Search Documents

This paper is for mine managers. It is about maintenance of mining equipment. This is an extremely broad subject so this paper is given with the caveat that it necessarily contains generalisations, not true in all cases, but broadly correct. The job of mine managers is to be good at making money from the excavation and preliminary treatment of mineral. To do this well, they need to understand the cost and value drivers in the business. This includes understanding the drivers associated with maintenance. Maintenance is often identified as a problem at mine sites. It is frequently listed as the cause of production shortfalls when reporting. The state of maintenance within mining as an industry is generally among the lower end of the range, when compared to manufacturing, petrochemicals, etc. Why is this? Experience and review of many audits and evaluations of maintenance has shown that some patterns are consistent with good performance and some consistent with poor performance. These often centre around the time horizon of the management team and are associated with knowing the sensitivity of the business to certain maintenance drivers and the mechanisms of maintenance and their results. To summarise, some common misunderstandings can be listed as statements that are obvious and extrapolations from those, which are not necessarily correct. For example: High availability of equipment is necessary for production. Incorrect extrapolation:focus on availability will produce high production. Design is often the greatest factor in determining the reliability of a mining machine. Incorrect extrapolation: the newest and biggest machines generally have the lowest cost operations. Operation has an enormous impact on machine productivity and reliability. Incorrect extrapolation: the fastest operators are generally the best from a productive point of view. Some maintenance improves the performance and reliability of machines. Incorrect extrapolation: more maintenance will give you more reliability. Some maintenance depends on disassembly and reassembly of components. Incorrect extrapolation: assembly is basically the reverse process of disassembly. Maintenance improvement in the mining industry in the last 15 years has focused largely on planning and systems improvement. Incorrect extrapolation: most of the problems in maintenance can be traced to a lack of planning. Actions based on flawed extrapolations will steer a business suboptimally. It is therefore important that the mine manager understands these issues so that the improvement effort can be directed to the greatest benefit.

Jan 1, 2006

By A F. Idziak

The aim of the present study was an application of coal optical property measurements for analysis of paleostress field existing in fault zones of the Upper Silesian Coal Basin (USCB) during the coalification of organic matter. Measurements of vitrinite reflectance were carried out on coal samples taken near a hanging stope of the Klodnicki fault. Other samples had been taken in vicinity of the Krzyzowicki fault. The Klodnicki fault is one of the main tectonic discontinuities in the northern part of the USCB. It is postulated that its origin is related to the deep-rooted latitudinal discontinuity in crystalline basement of the basin. The Krzyzowicki fault is located in the western part of the USCB where fold tectonic style dominates. Vitrinite, one of the basic components of hard coal is generally considered as optically anisotropic material. Anisotropy of physical properties is induced mainly by stress, which arranges vitrinite structure. Vitrinite anisotropy can be described by an ellipsoidal model called reflectance indicating surface (RIS) which is a geometrical representation of the optical anisotropy tensor. The investigation of the RIS for vitrinite was carried out on coal samples. The apparent maximum and minimum reflectance values measured for a single vitrinite particle were plotted against corresponding bireflectance to construct the reflectance crossplot. Interpretation of this plot yielded the magnitudes of the RIS three principal axes. The data obtained point to differences in optical anisotropy of coal under the study. The coal samples taken from block tectonic zone near the Klodnicki fault had mean reflectance value of less than 0.80 per cent. Their anisotropy coefficients were about 0.1. Optical properties of coal changed from the biaxial positive in the western segment of the fault to the biaxial negative in its eastern part. It suggests that past tectonic stress was greater in the western part of the zone than in the eastern one. Coal originated from a fold tectonic zone at the vicinity of the Krzyzowicki fault has mean reflectance value much greater than from previous region (ÿ1.20 per cent). Its optical anisotropy coefficient is equal to about 0.07. It suggests that paleostress field was more isotropic. The presented study shows the usefulness of coal reflectance measurements in the analysis of paleostress field existing during coalification process.

Jan 1, 2003

By P Commander

Western Australia is a major exporter of minerals, which places significant economic and environmental responsibility on Government and the stateÆs mining industry. Moving into the 21st century, mineral production in Western Australia is $14 billion accounting for 50 per cent of the stateÆs export income. There are over 60 large-scale mining operations distributed throughout the arid regions of the state (less than 300 mm/year rainfall). There are four key mineral provinces in arid Western Australia including the Pilbara (iron ore), Murchison (gold), Northern and Southern Goldfields (gold and nickel). These provinces have significant differences, particularly in respect to groundwater demand from mining and mineral processing, aquifer systems that are utilised, and approaches to groundwater management. The arid nature of the stateÆs interior and subsequent lack of surface water resources has required substantial groundwater resource development by the mining industry. A variety of aquifers have been explored and utilised ranging from shallow alluvium and calcrete, discrete fractured zones in bedrock, concealed palaeochannels and inland sedimentary basins. Groundwater usage by the mining industry is about 150 GL/year with most abstraction related to mine dewatering, mineral processing and dust suppression. Groundwater abstraction in Western Australia is regulated by the Water and Rivers Commission. In the Goldfields, the depletion of brackish (>2000 mg/L) and saline groundwater from storage is permissible, as mining is considered the beneficial use for groundwater which may be as much as 200 000 mg/L. In contrast, the low salinity groundwater of the Murchison and Pilbara is allocated on a sustainable basis. The role of monitoring and ongoing aquifer reassessment is crucial in water management, in evaluating the condition and performance of stressed aquifer systems. Mining operations face a variety of water resource issues ranging from insufficient availability for processing to excessive mine dewatering. These issues also change as a mine operation proceeds through its development, commonly starting with a deficiency and moving into surplus as deeper pits require more dewatering. Operating mines have to contend with three main issues: water supply, wastewater disposal and contamination of local water resources. In contrast, post closure issues are related to aquifer recovery or re-establishment of groundwater equilibrium, development of pit lakes in mine voids and isolation of waste products and associated seepage or run-off.

Jan 1, 2003

By B Ilich, M Brad, R Brandli, E MarT

The Wirtgen surface miner was investigated for application to the Cloud Break iron ore deposit since it can selectively mine thin seams and there is no requirement for drilling and blasting or primary crushing as the surface miner cuts and breaks the rock to secondary cone crusher feed size. A physical metallurgical study of the surface miner run-of-mine (ROM) from Cloud Break was conducted to better understand the product size distribution, amount of -31.5 +6.3 mm lump produced, lump stability and physical metallurgical quality compared to conventional drill and blast techniques. Since the Cloud Break mine was not in production, the lump product from crushing and screening of surface miner ROM was compared with product simulations using traditional premining physical metallurgical processing techniques including drop testing of PQ diamond core. Drop test conditioning is widely used in the iron ore industry to simulate blasting, crushing and screening at the mine and subsequent product degradation during handling from mine to port to predict both the amount of lump product on ship and the size distribution of the fines and lump. The size distributions of surface miner ROM for hard, medium and friable ore types show very tight size distributions with very little above 100 - 150 mm, about 60 per cent of the distribution between 75 and 6.3 mm, with less below 1 mm compared to conventional drill and blast ROM. Crushing, screening and drop test conditioning of the surface miner ROM produced more lump in equivalent ore types compared to drill and blast techniques or their breakage simulation using PQ diamond core. The higher lump yield from the surface miner was also confirmed by pilot scale crushing of some 7400 t of surface miner ROM from the Cloud Break trial pit. The lump produced from surface miner ROM was quite stable and showed similar low degradation characteristics to lump simulated from drill and blasting techniques. Product size distribution simulations using conditioned crushed lump from 1 m diameter Bauer hole samples were found to compare well with processed PQ core samples and surface miner product from trial mining at Cloud Break. The Bauer sample method is therefore considered to be a very useful close simulation to actual lump production, although the lump yield is lower.

Jan 1, 2007

The aquifer at Phosphate Hill, north-west Queensland, presents special management challenges. The site contains a phosphate rock mine, fertilizer plant and camp. All of the site water is provided by the Duchess Embayment Aquifer, located within the Burke River Outlier of the Georgina Basin. The Duchess Embayment is a triangular shaped, Cambrian marine sedimentary basin consisting of siliceous and calcareous phosphorites, shales, siltstones and sandstones. It is fault-bounded on all sides and has a regional dip of 5¦E. The aquifer is largely confined to the siliceous facies of the Beetle Creek Formation. It has a very flat potentiometric surface and an average thickness of 45 m with confining beds above and below. The siliceous facies derives from weathering of the calcareous phase and is highly transmissive while the calcareous zone itself contains less water and is dependent upon interconnecting fractures for its permeability. Recharge appears to occur where the siliceous facies crops out around the edges of, and within, the Embayment. Aquifer management issues revolve around two points: successful dewatering of the orebody for mining; and efficient management to maintain water quality and ensure supply over the predicted 30-year life of the project. Current operations are extracting water at levels much below that originally estimated. This is having a detrimental effect on mine dewatering with the SWL lowering at a rate slower than anticipated. As a result, ore parcels are now beginning to intersect the water table, providing a major constraint to the mining plan. The aquifer drawdown cone is extensive and very flat so to keep the water table at an appropriate level for mining the management plan will include more aggressive dewatering to lower the level of the entire aquifer. The additional water will either be disposed of downstream or stored in a holding dam or via the use of artificial storage and recharge. Water resource management will also need to maintain the current quality. About 37 per cent of the water currently extracted forms the low chloride supply required by the ammonia plant and the power station. This ratio is expected to remain applicable under any future operating conditions but the low chloride resource is restricted so will require prudent management to enable the supply to continue. At current usage rates aquifer recharge versus use will need careful monitoring to ensure that the resource remains viable in the long-term.

Jan 1, 2003

Gold was discovered in the Bendigo area of Victoria in 1851 (Willman and Wilkinson, 1993), and all the early gold mining of any note involved washing (puddling) the gold out of the regolith or alluvium. The waste material from this process was a semi-fluid mixture of rock debris, soil and water, referred to as `sludge'. Puddling machines were gradually introduced to speed up the puddling process (Cole, 1994), and by 1855 an estimated 2000 machines were in the district (Anderson, 1978). In 1859 it was estimated that approximately 2 293 000 m3 of material was puddled annually by the machines on the eastern side of the goldfield, whose waste drained into Bendigo Creek and its tributary gullies. It was also estimated that after the gold was removed, approximately one-quarter of the residue/sludge consisted of the heavier, coarse-grained material which settled out fairly quickly, while the remainder, approximately 1 720 000 m3, was the fine-grained material which flowed downstream for some distance (VPP, 1859 - 60). From these figures it can be assumed that for the ten years during which this volume of puddling was maintained (1854 - 1864) over 5 700 000 m3 of gravels and sands and 17 200 000 m3 of fine-grained sludge had been discharged into and around Bendigo Creek. This was enough to cover an area of over 400 km2 to a depth of 5 cm. By 1859 the problems associated with the sheer volume of sludge being discharged were such that a Royal Commission was appointed to `Enquire into the Best Method of Removing the Sludge from the Gold Fields' (VPP, 1859 - 60). The goldfields referred to were those in the Bendigo area around the township of Sandhurst (now known as Bendigo). The Report of the Commission (VPP, 1859 - 60) stated that: `... inspection of the country bordering upon the course of the Bendigo Creek, to a distance of about fifty miles from Sandhurst . . . ' had revealed that the sludge had ' . . . filled up watercourses and flooded pasture lands . . . '. It also noted that ' . . . even on the plains, thirty or forty miles away from Sandhurst, where the sludge flows thin, and is relieved from its heavier particles, we found it baked into a perfect concrete, and in thicknesses varying up to two feet or more . . . '. The italics were used for emphasis in the original text. As it was considered unlikely that the physical evidence for such widespread inundation would have disappeared completely over the intervening 130 or so years, a project was initiated to locate any evidence of the inundation in the current landscape. If such evidence were to be found, then an estimate could be made of both its extent and its effects on the topography, drainage, and land-use of the inundated area. Extensive field work has determined that over 700 km2 to the north of Bendigo was inundated by the sludge. The area has not been uniformly covered, but has occasional `inliers' which have obviously escaped inundation by being slightly higher than the surrounding areas. Today the sludge is readily identified as a very fine-grained, hard-setting, concrete-like `capping' overlying a well-developed, well-structured, pedal horizon, or in some instances, the gravels and sands of a creek bed. The thickness of the sludge capping varies between a few centimetres and three metres (Peterson, 1996). The buried topography was gently undulating, in direct contrast with the almost unnatural flatness of

Jan 1, 1997

Details are given of the excellent performance, outside Australia, of steel slag in road pavement surfacing. Laboratory tests and plant trials have shown Port Kembla BOF steel slag to be a material with properties suitable for producing asphaltic concrete which will maintain a high skid resistance in service under heavy traffic. The high density of steel slag is a factor which will result in a cartage cost penalty likely to restrict usage to close to its source.

Jan 1, 1979

What is the real value of your data?Given that the cost of collecting and analysing an individual sample is always rising, it is important to understand the true value of a sample and that you are confident that you receive good value for your exploration dollar. Unfortunately too many samples are still collected today that will end up as worthless data; a liability to those who own it and a hindrance to finding that ore body.

Jan 1, 1986

Thank you for the invitation to this forum today. I have a hectic schedule in the Mabo legislation process but it is important not to lose sight of the bigger picture and to attend today to talk to you about the Government's role in the development of our country.More importantly, I hope over the next couple of hours to get some feedback on developments in this area from people very much involved on a day to day basis.

Jan 1, 1993

By Hutchings AA

This paper describes MIM's experience in arranging and executing project financings for coal projects at Oaky Creek and Newlands and Collinsville and the port facility of Abbot Point.The financings had their origins in the late 1970's and culminated with the opening of these projects during 1983 and 1984.MIM's financing developments therefore span an important period in the development of resource projects in Australia.Resources projects have been growing in both scale and complexity of financing requirements.

Jan 1, 1985

Fluidised Bed Combustion technology has expanded since the first fluidised bed boiler steamed in 1974 with 58 companies currently supplying units. In Australia the market has been in small boilers and the goal of a limited attendance coal fired boiler has been achieved. On the world scene, the major incentive for development has been emission control with sulphur capture and low NOX. The potential of significant reduction in plant size is encouraging development of pressurised fluidised bed combustion.

Jan 1, 1987

Although the 'exi'stence of bauxite in Australia has been known for many years it is only recently that exploitation has commenced.. of the two most' important` deposits, strangely at almost diagonally opposite tips of the continent. Recognition of the importance. of the bauxite in the South/West corner came about initially through the efforts of a well-known Australian mining company which,` with some outside financial help, tackled the early exploration with commendable foresight and courage.

Jan 1, 1964

In the- past, at Great Boulder Gold Mines Ltd,, ,' s.. number of attempts ' ha'tre been made to remove water ' `solublo copper and' iron sa'lt's from calcined pyritic concentrates, but various problems have arisen and the methodsi ve been abandoned. A method of rapid washing has now been developed,, and although some problems still. exist,, a workable `process has boreh established .which. has; resulted in 'substantial savings of 'reagents used for. the. cyanidation of calcine

Jan 1, 1964

The reasons for including treatment of water in Whites and Intermediate open cuts in the overall rehabilitation strategy are given in the introduction. The target quality of the treated water also is discussed. Equipment selections are reviewed and reasons given as to why certain choices were made. The differences between this plant and an ore dressing mill are highlighted. An outline of the operating procedure is included along with a basic flowsheet. Cost estimates are briefly Discussed.

Jan 1, 1984

Direct seeding or regeneration of vegetation in Australia has been occurring in nature for about 400 million years! From the 1870's till the 1930's, direct seeding by man was used in the south-west of Victoria as a method of re-establishing native vegetation on broadacre farmland. The introduction of improved exotic pasture grasses and the wide-spread use of superphosphate from the 1930's lead to its demise as a farmland revegetation technique.

Jan 1, 1992

By Wickham P

Digital computer based control systems are used to implement control and monitoring over most unit operations in Mount Isa Mines Limited lead-zinc concentrator and copper concentrator. Implementation has been gradually devel- oped and expanded since the first process computer installation in 1969. Operations currently using high level control logic include crushing, grinding, on-stream analysis of flotation products, flotation reagent additions, and tailings thickening. Details of gains in metallurgical efficiency for each system are considered.

Jan 1, 1978

During its 60 years of existence the growth and development of Western Mining Corporation (WMC) has been greatly influenced by the men who led it. For the most part they, rather than any chance circumstances or good luck, determined the fortunes of the Company. This paper is essentially a series of biographical sketches of some of these men, together with a note of some of the major events which caused WMC to become the entity it is today.

Jan 1, 1993

This work describes preliminary laboratory testwork to study the relative leaching response to cyanidation and thiourea leaching of an oxidised low grade gold ore. The potential of an alternative lixiviant like thiourea to commercial processing of mine dumps is discussed by specific reference to selected case histories. It would appear that on the basis of the available published information, there could well be a case advanced for the acid thiourea leaching of sulphide concentrate tailings being subjected

Jan 1, 1994

Currently there is considerable interest in the production of DRI in Western Australia to take advantage of intense interest from the Asian market. Most DRI is produced using gas-based processes and is used as a feedstock in electric arc steel furnaces, otherwise known as mini-mills. This paper critically examines the technical and economic issues of various gas-based DR processes available today and recommends the most effective and attractive processes suitable for Western Australian iron ores.

Jan 1, 1996

The paper contains the publication of timber shapes recovered from the Burra Mines during open cut operations in the 1970s. The timber was in the process of being disposed of for fire wood. All timber shapes still in existence in September 1990 were drawn.The collection revealed a number of different types of caps and legs. There were also end plates and wall plates from what appeared to be a hanging sets of shaft timber.

Jan 1, 1993