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By Y Ren

The algorithms employed by the commercial tools are either heuristic algorithm or iterative optimisation of a subsystem. This often results in a suboptimal schedule. In this paper, the author presents a new scheduling algorithm that incorporates with a novel stockpile configuration system, an improved algorithm on multiple processes and a mixed-integer linear programming (MILP) global optimisation model. It can simultaneously optimise stockpiles, blending, multiple processes as well as multiple mines. In addition, it allows the user to interact with the solution to adjust the solution to be practical and desirable.CITATION:Ren, Y, 2013. A simultaneous optimisation tool for open pit mine scheduling, in Proceedings World Gold 2013 , pp 427-432 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By M Gill, A Mathias

The mining industry has always been cost-focussed but in recent times mining companies have moved towards obtaining a competitive advantage through the implementation and sustainability of best practice in the areas of improved safety, operating costs, quality and productivity. This is the concept of Value In Use û that mining companies see value generated all the way to the bottom line through improved change, and those changes become an established mine practice. Many mining companies do not have the resources or the knowledge to sustainably achieve such an outcome. This has led to companies looking to their suppliers to deliver measured value to their business through partnership arrangements. Suppliers have been able to leverage their knowledge of products, product applications and services to offer alternative supply agreements that bring greater returns to their businesses while improving supplier/client relationships. Orica has developed such a partnership with Coal & Allied in the form of a Continuous Improvement Program. Coal & Allied is based in the Hunter Valley region of NSW and is the largest coal producer in that region. Both parties are contractually bound to jointly deliver Value In Use projects to Coal & AlliedÆs Hunter Valley Operations and Bengalla mine sites. It is the request of the Orica and Coal & Allied Steering Committees that this paper does not include the details of actual projects or the costs or key performance indicators associated with the program. This is to maintain the competitive advantage to both Orica and Coal & Allied through the implementation of such a program. It is in the writersÆ opinion that this paper does not lose any significance through this restriction as the most important component of the Continuous Improvement Program is not the projects themselves but the methodology behind them. With this in mind the paper will discuss the development of Value In Use offerings, the key aspects of the Coal & Allied and Orica joint program, what is a Value In Use project, how to measure its value, finally why and even more importantly what makes this program is a success.

Jan 1, 2004

By R Wedmaier

Henty Gold Mine is an underground operation producing 100 000 ounces of gold per annum. The original mining method used was flatbacking with paste fill. However, a non-entry method û uphole benching û was introduced in 1998 to recover the deteriorating crown pillars. Initial challenges were encountered, including poor drilling accuracy, difficulty in charging holes and poor rise performance. These challenges were overcome by a Continuous Improvement Team, consisting of mining engineers, supervisors and miners. Following this, the Team implemented further changes aimed at reducing ore loss and dilution. A second area addressed by the Team was development blasting, where innovative detonator technology known as the ExelTM DevelDetTM was introduced and rapidly accepted by the operators. Continued use of the ExelTM DevelDetTM resulted in a number of benefits, such as easier bogging, less perimeter damage, faster charging and hook-up and decreased wastage. Finally, improvements were made in the area of explosive handling, where competency-based training of operators was conducted and manual handling of ANFO has been significantly reduced by the introduction of the MiniMoverTM into the underground magazine.

Jan 1, 2001

Declines for both access and rock haulage are replacing shafts for mining relatively shallow deposits of down to 1000 m below surface. Where the orebody does not outcrop and where surface access may be restricted, it is often necessary to drive long dead end headings before a connection can be made back to surface and a ventilation circuit created. In hot tropical areas and where large diesel powered equipment is used for mining, heat may also be a problem at these relatively shallow depths. The normal design criteria based on statutory limits and good practice used to evaluate ventilation and cooling requirements in terms of air velocity, dust, gases, diesel exhaust dilution, re-entry after blasting and heat stress are described in this paper. These are then used to design and cost alternative auxiliary ventilation systems that include leakage based on general fan performance curves and typical duct systems. The implications of the current European Community recommendations regarding nitrous fumes are also briefly considered. The actual problem relates to a 2100 m long decline that may have to be extended to 3000 m long without a connection to surface or through ventilation and is located in a hot tropical area where the surface wet bulb temperatures may exceed 25¦C for more than a third of the summer period. Once the preliminary ventilation design is completed, the auxiliary ventilation system can be modelled and simulations undertaken that incorporate heat and moisture transfer routines with the objective of determining the cooling load and amount of refrigeration required. Cognisance is taken of cyclic diesel operations and the thermal flywheel effect of the surrounding rock on the wet and dry bulb temperatures resulting from these operations.A suitable modular cooling system located at the portal is described and optimised with capital and operating costs of both the ventilation and cooling systems provided.

Jan 1, 2005

The continuous casting of zinc alloys has been of fundamental importance for many years in the production of a number of products, including sheet for architectural applications, battery cans for dry cells and wire for metallising. The intrinsic benefits of continuous casting, including efficiency and high tonnage capability, uniformity of metallurgical structure and properties, and absence of voids and other defects, have contributed to the success of these products. Less well known, but of growing importance, is the more recent application of continuous casting technology to the production of zinc alloy bar stock products, including bearing stock, machining bar stock, forging stock and cathodic protection anodes. A wide range of zinc alloys are now continuously cast in a variety of cross sectional shapes and sizes to suit the diverse characteristics of these products. Of particular significance are the introduction of hollow zinc-aluminum bearing stock, and the availability of zinc alloy machining bar stock for hydraulic applications and for producing prototypes of zinc alloy pressure die castings. In addition to the traditional benefits, continuous casting provides special properties which are important in the application of these bar stock products. The list of successful applications of continuously cast zinc alloy bar stock is growing rapidly, and the market potential for resultant new zinc applications appears to be significant.

Jan 1, 1993

By Rokot M

In a little over three years, Chevron Niugini has built up a team of relatively young, hard working men and women, mostly Papua New Guineans, who spend most of their working days out among people in the Southern Highlands and Gulf Provinces who are directly affected by the Kutubu Petroleum Development Project. These are Land and Community Relations officers, or LACROs. They take on a huge responsibility, not only representing Chevron but also being friend, advisor and negotiator, frequently dispensers of medicines, and agricultural advice and more. When things go well, others get the praise, when things go wrong, LACROs are the martyrs. Just as the geologists who locate the oil, the drillers who find it, the engineers who design the facilities, the construction gangs who build them, the landowners who claim it, and the Government who monitor it, so are the LACROs part of a team.

Jan 1, 1991

The green field discovery of a two million ounce high-grade refractory gold ore deposit in the Indonesian Province of Sulawesi Utara, led Newmont to utilise its proven technical expertise in dry grinding and whole ore roasting to develop a 2000 tonne per day, 160 000 ounce per year operation in this remote and picturesque location.Located at an elevation of 250 in above sea level and ten kilometres to a deep water natural harbour, the hard rock open pit mine, process plant and infrastructure facilities were built to budget at a capital cost of US$132 million. The plant was commissioned with oxide ore, with the first gold poured in March 1996 and with refractory ore in January 1997. The operation rapidly met its production targets because of extensive forward planning and training programs developed for the local workforce. The presence of steep topography, fertile coastal plains, high rainfall, high seismicity of this location led to the decision to dispose of neutralised tailings in deep water off the coast instead of impounding tailings in a dam. This paper describes the development of the project and the challenges in developing a gold operation in a remote location which lacked infrastructure, the steps taken to ensure a smooth commissioning, and the selection of the workforce to operate a technically sophisticated facility.

Jan 1, 1997

By D Fukuda, K Kaneko, R Kudo, J Kodama, Y Fujii, T Sasaki

"Estimation of stress state as well as elastic modulus is important for the prediction of a rock slope deformation in an open pit mine since it can strongly influence the mining-induced deformation of the rock slope. This study applies a method to evaluate regional stress state and Young’s modulus by analysing the mining-induced deformation of ground. The effect of changes in regional strain state due to tectonic plate motion can be accounted for using the proposed method. Mining-induced deformation can manifest itself as changes in ground surface geometry resulting from mining activity. There are three underlying factors that can contribute to the deformation: displacement induced by the effect of gravity displacement induced by the effect of horizontal regional strain incremental change in the horizontal regional strain. The relative displacement arising from the mining excavation at the Torigatayama limestone mine in Japan has been measured by Global Positioning System (GPS). Both the regional stress state and Young’s modulus were estimated by back analysis of the change in distance between GPS stations using a 3D finite element method. It was shown that the reliability of the estimation improved with an increase in displacement due to mining progression. It was also shown that values for Poisson’s ratios of less than 0.10 are reasonable estimates with values for Young’s modulus between about 5?GPa and 10 GPa. The magnitude and direction of the maximum compressive stress in the district surrounding the Torigatayama mine were estimated to be between -6.4 MPa and -4.4 MPa and around N25E respectively.CITATION:Kodama, J, Sasaki, T, Fukuda, D, Kaneko, K, Fujii, Y and Kudo, R, 2014. Estimation of regional stress state and Young’s Modulus of ground at Torigatayama Limestone Mine in Japan, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference, pp 135–142 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 5, 2014

By Vestre J, Kure K, Bergqvist I

Existing practical laboratory tests for comparative strength determination of commercial explosives consist of the lead block test, the ballistic mortar test, the bubble test etc. These tests are carried out in material with quite different properties compared to rock. The theoretical performance potentials of commercial explosives are traditionally described by weight-strength (WS). Some explosive producers use the Langefors formula for weight-strength calculation, where also the gas volume is considered. Neither the theoretical nor the practical methods for determination of explosive performance such as the above, give good enough prediction of fragmentation and heave in rock blasting. For these reasons a project was started for the purpose of finding a small scale test method which predicts how different explosive parameters affect fragmentation and heave. Small scale tests were carried out by using 50 cm cubical blocks, mainly of concrete, but a few also of rock. All blocks were blasted in a steel cylinder with a diameter of 1.2 meters. The velocity of detonation was monitored, and the velocity of fragments was derived from their time of arrival at the steel wall, which was registered by accelerometers. After blasting all fragments were screened. The charge diameter was 22 mm and the amount of explosive 78 grammes, resulting in a specific charge of 0.62 kg/m3. Explosive properties such as energy, gas, VOD and density were systematically changed.The results presented in this paper show how fragmentation and heave systematically change when the explosive properties like energy, gas, VOD and density are systematically changed. The results from the small scale tests are compared to full scale tests carried out in tunnel blasting, and during summer 1990 also in bench blasting.

Jan 1, 1990

By D Wei

Large tonnages of low-grade haematite ores need to be treated every day in China. One of the mineralogical characteristics of these haematite ores is that the grain size of haematite is smaller than that of quartz and is not uniform in the ores. Therefore, a flow sheet consisting of gravity concentration, low-intensity magnetic separation, high-intensity magnetic separation and reverse flotation is mainly used to separate haematite ores in China, to obtain acceptable beneficiation performance and reduce the operating costs. Nowadays, whether based on mineral processing practice or theoretical analysis, the results show that the application of the above-mentioned flow sheet is able to take full advantage of these mineral processing methods and achieves satisfactory benefi ciation of haematite ores. For example, when the iron grade of the haematite ore is about 29 per cent Fe, a concentrate assaying 68 per cent Fe can be obtained and the recovery of iron is over 80 per cent. In the future, research work on the beneficiation of haematite ores should focus on investigating the most feasible particle size for gravity concentration circuit feed so that the operating costs can be reduced and ultimately the separation performance can be improved.

Jul 11, 2011

Lihir Gold Mine is situated in a dormant volcanic caldera on a small island off PNG. Not æextinctÆ but dormant. Current ground temperatures are up to 150 degrees Celsius with active geysers in the workings of the mine, pools of boiling ground water adjacent to low-grade dumps and hydrogen sulphide gas emissions. It is a unique mining environment by world standards. This paper will deal with the following issues encountered and managed by the operation:blasting in hot and reactive ground; management of sulphide gas emissions; disposal at sea of all mining waste rock; one dear to all Australian minerÆs hearts û dealing with landowner groups; and unusual human resource issues.

Jan 1, 1999

By L Mariano

Three selected iron ore samples from the major bedded and channel iron deposits of Western Australia were analysed using a scratch test commonly used in the oil and gas industry. The portable commercial equipment dubbed Wombat cuts a groove on the surface of the sample with a cutter under imposed depth of cut and cutting velocity. The normal and tangential components of the force acting on the cutter are recorded with a high degree of precision (about 1N) at fine spatial resolution of about 20 measurements per millimeter.The intrinsic specific energy inferred from the scratch test measurements is found very well correlated with a classical measure of strength such as the uniaxial compressive strength, for over 300 sedimentary rock samples.The results obtained on the iron ore samples are comparable to those obtained on oil and gas sedimentary rocks. This method could provide an objective and semi-automated measurement of material strength and brittleness in iron ores that can possibly be correlated to the lump to fines ratio.

Jul 11, 2011

By J Rostami, T Afshar, M Sharifzadeh

Accurate estimation of rock load and selection of types of ground reinforcement to match post-failure behaviour of rock mass are important issues to assure tunnel stability. This paper focuses on the main factors affecting rock load to evaluate the capabilities of the existing models for prediction of rock load. Rock mass properties, project features and excavation method, as well as ground conditions and stress condition were found to be the key factors affecting the magnitude of rock load. Field data from tunnels of about 37.5?km driven in several geological structures in non-squeezing ground was used in this study. An in depth statistical analysis was performed on data to find correlations between the input parameters and measured/observed rock load. A weighting system was proposed to obtain the proper contribution of each factor for estimation of rock load in tunnelling through various ground conditions. The new classification system offered predicted values for rock load that were in a good agreement with the actual field measurements. The high disturbance factor (D>0.4) was the prime factor which controlled the rock load. Rock mass quality was the second key factor influencing rock load, which could be estimated by GSI, GSIresidual , especially when combined with tunnel depth.CITATION:Afshar, T, Sharifzadeh, M and Rostami, J, 2014. Estimation of rock load for tunnels with different disturbance factors, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 3–8 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

The organisers of this function have suggested that this presentation should accomplish the following broad goals:set the technical tone for the conference to follow, implying some discussion of the æstate-of-the-artÆ of reserve estimation; and raise some current and common problems or deficiencies in our art in order to be thought provoking. As an engineer it is always easier to raise problems than to solve them with state-of-the-art. Consequently, I have had to limit the extensive list of problems that could have been discussed within this presentation. In regard to the state-of-the-art, this presentation will not be an esoteric discussion of the latest statistical estimation processes, although I intend to challenge those with skills in that area to address some of the thought provoking issues later on. The subtitle of the paper was established after reading an excerpt from æLife on the MississippiÆ by the American humorist Mark Twain in which Twain observed that the Mississippi River had become shorter during his working period on the River due to natural cut-offs and man made channels. Projecting into the future, he calculated that by now, Cairo, Missouri and New Orleans, Louisiana would become a single city with one mayor (the two cities are still separated by some 500 air miles). As a moral to this story Mark Twain observed that one can obtain: æwholesale returns of conjecture out of such a trifling investment of factÆ.

Jan 1, 2000

By M Fuchs

Roadheaders were introduced to mining and tunnelling in the early-1960s. Since this period their main field of application has been for roadway drivages in coal mines and for mineral production, for instance in coal, rocksalt, potash and gypsum mines. Their main field of application in tunnelling is in softer and partly friable rock formations, a suitable area for non-blasting excavation. However, in longer tunnel sections excavators with high ripping forces have replaced roadheaders in many situations. The main arguments against roadheaders have been and still are:a sharp increase in excavation cost with increasing rock strength and increasing abrasivity; and greater risks in conditions which have not been, or could not be, investigated to a sufficient extent. These arguments have, to a great extent, restricted practical roadheader application in production mining and in a lot of æstandardÆ tunnel projects. To address these limitations, factors which could make roadheaders attractive for such conditions and could overcome existing technological difficulties have been investigated. Extension of the economic field of application in hard rock was found to be the most important and the most effective step forward.

Jan 1, 2002

By Voss Smith F, Matters C. W, Slee R. T, Coldham JC, Davies HW, Wallman H. H

The Committee desires to thank the managers of the various mines along the line of lode for their hearty co-operation in its labours. It would also extend thanks to Messrs. J. O. Moulden, Howchin, Twelvetrees, and the West Australian Geological Survey for various information; to Messrs. J. G. Dreyer, S. Pope, T. Read, P. Moncrieff, R. Williams, and W. J. Rose for analyses; and to a number of local gentlemen for advice and help. Professor Skeats, of the Melbourne University, gave much valued assistance in petrology, and Mr. Herbert Lavers kindly undertook the study of the garnets.INTRODUCTIONThe famous Broken Hill lode is situated in a low range of hills, the Barrier Ranges, near the western border of New South Wales. It has been worked since 1884-first for, silver, then for silver and lead, and at present for lead, silver, and zinc. No excuse seems necessary for placing before members even an imperfect report on the geological features of this notable ore deposit, since so little work has been done on the subject as to constitute almost a national reproach. This is the more deplorablesince the evidence laid open by mining operations is destroyed almost as soon as it is exposed, and there exists the real need of a continuous and connected record of geologieal developments.

Jan 1, 1911

By Falbo A, Barbaro M, Esposito MA, Passariello B

Acidic reductive leaching is one of the best known and most widely employed chemical processes for beneficiating minerals of industrial interest. Conventional acidic leaching with sodium dithionite (Na2S2O4), employed to bleach industrial minerals used in the production of ceramics, glassware, paper etc, does not always allow products of high quality to be obtained. In the work reported here two reducing agents, ascorbic acid and oxalic acid, have been employed in a medium acidified by means of sulphuric acid. Continuous systematic tests have been performed on a kaolin sample containing 0.8 per cent Fe2O3, adopting various operating parameters such as, leaching time, temperature and reagent concentration. In each case the total quantity of bi- and trivalent iron dissolved was ascertained. Removal of 80 per cent and 100 per cent of iron with ascorbic and oxalic acid respectively was obtained, while less than one per cent of iron was dissolved in the presence of sulphuric acid only. Products having a very good degree of whiteness (92 - 94 per cent) were obtained, whereas with sodium dithionite the degree of whiteness was in the 85 to 88 per cent range. The best conditions identified were applied to a sample of quartz for the removal of ferric impurities.

Jan 1, 1993

The building is a lofty, well-ventilated one of hardwood frame, with galvanized-iron walls and roof, and consists of five spans running north and south, covering a total length of 236 ft. Each span is composed of nine bays of 1:3-ft. centres, making the total width of the building 117 ft. The refinery is situated conveniently at a distance of 100 yds from the smelters. Through the third span of the building runs a 5-ton electric overhead travelling crane, of a 3-motor type, with a span of 29 ft. The crane runway extends over a railway line, which connects the smelters to the refinery. This crane is llsed for handling bullion, coal, melting kettles, lead pumps, &c. A 3-ton crane of similar type, but with a 50-ft. span, runs through the fifth span of the building and also extends over the railwav line alreadv mentioned. This crane is used to load the soft lead into railway trucks, or to stack lead awaiting shipment in the area covered by the crane's operations.

Jan 1, 1918

By G B. Douglas

Lime-based neutralisation has long been the remediation treatment of choice for acidic mine pit waters. While suited to the attenuation of acidity, lime-based neutralisation may be difficult to implement efficiently due to variation in quality and the partial loss of neutralisation efficiency due to armouring. Large volumes of gypsum-bearing sludge may also require mechanical dewatering and transfer to final voids prior to resumption of in-pit mining or closure. Thus, operational costs may be substantially higher than primary neutralisation alone. Lime production also results in large greenhouse gas (CO2) emissions.Hydrotalcites (HT) are a class of Mg-Al layered double hydroxide minerals with the composition Mg6Al2(CO3 )(OH)16.4H2O. A range of other divalent and trivalent cations may also readily substitute for Mg (eg Cu, Ni, Pb, Zn), Al (eg Fe, La, Ce) and metalloids/oxyanions (SeO42-, AsO43 -/CrO42 -, MnO4-) for CO3 into the hydrotalcite structure. A common feature of acid mine pit waters, often overlooked in assessment of potential remediation options, is the frequent predominance of divalent and trivalent cations as a consequence of partial decomposition of both ore and gangue minerals during in-pit wall rock leaching. Thus, given the presence of substantial divalent and trivalent cations in acidic mine pit waters, an opportunity exists to exploit and in effect work harmoniously with the prevailing pit water composition to form a polymetallic hydrotalcite.The utility of hydrotalcites in the remediation of acidic mine pit waters lies in their ability to incorporate a wide range of contaminants; instantaneous formation, often in a single step; simple post-treatment solute composition; rapid settling; low sludge volume; and the potential to form ore-grade precipitates potentially amendable to reprocessing to (partially) recover remediation costs. Examples of hydrotalcite formation as a method to remediate contaminated acidic mine pit waters at laboratory-scale to full-scale will be presented.CITATION:Douglas, G B, 2015. Whither lime? In situ hydrotalcite precipitation as a method of remediation for acidic mine lakes, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 97–104 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

By Hocking G

For some underground structures, the use of the plane strain assumption in stress analyses may not be justified. The finite element method and photoelasticity have been used to obtain complete 3-D solutions, but, for various reasons, neither method has found universal use. The boundary integral equation method (B.I.E.M.) can be more efficient and economical than the finite element method for 3-D problems involving large volume to surface area ratios. A B.I.E.M. program developed for calculating stresses and deformations in infinite elastic media has been used to determine the 3-D distributions of stress around T- and Y- junctions of circular tunnels in stress fields in which the ratios of horizontal to vertical stress are 0, 0.33, 1.0 and 2.0. For the T- junction considered,stress concentrations at the intersection are approximately twice the plane strain values. Except where horizontal field stresses are high, the stresses in both tunnels approximate the plane strain values at about two tunnel diameters from the point of intersection of the tunnel centre lines. The stresses in the two branches reach those for the corresponding plane strain, two parallel tunnel case two diameters from the point of intersection of thq inner tunnel walls. Very high stress concentra- tions occur in the pillar of rock between the inner tunnel walls near the point of intersection.

Jan 1, 1976