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By G Kluck, N Stoitis, D R. Seaman, R A. Lauten

The presence of clays, in particular clay slime, may complicate many mining operations. Clay slime particles may possess a negative or positive charge depending upon the pH in the process and their presence may lead to reduced recoveries in flotation processes. It is assumed that slime particles may adsorb onto the surfaces of the minerals to be floated and by doing so, reducing the efficacy of the flotation chemicals. In this work it is shown that addition of a small amount of dispersant, either a polyacrylic acid or an anionic polyphenolic polymer, increases the recovery of copper and gold, both in laboratory trials and in plant testing of an ore with high clay content. Measurements of adsorption isotherms reveal that the tested dispersants show preferential adsorption towards the clay minerals present, suggesting that the improved recovery upon dispersant addition occurs by prevention of attachment of clay slime particles onto primarily chalcocite but also chalcopyrite.CITATION:Seaman, D R, Lauten, R A, Kluck, G and Stoitis, N, 2012. Usage of anionic dispersants to reduce the impact of clay particles in flotation of copper and gold at the Telfer Mine, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 207-214 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By G J. Corbett

Magmatic-related low sulfidation hydrothermal ore systems at plate margins exhibit distinct spatial and temporal zonations which can be used to aid mineral exploration and development. Low sulphidation systems at all crustal levels exhibit the same paragenetic sequence of events: early breccia formation, followed by quartz - secondary feldspar sericite/illite veining, then mineralisation, and final argillic overprint. This sequence of events is interpreted to reflect the initial emplacement of melts at high crustal levels, and the progressive cooling of that melt and release of magmatic constituents into a circulating hydrothermal system.   Low sulphidation systems in the south-west Pacific region exhibit a vertical zonation in deposit types: from porphyry copper-gold at deep levels, quartz-sulfide-gold at mesothermal to deep epithermal levels, carbonate-base metal gold at mainly epithermal levels, and epithermal quartz silver-gold at shallow levels. It is interpreted that the characteristics of each of these styles of deposits is produced by mixing with circulating waters of different physio-chemical compositions.

Jan 1, 1995

By S H. Begg

"*This is an abstract only*Most technical and economic analyses are performed to reduce uncertainty to help make decisions. Decision-making is about ranking alternatives - rarely are precise predictions required, if even possible. This simple observation has profound implications for modelling approaches, how they deal with uncertainty and the reliability of information provided by subject matter experts.CITATION:Begg, S H, 2013. Some reflections on uncertainty, decisions, models and people, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013, pp 3-6 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 29, 2013

By A G. Greenwood

Research into cemented rock fill at Mount Isa Mines Limited since 1992 is described. The key mechanisms controlling segregation during stope filling with cemented rock fill are described and include the gravity flow mechanism which is described in detail. Examples are provided to demonstrate these mechanisms. Comparisons are made between Mount Isa MinesÆ cemented rock fill and slurry-based cemented rock fills. Recent backfill stability modelling using a three-dimensional finite element program is described.

Jan 1, 1998

of the multitude of physiographic problems of immediate interest in volcanic terranes, it is the origin of the magma forming the magnificent volcanoes that is perhaps the most mysterious. Unlike anywhere else on earth, the possible locations of magma production beneath the convergent margins are strongly limited in depth and areal extent. Yet the exact process by which magma is produced still stands elusive, even in light of tremendous gains in analytical and physical insight. The principal aim here is to discuss some of what has been revealed about the physics and chemistry of the origin and evolution of island are magmas.

Jan 1, 1987

The preconcentration of uranium ore by radiometric ore sorting at Mary Kathleen Uranium Ltd. is described. The operation of the ore sorting machines is discussed in detail and performance results obtained with the existing system are presented.

Jan 1, 1978

By P Knights, M S. Kizil

Truck/shovel operations constitute 50 - 60 per cent of the cost of open pit mining operations. Mining companies, therefore, are constantly seeking to close the gap between actual truck/shovel productive capacity and maximum potential truck/shovel capacity. This paper analyses the performance of a mixed truck/shovel fleet in an open cut coal mine in Australia. It analyses operating delays, and proposes a novel graphical means of determining truck-limited or shovel-limited operations. A goal seeking algorithm is advanced in order to maximise truck/shovel match factors (MF) and hence optimise fleet productivity.

Sep 26, 2011

The published safety policy of Mount Isa Mines Limited, together with details of the organisation and control techniques adopted by management to pursue an active safety programme within the company, is presented. The importance of communication by management through the organisational hierarchy and procedures instituted to ensure rapid and concise feedback on safety concerns are detailed. The paper also describes the role of the occupational health department and safety committees in assisting management to monitor the safety effort of supervisors and employees. Current safety performance levels are tabled together with details of some aspects of the programme on which safety effort will be concentrated in the future.

Jan 1, 1975

By McManus D

Situations where in-pit bench stripping methods are favourable are introduced. Examples from Peak Downs Mine are used as a guide to the range of methods available.A number of geological and geotechnical conditions adverse to successful in-pit bench stripping are described. In all cases bench, floor, and/or final lowwall instability can develop and compromise the economics of extraction.

Jan 1, 1992

By Longworth C. R

This paper descrioes a case history of a coal mine which developed un'tahle roof conditions due to mass sliding of the overburden strata on a claystone band within the coal seam. The sliding is believed to have been initiated by stress relief associated with the removal of overburden alongside the entry portal of the underground workings. Once in motion, the roof block was kept moving by bulking due to roof collapse in the normal underground goafing operations. Control measures in the form of an earth and rockfill buttress against the entry portal and a sequential mining plan to create goaf areas alongside the entry portal have been initiated to attempt to limit movement. The operation has been continually monitored and a gradually decreasing pattern of movement is being re, orded.

Jan 1, 1981

By Artone E

screening equipment installed in e Hamersley Iron operation is described, and tails of operating parameters and screening - Iia in use are given. Tests were carried out on full-size reens in the operating plants to study the Meets of mat aperture size, feed size distri 1,ution, feed rate, screen speed and throw, angle of inclination, and feed moisture content n screen performance. Sampling equipment was signed so that undersize samples could be htained from various locations along the length of the screen, thus providing information pout the quantity and size of particles passing òhro gh the screen at any point. Conclusions derived from the testwork and relevance of these to the Hamersley Iron aeration are discussed.

Jan 1, 1984

By Mance G

Today there are many different techniques of soil remediation used in Australia and throughout the world. This paper considers the thermal desorption remediation technique and, in particular, the application of high temperature filtration to the process. The thermal desorption technique involves the treatment of hydrocarbon (oil, petrol, etc) contaminated soil. The process involves heating the soil in a retort or kiln to drive off the volatile organic contaminants. The exit gas stream from the retort is subsequently passed through an after burner to thermally oxidise the hydrocarbons. This technique produces soil and combustion gas streams which are free of hydrocarbons. Due to the heating and agitation of the soil within the retort, soil particles become entrained in the hot gas stream. To avoid the blockage and fouling of the system's interim ductwork and the afterburner, high temperature filtration technology has been applied to remove these soil particulates without cooling the gas Stream.

Jan 1, 1995

By Cornwell P. J

The Pajingo ore bodies consist mainly of auriferous quartz veins hosted by a suite of hydrothermally altered andesitic pyroclastics, volcanics and epiclastic sediments. Scott lode, the main economic deposit in the area, lies in a zone of major structural disruption and contortion. High grade gold and silver mineralisation is selectively mined by open pit methods. Standard grade control techniques and extraction methods were adapted to minimise mining dilution and to maximise metal recovery. Basic blending of grade ranges at the crusher has produced an average 10 gram/tonne gold head grade. The estimation of ore reserves calculated by both standard polygonal and geostatistical methods proved acceptable. Mineable reserves when compared to in pit reserves defined by blast hole drilling, indicate a decrease in tonnes and an increase in the grade resulting in an acceptable comparison of the total ounces of contained gold. The ore reconciliation of mined against milled ounces indicates that both ore reserve and grade control models underestimate the metal content in the orebody. Sampling techniques are being examined in an attempt to reduce this discrepancy.

Jan 1, 1989

Many of the discrepancies that appear when comparing the results of reducing machinery are due to the nature of the materials reduced and the conditions under which they have been treated. It is therefore necessary that manufacturers should employ standard materials in their tests that sufficiently approximate the substances to be ultimately treated if the information is to be of any value to the purchaser. Another advantage to be gained by employing universal standard materials is that by their means one is enabled to compare the relative values of different types of machines. At present much of the data meted out to the public is insufficient to enable them to judge fairly. Of course the best test would be to send some of the stone tor which the machine is required, to be treated by the various crushers in the market that are likely to be suitable for the purpose, but this is not always possible. It would not take long to become accustomed to judge of the value of a machine for a specific purpose if it was guaranteed to work a certain quantity of some standard rock, even if that standard were not identical with the material to be treated.There are many points to be considered before selecting a machine, such as the size of the rough stone it will take, the size to which it will reduce it the proportions of various grades made when crushing to pass through a given mesh the form of the delivered particles the time taken to treat a+ certain quantity the horse-power required to drive the machine, both when loaded and unloaded whether constructed to crush wet or dry the wear and tear of the machine its total weight and weight of the heaviest part the cost of machine what attention it required whether the wearing parts are readily replaced, and several other points common to all machinery. 'When considering these varying quantities, we can tell at a glance certain machines that are suitable for a particular sort of work, and can then compare those belonging to the same class, thus avoiding errors made purposely or through ignotance by persons interested in different machines, who frequently compare machines originally constructed for.

It is a commonplace of our industry that prices of most minerals have been historically weak during the 1980s. The International Monetary Fund's index of prices of metals fell 25 per cent between 1980 and 1982, rose slightly in 1983, and has since fallen further. In December last year it was 37 per cent below its 1980 average. The few temporary exceptions to the mineral industry's malaise highlight the excess capacity, which largely explains the weakness of prices. The industry has painfully come to recognise that more satisfactory prices will not be restored until supply capability and demand move back into better balance. Mine capacity was installed in the expectation of much faster growth of demand than has occurred. For a variety of reasons mine and plant closures have been insufficient to restore equilibrium to the market-place. The industry may, therefore, have to resign itself to continued weak prices for some years more, at least by the yardstick of the 1970s. Growth rates of demand have slackened off in line with economic activity, and in response to continuing substitution and technological improvements. To the extent that the recent weakness of oil prices stimulates the industrial countries' activity, demand for non-fuel minerals may grow faster than most forecasters now predict. It is, however, much too early to say how long the weaker oil prices will persist, and even more difficult to estimate their probable effects. In typical post-war business cycles the usual response to recession was to batten down the hatches, and ride out the storm. Sooner or later, and probably sooner, demand resumed its previous trend path, and prices recovered. The market, in effect, bailed mines out of trouble; the more efficient could make attractive pre-tax profits whilst even the poor to mediocre could earn a satisfactory living. Prices rose at least as fast as general inflation, and in the early 1970s much faster. In retrospect those price rises of the early 1970s were historically abnormal but they did not appear so in the prevailing inflationary climate of the time. When the market failed in the early 1980s many of the hardest hit companies looked for scapegoats.

Jan 1, 1986

By Snowdowne J. B H

Rand Mines, Limited, located in Johannesburg, Republic of South Africa has recently completed feasibility studies which have lead to the initiation of two major coal strip mining ventures. A minicomputer based mine planning system was developed to perform the feasibility studies. The broad approach of this system is to utilise inter.-actively the specialist skills and interpretative abilities of mining engineers and geologists. This paper reports briefly on the outline of the system and at greater length upon certain aspects of its use.

Jan 1, 1977

By Jensen W. S

The Mount Morgan ore-body is intersected by dykes to such an extent that it presents peculiarly difficult problems in extracting ore. These are shown on Plates Nos. LXVII. and LXVIII. Besides ,these dykes there are innumerable "heads," which alsoare a source of danger. Falls of ore occurred in the end of the year 1908, resulting in serious loss of life to miners employed. It was decided, after an exhaustive inquiry, to change the entire system of mining from the" flat backed stope system" to the" square set sectional system ," the latter being more flexible and allowing bad ground to be cut out from a safe position; but it became evident that, whatever system was adopted, there would be more or less danger unless all the dykesand heads known were picked up, and their continuation plotted on a special set of plans on which the general scheme of stoping could be plotted from time to time as work progressed. It is worth while pointing out that, in every other branch of engineering, it is usual to design the work, and that only in mining engineering has it been common to do the work first and plot it down afterwards.The term "sectional analysis" is familiar in most branches of engineering design, and as applied in this paper to mining, may not bear the same meaning, but the general purpose is analagous, and there is no other term used.

Jan 1, 1911

Throughout 1992 Pasminco conducted field trials of the Mobile Miner MM130 at Broken Hill. The goal was to develop the machine to achieve acceptable reliability and establish production rates.

Jan 1, 1993

In both exploration and mining, the laboratory is often seen as a cost rather than a profit centre. The aim in most mining companies is to increase profits by reducing costs, so the budget for the laboratory is under constant pressure.There is another option; to see the laboratory as the brain of the operation. By lifting the status of the laboratory and treating it as a profit centre, mine costs may be reduced in other ways, e.g. reduction in milling costs. This change of status will require investing more capital in better equipment, more training for employees and more employees to carry out project research.There are many examples of major costs being incurred because of inadequate laboratory work. Conversely, by spending more money on laboratories and their activities, overall costs can be reduced or profits enhanced.

Jan 1, 2002

By Brasnett TC

A wide variety of problems are encountered on a day to day operating basis in the Isa Mine Concentrators. These vary from complex textural problems in the lead-zinc concentrator and their subsequent effect on grinding and flotation to scheduling of converter slag treatment in a chalcopyrite concentrator. With the advent of process control, metallurgists need to specialise and keep up to date with technology improvements. This paper will attempt to describe the significant problems'faced by a Metallurgist û Control.

Jan 1, 1978