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The implementation, during recent years, of the concept of distributing chilled water to improve cooling at the working faces represents a very important innovation for the mining world. In a logical extension to that concept it has been recognized that distribution of the cooling water at high pressure would provide a potential source of energy for driving water powered hydraulic machinery such as rockdrills, water jets for moving rock, and support props, in the workings. With this in mind, the Research Organization of the Chamber of Mines of South Africa is pursuing the development of such a dual system that will provide cooling in a deep mine and, at the same time, drive hydraulic machinery. A comprehensive design of such a system has been completed and has shown the concept to be entirely feasible technically using technologies currently available. A pilot system is working in a mine shaft 2000 m deep giving a pressure of 20 MPa at the bottom of the shaft and distributing the cold water into the workings at a pressure of 17 MPa. The system shows considerable potential for improving existing mining methods and will open the way for the development of new mining methods for deep mining operations.

Jan 1, 1986

By Biswas AK, Hayes P

During the reduction of iron oxide pellets in the blast furnace it has been found that catastrophic swelling (up to 300% volume increase) can occur. Although the burden preparation conditions can be designed to avoid this phenomenon the exact reason and mechanism of the swelling has yet to be clearly identified. Swelling of the burden is undesirable since it reduces the interparticulate voidage in the blast furnace thus reducing gas flow through the stack resulting in low production rates of iron. The present study differs significantly from previous experiments in that reduction is carried out on single crystals of wustite thus the problems of control of gas composition and specimen preparation are minimised. The microstructures formed on reduction have been examined by optical and scanning microscopy. Pure wustite and wustite doped with various levels of CaO have been examined after reduction in controlled CO-CO 2 gas mixtures at 968¦C. The catastrophic swelling on reduction coincides with the formation of an unusually open iron structure in which the iron appears as whiskers or needles as previously reported. The spacing and thickness of the needles are shown to vary with impurity content and gas composition. Metallographic examination has shown in addition, however, that the whiskers do not necessarily constitute the only product form of the iron produced and in CaO containing wustites with less than - 2% CaO there is a transition from needle growth to porous growth of iron. Thus the % swelling of the oxide particles is dependent on the initial size of the oxide grains. Samples of FeO - 10% CaO exhibited a previously unreported product inorphology associated with the nucleation of 2CaO.Fe203.

Jan 1, 1980

In Australia, current production of rare earth element (REE) minerals, monazite and xenotime, occurs as by-product from titanium-enriched placers and beach sands. Undeveloped REE resources are associated with carbonatites, alkaline igneous rocks, pegmatites, phosphorites, cemented fluvial sandstones, and uranium mineralisations. The REE are held within a range of minerals including silicates, phosphates, a1uminophosphates, carbonates, and oxides. The development of these REE resources may require new processing and extraction methods. The distribution of REE in the currently mined ore minerals, monazite and bastnaesite, does not match that requested by the market. Exploration for new REE resources should be focused on ores with more marketable REE distributions, particularly with heavy REE, neodymium, samarium, europium and yttrium enrichments. Such ores occur within alkaline igneous rocks, in laterites overlying carbonatites and alkaline igneous rocks, and in placers derived from low-grade regional and contact metamorphic sediments. Lateritic REE deposits may be easily and economically mined by shovel in open pits and are unlikely to require extensive crushing and milling. In addition, lateritic REE clay deposits may be processed by simple hydrometallurgicaltreatment mehtods.

Jan 1, 1991

The Australian Mineral Industries Research Association, set up by the mineral industry in 1959, acts as a research and development broker and manager for the industry. In 1984/85 it contracted out just over $3 million of projects. Its structure and method of operation is described and highlights of some of the successful projects are given. The complex process of developing new proposals is described. This involves the establishment of effective communication networks within the industry and between the industry and research personnel working outside it. The advantages of the industry tackling some of its problems on a jointly sponsored basis are listed. Possible avenues for future development by the Association are given.

Jan 1, 1986

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 series of events leading to the adoption of more complex flotation circuits for coal have been reviewed. In essence, it has been concluded that ac- ceptable overall flotation recovery will only be obtained when efficient distri- bution of collector over all the component feed size fractions is ensured. The achievement of this goal is most likely to be obtained by feed classification and separate flotation of appropriate size fractions. The adoption of such a phil- osophy, however, imposes a number of process problems of both a chemical and an engineering nature. Some of these problems have been identified and possible solutions discussed. A case is emerging for the development of a new generation of flotation cells designed specifically for the flotation of classified coal and for the development of a series of novel re- agents which have the propensity to float middling particles.

Jan 1, 1984

By Hoffmann CF, White NC, Tedder IJ, Wood DG

Since the discovery of Pajingo in 1984, the northern Drummond Basin has emerged as a significant new gold province, and has become the focus of intense exploration for epithermal gold mineralisation. Prospects in the Conway area are hosted by felsic to intermediate lavas and volcaniclastic rocks near the base of the Drummond Basin sequence. These Drummond Basin rocks appear to represent favourable hosts to mineralisation because they are cut by structures which could have focussed and channelled fluids on a regional scale, and because they constitute a possible source of gold and, perhaps more significantly, sulphur for the transport of gold. Prospects in the Conway area are up to 15 km2 in area, and are of the adularia-sericite type. They illustrate many of the classic features (siliceous sinters, alteration mineralogy, and fluid characteristics) recognised in epithermal deposits. K-Ar dating of sericite alteration in three of the prospects has produced a range of ages from 283 to 334 Ma, suggesting that the systems are the product of multiple hydrothermal events.

Jan 1, 1990

By Luke K. A

Pressure on production at New Zealand China Clays has led to the development of a dewatering control loop for fine halloysite china clay. The development was based on the analysis of data from the automation of plate and frame filter presses. The analysis of the data has led to process changes, and the ability to quickly solve dewatering problems. As a result of control in the dewatering circuit press times have reduced on average 117% and output has increased proportionally.

Jan 1, 1989

By Kallioinen J

This paper discusses different possibilities to enhance coarse particle flotation using forth manipulation and improved flotation cell design. Experiments were carried out in laboratory, pilot and industrial scale ranging from 0.0015 to 100 m3/axle. During the work it could be shown that the conventional idea of one single flotation cell type for both fine, immediate and coarse flotation of coarse and fine particles need different impeller tip speeds and a different froth control objective for effective operation. For optimal operation for coarse feeds the tip speed must be reduced and the froth vertical velocity must be increased to compensate the respective drainage velocity and also the water film thickness must be taken care of. Turbulent eddies below the froth interface should be suppressed. The paper discusses the effects of different froth manipulation variables like froth vertical velocity and froth residence time to the recovery and selectivity. A function has been developed, between the residence time of the froth and the flotation cell's ability to produce an improved concentrate grade as a function of different operating and froth manipulation variables.

Jan 1, 1993

By J Cook, S Pike, D Pridmore

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The application of high-resolution seismic reflection to map structure and/or mineralisation in hard rock environments has progressed significantly in the last decade. Improvements in equipment, field practice, processing and understanding has seen the seismic reflection technique emerge as a cost-effective tool for high-resolution three-dimensional structural and lithology mapping to depths far greater and with superior accuracy than other more conventional geophysical techniques.This paper outlines results and preliminary interpretation of 2D and 3D seismic reflection surveys aimed at defining fault zones and locations for quartz load development in favourable host lithologies at the Cracow low-sulfidation epithermal gold system in Queensland, Australia.As this is possibly the first time that high-resolution seismic reflection data has been used to define the structurally-controlled location of low-sulfidation epithermal gold mineralisation, an important aspect of this work was the derisking or due diligence steps taken prior to commissioning the full 3D surveys at each site. This included full wave sonic logging, vertical seismic profiling and trial 2D lines. Interpretation of the 2D profiles and the drilling of interpreted structure provided the confidence to proceed with the full 3D survey.The advantage of collecting 3D data extends beyond ensuring that the received reflections are located correctly in 3D space. The final 3D data cube can potentially map the entire fault network, thus highlighting flexures and changes in orientation of the structures both vertically and along strike, which is an important aspect in the deposition of gold and for direct targeting.CITATION:Smith, R, Cook, J, Pike, S and Pridmore, D, 2015. Application of high-resolution seismic reflection surveys to exploration for blind vein systems at the Cracow low-sulfidation epithermal field, in Proceedings PACRIM 2015 Congress, pp 77–84 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

The Comstock Lode, a world-class precious metal vein district near Virginia City in western Nevada, U.S.A. (Fig. 1), produced 8.3 million ounces (0.28 X 106 kg) of gold and 193 million ounces (6.56 X 106 kg) of silver during the period 1859 to present (Bonham and Papke, 1969). More than 95% of production was from the Comstock fault, while the adjacent Silver City, Occidental and Flowery vein systems produced about $10 million (U.S.). Within the Comstock fault high-grade ore bodies, or bonanzas, were distributed over 2.3 miles (3.8 km) along strike and persisted to >3000 feet (>900 m) below the surface (Fig. 2). Bonanzas consisted of as much as 1.4 million tons (1.3 million tonnes) of ore grading up to 1.9 oz./ton (65 gm/ton) Au and 30 oz./ton (1020 gm/ton) Ag (Table 1). Some bonanzas occurred in the main Comstock fault plane while others, including the highest grade bonanzas, formed in hangingwall frac- tures. After 1880 most ore consisted of lower-grade vein material surrounding mined- out bonanzas and large volumes of mineralized vein and wall rock in the Comstock hanging- wall that were mined from open cuts. Deep mining was hindered by large quantities of hot water and bad ground which ultimately defined the limits of underground production. The widths and richness of Comstock bonanzas strongly influenced U.S. mining law, milling and underground mining methods, and securi- ties regulations that are in practice today. Within the district Mesozoic metasedimentary rocks, metavolcanic rocks, and granitic in- trusions are overlain by Miocene volcanic rocks (Thompson and White, 1964). Veins cut all lithologies. Miocene volcanic rocks and their K-Ar ages (Vikre, McKee and Silberman, 1987) include Santiago Canyon rhyolite (22

Jan 1, 1987

By J Manuel, R Muddle

The demand for iron ore has increased significantly in recent years, with new iron ore sources being mined to meet this demand. As the composition of sinter blends changes with the availability and cost of iron ore, so too does interest in the impact of new ore types on granulation and ultimately productivity. This paper describes a study into granulating characteristics of seven iron ore types, including various hematite and goethite ores. The effect of ore type on feed moisture requirements, green bed permeability, green bed strength and granule size distribution was examined for single ore blends containing coke, flux and returns. The ore size distribution was varied in these blends and its effect on granulating characteristics examined. It was found that the optimum moisture requirement of the ore was more dependent on ore type than ore size distribution, but ore size distribution (and specifically intermediate particle loading) had a greater effect on green bed permeability. The saturation moisture value for an ore was found useful in predicting both optimum granulation moisture and green bed permeability.

Jan 1, 2005

The physical phenomena which influence gas flow in the bosh and hearth of a blast furnace are discussed including the hold-up of slag as a mechanism which can result in a flooding condition. An equation is defined which describes the limitation to wind volume arising from the flooding condition. Implications of the various factors influencing bosh and hearth gas flow on furnace operation are discussed. Coke quality is shown to be the most important factor in the aerodynamics of these zones and coke requirements are defined for the Port Kembla No. 5 BF which has an inner volume of 2670 m3.

Jan 1, 1975

By Shrivastava P

The iron orebodies of the Pilbara region are formed by supergene enrichment of banded iron formation and rarely do such processes produce orebodies with uniform grade distrib- utions. The orebodies being mined or developed have to be worked to grade/quality constraints imposed by contractual agreement rather than natural characteristics. Hence it is imperative to use a non-biased ore reserve calculation method. The geostatistical study of a typical iron orebody is presented. Emphasised are the geological characteristics of the orebody manifested as a variable grade distribution of iron and impurities; the determination of variogram model; subsequent uses of the model for computation of ore reserves and kriged lock estimates; computation of dispersion variance and conditional simulation of orebody.

Jan 1, 1977

High resolution seismic profiling has proved a cost effective tool for defining the structure and seam geometry of Late Cretaceous-Late Miocene age lignite deposits in the South Island of New Zealand since 1981.In 1985 a total of 45 km of Mini Sosie seismic reflection was carried out in the Benhar, Hawkdun and Ashers-Waituna deposits as part of a major multidisciplinary resource investigation funded by the Liquid Fuels Trust Board. For each deposit the seismic programme involved integrating four or more intersecting Mini Sosie traverses with a grid of 1000 m spaced geophysically logged drillholes. The objective was to detect faults, with displacements ranging 30 - 100 m, which might impede mining using bucket wheel excavator systems at depths down to 300 m below surface.In general the quality of processed seismic data was high and with the assistance of ynthetic seismograms and other geological information, it was possible to identify a number of significant previously unknown faults. The success of this seismic programme ha shown that high resolution seismic profiling, used in conjunction with relatively low density drilling, can produce valuable structural and tratigraphic information at an early stage of open pit mining investigation.

Jan 1, 1989

By Koppe J. C, Dimitrakopoulos R, Costa J. F

Grade control and the delineation of ore/waste in open pit operations is traditionally based on the comparison of estimated grades with an economic cut-off. This paper deals with an alternative approach to grade control based on estimating gra

Jan 1, 1998

By Olofsson O, Durance M-V, Villeneuve J

Modelling of the Sala Agitated Mill (SAM) using a simplified solution to the population balance approach has been carried out. The rate of breakage is modified by the mill power, providing predictions of the resulting product size distribution for different grinding conditions and mill sizes. The power of the mill is estimated by a physically derived function, using an assumption that the mill power consumption mainly arises from the ball to ball friction within the mill. The grinding efficiency, depending on the media ball size and pulp density is approximated in the model. Experimental work on grinding a complex sulphide ore using a pilot scale SAM 7.5 has been carried out. Good agreement has been found between the data from the test campaign and the simulated values. The model has also been validated with experimental data from a pilot grinding of calcium carbonate and from an industrial mill. The model is included in the USIM PAC simulation software.

Jan 1, 1995

By Filigenzi M. T

Stresses around mine openings at depth can cause the surrounding rock to fail, releasing stored strain energy. When this happens, the rock may literally explode or `burst' into the opening without warning. As mining progresses deeper into the earth, the possibility of seismic events and rock bursts increases. Researchers at the US Bureau of Mines (USBM) are currently studying seismic activity in three underground hard-rock mines in the United States: the Homestake Mine, Lead, SD; the Lucky Friday Mine, Mullan, ID; and the Sunshine Mine, Kellogg, ID. Waveforms from seismic events are recorded by personal-computer-based hardware and software. This information is archived and transferred from the mine sites to the USBM via modem communication links. Then, using USBM-developed software, the events are analysed to determine various parameters, including magnitude, frequency, and location. In addition, researchers are modelling the deep levels of the Homestake Mine using a finite-element code. These models generate stress and displacement values for a given loading condition. By studying material properties, in situ stresses, and seismic activity along with actual scope sequencing, researchers can make correlations between stresses induced by mining and the frequency and magnitude of seismic events. Information on seismic events coupled with results from finite-element analyses have increased understanding of rock mass behavior and the mechanisms that may lead to rock bursts. Optimisation of slope sequencing designs as a result of these studies could reduce rock burst hazards.

Jan 1, 1995

The paper is aimed at mining engineers and other mining practitioners in the metalliferous mining industry who are considering the use of roadheaders and wish to understand the basic geomechanical and operational principles controlling their performance. The paper aims to address metalliferous minersÆ general unfamiliarity with roadheader technology, which is one of the factors which has limited the application of these machines in such mines. The historical development of drag tool mechanical excavation machines is briefly discussed, and factors affecting the application of roadheaders are mentioned. The mechanics of cutting with drag tools is then reviewed as are the effects of these and tool wear on tool performance. The implications of tool performance to roadheader performance are mentioned, the potential benefits of high pressure waterjet assistance are discussed and the relative performances of different tool types and materials are compared. Roadheader performance factors including productivity and utilisation are mentioned, and the state-of-the-art of conventional roadheaders is discussed in the context of machine weight, power and cutting head configuration. The influence of these and rock strength on machine productivity is analysed. Alternative, developing technologies are discussed which may extend the effective use of mechanical excavation into stronger rock masses which are beyond the range of conventional roadheaders. Finally, conclusions on these discussions are presented, along with recommendations for continuing research and development.

Jan 1, 1997

The Sydney Coalfield, Nova Scotia contains extensive undersea longwall mining operations which are expected to continue well into the 21st Century. A long term research program has been initiated by the Cape Breton Coal Research Laboratory to investigate the full spectrum of problems associated with undersea mining and develop specific guidelines for use by the mine operator. At present, research is centred on the detailed evaluation of existing undersea sub- sidence guidelines, the identification and development of instrumentation capable of moni- toring seafloor subsidence profiles and the effective sealing of offshore exploration boreholes. In addition, work is also planned to examine in situ strata permeability changes occurring between the mining horizon and seabed and the feasibility of using artificial islands.

Jan 1, 1986