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By S Q. Liu, E Kozan

This paper proposes a new multiresource multistage scheduling problem for optimising the open pit drilling, blasting and excavating operations under equipment capacity constraints. The flow process is analysed based on the real-life data from an Australian iron ore mine site. The objective of the model is to maximise the throughput and minimise the total idle times of equipment at each stage. The following comprehensive mining attributes and constraints have been considered: types of equipment; operating capacities of equipment; ready times of equipment; speeds of equipment; block-sequence-dependent movement times of equipment; equipment-assignment-dependent operation times of blocks; distances between each pair of blocks; due windows of blocks; material properties of blocks; swell factors of blocks; and slope requirements of blocks. It is formulated by mixed integer programming and solved by ILOG-CPLEX optimiser. The proposed model is validated with extensive computational experiments to improve mine production efficiency at the operational level. The model also provides an intelligent decision support tool to account for the availability and usage of equipment units for drilling, blasting and excavating stages.CITATION:Kozan, E and Liu, S Q, 2014. An Open pit multistage mine production scheduling model for drilling, blasting and excavating operations, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 329–334 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

Good morning ladies and gentlemen, and may I extend a particularly warm welcome to our shores to those of you who have travelled from overseas to attend this conference. I trust that you will find your visit to New Zealand both rewarding and enjoyable.   This is now my fourth appearance at a New Zealand minerals conference, the second of which has been jointly co-hosted by AusIMM and Crown Minerals. Since taking on the role of Associate Minister of Energy, I have had the opportunity to meet most of the industry players, and to visit a good number of the major mining operations. Through all of this I have become increasingly aware of not only how dynamic the minerals and coal industry is but also the array of factors that affect investment decisions in this business. Many of these factors, such as commodity prices and availability of investment funds, are determined primarily on the international stage. Others however, such as the allocation, regulatory and the fiscal regimes for minerals, are closer to home and are directly influenced by government policy decisions. I will talk more on what the government proposes in this area shortly.   But first, I would like to commend you all on your industryÆs continuing contribution to New Zealand Æs economy. 2004 has seen New Zealand Æs mineral and coal output top $1 billion for the second consecutive year. To put this achievement in perspective, it represents a staggering 47 per cent increase over the national output value recorded just five years ago. Notable contributions over the year came from gold which increased production to 10.2 tonnes (up nine per cent), ironsand production at 2.3 Mt (a 20 per cent increase), and industrial rocks and building stones (up six per cent) with rock for building, cement and roading showing significant rises on the back of strong regional growth and infrastructure development. Many regions, in particular Auckland, Bay of Plenty, Wellington and Southland, recorded significant increased regional activity with supply often struggling to meet demand. By contrast the coal sector had a relatively steady year with production remaining stable at just over five million tonnes for the second year running. Coal exports however are now consistently exceeding two million tonnes annually, generating export earnings of over $200 million, and could well be higher with rail capacity improvements. Many countries throughout the world are now importing our high quality bituminous coal for steel manufacturing and other industrial uses.

Jan 1, 2005

The Great lady gold deposit presented the challenge of providing a new grade control system for an usual type of orebody in the Eastern Goldfields. Mineralisation occurs as secondary enrichment about a quartz sand - granite saprolite contact 30m below surface. The ore horizon, which averaged 2.5m thickness, was near-horizontally disposed in contrast to the typical steeply dipping, shear hosted deposits of the region. A trial mining operation was undertaken on the richest, most continuous portion of the deposit to test the economic viability of this type of orebody. Controlling and minimising vertical ore dilution was considered crucial to the profitability of the operation.An understanding of the grade distribution combined with the practicalities of mining produced a grade control system which allowed for the mining of 1/2rn composited grades on level lm benches. Ore mining was combined with strict monitoring of levels, truck destinations and ore boundaries. Ore reconciliation results showed this system to be effective.

Jan 1, 1990

This paper discusses the recently com- pleted TBM-driven pressure tunnel at the Sand Bar Hydroelectric Power Project. The Sand Bar Project is a diversion scheme situated on the middle fork of the Stanislaus River in the Western Sierra Nevada, California, U.S.A. As part of the project, a 5.6 km long and 3.71 m diameter unlined pressure tunnel was bored by a Jarva TBM at the average rate of .37.5 m/ day. This report deals with construction aspects of the tunnel, including TBM performance, lining design, and remedial support measures. Correlations between TBM performance, geologic conditions, and rock properities are made, and the Contractor's mode of operations are discussed. Advance rate prediction, and the impact of these excellent advance rates attainable in hard rock using the new machines are discussed.

Jan 1, 1987

The purpose of this paper is to list by tabulation and flow sheet, the operating equipment and installations in use at Rosebery, and to refer to particular items which may be of interest for purposes of comparison, or because they possess some unusual feature. The general perspective has been taken from the viewpoint of operating and maintenance experience.The sequence begins with ore breaking and transport and proceeds through milling operations. The paper is in two sections, first, mechanical equipment, second, electrical equipment. A brief outline of a scheme for using gravel wash for stope filling, which is in course of installation, has also been given.

Jan 1, 1949

By M Grossi, G Baiden

This paper describes a new mine backfill method based on a newly invented binder with several years of test results from laboratory and onsite applications. The new binder has several advantages over traditional Portland and slag cement binders. One tonne of the new binder can replace two to three tonne of Portland cement when used to consolidate backfill and can result in the same compressive strength within seven days. When comparing backfill slurries of the same pulp density, the new binder attains more volume of in-place backfill mass than Portland cement because of the high crystallisation of water, resulting in tightly filled stopes. The crystallisation of the water provides for less or no dewatering in the backfill stope and easier transportation of the backfill slurry. Pastefill performance can be achieved by using pulp densities typical of a hydraulic backfill and the new binder, all the while transporting with the same ease of hydraulic fill.

Jan 1, 1998

North Flinders Mines Limited (N.F.M.) is an Australian-owned mineral exploration and mining company based in South Australia. In the 1970's it researched the prospectiveness of the Tanami (central western region of the N.T.) for the identification of possible economic gold deposits. Having outlined the potential for such a deposit at The Granites (550 km. N.W. of Alice Springs), it marked out and in 1975 applied for the grant of eleven gold mining leases (G.M.L.'s) under the provisions of the then Mining Ordinance. This application was deferred by the Commonwealth Government during the time of the Aboriginal Land Rights Commission (Woodward), subsequent enactment of legislation and land claims. In 1980, the Walpiri and Kartangarurra-Kurintji land claim encompassing the G.M.L.'s, became Aboriginal land. It therefore became necessary for N.F.M. to negotiate a mining agreement with the Central Land Council (C.L.C.) represent- ing the Traditional Owners, before the G.M.L.'s could be granted. In August 1983, the C.L.C. and N.F.M. concluded an agreement to enable the grant of mining interests necessary for the devel- opment of The Granites Gold Project. In several ways this agreement is unique in That:

Jan 1, 1984

By R Burgess-Limerick, J Haight

A review of mining automation experiences was undertaken on behalf of the National Institute for Occupational Safety and Health (NIOSH). The research included a review of literature and guidance materials; analysis of automation related incidents and visits to surface and underground mines in Australia, Brazil, Chile, South Africa, Sweden and the USA.

Apr 16, 2024

By Pinter R

Several major routes connecting Northern and Southern Europe or Asia run through Austria. These highways have to surmount the alpine range which traverses Austria from west to east. In order to ensure safe driving conditions even in winter, tunnels, at times quite long ones, are necessary. Austria now has tunnels totalling 160 km in length. These tunnels are either already in use or just about completed. The Plabutsch tunnel near Graz will be one of the longest tunnels in the world: approximately 10 kilometers in length. It will be put into operation in the summer of 1987. Before construction could begin, soil and rock conditions had to be investigated by means of a test tunnel. Afterwards, excavation was begun to the full 100 m' cross section. The new Austrian tunnelling method with conventional blasting was used for the major part of the tunnel. It was necessary to have such a large tunnel cross section because a fully transverse ventilation system is installed for environmental reasons. In order to avoid air pollution from the tunnel, exhaust fumes are not allowed to escape from the tunnel portals but from two shafts, each with a diameter of 8.5 m. In this way, exhaust fumes must rise 90 meters or 240 meters before they reach the open air and will thus not affect the city. The ventilation system influences the size of the excavation, and especially the size of the ventilation caverns and the air shafts. All these factors directly influence construction and maintenance costs, and an economical optimisation leads to the appropriate dimensions for the excavation.

Jan 1, 1987

By Theophili CN, Kapenis AP

Seismic tomographic imaging has been applied to determine the blast induced damage zones in bauxite pillars in underground mining. At the retreating stage, when pillar dimensions are reduced from 8 x 8 m to approximately 5 x 5 m, the' seismic tomographies reveal, through measurements of the P-wave velocities which is a measure of the degree of fracturation of the pillar rock mass, the presence of three zones within each pillar. In the external zone, where velocities recorded are below 750 m/s. extensive pillar damage occurs which is attributed to both the growth and coalescence of pre-existing cracks and even the creation of new cracks in the rock mass. This effect is in agreement with literature, when considering the peak particle velocity as a criterion for rock failure in tunnels. In the intermediate zone, where velocities range between 7S0-1000 m/s, damage to a much lesser extent occurs which is due mostly to growth of pre-existing cracks and widening of their apertures. The inner zone, where velocities exceed 1000 m/s, is considered to be unaffected by blasting. Simple remedial measures of low cost, which are based on blasting mechanics are proposed to minimise the blast induced damage zone and consequently the transition zone.

Jan 1, 1995

By P Gomez, R Baumgartner, G Escobar

"The Cerro Corona mine consists of a Cu-Au porphyry deposit located in the Andes of northern Peru. The deposit comprises a typical Cu-Au multiphase porphyry mineralisation that has been overprinted by an epithermal event. This has generated a complex pattern of argillic alteration facies, which was accompanied by a locally structural-controlled Au-Cu mineralisation with the presence of gold and limited Cu sulfides and sulfosalts. These features, along with the porphyry-style mineralisation, produced a multifaceted occurrence of gold.Since the beginning of operations at Cerro Corona in 2008 there has been a continuous improvement of the geological and mineralogical knowledge. All mineralogical studies have mainly focused on host rock types and, to a lesser extent, alteration minerals, but little work has been done on the mineralisation itself. As a consequence, limited mineralogical information was available for use in the process optimisation initiatives.In the last two years, a series of mineralogical characterisation studies were undertaken with two main goals. First, to gain an understanding of the mineralisation genesis and second, to obtain a detailed characterisation of copper and gold minerals to support ongoing process optimisation. The first goal was achieved by conventional optical microscopy while the second required electronic microscopy and other microanalyses due to the necessity of quantifying several minerals of interest for the processing.The results were used to refine pre-existing geometallurgical domains, explain copper and gold losses in the flotation process and to some extent, improve copper and gold recoveries. The mineralogical characterisation is an ongoing work. Mineralogy provides the basis for any optimisation exercise since it looks in detail at the material to be treated and therefore, should be part of all geometallurgical programs.CITATION:Baumgartner, R, Gomez, P and Escobar, G, 2016. Comprehensive Mineralogical Characterisation at the Cerro Corona Cu-Au Porphyry Mine – the Fundamental Key for Geometallurgical Applications, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 221–230 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By J Gould, T Elkington

Mine operation strategies are commonly optimised with a net present value (NPV) maximisation objective. There are well known properties of a typical mining project optimised for NPV, including high production rates and declining cut-off grade schedules. In practice, however, frequently there are operations that diverge from such NPV-maximising properties. Although a range of reasons for this can be at play, one possible explanation is that operators intuitively adjust their strategies to compensate for the flaws inherent to NPV maximisation. In particular, NPV analysis does not reflect the benefits of managerial flexibility inherent in a mining plan. Real options valuation (ROV) is an alternative approach that addresses this issue. We compare the properties of NPV and ROV optimisation solutions generated for the same scenario. Our simple case study demonstrates that the presence of real operating options in the optimisation model not only entails increased project value as expected, but also tends to encourage lower processing capacity (with lower associated capital cost), higher cut-off grades and greater use of stockpiles.CITATION:Elkington, T and Gould, J, 2012. Real option value optimisation, in Proceedings Project Evaluation 2012 , pp 35-40 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 24, 2012

By Y Li, Z Fu, D J. Williams, E Topal

Mine waste rock is unavoidable in the recovery of ore by open pit mining methods. Effective management of waste rock movement covers the removal and placement of the waste rock, generally in a surface dump in the most cost-effective way while satisfying the long-term environmental expectations. Since the 1960s, there has been significant research carried out into planning of ore movement from open pit mines such that the overall net present value (NPV) of the project can be maximised. Currently, several software packages are available to achieve this task as a common practice within the mining industry. However, planning of mine waste rock movement is still achieved manually, as the available software does not consider optimal waste rock movement and dump design. This paper describes a tool to optimise waste rock placement, which minimises the haulage cost while creating environmentally friendly waste rock dumps through selective placement and encapsulation of the reactive waste rock in the dump. The embedded methodology in this tool has been developed based on the mixed integer programming (MIP) modelling technique to optimise the waste rock movement. The methodology provides an easily-manipulated and fully-automatic tool for professionals to complete waste rock dump scheduling in four main steps: data input, model construction, model computation and solution retrieval. The application of the new tool into a real case project in this paper shows that it can determine economically and environmentally optimised waste rock dump schedules in an acceptable time frame.CITATION:Fu, Z, Li, Y, Topal, E and Williams, D J, 2015. A new tool for optimisation of mine waste management in potential acid forming conditions, in Proceedings Tailings and Mine Waste Management for the 21st Century, pp 333–342 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

By J M. Santini, I C. A Streimann

Arsenic is a naturally occurring element in the environment and is toxic to biological systems. Arsenic can exist in the environment in the following redox states, arsenite (+3), arsenate (+5), arsine (-3) and elemental (0) (Oremland and Stolz, 2003). Arsenic is released into the environment by natural and anthropogenic activities such as rock weathering and ore mining, respectively. Such activities result in the release of the soluble inorganic arsenic oxyanions, arsenite and arsenate. The redox state of arsenic in the environment is influenced by a number of factors including, redox potential, pH and microorganisms (Irgolic et al, 1977; Genc-Fuhrman, Tjell and McConchie, 2004). Recently, the ability of microorganisms to influence the cycling of arsenic in the environment has attracted much attention. Microorganisms that can oxidise arsenite and reduce arsenate have been isolated and the mechanisms of arsenic metabolism are currently being investigated. The differences between arsenic resistance and arsenic metabolism are being revealed. The role of microorganisms in the release of arsenic into the environment is of particular importance with arsenic contamination of waters causing the death of millions of people worldwide, due to the consumption of contaminated water (Vasken Aposhian et al, 2003; Islam et al, 2004).

Jan 1, 2004

Tomago sandbeds is an unconfined coastal aquifer located 20km. north of Newcastle in New South Wales, Australia. These sandbeds extend over an area of about 130km. The average aquifer depth is about 20m. with a mean transmissivity of about 400sq.m/day and a specific yield of about 0.2. The city of Newcastle and surrounding areas derive water from Tomago for potable purposes. The average extraction being about 50 ML/day. The iron value of the ground water varies between 5 and 15mg/1. This iron is removed by a conventional water treatment plant using Alum. The aquifer whilst principally quartzose also contains deposits of heavy minerals like rutile, zircon, ilmenite, etc., The mineral sand mining has been in progress at Tomago since 1972. Mining is carried out in a con- structed pond with a water depth of about 5m. on which is floated a suction cutter dredge that moves across the front of the pond using a water jet to entrain the soil from the ground surface to the bottom of the mineralised zone. Effect of mineral sand mining on ground water quality, particularly iron, was the subject of intensive investigations undertaken at Tomago since 1970. The effect on water quality was studied by collecting and analysing water samples from network of observation wells established during the period of mining. Water samples were collected about 4-5 years prior to mining and analysed for iron, sulphate, chloride, pH, etc., After mining the observation wells were re-established at the same locations and water samples were collected and analysed for at least 5 years after mining. Water samples collected from majority of the observation wells indicate an increase in iron levels. The level of increase is very site specific. The increase in iron is also

Jan 1, 1987

By Merwin RA

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

Jan 1, 1993

By J Addai-Mensah, W Skinner, C Kelsey, J R. Kelly, E Baawuah

Comminution continues to be the most capital-intensive unit operation in mineral processing. The fundamental purpose of comminution is to liberate the valuable minerals so that they can be economically concentrated into saleable products. Declining ore quality characterised by lower grade and increased complexity requires significant energy consumption for comminution. Low-grade magnetite ores are typically fine-grained and require fine to ultra-fine grinding (P80 ~ 30 - 40 µm) to enhance its liberation from the typically siliceous gangue matrix. Historically, this has been achieved using multi-stage crushing and grinding technologies, which require high energy consumption with low energy efficiency. This motivated innovations in energy efficient technologies for comminution. Such technology has been developed in the IMPTEC super-fine crusher. It is an innovative, dry (with the potential to be operated wet), media-free, energy efficient crusher that can to reduce 10 mm feed particles to 19 – 30 µm with very low recycle loads. In this study, the mineralogical and physicochemical characteristics of crushed magnetite ore using the IMPTEC super-fine crusher have been investigated in comparison with those of rod milling. The super-fine crusher generated higher liberated magnetite minerals in the – 300 + 212 µm and < 45 µm size fractions compared to rod mill. Both comminution devices generated large low-grade hematite and goethite middlings. However, the rod mill produced higher locked/unliberated hematite and goethite compared to that of the super-fine crusher. Quartz mineral had the highest liberation irrespective of the comminution device used. The super-fine crusher generated higher entrapment of other minerals within the silica matrix compared to the rod mill. The breakage mechanism of the super-fine crusher which is predominantly through high compression with shear, generated improved mineral liberation in the coarse size fractions compared to the predominant abrasion and attrition breakage mechanisms of rod milling. The higher mineral liberation generated by the rod mill is potentially due to the prolonged batch milling of the ore compared to the single-pass open circuit of the super-fine crusher.CITATION:Baawuah, E, Kelsey, C, Kelly, J R, Addai-Mensah, J and Skinner, W, 2018. Mineral liberation studies of IMPTEC super-fine crusher – 130 crushed product, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 313–326 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By Wooltorton B

Highwall failures in surface coal mines in Queensland occur as circular slips through weak and weathered material, or as bilinear slides on sub-horizontal surfaces and steeply dipping joints. Weak horizontal planes occur in the Permian-Tertiary unconformity or on bedding surfaces within the Permian Coal Measures. Sub-vertical movements occur along rock joints and tension cracks induced by stress relaxation after excavation. Blasting also introduces new fractures and causes movement along existing rock discontinuities. Critical factors for stability include the dip direction of potential failure surfaces, shear strength of the rocks, damage due to blasting prior to highwall excavation, groundwater conditions, the type and performance of clays on shear surfaces, and pit geometry.

Jan 1, 1981

ICI Australia has been developing PC-based software to assist the blast engineer to design and monitor open pit blasts. The scope of this software differs significantly from commercially available mine design packages.The software is designed for routine use in a normal production environment. The system enables the engineer to produce practical documents which include: a drilling plan, a loading sheet, a hook-up diagram, an inventory of explosives and auxiliary items, and other data on the blast such as tonnages and powder factors.

Jan 1, 1992

By G J. Keyter, P J. Terbrugge, Yu Xianb

There has been disappointingly little development in the understanding of the behaviour of rock slopes in open pit mines over the past 30 years. The lack of development in general, and of robust, standardised approaches in particular, are surprising in view of the æultraÆ deep open pit mines that are being developed to depths in excess of 1000 m. Research has recently been carried out into the occurrence of zones of extension strain in open pit slopes. This showed that very large zones of extension strain can occur, and this finding represents a significant new aspect in slope stability that has not been considered before. The greatest magnitudes of extension strain occur near the toe of the slope, either in the slope itself, or in the floor of the pit. Results of the research will be presented for different slope heights, slope angles and horizontal to vertical in situ stress ratios. The magnitudes of the strains are considered to be large enough to result in fracturing of intact rock, and the fracture orientations predicted are adverse for slope stability. Fracturing that is extension in nature is common in competent, brittle rocks and often develops with some violence and little or no warning, producing easily measurable seismicity. In the slope situation, the expected physical manifestation of this behaviour would be popping off of rock slabs and plates of rock from slope surfaces and popping up of the pit floor, as well as the formation of new fractures within the rock mass. Such behaviour may cause overall slope failure, or may initiate failure, which may then be driven to overall slope failure by other influencing factors or combinations of factors. In addition to instability resulting from the fracture surfaces themselves, all induced fracture surfaces could interact with natural geological structures to facilitate formation of a significant failure surface. Case studies of slope failure in two open pits will be described. In both cases failure occurred æsuddenlyÆ after very limited amounts of deformation. In the first, the slope crest moved suddenly upwards and backwards over a length of more than 200 m, with associated instability. In the second, the horizontal displacement of the slope face was almost an order of magnitude greater than the vertical displacement and occurred æsuddenlyÆ. A recently installed seismic system is detecting events in a significant zone behind the slope face. Both pits were in the 200 m to 300 m depth range at the time of the occurrences.

Jan 1, 2003