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By Dredge K, Becker G

The successful dissolution of the valuable metal components of a solid phase is often a basic requirement for a successful hydrometallurgical treatment process. Sulphide concentrates are often an intermediate product in the production of refined metals. These concentrates need to be further processed to realise the contained metal values in a useful form. Pyrometallurgical techniques have tended to dominate, at least the initial treatment of metal sulphide concentrates. The technology described, Activox«, has been developed specifically for the hydrometallurgical treatment of these sulphide mineral concentrates, in particular those containing copper, nickel or gold. The Activox« dissolution technology coupled with the use of existing, or newly developed, downstream processing techniques, offers alternative processing options for the recovery of full value, saleable metal products. The technology is suitable for application down to relatively small scales opening up the opportunity for on-site production of metals even at modest scale mining Operations.

Jan 1, 1995

By T Laurencont, C Unger

The Mount Morgan minesite, located approximately 40 km SW of Rockhampton in Central Queensland, comprises 270 ha of unrehabilitated land which is the currently the major source of acid mine drainage run-off and seepage to the adjacent Dee River. Additionally, the minesite hosts an Open Cut Pit which contains 9000 ML of acidic and metal-rich water. In the absence of active management of water in the pit, there is a 50 per cent probability of an uncontrolled spill occurring in future years. The development of a contingency plan for management of overflow from the pit in the short term, has incorporated findings from numerous studies relevant to the Open Cut Pit including, but not limited to, water balance, contaminant source identification, toxicity testing, water quality profiling and limnological modelling, and estimates of probability of overflow. Extensive stakeholder consultation and peer review were also undertaken during the formulation of the contingency plan. The medium-term goal of lowering the water level in the pit to reduce the current high probability (50 per cent) of uncontrolled overflow to acceptable levels of risk is proposed to be achieved by a campaign of chemical water treatment. The treated water will be discharged to the Dee River, and sludge returned to the pit. The methodologies used for the selection and development of the water treatment process, that is proposed to involve treatment with lime, are described. Water treatment is the short- to medium-term component of a long range rehabilitation plan for achieving a negative pit water balance, and sustainable management of acidic water across the whole site. Achieving this ultimate goal will involve: reducing the inputs of water to the Open Cut Pit such that the annual water balance is zero or net negative, thus removing the need for water treatment in perpetuity; maximising, by surface rehabilitation works, the quality of run-off reporting to the Dee River; and minimising the volume of acidic seepage reporting to the seepage interception system. Possible strategies for achieving this long range goal consistent with overall site rehabilitation objectives are currently being developed and costed.

Jan 1, 2003

By Nightingale R, Johnson B, Bensley C, Vince A, Keast-Jones R

In order to counter the massive increase in the level of near gravity material that would follow the reduction in dense-medium cyclone separation density at B.H.P. Slab and Plate Product Division's B and C coal preparation plants, "wing tank" systems to control medium density to within ¦0.005RD units have been installed. However, despite very precise density control, cyclone metallurgical performance has been less than satisfactory. The approaches taken to identify the causes of this poor performance and to justify alterations in operational and maintenance practices are presented.

Jan 1, 1987

By Hill J. R M, McDonald M. M

A prediction technique for support perfor- mance of hydraulic backfill in narrow stopes is applied to two stopes separated vertically by a sill pillar. Predicted stope wall closures and fill pressures compare favorably with field measurements taken over a period of several years at two mines in the Coeur d'Alene dis- trict. Stope wall closure and peak pillar stress can be substantially reduced by improved fill quality within a practicable range of fill and rock properties.

Jan 1, 1973

By B Arthur, K Sexsmith, D Hockley, S D

At the proposed Crandon Project, mill tailings would be depyritised for upland disposal. The resulting pyrite concentrate would be disposed of in the underground workings as a cement-amended paste backfill. In the long term, the underground workings would be flooded and the potential for the paste backfill to generate acid would be limited. However, while the mine is operational, there is potential for oxygen ingress to the backfill that may lead to sulfide mineral oxidation and acid generation. A series of humidity cell tests were completed to assess the potential for groundwater contamination. To assess effects of surface area on oxidation, the humidity cell tests were conducted on moulded cubes of paste backfill. The tests were terminated at different intervals, and the cubes were dissected and examined mineralogically. Various leach extraction procedures were also used to assess the progress of oxidation and secondary mineralisation within the paste backfill. The test results showed that: the cement amendment significantly contributes to acid neutralisation and results in a lag in excess of one year before the onset of acidic conditions (in comparison to less than three weeks for the pyrite concentrate); the depth of oxidation in the paste backfill is restricted to about 1 mm after 107 weeks of testing; and secondary minerals form a distinct ærindÆ at the surface of the paste backfill. The results indicate that acid generation in the backfilled stopes would be minimal. The importance of including the surface area effect in the testing (ie using moulded cubes) is clearly demonstrated.

Jan 1, 2003

By Rigby D, Gould K. W, Hart G. H

The variation in chemical and isotopic composition of hydrocarbon gases generated from humic source rocks in the Cooper Basin, the orth West Shelf, the agoorin oil shale deposit. ollinsville and the southern Sydney Basin is reviewed, discussed and interpreted.The primary composition of gases generated in and released from such source rocks appears to be very largely controlled by the degree of dispersion of the organic material. For example in eoaly shales, where the degree of dispersion may be high, products as generated may escape into surrounding inorganic structures where further maturational reactions may proceed. On the other hand, when the organic materials occur in massive form, as in coal seams, the hydrocarbons generated tend to be retained within the coal. Further cracking to the stage of methane generation is usually required before release of hydrocarbon products is significant.Secondary factors of importance in determining seam gas composition in the Bowen (Collinsville) and southern Sydney Basins are the invasion of coal measures by carbon dioxide from external magmatic sources and/or the vertical diffusion and loss from the surface ofgases generated at depth.Isotopic measurements of gas composition have been particularly valuable in determining the origins and histories of the gases examined, in demonstrating when gases are of mixed origins and in the prediction of gas quality in exploration.

Jan 1, 1985

By A Jurg, F Leclercq

The total drill and blast concept is widely known in the mining industry. On the contrary, the quarry industry rarely adopts such working methods. Based on the experience of the CBS quarry in the North of France, this paper shows how up-to-date blasting technology and simple control methods can significantly improve the overall Mine to Mill efficiency of a quarry. The CBS quarry, in partnership with the EPC group and Nitro- Bickford Company, adopted a new working process three years ago aimed at increasing blast performance and related productivity of the downstream process (loading, hauling and crushing). The pattern geometry of each blast is controlled and explosive charging is carried out following the æconstant specific energyÆ CSE concept. This method provides a homogeneous fragmentation distribution and reduces vibration peak-particle-velocities. The impact on downstream productivity is controlled by means of a simple information management system, which collects and measures key parameters of the production process such as; hauling cycles, crusher throughput, secondary breaking and vibration peak particle velocity. This information system has clearly proved over time that consistent blast quality could be achieved, leading to a 30 per cent improvement in quarry productivity. Improved energy control of blasting through optimisation with electronic detonators, allowed a significant reduction in vibration impact on the environment. Improvement in blasting security, reduction in the environmental impact and productivity enhancement are major benefits that quarries can obtain from these CSE optimisation blasting methods.

Jan 1, 2007

This paper briefly discusses the negotia- tion of the more important provisions in agree- ments for exploration and mining rights with Pacific countries. LAND RIGHTS Land rights are complicated and sometimes controversial in many of the Pacific countries. In some countries, a company will have to deal with land owners directly; in others, the government will act as intermediary. Inevit- ably, a company will have to deal with both. Mining companies need to be sensitive to the culture and particular interests of the land owners and of their history in defending their rights. The issues are too complicated to be dealt with here. Some mining companies have spent, and will continue to spend, considerable time trying to understand them. It will " require patience, perseverance, sensitivity and unflagging optimism. The better advised companies will ensure that their local repre- sentatives get to know the land owners, under- stand their concerns, and will pursue a policy of keeping them informed on a regular basis of all of the company's activities and proposed activities. Good community relations are the keystone for good mining operations in the Pacific. Most countries will require the submission of an environmental impact statement so that they will know in advance what effects a pro- posted mining operation are expected to have on the environment and how it is intended to deal with them. They will also want to approve the company's environmental reclamation and rehabilitation plan. Let's face facts right away - mining, by its very nature, is not going to improve the environment. There will be waste discharges, emissions and deposits. They will affect the land, air and water and hence human, marine and animal life and vegetation. There will be sounds and odours and the esthetics of mining operations, though perhaps pleasing to geolo- gists and mining engineers, will not please Others.

Jan 1, 1987

In June 1992, the High Court of Australia recognised native title of the Meriam people over parts of the Mer Island in the Torres Strait as a form of common law. The Court also indicated that native title may have survived European settlement of the mainland Australia where it had not been extinguished by Governments and Aboriginal people have maintained their traditional connection with the land. The decision meant that two systems of land law were seen as existing side by side in Australia: ò one which derived from grants from the Crown under laws passed by Parliament; ò another which derived from the diverse laws and customs of the many Aboriginal groups in Australia.

Jan 1, 1996

The excavation of a tunnel through rock and mixed ground of basalt and silty clays presents a challenge to engineering organisations. Such was the situation facing the Melbourne and Metropolitan Board of Works (MMBW) in constructing the 15.3 km, 5.5m dia. tunnel component of the new Western Trunk Sewerage System. The tunnel geology showed that there were two distinct components to the excavation - rock and mixed ground. By drawing on extensive experience in the use of Tunnel Boring Machines (TBM's) used previously by the MMBW and using techniques developed for predicting TBM per- formance, a comparison of the options of drill and blast versus TBM was made. The conclusion was that TBM methods would provide the best solution to the problem. Tenders were called for the supply of a TBM. A performance specification was used to attract tenders offering designs which re- flected the state of the art on an internation- al level. Particular features required by the MMBW were included in the specification. The excavation planning and operation are described in this paper. The production achieved has shown that the TBM can very adequately handle rock excavation (best weekly production 167.9m). Extreme conditions of mixed ground with heavy groundwater inflows have been handled using an auxiliary thrust system to maintain gripper reaction through the soft ground encountered.

Jan 1, 1987

The overall systems approach to blast furnace aerodynamics is explored including the time and spatial inter-relationships that exist between the furnace lines, tuyeres, burden characteristics, distributor capabilities and furnace operating practice. Attention is called to the time dependent, three dimensional aspects of blast furnace aerodynamics and to the existence of several zones within a furnace where the flow characteristics are different. Changes in furnace operating practice to take further advantage of fully beneficiated burdens including formed coke are discussed from a practical viewpoint. Lessons learned in a variety of shaft furnaces used for other purposes are discussed insofar as they have a bearing on aerodynamics in an iron blast furnace. Questions are raised about the penetration of hot blast in large furnaces. Operating practices and.proposed solutions are evaluated where tuyeres over iron and slag notches are restricted or plugged. Opportunities are presented for using on-line hierarchical computer systems with adaptive tuning algorithms to provide non-linear control of changing process conditions in real time. This will make it possible for the blast furnace operator to optimise a variety of interrelated paramaters, each with different response times. Potential increases in productivity, fuel savings and improved quality control are believed to be within reach.

Jan 1, 1975

By J McNee

Pike River Coal Limited (PRCL) is developing the Pike River Coal Mine in the Paparoa Ranges of New ZealandÆs South Island. The mine is being developed to extract a coking coal deposit of the Brunner Seam, some 46 km northeast of Greymouth, using a combination of continuous miners, road-headers and hydraulic extraction.   The mining area is located within Department of Conservation (DOC) land and is adjacent to the escarpment of the Paparoa Range and the Paparoa National Park. The mine will use its elevation advantage to hydraulically flume coal from the working faces to the pit bottom area where it will be slurried to approximately 35 per cent density of solids and pumped down a slurry line to the coal prep plant some 10.5 km down the Pike River Valley. The coal will be sold on the export market as a high quality coking coal for international steel making.   PRCL faces significant challenges to achieving the goal of cost effective production. The remoteness, high rainfall (greater then 6 metres per year on average), temperature variation and restrictions on access to this subalpine environment have driven the project to develop some distinctive solutions. These include the establishment of survey control in such a difficult environment with vertical and sub-vertical rock faces, significant vegetation and steep slopes by using helicopter survey, aerial photography and LIDAR (Light Detection And Ranging) aerial survey. PRCL has also commenced designing the placement of the main ventilation fans in an underground chamber in the stone drive.

Jan 1, 2007

With the theme of û æUnderground Ore Handling SystemÆ, Kopanang Mine completed an extensive project on a specific system with technologies for the handling of ore from a dedicated drawpoint to the shaft system. The intended rail haulage tramming system had to be capable of handling the shaft design and Life of Mine (LOM) requirements. Kopanang is an AngloGold Ashanti gold mine situated in the province of the Free State in South Africa. In the Sotho language the name æKopanangÆ means to come together as a team. ItÆs an appropriate name given that 25 companies worked on this project. The future focus at Kopanang is to establish four mining levels between 3 to 4 km south-west of the shaft and two mining levels to the west. The mine has an expected life of almost 20 years and capital was approved in order to access this reserve to establish the infrastructure to handle the ore, hence this exclusive rail haulage tramming system of close to R40 million (SA rands), which took three years to construct. Apart from the fact that this system had to be capable of handling 6500 t per shift at a depth of over 2 km over a length of 3.2 km, some of the major considering factors were: safety, economic factors with improved labour productivity, efficiency and reliability, risk termination, and ergonomics. The system comprises two 20 t locomotives operating in a double header configuration from a dedicated draw point to a dedicated tip area for the reef and waste ore. With the objective of handling high speed and high capacity, this 200 t payload train is capable of running at 35 km/h powered from a 500 volt ac overhead line. Each loco consists of two 90 kW dc motors with ac/dc power conversion on the locomotive. For the system to operate at this speed, the rail system is constructed with Class 1 rails over the entire hauling distance. The tipping mechanism is unique and the span of 11 hoppers each with a load of close to 20 t is capable of tipping the pay load of 200 t in about 20 seconds hands free.

Jan 1, 2005

The most frequent initiation of coal dust explosion results from the ig- nition of high methane volumes, often at low concentration close to the minimum flammability limit, by a weak ignition source, e.g. frictional sparks. Tests performed in the 400 m underground test gallery of 7.5 m2 cross section indica- ted the following: 1. Methane at 200 m3 volume and con- centration 4.0 - 5.0 % CH4 may initiate the coal dust explosion. 2. Suppression of explosions result- ing from such initiation is very difficult, even when employing triggered, barriers.

Jan 1, 1988

Thank you for this opportunity to address your conference on The role of coal in the New Zealand energy market".New Zealand's energy market has, in common with much of New Zealand, undergone major change following the market reforms of the Labour Government.As far as the energy sector is concerned this change has been for the better, as it has created for the first time in a very long time a "true economic market" for energy in New Zealand.

Jan 1, 1990

By Chamberlain A. C, Fisher N, Avraamides J

The thermal decomposition of sodium ethyl xanthate (SEX) adsorbed onto activated carbon was studied by coupled thermogravimetric analysis-Fourier transform infrared spectroscopy (TG-FTIR). Two discrete mass losses were observed, in the temperature ranges 100 - 230¦C and 200 - 340¦C. The same two gases, carbonyl sulphide (COS) and carbon disulphide (CS2), were the main gases evolved in each of the mass losses. Samples of activated carbon from two industrial plants were obtained and analysed by TG-FTIR. COS and CS2 were not detected in one of the samples. The other sample did show evidence of COS and CS2, which indicated that fouling of the carbon by SEX was still present. Other organic compounds were detected in the evolved gas stream of both samples, indicating the presence of organic reagents other than SEX.

Jan 1, 1996

By Landy D. M, Ward M. O, Power W. L

Geological structures are irregular and intricate, so creating a 31) solid geology model is a complicated process. A software system can only partially automate this process, since geological knowledge and experience are required. Therefore, the interaction of a geologist is critical for such a system. This paper discusses some useful advanced functions for enhancing the visualisation and manipulation of 3D solid geology models: flexible attribute display, multiple views, auxiliary display objects, and geologically sensitive operations. It also describes some experiments to explore the effectiveness of these functions and presents sample output. Most existing 3D solid geology modelling systems are implemented in an ad hoc way, which greatly reduces their reusability and extensibility. This paper presents a generic framework for 3D solid geology modelling systems, which is based on object-oriented technology. The deficiencies of current systems may be improved by using this generic framework. A modelling process based on drillhole data is discusses as a case study.

Jan 1, 1995

FOR some time past keen interest has been shown in both America and South Africa in the mining drill-steel problem. This interest has extended to Australian mining fields, and Australian drill users, ever desirous of increasing efficiency, are vigorously attacking the problem. The writer has recently been engaged in the investigation of the problem on two of ,the biggest mining fields in Australia, and has formed very definite conclusions concerning the causes of many drill-steel casualties. He puts these views forward in the hope that they may be of interest to, both drill manufacturers and drill users. The subject is here dealt with mainly from the aspect of the properties of the steel and the modifications of these properties whensubjected to various manipulations. It is generally admitted that the drilling machine has greatly increased in power and efficiency during recent years, and the consequence is that the machine is demanding better service from the steel. This is being impressed on the drill users by an increase in steel casualties. This fact has led many mining people to the view that the machine has developed so rapidly that the steel maker has not been able to keep pace, and that consequently the steel isfailing by fatigue 0:1; so-called crystallization. This view is rather depressing. The writer, on the other hand, is inclined to discountenance fatigue as a serious factor under good normal working conditions where the steel is carefully manufactured and supplied to the user under suitable structural and sound conditions, and has subsequently received kind treatment at the hands of the drill sharpener and the drill user.It is not reasonable to attribute failures to fatigue until it has definitely been proved that the steel is fundamentally sound and is in the best structural condition to resist the stresses it is called upon to withstand, and, this being so, that all fundamental principles of...

Jan 1, 1923

By Walker K, Burton RC

An outline of the ventilation and refrigeration requirements of deep South African gold mines is presented. This is followed by a brief description of the history of controlled recirculation in mines and the practical and economic benefits such schemes can offer. The potential hazard of a fire in a recirculation system is discussed.The major part of the paper describes the first large-scale field trial of controlled recirculation to be conducted in South Africa. Emphasis is placed on the monitoring system that was used for data acquisition during the trial, and also on a safety system designed to shut off the recirculation fans in the event of a fire.The paper concludes with a review of the latest development work taking place on recirc-ulation safety systems.

Jan 1, 1985

By Freeman N

A microcomputer based control system has been developed and implemented at ZC Mines (now Pasminco Mining). The control system maximises throughput at a product size set point while maintaining a "safe" cyclone underflow and mill operating pulp density.To characterise mill and cyclone operation over a range of ore types, 60 circuit surveys were carried out by ZC Mines personnel over a period of four months. The data for each test were model fitted to check for data consistency and to accurately estimate circulating loads.The model fitted results were combined with instrument readings (including in-stream analysis probe assays) and the data checked for ability to predict key variables such as product size and underflow density from measurable inputs.In the resulting control scheme, panicle size and underflow density are not monitored directly, but are predicted by regression equation models based on directly measured variables. The tonnage control loop uses a dynamic model to maximise responsiveness.The system provides a data log output to an mM compatible personal computer at programmable intervals. Comparative data logging over a period demonstrates substantially smoothed circuit performance.The grinding control system was originally implemented using Fischer and Porter micro-DCI controllers. The program has also been implemented on a distributed control system using a sequence oriented programming language.

Jan 1, 1990