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This paper describes a case history of using an integrated geochemical and hydrogeological approach to predicting solute transport from gold mine tailings in highly fractured volcanic terrain. Two modes of transport are identified, namely discrete fissure flow and diffuse seepage through the intervening weathered rock. A simple mass balance approach is used to predict concentrations at points of emergence because most of the seepage migration will be by way of the discrete fissures where advective transport will predominate. The mass balance method has been modified to allow for natural degradation of weak acid dissociable cyanide. The long term effects of diffuse seepage are also examined.

Jan 1, 1988

This is the time of year tor the presidential address, and with the present incumbent engaged in the coal mining industry, it will therefore come as no surprise to you that the theme of my address this evening is concerned with coal.There are other reasons for this apart from my contact with the coal industry. At present, coal is supplying considerable overseas revenue at a time when the remainder of the mining market is in a somewhat depressed state. That times will change goes without saying, if history is to be believed.However, so far so good for coal. My first reaction when The Institute indicated its wish that I be president for 1976 was to become deeply conscious of the honour bestowed on me.On consideration, I realized that very few past presidents have been intimately connected with the coal mining industry to the extent of indulging in it for lengthy periods as a full time occupation or, conversely, a part time interest for a long time. It also appears that not one had started their career in the industry. In my case, 'also, there were 8 very interesting years ,as a gold miner and metallurgist before commencing in coal.It therefore seemed appropriate to endeavour to discover ,why this should be so, as coal mining is now a very important part of a very important industry. What were the reasons why the industry took so long to emerge when there were ample reserves of easily accessible coal?Frankie and Johnnie in their bar room epic of the depression years concluded, and I paraphrase, that "their story held no moral, their story told no tale". If my story has such a message, it could perhapsbe construed as reinforcing the oft-repeated dictums, true or false, that "history repeats itself" or "man never learns".Coal mining is by far our oldest major Australian industry except for agriculture. Its history is almost as old as that of settlement:For various reasons, there has been a glamour associated with metal mining ventures which prob...

Jan 1, 1976

A four monthly period was analysed for each retreating longwall face which indicated that output increased from 1140 tonnes/day for Longwall 1, to 1620 tonnes/day for Longwall 2 and to 2090 tonnes/day for Longwall 3. An output of 2500 tonnes/day should be achieved from the new Longwall 4, largely due to the improved tailgate corner design and despite a continuing lump coal problem. The evolutionary trend is a feature of longwall mining; the evolution occurring both with mining and mechanical design at the colliery itself and with the longwall equipment offered by manufacturers. The trend is towards simplicity, increased strength and capacity, simplified maintenance and increase relia- bility.

Jan 1, 1976

The paper describes the geology, structure, stress, gas and strata geomechanical properties for Leichhardt Colliery and their reactions to mining.

Jan 1, 1986

Environmental considerations were key factors in the design of the Ranger Uranium Mines treatment plant. The mine is located adjacent to the Kakadu National Park and has an average rainfall of 1.6m per annum. Initially, no contaminated water or liquid effluents are to be released from the project area and thus water management is a key design and operating fact. Particulate and gas emission criteria influenced design as did occupational hygiene factors (dust, radon, housekeeping, maintenance access). Equipment selection and engineering standards were conservative and resulted in the plant attaining design performance in less than three months from the date of commissioning. A number of mechanical and operational problems were experienced and are discussed in the paper, however none of these problems have had a significant effect on production.

Jan 1, 1984

The Oregon-Idaho graben evolved after widespread Uwleiitic flood basalt volcanism associated with the arrival of the plume head of the Yellowstone hotspot beneath southeastern Oregon approximately 17-16 Ma. The north- to north- northeast-trending, 50 km-wide graben evolved between 15.5 and 10.5 Ma during east-west extension. The graben is part of a middle Miocene back-arc rift (1,100 km long) that includes the northern Nevada rift, the Baker and LaGrande grabens, and the Chief Joseph dike swarm of the Columbia River Basalt Group. The graben ceased to be a volcano- tectonic depression as the cross-cutting western Snake River plain began to evolve at approximately 10.5 Ma.

Jan 1, 1995

By Heath E, van Calsteren P, Turner S, McDermott F

U-Th isotope studies of recent volcanic rocks may be used to evaluate the depths and rates of melt generation beneath mid- ocean ridges and ocean islands. Island arc rocks exhibit a similar range in Th isotopes to that seen in both MORB and OIB, but while those with high (230Th/232Th) tend to have excess 238U, many of those with low (230Th/232Th) are in isotope equilibrium. The excess 238U is attributed to the preferential mobilisation of U in hydrous fluids from the subducted slab within the last 100,000 years, whereas the low Th isotope ratios in the higher-K arcs are primarily due to the introduction of subducted sediment. Preliminary results from mineral separates from lavas on Soufriere on the island of St. Vincent indicate that some of the minerals crystallised up to 50,000 years prior to eruption.

Jan 1, 1995

By Mitchell G. W, Purvis A. H

The Lady Loretta silver-lead-zinc deposit lies north of Mount Isa in folded and faulted Proterozoic carbonate sediments. The deposit was discovered in the late 1960's as a result of a soil geochemical survey. Subsequent surface drilling outlined mineralisation folded into a synclinal structure extending to a depth of 460 m and containing exceptionally high grades within the keel of the syncline. Pancontinental Mining Limited and Outokumpu Oy of Finland acquired the property in 1985.

Jan 1, 1988

By Oda Y, Hashiuchi M

In the smelting section, flexible fuels such as coal or coke are used in place of heavy fuel oil in order to utilize energy sources more efficiently. Heat recovered from the off gas of the furnace has been converted by the waste heat boiler into steam, which is used for self power generation and for heating or maintaining various temperatures. The amount of the recovered steam in the smelter is currently increasing due to maximum utilization of powdered cokes. The heat source required to maintain the temperature of the electrolyte in the tank house is electric power and steam. However until recent year this steam was provided by its own heavy oil combustion type boiler in the tank house since the amount of steam consumed in heating the electrolyte is large. Though experimental work over the last few years has shown the advantages of reducing steam in the tank house by fully covering the cell, the implementation of the full cover can lead to other operating problems. However various improvements, mainly the covering of the cell with a simple device, have led to greatly reduced steam consumption. As a result, steam for the tank house is now provided by the waste heat boiler only bringing more efficient energy usage.

Jan 1, 1987

By Prakash AJ, Singh PK, Dhar BB

Safety and stability of underground mine openings, coal pillars and water dams in the near vicinity of operating surface mines are endangered from excessive blast induced vibrations. This paper deals with the investigations carried out in four coal mines. Simultaneous measurements at equal distances from the source indicated higher level of vibration on the surface than those produced in the underground workings. The values of peak particle velocity (PPV) measured on coal pillars, body of water dam were lower than those measured on roof and junctions of the roadways. The parting of coal (3-4.5 m) between two sections vibrated with higher PPV compared to the roof of top section and floor of bottom section. In one case the influence of total charge fired in a round was significant in generation of vibration compared to the maximum charge/delay where monitoring was done vertically below the source.

Jan 1, 1995

The transgressive sedimentary sequence of the Notnnea Basin contains rhyolitic lavas and less voluminous mafic and intermediate volcanims of shoshonitic affinities which erupted simultaneously during the late Cretaceous. The shoshonitic volcanism shows a trend from early inafic to younger evolved intermediate lithologies. The rhyolites are consistently calc- alkaline. There is no evidence of 'mixing, of, the two magma types. The shoshonitic volcanism is the result of a short-lived subduction event related to sprcadime in the New Caledonia Basin and involved reactivation of an earlier Mesozoic subduction zone.

Jan 1, 1995

By Baird G. R, Jurak R. N

In this study Dynamic Finite Element Modelling is used to investigate the distribution of peak particle accelerations (PPA) induced in a rock mass by a vertical decked column of explosives. The rock mass is assumed to be viscoelastic. The influence of the delay time between decking charges, the viscosity attenuation (quality factor Q), the decking configuration, and the velocity of detonation (VOD) on PPAs is examined. The results of this paper are relevant to fragmentation since the nature of the fragmentation is related to the stress magnitude and hence the PPAs. It was found that increasing the VOD, and increasing Q increases the PPAs in the neighbourhood of the blasthole. However, the VOD and rock quality factor Q have little influence upon the distribution of PPA. It was also found that an even distribution of PPAs, at a fixed distance from the blasthole, could only be obtained by increasing the ratio of charge length to stemming length. The study showed that the amplitudes and distribution of PPA surrounding the blasthole was approximately independent of the delay time between the decked charges. The modelling also shows that the particle accelerations at locations below the bottom of the charge are relatively small and so the model predicts no substantial damage below the bottom of the charge after blasting.

Jan 1, 1995

By Corrans I. J

A wide variety of copper-bearing gold ores exist throughout the world which have yet to be processed economically for gold recovery. The copper minerals present in these ores can be many and varied and usually result in high cyanide consumptions and problematical levels of copper in leach solutions. The copper content is often assessed as being of nuisance value as the ores are generally of the grade or type which can support neither a copper project nor a straight gold project, due to the interference of copper. Many of these problematical gold-copper ores could possibly be processed economically for gold recovery using a novel ammoniacal cyanide leaching system which utilises a copper-ammonia-cyanide complex as an effective lixiviant for gold, yet limits copper dissolution and conserves cyanide. Results from recent testing have promoted a re-evaluation of the economics of treating some gold-copper ores. This paper describes the novel leaching process and discusses the conditions employed to treat a variety of gold-copper ores.

Jan 1, 1992

By Townsend IJ

The Upper Triassic Leigh Creek Coal Measures which include a number of seams of sub-bituminous black coal are preserved in four small intramontane basins. The largest is Telford Basin, 1,000 m in thickness. The coals, of variable thickness and quality, are mined by open cast mining methods and utilised for generation of electricity at Port Augusta. The combined proven and indicated reserves are about 100 million tonnes.

Jan 1, 1975

By Ypma PJM

The Westmoreland uranium deposits occur on the northern flank of the Murphy Tectonic Ridge in the upper member of the Westmoreland Conglom- erate. Uranium mineralization is spatially associated with the contact of the overlying basaltic Siegal Volcanics and the margins of in- trusive dolerite dykes which are geochemically similar to the Siegal Volcanics. Thermoluminescence (TL) measurements on 800 samples from within the orebodies and surr- ounding host rock (up to 8 kilometres away from the deposits) have indicated that all of the Westmoreland Conglomerate has suffered major radiation damagg attributable to at least 10 ppm uranium over 10 years. The underlying rhyolitic Mid Proterozoic Cliffdale Volcanics have distinctive TL glow curves indicative of radiation sensitization caused by high uranium contents. These vol- canics are part of the Mid Proterozoic volcanic event known to be enriched in uranium. The Westmoreland Conglomerate has been derived by erosion of the uranium-rich Cliffdale Volcanics and associated Nicholson Granite Complex which makes it likely that the Westmoreland Conglom- erate had a high inherent uranium content.

Jan 1, 1984

Five types of mineral resource were known in the sedimentary cover of the oceans and seas floors prior to the 1980's :1) hydrocarbon fields including some very large zones of oil and gas accumulation; 2) "Red Sea" type thermal oozes with increased concentrations of noble metals; 3) ferromanganese nodules; 4) concentrations of metallic sulphides ("Black Smokers"); and 5) cobalt-bearing ferromanganese crusts on the summits and slopes of seamounts. Since then, the so called "White Smokers", containing sulphides of copper and zinc, have been discovered. The ore horizons (manganese, copper, nickel and other metals) of the sedimentary cover of deep-sea basins comprise a sixth type of mineral resource in the oceans. These horizons have not only a theoretical, but also a principal economic significance

Jan 1, 1995

By Hagen G, Uhlig H

In the Federal Republic of Germany the thermal environment in underground coal mines has deteriorated progressively over the past years. The number and capacity of refrigeration plants have increased correspondingly. In recent years high capacity spray coolers have been used in addition to conventional cooling coils.

Jan 1, 1988

Comminution Kinetics equations are developed to take into account difference of grindability of mineral components. The equations describing both batch and closed circuit grinding or crushing processes are given. These equations are applied to industrial data to derive comminution kinetic and classification characteristics of the component minerals in a multi-mineral ore. Control strategy based on these concepts is presented.

Jan 1, 1985

By Robinson T

The paper describes a spreadsheet system that enables selection of projects and companies that meet the user's corporate exploration and/or acquisition philosophy. A regularly maintained commercially available database has been used as the basis for this system. It provides an easily accessible efficient com- prehensive search method. The technique enables ranking by various criteria, both technical and financial, to provide groups of projects/companies that are of interest. Initially, target size parameters such as reserves, production and mine life are applied together with geological criteria such as age and deposit type; the significance of the targets in the context of the Australian gold industry is addressed.

Jan 1, 1988

By McDonough RJ

Mechanical agitation is the preferred system for Carbon-in-Pulp processes. Agitator design requires an understanding of the relationships between energy, shear and flow and the nature of shear rates and shear stress distribution in an agitated tank. Laser techniques are useful when studying these phenomena. The alternatives are open impeller agitation or draft tube circulation. Each has advantages and disadvantages but both require careful choice of impeller and system geometry. Overall the draft tube circulator is the more attractive in many cases. Open impeller agitators are designed in accordance with established procedures for mineral slurries taking due account of shear effects in tanks containing carbon. Preferred tank proportions are 1:1. Circulator design methods were developed in the alumina industry before being applied to CIP processes. Optimum draft tube diameter is critical to power requirements. The overall system must be designed as an axial flow pump operating in a closed circuit. Such a system exhibits quite characteristic behaviour which requires an impeller of varying pitch angle and aerofoil section for best stability and efficiency.' Tank height may be 2 or more times diameter. Resuspension of settled solids can be assisted by a series of slots in the draft tube. These slots have the secondary effect of stabilizing hydraulic behaviour and reducing installed power requirements.

Jan 1, 1982