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By Dawson RD

For the past 45 years, the casting of refined lead ingots by The Broken Hill Asso- ciated Smelters Pty. Ltd. (B.H.A,S,) at Port Pirie has been mainly by use of manually operated rotary casting wheels of Newnam design. This style of operation was quite satisfactory as far as standard of product was concerned, but was manually intensive and a relatively high cost operation. With most other large scale lead producers already using automated-casting equipment, an investigation which commenced in 1966, progressed through stages of enquiry, design and development until the present plant commenced trial operations in late 1973, and fully operative in late 1974. While certain features of the plant are sed on overseas practices the plant was signed and built within Australia to BRAS ecifications. As constructed it consists two almost identical casting lines each pable of producing 25 kg ingots at 25 tonnes r hour using straight line casting machines d automated stacking weighing and strapping

Jan 1, 1975

This paper examines the interplay between longwall support design/geometry features, operational controls and geological features on ground response. Experience from several investigations is used to demonstrate the influence of factors such as longwall support capacity and geometry, setting pressure, coal seam strength and stiffness, tip-to-face distance and hydraulic supply and control system parameters on longwall ground response. These factors are then used to outline the requirements on key controls such as retreat rate and cutting height and their influence on allowable roof convergence. The ground response curve concept as a means to provide graphical representation of longwall support and strata interaction processes is presented. The approach was developed to address the requirement for a practical longwall support evaluation and selection tool that can take account of support load influences such as changes in roof geology or cover depth. An example of the comparison between single pass longwall and top coal caving in a thick seam environment is given to demonstrate the influence of the various factors discussed.

Jan 1, 2005

The originally estimated mine life at Kidston (starting 1984) was 12 years. Through a continuing process of re-evaluation and improvement in the operation and by expanding the geological knowledge in the region, the mine life has been considerably extended. With falling grades and harder ore, the additional reserves have come with increasing risk - not only in an economic sense associated with diminishing profit margins but also operationally, requiring innovative milling technology and geotechnical designs to provide a lower cost environment for continued profitable mine production.

Jan 1, 1994

Before proceeding to the main portion of the above subject, a few remarks as to the general question of our mill slimes seem called for, and, with this in view, it is intended to briefly refer to the salient, points connected with their production, treatment and disposal at the mills.It is well known that, owing to the inticate mixture of the constituents of our sulphide ore, 'a very great deal of crushing and grinding is required to detach the particles of galena from the zinc blende and gangue of the ore, and it will be readily understood that, in this operation, a considerable amount of the material is converted into a slime which consists of minute, but ,(as can be see~ under a glass) well definied particles of all the constituents· 6f the ore arid combinations thereof, the relative proportions of which depend on the dual characteristics of hardness and abundance of the different constituents. An analysis of the slime shows the contents to be as follows :-Galena (PbS)Blende (Zn S)Pyrites (Fe Sll)Ferric Oxide (Fell Os)Ferrous Oxide (Fe 0) contained in garnetsOxide of Manganese (Mn 0) contained in rhodonite and garnets

Jan 1, 1903

The Greens are asking the question: what do our mining towns look like in 2050 and how can we be better prepared? The resources boom brought enormous profits to the main players and was partly responsible for insulating Australia through the worst of last year's global economic turmoil. However, with indicators of a resurgent mining boom, it is essential we learn from the recent past. The last boom saw housing stress at levels unseen in the big cities, health services strained to breaking point, and Aboriginal poverty side by side with some of the most lucrative industrial precincts in the country. Much of the wealth still flies right over the heads of regional communities as fly-in, fly-out operations proliferate.   Behind these local stresses, resources booms rely on the stripping of non-renewable resources which will eventually run out, and the unique environment of the north-west is taking a battering.    Communities of the north-west have a perilously narrow economic base which must be broadened if townships of the Pilbara and Goldfields are to avoid the fate of places such as Goldsworthy and Wittenoom. Unless this is informed by local communities, decisions will be made in capital cities thousands of kilometres away by people largely ignorant of the unique conditions prevailing in regional Western Australia.   Global climate change negotiations and oil depletion will heavily penalise emissions-intensive economies like Australia which fail to keep up as the world moves to a low-carbon environment. This is an ABSTRACT ONLY no paper was prepared for this presentation.

Jun 1, 2010

By E Wan, K Stokes

Since 1978, the nickel concentrator at Leinster has been subject to continuous change. In 1971 a significant nickel sulphide deposit was discovered on Leinster Downs Station, within three years the extent of the deposit was determined. In 1978 the Agnew Mining Company began production of nickel concentrate from the Perseverance Mine and continued to do so until production ceased in 1986. In 1988 WMC purchased the mothballed project and began the first phase of many expansion initiatives. Milestones in the life of Leinster have included:open cut mining of the Perseverance orebody and the discovery of the RockyÆs Reward orebody, as well as the metallurgical challenges in treating each of these; underground mining at both Perseverance and RockyÆs Reward; construction and commissioning of the WMC grinding and flotation circuits; variations in the reagent schemes, including the introduction of æliquidÆ reagents; development of mill linings to reduce maintenance; circuit re-configuration and simplification; development of Harmony open cut; strategies for increasing throughput at the drier; and changes to tailings facilities to cope with increased throughput. This paper outlines the steps which have been required to expand the Leinster Nickel Concentrator from 650 000 tpa to 2.5 Mtpa and those steps which will be required in the future.

Jan 1, 2000

By Cox I

Raiseboring is a technique that has become popular in modem mining engineering since the early 1960s. A study has been undertaken at the University of Queensland to determine important factors affecting the optimum diameter of raisebored shafts, excluding local parameters such as the maximwn excavation size that a particular rock type can safely accommodate.This model is used to examine each of these factors and the results indicate that the optimum diameter for raisebored shafts is generally between four and six metres.

Jan 1, 1991

By Richmond GD

The Hellyer concentrator of Aberfoyle Limited commenced production in 1989 processing a fine grained, massive sulphide ore containing Zn, Pb, Ag, Cu and Au as values. Four concentrates are produced - copper/silver, lead, zinc and bulk (Pb/Zn) - with overall payable recoveries (1991) of 80 per cent Zn, 55 per cent Pb, 50 per cent Ag, 30 per cent Cu and ten per cent Au. Metallurgical development work commenced immediately after plant commissioning, and continues. The flotation response and liberation analysis on a size basis highlighted reagent balance problems associated with tower mill regrinding of sphalerite, poor conditioning of flotation pulps, poor selectivity for fine galena, and insufficient liberation. These were the main causes of values lost to tailings, values reporting to the 'wrong' concentrates and of impurities in the concentrates. Modifications to tower mill regrind circuit operation, and the use of improved conditioning techniques have greatly improved concentrator performance, particularly in the finer (-5 micron) size fractions. Studies of concentrator and laboratory flotation by size and liberation analysis are the basis of diagnostic metallurgy. The techniques used to evaluate the improved concentrator performance are discussed.

Jan 1, 1993

Under South Africanncoalmining conditions, in the majority of instances coal is won using the bord and pillar system without pillar extraction. Examples demonstrate that strata control policy has an effect on practically all aspects of mining: (1) the choice of mining method; ((2) degree of coal recovery; (3) effect on productivity; (L}.) integration of'-support techniques with other operations. This is confirmed by use of modern research results and computer simulation. Although the examples are drawn from South African experience, the conclusion is generally valid. Strata control problems cannot be solved in isolation but as an. integral part of overall mining policy.

Jan 1, 1971

The history of black coal as a fuel dates back in Europe more than 2,300 years, and possibly longer in China. Originally the mining of coal was done by underprivileged people, but with the industrial revolution and the dawn of mechanisation, the status of the coal miner improved. The improvement continued to the present day. Coal miners now take an important role in industrialised countries and enjoy a high standard of living. The miner is amongst the highest paid and best technologically served in any industrial activity. The abundance of coal relative to alternative fuels and its widespread occurrence, brings with it a prosperity much valued in those countries with significant resources such as Australia. Coal will play a major role in easing the world energy shortage. In addition to the conventional usage, throughout the world coal gasification plants are in various stages of development. Coal liquefaction plants are beyond the drawing board stage. Slurry pipelines to supply coal for direct burning in electric generating and other plants are planned. In the current atmosphere of environment consciousness, Australia has to contend with people with only marginal interest trying to influence coal mining activities to the detriment of the overall prosperity of Australia. Fortunately enlightened legislation is the greatest protector of the environment and in many instances great improvement to the environment ensues after mining has passed. With its vast resources of black coal Australia can look forward to a significant role in future supply of fuel. As a result of the trade and industry involved, Australia can become an even more influential country in world politics, trade, and the setting of high living standards.

Jan 1, 1975

By Rivers CJ

The Brolga deposit is a Ni-Co enriched laterite, formed over intensly serpentinised peridotites of the Marlborough Block. Basement lithologies at Brolga consist predominantly of serpentinised dunite, with lesser massive serpentinite shear, gabbro and harzburgite. Investigation of the deposit has defined 17 different varieties of saprolite, ferralite (limonite), and ferricrete. Different combinations of these varieties form three distinct lateritic associations, the Hard, Soft and Dyke Associations. Recognition of key textural and mineralogical features in each association, an understanding of basement geology, and an awareness of current climatic conditions, suggest that: 1. both the Hard and Soft Associations have formed under relatively dry climatic conditions; 2. the Soft Association reflects much poorer groundwater drainage than the Hard Association; and 3. the Dyke Association has formed from a gabbroic basement, and has also been affected by restricted groundwater drainage, caused by poorly permeable marginal serpentinite shears.

Jan 1, 1996

By Graham J

The successful processing of arsenopyritic ores is difficult and will be facilitated by a better understanding of the mineralogy of gold within arsenopyrite and the type of arsenopyrite in which gold is taken up. Solid solution gold in arsenopyrite is now well documented, and is a significant cause of refractory behaviour in gold processing. Investigations of the crystal structure and stoichiometry of arsenopyrite by X-ray diffraction, electron microprobe analysis and convergent beam electron microscopy have been carried out in order to understand how the gold is incorporated into the structure. Variations in stoichiometry, particularly the As:S ratio, of arsenopyrite leads to variations in structural parameters. These variations result in slight changes in thermal behaviour. The distribution of invisible gold in an arsenopyrite grain is generally non-uniform and synthesised samples contain up to 2 wt per cent gold. A transmission electron microscopy (TEM) technique called ALCHEMI is being used to identify the substitution site. The process of gold agglomeration together with evidence of an ordered breakdown of arsenopyrite to pyrrhotite has been documented with the use of TEM. An arsenopyrite grain containing invisible gold was heated with an electron beam resulting in recrystallisation of arsenopyrite to pyrrhotite with arsenic being expelled. The gold is mostly insoluble in the pyrrhotite lattice and therefore exsolves out and combines with other gold atoms to form droplets at the boundary of the pyrrhotite.

Jan 1, 1992

By W J. Bruckard

In Australia, ilmenite is produced from beach sand deposits. These deposits contain varying quantities of the valuable minerals zircon, rutile and ilmenite, along with a variety of other minerals. The valuable minerals are upgraded using combinations of gravity, magnetic and electrostatic processing techniques to yield high-grade products. One of the penalty elements present in ilmenite concentrates is chromium, present mostly as chrome spinels. This mineral is particularly difficult to separate from ilmenite, as the properties of the two minerals are very similar in relation to the traditional separation processes. While the deposits which have been treated in Australia in the past have had only low levels of chromium present, many of the newer deposits contain much higher levels of contamination and, thus, there is an increasing need to develop robust processes to separate chrome spinel from the ilmenite. Flotation, which is a unit process with the potential to solve this problem, has surprisingly received little attention for this application. The literature suggests the research effort to characterise the general flotation properties of chromite (chrome spinel with high chromium content) has been extensive and a substantial amount of data is available. However, the problem of separating a small amount of chrome spinel from a large amount of ilmenite requires a different approach to that from separating chromite from siliceous gangue, which has been the main commercial focus of chromite flotation in the past. Much of the work done has been fundamental in nature and the results obtained are fairly inconsistent, as is the testwork completed at batch and pilot plant scale. While these inconsistencies have been attributed to the variable composition of the mineral, there is little evidence supporting this premise. Just as chrome spinel and ilmenite have similar physical characteristics, the flotation response of both minerals is also similar. This paper reviews the literature relating to the flotation of chrome spinel and presents a considered approach to the development of a robust flotation method to separate chrome spinel from ilmenite.

Jan 1, 2001

By Zamel GI

The utilisation of fossil fuels, including coal (of which Australia is a large producer and exporter) is a significant contributor to the emission of greenhouse gases. Methane gas, formed during the coalification process, is present in coal seams to varying levels depending on the rank and depth of the deposit. This gas usually escapes to the atmosphere during mining operations without prior conversion to C02 or utilisation as fuel. The quantity of methane released can represent from less than one percent to more than five percent of the carbon content of the coal mined. Per unit of carbon, methane has a greenhouse impact many times that of C02. The emission of uncombusted methane to the atmosphere can therefore represent a greenhouse impact of similar porportions to that of the CO2 formed by combusting the mined coal. However, greenhouse emissions from coal can be minimised by collecting the coal seam methane and converting it to water vapour and the less damaging form, CO2. If such conversion is carried out while performing useful work, the methane can further reduce greenhouse emissions by displacing other fossil fuels. Technology has been developed to allow coal seam methane gas to be economically collected in a pure form, uncontaminated with air. This pure methane can be used to supplement natural gas supplies, to generate power or for the production of chemicals or substitute transport fuels. By collecting and utilising coal seam methane, the greenhouse impact from the mining and use of coal can be minimised, with significant reductions possible in the case of gassy deposits.

Jan 1, 1989

The Ranger Project Area covers 78.6sq km and is approximately six km east-west by 14km north-south (Fig. 1). The area is known to con- tain two uranium orebodies, Ranger No. 1 and No. 3, two uranium occurrences, Anomalies 4 and 5 and three significant radon anomalies, Ranger 18, 19 and 48. The Ranger No. 1 and No. 3 Orebodies con- tain approximately 120 000 tonnes of U308 in highly chloritised metasediments of the Lower Proterozoic Cahill Formation. The orebodies occur as suboutcrop and exhibit significant radiometric anomalies. These occur within approximately 400m vertically of the projected unconformity with the sandstone of the Middle Proterozoic Kombolgie Formation. Oxidised and reduced uranium minerals occur in quartz-rich schists containing variable muscovite, chlorite and sericite and in the chloritic matrix of chert breccia. Secondary uranium minerals namely saleeite, metatorbernite and gummite associated with earthy iron oxides occur from the surface to 50m depth in No. 1 Orebody and up to 80m depth in No. 3 Orebody. Below the oxidised zone, uranium occurs as pitchblende finely disseminated throughout sequences of quartz muscovite chlorite schist up to 150m thick and as open space fillings in zones of structural deformation. The uranium-bearing schists directly overlie up to 300m of dolomite and magnesite containing minor interbedded schist units and are themselves overlain by approximately 2 000m of more micaceous schists of the upper part of the Cahill Formation. Regional metamorphism has occurred to at least amphibolite facies and has been followed by retrograde metamorphism to a greenschist facies equivalent. The metasediments are intruded by granitic pegmatites and dolerites. Uranium is associated strongly with chlorite of which there are at least five textural varieties. Not all of the various generations of chlorite have associated uranium. Graphitic schist horizons occur which are often less than one metre thick and discontinuous. These are best developed at the base of the quartz chlorite schist sequence where uranium grades up to 1 000ppm U may extend for several hundred metres beyond the main ore zone. Uran- ium is not common in the carbonate sequences and only occurs in chlorite segregations in disrupted zones. The unoxidised ore contains sulphides, mostly pyrite, which are low in abundance (

Jan 1, 1984

As an environmental "pollutant", noise is different. For one thing, it is localised (as opposed to transfrontier) and, for another, relatively low levels can trigger very strong human reaction. The reactions, which are annoyance-based, range from mild to violent and do not always correlate well with the levels experienced. This paper draws on technical aspects of noise to consider control and control principles and balances them with the subjective nature of the perceptions and reactions. It is critical to bear in mind that health effects resulting from noise are secondary to the primary human reaction. It is also important to appreciate that annoying noise levels are usually well below those which cause hearing loss. Large mines tend to be remote from cities and towns and the country surrounding such mine sites is often inhospitable. In general, residences near large mines are committed for use by mine personnel and annoyance from mining noise would be rare. Noise problems at long term operations are often a result of secondary activity or land use. As a pioneer mining community develops, secondary and service industries may be established and a township created. With changes in way of life, the perception of problems also changes. Therefore, it is never too early to plan for noise abatement, particularly because noise is only one of a number of environmental and community concerns. Ihny environmental problems are associat- ed with development or expansion of smaller open cut facilities such as hardrock quarries. There is an ever-present need to reduce product cost by mining or quarrying deposits close to the end user and many local authorities have to operate quarries for undertaking their civil engineering responsibilities.

Jan 1, 1987

Selective leach analytical techniques applied to surface geochemical samples in the search for deeply buried mineral resources gained popularity in the late 1990s. Several commercial assay laboratories introduced their own selective leach methods, adding to the few established commercial methods at that time. Many of these laboratories promoted their methods with orientation data showing favorable responses to both precious and base metal mineralisation, concealed beneath extensive thicknesses of overburden. However, many explorationists remain confused about the utility of these geochemical methods. This confusion is due primarily to the lack of objective orientation surveys over significant mineralisation, comparing all commercially available selective leach methods and to the lack of a creditable theory explaining the formation of these selective leach anomalies. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. An orientation survey was designed to fill the first void û an objective survey over significant mineralisation. With the help of 17 mining companies and assay laboratories, an orientation survey was conducted over five significant covered gold deposits in Nevada, USA , representing over ten million ounces of gold. Hopefully the results of this survey will help provide fuel for those working on the second void û a theory to adequately explain the formation of these selective leach anomalies.

Jan 1, 2008

By Torrance AC

A joint research programme conducted by BHP Central Research Laboratories and Du Pont Wesfarmers Pty Ltd examined the effect of the size of cast primers on the run up and steady state detonation veloci- ties of ammonium nitrate based explosives as a function of blasthole diameter. Both continuous and point to point velocity of detonation meas- urement techniques were used. The field trials examined a number of the Du Pont HDP series of primers in conjunction with ANFO, emulsion and watergel explosives. Results indicate that the run up velocity of 187mm diameter ANFO charges is negligible using cast primers as small as 150g. owever, emulsion and watergel explosives did exhibit run up in both 187 and 311mm diameter blastholes, independent of the size of primer. This could last from 7 to 10 blasthole diameters.

Jan 1, 1988

By Li T

Mining of the southern 1900 copper Orebody presented a challenge due to the complex geology, geometry and simultaneous extraction of the nearby lead/zinc/silver orebody. An integrated and co-operative approach was adopted, involving geology, geomechanics, mine planning and production personnel. Successful extraction of the first 1900 Orebody stope, T496, together with the extraction of the first two lead/zinc/silver panel stopes in the immediate hangingwall of the 1900 Orebody stope was achieved as a result of this approach.

Jan 1, 1995

By D R. Swinbourne, Y H. Yang

Calcium ferrite slag has gained prominence in the copper smelting industry over the last decade due to the emergence of continuous converting as an established technology. As smelters move towards processing which is higher in intensity, more efficient and more environmentally acceptable, its use is likely to increase because it has technical advantages over conventional iron silicate slag, which include a higher magnetite-holding capacity, lower copper losses to slag and a lower viscosity. Calcium ferrite is currently the converting slag of choice in the Mitsubishi process at operations in Japan, South Korea, Indonesia, Canada and Australia, and in the Kennecott/Outokumpu flash converting process in USA. However, users of this slag have experienced problems in containment due to its highly corrosive nature and low viscosity. As use of this slag becomes more widespread the containment problem will assume greater importance. Consequently, work has recently been carried out to establish the mechanism of refractory attack and devise means to retard it. This work will be critically reviewed in this paper.

Jan 1, 2000