filled with backfill having an unconfined compressive strength of at least 0.35MPa. Tailings from the process plant is deposited into separate flotation and Carbon in Leach (CIL) tailings storage facilities. The tailings has a high fines content and the thickener on site could only produce a dilute flotation tailings at a solids content of about 30 wt%. This resulted in two undesirable outcomes: the density of flotation tailings in the Tailings Storage Facility (TSF) was significantly lower than planned so that the TSF could not store the life of mine tailings and that the backfill product had to include a high percentage of manufactured aggregate and increased cement content to achieve the required strength. This paper presents results of a tailings study which identified that the flotation TSF would be capable of storing the remaining life of mine tailings if an amended backfill product made up of 100% of flotation tailings could be introduced. A 100% tailings backfill with the addition of 8% cement was developed by classifying the tailings and using the coarser fraction in the backfill. This backfill allowed 60% of the flotation tailings to be placed underground and only the remaining 40% in the flotation TSF. A new thickener was designed and installed to thicken the tailings and rheological testing of the tailings, using a closed loop pilot plant, provided parameters to upgrade the underground reticulation system to deliver cemented backfill to stopes throughout the mine and to deliver thickened tailings to the TSF. The revised design was implemented and has resulted in considerable cost savings. CITATION:Steward, N R, Wrench, B P and Wu, C, 2018. Optimisation of surface tailings storage and tailings backfill – a case study, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 454–464 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By R W. Wilson, A R. Branch, T S. Pooe

The original bulk air cooling system at this particular mine made use of two water chilling refrigeration machines to produce peak cooling of approximately 12 MWR with a downcast air temperature of about 7°C; however, as the shaft is not used for transporting personnel, the opportunity existed to supply more cooling to the mine by lowering the downcast air temperature. An ice storage facility has been constructed and provides a range of opportunities in operating the system: colder air temperature sent to the shaft, enabled by using near-zero degree water produced by melting ice to cool the air; electricity time-of-use management, by shifting electricity usage out of peak tariff periods; and increased peak cooling capacity, by melting ice while chilling water. Ice is created in the storage facility at night while the ambient air temperature is low and then melted to produce cold water when required by the cooling process. An ice dam was constructed and serpentine stainless steel coils installed where the ice is produced; one of the refrigeration machines was converted to chill a glycol solution to subzero temperatures to create the ice on the coils; a plate heat exchanger was installed to allow the glycol chiller to act as a water chiller as well; and a third spray stage was added to the bulk air cooler to utilise the near-zero water. This paper describes the thermodynamic design, construction and performance assessment of the new system, which is unique, novel and represents the state-of-the-art of this type of cooling system and energy management.CITATION:Branch, A R, Wilson, R W and Pooe, T S, 2015. Novel use of ice thermal storage for energy management on a mine refrigeration plant, in Proceedings The Australian Mine Ventilation Conference, pp 185–192 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By K Orth

The volcanic successions that host massive sulphide deposits are diverse in composition, facies types and facies relationships. They also show a variety of spatial and temporal relationships to mineralisation. In many examples, such as the Koongie Park Formation in Western Australia, the host succession includes more or less conformable syn-volcanic sills with peperitic contacts. Such sills can be an important source of heat for fluid circulation, influencing patterns of hydrothermal alteration and the location of co-eval and later mineralisation. The impact of syn-volcanic sills on the host succession depends in part on the initial porosity and permeability of the enclosing facies. The special properties of glassy pumice û being highly porous, permeable, and reactive û allow pumice-rich facies to preferentially focus hydrothermal fluid flow. However, the same properties promote early alteration and porosity reduction. Hence, the diagenetic and compaction history of pumiceous facies strongly influences their potential to host massive sulphide mineralisation. In contrast to pumice, dense glass has relatively low porosity, at least initially, and does not compact. Non-vesicular glass is a major component of submarine lavas, syn-volcanic intrusions and some volcaniclastic facies. However, especially in submarine settings, dense glass is commonly intensely perlitically fractured soon after eruption. The fractures greatly increase the porosity and permeability, locally accelerating diagenetic and hydrothermal alteration. In addition to false pyroclastic textures, altered perlite may exhibit false porphyritic textures. Silica- or feldspar-altered perlite kernels surrounded by intensely altered phyllosilicate domains can resemble phenocrysts in a fine grained groundmass.

Jan 1, 1999

By V Malysiak, N J. Shackleton

In the flotation of platinum group minerals pyroxene is a major gangue mineral. This study shows using zeta potential and ToF-SIMS analyses that when pyroxene is exposed to copper, nickel and/or calcium ions in solution at alkaline pHs a surface reaction occurs between the hydroxy species, in the case of copper and nickel, or divalent calcium ions and the pyroxene surface which influences the floatability of the pyroxene. Following exposure to copper and nickel ions at pH 9 addition of SIBX resulted in the pyroxene floating readily. It is also shown, in the case of copper, that the activating effect of the adsorbed copper hydroxy species can be reduced by the addition of complexing amines prior to SIBX. Proposals are made to explain these observations.

Jan 1, 2005

By S H. Li, H Z. Gu, A Huang

High aluminium steel is a promising advanced steel known for its exception properties and holds significant economic and strategic importance. However, the CaO-Al2O3-SiO2 based slag with high alumina content reacts vigorously with alumina refractories during the smelting process at high temperature, seriously affecting the safe and efficient production of furnaces and resulting in the formation of Al2O3-MgO non-metallic inclusions within the molten steel. This is a bottleneck problem for high-quality steel refining, and the key reaction path during the corrosion remains unclear. The dissolution reaction mechanism of alumina refractories in high alumina CaO-Al2O3-SiO2 slags under a weak static magnetic field was investigated in this work, using high temperature laser confocal microscopy and in situ radiation spectroscopy techniques. The results indicate that the interaction between the high alumina slags and the alumina refractories is governed by free radical reactions. The dissolution of alumina forms AlO and AlO2 radicals. The reaction rate increases with the C/S ratio of the slag due to its low polymerisation. The reaction between non-bridging oxygen and AlO2 free radicals accelerates the generation of AlO and O2ꞏ- radicals. The reaction layer composed of calcium aluminate is formed through the recombination of AlO, Caꞏ+ and O2ꞏ- radicals. The weak static magnetic field induces the Zeeman splitting of free radical pairs and intersystem crossing occurs, promoting the formation of triplet free radical pairs through the hyper-fine coupling effect. The reaction can be significantly inhibited as the triplet free radical pair does not meet Pauli’s incompatibility principle. This discovery perfects the structure theory of molten slags with radicals and provides supplement to the design of the highly slag-resistant refractories, and provides the theoretical basis for the development of external field protection technologies for high-quality steel refining.

Jun 19, 2024

By Stevenson C. H, Lynch A. J

The reasons for choosing autogenous grinding for the new Warrego concentrator of Peko Mines N.L. are discussed and the ores to be treated in the concentrator are described. The mill was designed on the basis of pilot tests carried out at Cobar and the performance of the mill has been most satisfactory both in its metallurgical and mechanical aspects. An empirical technique has been developed to predict mill performance for change in feed rate or feed size and a mathematical model of the mill is being developed for simulation and control work. The weight and size distribution of the mill load was determined at one set of operating conditions for use in the mill model.

Jan 1, 1974

Refractory gold concentrates and their roasted products have been examined by mineralogical and chemical methods, and the distribution of gold in the tailings after leaching has been Investigated.

Jan 1, 1989

A method for determining the relative degree of oxidation of concentrate samples was established, and various surface-active materials and protective systems were examined as oxidation inhibitors. Sodium oleate was-the most effective of the materials tested, and a plant trial

Jan 1, 1963

China has at least 200 collieries suffering from the problem of instantaneous outbursts of coal and gas. Strong outbursts often have occurred in geological tectonic zones and concentrated stress areas. There are some particular characteristics of these strong outbursts, including the effects of ground stress, gas pressure and the properties of coal associated with the outbursts.

Jan 1, 1986

By Stewart Gillies AD

Resource rent taxes are taxes which only become effective at such a time as a pre-determined rate of return has been achieved by an operation. Resource Rent Taxes have from time to time been considered for implementation in both Australia and New Zealand. The offshore petroleum industry in Australia is already subject to RRT as is the Roxby Downs (Olympic Dam) Mine in South Australia. Both the mining and petroleum taxation regimes in Papua New Guinea include a resource rent tax component called Additional Profits Tax.

Jan 1, 1995

By Newell R

The influence of layering on the rate of heat transfer through a packed bed consisting of particles of two different sizes and heat capacities has been determined by measuring the heat front velocity through beds of quartzite particles and iron ore pellets. The heat front velocity through the layered beds was less than that through a bed consisting of a random mixture of the par- ticles. This is due to the formation of an interface in which the smaller pellets in one layer penetrate into the layer of quartzite Below.

Jan 1, 1987

The production of copper by the Outokumpu direct blister process commenced in July 1988. The problems and incidents encountered in commissioning the main smelter equipment are outlined. Early difficulties were encountered in process control, hot metal handling, dust buildup in the off gas handling equipment, waste heat boiler tube failures, foam over of hot metal into the waste heat boiler and failure of ancilliary equipment.

Jan 1, 1989

Mining projects frequently fail to meet their financial objectives. A significant area of poor performance lies in the areas of resource estimation, reserve definitions, selective mining and metal accounting. The processes leading to the exploi

Jan 1, 1998

By Smith I. K

A Data Acquisition System with a capacity to monitor 2000 analog instruments has been installed at the mines operated by the Zinc Lorporation, Limited and New broken hill Consolidated Limited (ZC/LVbHC), New South Wales, Australia. Since commissioning in March, 1982, the system has proved its value in providing up-to-date information to both Rock Mechanics and Mining personnel. The paper describes the function of the major software and hardware components of the system, and identifies the advantages that an on-line monitoring system provides in the day-to-day operation of a large underground mine.

Jan 1, 1983

By T Galvin

Drilling and blasting at Westside Mine near Wallsend, NSW, has presented a challenge for Orica Explosives, Australia. The colliery produces 600 000 tonnes of steaming coal per year from two seams using surface mining techniques. Tapping into underlying coal will greatly improve the yield, but there are many issues which make this an enormous challenge. Hunter Valley Earthmoving engaged Orica Explosives to supply the explosives products and to provide much of the blasting expertise that is needed on the minesite. Hunter Valley Earthmoving and Orica Explosives have proven to be an outstanding, unified technical team on this project. The success of the team is based on good communication, progressive attitudes, extensive expertise in blast design and most importantly, care and accuracy in implementing the agreed upon designs.

Jan 1, 1999

By Reifenstein A

ACIRL's petrographers apply microscopic techniques to coal exploration, production, preparation and processing problems and research investigations as well as provide a commercial service for quality control of export coal shipments. This paper describes a number of case studies of applications of petrography to coal industry problems and coal research, including

Jan 1, 1989

Over a four year period from 1984 to 1987, a broad range of ground conditions were experienced in recovering old workings at the Walhalla mine in central-eastern Victoria. Access to the ore zone was gained via old workings and new development. The work included: Recovery of vertical and inclined shafts. Recovery of collapsed winzes. Recovery of level drives and crosscuts. Spiling through broken ground and old mullock. Pre-grouting of caved zones. New development using small-scale rail equipment and "bobcat" Loaders.

Jan 1, 1988

By Adranyl W. W

Sub-level caving with bottom ore drawing has gained wide acceptance in rich, soft, low magnetic iron ores because it provides moderate ore dilution and ore losses. The main problem here is the high rock pressure exerted on sub-level drives situated in the sub-level sill pillars. To reduce this effect, the ore block is divided into panels. This paper illustraes the method of determining the maximum panel width providing low maintenance cost of sub-level drives.

Jan 1, 1995