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By Dobias B

A new separation method based on a combination of coagulation and colum flotation was used to treat fine sphalerite in the range 90 per cent - 15 pm with a relative high superfical gas velocity and a thick froth layer. Minerals studied include sphalerite, calcite, kaolinite and baryte. A new developed sedimentometer was used for sedimentation analysis to characterise hetercoagulation of mixture and coagulation after addition of active ions or reagents. A comparison between use of selective frother and depressant (SHMP) was made to deactivate activated minerals. Selectivity of frother for sphalerite was found in flotation test. The depression function of Flotanol for activated minerals was confirmed in sedimentation alalysis. The use of small quantities of HPAM can improve the flotation of fine sized sphalerite particle and reduce recovery of activated gangue minerals in the neutral or alkaline pulp. A satisfactory separation of fine sphalerite from its gangue was achieved by using alkylpolyglycolether (Flotanol) and copolymer polyacrylamide (HPAM hydrolysed polyacrylamide) as frothing and flocculating agents Respectively.

Jan 1, 1993

Most mining dredges are adapted from canal/harbour dredges. Their automation and control systems are generally not designed for integrated mining operations. Consequently they have a number of limitations. This paper describes a new dredge control concept which paves the way for improved efficiency and increased production.

Jan 1, 2001

By M Byrne, P Newman, M Lindqvist

SomincorÆs Neves Corvo Mine, one of the largest copper producers in Europe, is currently constructing a paste backfill plant in order to replace cemented rockfill in its bench and fill stopes and possibly replace hydraulic sandfill in the drift and fill stopes. A 250 m flow loop was constructed at the mine and the flow properties of various paste blends were investigated. Cycloned tailings and total tailings were both pumped successfully as pastes and were also combined with waste rock for additional testing. The pressure losses in 102 mm and 154 mm diameter pipeline were recorded at flowrates up to 60 m3/hr and are presented at slumps from 120 mm to 250 mm. The data showed the sensitivity of paste mixtures to slight changes in consistency, confirming the need for accurate control during paste production and distribution. The flow results clearly showed the different paste behaviour between cycloned and total tailings pastes and the change in properties at low and high slumps. In addition to pressure loss data, strength testing was done on 38 mm and 82 mm diameter samples. Further strength testing is ongoing at the mine using fly ash as a supplement to cement, reducing the overall binder cost. Preliminary engineering for the underground distribution system is briefly discussed, with reference to the siting of the plant. The Neves Corvo Mine is particularly shallow and alternative methods to pumping were sought in order to ensure sufficient hydraulic head for underground distribution. The comparison of options had to take into account the capital and operating costs, the operation of the plant and the impact on the future expansion of paste fill utilisation at Neves Corvo.

Jan 1, 1998

By M Alston

Many organisations struggle to yield meaningful outcomes from incident investigations. This paper will demonstrate that we can discover systemic issues by rethinking the ‘Why’ and ‘How’ of investigations, fostering genuine risk reduction. Key points: 1. Shift from ‘prevent recurrence’ to ‘learn and reduce risk’: conventional investigations focus narrowly on recurrence prevention, resulting in narrowly focused investigations with limited ability to identify and reduce organisational risk. Redirecting our objective to learning and improvement opens avenues for broader risk mitigation. 2. Understanding daily work for risk insights: recognise that work is not always completed in full compliance with procedures. Workers will adapt how they complete tasks influenced by the conditions and management systems that exist every day. Understanding the conditions and systems affecting everyday work is vital for uncovering systemic risks. 3. Unearth systemic issues through in-depth exploration: many investigations address surface concerns such as lack of training, incorrect procedures, equipment not being maintained, and missing overarching organisational risks. Systemic, organisation-wide risks are not identified. To discover these systemic issues and create shared learnings, investigators must question management systems, including resourcing, planning and risk management. 4. Design actions for safe failure: common actions like discipline and training fall short and do not reduce risk. Resilience emerges from well-designed controls. Incorporate planning, better resources, interlocks, and guarding to bridge the gap between task execution and risk. 5. Investigation Reports as a Business Case: Investigation reports should not simply state historical information regarding an incident. They are to facilitate decision-making and be presented as a business case to drive change. Organisations can move beyond localised risk and ineffective administrative actions by changing investigation objectives and methods. They can facilitate learning, understand daily work intricacies, identify systemic issues, and enhance the capacity for safety, driving lasting risk reduction.

Apr 16, 2024

By S Pollak, A Amon

This paper describes the current and finished design work which has been performed for shallow rock station caverns for New York CityÆs first new subway construction in 60 years. A new robust, sophisticated, design procedure has been developed for two up to 30 m wide caverns, with overburden of less then 12 m, and rock cover to span ratios (C/S) in the order of 0.25. The design is based on empirical input parameters like the Q-value, rock mass rating (RMR) values, rock mass class after Cording (1984), cover to span ratios, which have been validated by the use of structural computer models as well as two- and three-dimensional numerical discontinuum models. The design approach is a staged approach using first principles, empirical models and non-linear FEM and DEM models. In addition, the paper describes the factors and circumstances why shallow caverns have been selected instead of cut-and-cover structures and why all the underground station structures have been developed as drained structures.

Jan 1, 2008

By Corrans I. J

A wide variety of copper-bearing gold ores exist throughout the world which have yet to be processed economically for gold recovery. The copper minerals present in these ores can be many and varied and usually result in high cyanide consumptions and problematical levels of copper in leach solutions. The copper content is often assessed as being of nuisance value as the ores are generally of the grade or type which can support neither a copper project nor a straight gold project, due to the interference of copper. Many of these problematical gold-copper ores could possibly be processed economically for gold recovery using a novel ammoniacal cyanide leaching system which utilises a copper-ammonia-cyanide complex as an effective lixiviant for gold, yet limits copper dissolution and conserves cyanide. Results from recent testing have promoted a re-evaluation of the economics of treating some gold-copper ores. This paper describes the novel leaching process and discusses the conditions employed to treat a variety of gold-copper ores.

Jan 1, 1992

The automatic control of grinding mills for optimum performance is an area of control which can benefit from new control concepts and technology. Economic pressures dictate that the mining industry undertake changes in process design, control system strategy and operations organisation that call for innovative reappraisals of the control system performance necessary to enhance the functions of the process operator. As more dependence is placed on instrumentation the chances of abrupt, total loss of process control through an entire production complex becomes a major concern of the plant manager.

Jan 1, 1978

Coal exports are forecast to grow strongly, so that coal is likely to remain very important to Australia for the foreseeable future. However there is no sign that prices or profitability will rise of their own accord. Therefore the intense squeeze on costs will continue for the foreseeable future. This will mean lower manning, more outsourcing and probably an increasing rate of company attrition. As well, the political pressure from the greenhouse debate is only going to intensify and the pressure on the Federal Government after Kyoto is likely to be irresistible.

Jan 1, 1998

By James S. E

Financial risk of environmental problems is the key to many important business decisions within the mining industry. Massive uncertainty makes it difficult to choose a strategy for managing environmental problems to reduce corporate financial exposure to environmental impairment. A correct and practical method exists to clarify the risks and help make decisions. A case study on an insurance problem illustrates the method.The approach used is to translate existing data on environmental problems into probabilistic expressions of financial risk, and organise the expressions to reveal alternative solution strategies for the insurance problem.

Jan 1, 1993

Probably no other country or coutinent has so many rich deposits of various different minerals as Australia. Long ago in the days of my boyhood in the old land the marvellous discoveries of high percentage copper at Burra Burra, Peak Downs, Yudanamutana, and other mines, was one of the principal themes of conversation in mining circles whilst the specimens of malachite, azurite, etc, brought home by returning miners were the admiration of my boyish eyes.Later on the WalIaroo and Moonta mines still further helped to heighten the reputation of Australia as a copper-producing country. During the 21 years that the writer has been resident in the Australian colonies, other mineral deposits have sprung into prominence, and with a Mount Bischoff for tin, a Broken Hill for silver and lead, and a Mount Morgan for gold, Australia can now boast that it has had within its borders the leading mines of the world, in four different minerals, and still at least maintains that pre-eminence in gold, silver and tin. To the miner from the old land, Australian mining is at first a revelation and a wonder. In very many instances he looks in vain for the regular strike and dip of the veins he has been accustomed to'Smooth hanging and foot alls are often wanting. 'Huge irregular deposits, like those mentioned above, viz., Burra Burra, Mount Bischoff, Broken Hill, and Mount Morgan, are mysteries that will take time to fathom-if, indeed, they are ever thoroughly understood and in many a smaller deposit there is much to interest alike the professor in the college and the miner in the mine.

By K M. Watling, F M, G K. Parker

Surface enhanced Raman scattering (SERS) spectroscopy at surfaces under electrochemical control has been applied to elucidate the adsorption of thiol collectors. SERS spectroelectrochemical studies at coinage metal electrodes have been carried out on ethyl xanthate and three iso-xanthates, O-isopropyl-N-ethylthionocarbamate, 2-mercaptobenzothiazole, diisobutyl- dithiophosphinate and butylethoxycarbonylthioura. For each collector, adsorption occurs via charge transfer to form a metal-sulfur bond and, in situations for which the reversible potential of the formation of the bulk phase is known, at underpotentials.

Jan 1, 2005

By D La Rosa, A Jankovi, A Dance, W Valery

This paper presents the methodology for optimising blasting and comminution processes in terms of fragmentation developed by Metso Minerals Process Technology Asia-Pacific and South America (MMPT). The methodology is called process integration and optimisation (PIO) and involves a number of steps: benchmarking, rock characterisation, measurements, modelling/simulation of blasting and comminution processes and where required, material tracking. The measurements collected while at site are combined with rock characterisation and definition of ore domains to model the complete process chain. These data are used to develop site-specific models of blast fragmentation, crushing, grinding and flotation. This allows customised blast patterns to be developed that optimise both crushing and grinding performance. For each domain, blast designs are recommended to generate the optimal fragmentation size for downstream processes. The objective is to minimise the overall cost for the entire process and the changes often have a positive impact on the mining operation. Process constraints such as wall stability, ore dilution, muck pile characteristics, size of mining equipment, size and installed power of crushing and milling equipment and other process bottlenecks are considered in the blast designs. This methodology has allowed many operations around the world to significantly increase their production: generating typically five to 20 per cent higher concentrator throughput. A number of case studies will be discussed in this paper to describe the structured approach taken and demonstrate the benefits that are achievable. This paper will focus on the role of blasting in the optimisation of the entire mine to mill process chain and discuss elements of the PIO methodology: rock characterisation, fragmentation modelling and measurement, the relationship between fragmentation and mill throughput and material tracking.

Jan 1, 2007

By P Gnnther, A M. van Niekerk

Coal mining operations in the Upper Olifants River Catchment in the Mpumalanga Province of South Africa are challenged with the increasing production of excess mine water that cannot be fully managed by existing practices of pollution control at source, recycling, and reuse on mining sites, storage and limited release to the natural water course. In contrast to this, the Olifants River Catchment is experiencing water stress and insufficient water is available to satisfy all water quantity and quality requirements for future industrial and municipal growth. It is estimated that the catchment has a deficit of 192 million m3 per annum if the reserve water requirements are taken into account. The future increased water requirements can be met by water transferred to the Olifants River Catchment from adjacent catchments. The cost of transferred water is likely to be substantially higher than the current cost of water supplied to local municipalities, commerce and industry. BHP Billiton and Anglo Coal Corporation are working together to jointly implement water management strategies that will contribute to the achievement of in-stream and dam water quality and aquatic objectives for the catchment. Consideration is now being given to the treatment and beneficial use of excess mine water. This will inaugurate a new era for the coal mining industry in South Africa, in which a pollution threat to the water resources in the Upper Olifants River Catchment is converted into a water source for beneficial use. Three potential mine water reclamation and reuse schemes have been identified and this paper details the technical, institutional, legal and financial considerations in the implementation of these schemes.

Jan 1, 2006

Welcome to Mount Isa- my home city and without doubtthe base for what promises to be the most exciting mineral development yet seen in Australia.Mr. Chairman, it also gives me great pride to representthis area in the Queensland State Parliament as well as being the Minister for Minerals and Energy in the Queensland Government.Mount Isa is now part of the Australian mining industry folklore.It is all what a good mine is all about. It is. all what a good community is all about.

Jan 1, 1993

By Crosby N. R

The design of mine openings and the assessment of their reserve are processes ihicl, require the routine manipulation of considerable amounts of data. A number of computer programs have been assembled to operate in a mini computer in order to provide some mechanical assistance for these processes. The system responds to plain language commands. which allows mining engineers to compute the reserves for a number of possible mining outlines, on an interactive basis. Methods of numerical analysis were used in preference to statistical or qeostatistical techniques.

Jan 1, 1977

By Hood M

Rock cutting excavation technologies and particularly continuous excavation technologies, can offer benefits in the areas of reduced costs, higher revenue and increased safety in a variety of mining situations. Non-explosive rock excavation technologies for example, can deliver significant benefits in the areas of dilution and improved ground support (no overbreak). This paper is an attempt to focus on the development and future of alternative rock breaking technologies and to provide some insights as to why and how we should proceed in this direction. The market size for underground hard rock excavation technologies is examined. A short review of the evolution of various rock excavation technologies in terms of cost and production rate is given and a summary of the state-of-the-art technology is presented. Mechanical excavation technologies (TBM) have very high production rates compared to D&B and the gap is widening, however, they have not been successfully applied to mining applications. Operating costs for mechanical and D&B systems have been dropping over time, however, D&B costs are the lowest. Given the current state of knowledge it appears that with regard to hard rock underground metalliferous mining that R&D efforts should be focussed in the following areas - disc cutter tool development (materials and design; operation; presentation to the rock surface), hybrid cutting systems (consisting of water jets and disc cutters) and development of pressurised hole breakage technologies. It is also possible that two techniques known as the pulsed laser and pulsed water jets may have some potential. The generally agreed specifications for a widely applicable underground hard rock excavating machine are - disc cutter based, a minimum production rate of 100 t/h, be flexible, manoeuvrable and deployable, weight of less than 100 tonnes and be economically competitive with D&B in rocks over 150 MPa UCS. Such a machine would seriously challenge the position of conventional D&B in a wide range applications and provide some of the benefits of mechanisation and automation that the mining industry is pushing so hard for. However, technology developments in the D&B area are not static and hence the target is moving and is increasingly difficult to overtake.

Jan 1, 1995

By R Dunne, G Lane, S Ha, D Dreisinger

The paper outlines the 17 Mt/a Telfer Project plant process design from sample selection to feasibility study design. The 366 Mt Telfer mine reserve consists of a diverse range of copper and gold mineralisation, from massive sulfide reef ores to stockwork ore, oxide copper minerals to chalcopyrite, siltstone to competent quartzite, all with relatively high levels of gravity recoverable gold. The complexity of the orebody demanded a flexible plant that could recover copper and gold values by a combination of gravity recovery, flotation and concentrate leaching. The demands of treating ore from a high grade underground mine and a variable grade open pit (that includes underground old mine workings) necessitated a dual train approach from primary crushing to concentrate production in order to minimise the requirement for campaigning of different ore types. An extensive sampling, testwork and technical evaluation program was undertaken to identify processing characteristics and the optimum process route for each ore type. The design experience included: the development of robust primary stockpiling and pebble crushing concepts; detailed review of scale-up of SAG and ball mill pilot plant data to plant scale; the selection of two 15 MW SAG mills and two 13 MW ball mills for the grinding circuit; and detailed modelling of the pyrite concentrate carbon-in-leach (CIL)/sulfidisation acidification recovery thickening (SART)/acidification volatilisation recovery (AVR) process to optimise design for copper and cyanide recovery from leach liquors. The Telfer plant design also measures the development of process design based on experiences at the Cadia Hill Cu/Au concentrator, commissioned in 1998. The differences between the two plants are compared and contrasted.

Jan 1, 2003

Gold mine production in South America was 247.3 tonnes in 1995 up from 156.4 tonnes ten years earlier in 1986. This represents a 58 per cent increase and amounted to 11 per cent of total world gold mine production. The major countries involved in order of production, were: Brazil (67.4 tonnes), Peru (51.5 tonnes),. Chile (48.5 tonnes), Colombia (24.1 tonnes), Venezuela (17.1 tonnes), Bolivia (16.0 tonnes), Ecuador (9.6 tonnes), Guyana (8.8 tonnes), French Guiana (3.3 tonnes) and Argentina (one tonne). The most dramatic increase was reported in Peru where production increased from 10.9 tonnes in 1986 to 51.5 tonnes in 1995, heavily influenced by the production from Minera Yanacocha which began operations in 1993 and produced 17.2 tonnes in 1995.With the reformation of the mining laws and the introduction of investment incentives in all the South American countries in recent years, dozens of major and junior mining companies began flocking into the area in the early-1990s to conduct exploration. A recent study undertaken in Brazil shows that an average of $240 million per year will be expended in this country during the period 1993 - 2010. Twenty-five per cent of this expenditure is expected to be made on gold exploration. Similar figures for Peru are $220 million total per year with 50 per cent for gold; $170 million per year in Argentina with 25 per cent for gold and $120 million ner year in Chile also with 25 Der cent for gold.

Jan 1, 1997

By Susanto A

As part of the current NERDDC funded project studying Dragline/Hopper/ Crusher/Conveyor systems for overburden removal, an investigation was carried out to assess the feasibility of automating the swing-to-dump phase of the dragline digging cycle in order to main- tain consistent performance of spotting the bucket above the hopper prior to dumping. The study involved design of automatic position controls for the hoist, drag and swing drives and simulation of detailed mathe- matical models of the three electromechanical systems and their associated electrical control schemes. The design of the hoist and drag systems to position the bucket in the boom plane is relatively straightforward. Simulation results show fast and accurate performance, with no evidence of interaction between the two drive systems through the ropes. The design of the swing position control system involves special strate- gies to cater for variable inertia and to damp the pendulum oscillations of the bucket. The use of a bucket pendulum model and variable dynamic compensation embedded within the feedback control loop, along with optimal speed/angle slowdown trajectories, has yielded fast and damped positioning responses under simulation.

Jan 1, 1989

A key premise to this paper is that most people involved in the design and implementation of drilling and blasting operations could benefit from a greater understanding of the geological materials, deposits and landforms they are dealing with. The second key ingredient for successful blasting is the concept of blasting objective. Mine operators and blasting contractors must be clear on what drives their costs (blasting leverage) and should formulate blasting objectives and operational targets which help in this regard. Many operators ignore geology descriptors and features apart from the name of the rock and start crudely quantifying the rock mass properties in terms of uniaxial compressive strength, or even worse still as hard or soft. This occurs too early in the design process and not much attention is paid to the geological materials, geological structures and the characteristics of the deposit they intend to excavate. In effect the rock type name and the strength descriptor become the site geology. Furthermore many blasting operators do not formalise their blasting objective, do not set operational targets and do not measure results to the degree required for continuous improvement. In this paper a number of civil, surface mine and underground mine blasting applications are tabulated in terms of typical blasting objectives and common geological materials. A good description of geological materials can convey a lot of useful information for blasting operators if they are able to accommodate this knowledge. In addition a clear statement of the blasting objective and associated operational targets will maximise the likelihood of achieving blast-driven downstream productivity improvements. The æStarting at Both EndsÆ combination is deemed extremely useful for any continuous improvement blasting program.

Jan 1, 1999