Search Documents

By D R Quick

The Goodall gold mine is located 30 km east of Adelaide River, within the Pine Creek 1:250 000 map sheet, at 8 525 000 mN: 750 000 mE, on the AMG grid. The first gold was poured in April 1988 and the mine closed in September 1993, having produced 228 400 ounces of gold from 4.095 million tons of ore, at a head grade of 1.99 g/t. Oxide and primary ore was mined from one large open cut and low grade oxide ore from three smaller pits. The gold mineralisation was discovered in 1981 by means of a helicopter borne rock chip sampling survey, which delineated 13 discrete anomalies. Systematic grid sampling of rock chips outlined an area of 1300 m by 300 m within the 2.0 g/t contour. Over 7500 m of costeaning was used to delineate the A and B-Pod mineralised areas. Geochemical soil sampling played only a minor role in the discovery and geophysics none at all. By the end of 1984, 40 diamond drill holes had been completed and a resource of 3.63 million tonnes at 3.0 g/t calculated. In January 1985, Western Mining Corporation Ltd became a joint venture partner and funded exploration to cam a 60 per cent interest. Additional drilling led to a feasibility study in 1987, based on a Measured and Indicated resource of 4.25 million tonnes at a grade of 2.35 g/t. The host rocks are quartzo-feldspathic wacke and interbedded phyllitic siltstone, of the Proterozoic Burrell Creek formation. The main zone of gold mineralisation, A-Pod, occurs in a sub-vertical vein array, up to 50 m wide and 800 m in length, of quartz and sulphide veins (5-20 mm wide), It is parallel to and on the east limb of an upright, north plunging anticline. Five types of veining have been recognised, with the bulk of the gold mineralisation associated with quartz-pyrite-arsenopyrite and chlorite-quartz-pyrite veins. The gold occurs as particles, from 1-20 micron, as inclusions and along fractures in pyrite and arsenopyrite and to a limited extent in chlorite. The mineralisation is epigenetic and structurally controlled by fractures developed during an earlier folding event. The gold is assumed to have been derived from the underlying sediments of the Koolpin Formation by hydrothermal fluids emanating from the deep seated northern margin of the Cullen Batholith. Precipitation of gold may have been controlled by variations in temperature and pressure.

Jan 1, 1994

By M Gerards, M Steinberg, T Graham

The quality and quantity of Australia’s secondary deposits, which include tailings streams and tailings dams, are higher than most countries’ primary deposits. In addition, these secondary deposits have already been mined and processed, meaning that the recovery of high-grade product requires low capital and operating costs.The most widely used process for the recovery of these valuable fine and ultra-fine hematite iron particles is the wet high-intensity magnetic separation technique, originally developed by Dr Jones over 55 years ago. Many of the original machines are still working today.The aim of this paper is to demonstrate the capabilities in terms of grade and yield of using sophisticated magnetic separation modules. All results and figures are obtained from test work and design and engineering work with material from the Pilbara. In addition, consideration is given to dewatering of iron ore product and tailings.Two types of tailings have been identified for processing. Firstly, tailings that have already been deposited in a tailings storage facility, and secondly, live tailings streams from an existing wet iron ore beneficiation plant. In both cases, the technical and practical results are shown along with relevant flow sheets and plant layouts. Finally, this paper highlights the total predicted power and water consumption, capital requirements and projected operating expenses.The results show that the operating costs are significantly lower than the mining and processing operations that are required for an equivalent amount of iron ore. The recovery of iron depends on various factors but is within the 30–50 per cent range at an equivalent grade to the mainstream product. Another significant benefit is that the magnetic separation process is water positive, meaning that water is released rather than added in the process.The processing of the Pilbara’s secondary deposits will therefore result in an overall reduction in operating costs, an increase in product yield from a plant, extend the life-of-mine and offer environmental benefits by reducing the tailings footprint and water usage.The quality and quantity of Australia’s secondary iron ore deposits and tailings are such that many other countries would judge these as equivalent to primary deposits. Furthermore, these tailings are already mined, available and liberated to such an extent that the recovery of a valuable product is highly economical in terms of capital expenses and operating expenses.CITATION:Steinberg, M, Graham, T and Gerards, M, 2015. Recovery of iron ore fines and ultrafines from tailings by using wet high-intensity magnetic separation – JONES WHIMS, in Proceedings Iron Ore 2015, pp 191–196 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By Stanley I. M, Brett D, Dickson R

The Mt Lyell Mine, situated in Queenstown on the west coast of Tasmania, has a production history of more than 100 years. Previous mining activities have resulted in substantial modifications to environmental conditions at Mt Lyell and disposal of sulphidic waste rock across the lease has left a legacy of on-going environmental impacts including acid drainage (AD). In 1995 Copper Mines of Tasmania (CMT) was granted a mining lease Irons the Tasmanian State Government for redevelopment of Mt Lyell and indemnity from actions concerning pollution from previous occupation and use of leased land. The Environmental Management Plan (EMP) for the Mt Lyell redevelopment committed CMT to be responsible for waste rock dumps generated from their activities and to ensure that management is in-line with best practice environmental management principles. CMT commenced commercial production in December 1995 with sulphidic material from development of the underground Prince Lyell mine reporting to a single waste rock dump constructed according to a management plan developed in July 1995 and superseded by a management plan for extension in May 1997. The CMT waste rock dump currently has a total capacity of 220 000 m- and approximately 120 000 m3 of rock have been placed to-date. Material reporting to the dump is placed in a densely compacted state to a controlled surface profile. The dump is clay capped and a final revegetated soil layer placed on top. A rock pitched drain extends down to a wetland area in order to remove stormwater and minimise possible soil erosion on the revegetated sections. An integral part of the management plan for the waste rock dump involves characterisation of waste rock to identify geochemical rock types according to acid forming potential with provision for selective placement within the dump. High-risk materials are selectively placed and covered within the core of the waste rock dump, where possible, to control sulphide oxidation. Monitoring equipment has been installed in the waste rock dump by the Australian Nuclear Science and Technology Organisation (ANSTO) and an on-going monitoring program has been established to demonstrate the integrity of the dump cover as a barrier to the influx of atmospheric oxygen into the dump. The overall objectives of this program of work are to control the oxidation of sulphidic waste rock in the waste rock dump, minimise the risk of AD, prevent pollution of the aquatic environment and thereby demonstrate the integrity of the CMT waste rock dump management Strategy.

Jan 1, 1997

The invitation to speak today was in the form of a single sentence instruction: How does your company run and how do you communicate from top to bottom? It looks like I'll have to let you into our little secret. The team at Croesus know what works for us but we've never talked about it with others - least of all presented it at a conference such as this. In fact we tend to avoid the jargon normally associated with Best Practice or TQM, however in our own way, each of our staff are 100 per cent loyal to our company's aim to maintain and strengthen our commercial success. Just how we achieve this at Croesus is the subject of this presentation today, but first a little history. My dear old grandfather arrived in Kalgoorlie, as a mining engineer 100 years ago. Do you think he would have chuckled if someone suggested to him that a hundred years later we would just be starting to understand Kalgoorlie's geological mysteries? Well, here we are 100 years later and Croesus Mining is fortunate to be part of a generation now realising the true potential of Kalgoorlie's Goldfields. This provides us with a very fertile field in which to sow the seeds we can obtain from the World's Best Practice in Mining and Processing. With each new mineral deposit being discovered, old theories are being exploded. Each new deposit has a personality of its own, leading to some belated pioneering theories of where to drill next, and how to reduce internal costs so that we can win the war against constantly increasing external costs. What we have now and what the old timers didn't have is a huge database of geological input spanning several gold booms and a couple of nickel booms. My only interest in history is to pick up the points that may help us for our future. This is what we are doing in our company which is something of a David, in the David to Goliath range of mining companies in Australia. As a humbling thought; of the 115 164 tonnes of gold that the world's mines have produced throughout history, four tonnes have been produced by Croesus Mining. That's equivalent to 0.003 per cent of the total world's gold production. In the past financial year we achieved a dividend yield of five per cent. To put this into perspective, that's over twice the dividend yield of BHP, Australia's largest company. As we are somewhat less known than BHP, let me spend a few moments giving some particulars of our company's background.

Jan 1, 1995

The ore milled from the Lead Lode of The Zinc Corporation leases consists of a fairly granular mixture of galena, marmatite, chalcopyrite, tetrahedrite, pyrrhotite, pyrite, and lollingite with a gangue association of calcite, quartz, bustamite, rhodonite, mangan-hedenbergite, garnet, fluorite, mangal1o-calcite and apatite. The silver content of the ore occurs in three minerals-tetrahedrite, dyscrasite, and pyrargyrite, the last two mentioned occurring in microscopic association only. Other metallic and gangue minerals are also present in this complex mineralogical association, but do not influence the milling operations. Fortunately, the silver minerals favour the galena and chalcopyrite as their host minerals, thus facilitating the recovery of both copper and silver in the lead concentrate. The ore from the Lead Lode assays from 14-18% lead; 3·0-4·5 oz. silver per ton, and 9·5-12·0% zinc.A parallel lode, known as the Zinc Lode, is well developed in The Zinc Corporation leases. This lode assays from 6-8% lead, 1·5 oz. silver per ton, 18-25% zinc with a siliceous gangue. The common Lead Lode gangue minerals-ealcite, rhodonite, bustamite-are very rare in present underground exposures. No metallurgical work was done on this ore during the pilot plant operations.The aim in the milling process is to produce: 1. A lead concentrate with the maximum economic recovery of lead, silver, gold, copper and antimony, and minimum zinc content.2. A zinc conc,entrate with the maximum economic recovery of zinc, cadmium, and cobalt, and minimum iron, arsenic and fluorine content.3. A waste residue containing sufficient granular material to be utilized as underground fill.In considering the economics of the milling practice the above three requirements plus consideration of the tariffs submitted by the purchasers of concentrates were the deciding factors in the evolution of the present milling practice.Towards the end of 1924 The Zinc Corporation Limited added to and adapted the old zinc tailings plant for the treatment of 5,000 tons of crude ore per week. This plant, which operated until January, 1936, was in general principles similar to the standard Broken Hill methods of ore concentration, whereby the galena was recovered by the gravity concentration methods of Hgging and tabling with selective flotation concentration of the residual galena and marmatite. One important difference from other Broken Hill plants was that the primary grinding of the jig tailing was performed with flint-loaded mills operating in closed circuit with revolving screens. Two primary grinding sections were installed, each...

Jan 1, 1941

By J Y. C Lo

The construction of two drainage tunnels and the associated subvertical drain system at the Po Shan area in Hong Kong was completed in December 2009. This project is the first of its kind to utilise drainage tunnels and a network of subvertical drains to regulate the groundwater table to enhance the long-term stability of the hillside of Po Shan area.The groundwater levels, monitored by preinstalled piezometers, once exhibited dramatic drops during drilling of the subvertical drains; however, have recovered from natural replenishment after effectively plugging of the drains. The level of groundwater drawdown is in line with the design function of the subvertical drains. In order to understand the groundwater flow pattern in the Po Shan area during and after construction and to set out operation schemes for the subvertical drain system so as to control the groundwater table in the Po Shan area, a post-construction review has been carried out to examine the behaviour of the drainage system and its impact on the surrounding subsurface groundwater flow.This paper presents a review of the groundwater monitoring data during and after the construction of the drainage tunnel system covering a period of over 3.5 years. A simplified conceptual hydrological model is developed, which has been verified by the monitoring data, to capture the key elements with regard to groundwater variations in different stages of the construction. The performance of the tunnel and subvertical drain system as revealed from these field measurements is discussed.

Mar 8, 2011

By J Rostami, T Afshar, M Sharifzadeh

Accurate estimation of rock load and selection of types of ground reinforcement to match post-failure behaviour of rock mass are important issues to assure tunnel stability. This paper focuses on the main factors affecting rock load to evaluate the capabilities of the existing models for prediction of rock load. Rock mass properties, project features and excavation method, as well as ground conditions and stress condition were found to be the key factors affecting the magnitude of rock load. Field data from tunnels of about 37.5?km driven in several geological structures in non-squeezing ground was used in this study. An in depth statistical analysis was performed on data to find correlations between the input parameters and measured/observed rock load. A weighting system was proposed to obtain the proper contribution of each factor for estimation of rock load in tunnelling through various ground conditions. The new classification system offered predicted values for rock load that were in a good agreement with the actual field measurements. The high disturbance factor (D>0.4) was the prime factor which controlled the rock load. Rock mass quality was the second key factor influencing rock load, which could be estimated by GSI, GSIresidual , especially when combined with tunnel depth.CITATION:Afshar, T, Sharifzadeh, M and Rostami, J, 2014. Estimation of rock load for tunnels with different disturbance factors, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 3–8 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By K Ehrig, V Liebezeit, E Macmillan

The results from metallurgical test programs are used in feasibility studies for design of new plants and brownfield expansions, in long term mine plans, and to make decisions in an operating plant. There are many elements which contribute to a well-constructed test work program. Ultimately, understanding the accuracy and precision of the test work results is critical to ensuring good decision-making at various phases of a project.Every resource drilling and associated assaying program will have a quality assurance / quality control (QA/QC) component, however this often seems to be overlooked in metallurgical testing programs. The principles of “international standard” or “certified reference material” samples and replicate/duplicate testing can be applied to metallurgical programs, although there are metallurgical-specific considerations in both generating and analysing the data.This paper will describe the QA/QC program carried out within the Olympic Dam geometallurgy program. It will present results in the form of case studies from ten years of testing of replicates and bulk reference samples for industry-standard comminution tests as well as laboratory flotation and leaching tests. The Olympic Dam geometallurgy quality control program has enabled quantification of the precision of metallurgical testing and improved our understanding of the best possible modelling results given the underlying dataCITATION:Ehrig, K, Liebezeit, V and Macmillan, E, 2017. Metallurgical QA/QC – who needs it? The Olympic Dam experience, in Proceedings MetPlant 2017, pp 31–44 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

By G D. McDonald

Flinders Mines is an ASX300 iron ore explorer and developer with a tenement package located in the Hamersley Ranges region of Western Australia, approximately 70 km north of Tom Price. Exploration over the past three years has identified a Global Resource in excess of 740 Mt at a grade of 55.4 per cent Fe (+50 per cent Fe cut-off). This resource is spread across multiple deposits and has been divided into a number of mineralisation type domains based on geometallurgical and geochemical boundaries. These domains are comprised of transported haematite rich detrital iron deposits (DID) and goethite dominant Channel iron deposits (CID) as well as in situ bedded Brockman iron deposits (BID). On the basis of differences in physical and chemical characteristics, the DID have been divided into four discrete units. The four DID units form a stratigraphic sequence with the iron grade increasing and the contaminant concentrations decreasing with depth. The upper DID unit is lower grade and currently unlikely to provide a marketable product, without signifi cant beneficiation. The lower three DID units, together with the CID and BID, are of a higher quality and have the potential to yield marketable ore. The ability to define and recognise these different units has resulted in a more reliable and robust geological interpretation and hence greater confidence in the resulting resource model. This has been evident in the excellent conversion of inferred to indicated resources.

Jul 11, 2011

By B Armstrong

The Proterozoic poly-metallic Trilogy deposit was discovered in 1997, and until recently, mining evaluation was stalled due to poor metallurgical performance. Unlocking the substantial economic value of the deposit required a coming together of geologists, mineralogists, metallurgists and mining engineers, who by working collaboratively, uncovered the detail necessary to allow the required metallurgical breakthroughs to occur. The deposit itself is described as a sedimentary exhalative (SEDEX), with an enriched lead-zinc-silver core surrounded by a broader envelope of copper-gold mineralisation. The geological domains were defined in broad terms based on the style of mineralisation, assay values and lithology. These domains, while adequate for the resource estimation process, failed to translate into representative metallurgical domains. Additional work with new techniques defined regions in the deposit with altered processing properties which could not be recognised by conventional geological logging. Such additional complexities could not be appreciated at the outset of the metallurgical test work program.These regions were defined by applying the EDTA analysis method for recognition of where the valuable sulfides, particularly galena, had been partially modified by oxidising conditions. Hence, the flotation response of the valuable sulfide minerals was diminished and the increased amount of heavy metal cations available in the system significantly reduced selectivity in the flotation process.Understanding the detail of this complexity was essential in determining representative metallurgical domains, which was the first step in the long road of development.

Sep 5, 2011

By Whiting AN

Major changes in the world in recent years are changing the criteria for selection of future developments. Oil prices soared during the 1970's while commodity prices including metals and minerals fell. Many new independent nations, have been created and now control the resources in areas which were once part of great colonial Empires.

Jan 1, 1983

From March to May of 1963, the Bureau of Mineral Resources carried out an experimental aeromagnetic survey at Cobar, New South Wales, to field test a proton-precession magnetometer installation in the Cessna aircraft VH-GEO. The Cobar area was chosen as considerable information was already held on the Earth's magnetic field there, which was known to provide a range of anomalous areas that are not excessively disturbed.A procedure for survey flying and methods for processing data were developed during the survey. Contour maps of the aeromagnetic results were produced in the field. The experimental survey was successful in outlining magnetic anomalies in detail.INTRODUCTIONSince 1951 the Bureau of Mineral Resources, Geology and Geophysics (B.M.R.) has carried out an airborne magnetometer exploration programme with DC.3 aircraft carrying fluxgate magnetometer equipment. Recently a proton-precession magnetometer was developed by the Design and Development Group of the B.M.R. for observatory use. One unit modified for airborne use was installed in the Cessna light aircraft, VH-GEO. The Cessna was modified structurally to take the magnetometer, associated bird, and winch gear.The proton-precession magnetometer has many good features.1. It utilises the transistor and associated solid-state devices in its electronics, and hence is light and small.This is the basic feature allowing its installation in a light aircraft. The transistor circuits have a high reliability factor and owing to the card sub-unit...

Jan 1, 1964

By J F. Seale

The design of the settling pond for the Malvern Hills opencast coal project was based on a primary requirement to control runoff and sediment generated from the immediate 6 ha mine catchment, which included two seepages from old underground workings. The pond has been particularly effective in controlling turbidity in the outflow water, with the consent limit of 50 NTU being met on all but one occasion and normal levels of discharge less than 10 NTU. Water quality testing carried out at the time of consenting indicated that there were no acid-generation issues with the proposed mine site in dominant mudstone strata of the Broken River Formation, and that water from the old mine workings was near-neutral in terms of pH and well-buffered. However, it became apparent over the very dry summer of 2003 - 2004 that slaking of the exposed mudrocks in the mine batters was resulting in significant acidity generation, and outflow pH levels were well below the consent limit of 6.5 during and following periods of rainfall. Although these acidity problems have been remediated in the short-term by the use of lime products, it is clear that a programme of lithotype characterisation for AMD should have been undertaken and this has now been implemented. Design of long-term acid drainage control measures is being carried out, and will probably be based around the use of hydrated lime for pH control with enhancement of natural wetlands.

Jan 1, 2004

By R P. Langford, T A. Moore

Indonesia over the last 15 years has experienced a surge in coal exploration, which has led to the development of a major export industry. This coal exploration has improved the understanding of the geology of the Indonesian coal deposits. The main economic coal deposits are of Eocene and Miocene to Pliocene age, which mainly occur in Kalimantan and Sumatra and were formed from peat deposits in an equatorial paleoclimate similar to that prevailing today. Some of these peats were domed peats, which grew above the normal water tables, under a climate of year-round rainfall; these peats grew above the level at which waterborne mineral matter can enter the system, resulting in low ash and sulphur, and locally very thick coal. It is believed that such peats have formed the unusually thick, low ash, and low sulphur Miocene coals of Indonesia. Coal deposits of Eocene age are typically characterised by thinner seams, with relatively higher contents of ash and sulphur. The Miocene coals and Eocene coals both appear to have formed in lacustrine, coastal plain or deltaic depositional environments, similar to the modern peat-forming environments of eastern Sumatra and parts of Kalimantan. The Eocene coals formed mainly in extensional tectonic settings. Miocene - Pliocene coal deposits formed in a range of tectonic settings; the most significant, for large economic coal deposits, are the foreland basin setting of the large Neogene coal deposits of South Sumatra.

Jan 1, 1999

Taking the third meridian as the eastern boundary of proved payable auriferous country, there is a stretch of country, nearly 600 miles in width, in which no appreciable amount of gold has yet been discovered. Many prospectors have attempted to .penetrate or traverse it, but comparatively few have thought it worth while proceeding with the examination.The desolate stretch of waterless desert-the very few and insignificant outcrops through the sand and the almost total absence of feed for horses have, combined, presented such a barrier as to preclude prospecting. The few who have traversed the country are eloquent in denunciation, yet their investigations, necessarily hurried, are not quite satisfactory. The absence of water utterly debars a thorough examination being made. Gold may exist in quantity, yet it would have to be extraordinarily plentiful to render its obtaining profitable. Too fantastic is the idea of its ever being a mining district; shifting sand to traverse, utter absence of wood and water render the notion absurd. Likely looking belts occur, but these in all "cases are small and remote from water. Gold has been obtained from likely look ing quartz reefs, but only by fire assay, and then but a few do to the ton. Without wishing to be pessimistic, I would unhesitatingly declare that east of the third meridian, and between the parallels 25 and 30 degrees in West Australia, there is no gold in payable quantities.

Jan 1, 1901

With the launch of Immersive Technologies' next generation of Advanced Equipment Simulators for the mining industry, correlating and influencing safety, productivity and maintenance with operator competency improvements is now made even more effective. In early 2008, Immersive assembled a project team to investigate the potential linkages between operator competency and performance. Advanced Equipment Simulator Users with a range of sophistication were interviewed and consulted. The result was new and enhanced 'value realisation' programs to directly assist mine sites to deliver the expected return on investment (ROI) from simulators and operator competency development. In just over one year, 29 mine sites around the world have benefited from 34 completed programs. Case studies have been compiled to demonstrate the impact of the implementation of this approach, including at the following operations: Anglo Coal - Callide (Australia), Freeport McMoRAN - Grasburg (Indonesia), Equinox Minerals - Lumwana (Zambia), Peabody Energy - Cabllo (USA), and Xstrata - Lomas Bayas (Chile). Significant performance improvements have been achieved including: reductions of 47 per cent in gear shifting and 37 per cent in over speed errors, improvements of 68 per cent in park break errors and 12 per cent in spotting time, and increase of 54 per cent in passing emergency fire handling competency tests. This presentation draws on these case studies to clearly demonstrate the linkage between improved operator competency through the implementation of training programs tailored around Advanced Equipment Simulators and production performace measured by a range of standard metrics at mines around the world.

May 1, 2010

The End of the Line for Roadway Development By Michael Kelly, CSIRO Exploration & Mining Michael Kelly highlighted that roadway development performance remains one of the threats to expansion of Australia underground coal exports to the growing Asian market. In a recent industry study, automation was highlighted as one of seven strategies for roadway development improvement. Growing Asian markets The expansion of the Asian coal market is a long term driver for expansion of the underground coal industry in Australia - if significant productivity improvements are made. Imports of steaming coal by Asian APEC members are predicted to rise by from 150 MT to 190 MT. Australia is one of the few countries which has a potential capacity larger than predicted internal needs. Predictions are for exports of black steaming coal from Australia to increase from 50.3 MT in 1992 to 106.3 MT in 2010. To meet this prediction, an investment of $10.7 billion (in 1992 dollars) will have to be made in mining and transport facilities. This is equivalent to the opening of a major new mine each year until 2010. Many of these mines will be underground operations. However, much of Australia's capacity to respond to increased Asian demand will depend on its ability to develop underground technologies and improve productivity. The inability to make sustained improvements in roadway development rates has to date been one of the main reasons why new underground projects have failed to deliver the expected returns.

Jan 1, 1997

THIS SYMPOSIUM ON AUSTRALIAN BEACH SANDS IS MOST TIMELY; WHEN WE ARE APPROACHING PEAK PRODUCTION FROM THESE RESOURCES AND WHEN PRICES ARE GOOD, BUT THE RESOURCES CAN BE SEEN TO BE COMING TO AN END IN THE LIFETIME OF OUR YOUNGER COLLEAGUES - 20 TO 25 YEARS AS WE HEARD FROM ROY TOWNER TODAY. THE SPREAD OF PAPERS HAS BEEN 15 PERCENT EACH ON GEOLOGY AND THE MINERAL RESOURCES, WITH 25 PERCENT ON LAND USE AND ENVIRONMENTAL PROBLEMS. I AM PLEASED TO SEE 20 PERCENT HAS BEEN ON TREATMENT PROCESSES AND 25 PERCENT HAS BEEN CONCERNED WITH DOWNSTREAM USES. I SUSPECT THESE RATIOS ARE DUE IN PART TO THE WAY PAPERS WERE CALLED FOR, BUT THEY ALSO SUMMARISE CLOSELY THE BALANCE OF INTERESTS IN THE INDUSTRY. NOTE AGAIN; 30% CONCERNED WITH SUSTAIN -ING RESOURCES, BUT 25% WATCHING LAND USE AND IMPOSING CONTROLS; 20 % IMPROVING THE PRESENT PROCESSING, AND A HEALTHY 25% WITH AN INTEREST" IN WHAT HAPPENS TO THE MINERAL CONCENTRATES. I SHALL RETURN TO THIS FOURTH POINT AT THE END OF MY REMARKS. THE POSSIBILITY OF ADDITIONAL HEAVY MINERAL SANDS IN NEW AREAS WAS HINTED AT BY M.S. SHEPHERD (EG TERTIARY SHORELINES OF THE MURRAY BASIN). OLD FOSSIL SHORELINES, WELL REMOVED FROM PRESENT SHORES ARE AN IMPORTANT MINERAL SOURCE IN CHINA AND IT WOULD HAVE BEEN INTERESTING TO HEAR FROM THE SEVERAL COMPANIES EXPLORING IN THE MURRAY BASIN. I ALSO NOTICED THAT WHILST OUR MONAZITE

Jan 1, 1986

By Plamer D. J, Newman O. M G

The Effluent Treatment System at Pasminco Metals - EZ (PMEZ) was commissioned in December, 1991 and has operated satisfactorily, ensuring that aqueous discharges from PMEZ comply with the Tasmanian Environment Protection Act. The system treats both spills and run-off from the Zinc Plant, and acidic liquor generated in the gas cleaning section of the Sulphuric Acid Plant. The spills and run-off from the Zinc Plant are collected in a large catchment pond. The pond liquor, after partial neutralisation with sodium hydroxide to pH 4, and removal of suspended solids, is preferentially recycled to the Zinc Plant, for example, for washing of residues. Liquor which cannot be recycled, is treated in the Lime Neutralisation Section. The other input to the Lime Neutralisation Section is the acidic liquor from the Sulphuric Acid Plant from which mercury has been removed by contact with aluminium pellets in a fluidised column. In the Lime Neutralisation Section, the liquors are blended and neutralised to pH 10 by the addition of slaked lime. The heavy metals and most of the fluorine are precipitated. The precipitated solids are removed in a thickener with part of the thickener underflow being filtered. Most of the thickener underflow is recycled to generate solids that settle rapidly and filter well. The filter cake is returned to the Zinc Plant for the recovery of contained heavy metals while the thickener overflow is discharged to the Derwent River.

Jan 1, 1993

At moderate depths this question is of relatively small importance, but at depths over 2,000 feet it becomes a matter of some consequence. The rate of increase of temperature with the depth varies in different localities, but as a rough average we may take it to be about 1° Fahr. for every 50 feet of depth. The variation of temperature of the earth's surface from summer to winter penetrates to a comparatively shallow depth. At 50 feet the variation becomes practically insensible, and the temperature of the strata will be about the mean temperature at the given locality, from 60° to 75° F. in this country or the comfort of men working in the mines it is desirable to maintain a temperature of about 70° F. in the workings, or approximately the temperature of the strata near the surface.In order to obtain some idea of the magnitude of the undertaking involved in cooling a mine, I have examined the effect of placing in a long drive an apparatus by means of which we can abstract heat at a uniform rate from the drive, keeping, thetemperature nearly the same at all points of the drive at any given time.The lowering of temperature 70 F. at any distance feet from the centre of the drive (treated as a cylinder of the same sectional area as the actual drive), after an interval of time days from the commencement of the operation is given by the formula...

Jan 1, 1907