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By Carter D

The Chairman of this afternoon's session is Dick Carter. This afternoon is the culmination of this conference. We've looked in the first session at regulation; in the second session at valuation techniques and this session we look at valuation in practice. Dick's involvement in the mineral industry has been wide ranging and distinguished. Dick has worked with BHP since 1960, when he joined BHP Steel as a commercial trainee. Dick holds a B.Comm. from the Newcastle University College of the University of New South Wales and was educated at the Australian Administrative Staff College and Harvard Business School Advanced Management Programme. During the past decade, he has headed the minerals group's Aluminium Divison, Resource Planning and Development, Non-Ferrous Metals and Business Development Organisations. Dick currently serves as Executive Director of BHP Gold Mines Limited and Managing Director of Ok Tedi Mining Limited. His experience covers Australian Manganese Company, Mineral Deposits Limited, Northern Rivers Rutile, Tasmanian Electrometallurgical Company Limited, Mount Newman Joint Venture, Worsley Aluminium and Carnilya Hill Joint Venture Operating Committee. His industry associations include the Executive Board of the Gold Producers Association, the Federal Executive of the Australian Goldmining Industry Council as well as the World Gold Council. Ladies and gentlemen, Dick Carter.

Jan 1, 1989

In the humid, subtropical climatic conditions, typical of Papua New Guinean high-lands, auriferous carbonate-quartz lodes and stockwork veins of the Upper Ridges mine at Wau, have weathered in situ forming manganese dioxide-quartz wad flatmakes and veins. Vein assemblages and sulphidized host breccia have been chemically weathered to 20-25m depth, and microscopic grains of electrum (550-600 fine) formerly enclosed in carbonate, sulphide and quartz have dissolved in the oxidizing alkaline fluid. Coarse secondary electrum, crystalline and dendritic, is concentrated by manganese dioxide and at the base of chemical weathering. Fineness is unchanged, eliminating the possibility of gold and silver migration as a chloride complex. Experimental tests on the stability of thiosulphate, and its ability to dissolve gold and silver from colloid, crystal and synthetic alloy confirm that secondary electrum at Upper Ridges is most compatible with precipitation from (Au,Ag)(S203)23-; a complex readily destabilized in the presence of MnO., or with decreasing Eh.

Jan 1, 1984

The exploration methods used by the British Coal Corporation in 1990 improve the geological reliability of underground coal production. Although some of the techniques in common use have been proved to be effective, their limitations are recognised and concentration has been on the increasing integration of direct and remote sensing techniques. Attention is focussed onto first seam workings in sections of at least 2 metres in the depth range of 400-1200 metres and covers both surface and underground exploration. The case studies of exploration techniques and their effect on mine design at several existing collieries are representative of a wide range of geological environments within the more productive British coalfields. Notwithstanding such improvements in exploration and geological reliability, further new exploration technology is currently being investigated or trialled by British Coal.

Jan 1, 1991

By R Hall

The magmatic arcs of SE Asia and SW Pacific contain some of the worldÆs major magmatic-hydrothermal gold deposits. Most gold deposits in SE Asian and SW Pacific arcs formed during periods of plate reorganisation rather than during periods of normal or steady state subduction. These plate reorganisations were caused initially by the collisions of the Australian Craton with the Philippines-Halmahera Arc and the Ontong Java Plateau with the Melanesian Arc at ~25 Ma. A second Mid-Miocene period of mineralisation accompanied plate reorganisation following maximum rotation or extrusion of Indochina and cessation of spreading in the South China Sea at ~17 Ma. However, the vast majority of deposits from New Zealand to Taiwan formed since 7 Ma during an important period of tectonic reorganisation that accompanied and followed changes in the relative motion between the Indian-Australian and Pacific plates between ~8 and 3.5 Ma. Magmatism in unusual tectonic settings produced the most abundant and largest deposits with many deposits associated with high-K calc-alkaline, shoshonite, adakite and alkaline magmatism. In particular peak mineralisation appears related to melting of sub-arc lithosphere that has been previously modified by subduction. During large-scale plate reorganisation this can occur towards or at the end of a period of normal subduction, following arc collision or accompanying subduction reversal at approximately the same time in different parts of a complex system of arcs such as in SE Asia and the SW Pacific.

Jan 1, 2005

Capital expenditure on sampling and blending is often very difficult to justify. The costs are easy to estimate but the benefits likely to be obtained by constructing good sampling and blending facilities are generally difficult to estimate. For instance, improving blending of the ore feed to a smelter would improve throughput, yield and controllability ... but by how much? Similarly, better sampling would allow processing conditions to be dynamically adjusted and would improve extraction ... but by how much? Predicting benefits often requires the use of simulation models which carefully distinguish between true grades, predicted grades and observed grades. The parameters of these simulation models must often be estimated from rather inadequate information. These difficulties are illustrated using three scenarios.

Jan 1, 2005

By Clark T. M

Underground coal mining involves the disturbance of natural strata stresses formerly in equilibrium, the production of noxious and flammable gases and dust which can be both an explosion and a health hazard. It involves also the use of heavy, large equipment operating on natural floors and in confined spaces. Such operations are required to be carried out under artificial light. Much of the easier won coal, that is the shallower coal, from this State has already been extracted and in future workings will be required to go deeper. As the depth increases strata pressures will increase, gas production is likely to be greater and the production of dust will also increase. A further problem which has not yet reached significant proportions in Australia is the potential rise in working temperature. This will be occasioned not only by the use of large items of equipment which themselves generate heat, but due also to thermal gradients as the depths increase. The need for better employee training is now being widely recognised throughout the industry. Under present highly mechanised conditions new employees should not be required to work with or near heavy mobile machinery without proper training

Jan 1, 1976

Presidential Address Today I want to couple that prediction with a discussion on competitiveness and changing employment roles in our industry. A crude analysis of the intensity of use of metals in developed and undeveloped nations was undertaken by dividing the weight of copper, zinc, lead and aluminium used in countries by the population. In the developed countries which were basically the Western European States, USA, Canada, Australia and Japan, approximately 38 kilograms are used per annum. In the developing countries which were basically the South-East Asian country Korea, India, Pakistan and Taiwan, the usage is 5.3 kilograms. Thus, if the developing world is to catch up with the developed world, the intensity of use of metals will have to increase seven times. The usage of metals in the developed world is increasing at the rate of 1.5 per cent per annum while the rate of increase in the developing world is about 5.8 per cent. In this analysis, the population of the developed world was 850 million and the developing world 1.5 billion. Note that this analysis did not include Russia, China and most of the countries of South America and South Africa. I am sure that with time, these undeveloped countries will move into the developing category. In the long-term there is obviously great opportunity for us both in the primary and secondary processing required to meet world demand. Turning now to competitiveness and changing employment roles. I am sure that everyone here present is aware of the urgent need for Australia to improve its competitiveness. I want to try and relate unionism and industrial relations, management and tertiary education to our competitiveness. I wish to talk on these items as I see them in the past, the present and the future. So firstly unionism and industrial relations. It has been unfortunate for Australia that unionism was based on the United Kingdom craft system. It is not surprising that it was because UK has been the basis for almost ' all of our institutions and that has generally been of very great value to us. The craft system in our trade unions has lead to the demarcation problems of which we have all been well aware. This has been extremely limiting to the individual; it has limited his or her ability to broaden their scope of knowledge and far worse it has limited their ability to maximise their satisfaction at work as they have only been able to undertake part of a job, rather than being able to undertake a role in totality.

Jan 1, 1992

Ranger Uranium Mines Pty. Ltd. operates an open pit mine and ore treatment plant in the Northern Territory designed to produce 3 000 tonne/yr of U308 in yellowcake from 3 500 tonne/day of mill feed. The construction of this project was completed in 1981, 12 years after the discovery of the orebody. Wright-Davy, a Joint Venture of Wright Engineers and Davy McKee Pacific, were the Project Managers and Designers of the $270 million ore treatment plant and associated infrastructure. The project was designed in Sydney in -an office integrated with the Client, staffed by 35 key personnel drawn from Wright Engineers and Davy McKee, supplemented by personnel hired for the project. The peak Wright-Davy workforce in Sydney of 200 contained 113 design staff. The design principle of using the best practicable proven technology resulted in a plant which easily produces its design output using ore types outside the design criteria. The structuring of the project systems and industrial relations policies contributed to construction being completed within time and under budget. The plant was built without any major industrial dispute occurring and no dispute arose due to the uranium issue.

Jan 1, 1983

By Weller KR

Completely dry or completely wet materials are comparatively easy to screen, but materials with moisture contents between these two extremes can present varying degrees of difficulty. The presence of moisture can impair the performance of a dry screening plant in a number of ways: ò agglomeration of fine undersize particles onto larger oversize particles, resulting in the fine particles being misplaced to the oversize; ò increasing attractive forces between particles that hinder stratification and particle presentation to the screen; and ò blinding of the screen apertures caused by fine moist particles clinging to the screen which reduces the effective aperture size and the open area of the screen. Test work on full-scale screens has shown that the agglomeration of fine particles onto larger particles only occurs once the equilibrium moisture content of the ore is exceeded, and that the quantity of adhering fines present is proportional to the surface area of the larger particles. An -adhering fines screen model has been developed from this work, and by using relationships derived between the model parameters and feed moisture content, the effect of changes in feed moisture on both product quality and operation of iron ore dry screening plants is predicted.

Jan 1, 1993

By J Sarvinis

The design and operational aspects of fluidised solids transfer-cooling devices will be discussed in this presentation. The devices include air slides and fluoseals (also called seal pots, loop seals, etc), which are widely used in metallurgical plants and other processing plants. Cooling can be achieved while solids are transported in the solids transfer devices. The units combining solids transfer and cooling provide compact and clean plant layouts and also reduce capital and operational costs. Fluidised devices provide excellent gas-to-solids and gas/solids-to-surface heat transfer rates, hence high cooling efficiency. Fluidising gas, such as air, nitrogen or other gases, can be used as direct cooling mediums. Coolants such as water, steam and other liquid or gas cooling fluids can be used as indirect cooling mediums via tube coils immersed in the fluidised solids. The fluidised transport devices share some common features with fluidised bed equipment. The air slide is similar to a linear fluidised bed while the fluoseal is similar to a circular fluidised bed. Therefore fluidised bed design techniques are applicable to the design of the air slides and fluoseals. The heat and mass balance and temperature profiles of the devices concerned will be discussed in the presentation. The design criteria and operational philosophies of the critical components such as tuyeres and air spargers will also be discussed.

Jan 1, 2006

By J E. Everett, M L. James

When iron ore is crushed and split into lump and fines components, there are systematic differences between the lump and fines grades. Generally the lump product is richer in iron and lower in the other minerals, compared to the fines product. The grade differences between lump and fines, together with the lump percentage, are referred to as the ælump algorithmÆ. Mine estimates of grade, based on exploration or blasthole drilling, relate to head grade. The ælump algorithmÆ predicts lump and fines product grades from the head grade. This knowledge is important when developing mine plans. Different ore types can be expected to have systematically different lump algorithms. Previously, lump algorithms for specific ore types have been estimated by running the crusher with a single ore type over a sample period. This method is costly, interferes with production, and yields results of limited statistical power. It has been found that weighted-least-squares (WLS) multiple regression can be used to ascribe lump algorithms to different ore types, provided sample periods have sufficiently varied ore type mixes. This study discusses the method and its application to the analysis of Mining Area C crusher production records to estimate the separate lump algorithms, which could be applied to the different ore types. The analysis has enabled the set up of lump algorithms in the production system, to improve the grade control of lump and fines product. Some other relevant applications of the WLS multiple regression approach are also considered.

Jan 1, 2005

By T

THE Sulphide Corporation's works for the smelting of ores containing lead, gold, and silver are situated close to the Cockle Creek railway station, on the main Northern railway line, and are about 95 miles from Sydney and 10 miles from Newcastle. A branch line runs to the works, and siding accommodation and bins are provided for expeditiously handling all ores sent for treatment. The Corporation also possesses wharfage facilities at the port of Newcastle, where consignments of ores arriving by sea can be handled direct into railway trucks for conveyance to the works.The greater portion of the ore treated at Cockle Creek comes from the Corporation's mine at Broken Hill, but a large quantity of other grades is also purchased and treated.

Jan 1, 1918

In six deep hard coal mines situated in the coal district of the Saar and Lorraine, Saarbergwerke AG produce annually 9 to 10 million tons of coal. The coal is either coked or fired in power plants. Comprehensive planning work is done for the producing coal faces, 15 stone drifts and 60 seam headings. The computer can assist in drawing up the short- and medium-term planning by taking over, on the one hand, work done so far by hand and by supplying, on the other, additional information. The computer can draw up time schedules, can do quantitative calculations, can draw up plans for the em- ployment of manpower, machines and other equipment, and can calculate cost and earnings. It is ensured that all part plans are always adjusted to each other. Because of the volume of work involved, planning in this form and extent becomes possible only by the computer. Especially with the periodical continuation of planning, the new system facilitates the work to be done. The ideas of the planning engineer are and remain the basis of all planning work and the computer gives him an aid to assist him with calculations, report writing and feasibility studies.

Jan 1, 1977

Silica-Kaolin Sand Wet Sizing The Bulgarian deposits of silica-kaolin sand are localised in the eastern part of the Danube plain. After wet separation the raw material yields two products - washed kaolin (different grades) and silica sand (different grades). The water washing technology includes: disintegration; spiral classification; hydrocyclone classification and dewatering of kaolin grades; hydroclassification; sizing using drum screens and dewatering of silica sand grades. Research and development program has started to improve the silica-kaolin sand separation in processing plants. Based on the raw material and tails characterisation data and the preliminary experiments using Derrick Stacksizer screening machines a silica-kaolin sand wet sizing technology was developed. The full-scale pilot flowsheet includes the following units: Derrick Stacksizer equipped with 0.43 mm opening Derrick Urethane Panel; 500 mm Flat bottom Hydrocyclone; Derrick Stacksizer equipped with 0.150 mm opening Derrick Urethane Panel; 100 mm Hydrocyclone and Derrick Dual Motor Linear Motion Machine equipped with 0.064 mm opening Derrick Pyramid Panel. The pilot-test data clearly demonstrate that the new silica-kaolin sand wet sizing technology is suitable for Bulgarian silica-kaolin raw material. There are possibilities to increase the silica sand recovery increasing the production of silica sand grade PK 0.16 and starting the production a new grade PK 0.10.

Sep 13, 2010

By Lawson F

Arsenic-containing waste was dissolved into molten slags and the leaching behaviour of the quenched arsenic-doped slags (containing up to 2.3 wt per cent arsenic) was ascertained to evaluate the potential of this method as a means for arsenic disposal. The leaching behaviour was evaluated using acetic and sulphuric/nitric acid based solutions.From short-term (18 hour) leach tests, the amounts of arsenic in the leach solutions were found generally to decrease with an increase in the Fe(III)/Fe(total) ratio of the slag or an increase in pH of the leach solution. The amount of arsenic in solution increased with an increase in the slag basicity, the slag arsenic concentration or the surface area of the slag exposed to the leach solution. From longer term leach tests (up to 40 weeks) in the pH range 5 to 8, the arsenic remaining in the leach solution was believed to be controlled by sorption processes. The sorbent was an iron oxide-rich material which had the capacity to lower the arsenic concentration in the leach bottles to well below 1 ppm in some cases. At a leach solution pH over 9, the arsenic concentration in the solution increased with time, although the rate of solubilisation was much slower due to the high pH.Slags have the potential to stabilise arsenic and prevent it entering the environment provided attention is paid to the slag chemical composition and oxygen potential.

Jan 1, 1996

For the last decade Australia has been the leading exporter of both steam and coking coal. In the ten-year period 1989 - 1998 steam coal exports increased by 93 per cent and metallurgical coal exports increased by 50 per cent. However, profitability of the steam coal sector has been disappointing. The coking coal sector, especially the hard coking coal segment, has fared better but its profitability was more because of its ability to maintain relatively high prices rather than its inherent productivity. Until quite recently the Australian coking coal sector was widely expected to be able to maintain this comfortable state without undue effort for the three major æpartnersÆ; the companies, the State Government and the unions. But coking coal could now be heading down the path followed by steam coal that ends with long-term over-supply and, despite steady improvements in productivity, poor profitability. Steam coal entered the ænewÆ era of long-term over-supply some years ago. Over-supply was due to the rapid increase in production in Indonesia, often from new mines and Australia. AustraliaÆs production rise was underlain by the apparent belief that the best way to lower costs was to increase production. In the first couple of years costs didnÆt fall much but the additional tonnage was sold at lower and lower prices into the spot market. By mid-1998 the difference between the contract price set with Japanese utilities and spot sales was often in excess of $US12 per tonne. Japanese contract prices and tonnages have since fallen significantly. Steam coal has moved from being a product to being a commodity. Any profits are due more to the low Australian dollar rather than inherent mine productivity. Seaborne coking coal trade has been dominated by Australia, Canada and the USA, with the USA becoming less competitive. Unfortunately, when the Queensland capacity expansion was well down the pipeline, the Asian financial crisis occurred and the Japanese economy entered what appears to be a long-term recession. Contract prices fell 18 per cent, tonnages decreased and some mines have been reclassified as supplying lower priced coking coal. The paper analyses past and expected future trends in labour and mine productivity, rail freight and FOB export port cash and total costs of the Australian steam coal and coking coal sectors and discusses the market outlook for Australia. The future economic viability of the industry is analysed and discussed in the light of the rapidly changing global environment.

Jan 1, 2000

A new classification of subduction related (epithermal- / mesother-mal) gold mineralisation styles based on the tectonic framework they occur in, has been found helpful in practice. It offers a ratio-nalisation of exploration efforts during all stages of work.Methodology on the ground during first pass- and follow up explo-ration which has been found effective for the various mineralisa-tion styles is being briefly outlined.

Jan 1, 1990

Mining engineering, metallurgy and minerals-related geology have proud traditions and are essential professions to support a safe and sustainable minerals industry. However, the future of these professions is under threat. The courses that produce such graduates are disappearing worldwide and the number of graduates available to enter the industry has been falling in English speaking countries for at least a decade. It is unlikely that this problem will be remedied by æsupply and demandÆ. Instead, some active intervention is required.

Jan 1, 2004

In 1952 when universities imposed fees on students and most students won either Commonwealth or Government department or private scholarships to study, I won a scholarship to study mining engineering at the University of Technology in Sydney. The univ

Jan 1, 1994

Agitation leaching data has generally not been analysed to extract the maximum amount of information that is available. Analysis of heap leaching systems has been developing over the last five years to include the underlying rate determining process. This has been found to be diffusion control for all copper leaching; irrespective of whether they are oxide or sulfide minerals. Extension of the diffusion model has enabled better scale-up protocols to be developed. Acid consumption in copper heap leaching operations has been found to be a first-order chemical controlled system. The analysis of the data is relatively straightforward. However the interpretation and scale-up is not as direct as for agitation leaching. The differences in the residence time distributions (RTDs) are required to properly account for the scale-up between test columns and field. The leaching of oxide copper in agitated systems has also been found to be diffusion controlled. However, there are significant differences in the control mechanisms. Initially the leaching control is the supply of acid to the mineral surface. This is limited by the diffusion through the surface boundary layer and is thus subject to the level of agitation. Higher agitation provides thinner boundary layers and faster diffusion rates. Similarly, higher grade material creates a thicker concentration boundary layer and relatively slower leaching. Acid consumption in agitated leach systems is also a first-order system. However, the interpretation of the RTD is easier from batch testing to continuous multiple CSTR series plant operations. Altering the method of acid delivery can significantly reduce acid consumption rates. Predilution of the acid minimises the local acid concentration near the addition point and can reduce the consumption by up to 50 per cent. Modelling of the combined leach rate(s) and acid consumption rates in agitated systems allows comparison of various leaching strategies and selection of the most appropriate. Similarly, the model allows the identification of economic limits to leach recovery; where the cost of acid consumption is greater than the value of the copper recovered. From this analysis selection of residence times for agitation leaching can be determined. The modelling tools are useful in identifying optimum conditions for the leaching process.

Jan 1, 2005