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By Favreau RF

Over the last 20 years the blasting industry has progressed from the stage of being artform to a science as it is today. The use of computers to simulate blasting results has allowed blasting engineers to accurately pre- dict blast results and to optimise their blasting. This paper describes the computer blast simulator called BLASPA and its various applications in blasting. BLASPA allows the blasting engineer to predict blast results given known details of explosive properties, their distribution, rock type and properties, hole size, burden, spacing, collar and subdrill. The simulator runs mathematical situations and outputs numerical estimates of fragmentation and muckpile results. The paper discusses results which show that the mathematical outputs correlate very closely with actual results seen in the field, thus confirming the validity of the simulator. BLASPA can be used to help improve blast design by predicting stress levels in the rock mass and consequent rock breakage.

Jan 1, 1986

By Fabjanczyk M. W

A limitation to present theoretical roof reinforcement design methods is the inability to derive accurate and quantitative information about the roof rock condition and the action of reinforcement at various excavation stages. To obtain the information required to assess roof rock stability, detailed monitoring of the in-situ behaviour of reinforcement and roof strata is required. Reliable instru- mentation and techniques have been developed for use in underground coal mines to identify the geometry and magnitude of displacements occurring in roof rock and the forces generated in reinforcement. The use of such instrumentation allows an accurate assessment of the in-situ capability of reinforcement and the mode of reinforcing action developed. In-situ monitoring can supply data required for the practical design of reinforce- ment and assess the potential stability of current designs. The use of such data together with mine wide appraisal of rock and stressfield considerations, can allow roof reinforcement to be designed on the basis of a predicted roof Response.

Jan 1, 1986

This paper describes several sources of external dilution affecting the stope walls during underground sub-level and bench stoping. Factors which control ground behaviour such as the geometry of the openings, the influence of geological discontinuities, stress re-distribution and blasting practices are discussed. Crown stope instability due to stress concentrations induced by changes in the excavation geometry, is discussed and the most efficient ways to sequence blasting within a stope are analysed. Effects of undercutting by blasting, blast damage in the near field and cut-off slot blast designs are analysed. The influence of dynamic loading on the exposed walls as well as the practice of blasting fill passes within stope crowns are discussed.

Jan 1, 1995

By Schon RW, Stephens CJ

The Whitsunday Volcanics occupy most of the offshore islands from the Whitsunday Group, southeastwards through the Cumberland and Northumberland Groups, possibly extending to the mainland adjacent to Shoalwater Bay, a distance of 370 km. Some of the islands of this group are granitic, but preliminary Rb-Sr data indicate these to represent Permo-Triassic basement. Cretaceous volcanism is interpreted to have occurred during initial rifting prior to the continental breakup of northeastern Australia and subsequent development of the Tasman Basin.The volcanics comprise mainly lithic ignimbrites, with local development of inter-bedded surge and bedded tuff, accretionary lapilli tuffs, lithic concentration zones, and lag deposits. Isolated fluidual rhyolite and dacite domes occur. The deposits are considered subaerially emplaced. A Rb-Sr isochron age for volcanism of 110 Ma is determined from new data. The total thickness of the volcanics is unknown, but a minimum thickness of 4-5 km on Whitsunday Is. is suggested. Eruptive centres are inferred to be distributed throughout the volcanic zone. The volcanics are cut by numerous, dominantly near N-S, dykes ranging from dolerite through to rhyolite in composition.Chemically, the volcanics and dykes exhibit a continuous range of compositions from basaltic andesite, through andesite, dacite, to rhyolite, with minor more alkalic compositions. Phenocryst mineralogy in the silicic rocks is mainly plagioclase, augite, and Fe-Ti oxides, with less frequent quartz and hornblende occurrence. Sr and Nd isoptic compositions for volcanics and dykes are close to mantle values. These data are tentatively interpreted in terms of a lower crustal magma arc source separated from the mantle only a geologically short time prior to Cretaceous magmatism.

Jan 1, 1990

By Ranklin W. J

The mechanism and rate-limiting step of carbonaceous reduction of zinc from slags was investigated in the laboratory. Disks of graphite were rotated in ZnO-containing slags at various speeds for fixed periods at 1250 to 1325¦C. The mass loss was used as a measure of the amount of ZnO reduced. Application of the Levich equation indicated that at rotation speeds at which it is valid, the reduction was chemically controlled with an activation energy of 27 kcal/mol. At zero rotation speed the reduction of ZnO by carbon appeared to be slag-phase mass transfer controlled with an activation energy of 38 kcal/mol. An increase in the FeO content of the slag increased the rate of reduction while an increase in sulphur content decreased the rate of reduction. When FeO was present in the slag, reduction appeared to occur by a combination of indirect reduction of ZnO by carbon and by reduction by FeO with reduction of Fe203 back to FeO by carbon. The effect of sulphur was consistent with a surface blockage mechanism due to the surface active nature of sulphur in slags.

Jan 1, 1993

By Spottiswood DJ, Kelly EG, Bull WR

An empirical model of a 254mm water-only cyclone treating minus 17001im coal has been developed. The model includes the prediction of by-passing, SG50 corrected, water split and the use of a single equation forthe reduced performance curve of particles in the range 1700-106pm. Particles finer than 106pm did not separate according to specific gravity. Simulations using the model showed the water-only cyclone performance to be dependent more upon feed size distribution than washability when the feed contains high-ash fines, but that, with a deslimed feed, the yield and ash content of the over-flow should be controllable by altering feed rate or feed pulp density.

Jan 1, 1985

By Dhawan AK

On 8 July 1993, a landslide of about one million cubic metres of rock blocked the river Satluj near Sanjay Vidyut Pariyojana - Bhaba project and caused flooding into the Bhaba Power House (120 MW) resulting in suspension of power generation. The concerned authorities desired an early removal of the blockade by an underwater blasting operation into the over topping water to reduce the water level at the blockade and resume power generation in the power house. In the absence of underwater drilling, it was essential for the blasting technique to be used where no cavity to confine the explosive was required. For this reason mud capping and plaster shooting with directional throw were used and additional specially fabricated mild steel pipe charges were used under high current for an underwater trenching operation. By employing these techniques the river blockade was removed up to the required depth and on 8 September 1993 the Power House resumed the power generation.

Jan 1, 1995

By Tien J. C

Many factors (type of coal mined, water pump pressure, wetting agent concentration, etc) will affect the performance of a dust suppression system using a water spray in an underground coal mine. While a two-level factorial method is useful in

Jan 1, 1994

By Yaroshenko YuG, Bokovikov BA, Gordon YaM

Problems of the effect of the number of tuyeres and their parameters on the uni- formity of gas distribution are invest- igated with the use of the authors' devel- oped mathematical model of the movement of gases and materials in the blast furnace. It is shown that the improvement of uni- formity of gas distribution with an increase in the number of tuyeres has a damping character. An analysis of the errors of the specified assumptions of the hypothesis concerning the potentiality of the gas movement in the bed is carried out. It is established that the potential approach model gives good results with the determination of the discharge of gas and its stress field, but is not useful for the calculation of local velocities of gas in the raceway. The results of trials of calculation investigations of the dynamics of form- ation of the raceway and the voidageòfield in beds of burden materials are presented in the concluding part of the paper.

Jan 1, 1981

By M Wen, J Gerit, C A. Pelletier, D Muggli

On-land waste rock dumps at BHP Billiton Base MetalsÆ Island Copper Mine (ICM) near the northern end of Vancouver Island, B.C. continue to discharge ARD. These waters, which amount to approximately five million cubic metres each year, are injected into a three-layer, meromictic pit lake for treatment. The top layer is brackish water, replenished by each yearÆs rainfall (amounting to nearly 2 m/year). This top layer of water must meet effluent permit limits for heavy metals. This water eventually exfiltrates through a æbeachÆ waste rock dump, which is 93 per cent submerged along the north shore of Rupert Inlet. The middle and bottom layers of the Pit Lake are saline and currently oxic (2 mg/L dissolved oxygen) and anoxic (0.03 mg/L dissolved oxygen), respectively. Spreading of a liquid fertilizer every ten days throughout the top layer results in plankton and bacterial blooms that scavenge zinc, copper and cadmium out of this layer eventually to become mineral sediment in the bottom of the pit lake. Adsorption on planktonic skeletons and mineral precipitates also scavenges these dissolved metals from the middle and bottom layers to form bottom sediment. Sulfate reduction has recently begun in the bottom sediments. Diagenetic processes in the bottom sediments will eventually transform most of the dissolved heavy metals into insoluble sulfides. Cycling of ferric iron between the sediment and the water column and back seems to contribute dramatically to the biogeochemical metal removal processes. This biogeochemical system serves to maintain the top-layer water well within permit limits for discharge to the environment.

Jan 1, 2003

The design of a sand pump is similar in principle to that of a water pump but differs in several areas. Results of experiments on sand pump performance have been summarized and values of design parameters quoted for optimum results. Typical performance data are also Included.

Jan 1, 1973

By Walker K, Burton RC

An outline of the ventilation and refrigeration requirements of deep South African gold mines is presented. This is followed by a brief description of the history of controlled recirculation in mines and the practical and economic benefits such schemes can offer. The potential hazard of a fire in a recirculation system is discussed.The major part of the paper describes the first large-scale field trial of controlled recirculation to be conducted in South Africa. Emphasis is placed on the monitoring system that was used for data acquisition during the trial, and also on a safety system designed to shut off the recirculation fans in the event of a fire.The paper concludes with a review of the latest development work taking place on recirc-ulation safety systems.

Jan 1, 1985

By Van Barnefield J G

This paper is based on an evaluation project engaged upon jointly by Mount Isa Mines Limited nnd" IBM Austra]ia Limited. Mount Isa Mines Limited produces most of its copper from large underground open stopes within massive orebodies. Variations in the position and shapes of these stopes can result in improved metal recovery. An interactive graphics system has been developed to assist the mine design engineer optimise his design. The system can assist the engineer throughout the orebody visualis- ation, initial design and optimisation phases of his design. At any stage the engineer may call upon the display of gridded mesh data, digitized ore outlines or existing stopes or development (drives, cross-cuts). This information may be viewed in plan or any vertical section or in three dimensions with rotation. Tonnage and grade calculations may be quickly performed for initial stope outlines or for modifications to them during the optimisation phase. The system design is highly modular. An array of functions for the manipulation of coordinate and line information may be linked with the development or stope design functions in whichever way the designer desires.

Jan 1, 1977

By J Balzary, A Mohais

Dynamic market and operating conditions, coupled with an environment in which multiple objectives and trade-offs are common, pose major challenges for planners and schedulers working in any mining entity. Many mining companies recognise the need to shift from a siloed mining-focused push model to an integrated value chain, demand-driven approach, but there are still fundamental barriers in business process and the supporting technology preventing a consideration of end-to-end optimality.This paper presents some elements of experiences working with companies to adopt such advanced approaches. In addition to algorithmic elements, an approach to phased and gradual deployment of progressively more sophisticated optimisation models is described. From a practical software adoption perspective, it is believed that this last concern is also of primary importance. Next generation approaches to the optimisation of complex bulk commodity demand chains, namely iron ore and coal are presented, with case studies in the world’s largest integrated operations in Western Australia and Queensland from the raw material mined through to market. Utilising accurate simulation models supported by metaheuristic optimisation techniques, a range of ways to engineer a dynamic decision support framework that can adapt and change with the inevitable changes in commodity markets is explored. Objectives such as total revenue, margin, cost, NPV, throughput, asset utilisation, contractual penalties and bonuses, and energy consumption can be managed simultaneously across the mine, plant, logistics network, port operation, shipping and sales domains.CITATION:Balzary, J and Mohais, A, 2014. Consideration for multiobjective metaheuristic optimisation of large iron ore and coal supply chains, from resource to market, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014, pp 213–222 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

The winning and upgrading of mineral raw materials necessarily includes size reduction, which serves the liberation and production of marketable products from highly valuable and bulk materials. For crushing, the following factors can be duly accounted for depending on material type and the selection of the suitable machine: ò producing a particular size distribution, ò producing a particular grain shape, ò selective comminution, ò gentle comminution, and ò producing a size range required by a specific process and/or for a specific product.

Jan 1, 1993

By Case JE

Complete Bouguer and isostatic anomaly maps compiled for Costa Rica provide new insights into the crustal structure and mineralization. Terrain corrections were approximated from the station to a radial distance of 167 km by computer using a 3- minute digital elevation model of Costa Rica and surrounding areas. Isostatic corrections, based on Airy-Heiskanen compensation, were also calculated from 0 to 167 km using the 3- minute elevation model and from 167 km to 180 degrees using combined topographic and isostatic reduction maps. Costa Rica can be divided into four main terranes based on gravity data: a Pacific coastal region, a Pacific inland area, a central region, and a Caribbean coastal region. Negative gravity anomalies along the Pacific coastal margin correlate with an offshore sedimentary basin, and large positive anomalies correlate with mafic and ultramafic igneous rocks on the Santa Elena, Nicoya, and Osa Peninsulas, and at Puerto Quepos. Pacific inland anomalies are separated from the Pacific coastal region by a steep gravity gradient, and over the Coast Ranges a major gravity low overlies a thick section of low- density sedimentary rocks. In the central region, a major gravity low occurs over a thick low-density Quaternary volcanic complex in the Cordillera Central, north of San Jose. A prominent feature of the Caribbean coastal region is an interrupted gravity low over the Limon Basin that reflects a thickening of low-density sedimentary rocks. A conspicuous gravity lineament, trending northeast separates northern and southern Costa Rica. The lineament is defined by the termination of several major gravity anomalies including those over the Coast Ranges, Cordillera Central, Puerto Quepos, and Limon Basin. In addition, the lineament correlates with other geological and geophysical data including: northeast-trending faults, the southern limit of large Quaternary volcanoes, the segmentation of the middle America volcanic belt, and a seismicity gap. This lineament may be the expression of a previously unrecognized major northeast- trending fracture zone in central Costa Rica. An important economic implication of the gravity lineament is a correlation with the termination of gold and porphyry copper deposits in Costa Rica.

Jan 1, 1987

The mechanisms of fragmentation in homogeneous materials and structured rock mass are reviewed. A method previously used to predict vibration damage to the remaining rock is extended and shown to be valid for the prediction of fragmentation in the rock mass removed by blasting. The effectiveness of different explosives in different types of rock blasting is discussed.

Jan 1, 1990

By Barnes R. G, Agostini A, Lewis P. C

The Mineral Resources Audit is a five-year Program established to produce a comprehensive and objective assessment of the mineral resources of New South Wales, including prospective resources. The goals of the Program are to improve planning and land use decision-making; attract exploration and minerals related investment; help the Department to identify and fill gaps in knowledge; and develop methods to identify and quantify resource potential and prospectivity. To achieve the goals of the Audit it is necessary to assemble and enhance a large amount of information and it is necessary to spatially analyse this information using computer-based Geographic Information Systems (GIS) which allow the collection, storage, transformation and display of large quantities of spatial data. An extensive range of both map-based and textual data can be employed in spatial analysis and resources and geoscience modelling. In order to use this information, data sets have to be corrected and standardised. Many data sets need to be classified. An objective of the Audit Program is the spatial analysis of the State, region-by-region, and the release of cleaned-up multiple digital data sets as packages which include upgraded mineral deposit information, 'seamless' geological map layers showing lithology, structures and stratigraphy, and processed and classified geophysical map layers. These regional packages are important reference sets for the mineral resources industry and will assist delineation of regional exploration targets.

Jan 1, 1995

Australian continental crust has accreted and consolidated by thirds: 1/3 during Archean time, 1/3 during Early to mid- Proterozoic time, and 1/3 during latest Precambrian to mostly Paleozoic time. The progression of orogenic systems and the crustal consolidations they represent seem not fundamentally different in basic orogenic processes from better known Mesozoic-Cenozoic examples in that accretionary, continental margin, collisional, and intraplate intracratonic inverted and/or reactivated systems are all recognizable in the tectonic evolution of Australia.

Jan 1, 1995

By T J. Beardsmore, N Wyche, D Flint, T J. Griffin

Western Australia (WA) is currently the world’s largest iron ore producer, and mining of its huge reserves and resources of iron ore has become a critical part of the state’s economy and regional development. Iron ore exports from WA have reached 760 Mt/a, corresponding to shipping more than one Mt per turn-of-the-tide from the state’s ports. The iron ore sector dominates all commodities produced in WA, and in 2016 accounted for 77 per cent of the state’s royalty receipts, 56 per cent of mineral and petroleum exports (by value) and 50 per cent of mining industry employment. Expenditure on exploration for iron ore (including that for resource estimation and conversion to ore reserves) has declined markedly, from its record peak of $1100 M in 2012 to $280 M in 2016, placing it second after gold. Foreign investment has been a key element underpinning development of the iron ore industry from the 1960s until today, and will likely continue to be so into the future.CITATION:Flint, D, Wyche, N, Beardsmore, T J and Griffin, T J, 2017. The importance of iron ore to Western Australia’s economy, in Proceedings Iron Ore 2017, pp 7–12 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017