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By G Chitumbura

Raise boring is a critical aspect of mining at Xstrata Copper’s Mount Isa Copper Operations (MICO). MICO’s internal raise boring department regularly develops ventilation rises, orepasses and stope cut-off rises and reams approximately 2500 m per annum. Developed, trialled and implemented as standard practice over the past two years, procedural changes in constructing the raise bore machine’s foundations have significantly reduced operator exposure to raise boring’s inherent risks of working around open holes and manual handling. An additional cost benefit of this newly-adopted procedure is derived from reducing the likelihood of damaging the machine while de-rigging.When conforming to standard industry raise boring practices, exposure to an open hole begins when the reamer breaks through the concrete pad and ends when it is removed from the hole – a process which, depending on the size of the hole and the raise boring machine, can take up to three days to complete. Although wearing fall restraint equipment, operators working on and around the raise bore machine during de-rigging are continually exposed to the risk of falling from heights. In contrast, MICO’s newly-developed and successfully-implemented presink raise boring system reduces this exposure to a maximum of four hours, regardless of hole size. Exposure to manual handling hazards is also substantially reduced as the presink procedure eliminates manual placement of a 100 kg drill bit under the machine to commence pilot-hole drilling. Outcomes of implementing the presink System at MICO have been so beneficial that it is now standard procedure for all reaming in excess of 1 m diameters.

Mar 21, 2011

By R H. Sibson

The gold province of Otago occupies an area of upwarped basement, the Otago Schist, comprising predominantly quartzofeldspathic and volcanogenic metasediments. This assemblage is the product of collisional tectonic deformation and associated metamorphism, mainly to lower greenschist facies, during the Rangitata Orogeny (200-100 Ma). Historically this region has produced 240 tonnes of gold, 4% (10 t.) of which was from the mining of Cretaceous goldquartz mineralised vein systems. Auriferous vein systems in the Otago Schist are mainly hosted within NW trending normal fault-fracture arrays, however NW trending reverse fault-hosted vein systems also occur. We propose that the Late Cretaceous-mid Tertiary Otago Schist structure represents a regional anticlinorium containing flexural folds of at least two wavelengths. The anticlinorium structure has been quantified by determining variations in angular discordance between schistosity and the Otago Peneplain, a Late Cretaceous-mid Tertiary erosion surface covering most of the Otago district. A structural model for the evolution of the post-collisional anticlinorium requires the cooling surficial zone (carapace) of a retrograding metamorphic belt to behave as an elastic lid. Erosion of topographic load on the carapace drove isostatic uplift, which was greatest in the tectonically thickened core of the orogen. In this way differential uplift produced flexural deformation in the elastic carapace, expressed as a large scale arching of the orogenic belt. Flexure created tangential longitudinal strains in the outer-arc, leading to extension and the formation of mineralised normal faults. These structures are separated by a neutral surface from shortening and associated mineralised reverse faults in the inner-arc. Our structural model predicts that the distribution of auriferous lodes should be localised about zones of maximum flexural curvature, where the tangential longitudinal strains are highest. As a result, NW-SE hinge regions separating schistosity dip domains in the Otago gold province may have new found significance as potential exploration targets.

Jan 1, 1995

By Butters S. E, Deslandes J. V

The selection of loading and haulage equipment in a proposed or oper- ating mine is vital in ensuring the cost effective achievement of produc- tion targets. To assist in the evaluation of different haulage systems, a truck haulage simulation model has been developed at BHP Melbourne Research Laboratories. The operation of the model is described and exam- ples of an actual application at Mt. Whaleback Mine is presented.

Jan 1, 1989

By B Davis, M Wallace, J Stewart, C F Burrett, J B. Cannell

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Sepon district in Lao PDR contains 1.8 Mt of JORC (2012) compliant contained Cu resources in addition to >4.5 Moz of Carlin-like Au in a Palaeozoic sedimentary package. The Cu deposits are proximal to an EW lineament of Permian rhyodacite porphyry (RDP) intrusive centres that are characterised by intense barren quartz stockworks. The Khanong deposit (42 Mt at 3.0 per cent Cu mineral inventory) is a carbonate replacement intermediate sulfidation deposit verging on a high sulfidation environment, where abundant pyrite, copper sulfides (chalcopyrite, bornite, trace enargite), copper sulfosalts (including tennantite – tetrahedrite, colusite), and base metal sulfides (sphalerite and galena) have replaced low dipping dolomite and limestone layers, forming a manto-style orebody fed by steep dipping intensely silica-pyrite altered structures. The Thengkham deposits (54 Mt at 1.5 per cent Cu) are composed of prograde skarns (garnet, clinopyroxene) and mineralised retrograde skarns (chlorite, magnetite, hematite, epidote, sericite, talc, serpentine, carbonates, sulfides) which are irregularly and semi-continuously distributed around an elongate 4 km long intrusive centre. Thengkham and Khanong have been strongly supergene enriched, forming secondary chalcocite breccias and exotic malachite zones.The Carlin-like Au deposits display a range of stratigraphic and structural controls and lie outboard of the Cu deposits. Similar structural controls, alteration assemblages and trace mineralogies suggest that gold and copper mineralisation are temporally and genetically related. It is hypothesised that the differences in style of Cu and Au deposits across the Sepon district are related primarily to palaeodepth and proximity to the intrusive centres.CITATION:Cannell, J B, Stewart, J, Williams, P, Wallace, M, Burrett, C F and Davis, B, 2015. The Sepon copper deposits (Laos) and their relation to Carlin-like gold mineralisation, in Proceedings PACRIM 2015 Congress, pp 399–408 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By S Dykes, R J. McCarthy, B Klein

There is growing interest in the mining industry on the application of ore sorting. While many are familiar with particle sorting, including the limitations that technology presents (e.g. throughput), bulk sorting, with its higher throughput potential, is less understood. Despite the potential to sort at higher throughputs, few operations have adopted bulk sorting processes, certainly not at large scale. It is suggested that the inability to reliably predict outcomes from bulk sorting may be limiting its adoption in mining projects. Consequently, an evaluation approach for bulk ore sorting has been developed such that mass pulls and grade upgrades can be predicted in the context of a mining study. The approach allows for evaluation of drill core assays and application of the consequently derived heterogeneity relationships to the block model for estimation of sorting outcomes. These processes were applied to conveyor-based bulk sorting for the CuMo project in Idaho, USA and are described in this paper.

Nov 10, 2020

By A Baensch, E Grimsley

Eloise Copper Mine is situated 56 km east-southeast of Cloncurry, Queensland, Australia. The deposit was discovered by BHP Minerals in 1986 during follow up diamond drilling of EM anomalies associated with major aeromagnetic anomalies. The deposit is overlain by 60 m of Mesozoic cover. Amalg Resources NL commenced mining during 1995 by means of decline access and long hole-stoping. The total mineral resource comprised 1.77 million tonnes at 4.10 per cent Cu as at the end of June 2003. Proved and probable reserves are 930 000 tonnes at 3.97 per cent Cu. Mineralisation is hosted within a strongly foliated Proterozoic meta-sedimentary sequence comprising arenites and schists. The metasediment sequence also contains a coarse-grained amphibolite body possibly representing an early intrusion of gabbroic composition. Economic mineralisation characteristically occurs as a number of steeply plunging lenticular bodies with strike lengths of between 100 and 200 m and maximum widths approaching 25 m. The principal orebody, the Levuka (B) Lode, displays a down plunge extension exceeding 1000 m and is open at depth. Ore mineralogy is almost exclusively chalcopyrite with the principal gangue phases consisting of pyrrhotite + quartz + carbonate. A biotite + hornblende + magnetite assemblage represents locally intense mafic alteration of the metasedimentary host sequence. Magnetite is present in variable amounts and may be locally significant in some of the smaller satellite orebodies. Within the orebodies the sulfides display a range of textures from massive through to vein like. Sulfides commonly display brecciated textures at a range of scales. Post-mineralisation faulting has severely dislocated the orebodies, resulting in a complex arrangement of fault bounded ore blocks. These faults display considerable variability in regard to strike, dip and amount and direction of throw. A recent review of the fault system by means of large-scale structure underground mapping, re-interpretation of drill core and 3D modelling has led to a significant improvement in the understanding of these structures. A significant upgrade of the geological database has accompanied the structural review. The overall improved understanding has aided the mine design processes with particular regard to decline and access development and pillar location. This has also impacted on the design of drilling programs and exploration for additional satellite ore zones.

Jan 1, 2003

In any open pit mine some slope instability may be expected. This can range from small scale sliding on individual benches to large scale overall slope failure. This paper presents two case histories which illustrate how mining has successfully continued despite major pit instability. The common threads in each of these are listed below. 1. The recognition of the type and nature of movement (either regressive or progressive). 2. The successful application of simple monitoring techniques to minimise the potential impact on the mining operation, and 3. The management of the waste and ore excavation to avoid potentially damaging and costly situations.

Jan 1, 1986

Mineralisation was identified at Gladstone Hill as far back as the late 1870s-early 1880s, shortly after the initial discovery of mineralisation at what is now the Martha Mine. Indeed, early recovery problems associated with the Martha mineralisation led to the preferred development of ore bodies within what is now the Union Hill Joint Venture tenement; ore bodies such as Silverton, Amaranth, and Union to name a few. Gladstone Hill forms the basis of the Union Hill Joint Venture, a 50:50 joint venture managed by Au-Ag Resources Ltd (a fully owned subsidiary of Otter Gold Mines Ltd), and Welcome Gold Mines Ltd (a fully owned subsidiary of the Normandy Group). The joint venture participants also operate the adjacent Martha Mine. Mineralisation of Gladstone Hill, as with mineralisation at the adjacent Martha Mine, has been interpreted as a low sulphidation epithermal Ag-Au system hosted within hydrothermally altered andesites of the lower Coromandel Group. Drilling in recent years has successfully identified extensive mineralisation associated with a number of vein sets throughout the tenement including the Gladstone Vein set, the Moonlight Lode and more recently along a north-easterly trend towards the historic Favona workings. A wide range of vein styles is apparent, ranging in character from thin stock works to broader lode-style banded chalcedonic to cherty quartz and have been interpreted as representing multiple phases of emplacement. At shallower levels mineralisation is often hosted by vein clasts within vent breccias. Visible gold is rare, with mineralisation generally associated with very fine-grained pyrite, arsenopyrite and minor electrum. Percentage levels of combined sphalerite-galena-(+/- chalcopyrite) have been intersected at depth however these have been gold poor to date. The potential for the Gladstone Hill area remains to be clearly defined as drilling to date has yet to close off mineralisation both along strike and down dip. If further drilling is successful, the joint venture partners believe Gladstone Hill could contribute significantly to the economic future of current operations.

Jan 1, 2000

By S Bandopadhyay

The seasonal fluctuations of the dust content in Arctic mine environments and the environmental variables affecting the intensity of dust production are qualitatively well known, but quantitative models that allow simulation and prediction of dust generation and the effects of engineering control of thermal regime on the mine environment are still non-existent. In Arctic mines, the migration of moisture in the surrounding rock mass releases fine dust by freeing it from the ice matrix allowing it to escape into mine airway. The migration of moisture is the direct cause for the production of mine dust and heat is the primary driving force. This paper examins the heat and moisture exchange between the ventilation air and the surrounding rock mass in frozen ground, placer mines in the Arctic. Based on the simulated results of a coupled heat and mass transfer problem with phase change, methods of dust control have been identified for mines in the Arctic.

Jan 1, 2005

By Rosenblatt M, Gilroy J. A C Cunningham C V B

Vaal Reefs Exploration and Mining Company Limited operates one of the largest producing gold mines in the world. The annual production of 76 tons of gold from 12 million tons of ore treated is obtained mainly from underground sources. Daily some 6.6 km of stope face is blasted and 41 tons of explosives is used to break the rock. The mine employs 45 000 men of whom 35 000 work underground. The company operates nine large vertical shaft systems of which seven extend more than 2000 m below surface and an eighth, currently being sunk, will bottom at 3700 m below surface.

Jan 1, 1995

By M Akbarpour, M Osanloo

In mining industries, materials handling costs represent a significant component of the operational cost. A variety of methods have been applied in surface mine equipment selection in order to select the suitable loading system with the lowest loading operation cost. These are queuing theory, bunching theory, linear programming and genetic algorithm. Among them, genetic algorithm is a simple method and applied for preliminary selection of the loading system. In this study, gathering information from anomaly No 2 of Gol-e-Gohar iron mine of Iran, loading system (number and its capacity) has been optimised by genetic algorithm. The study results showed that two shovels 8.25 m3 are required for the removal of 60 million tonnes of overburden. After removal overburden, these two shovels contribute to the extraction of 42 million tonnes of ore with a stripping ratio of 1:1.

Jan 1, 2007

The Regional Development Council has initiated a project that aims to find better ways for further investment by extractive industry companies in sustainable regional and community futures. It will be undertaken through collaborative actions that bring together the resources of private and public sector stakeholders in regional Western Australia.   The broad objectives of the project are to: describe and analyse the current situation with respect to the impediments to regional communities being more self sustaining, assess the effectiveness of the current and possible future levels of investment by extractive industry companies in the sustainable development of communities in regional Western Australia, identify and demonstrate collaborative ways in which extractive industry companies in Australia and other countries can play an enhanced role in sustainable regional and community sustainability through strategic engagement and investment; and confirm the effectiveness of the collaborative measures in delivering sustainable outcomes for regional communities by way of attracting and retaining populations and enterprises in Australia and similar environments.

Jun 1, 2010

By D Crequer

A Peer Review Panel for the Golden Cross Mine in the upperWaitekauri Valley, Coromandel was initiated in December 1989, before mining, as a requirement of the conditions of the Mining Licence and Water Rights. The panel's function is as a technical audit and advisory team - to provide independent technical review of design, construction, and execution of mining operations, slope remediation works, and reclamation/mine closure activities. The primary role of the panel is to act in the public interest by providing assurance to regulating authorities that the design and application of on-site mining operations accords with 'good industry practice'. Panellists are not involved in design nor as advisers, although until 1997 when explicit terms of reference were written, the panellists were a sounding board for some operational proposals. The panel functions to ensure that best mining industry technical standards are met. The costs of the peer review process are met by the mining company. Review of mining operations includes environmental matters such as land rehabilitation and water quality. The focus of this paper is on the process of peer review for environmental management factors rather than for structural and mine engineering.

Jan 1, 1998

By B Rusk, L Corriveau, P Emsbo, R P. Xavier

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Porphyry-Cu (Mo-Au) deposits and iron oxide-copper-gold (IOCG) deposits are both characterised by the presence of abundant halite-saturated fluid inclusions that reflect the circulation of hyper-saline hydrothermal brines. While it is widely accepted that brines involved in the formation of porphyry copper deposits derive from unmixing of moderate-salinity, intermediate-density fluids that exsolve from crystallising magmas, the source of brines that form IOCG deposits remains enigmatic and intensely debated. In this extended abstract, we summarise the fluid inclusion characteristics of both deposit types and present trace element compositional data for halite-saturated fluid inclusions from both porphyry copper deposits and IOCG deposits from around the world.While both deposit types typically contain halite-saturated fluid inclusions, vapour-rich fluid inclusions in IOCG deposits are less common than in porphyry deposits and evidence for fluid immiscibility is rare. IOCG deposits also typically lack intermediate-density fluid inclusions that characterise the deeper quartz-rich veins in many porphyry deposits. Many IOCG deposits contain CO2-only fluid inclusions, a type of fluid not observed in porphyry Cu deposits.Our fluid inclusion compositional data show that most porphyry Cu (Mo-Au)-related brines are dominated by Na, K and Fe and contain elevated concentrations of Ca, Cu, Pb, Zn and Mn up to around the one per cent level. On the other hand, IOCG brines are Na-Ca-Fe-dominated and typically contain far less Cu, Mn and Zn than porphyry brines. In addition to Ca, these fluids are also strongly enriched in Ba and Sr relative to porphyry-related brines. Such compositions are consistent with extensive fluid-rock interaction and/or an evolved sea water contribution to IOCG brines.A sea water or basinal brine source for IOCG brines is further supported by bromine concentrations that are much higher than is characteristic for porphyry-related brines. Porphyry brines have Cl/Br molar ratios of between 800 and 3000, which is characteristic of primary magmatic brines, whereas the Cl/Br composition of IOCG brines is more variable. For example, Na/Cl/Br ratios of most IOCG deposits in the world-class Carajás district fall on or near the sea water evaporation curve (most Cl/Br molar ratios are between 200 and 1000) and are diagnostic of sedimentary bittern brines. A few of the deposits in this district also show evidence of the input of subordinate amounts of magmatic brine. At Ernest Henry, in the Cloncurry district of Australia, most Cl/Br ratios plot close to the sea water evaporation curve, but Cl/Br ratios of up to ~5000 in several samples suggest the input of lesser amounts of magmatic fluids, and possibly evaporite-dissolution-derived fluids. Taken together with geologic constraints, these data strongly suggest that porphyry-type deposits form from the circulation of dominantly magmatic fluids, while IOCG deposits form from large-scale circulation of high-salinity fluids sourced dominantly from sedimentary basins with variable input of magmatic volatiles.CITATION:Rusk, B, Emsbo, P, Xavier, R P, Corriveau, L, Oliver, N and Zhang, D, 2015. A comparison of fluid origins and compositions in iron oxide-copper-gold and porphyry-Cu (Mo-Au) deposits , in Proceedings PACRIM 2015 Congress, pp 271–280 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By L R. Marshall, M J. Rubenach, T G. Blenkinsop, J S. Cleverley

The source and transport regions of fluidised (transported) breccias outcrop in the Cloncurry Fe-oxide-Cu-Au district, providing insights into the origins of other fluidised magmatic-hydrothermal breccias such as kimberlites. Discordant dikes and pipes with rounded clasts of metasedimentary calc-silicate rocks and minor felsic and mafic intrusions extend several kilometres upwards and outwards from the contact aureole of the 1530 Ma Williams Batholith into overlying schists and amphibolites. The brecciation initiated at depths >10 km and may have resulted in surface breaching. We used analytical equations for particle transport to estimate clast velocities (eÆ 20 ms-1), approaching volcanic ejecta rates (up to 80 ms-1). The wide range of CO2 fluid inclusion densities (up to 150 MPa), the localisation of the base of the breccias in contact aureoles, and the scale and discordancy of the bodies suggests the breccia transport process was triggered by an abrupt release of overpressured fluid. At these depths, such extreme behaviour may have been achieved by release of dissolved fluids from crystallising magma, in combination with a strongly fractured and fluid-laden source, sitting under a strong, low permeability barrier, and such parameters may be analogous to the asthenosphere/lithosphere boundary in the case of kimberlite initiation. The relationship of these breccias to the Ernest Henry iron-oxide-Cu-Au deposit suggests they may have been either fertile or æfailedÆ orebody feeders.

Jan 1, 2005

By Grace B, Cunningham D

The poor quality of bore waters available to the Australian mineral processing industry creates a climate for crystallization of calcium based scales. If ignored, calcite and/or gypsum buildup can cause loss of production and costly unscheduled maintenance. This paper discusses the factors which contribute to scale forma- tion, methods used to monitor buildup and preventative measures (mechanical and chemical) that can be used. A case history il- lustrates the value of using chemical antiscalants.

Jan 1, 1991

By Adams F. C, Ridley K. L

Economic conditions after WorId War II made the recovery of Australian sources of sulphur one of considerable national importance. From 1947 to 1949 an investigation was made of recirculation techniques to produce acid plant grade gas from the Dwight-Lloyd down-draught sintering plant.During 1949 it appeared feasible to produce a gas of suitable 802 concentration and a decision was made to construct a gas purification train and a 150 tons/day contact acid plant. However, a number of difficulties remained in the production of the gases for sulphuric acid manufacture and as a result of research conducted to overcome these troubles the continuous up-draught sintering process was developed.The principal difficulties were:(a:) The down-draught sintering practice, as developed, produced an unusually high metallic lead precipitation in the windboxes. The disposal of this lead interrupted sintering operations and the delivery of gas to the acid plant.(b) The production capacity of the existing sintering plant was fully extended and the adoption of recirculation of gases, in an endeavour to satisfy acid plant requirements, would probably reduce the plant production capacity.(c) The prevailing high temperature of water available for purification train cooling required a higher than...

Jan 1, 1956

The Youga gold mine in Burkina Faso, West Africa, is scheduled to produce first gold in the third quarter of calendar 2007. The project is expected to produce 540 000 oz of gold over 6.5 years, from a conventional open pit carbon in leach mine. The direct capital cost of the project is US$47 M. Etruscan Resources Inc, a Canadian based gold exploration and development company, holds 90 per cent of the project company Burkina Mining Company SA (BMC). The state of Burkina Faso is free-carried for the remaining ten per cent of BMC. RMB Resources Limited, of Melbourne Australia, has arranged a US$35 M project finance facility for BMC (the Borrower) as the majority of funding for the Youga project development. The loan facility was provided by RMB Australia Holdings and Macquarie Bank Ltd (the Lenders) each as to 50 per cent in the lending syndicate. The Lenders also provided a gold hedging facility to guarantee a minimum price for the projectÆs gold production. Burkina Faso is a francophone country, part of the Economic and Monetary Union of West Africa (UEMOA). The project financing is the first such facility to be arranged for a mining project in Burkina Faso, with little or no precedent available in other UEMOA countries. Therefore, while the Youga gold project is forecast to be a robust project applying conventional mining and processing methods, a number of legal, technical, commercial and social issues required identification, evaluation and resolution before the loan could be established. This paper describes that evaluation process and the resolution of these issues. In-house experience and expertise in both the LendersÆ and BorrowerÆs teams has facilitated a greater understanding and æownershipÆ of the issues and hence provided comfort with risks which might not normally be taken in conventional project developments and project financings. As a result, blanket external reviews were not required by the Lenders. A long-standing relationship between Etruscan and RMB Resources also facilitated solutions to a number of issues. Nevertheless, a degree of flexibility by the Lenders, the Borrower and Etruscan was required to successfully close the financing.

Jan 1, 2007

By D J. Brake

The correct specification and then selection of primary or major fans for an underground mine is a critical decision not only in terms of fan capital and operating costs, but also safety and reliability which usually has a major impact on mine production. In addition, fan manufacturers may spend tens of thousands of dollars preparing proposals for a purchase enquiry for primary fans especially where they have complete responsibility for the installation (turnkey projects). There are many good reasons to thoroughly and fairly adjudicate fan tenders. This paper describes the process to achieve this starting with the initial fan specification through to the final award.CITATION:Brake, D J, 2017. Fan specification and tender adjudication for mine ventilation engineers with particular reference to turnkey projects, in Proceedings Australian Mine Vent Conference 2017, pp 245–252 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

A variety of algorithms and methods are being used by the mining industry today to map mineral resource for reserve estimation. The traditional methods including Polygonal, Sectional and Inverse Distance methods are relatively easy to understand and implement. They have served industry well for several decades and should continue to do so for the large bulk mineable deposits with very regular geometries with relatively small variation in grade.

Jan 1, 1992