Search Documents

By G Solly, S Parsons, P Leevers, S Ni

Hematite ore has been mined in the Southern Middleback Ranges as blast furnace feed for the steelworks at Whyalla, by what was then BHP, since 1991. With the floating of BHP Integrated Steel as OneSteel in 2001 and the subsequent loss of key mining personnel, breakdowns in grade control methods and procedures occurred. These were compounded by changes in orebody characteristics and grade distribution leading to poor reserve recovery and poor grade control, both which resulted in loss of control of ore specification and severe deviation from the mining schedule. As a result, a total review of grade control, mining method and scheduling procedures was undertaken as well as a review of contractor quality assurance. It was found that sampling methods were poor and unrepresentative, grade control blocking processes were outdated and did not reflect the geology of the deposit, the ore mining method was outdated and did not respect the geometry of the orebody, reconciliation methods were being completed globally and were not reflective of individual areas of the deposit, and that deviations from the mine plan were occurring due to access to high-grade areas outside the schedule in order to bring stockpiles back on grade. Based on these findings, updated sample splitter systems were fitted to drill hole rigs, double bench sampling was implemented (2 + 4 m samples as opposed to 1 + 8 m sample) and a three-dimensional cellular grade control system introduced to better reflect the geology and orientation of the deposit. At the same time ore mining was changed from front end loaders mining on 8 m benches to excavator mining on three lifts on 8 m benches; this aided selectivity and respected the geometry of the orebodies aiding cleaner recovery. Reconciliation is now completed on a blast-by-blast basis, which allows for quick and easy identification of poorly performing areas of the resource model that can then be incorporated back into resource model updates. Regular daily and weekly meetings are also held with emphasis on the mining schedule to ensure no deviation from the schedule in the long term. These improvements have resulted in a lift in reserve recovery both globally and locally associated at the same time with improvement in grade.

Jan 1, 2005

By Roach C

Exploration on the Callide Coalfield by Thiess Bros. Pty. Limited had reached the stage in mid 1976 where there was a need for a comprehensive appraisal of the coalfield geology. Exploration strategy in 1977 - 1978 was defined by the selection of the most attractive targets. All available literature, reports and plans were reviewed and borehole records assessed. The geology of the coalfield was placed in its regional setting and the genesis of the Callide Coal Measures described in a structural and sedimentological context. Their general form and extent was then examined by the technique of stratigraphic analysis through the interpolation and extrapolation of the available data. A "localized" reserve classification was drawn up and reasonable estimates of the various geological reserves produced, in terms of their reliability and depth of overburden. Quality trend maps were also produced. The resultant "base map" was virtually a summation of all the information to June, 1977, and the basis for the exploration programme in the 1977 - 1978 financial year. The technique allowed for "base maps" to be produced at almost any stage, each one a refinement of its Predecessor.

Jan 1, 1978

By J L. Edwards

High resolution, acoustic scanning technology has emerged in recent years as a powerful wireline tool for identifying the occurrence and orientation of structures and borehole breakout û the latter being a strong indicator of horizontal stress directions. While other wireline techniques such as dip metre and calliper logging can provide some of these data in a fairly rudimentary way, the quality and ease of interpretation of acoustic scanner logs provides a level of detail that significantly enhances the risk profile of the analysis which more than compensates for their additional upfront cost (MacGregor, 2002). As is often the case with such technology it is one thing to generate a data set that describes the attributes of the various features apparent in a log, and another to be able to analyse those data in such a way that their individual and collective impact on mine planning issues can be readily assessed (MacGregor, 2003). This paper describes a process for the interactive manipulation and visualisation of joint and breakout data to enable them to be effectively included in the mine design process.

Jan 1, 2009

Incompetent ore and country rock have caused stability problems in longhole open stopes. Fully grouted pre-placed cablebolts have reduced these by preventing ground relax- ation and joint dilation to maintain a self supporting rock structure. Larger atope spans can now be opened with the same or smaller pillar. Mining methods are expected to become less dependent on original ground conditions. Effect of spacing, orientation and stress distribution along the cablebolt is not fully understood at this stage and requires more Observation.

Jan 1, 1977

By P T. Hick, T J. Cudahy, M S. Caccetta

Dust derived from mining and handling of ore has been identified as a major concern for the mining industry in Australia and may be critical to the future viability of some resource industries (CSIRO, 1999). Operational techniques to derive accurate measurements of anthropogenic dust on vegetation and infrastructure are necessary for the long-term management and monitoring of the environment surrounding mining operations. Airborne hyperspectral VNIR-SWIR systems can potentially provide these monitoring data. This paper outlines a method developed for deriving quantitative measurements of dust quantity on mangroves using remotely-sensed airborne hyperspectral data. The results show that it is possible to detect and quantitatively map iron oxide dust distribution using properly calibrated airborne visible to short wave infrared (VNIR-SWIR) data.

Jan 1, 2002

By P D. Fraser

This paper examines the new water-hydraulic (hydro powered) drill rigs that have been developed and proven in the last decade primarily in tabular, shallow-dipping, narrow-reef, hard-rock South African mines. These include - drill rigs for flat end tunnel development, narrow inclined raises and winzes, large inclines and declines and long hole based developments such as orepasses and vent raises. The hydropower technology rigs offer advantages both in safety and performance over traditional compressed air powered, hand-held development are generally more cost effective than imported oil electro-hydraulic drill rigs. Furthermore, hydro powered rigs are inherently energy efficient. The benefits of hydropower are discussed and a æcomprehensive development modelÆ is presented which demonstrates that orebodies can be accessed in significantly shorter times. æLocalisedÆ half level hydropower systems are introduced and a range of ancillary equipment available is listed.CITATION:Fraser, P D, 2012. The use of high-pressure, water-hydraulic (hydropower) technology in South African narrow-reef, hard-rock mines, in Proceedings Narrow Vein Mining 2012 , pp 229-236 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 26, 2012

The Auscoke project has reached-a stage where a pilot plant nominally able to produce 100 t.p.d. of coked briquettes is being brought on stream during Nov. 1971 . The targets for this stage of the project are to establish the technological and economic value of Auscoke for the iron blast furnace, and to verify the commercial feasibility of large scale plants. The project originated at the B.H.P. Central Research Laboratories (C.R.L.) and work to date has shown that using a two stage contin- uous process, strong large coke can be produced at good productivities from medium or low volatile poorly caking coals. General features of the pilot plant and processing are discussed.

Jan 1, 1972

By Royston, Woods R

ANI Bradken Vortex Pulp Lifters and Grates, both as original equipment and retrofitted to existing SAG mills, are now in field operation. The development of the Vortex leading curve pulp lifter was based on an analysis of traditional radia

Jan 1, 1997

The Lake Rotokaua sulphur deposit, near Taupo, New Zealand, is a lacustrine sedimentary ore body, 220 acres in area and from 7 ft to 96 ft thick, containing, within the area drilled to date, some 20 million long tons of ore averaging 25% elemental sulphur in unconsolidated tuffaceous diatomaceous clay, overlain by about 120 ft of pumice sand and by the shallow Lake Rotokaua. An additional amount of perhaps 4 million tons of sulphur is regarded as probable in the area remaining to be drilled. Current economic studies cover the problems of mining an unconsolidated water-saturated formation with some residual thermal activity nearby; conservation and restoration after mining in a scenic recreation area; beneficiation of the ore and extraction of high- purity sulphur, principally for fertilizer manufacture. The deposit has additional importance as a pointer to possible further discoveries in the Thermal Region.\

Jan 1, 1971

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

Gold Fields Ghana Ltd (GF Ghana) currently operates an underground mine at Tarkwa, in south--west Ghana. The mine was operated by Tarkwa Goldfields Limited, a wholly owned subsidiary of the State Gold Mining Corporation of Ghana (SGMC). The mine was making operating losses and in a poor state of repair. Tarkwa Goldfields retrenched all the staff and GF Ghana assumed management responsibility for its own account on I July 1993.

Jan 1, 1997

Close spatial relationships between the deposits of the Etheridge Goldfield (23,000 kg of bullion) and various regional geological and geophysical features suggest that genesis of the ore deposits was a multi-stage process that started with magmatic and metamorphic stages in the mid-Proterozoic, climaxed with structural and hydrothermal stages in the late Palaeozoic and terminated with an oxidation enrichment stage in the Cainozoic. Acceptance of this hypothesis permits classification of the Georgetown region into areas likely to contain deposits of the Etheridge type and those unlikely to do so. Consequently there is little scop- for the discovery of extensions of this field. However, the stratigraphic interval between the source rocks of the Etheridge field and stratigraphically higher host rocks of the Croydon field may contain disseminated replacement gold deposits of the Carlin type. The potential host (pyritic carbonaceous, and locally dolomitic siltstone of the Candlow Formation) is locally faulted and cut by granitoids and the extension of a mineralised, long-standing zone of structural weakness.

Jan 1, 1980

The potential of the developed multi-dimensional analysis system to assist interpretation from large data sets through derived digital mapping models is presented accompanied by preliminary results. The concept learning model is original and its application general. Applications exist in general science, engineering, earth resource management and economics. The developed system incorporates advances in machine learning, neural networks, object-oriented software engineering, knowledge representation and fuzzy logic. ' The specific application presented involves automatic earth resource modelling and assessment involving geological theories of mineral potential. The developed system functions as a new and powerful mineral exploration tool, To date the model has been trialled on an earth resource database and several published data sets. A more general potential application is knowledge discovery within databases. The specific theory that is tested in the experimental results is the nature of the cause-effect relationship between the hypothesised geological causes and the measured effects within a previously published test survey. Also integrated here are a neurophysiological cerebellar model of human learning, a new concept similarity measure for pattern recognition, modelled components to explain human concept formation through knowledge discovery and a means of permanent representation.The implementation is as a new artificial neural network architecture functioning as a hybrid expert system. Understanding of programmed concept learning is extended through the model. Also established is a basis for a new approach to multivariate data analysis. Spatial analysis for decision support is integrated over many dimensions, relationships, data types and data modes. Application of the developed methodology and system adds value to data bases. Discovered knowledge is represented as new generalisations, interpolations, classification hierarchies, aggregations and associations within a dynamic, maintainable and reusable integrated knowledge framework. New digital knowledge products and intelligent access follow. Permanently stored, maintainable, easily accessible and discovered knowledge improves decisions through extended hypothesis testing, spatial data analysis and inferencing, prediction, logical deductions and explanations.

Jan 1, 1995

During the past 18 months several import- ant hydrocarbon discoveries have been made in the Dampier Sub-basin, which is a sedimentary area lying entirely offshore from the Precambrian Pilbara Block in the southern part of 'he Northwest Shelf of Western Australia. This sub-basin is a major sedimentary downwarp forming a northern extension to the Carnarvon Basin. This extension is bounded to the north by the De Grey Nose, separating it from the Beagle Sub-basin. To the south the Dampier Sub-basin merges with the Barrow Sub- basin. Extensive seismic data combined with results from exploration drilling show that the Dampier Sub-basin is a complex depositional basin containing over 20,000 feet of sediments which are mainly Triassic to Recent in age. Tectonically the sub-basin can be divided into seven main structural elements. In a northwest to southeast direction these are the Rankin Platform, the Kendrew Trough, the Madeleine- Dampier Trend, the Lewis Trough, the Legendre- Rosemary Trend, the Enderby Fault Zone and the broad Pilbara Shelf. Permian sediments were encountered in only one well drilled to date in the sub-basin, but Triassic and younger sediments are extensive. The section consists initially of 'hi -_D 7 ri ,~ ~, , i , Derived

Jan 1, 1973

One of the most difficult places to ventil ate in any mine is the working face area of an advancing mine heading. With an ever changing configuration, continual modification and extension to the ventilation system is necess- ary to maintain an adequate supply of fresh air and to control mixing and recirculation. Methane emissions and high dust levels as coal is broken and removed from the face area can produce unhealthy and dangerous conditions if ventilat- ion is not adequately monitored. An understanding of the air flow patterns which develop through use of different face ven- tilation systems can be reached by undertaking underground measurements or through observations using physical models. Tests undertaken by the author to determine the adequacy of different system-configurations are discussed together with approaches adopted by others working in the United States. Various new methods have been proposed for improving face ventilation beyond that sustained using conventional brattice curtain or tubing systems. The adequacy of some advances adopted by mining companies to improve ventilation while maintaining output efficiency is discussed.

Jan 1, 1983

By N B. McCaffrey, V Glenn, C Johns, P D. Erskine, A T. Fletcher

"Underground coal mining is the dominant method of extracting thermal and coking coal in the southern and western coalfields of New South Wales. Monitoring mining-related subsidence forms an important component of environmental impact assessments and subsidence management plans, particularly when there are conflicts between the interests and requirements of mining and environment and community groups. However, there are few specific guidelines for monitoring the impacts of subsidence on terrestrial and aquatic ecosystems, leading to inconsistent policy approaches and highly variable abilities of monitoring programs to accurately detect biological change.This paper highlights the use of a conceptual framework to guide the development of a long-term ecological monitoring program at an underground coalmine in the Western Blue Mountains, New South Wales. Two pilot studies are described: determining the level of observer agreement to assess the condition of a vulnerable tree species (Capertee Stringybark) comparing field sampling methods for detecting a rare heath shrub, Epacris muelleri, using a power analysis to determine sampling intensity requirements.These examples demonstrate that investment in initial pilot studies to test different monitoring approaches can have long-term benefits for stakeholders by more confidently being able to detect potential impacts.CITATION:McCaffrey, N?B,?Glenn, V, Erskine, P?D, Johns,?C?and Fletcher, A?T, 2014. Detecting long-term ecological impacts of subsidence from underground coal mining – a tale of two pilot tests, in Proceedings Life-of-Mine 2014, pp 139–152 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 16, 2014

By Gray E, Banks J

In mine site revegetation, exotic grasses are more commonly used than native grasses. This is due to unavailability of native grass seed on a commerical scale and lack of information on agronomical aspects of native grasses. This paper lists a number of native grass species that have the potential to grow well on mine sites, and provides some information on their seed collection, processing and germination. Further, it demonstrates via results of a field trial conducted at Ranger Mine spoil the relative performance of ten native grasses and Rhodes grass. It is concluded that (i) some native grasses have similar ability to grow on mine spoils compared to Rhodes grass and (ii) the use of native grasses have added advantages in ecosystem restoration.

Jan 1, 1994

By A Suokas

Boliden Tara Mines Ltd, located in County Meath Ireland, produce in excess of 2.5 million tonnes per annum of ore from the underground resource located 40 miles north west of Dublin. The zinc-lead ore is mined using long hole open stoping techniques, with ore treated on site. The operation is continually searching for new ways to improve productivities at the mine, and have employed a detailed data acquisition and reporting system on site to provide feedback around performance. One area where both Boliden Tara Mines Ltd and Orica Mining Services believed improvements could be made was in the application of bulk emulsion technology through an Orica supplied but Tara operated Maxipump Delivery System for all production and development blasting at the mine. Both parties committed to the evaluation of this technology at the mine, however the capital cost and technical and economic changes meant the project needed to be diligently investigated and any improvements documented. The first stage of this project was for Orica Mining Services personnel to visit the operation, and conduct a detailed analysis of the operationÆs performance over the past 12 months. The next step in moving forward was then to commission and utilise the customer operated emulsion system at the mine. This was then followed with the collation and analysis of data from the demonstration period to examine and document the benefits of the system. This paper is a summary of the observations made during the site inspection and the data analysed to date, and has been used in determining operational and financial improvements in the comparison between a Maxipump Emulsion Service and the current ANFO loading systems.

Jan 1, 2005

By P Jago

KCGMÆs Fimiston Open Pit, located in the centre of the historic Golden Mile, is situated above some 3000 kilometres of old underground workings. These workings, both level and vertical, present significant safety and operational problems in the pit. One of these challenges is in safely drilling void areas so that they can be charged and blasted effectively. Current drilling practices in these areas require machines that can only drill 115 mm holes on a smaller pattern than the standard blast pattern. This results in more time and cost to both drill and charge these areas. Any other method currently available to drill out these areas involves putting operators in a potentially hazardous situation by being too close to the void area being drilled. Not effectively drilling and blasting these areas leads to hazardous situations further in the mining cycle including oversize, large toe and uncollapsed voids. Ineffective blasting also causes reductions in mining productivity and mine to mill performance. In response to these issues, KCGM has commissioned the implementation of a fully remote controlled DM45 blast hole drill rig to drill out selected void areas. The remote system, installed in conjunction with Ausdrill Ltd and GM Mining Electrics, is designed to operate similarly to a tele-remote bogging system with the operator controlling the drill rig from a separate control cabin via radio signals and video feed. This allows KCGM to drill in areas of higher risk without exposing the operators to voids. The drill rig will also be able to drill standard patterns through some specially selected void areas, reducing costs and extra time associated with drilling and charging void affected areas. The remote rig is expected to provide a number of benefits, both in the drilling process and in further downstream operations. Costs of drilling in void areas are expected to decrease with standard patterns instead of smaller patterns being drilled. Safety and operator comfort are also expected to increase through removing the operator from the pit floor. Blasting is also expected to see significant improvements through increased ease of charging void areas (because of larger holes and standard patterns), more consistent patterns resulting in less secondary blasting and toe and an overall improvement in the speed and cost of charge-up practices. This more consistent blasting will also improve shovel productivity, crusher performance and overall mine-to-mill efficiency. This paper presents an overview of the development of the remote controlled system, including modifications that have occurred since commissioning. It explains some of the problems encountered and how these have been solved. Key issues for operational success will be identified and explained with a view to making future implementations easier. Factors used to assess the performance of the remote controlled rig will also be explained in further detail and used in a preliminary assessment of the rigÆs feasibility.

Jan 1, 2003

Mining is an intensive resource development industry, where operations are often of relatively short duration and can result in dramatic impacts on the natural environment during the operational period and for many years post mining. An integral component of all mining operations is water û through exploration, resource definition, mine development and operation, rehabilitation and the long-term post-mining land use. Water is a basic requirement in the provision of worker amenities, in drilling, as a means of dust suppression, as a medium for washing or processing the mine product, and as an aid in establishing vegetation on post-mining landforms. Water also plays an important role in mobilising environmental contaminants and is the primary medium for the transport of contaminants off the mine or processing site into the wider environment. It is for this second reason that the mining industry considers water management as a key component of mine management. Cost-effective water management relies on planning that incorporates a total mine system approach commencing prior to exploration and continuing through to rehabilitation and decommissioning. One of the primary considerations that will provide confidence to both government and community at the time of mine closure and lease relinquishment, will be the evidence that any water originating from, or passing through, the mine site is of a quality that will not have any negative impact on the surrounding environs into the future. The role of vegetation in stabilising disturbances to a landscape is well known, as is the recognition of vegetation being a fundamental component of the water cycle through the physiological processes resulting in the transfer of water back to the atmosphere through transpiration. In terms of water management at a mine site, the two crucial issues are the æquantityÆ and æqualityÆ of water that enters a receiving æoff-leaseÆ catchment. In terms of tolerances of the receiving environment, the total load of potential contaminants becomes critical, a reduction in which can be achieved through reduced volumes of water discharged, reduced chemical and physical concentrations of contaminants in that water, and ideally, both. This paper examines the potential role of vegetation in reducing the quantity of water released from a site, and secondly considers vegetation in the role of influencing the quality of that water.

Jan 1, 2003