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By I Villalba

The need to continue the development of the Ensham mine has led to blast up to 75 m to the Eastern side of a water dam in the vicinity of Ramp 23. The water dam wall is exposed to blasting over a distance of approximately 500 m. The first decision was to determine that the existing rock pillar between the Eastern side of the water dam and the blasting operations may not be less than 75 m in order to minimise the damage that the blast could generate to the dam wall. It was also necessary to define blasting practices to minimising the blast damage to the rock properties of the dam wall and to avoid adverse effects from vibration and gases generated by the detonation on structures.For this purpose analytical designs and test blasts were conducted to assess the ground vibration attenuation within the rock pillar. From this analysis, it was concluded that the best practice to reduce the rock damage was to create a zone of fractured rock adjacent to the side of each production blast. This fractured zone would create an effective filter both for vibration and for gases generated by the blast. This zone of fractured rock was created by firing two buffer rows. In terms of pattern size and powder factor the two buffer rows were designed just to generate a fractured rock zone. To date approximately 500 m have been excavated along the eastern wall of the water dam where each production blast was preceded by a Trim blast. This practice has given good results with regard to minimising the damage generated by production blasting.

Nov 8, 2011

Designing and constructing OxianaÆs Sepon gold and copper operations in one of the most remote areas in Laos has been a great achievement; one which was recognised by the engineering industryÆs highest accolade û the Australian Engineering Excellence Award in 2005. The developing nation of Laos has no previous mining or heavy industrial experience, but the support of the Lao Government and a remarkable Lao workforce has enabled the project to be developed and operate as well as it would anywhere else in the world.When making a decision to invest offshore, several geophysical and jurisdictional criteria need to be considered. Laos offers unparalleled prospectivity, a central location with growing infrastructure, a ready workforce and a developing but supportive regulatory regime. In addition, the Sepon copper project has exceptional characteristics, including its high grades, location near the surface, leachable qualities, access to hydropower and the ability to produce cathodes on site. These attributes and its location in the centre of a region hungry for resources contributes to the projectÆs excellent economics.

Jan 1, 2006

By J P. R de Villiers

The Vanderbijl Park sinter plant in South Africa was investigated to determine the reason for the production of very fine sinter not acceptable as feedstock for the blast furnace. A procedure was designed to generate representative samples and to prepare the samples for chemical and mineralogical analyses. Results from a mineral analyser showed that the samples are extremely heterogeneous and therefore the sampling and sample preparation methods had to be tested in order to produce representative samples. The high production capacity at the sinter plant could also give rise to sampling errors. The method designed involved sampling of the conveyor belt at the sinter plant every four hours for the duration of three days. The samples were then milled and split into smaller sections appropriate for analysis. X-Ray diffraction (XRD) and X-Ray fluorescence (XRF) analyses were conducted on the samples. The results showed a standard deviation of less then one per cent, which indicates that the samples were representative and that the method used was therefore adequate. Systematic differences in the phase proportions between normal and fine sinter samples were detected, with the fine sinter containing more haematite than the normal sinter. The sampling method employed gives added confidence that the differences are real.

Jan 1, 2008

QEMSCAN« technology is a widely accepted automated e-beam technique providing quantitative and statistically robust mineralogical data to the mining industry. It uses X-ray mapping combined with backscattered electron (BSE) brightness to identify minerals in almost any type of geological material (Gottlieb et al, 2000). Besides the modal mineralogy also the liberation, associations, average grain size and other textural information can be obtained. The aim of this study is to test reproducibility of this technique by setting up and running standard tests on different QEMSCAN« systems. Multiple sample blocks were prepared by our standard operating procedure as epoxy-mounted, carbon-coated, polished blocks. The replicates were measured under the same conditions and measurement parameter settings on different QEMSCAN« instruments. The relative standard deviation (RSD) for the set of measurements was calculated. Generally the reproducibility of the systems themselves was found to be excellent, ranging between 0.4 and 1.5 per cent RSD. The more significant change in the reproducibility was found to be caused potentially by the sample preparation and variation in the mineralogy of the replicates. The measurement parameter settings together with these variations can account for almost 15 per cent RSD for minerals of low abundance. For analysed samples good results for the main phases present in quantities higher than 2 - 5 wt per cent of the total mass of the sample were confirmed with RSD generally below six per cent. Following the experiments, the parameters having the biggest influence on the performance of the QEMSCAN« and its precision are discussed in detail. The importance of sample preparation procedures and measurement parameter settings is emphasised. It is shown that experience and excellence is necessary for getting the most from the automatic mineralogical methods like QEMSCAN«.

Jan 1, 2008

Mineral processing is at the hub of the exploration-mining-metals production system. Because of the large volumes of material processed, incremental technology investments can pay off better than for other parts of the system. However, much of mineral processing remains a 'black art', because we are behind in investing in modem technologies. Consequently, we have one of the best opportunities to improve efficiency and competitiveness through the application and transfer of technologies that have already been developed for other industries. The reluctance of minerals companies to place priority in our area is not because we lack new ideas; our senior management has not been convinced, based on our previous results, that such investments will pay off as well as other investment opportunities competing for the same resources. The key is the proper establishment of technology strategy and more effective transfer of technology. The presentation will identify the failure mechanisms of technology transfer and will present a model for improving the success rate, a prerequisite for raising the priority of mineral processing investment. Topics emphasised include strategy formulation, human resources planning, and total quality management principles applied to improving technology transfer.

Jan 1, 1993

By J Brown, C Roberts

The scope of this paper is to recount the development of segmental linings used in tunnel construction, starting with its inception as an improvement to the brick-lined tunnel approach of Brunel in England and moving through the history and development to the present day, before finishing with a few insights into what the future might hold. The paper also discusses the motivation for the relatively recent move towards replacing conventional steel reinforcing cages with steel fibres and the reasons why steel fibre reinforced concrete (SFRC) is rapidly becoming the material of choice for manufacturing precast concrete segmental linings.

Jan 1, 2008

Unprecedented political, economic, and social change throughout the world will have an increasingly profound effect on the dynamics of the world's mining industry. Analysis of the early financial trends in this development (statistics on exploration expenditure, and investment flows) gives some insight into the magnitude of structural change and its implications for established mining economics and companies.Increasing confidence in the stability of many third world and developing countries is attracting exploration and investment capital that had previously been largely directed to established mining economies in North America, Australia, Europe and Southern Africa. Some of the projects requiring capital and technology in the CIS, Africa and Latin America are technically very attractive. The end of the 'cold war' and the influence of the IMF is gradually changing their risk profile for mining investment.

Jan 1, 1993

Hindustan Zinc Limited (HZL) is one of the leading base metal producers in India. It operates a two-smelter Complex at Visakhapatnam, Andhra Pradesh. At this zinc-lead smelter zinc is manufactured by the conventional hydrometallurgical route and lead is produced by Blast furnace technology generating residues or wastes which contain substantial quantities of metal values. Disposal of such wastes is a problem in any non-ferrous industry. Both the stringent environmental regulations and the changing industrial scenario emphasise the need for industrial research to find economically viable and environmentally friendly technologies to recover the metal values from these waste materials. The in-house R&D Centre at Vizag Zinc Smelter (VZS) thinking globally re-engineered its activities and major thrust was given for converting waste to valuable metals and metal compounds. Basic analytical chemistry with the hydrometallurgical concepts has been adopted in developing these innovative technologies. In this paper attempts are made to provide a clear history of the different waste raw material, the process developed for each raw material and their superiority of over other parallel work. Most of the processes described here are pilot plant tested and under patenting. The process flowsheet, results obtained and advantages of each process are presented. This paper provides a consolidated approach through which the varied smelter waste materials can be processed with cost effective and eco-friendly innovative technologies. In-house R&D efforts at VZS with its contribution and achievement in converting æwastes into wealthÆ technologies are presented in this paper on the following the major thrust areas:recovery of zinc from liquid effluent; recovery of zinc from effluent treatment plant (ETP) gypsum sludge; production of highly pure electrolytic zinc metal powder from zinc bearing gypsum residue/sludge generated at the effluent treatment plant; hydrometallurgical recovery of copper as copper sulphate solution which can be used for CuSO4.5H2O, copper cathode/copper metal powder from copper-cadmium cement; recovery of manganese, lead and silver from anode mud generated at Zinc Cell House and 4-metal extraction/recovery of manganese, cobalt, copper and nickel from Indian ocean bed manganese nodules; recovery of zinc, lead, silver and sulphur values from silver concentrate residue generated at the froth flotation process; recovery of silver and lead as lead-silver sponge/lead-silver sulphide concentrate from lead bearing residues; recovery of lead, silver and copper from copper matte; recovery of antimony as antimony metal or lead-antimony master alloy from antimony bearing dross; and recovery of nickel and dimethylglyoxime from Ni-DMG complex.

Jan 1, 2000

Developing and operating mines in developing countries is never dull, but continuously challenging in terms of geology and terrain, geography and location, culture and land tenure, environmental and social issues, fiscal regimes and in some cases political risk. In addition, the rapidly changing nature of the communities with little understanding of the nature of mining at the community level requires us to continually manage issues affecting project development and mine operations with greater sensitivity. In frontier regions, people skills can become more essential than technical skills, particularly in dealing with indigenous people. Hence, managing a mining project requires a huge relationship effort.Effective communication with communities of different cultural background and proactive management of issues influencing community aspirations and desires requires not only new skills but also creativity with new concepts on how to deal with social issues under a different cultural context. The involvement of government agencies and NGOs is an important ingredient to creating understanding and collaborative approaches to common social issues. Maintaining stakeholder relationships pays in the long-run and is a useful exercise in getting information feedback from the wider community.

Jan 1, 1997

By S C. Sc, J Young, N Belluz, D Nicholas

The heavy sulfide zone (HSZ) of the Grasberg deposit has the geometry of a funnel and is located at the contact of the mineralised intrusive and the relatively barren sedimentary rock types. The geometry and the rock properties associated with the HSZ plays a significant role in pushback design and sequencing. Most of the HSZ has relatively low strengths which must be considered in slope design and management. This paper presents the open pit mine geotechnical and planning design considerations associated with the HSZ.

Jan 1, 2007

The first stage in the refining of lead blast furnace bullion is the removal of copper and is normally done as a batch process in open kettles.A number of attempts have been made to establish continuous processes operating in reverberatory type furnaces, but the growth of accretions in the furnace has always presented a serious problem.The Broken Hill Associated Smelters Pty. Ltd. (RH.A.S.) at Port Pirie have overcome this problem by constructing a reverberatory furnace and ancillary cooling system of a novel design.Although a number of mechanical and metallurgical problems still remain to be solved, it is claimed that a workable continuous copper drossing process has been established.INTRODUCTIONLead bullion emerging from the blast furnaces at Port Pirie is at a temperature of about 1100°C and contains, among other impurities, about 1 per cent of copper.The first stage of refining is the removal of this copper by a drossing operation and in the past this was done, batchwise, by allowing the bullion to cool back in 100 ton kettles.At about 700°C, copper dross begins to separate as a crust on the surface of the kettle and this separation was allowed to continue down to about 450°C when the crust was brokenup and skimmed manually using a long handled, balanced, spoon. The dross was then smelted in a reverberatory furnace to produce a saleable copper matte and separate out lead bullion, which was returned to the drossing kettles. The copper content of the drossed bullion was then further reduced by a sulphur treatment process.The drossing operations involved hard manual labour under arduous conditions and the pouring of hot bullion into...

Jan 1, 1963

Today's emphasis on the enterprise bargaining process must be seen as an opportunity for organisations to further develop occupational health and safety standards at work. In particular, this shift from a centralised industrial relations system to employer, employee bargaining, presents organisations with an excellent opportunity to develop OH & S at the `shop floor' level. This is despite real difficulties in presenting hard data on the cost benefits. Unfortunately, examination of enterprise agreements ratified by the Australian Industrial Relations Commission (AIRC), show that less than 32 per cent contain provision for occupational health and safety. Those addressing the issues of occupational health and safety have included segments such as: ò rehabilitation activities; ò a new emphasis for workplace occupational health and safety committees; ò formalising procedures related to hazard identification and control; ò the use of personal protective clothing; and ò occupational hygiene and health monitoring issues. For example, an enterprise agreement reached between CIG-Gases and their unions, included clauses which commit employees to attending ten safety meetings and two work place inspections each year, in order for them to receive any further pay rises.

Jan 1, 1995

By Davies L, Jeffreys J

The Broken Hill Proprietary Company Limited (BHP) has been successfully using mini computers in its open cut strip and pit coal planning for the past six years. A recent development within the computerised Seam deposit User oriented Mine Planning System (SUMPS) provides the facility for the generation, evaluation, and simulation of colliery workings.Existing computer programs for collieries were studied, but none met the requirements of BHP's underground mine planners.Consequently, it was decided to develop programs, based on those existing within BHP for open cut strip and open cut pit mine planning. The new planning facility was designed to enable any number of proposed colliery developments and operating plans to be evaluated against optimistic, most likely and pessimistic geological lease area interpretations.In mine planning, sensitivity studies should be conducted to determine the likely effects on production, development costs and colliery economics of changes in mine design and budgeted equipment productivity. By automating the manual calculations involved, the computer programs provide the ability to conduct numerous and extensive sensitivity studies. Hence an optimum mine design for budgeting purposes can be derived quickly with an improved degree of confidence in the long term viability of the proposed development.

Jan 1, 1982

By Stuedel J

Starting from comprehensive programme systems for monitoring tasks of any kind, this paper follows the steps of the programme system hierarchy from top to bottom. The monitoring and control centres for entire production units, the subordinate centres, i.e. district control centres, the microcomputer based autonomous control systems, and data input by mobile terminals are discussed. To an increasing extent, the main emphasis is shifted from monitoring and control of individual machinery to optimized operation of extremely complex comprehensive systems. Network displays, for instance displays of production, transport, supply- and evacuation-networks as well as of safety systems, gain increasing importance. Personnel deployment systemsand planning networks as well as stocktaking and accounting are more and more closely linked with the above-mentioned networks. In order to keep development and application (purchasing) costs low, and to assure compatibility, the use of standard modules is to be assigned particular importance. New module developments are introduced, and the design of standard interfaces for computer and module coupling are discussed.For conclusion, a short view is given on the opinion of the line manage-ments on how future hierarchic systems should be featured in terms of individual units and overall systems, and used.

Jan 1, 1985

By Penney B. K, Baghdadi A. A

An electron probe micro-analyser, controlled by a dedicated mini-computer,has been operating at Imperial College since 1970. The data assessment capability of the computer was limited and, in order to make better use of the information produced by the analyser, extra computing facilities were needed. Following the initiation of a Laboratory Automation Project at Imperial College involving the use of a central computer linked to laboratory type computers and to further more powerful systems,it became possible to carry out much more detailed and extensive mineralogical analyses by connecting the mini -computer to the Laboratory Automation Network. The paper describes the techniques employed including hardware, software, inter- connection, analysis and operating methods.

Jan 1, 1977

By H Bleuler

A new portal and access drift was constructed by Concrete Constructions for BHPÆs Elouera Colliery, south of Wollongong.The portal area at the base of the Illawarra Escarpment is in soft colluvium material, underlain by highly to moderately weathered sandstone. The area has a well documented history of slope movement or slope creep and one of the main criteria for the design was to minimise disturbance to the unstable slope by limiting the excavation for the portal establishment. This was achieved by incorporating a sloped headwall and gabion wingwalls to accommodate the anticipated creep and groundwater seepage.Main features of the design process also included the provision of both primary and secondary support in a single shell application and the use of canopy tubes to provide support ahead of the tunnel face.The active involvement of the designer during the construction phase and the flexibility of the design concept allowed changes to the support methodology to be carried out as excavation proceeded.This paper describes the design process undertaken for portal establishment and access drift to cater for the variability of the exposed ground conditions along the drift alignment.

Jan 1, 1999

Computer software has been developed to link real-time information generated by underground mine ventilation airflow monitoring sensors into a network simulation program to undertake network simulations and allow interpretation of key system data and operational changes. Results were used in the development of a computerised monitoring and simulation system to provide immediate or real-time data on air behaviour within each branch of an underground mine ventilation network through linking of sensors to the ventilation network simulation software. The outcome of the project is an online system that can report changes in the mine ventilation system, allow causes of changes to be isolated and rectified, improve balancing of available air throughout the mine, allow improved approaches to regulator setting and dispense with much of the labour used for underground ventilation measurement. The work activities in both coal and metalliferous Australian mines have involved examination and modelling of regulators, software modification and considerable mine site testing and optimising activities. There is some discussion on approaches to control of flow through ventilation systems with increased information. New systems will be part of a total mine information management system. They will have to be cost effective and justified by gains in productivity. New systems will need to provide simulation of contaminant production such as diesels, vehicle heat, strata heat, radiation, blast fumes and other gases. More robust real-time ventilation simulation systems will be required. Personnel and vehicle identification and production tracking will be collected to provide integrated ventilation system monitoring and control. This paper examines a study to gain greater understanding of computerised real-time airflow monitoring and control within the mine production system to provide immediate simulated information in each branch of an underground ventilation network and to allow interpretation of key system data and operational changes. A case study implementing a real-time airflow monitoring and control is discussed. Approaches to control of flow through ventilation systems with increased information are discussed. The concept of a system that can be linked to or be part of a total mine information management system is developed. Such a system can form the base for mine automation that allows mines to incrementally and cost effectively implement monitoring and control to further seek gains in productivity.

Jan 1, 2005

The mining industry is facing tremendous economic challenges. Fluctuating and depressed commodity prices, the ever-increasing pressure from environmental legislation and the competing global opportunities for capital investment are placing enormous strains on every aspect of the mining business. At the same time, mines are generally becoming older and deeper with all the logistical and rock mechanics difficulties that this entails. In the face of these new challenges the industry looks to technological advances to make operations more efficient and profitable. One approach is to develop and implement highly automated and computerised equipment as part of a trend towards major reductions in the underground workforce. This approach requires more capital investment rather than less and requires a more sophisticated and well-educated workforce with skills which are generally in high demand in society as a whole. It is difficult to see how the benefit that can be gained from such technology can justify the expenditures necessary to make it operate reliably underground on a daily basis. Nor is it easy to foresee how the mining industry, based as it is often in very remote areas, will be able to hire and retain sufficient numbers of people to maintain such fleets of equipment. Another approach, and the one which I favour, is the implementation of much greater control over the whole of the mining process. Mining is essentially a very simple process - we break rock and move it. The most cost-effective means of moving and processing the mining product depends entirely on the way it is broken - it depends on primary fragmentation by blasting. I propose that the way forward for the industry in the face of our present difficulties, is not new technology but is to utilise the level of technology which currently exists in ways which have traditionally been regarded as too difficult or too inflexible - improved fragmentation and the use of conveyors. The technical success of this approach depends on the complete re-design of the ore handling system from the face or stope drawpoint to surface. The fundamental issue which determines the success of this approach is designed fragmentation.

Jan 1, 1995

By Hinchliffe WD, Griffin A

The desorption of gold from activated carbon is promoted by adding organic solvents to aqueous cyanide solutions. At 65-80¦ the elution of gold is fast and is not affected by water quality. The Micron Procedure involves pretreatment of the loaded carbon with NaCN/NaOH followed by elution with methanol vapour and condensate. Carbon is packed into a column above the distillation pot and acts as a fractionating column. Recovery of the methanol condensate leaves a methanol free concentrated gold solution and carbon containing

Jan 1, 1984

The past decade has seen a great increase in activity in deep seismic reflection profiling of the continental crust. Some 20 countries have conducted field experiments and the total length of deep seismic profiles surveyed to date is approximately 25,000 km. This total is very large compared to the quantity of such data that existed previously, but very small compared to the total length of seis- mic profiles of the shallow crust carried out for petroleum exploration, which some- times has exceeded 600,000 km on land in one year alone and 1,600,000 km/yr on land and sea. Furthermore, 25,000 km of seismic pro- filing corresponds to exploration of only a tiny fraction of the total volume of the entire continental crust. Thus at this stage of development of the subject, one must be wary of generalizations that are based on these limited data and then ex- tended in scope to include the crust everywhere. The state of the subject is such that virtually every new seismic line reveals totally unexpected seismic fea- tures, a sign that the subject is in its major discovery phase and a warning to the generalizers. Nevertheless, in addition to much new information on deep crustal structure in specific locations, some broad consequences of application of this powerful geophysical technique to a region of the earth not pre- viously explored in this manner are be- coming clear. One is that, as seismic data on the deep continental crust become more abundant and more revealing of complexi- ties, the deep crust can be far better re- lated to rocks at the surface. Conse- quently, the geological style of reason- ing is now being extended from its normal domain of the near-surface to include the deepest crust in a comprehensive story of the evolution of the continents. This change is a subtle but important one and is evident, for example, in some cross sec- tions of the North American Transect Pro- gram, which show surface geology extended in a consistent, though speculative, manner to the top of the mantle. In other words,

Jan 1, 1987