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Railway cuttings require the highest care in design and construction, as the pro- bability of failure concept does not allow any risks to be taken with hundreds of lives being dependent on continued stability. The usual geological influences on stability such as bedding dip and faulting are often discus- sed, but other major problems may come from the presence of sheet joints, cross joints differential weathering and seasonal or daily changes of ground water level. The design of rail cuttings has taken little note of the problems imposed by cons- truction methods, and low cost quarrying methods may seriously weaken a designed shape. The presence of berms and drainage ditches is often difficult to achieve as blasting imposes cumulative stresses and jointing on rocks. Contractors face difficulties in bidding extensive rock cuttings as variations in rock properties are often concealed and overshoot- ing the toe of a batter can easily occur. Modern blasting methods offer some solutions, but the best guide to safe successful cuttings is extensive investigation and the continued involvement of engineering geology at the stages of feasibility, design, construction and maintenance. Two case histories show the influence of folding, faulting and construction methods in the case of slope failure and slope stability.

Jan 1, 1979

By Hunter GW

This paper gives an account of the filling system at Mount Isa from surface fill production to stope discharge underground. A brief explanation of the surface facility and reticulation is given prior to the discussion on aspects of underground reticulation. These include fill hole types, pipe and breastplate installation, wear characteristics, etc. The different types of fill and their respective applications is mentioned as a prelude to a general overview of the mining considerations associated with fill placement and its role in the long term planning strategy at Isa Mine. Some practical aspects of stope preparation and filling procedures are outlined for the various stoping methods. Finally a brief outline of future fill developments is given.

Jan 1, 1982

Delivered by K. B. Gross at the First Ordinary Meeting of the Australasian Institute of Mining and Metallurgy, August 18th, 1952.Mr. President, Ladies and Gentlemen:Confronted with the task of reviewing the progress of Mount Isa Mines Limited, since the inception of the Company 28 years ago, I soon found that effective coverage was a task beyohd me, if I were to confine the address within the limits of time allowable. Faced with the alternative, a summary, that could only fail to -do justice to the subject, I turned elsewherl? for inspiration and found it in Chester Wilmot's book "The Struggle for Europe". Those of you who have read this masterly contribution to the literature of World War II will recall that he takes us, most dramatically, behind the scenes and we learn of the thoughts and ideas that were uppermost in the minds of both allied and enemy leaders at times when decision's that profoundly influenced the course of the war were taken. I felt I could safely follow this rather novel approach to my own problem. Strengthened by the realisation that the technical achievements of the Company have largely been covered over the years, and that the results of our labours are mainly here before you, I have attempted to liven up my modest canvas by going behind the scenes, and have sought to deal with ideas and the reasons for important decisions, rather. than to embark upon a purely descriptive essay.If then, you will bear with me, we shall skip back through the years to the days of struggle that our President's address has so aptly covered, and find that one man's ideas and faith stand out beyond all others. W. H. Corbould must always be credited with having founded the enterprise, for he correctly appraised the potential of the struggling prospect and foresaw what could be done, despite the handicaps of geography, climate and need for heavy expenditure.

Jan 1, 1953

The introduction of large diameter holes to underground mining has provided the first opportunity to apply near spherical charges in production scale blasts instead of the convent- ional long cylindrical charges generally used in stope and pillar mining. A modified version of the cratering prin- ciple was applied in the blast design in extrac- ting ore across a horizontal area of a stope or pillar. The new rock breaking technique has developed into the Vertical Crater Retreat (VCR) mining system and eliminated raise boring, slot cutting and dilution of the ore by back- fill material. Furthermore it has reduced labour and time requirements thus becoming not only a low cost method of mining but the safest method of underground mining known today. Exceptionally fine muck is provided with a minimum of damage by blasts to walls and re- treating backs of the stope or pillar. The VCR method can also be used for drop- raising, and for the excavation of underground cavities for almost any purpose . The proper explanation of the breakage mechanism of the near spherical charges opposite to the cylindrical charges yet to be found. The mining industry has quickly recognis- ed the value of the VCR mining method which is being adopted by an increasing number of mines

Jan 1, 1978

By Katom M

Each of the two 32 feet diameter Semi Autogeneous Grinding (SAG) mills at Ok Tedi's copper and gold concentrator was treating at best 1500 tph at about 65 per cent mill availability in 1988. The process was effectively unmeasured and used manu

Jan 1, 1997

Mixers are commonly used for the transfer of oxygen in gas-liquid-solid reactions in minerals processing. The process rate is usually controlled by two steps: gas-liquid mass transfer and reaction kinetics. Some examples are described along with the factors used for analysis of the mass transfer design problem. Typical oxygen rates and appropriate types of aeration systems or mixers are reviewed. The commonly used Rushton turbine has limitations in a number of mineral processes. The development and characteristics of the LIGHTNIN A315 axial flow gas dispersion impeller are described. Some practical examples which highlight its advantages are briefly described.

Jan 1, 1992

The first thing to be aware of is that the warming effect of carbon dioxide is strongly logarithmic. Of the 3¦ that carbon dioxide contributes to the greenhouse effect, the first 20 ppm has a greater effect than the following 400 ppm. By the time we get to the current level of 384 ppm, each 100 ppm increment will produce only about 0.1¦ of warming. With atmospheric carbon dioxide rising at about 2 ppm per annum, temperature will rise at 0.1¦ every 50 years for the next couple of hundred years before the effect becomes minuscule. The warming of the 20th century, as the Earth came out of the Little Ice Age, was a consequence of short, high-amplitude solar cycles. A number of solar physicists have predicted that the next solar cycle, Solar Cycle 24, will be quite weak. Based on the correlation between solar activity and the EarthÆs climate, a temperature decline of 2¦C is predicted for the mid-latitude regions over the coming decade, equating to the experience of the Dalton Minimum. Anthropogenic warming due to carbon dioxide will not ameliorate this temperature decline. Increased atmospheric carbon dioxide is wholly beneficial due to itÆs fertilisation effect. Efforts to inhibit Australian carbon dioxide emissions are exactly wrong in science.

Jan 1, 2009

By He BQ

Static attachment of bubbles to solids is contrasted with dynamic attachment in flotation cells. The times of contact during particle-bubble collisions in dynamic attachment are compared with the induction time determinations and the kinetics of thinning of the liquid films separating solids and bubbles. The thinning is examined mainly in terms of electrostatic and dispersion (van der Waals) contributions to the disjoining pressure existing in the films. The local heterogeneity (on a molecular scale) of charge distribution invariably present at all interfaces (even at conditions of zero zeta potential) calls for some means to minimize possible electrostatic repulsions which arise when the electrical double layer at the air-bubble interface begins to overlap that present at the solid surface, on encounter between particles and bubbles. It is postulated that dipoles of frother molecules, owing to their ability to "flip over" (polarise), replace localized electrostatic repulsion by attraction within fractions of a milli- second, as long as the structure of the frother molecules is sufficiently "bulky" to maintain diffuse films (of mixed collector-frother) at the air/liquid interface of bubbles. The relaxation times of dipoles (signifying their "flipping over" ability) have to be shorter than the collision times between particles and bubbles for particle-bubble attachment to be facilitated under dynamic Conditions.

Jan 1, 1984

By Thompson M

The humble gabion basket is to mine development what the light bulb and safety pin are to eir-ryday life. Gabions provide a flexible, easy to assemble and cost efficient solution for "101" mine and civil engineering development applications.In some instances gabion baskets are still efficiently in use after many years of faithful, maintenance-free service. In other situations, the baskets have been demolished or made redundant within days, either having served their temporary usefulness or negligently destroyed by the operator of heavy equipment. Either way, the gabion basket must surely rate among the top 10 cost efficient engineering construction materials.

Jan 1, 1994

By Jefferson CW

Middle-to-Late Proterozoic stratigraphy and metallogeny in the eastern part of the Canadian Cordillera and in South Australia are strikingly similar. In both areas, thick, predominantly shallow-water strata and their contained mineral deposits can be divided into three sequences (A, B, C) that record episodic and prolonged continental rifting. It is proposed that Adelaidean strata of Australia were deposited adjacent to Belt-Purcell, Mackenzie Mountains and Windermere strata of the Canadian Cordillera within an epicontinental trough of a "Hudsonia" regacontinent. With the final rifting of this trough, the paleo-Pacific ocean was born. By Early Cambrian time, Australia- Antarctica was on the trailing "east" side of the nascent megacontinent, Gondwana, and was being modified on the "west" by accretion in the Pan-African event. North America, more or less surrounded by trailing edges at this time, was analogous to the Cenozoic African plate. This hypothesis accommodates the available paleomagnetic and radiometric data. It has implications for pre-Pangean plate tectonics, paleogeography, and the predictive metallogeny of both areas.

Jan 1, 1987

By T Lancaster

The Mount Gordon operation, consisting of the Esperanza open cut mine and the unique Mount Gordon Ferric Leach processing plant, is operated by Western Metals Copper Ltd at Mount Gordon, 125 km north east of Mt Isa. The processing plant treats predominantly the secondary copper sulphide minerals, chalcocite and covellite. The gangue consists of massive pyrite and a range of silicified siltstones. The processing plant utilises a conventional single stage SAG/cyclone milling circuit, followed by low-temperature/low-pressure autoclave oxidation to produce copper in solution. The pregnant leach solution is treated via conventional SX/EW technology to produce copper cathode. Currently the plant is operating at a nominal production rate of 48 500 tpa copper. The Mount Gordon Ferric Leach technology is the worlds first integrated pressure leach/SX/EW process to be used to treat copper sulphides on a full plant scale. In the last six months, July to December 2001, the plant has emerged from a two-year postcommissioning phase to achieve steady state operation. This has been characterised by high plant availability and consistent production performance in excess of the name plate capacity of 45 000 tonnes. Production rates will continue to increase over the next 12 months to over 50 000 tpa via a planned process of incremental improvements. The pressure leach circuit has consistently achieved availabilities exceeding 95 per cent over the past 18 months. Notwithstanding this, the leach circuit still has a much greater requirement for planned maintenance than SX/EW. For much of the Mount Gordon processing plantÆs operating life, the leaching process has constrained production. Recent developments arising from detailed mass and energy balance modelling have now significantly improved leach capability, resulting in the plant bottleneck being shifted to electrowinning. In order to balance the capabilities of the two circuits however, the surge capacity between leach and SX/EW was increased substantially. This effectively de-coupled the higher capability but lower availability leach circuit from the lower capability but higher availability SX/EW circuit. As a result, electrowinning utilisation has increased to in excess of 98 per cent, which is reflected in a higher overall plant throughput.

Jan 1, 2002

By Penttila V

The Paleoproterozoic Hitura Ni-Cu deposit in western Finland is in an ultramafic igneous complex composed of two subvertical plug-shaped bodies embedded in intensely migmatised felsic gneisses. The ultramafic complex is not far from a north-south trending graphitic and sulphidic gneiss zone interpreted to be a primary sulphide-graphite unit in the metasedimentary sequence. The sulphide accumulation exists as a zone parallel to the contact of the northern ultramafic body. The ultramafic rock types, now mainly serpentinites, have primarily been olivine adcumulates in the core grading to olivine orthocumulates and pyroxenites towards the margins. Coarse-grained felsic pegmatite veins injected serpentinite where they now exhibit prominent zoned alteration rims of chlorite, antophyllite and talc. The serpentinite core of the body was primarily an olivine adcumulate derived from a tholeiitic or high-Mg basalt parental magma with about 11 wt % MgO. Metamorphism and alteration have totally changed the igneous mineral compositions and the rock types are serpentinites (from olivine adcumulates), ambhibole-bearing serpentinites and amphibole-chlorite rocks (from pyroxenites). As the result of CO2 alteration talc is an accessory mineral throughout the serpentinite. Like silicates, also sulphide minerals are altered. In the core of the body the low-grade sulphide dissemination still reveals primary igneous interstitial forms. The core sulphides are now mackinawite, pentlandite and valleriite instead of primary igneous pyrrhotite and pentlandite derived from Mss. At the marginal zone the heavy dissemination and net-textured sulphides display pyrrhotite-pentlandite-magnetite intergrowths with magnetite films along cleavage of sulphides, mackinawite in pentlandite and exsolution textures of different low-temperature pyrrhotite phases as the result of alteration processes. Mechanically weak rocks, complicated structures and textures of the ore, magnetite and mackinawite intergrowths in pentlandite and readily-floating MgO silicates cause problems in exploitation of the deposit. Solution to problems come from selective stoping, three-step classification in grinding, froth-washing technique and on-line process control based on ore type determination from process data using an expert System

Jan 1, 1996

The evolution of the Oaky Creek mining complex provides a good example of the mining cycle in practice. Oaky Creek has been innovative in its choice of mining methods, with virtually the full range of coal mining methods having been used as workings have progressed down dip. The history of the mine is traced through its development (and ownership changes), progressive selection of mining methods as depths of cover to seams being mined have increased, and rehabilitation. This allows the different mining methods to be described and illustrates the concept of æwall-to-wall miningÆ.

Jan 1, 1998

By S Rice, A Midlin

Many of the stacking and reclaiming machines employed in the mining industry today are operating in ways that were never envisaged in the days before they were commissioned, with greater throughput, increased annualised operating hours and load cycles well in excess of their original specification requirements being the norm. In many cases these machines were supplied prior to the widespread use of finite element modelling or, in the era when such software became commercially available, those supplied designed using simplified and/or coarser meshes than would be employed today. With many of these machines being expected to operate for many years to come, it is important that their ongoing reliability be maintained and their operational limits understood. In this paper, a case study is used to outline the method required for estimating the fatigue life already consumed and the likely real life left in a machine. By reference to the machineÆs prior operating history, the use of strain gauges in the field and the development of finely meshed finite element analysis (FEA), a coherent picture of the machineÆs operational state can be generated and then investment/maintenance decisions made to ensure continuity of machine operation.

Jan 1, 2007

By Saint-Smith J. C

The anode, tank house and wire bar plant and operations are described with particular reference to those features of design and methods which are characteristic of this refinery at its inception.Reference is also made to auxiliary equipment, transport and materials handling facilities.The work of commissioning the plant late in 1959 is discussed and comment is made on the organisation of construction and origin of the equipment.LOCATION OF PLANTThe site chosen for the copper refinery is on level ground adjacent to the junction of the Mount Isa and the main north-south railway lines at Stuart near Townsville, Queensland. Blister for refining is received by rail from Mount Isa. Refined products are taken 10 miles by road to Townsville Harbour for shipment to other Australian ports or overseas, or despatched by rail direct from the plant.Adequate room for expansion was provided to cover copper refining and any associated industry. The layout of future extensions was planned and space reserved for them before detailing the original units of the main refinery.The initial plant also provides convenient storage facilities and is laid out to derive the greatest benefit from prevailing northerly breezes during the humid tropical summer.As far as possible, the working areas are located so that the prevailing winds cool them as they traverse the buildings.These factors are of very great importance since this is believed to be the only copper refinery in the tropics operating with all white labour and in any case the Company set out to provide the best possible conditions for its operating personnel.

Jan 1, 1961

By Palmer G, Dennis R, Clark A

The Ravenswood Mine in North Queensland is the first gold mine developed by Carpentaria Gold Pty Ltd, a wholly owned subsidiary of MIM Holdings Ltd. Carpentaria Exploration Pty Ltd began exploration at Ravenswood in 1978. However initial exploration of the main gold producing area (Buck Reef East) commenced in March 1987 when exploration rights to four key leases were secured. A rapid, co-ordinated exploration and development program produced gold from a heap leach operation nine months after the first costeans were dug at Buck Reef East. To treat higher grade ore found at depth in the Buck Reef East pit and the metallurgically more difficult Buck Reef West ore, a carbon in pulp plant was commissioned in May 1988. The mine is currently producing at a rate of approximately 40 000 ounces of gold per year. Ore at Ravenswood is hosted by hydrothermally altered diorites and tonalites of the Ravenswood Granodiorite complex. Alteration is controlled by planes of permeability formed by joints, shear zones and dilational breccias. The complex orebody geometry resulting from these controls required very detailed surface and drill exploration for adequate definition. Carpentaria's need for early cash flow meant that economic, mining and metallurgical considerations governed choices of exploration techniques, program timing, material and data collected. The initial reserve of 1.1 mt @ 2.87 g/t Au was defined by sectional polygonal methods. Grade control is based on geologic mapping and blast hole or channel sample assays. Ore is batched through the crusher and sampled to monitor grade control and mining performance. Minimal dilution has occurred. Gold content is greater than predicted by the reserve. Sprinkling of heaps commenced in November 1987. Changes have been made to the pad design and to the method of heap construction. Heap leach ore is treated at a rate of 400 000 tpa.

Jan 1, 1989

By Carter J. P

A two year study into the effects of coal mining induced subsidence on cliff lines was undertaken by the Department of Mineral Resources with the support of a grant under the National Energy Research, Development and Demonstration Program. A new monitoring technique, using an Electronic Distance Meter and acrylic reflectors attached to the cliffs, provided safety for the surveyors and extensive and accurate three dimensional displacement data on the movement of the cliffs as they were being undermined. The study report included many graphs showing the measured vertical and horizontal displacements, differential subsidence, tilts and strains and included analysis of these movements with various parameters, such as, seam thickness, depth of cover and distances between the reflectors, longwall face and the edge of the chain pillar. Some of these graphs are presented in this paper and could be used, with caution, to predict subsidence movements around other cliff lines, after allowing for differences in geology and mining layout. A mechanism is suggested as an explanation for the observed high horizontal movements around the cliff lines. Sixteen percent of the overall lengths of cliffs that were undermined during the monitoring study fell and the contributions of various factors that appeared to influence the cliff falls are discussed. It is concluded that no single factor dominated as the major cause of the cliff falls and, often, many factors combined to cause cliff face instability.

Jan 1, 1992

By Kendall W. T C

This paper provides a brief overview of the history of the Chaffers Dewatering Project which was successfully commissioned in August 1993. Until the end of 1992 the `Superpit' and the deep mines of the Golden Mile had all been dewatered by a staged pumping system from the 28 level in the Lake View Shaft, which was removed at that time when the Lake View Mine was absorbed into the Superpit. Feasibility analysis had indicated that adaptation of oil industry technology offered the greatest potential for a low cost solution to the problem of dewatering the open pit and deep mines. A KCGM engineer and one of the authors visited the Jackson oilfields to look at the deep well pumping technology in use there in early-1991. In the final analysis a new dewatering station was established in the 23 level crushing station of the Chaffers Shaft using conventional plunger pumps, but the rising main was screwed 178 mm OD (7 inch) casing the suspended from the surface to a depth of 686 metres, and was installed using oilfield personnel and methods. Only the second installation of its kind in Australia, the project achieved the dewatering objective at about half of the capital cost of the more conventional approach and at lower operating costs as well.

Jan 1, 1995

By McQueen LB

The Water Board has been involved in the development and ipgrading of sewerage facilities in the Blue Mountains since 1980. In 1984 the Board prepared a report that dealt with the Blue Mountains Sewage Effluent Management study. Successive 3ovemments have been concerned about development in the 3lue Mountains and the effect this development is having on the luality of the streams flowing into the Blue Mountains National ?ark (presently up for World Heritage Listing).

Jan 1, 1993

By L M. Foster, J R. Kellett, G A. McMah

The Great Artesian Basin (GAB) contains one of the largest reserves of fresh water in the world. The volume in storage is enormous, being estimated at nearly 65 000 million megalitres (ML). Development of this resource, dominantly for the pastoral industry, began in the late-1800s and quickly accelerated. With exploitation of the resource, artesian pressures declined almost as rapidly. This loss of head is a result of the total discharge from the basin and much of this discharge is waste of water. The waste through uncontrolled bores and inefficient distribution systems still amounts to about 75 per cent of all discharge. However, the volume in storage has hardly been depleted. The major concern is the effect of withdrawal on artesian pressures. Due to the size of the Basin, the relatively flat gradients and low permeability, the movement of water through the aquifers is extremely slow and independent of recharge. Hence, the normal concepts of sustainable yield (ie discharge should equal recharge) cannot be applied to the Basin as a whole as travel times do not allow for the effect of recharge to be seen away from the outcrop areas within management timeframes. The large volume in storage, though, can provide an extensive buffer to the impacts of temporary water needs. This effect should be considered when assessing the acceptability of fixed life projects such as mines and the extracted volumes from their operations. Identifying a sustainable yield involves balancing the acceptability of the economic, environmental and social costs with the associated discharge and fall in head, to arrive at an acceptable balance.

Jan 1, 2003