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By Tien J. C

Many factors (type of coal mined, water pump pressure, wetting agent concentration, etc) will affect the performance of a dust suppression system using a water spray in an underground coal mine. While a two-level factorial method is useful in

Jan 1, 1994

By Lu S, Zhou S

The flash smelting technology employed in Jinchuan demands a better mineral processing concentrate with an MgO content below 6.5 per cent. Two ways for MgO removal have been investigated in detail based on properties and process mineralogical characteristics of the rich ores in the number one mining area in Jinchuan. The key to the first way is the use of a new flowsheet which has two-stage grinding and separation followed by single-stage regrinding and multi-stage cleaning for the rougher concentrate. The second approach utilises two novel reagents, AT-131 and AT-202, which have been developed recently. Excellent metallurgical performance has been obtained in a commercial test and a batch test, respectively. The MgO content of flotation concentrate can be reduced to about six per cent.

Jan 1, 1996

By Durucan S

Uncertainty due to spatial and temporal variability of different pollutants found in soil, water and air is an important issue in the modelling of environmental impacts. Recognition of spatial environmental patterns is relatively straightforward to achieve by applying most of the well-known artificial neural networks or adopting a stochastic approach. However, it is the temporal component of the environmental variables that makes modelling of the environmental pollutants particularly complicated and challenging. This paper presents the results of a case study investigating the artificial neural network performance when modelling the spatio-temporal behaviour of environmental pollutants. The test case involved the modelling and prediction of the distribution of water quality indicators along a river from the point of discharge of treated mine effluents. The behaviour of river water quality indicators is rather complex and shows a lot of fluctuations due to a number of hydrochemical, hydrobiological and hydrodynamic factors. Results obtained in this study indicate that artificial neural networks provide a very powerful and robust method for simultaneous modelling of spatio-temporal behaviour of environmental pollutants.

Jan 1, 1995

In process industries, time-dependent random fluctuations of raw material characteristics and mass flow rates in bulk material or pulp flows cannot be always prevented for different reasons, eg because of the geological situation (no uniform formation of the deposit) or/and because of technological reasons (segregation in bunkers or on stockpiles). Since a long time, there has been practical experiences that such fluctuations can have negative consequences, eg: ò fluctuations of the final products characteristics, ò higher expenditure for process control, and ò worsening of technological characteristics (recovery, sharpness of separation etc). In the literature, there can be found a lot of details as to, eg the improvement of the sharpness of separation in a jig in dependence on the raw material blending (Kubitza, 1981; Gathen, 1983) or the decreasing flotation recovery with increasing raw material characteristics fluctuations in iron and potash ore processing plants (Bubnova, 1978). Up to now, however, these consequences of random fluctuations, eg on the separation efficiency were not predictable theoretically. It could be shown by means of the general model for mechanical macroprocesses (Graichen, 1989), that the reduction of input fluctuations passing a blending facility can be calculated in this way. In this example, the steady state of the process is the wanted one, but, in general, the model is able to describe also non-steady states of the process regarded. On the other hand, the general model of mechanical macroprocesses has been used successfully for modelling separation processes, eg cross-flow and air classification (Molerus, 1969; Neesse, 1991; Senden, 1979; Tichonov, 1973). That is why it was tried to model the influence of input fluctuations on the separation efficiency, that means, the impact of non-steady states - as a consequence of random fluctuations - on a separation process. The models discussed in the literature are related nearly exclusive to the steady state of the process. The reasons for that lie in the (relative) simplicity of the models and the fact that the steady state is aimed at by means of blending processes under practical conditions - because of the advantages mentioned above. These models cited have proved to be superior to other models, since the basic general model for mechanical macropocesses makes possible the consideration of turbulence acting in the process unit and influencing the separation process essentially. This is valid also for modelling the turbulent cross flow classification, applied to mechanical classifiers and hydrocyclones, where the correspondence between the separation characteristics (cut size, separation sharpness) calculated and determined experimentally is much better than for other models.

Jan 1, 1993

By Johnson N. W, Ralston J, Lauder D. W, Smart St C R

The flotation behaviour of the Hilton ore of Mount Isa Mines has been examined in the presence of two collectors (sodium ethyl xanthate (Ex) and sodium diisobutyldithiophosphinate (3418A)) over a range of flotation Eh values and collector additions. Tests were also conducted in the absence of collector to determine the relative contributions of natural and self-induced floatability of the major minerals in the feed. In these tests the influence of metabisulphite on the self-induced floatability of the minerals was also determined. Attention focussed on optimising the selectivity of galena flotation. It is shown that the Hilton ore sample contained lower levels of naturally hydrophobic iron sulphide minerals than are generally contained in the Mount Isa lead-zinc ore. Furthermore, the self-induced floatability of galena was less than that exhibited by the galena in the Mount Isa lead-zinc ore. Sodium metabisulphite (MBS) reduced the self-induced flotation of galena but had no effect on the natural floatability of the iron sulphide minerals.

Jan 1, 1991

By Johnston R. F

The factors which influence the reduction of chromite are investigated with special reference to Coobina chromite. This was compared with a South African chromite ore. The reduction characteristics are outlined and the reduction kinetics studied Temperature has the most significant effect, followed by particle size, silica addition and type of coal.Electron microprobe analysis of the products indicates that iron in the chromite is first reduced at temperatures above 1100°C, followed by chromium at around 1200°C. At temperatures greater than 1200°C metallic iron and chromium are formed simultaneously and subsequently give an iron-chromium-carbon alloy. It was observed that the metallic carbide contains a small amount of silicon. The decomposition of the chromite spinel was observed to pass through the FeO.Cr2O3, MgO.Cr2O3 and MgO.AI2O3 forms before slag formation. It is concluded that Coobina chromite is suitable for the production of ferrochrome if direct prereduction followed by intensive bath smelting is used.

Jan 1, 1994

By Gray J, Krouse HR, Changkakoti A, Morton RD

A group of stratabound-stratiform Fe-Ba-Zn-Pb-Ag deposits within the La Minita mining district of Michoacan, southwest Mexico have been investigated. The results of the study show that these deposits were generated around submarine hot-springs issuing in a Cretaceous island-arc environment. The exhalative mineralization, which is both epigenetic and syngenetic in character, was developed above fault-systems which constituted the loci of both volcanism and subsequent hydrothermal systems.Fluid inclusion data suggest two hydrothermal events during ore mineralization, one at 240¦C and the other at 161 to 205¦C, with salinities between 2.1 and 12.8 wt.% NaCl equivalent. Stable isotope data support a marine origin for the ore-fluids, as well as, for carbon and sulfur. Strontium isotope data suggest that Sr in the barites was extracted from the volcanics and limestones by circulating seawater. The ore-depositional environment was one of shallow, sub-tropical marine character, where mineralization was in part geochemically controlled by carbonate reefal facies within the volcanic/pyroclastic suite.

Jan 1, 1990

This paper deals briefly with three of the more controversial aspects of the geology of the Mount Isa ore deposits namely the geologic structures, the method of ore deposition and the origin of the ore.In the section on geologic structures, an outline is first given of the purely tectonic deformation advocated by the early authors. The current interpretation, which differs in the proposed order of events and causal forces, is then discussed. Other concepts, which attribute all or part of the deformation to sedimentary features or preconsolidation movement, are outlined ilnd commented on.The remaining two sections deal mainly with the better known lead-zinc orebodies. In the first of these a brief description and criticism is given of the early interpretation which was based on the deposition of successive waves of mineralisation which replacedindividual beds in the shales. The current ideas, which visualise emplacement of the ore between the beds rather than replacement of them, is then discussed. The final section develops the case for a sedimentary origin of the lead-zinc ores and broadly outlines the author's ideas concerning the evolution of the Mount Isa ore deposits.INTRODUCTIONAny consideration of the geology of Mount Isa must begin with the work of Blanchard and continue with that of Hall. Individually, or as co-authors, they published various papers on the geology of Mount Isa. Of these, the best known is their "Rock Deformation and Mineralisation at Mount Isa" (1941) which gave a comprehensive account of all aspects of Mount Isa geology.It is necessary to appreciate the limits set on geological knowledge of the mine and environs in 1941 by the extent of mine development and regional geologic studies. Underground, 7 level (897 ft.) was the lowest producing level. Development on 8 (1073 ft.) and 9 (1247 ft.) levels consisted only of exploratory drives and crosscuts in the vicinity of the Davidson Shaft. The tops of the 650 and 750...

Jan 1, 1961

The effect of accurate detonator delay timing on blast results can now be studied with the development of the ICI Electronic Detonator. This detonator has an accuracy and precision orders of magnitude greater than the current range of pyrotechnic delay detonators. A series of field trials have been conducted to quantify the effect of delay accuracy and timing on blast performance. These trials have demon- strated that delay timing can have a marked influence on blast fragmen- tation, muckpile displacement, blast vibration and airblast.

Jan 1, 1989

By Collings P. S, Adair D. L

The Upper Robe (Robe Gorge) deposits occur in Kumina Creek and the Robe River, some 20-40 km upstream from mining operations at Pannawonica. The Gorge Deposits were rec- ognised, mapped and sampled in 1962-3 and re- examined in detail in 1971. Approximately 180 mineralized occurrences were mapped in 1971 on 1:4800 scale and 50 of these were remapped in detail at 1:1200 scale. Eighty cross sections were measured and sampled and 300 geological maps prepared. In addition 88 holes totalling 7388 feet were drilled in three occurrences considered to have the greatest potential. The Gorge Deposits occur in the Robe Pisolite unit which forms thin remnant crusts, bay fillings and occasional cut-off meanders along the edge of the present streams. Less than 50 of the deposits have tonnage potential of one million or more. Consequently exploit- ation of the Gorge reserves must be considered as a very uncertain, long range possibility because the deposits are small and scattered throughout the gorges in the area, thereby necessitating costly railroad spur lines to gain mining access. Grade of the occurrences is extremely variable over short distances both vertically

Jan 1, 1973

The first stage in the refining of lead blast furnace bullion is the removal of copper and this is normally done as a batch process in open kettles,A number of attempts have been made in the past to establish fontinuous processes operating in reverberatory type furnaces, but the growth of accretions in the furnace has always presented a serious problem.This has been overcome in the plant of the Broken Hill Associated Smelters Pty Ltd at Port Pirie by the construction of a reverberatory furnace and ancillary cooling system of novel design.Although a number of mechanical and metallurgical problems still remain to be solved, it is claimed that a workable continuous copper drossing process has been established.

Jan 1, 1963

By D Fargher

BHP BillitonÆs Cannington operation began production in 1997 and is presently the largest tonnage and lowest cost single mine producer of both lead and silver in the world. The original design capacity was 1.5 Mtpa and this has progressively increased via a series of debottlenecking projects in both the mining and milling operations. In 2003, 2.39 Mt of ore was mined, whilst 2.31 Mt of ore was milled. In February 2003 Cannington received approval to expand the project to a sustainable capacity of 2.4 Mtpa. This resulted in underground development into the northern zone, upgrades to the concentrator, increased accommodation at site and power station capacity. The Cannington project development team implemented a partnership approach to the project. Fraser Osborn Engineering and Outokumpu Technology worked closely together with the Cannington team to meet all of the project constraints.

Jan 1, 2004

By Pell D

Mechanical cleaning of coal was porforined in a few small plants in New South Wales from 1577 brit the first large coal washeries were built by Broken Hill Wbprietary Company Limited and Australian Iron and Steel Pty. Limited in the late 1940's. Mechanization of colleries in the 1950bs was abcomp" anied by construction of many coal washing plants and in the 1960's the growth of the coal export trade gave further impetus to the coal preparation industry. Design of coal preparation plants in Australia is modelled on practice overseas. Planning of a new plant in- volves investigation of many factors both technical and economic and the preparation of a specification by the operator for the designer's guidance. A wide range of preparation processes and equipment is on offer, but the nature of the coal to be treated and the separating efficiency desired usually dictate process selection. Simple or moderately difficult separation can be achieved with jigs, shaking tables or water washing cyclones. Coal which is difficult to treat or which has to be cut at a specific gravity lower than 1.5 is normally washed in a heavy medium process. In large plants it is usual to separate the coal into large, small and fine fractions and concentrate each fraction in a circuit designed to suit the grain size handled.

Jan 1, 1969

The techniques originally developed to process digital images of Mars, later gained widespread acceptance when applied to Landsat data: they are now making a significant impact in fields of geology outside remote sensing. The three ingredients of success are seen to be firstly, the perceptual attributes of image displays and the use of colour; secondly, the absolute ability to register data from a variety of sources; and thirdly, the speed of specialist "interactive" digital image display systems. The future lies in further exploiting these attributes through a Geographic Information Systems (GIS) approach to data handling, integration and display.

Jan 1, 1986

By Wu H. W, Jones S. J

Australia wide, over 40 fly-in/fly-out mining operations and other forms of long distance commuting now exist, with coverage of about 5000 employees. The substantial majority of these operations are in Western Australia, with some mines also located in Queensland and the Northern Territory. In recent years new large-scale mining operations have adopted the fly-in/fly-out approach and it is important to note that no new mining towns have been constructed in Australia since the township of Roxby Downs was built in the late-1980s to service the Olympic Dam mine. An examination of fly-in/fly-out mining operations in Australia has been undertaken. A detailed survey undertaken in 1990 has been reviewed and another intensive survey undertaken to establish emerging trends. Results from both company and individual employees point of view have been analysed. A section examines the views of professional employees and the influence of fly-in/fly-out on career development. Bus-in/bus-out coal mining operations are emerging in Queensland's Bowen Basin. These operations commute their employees into the mine site for compressed working schedules while the mine employees' families are domiciled in regional cities such as Mackay. A review of the issues associated with the development of long distance commute coal mining operations in Queensland's Bowen Basin is performed and two case studies examined.

Jan 1, 1997

Nippon Telegraph and Telephone Corporation (NTT) developed a new construction method (the M-2 method) that could drive a long, curved small-diameter tunnel (4>1.2 m) without human labor. This method employs the cast-in-place lining system, using quick-hardening resin mortar, so that it can greatly increase the driving distance and execute both long distance driving (longer than 500 m) and curved driving with a radius of curvature of 200 m. Furthermore, the central control system with a mini-computer in a vertical shaft enables all work in a small-diameter tunnel, i.e., excavation, lining, and transportation of excavated soil and materials, without human labor. NTT conducted several field tests and a Practical Application Test (P.A.T.) under a public road bearing great traffic. Good results were obtained and the practicability of this method was demonstrated. Therefore, from now on, NTT will apply this ii-2 method to drive telecommunication cable tunnels in urban areas. This method will also be applicable to constructing public tunnel facilities, such as for water, sewage, electricity and gas.

Jan 1, 1987

By Lye GN

Rock mechanics investigations have shown that some major slopes in the Panguna pit would be stable at angles in excess of 500 providing near-surface instability could be controlled. Excavation of final batters at angles between 55¦ and 60¦ is now being carried out using D10 dozers with berms at 45 to 60 m centres. A trial slope with berms at 90 m centres is planned. Shotcreting of weak zones combined with crest reinforcement, with rock anchors and dowels, is used to provide protection against erosion and toppling of the crests. Overall slopes excavated in this way are of the order of 10¦ steeper than slopes obtained by blast and shovel excavation.

Jan 1, 1986

By R Trueman

An improved ability to predict dilution for narrow vein deposits enables more accurate economic comparisons between mechanised longhole stoping and other narrow vein mining methods, as well as reducing uncertainty surrounding dilution estimates for deposits at the prefeasibility/ feasibility stage. This paper proposes narrow vein dilution prediction and minimisation strategies for both greenfield sites and operating mines, respectively. The narrow vein dilution method (NVD method) is a tool for more accurately predicting longhole narrow vein dilution. The method is based on a new concept called benchmark stoping width. Benchmark stoping width is based on probabilistic analysis of overbreak distributions from a typical longhole narrow vein mine. The premise for the NVD method is that dilution associated with longhole stoping can be predicted using the benchmark stoping width. In addition to dilution prediction, the NVD method also includes strategies for narrow vein dilution minimisation generally, including; filling, cablebolting, stress relaxation, extraction sequencing and blast overbreak.

Jan 1, 2008

By Brady KT, Pattenden G

A laboratory size solvent extraction apparatus has been constructed, which incorp- orates three stages of countercurrent extraction, followed by two stages of counter- current stripping. The model uses a gravity flow system from one stage to another and air lift pumps to recirculate organic and aqueous phases. A novel pump/mixer system is used to transfer solutions from the mixer compartments to the settler compartments. The model has proven valuable in the teaching of solvent extraction principles.

Jan 1, 1984

The Drummond Basin is a large intracratonic basin which developed in central Queensland during Late Devonian to Early Carboniferous times. It is postulated that the Drummond Basin developed as a foreland basin, to the west of a probable west dipping continental margin volcanic arc and subduction zone. The Drummond Basin sequence has been s,ibdivided into three tectono-sedirnentary cycles. Cycle I forms the base of the sequence and comprises thick sequences of intermediate to felsic volcanics and proximal volcanolithic sediments. The volcanics, particularly in the northeast of the basin, occur in separate sub-basins around what were probably isolated eruptive centres. In contrast, the rocks of Cycle 2 and Cycle 3 have been deposited during episodes of broad, basin wide subsidence. Five major igneous episodes, some of which may be co-magmatic, are recorded in the eastern Drummond Basin and environs between the Late Devonian and the Early Permian. The first and second episodes occurred during the Late Devonian to Early Carboniferous and are represented by the volcanics in Cycle 1 and Cycle 3. The third episode involves the intrusion of granitoids of Early Carboniferous age into the Drummond Basin sequence. These occur in the Ukalunda area and are related to gold mineralisation at Ukalunda and Valhalla. Episode four includes the felsic volcanics of the Bulgonunna Volcanics. This episode does not appear to he broadly auriferous but gold mineralisation does occur in possible basal Bulgonunna Volcanics at Mount Coolon. The final episode includes a suite of granitic intrusives which intrude the Bulgonunna Volcanics and which are considered to be co-magmatic with them. These intrusives do not appear to be generally associated with gold mineralisation. Gold mineralisation is widespread in the north- eastern Drummond Basin and environs. It is probable that the gold mineralisation is concentrated in epithermal cells during the Late Devonian to Early Carboniferous volcanic cycles. This style of mineralisation appears to be related to tectonic setting in modern analogues.

Jan 1, 1989