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Recent well-publicised problems with the start-up of new mining projects have continued to feed the perception that the mining business in general and Ore Reserves in particular are a poor risk. New mines commonly experience difficulties when the true variability of ore characteristics becomes apparent during commissioning. At this critical stage, the impact of lower metal recovery, reduced throughput or increased consumption of reagents and energy can have a catastrophic effect on economic returns, as illustrated by the premature closure of some operations. There appear to be several common reasons contributing to the poor performance of mining projects, of which three are examined here: lack of early risk assessment before feasibility studies are started, inadequate sampling for metallurgical test work and variability of the run-of-mine (ROM) ore. An underlying feature of these issues is the lack of effective interaction between geologists, mining engineers and metallurgists/ process engineers. Geologists need to be more aware of ore processing issues and the range of characteristics that need to be considered as part of the resource estimate. Metallurgists need a greater understanding of the variability of the run of mine ore in terms of all the characteristics that influence the design and operation of the plant. Mining engineers need to determine the short-term variability of the ore in the mine schedule, so that there is confidence that the quality of the run-of-mine ore will be within the design specifications of the plant. A substantial overlap between these disciplines and sharing of areas of responsibility is necessary if these and other technical problems are to be better understood, production estimates are to be improved and commercial risks are to be reduced. Although the JORC Code (1999) provides guidelines for reporting all the issues that are material to an Ore Reserve estimate, some issues are rarely fully addressed in Ore Reserve reports. In particular there is no formal requirement for a metallurgist to assure his or herself of the appropriateness of the Ore Reserve classification. Consequently the level of uncertainty related to recovered grade and ore processing characteristics may be understated. It is suggested that to meet the concerns of bodies funding new mineral developments a stronger multi-disciplinary approach to the analysis of mineral deposits and reporting of Ore Reserves is required. The culmination of this approach would be the formal requirement for a geologist, mining engineer and a metallurgist to co-sign Ore Reserve reports.

Jan 1, 2002

It is usually the case that the short-term plannerÆs role is occupied by the younger site mining engineer. ThatÆs because mine scheduling is generally seen as a mundane and thankless task. But, short-term planners play an extremely important role in maximising the value of the mining resource, generally the companyÆs biggest asset. A look at any mining operation today will expose the competing drivers behind the operational and strategic plans. Operations are too often faced with pushing short-term constraints. It is the responsibility of the short-term engineer to answer the question of æWhere to next?Æ. In answering this question the young mining engineer is in an environment overflowing with urgency and constraints. Hasty decisions made at this time may have significant adverse consequences to the long-term value of the resource. Long-term strategy must address a broad and expanding number of issues that are generally overlooked by the short-term planner. It takes a holistic, rather than the prescriptive approach of short-term planning to determine the best strategic direction for the operation. To better understand the consequences of decisions made at the operational level short-term planners need better vision of the whole business. The key to improving the mining business is a planning process that integrates the short-term planners role with the overall mining strategy. Future developments in the mine planning process will focus on bridging this ædisconnectÆ between the operational objectives and the long-term goals. Improvements will come from the tools which planning engineerÆs use, and the planning methodology surrounding them. There will be significant hardware improvements to improve the speed with which a short-term planner can evaluate plausible options. Software that maximises the use of the improved hardware will be developed. Complimenting these technological improvements, conceptual methodologies of mine planning will improve to allow strategic planning to be brought within the focus of the short-term planning engineer. In todayÆs mining industry the young mining engineer is embarking on a career where business processes are paramount. This paper discusses the ædisconnectÆ that occurs today between the operational planning and long-term strategy and how this is driving developments in mine planning today.

Jan 1, 2003

The Inquiry into the 1994 accident at Moura No. 2 Colliery included in it's findings that mine escape and rescue options for persons in underground coal mines were in need of review. The Inquiry recommended the establishment of industry working groups to report to the Queensland Chief Inspector of Coal Mines on matters including escape strategy and life support for escape from mines.One of these task groups examined issues relevant to self-escape from Australian underground coal mines and formulated recommendations and guidelines in response to the terms of reference and scope.

Jan 1, 1998

By Kawatra SK

The incentive to control coal flotation circuits arises because of disturbances, from plant operating practices and variations in feed coal characteristics, which result in large amounts of fine coal being lost in circuit tailings streams and lower grade concentrates being produced. Additionally, the flowrates and compositions of con-centrates and tailings streams can have significant effects on dewater-ing brocesses. A universal control strategy for these circuits cannot be developed. Rather, three major groups of variables must be con-sidered during strategy development: coal characteristics; circuit design and operating practice; and the variables selected to control the process. The second. and third groups-are discussed in this paper and examples from studies in operating plants are presented.

Jan 1, 1985

By Armstrong A

Queensland is Australia's second largest mining state with world-class deposits of coal, base metals, bauxite and magnesite. The total value of Queensland's mining production is about $5 billion per annum, and coal accounts for around 55 per cent of that total. The environmental issues which arise as part of management and regulation of the industry are resolved within the EMOS process. The Environmental Management Overview Strategy is the cornerstone of the policy 'Environmental Management for Mining in Queensland' developed jointly by the Queensland Department of Minerals and Energy and the mining industry. The Gordonstone Coal Mine is the largest underground mine to gain approval under the new policy. Accordingly, Gordonstone has a well planned environmental management program which takes into account site-specific factors and provides for continuous compliance with the provisions of the Mineral Resources Act in a self-regulatory context.

Jan 1, 1994

The alluvial diamond deposit in the Kimberley Region of Western Australia which became to be known as the Bow River Diamond Mine was discovered in 1982 by joint venture partners Freeport of Australia Inc and Gem Exploration and Minerals Ltd. Mining commenced in 1987. This paper describes the exploration programs and results from discovery to commencement of mining and reviews the public reporting of this process in the light of 1992 Ore Reserves Code (JORC, 1992). This case study illustrates the difficulties involved in resource estimation of alluvial diamond deposits. The study also shows that current reporting standards were, to a large extent, adhered to a full ten years before the diamond reporting section to the Code was formulated.

Jan 1, 1996

By P Cheluszka, M Jaszczuk, P Sobota

This paper refers to a new idea of stereometry of cutting drums of longwall shearers designed to get medium and hard to mine coals. A new way to place picks on a drum enables to readjust a number of picks being in contact with the body of coal to shearer haulage speed. Owing to this a remarkable increase in depth of a cut within the low range of haulage speed has been obtained. On comparing operating characteristics a considerable reduction in the specific energy consumption has been shown when using the units machined as per the new idea, in comparison with the units produced in series.

Jan 1, 2003

By M T Roche

The Cannington deposit is one of the largest accumulations of silver-lead known. Located 135 km southeast of Cloncurry in North West Queensland (Figure 1), Australia, the deposit is currently in the feasibility stage of its development. The deposit is named after the nearby Cannington Pastoral Property which runs some 25 000 sheep on 'downs' country. The investigations of the Cannington deposit are carried out under the authority of Mineral Development Licences 139 and 144 and Exploration Permit for Minerals 6788, Answer Downs. Exploration for Broken Hill Type (BHT) silver-lead-zinc deposits in the Mt Isa region has been undertaken by The Broken Hill Proprietary Company Limited's Minerals Division (BHPM) since the early 1980s following in-house research which showed that the Eastern Succession of the Mt Isa Block exhibits characteristics which were favourable for hosting BHT

Jan 1, 1994

Water is required as a key strategic resource in most mining and metallurgical processes and, in some countries, it has become a limiting supply for the development of mining activity. During the last years, mining industry efforts have been successfully focused on water use efficiency in the different processes. However, these efforts will not be sufficient to compensate for the growing demand of mining products and the decrease of ore grades. New efforts should be oriented to the search for alternative water supplies such as sea water, with or without desalinisation, or water harvesting. But to survive this growing pressure and to get a social licence to operate, the mining industry can also assume a proactive attitude and pursue a prominent role in water management at regional and local scale. This paper reviews some of these emerging issues, particularly in the context of the Chilean copper industry.

Jan 1, 2009

An extensive study was carried out to evaluate the performance of Outokumpu OK50, OK38 and Maxwell MX14 cells at ComincoÆs Red Dog flotation concentrator in Alaska. Tests were conducted by varying operating conditions of the cells installed in different circuits in the plant. The hydrodynamic and gas dispersion properties were measured and the metallurgical performance of the cells was evaluated for each condition used in the tests. This paper highlights the importance of superficial gas velocity, bubble surface area flux, gas hold-up, power consumption, residence time distribution and froth flow behaviour in optimising cell performance. The findings of these tests provide valuable insights into selection of the best cell operating conditions to optimise circuit performance.

Jan 1, 2000

By W J. Bruckard, M J. Vaisey

Ashton Mining Ltd (Ashton) and Lynas Corporation Ltd (Lynas) have established a joint venture partnership to develop and process rare earth oxides (REOÆs) from the Mt Weld deposit in Western Australia. The deposit is located in a deeply weathered volcanic carbonatite structure that contains approximately two million tonnes of rare earth oxides at an average grade of 20 per cent REO. As part of the 1999/2000 feasibility study currently being undertaken by Ashton and Lynas, an extensive laboratory beneficiation test program was undertaken by CSIRO Minerals on diamond drill core samples from the Mt Weld orebody. The aim was to develop a flowsheet, based primarily on flotation that could be confirmed at pilot plant scale. The target concentrate grade was 52 per cent REO with a REO recovery of at least 35 per cent. Two main ore types, nominated as CZ (limonitic siltstone) and LI (nodular limonitic ironstone) were identified for separate laboratory evaluation. The lower grade LI-type ore overlies the higher grade and more extensive CZ-type ore. The majority of the work was conducted on the CZ ore; only limited testing of the LI ore was undertaken. The latter contains a clay component that will present difficulties in processing due to its poor filtering and settling characteristics. Two processing options for treatment of CZ ore were presented for pilot plant consideration. One (Option 1) includes gravity concentration prior to flotation while the other (Option 2) includes finer grinding and four stages of open circuit cleaning. The benefits of each scheme are discussed in detail. Neither has been fully optimised and the definitive flowsheet is most likely to be a hybrid of the two schemes, incorporating the best features of each. Typical metallurgical results from each scheme were final concentrate grades of 49 per cent REO, 10-16 per cent Fe2O3 and 3.2-4.8 per cent CaO. REO recoveries were above 35 per cent in both cases. Features of the processes developed by CSIRO were the inclusion of a gravity concentration stage prior to flotation, a modified flotation reagent scheme, a change in the method of feed preparation, and incorporation of magnetic separation to upgrade final flotation concentrates. Metallurgical results obtained from flotation tests on LI ore were much poorer than those obtained for CZ ore. The best rougher/scavenger result, with the limited amount of testing so far completed, was an REO grade of 32 per cent with a recovery of 28 per cent. Further work is needed to develop a viable processing route for this ore type.

Jan 1, 2000

The Australian lead-zinc industry faces a future in which the world market is likely to show at best only minimal growth and in which there will be increasing competition. Its production facilities use mature technologies employing expensive labour and increasingly costly energy in a country which demands the highest standards of environmental performance. Returns on investment are already unsatisfactory.Technology for survival would appear to indicate a need not only for more efficient capital, labour and energy usage combined with improved environmental performance, but also flexibility to handle more complex materials than the traditional, virtually single metal concentrates. This offers the potential for improved overall economics from the mine onwards, but will demand efficient separation and by-product recovery processes.In the lead industry these problems are being addressed in several emerging technologies. With zinc, the situation is less clear.

Jan 1, 1985

By Mould GR

Gas drainage has been practiced for many years mainly for safety reasons in various countries in Europe, in the U.S.A., the U.K. and Japan. Legislation has been developed to control the production, transport- ation and utilisation of methane and associated gases. Gas drainage is now being carried out at some Australian Collieries, but as this is a new venture little specific legislation is available. This paper briefly describes the drainage methods and legislation applied overseas, gives a brief history of gas drainage in N.S.W. and indicates the deficiencies of the present legislation. It outlines the approach to new legislation which will deal comprehensively with gas drainage operations and utilisation in New South Wales.

Jan 1, 1982

Field investigation of surface subsidence events associated with both active and abandoned underground coal mines in the United States has established criteria that enable the prediction and classification of mine-related subsidence. The key was establishing the role of geology in all types of subsidence and the recognition of beam subsidence in specific geologic settings. The classification is based on overburden thickness, variations in stratigraphy, topography and mine plan. Types of subsidence are Pit, Room, Sag, and Beam. Pit subsidence is associated with three geologic settings: shale overburden, seasonally wet unconsolidated overburden, and perched water table in unconsolidated overburden. Room subsidence occurs where the roof across the width of the room fails to the surface and a shallow depression develops.

Jan 1, 1992

"DEEPHOLE " or "Longhole" drilling is the name given to the drilling of prospecting holes with the pneumatic hammer drill. The drilling bit is of the same form, and is prepared in the same way as ordinary rock drill steel, and is extended to the bottom of the hole by sectional hollow rods, through which water is forced.The cuttings from the hole provide a sample of the ground drilled.Deephole drilling was developed at an American mine where the cost of diamond drilling, owing to loss of diamonds, was excessive, and proved very successful, holes being drilled as deep as 220 ft., in limestone, at a cost of one dollar per foot. The use of the method in other mines, and in a variety of rocks, has since been described in the technical literature. From the published descriptions the following data are drawn:

Jan 1, 1930

Dynamic hydrothermal modeling is a tool that can aid in studying problems associated with hydrothermal ore deposits and can help increase our understanding of the spatial distribution of ore within hydrothermal systems. Models are constructed by a sequence of steps involving development of a conceptual model, followed by its mathematical description in terms of governing equation with accompanying initial and boundary conditions. This equation is then solved either analytically or numerically. The four model types ò that fully describe a hydrothermal 'system are those for fluid flow, heat and ore solute transport, and deformation. At Renison, models have been used to help understand two major exploration problems. These are the controls on ore localisation in dolomite horizons and feeder faults respectively. The types of models used ò have simulated the distribution of all mineral zones, pyrrhotite, and temperature in the dolomites. This has allowed evaluation of the effects on ore localisation by physical and chemical heterogeneities within the dolomite host rocks, and allowed estimation of potential controls in different physical and chemical environments.

Jan 1, 1987

By Croggon R

Passing a direct current through a jointed fine grained soft rock mass auses the movement of water by the process of electric-osmosis. There are other processes such as electrolysis which transport ions that interact with associated ions and can, in turn, be oxidised. This results in the dissolution products being transported towards the cathode electrode. In the cathode region the ferrous hydroxide is oxidised to ferric hydroxide %%ith consequent precipitation. The cracks and joints are current pathways, along which the ferric hydroxide is deposited. This deposition reinforces the joints and increases the shear strength. By adding calcium chloride to the anode, the rate of corrosion is increased with the concomitant increase of deposited ferric hydroxide along the joints. This, in turn, significantly increases the joint shear strength. The process is pervasive in that the current via the water paths travels through the crack and joint systems The result is that not only specific joints are reinforced but the cracks and mtciconnected voids are also reinforced.

Jan 1, 1997

By Trevits MA

The United States Steel Corp. in cooperation with the United States Government is conducting a large-scale methane drainage field demonstration using stimulated vertical boreholes drilled in advance of mining. A grid pattern of 23 boreholes, isolating approximately 1.5 km2 of coalbed area, has been drilled to the lower bench of the Mary Lee coalbed, Jefferson County, Alabama. Upon completion of drilling operations, various hydraulic stimulation treatments utilizing nitrogen-generated foam, water, and gelled fluid were performed to enhance the rate of methane gas removal. Production from the grid pattern began in September 1977 and continued as the last borehole was placed on production during October 1980. To date, in excess of 33,800,000 m3 of methane gas has been drained as a result of this effort. Underground mining operations were approximately 3.2 km from the grid pattern when production began and have currently progressed to within 1.6 km. Underground interception of the grid is expected in 1986.

Jan 1, 1982

By A B. Bell

The health and in some cases survival of mineral exploration and mining companies is, in today's markets, more dependant than ever on the effective use of information technology. The need for speedy collection, organisation, maintenance and distribution of corporate and project information is a phenomenon that will continue to strengthen with market thirst.Geographic Information Systems (GIS) provide a medium for storage, maintenance and retrieval of data, and Internet Mapping adds a technology for effective distribution of that data. Combining these technologies can return benefits both fiscally and technically by reducing costs of ownership in IT infrastructure and increasing the efficiency and effectiveness of both internal and external information delivery.GIS and Internet Mapping technologies have reached a practical stanza in their evolution and will continue to develop as a key business tool in the natural resources sector.

Jan 1, 2002

Your Worship the Mayor, Ron McCullough; the Honourable Tony McGrady M.L.A., Minister for Minerals & Energy; distinguished guests, ladies and gentlemen.It's both a pleasure and a privilege to have been invited by the North West Queensland branch of the AusIMM to speak at a forum in Mount Isa to discuss the potential, and more importantly, the development of the great North West. I spent 25 years of my life proudly living and working in this part of the world, marvelling at its riches, exploring its potential, assisting in its development and responding to its challenges.As President of the North West Queensland branch of the AusIMM in the early 1970's I can clearly recall helping to organize a major symposium extolling the geological potential of the region, revealing the extensions of the Mount Isa copper orebody at depth and describing the potential of the then untapped Hilton Mine. Our optimism in the North West so obviously reflected two decades ago remains today.

Jan 1, 1993