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By Rautio V

The mining sector has been automated and robotised very rapidly during the last few decades. The organisation of work, schedules and housing has been modernised from the traditional modes of industrial society toward the more flexible modes of

Jan 1, 1998

By Fabjanczyk M. W

Artificial ground support has developed into a refined science over the past 20 years. From reactive support systems such as timber props and steel supports, to active systems such as roof bolts and cable anchors, ground support technology has now developed efficient systems that work well in many instances. However this paper demonstrates that there is still a long way to go to develop optimum ground support systems. Some conventional rock bolts and cable anchors emphasise their tensile capacity only, without considering other factors such as their shear strength or shear modulus, or if the support member can transfer all of its support capacity to the surrounding rock. Examples are given of the use of ground anchors with high tensile and shear capacity in underground coal mining as well as examples of slope failures in open pits where the cable bolts have remained intact because they have been unable to transfer their full capacity to the surrounding weak rock mass. For underground coal mines, speed of installation is also of primary concern, but it must also have high tensile and shear capacity both in terms of strength and stiffness. Ground support systems of the future must therefore address these problems. An innovative new rock bolt is discussed which goes some way towards solving these problems. This new rock bolt is screwed into the rock and thus has a direct mechanical interlock with the rock. Initial field results show that it has an extremely high anchor capacity and can be fully installed in approximately 30 seconds. It has considerable capacity to improve the productivity of the coal mining industry.

Jan 1, 1992

It is well documented that drill and blast outcomes affect the downstream mining processes of loading, hauling, crushing and grinding but it can also significantly impact on mine profitability via dilution, recovery percentage, lump generation (iron ore), fines generation (coal, iron ore), coal loss and final wall stability. Drill and blast must therefore be optimised to improve the overall profitability via positively impacting on productivity and saleable product generation. It is however, difficult to achieve this because of the complexity of the number of parameters that must be integrated and managed across the entire mine value chain, ie the concept of æMine to MillÆ. This paper highlights, via a simple case study, the need to have a mineÆs drill and blast system both in control (so that it is predictable to a high degree) and with minimal variability (so the design actually makes it into the field). This type of management control is essential prior to optimisation work being undertaken. The æTeam ApproachÆ is discussed to illustrate the methodology of achieving drill and blast optimisation. A case study is presented to illustrate the potential benefits of this approach which in this mine represented a 27 per cent reduction in powder factor with the downstream functions achieving higher productivity with the same or reduced maintenance costs. It is essential for Australian mineÆs to implement the appropriate management strategies and experienced personnel placement to ensure that their mineÆs drill and blast system is correctly managed to facilitate the optimisation of profit. Without this, the Australian mining sector will become increasingly uncompetitive.

Jan 1, 1999

By Davies B, Rogers A, Grainger A, Todd J, Brenman R, Jones L, Horton B, Eager L

Research into the control of diesel particulates (DP) has been. conducted by BHP Coal for more than 7 years. Personal monitoring of employee exposures (n = 480 full shift samples) conducted at nine underground coal mines has indicated that the exposure of the workforce ranges from less than 0.1 to 2.2 mg/m3 of DP dependent on job type and mining operation. Approximately 50% of the mass of DP captured is elemental carbon (EC) which is the species currently being considered by some international regulatory authorities as the exposure standard. Five technologies for controlling DP were investigated in a combination of studies conducted in an above ground simulated tunnel, in a special controlled section of underground mine roadway and validated by application in standard coal mining operations at Tower Colliery. Tests conducted under controlled conditions indicate that dependent on the type of fuel in use, the introduction of low sulphur fuels can reduce DP levels in return airways by up to 50% and in actual mining situations a reduction of 20% can be achieved in exposure of the workforce. In addition, subjective responses from the workforce indicate that exhaust emissions from low sulphur fuels provide lower irritation and a more pleasant aroma. The use of water filled scrubber tanks reduces the level of DP emissions by 25%. Chemical decoking of engines resulted in a reduction of 20% in DP in return airways. A commercially available non-flammable disposable dry exhaust filter constructed from synthetic organic fibres with an operational lifetime in excess of 20 hours was found to reduce DP exhaust emissions by 80%. Investigations have indicated that the use of increased ventilation to control DP levels particularly in multiple vehicle situations does not follow a simple dilution factor and in some instances compliance with current regulatory requirements may not produce the required reduced exposure levels. The results from single component control strategies provide considerable reduction in exposure to DP, however the most efficient and cost effective control methodology is the use of a combination of individual systems modelled to operations conducted at each mine.

Jan 1, 1998

This paper comprises a discussion of standards for comparing conditions in mines, of methods for measuring the flow of air, of a comparison of fan performances, and the application of these matters to mines in Western Australia.UNDERGROUND CONDITIONSIn approaching the question of mine ventilation one naturally searches for some standard by which to measure the conditions in a mine.There are several clauses in the Mines Regulation Act defining the conditions which are permitted. The quantity of CO2 is limited to 0·25 by volume, but the estimation of CO2 involves a chemical determination and is not suited for general use in a mine.The maximum temperature is fixed at 87 0 F. (dry bulb), and at 80° (wet bulb). The reading of temperature is easily done in the working places, and this is a very valuable and practical test of the conditions in a mine.The wet bulb temperature is probably the most important factor in determining working conditions. It is obvious that human life cannot be sustained for any appreciable period if the wet bulb temperature is above blood heat (about 97°F.). In places where the wet bulb temperature is 90°F. there is danger of heat stroke.In places where the air in a mine is still, the wet bulb temperature rises to a value close to the rock temperature.Adequate ventilation cools the workings by transference of heat from the rock to the air stream, and the temperature...

Jan 1, 1939

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

By J Pan, B-J Shi, X-B Li

The granulation behavior of specularite fines which possess poor ballability was studied with limonite fines as a function of nuclei particles and adhering fines. The results show that the permeability of granules deteriorated as the ratio of specularite fines increased in the mixture, and the optimal granulation moisture content also decreased. The granulation kinetics results demonstrate that the adhering load of specularite fines increases rapidly within three minutes and then levels off. With increasing specularite fines ratio, the adhering speed is accelerated but the granulation duration needs to be longer to reach adhering balance. The microstructure of granule quasi-particles indicates that the fine limonite particles act as binders to bond together the specularite particles which are dispersed in the adhering layers. This can improve the adhering strength of the granules. Hence, the granulation behaviour of specularite fines can be improved by blending them with fine limonite ores which have high adhering capabilities.CITATION:Zhu, D-Q, Li, X-B, Pan, J and Shi, B-J, 2015. Granulation behaviour of specularite fines in ferrous sinter mixtures, in Proceedings Iron Ore 2015, pp 91–96 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

This paper discusses equipment replacement strategies and specifically addresses the upgrading of technologically superseded equipment. The process of equipment replacement evaluations is reviewed, and areas have been highlighted where currently accepted practice results in a bias towards retaining existing equipment longer than otherwise justified. The Discounted Average Cost Method is described and the advantages of the technique for this style of decision making discussed. Several key issues influencing the replacement evaluation are also presented together with examples from recent consulting work.

Jan 1, 1992

By Thomson S, Eisenstein Z

Field instrumentation was installed to monitor ground and lining behaviour during and after construction of the Mount Shaughnessy Tunnel (Rogers Pass Short Tunnel) in Canada. The instrumentation was placed in a soft ground section of the tunnel at its crossing with the Trans Canada Highway. The tunnel was excavated through a dense bouldery soil. Presentation of the field data and inter- pretation of the tunnel performance from a geological-geotechnical point of view form the basis of this paper. The loss of ground due to the tunnel excavation was found to be exceptionally small. This has been attributed to the unusually high strength and stiffness of the host soil. Evaluation using the Boundary Element Method, together with a simplified analytical technique, were applied to assess the relevant soil parameters and their influence on the tunnel performance.

Jan 1, 1987

Managers are demanding efficient use of their resources and part of this demand is leading to the idea of integrated audits for Occupational Health and Safety (OH&S), quality and the environment. It is possible to construct audits which test the compliance in this area with standards established by management systems and it may be that such an integrated audit of a site could reduce the time of auditing and be equally effective as three separate audits. However, this is only a maybe. To do an audit on all three aspects when they are not fully integrated results in more time wastage than doing three separate audits. But organisations are not structured around the audit process (some financial managers may query this statement). The organisational management systems are put in place to achieve the organisational goals - presumably in an efficient and cost-effective manner.

Jan 1, 1995

In 1969, Queensland Mines Limited obtained two large Prospecting Authorities in Arnhem Land, Northern Territory, Australia. The Nabarlek uranium deposit containing some 12 000 t of U308 was discovered on one of these in June 1970. Mining and stockpiling of this deposit were completed in 1979 and processing to yellowcake, which commenced in June 1980, is expected to occupy an 8-10 year period. The continuation of exploration, essential for the company to become a longer- term producer, was inhibited in 1972 by a Federal Government "freeze" on exploration in Aboriginal Reserves in the Northern Territory. Subsequently, the procedure for explorers to gain access to exploration areas in Aboriginal land was radically changed by the proclamation of the Aboriginal Land Rights (Northern Territory) Act 1976. As a result of this Act and the associated administrative policies adopted by Governments, Queensland Mines Limited has not yet regained access to the exploration areas it formally held in the early 1970's.

Jan 1, 1986

The Central Extended Orebody is located within the Cracow Goldfield approximately 360 km northwest of Brisbane and approximately 220 km west of Bundaberg. It is an epithermal gold deposit hosted by the Late Carboniferous to Early Permian Camboon Andesite. The lode was mined by open cut methods and produced 170 458 tonnes of ore at 5.62 g/t gold.The geology of the rit is relatively simple, comprising two rock types, trachyandesite and rhyolite which have been sub-divided into several units. The trachyandesite is sub-divided into three rock types: brecciated trachyandesite which is the most widespread, hydraulically fractured trachyandesite hosts the mineralisation and the third sub-unit is chloritised hydraulically fractured trachyandesite and has no associated mineralisation. The mineralisation is confined to quartz veins in hydraulically fractured trachyandesite. Several phases of brecciation and subsequent quartz and quartz/adularia vein injection are evident although not all phases are mineralised. Two rhyolite dykes intrude the trachyandesite one is monolithic, the other is sub-divided into hydraulically fractured rhyolite (barren), silicified rhyolite and auto-brecciated rhyolite.

Jan 1, 1993

Quite apart from economic considerations, the following performance parameters must be considered when selecting an explosive for a particular blasting operation. 1. total energy yield/kg, and more particularly, strain energy/kg and bubble energy/kg of charge 2. charge weight/m of blasthole 3. sensitivity of the charge 4. water resistance of the charge The effective division of an explosive's total energy into strain energy (SE) and bubble energy (BE) is explained as is the influence of each energy component on blast results. Because some rocks require a high strain energy for effective breakage, while others are most satisfactorily fragmented by bubble energy, values of SE and BE are more meaningful than those of total energy. Unfortunately, our extensive knowledge of the effects of certain variables on total energy has not yet been completely supplanted by the influence of these variables on SE and BE values. Relative SE/kg and BE/kg values are presented for a range of explosives. The 'charge density of ammonium nitrate/ fuel oil (ANFO)-type explosives is essentially constant throughout the length of the charge; because of their compressibility, slurry

Jan 1, 1974

Underlain by and intruded into the sedimentary rocks of the Transvaal Supergroup the Bushveld Complex is the largest known layered intrusion in the world and contains one of the richest ore deposits on earth. It has been the world's major source of Platinum Group Metals (PGM) since the mid-1900s with Chromite and PGMs the two most economically important components of the Bushveld Complex. The lower group (LG), within the critical zone, consists of seven chromitite layers and it is within this sequence of chromitite layers, the most important target of the lower chromitite group is found, ie the LG6 chromitite unit. The LG6 chromitite unit consists of a chromitite duplex composed of the lower LG6 chromitite layer (Steelport seam), averaging 1 m thick, overlain by a 0.66 m waste parting and a thin 0.34 m thick LG6a chromitite layer (leader layer).Two mining methods are commonly applied in the Bushveld Complex to extract the LG6 chromitite layer package. One method consists of footwall development utilising rail bound equipment to gain access to the orebody and then extracts only the LG6 chromitite layer by means of hand held rock drills and scraper winches. The second method is the use of mechanised equipment to access the orebody on the plane of the ore utilising bord and pillar mining method, which extracts the full mineral resource, ie the LG6 and LG6a layers. Conventional narrow vein stoping is often selected due to the large conventional mining skills base found in South Africa, the perceived cost and dilution implications of utilising mechanised equipment, and the difficulties of using mechanised equipment at dips above 12¦. The driving factor for mechanised mining is the perceived ability to access the orebody quickly and inexpensively, and extract the entire mineral resource package (LG6 and LG6a) while limiting capital expenditure and improving safety.This paper investigates these two commonly applied approaches, highlighting the benefits and problems associated with the two approaches. Comparisons will be made of the two mining methods and recommendations given for the mining engineer to consider before selecting the appropriate mine design.

Dec 6, 2010

By Sulanto J, Talonen T

In the mid 1960's Outokumpu considered building a lead Flash Smelter on the basis of Flash Smelting technology developed first in the late 1940s for smelting copper concentrates. Pilot scale tests were carried out and the process was found technically sound. The project was however not economically viable under Finnish conditions and it was cancelled. In 1981 pilot plant tests were restarted after many enquiries from the primary lead producers. All the know-how and development made in copper and nickel smelters was applied to the Lead Flash Smelting process and the tests were successful. Outokumpu has so far tested several types of lead concentrate with lead contents ranging from 28 to 75 per cent. The concentrate is oxidized and smelted to metallic lead and slag directly in the Flash Smelting Furnace using high oxygen enrichment of tonnage oxygen. Fossile fuel is used in the Flash Smelting Furnace in cases when the feed material does not contain enough latent heat to smelt the furnace products even though pure oxygen is used for oxidation. Thus the process results in a low consumption of extraneous energy. Use of oxygen results in a small gas flow but it is rich in sulphur dioxide. The gas treatment facilities and sulphur recovery plant will be small in size and low in investment cost. The process is flexible and can produce stable quality of products from different types of raw materials. Quality of lead bullion especially the sulphur content can be regulated over wide a range, from 0.1 per cent upwards according to the needs of the refinery.

Jan 1, 1984

By W Boughton, L Gilbert

The Australian Water Balance Model (AWBM) has found widespread use in Australia in estimating the streamflow behaviour of catchments. It has been used at the Ridgeway Gold Mine, in central west New South Wales, to estimate streamflows in creeks potentially affected by loss of spring-fed baseflow due to mine dewatering. The AWBM estimates are used to assess the effect of mining on streamflows and the need to provide compensatory flow releases, which would be drawn from mine water supplies, into the creeks, in compliance with regulatory consent requirements. The monitored flows in some of the creeks exhibit non-typical behaviour, with streamflows increasing in autumn months despite a lack of significant rainfall. This behaviour is believed to be due to the combined effects of discharge from rock fractures and the effects of evapotranspiration in the riparian zone. A modified version of the AWBM has been developed which much more closely simulates the observed flow behaviour and which will be used in ongoing flow assessments for the mine. This paper outlines the difficulties involved in modelling low flows in small catchments that are subject to a number of influences (other than mining), describes the development of a refined model to improve simulation of low flows and baseflow in small headwater catchments and highlights the need for good baseline data to calibrate such models.

Jan 1, 2006

By Bearman R. A, Parkin R. M

Traditional quality control procedures for aggregates production within the quarry industry rely on off-line laboratory analysis, resulting in poor performance and inconsistent product quality. A high speed on-line aggregate classification system is described here. A product sampling system directs aggregate through an inspection chamber where a novel imaging system digitises the particle geometry. Data processing algorithms extract dimensional data and image features, while a neural network classifier assigns a qualitative shape descriptor to each rock particle. This system provides each sampled batch with a complete analysis of size and shape distributions, complementing a new generation of cone crusher technology to maximise product quality and plant efficiency.

Jan 1, 1995

By R J. Higgins, M Edraki

What is the meaning of the Life of a Mine (LOM) if that mine results in a requirement for water treatment in perpetuity? ‘In perpetuity’ is of course a duration with no relationship to a Life-of-Mine or what might rightly be regarded by external stakeholders as a fair and reasonable post-mine recovery period. It exceeds the life span of investors, mine managers and governments, indeed even of capital markets as we know them, and of corporate and individual memories.In mine and mine closure planning, decisions are usually based at least to a significant extent on traditional economic analysis underlain by discounted cash flows (DCF). For investments in income-producing facilities, such as mining development and equipment, and ore-processing plant and equipment, this analysis reflects commercial reality and allows for comparison of competing investments. However, for environmental and social infrastructure, the same analysis using the same input parameters, especially the discount rate applied to cash flows, can lead to a bias against the adoption of best practices for non-investor stakeholders. CITATION:Higgins, R J and Edraki, M, 2018. Water treatment in perpetuity – or not?, in Proceedings Life-of-Mine 2018, pp 131–132 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By Merwin RA

The recent development of rare earth permanent magnets has revolutionised the field of magnetic separation. The advent of rare earth permanent magnets in the 1980s provided a magnetic energy product an order of magnitude greater than that of conventional ferrite magnets. This has allowed the design of high-intensity magnetic circuits operating energy free and surpassing the strength and effectiveness of electromagnets. New applications and design concepts focusing on the mineral and metal processing industries have evolved. This technology also led to the development of various magnetic separators specifically designed for mineral processing applications. Applications which were not previously considered are now being applied to primary mineral upgrading and recycling and secondary recovery.

Jan 1, 1993

By Sobek S, Lotzien RM

Although the conventional procedures for designing agitator flotation plants are well-known and reliable, little experience for designing modem pneumatic flotation plants has been gained up to now. A reliable procedure originating from graphic methods for the design of distillation columns is presented. Examples demonstrate on laboratory and semi-technical scale the application of this extremely practical method for designing a fly ash and a magnesite flotation plant.

Jan 1, 1993