Search Documents

The hoisting system at the Newcrest Telfer mine is designed for a final duty of 7.35 million tonnes per annum at a hoisting distance of 1450 m. In terms of hoisting capacity (t/h) times hoisting distance it is one of the largest friction hoist installations. Initially, the hoist will be equipped for hoisting 6.5 Mtpa from 1100 m depth. This new drive technology is now well proven by ABB for mine hoist applications with the first installation in commercial operation since July 2001. To date 17 systems for medium voltage drives and another five for low voltage drives have been purchased from ABB for mine hoists. This paper will also deal with skip design and powerful data loggers with diagnostics for local and remote monitoring that are installed in the Telfer mine hoist.

Jan 1, 2005

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 Moylan T, Stewart D

A case study examining the procedures and financial benefits of introducing dump leaching to augment the Mt Gibson Gold Project CIP operations is discussed. Metallurgical testwork, followed by pilot dump leach operations, confirmed that gold recoveries of greater than 60 per cent could be achieved by dump leaching Mt Gibson laterite ore. Capital and operating costs were determined. Pit optimisation using the Whittle FOUR-D optimisation program calculated an optimum cutover grade between CIP and dump leaching for one orebody. The resultant recalculation of reserves based on CIP and dump leach operating costs showed that reserves for that orebody could be increased from 329 000 tonnes at 1.9 g/t An, to 1 488 000 tonnes at 1.2 gh An. NPV for the CIP only option of $1.4 m, was increased to $4.0 m for the combined CIP/dump leach option. This technique can be applied to existing gold projects and to new Developments.

Jan 1, 1992

In October 2005 Phelps Dodge mining, a US based company, visited several Australian mining companies and mine sites to ascertain the current applications of risk management methods in the organisation. The results of this review, documented by the author, indicated a ælayeredÆ approach from high level site or major hazard analysis through to face level, æstop and lookÆ, methods. The approaches of several companies were summarised in one simple layered model. This model is helpful to other sites and companies to identify potential improvements but also offers an image of best practice that may assist with the governance of OH&S by both company boards and community regulators. The issue is particularly relevant as we discuss national consistency in mining regulation. This paper examines the layered model, the company and site approaches that helped define the model, as well as the suggested implications of the layered model to governance.

Jan 1, 2006

By G du Toit, P L. Gillot, M Swanepoel

Randgold Resources’ Loulo-Gounkoto Complex is one of the largest gold mining operations in Mali, West Africa. The mine, which is situated on the western border with Senegal, treats more than 4 Mt/a of ore through a conventional three-stage crushing and ball milling circuit followed by a carbon-in-leach plant. Ore supply is achieved by a combination of open pit and underground mining, with the majority of the ore supply sourced from the Gara and Yalea underground mines situated approximately 2 km and 6 km respectively from the gold plant.In 2011, Randgold Resources commissioned Golder Associates to perform an evaluation study for providing structural backfill to both the Gara and Yalea underground mines using the current gold plant tailings. The test work performed as part of the evaluation study concluded the need for a tailings cycloning and dewatering facility capable of producing slurry at a solids concentration of 65 per cent with a particle size distribution that had minimum 25 per cent passing 20 µm and less than 5 per cent of -5 µm material. Tailings desliming was required to ensure a consistent feed quality to the paste preparation plants and to ensure that the system would be capable of handling variation in the feed composition from the gold plant.WorleyParsons, previously TWP Projects, was contracted by Randgold Resources to complete the engineering design for the slurry preparation plant, whilst Golder Associates was retained to complete the engineering design of the two paste preparation plants.This paper discusses the test work, design considerations and engineering design of the slurry preparation plant, termed the ‘intermediate plant’, as well as all ancillary facilities required for the delivery of the deslimed slurry to the paste preparation plants located at the two underground mines.CITATION:Swanepoel, M, du Toit, G and Gillot, P L, 2014. Case study – engineering design for a slurry preparation plant for a paste application in West Africa, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 477–486 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By M Saghaeian, A H. Baladastian, A Dehghani Ahmadabadi, V Sheikhzadeh, R Hejazi

This research was done to reduce silica from mixed hematite concentrate of Barfkar Iron Ore Sample and increase Fe grade using reverse flotation method (Depressing Hematite and floating Silica). The used sample in the reverse flotation tests was a mixture containing two types of hematite concentrates (Spiral cleaner concentrate and Slon-VPHGMS cleaner concentrate) with the percentage of 16 per cent and 84 per cent, respectively. Fe grade of two samples was 59.31 per cent and 57.52 per cent and SiO2 grade was 5.83 per cent and 6.71 per cent, respectively. After mixing, the Fe and SiO2 grade of the mixed sample was measured at 58.10 per cent and 6.20 per cent. For flotation tests, effect of variable operational parameters including feed size distribution (d80 = 130 microns and d80 = 53 microns), pulp solidity (25 per cent and 30 per cent w/w), pH (9.70, 10.20 and 11), Sodium silicate as a dispersant (500, 1000 and 2000 g/ton), Starch as a depressant (500, 1000, 2000 and 3000 g/ton) and EDA as a collector (180, 300, 400 and 500 g/ton) were investigated. For evaluating the influence of Sodium silicate and Starch dosage, initial flotation tests were performed on the main sample (d80 = 130 microns). These two parameters had no significant effects on the yield, Fe, and SiO2 grade of flotation concentrate based on test results. In the next step, screen analysis was carried out on the main sample for mineralogical studies. Accordingly, the suitable size distribution for releasing Fe and SiO2 particles was smaller than 53 microns. Therefore, the sample was crushed until d80 = 53 microns. Then, supplementary tests were performed on the crushed sample for studying the pH range, pulp solidity, and EDA collector dosage. After doing silica removal flotation tests based on the designed pattern and comparison of the results, the conditions consisting of size distribution d80 = 53 microns, pulp solidity 25 per cent, pH 10.20, Sodium silicate 1000 g/ton, Starch 1000 g/ton, and EDA 500 g/ton was selected as optimum values. In the last test, Fe and SiO2 grade was measured at 60.00 per cent and 3.93 per cent, respectively, and Fe recovery was obtained at 74.93 per cent.

Aug 24, 2022

By E Cunha, D Roldao, TáTamantini, J F. C L Costa, T Webber, C Monteiro

The main problem of geostatistical simulations is to reproduce the real characteristics of the mineral deposit when there are few conditioning data. In this case, the geological interpretation, based on structures, geophysics and geological maps, plays the major role in terms of resource evaluation.The paper investigates the use of principal component analysis (PCA) to help classify multiple geostatistical categorical simulations considering the similarity among them and the interpreted model, herein referred as training image (TI).An iron deposit with four lithological facies, in a specific horizontal plane, was used as case study for two-dimensional (2D) simulations. Sequential indicator simulations (SIS) was used to obtain ten equally probable 2D images, which were generated and compared against the interpreted model (TI).In this study, 11 random variables are comprised by the vector of ten SIS realisations plus the training image (TI). The similarity between the TI and each SIS realisation is measured using the angle between the TI and SIS vectors projected in the new coordinate systems (PCA factors). It is possible to order the SIS realisations from the highest to the lowest PCA factor taking into account the TI similarity.The visual analysis of the images shows coherence in the PCA results as a method to measure similarity. This methodology can be used as a post-processing tool to rank simulation results and to select the ones which better represent the prior known geology or to compare the quality of different methods of simulation.

Sep 26, 2011

By R Dunne, S Hart, G Levay

While water represents a major proportion of the mineral pulp processed in flotation circuits, relatively little research effort has been committed to understanding and controlling the influence of water quality on this process. Historically, this probably stems from the perception of water as an inert transport medium. However, the changing attitude towards water as a valuable resource, has given impetus to increasing requirements to use relatively impure make-up water supplies such as treated effluents and a high proportion of internally recycled water. In turn, this has resulted in the need for a more detailed focus on process water quality and its control to minimise adverse effects on sulfide flotation. Along these lines, prior to commissioning of a new concentrator at their Cadia Hill Gold Mine, Newcrest Mining was proactive in examining potential water sources and the influence of water quality on flotation of their copper/gold bearing ore. An extensive water quality survey of all major potential water supplies to the concentrator was undertaken. The flotation performance of the Cadia ore in each of these waters was investigated on a laboratory scale. The results of these studies identified that water quality could indeed have a significant influence on the flotation process. Since operations at the Cadia Hill concentrator began, water quality surveys of both make-up water sources and recycled flotation circuit waters have been carried out on a regular basis. By doing this, a database of water quality has been established which can be compared with plant performance. In parallel with the water quality surveys, a series of laboratory flotation tests have been conducted using a standard ore and waters from various streams to monitor changes in flotation performance as a function of water quality. These tests have indicated that certain water types may have a significant influence on plant performance. More research is required to better understand the impact of water quality on sulfide flotation. This understanding will help operators to minimise adverse effects, while maintaining the best utilisation of available water resources.

Jan 1, 2003

The coal resources of the Singleton- Muswellbrook area of New South Wales are of major importance to Australia, and are likely to play a significant role in meeting the expanding demands for energy in many countries of the world. Coal resources of 45 thousand million tonnes of which 15 thousand million tonnes lie at a depth of less than 200m have been estimated. The history of coal mining in the area commenced in the mid 1800's and has been one of fluctuations in production but of rapid expansion in more recent years. It is destined to become the largest coal producing area in New South Wales. Coal is being won from the area by strip mining, open pit mining and by underground means. The techniques involved are described. The area is well endowed with infra- structure such as modern towns, railways, road- ways and access to port facilities. Production of both coking coal and steaming coal is expected to rise significantly within the next 25 years. A large proportion of the State's anticipated increased production to between 117 and 177 million tonnes by the year 2000 is likely to come from this area.

Jan 1, 1979

The Sao Chico gold project is located on the Tocantinzinho trend which is the most mineralised zone in the Tapajos Mineral Field of Brazil (see Figure 1). The Tapajos goldfi eld was the site of the biggest gold rush in Brazilian history in the late 1970s and 1980s when approximately 500 000 garimpeiros (artisanal miners) rushed to the area to exploit extensive areas of newly discovered alluvial gold. Approximately 20 - 30 million ounces of gold were produced from these operations before the easily won alluvial gold deposits were largely depleted. The Tapajos region has had little exploration by modern exploration methods compared to any other equivalent gold fields in the world. The gold occurs in sulfide veins developed in shear zones within Proterozoic granites. Gold grades vary from approximately 15 g/t in the hard rock veins, to up to several ounces per tonne in the supergene weathered upper portions of the veins. Goldbearing vein zones in the weathered profile are free digging. In addition, tailings dumps from previous mining operations contain gold grades of approximately 1 g/t. Metallurgical test work conducted to date indicates that gold recoveries of at least 70 per cent can be achieved via gravity concentration. Gold Anomaly, via its 100 per cent owned Brazilian subsidiary, Gold Aura Do Brasil Mineracao Ltda (GOAB), plans to mine the tailings and weathered vein material by open cut methods to generate a quick cash fl ow and to provide a better understanding of the mineralisation as part of a feasibility study for mining the underlying sulfide zone mineralisation (see Figure 2). Mining will utilise locally hired excavators and trucks and ramp up to a rate of 100 tonnes per day. To treat the gold-bearing material, GOAB has purchased an integrated 'state of the art' gravity concentration processing plant from Gekko Systems of Australia. The processing plant includes a scrubber for clay and oversize removal, coarse gold gravity separation via an inline pressure jig and an inline spinner; and fine gold gravity separation via a Falcon Concentrator. The plant is expected to be operational by late 2010. This is an ABSTRACT ONLY. No paper was prepared for this presentation. 

Aug 1, 2010

By K Barns, H Law, T Whebell, P Scobie, T Perkins, J Siliezar, M Larson

With processing a variety of orebodies at Glencore’s Ernest Henry Mining (EHM) has come a changing mineralogy and more complex requirements for treatment in the concentrator. From mid-2013 and into 2014 the grind size required to achieve sufficient mineral liberation for production of a quality concentrate has reduced significantly. What was once a final P80 of 35–45 microns was forced to 20 microns. This has necessitated some creative changes to the flow sheet that previously had a 937?kW Vertimill regrinding a rougher concentrate to 40 microns. EHM is able to utilise an existing M10 000 3 MW IsaMill previously used for magnetite processing, to provide a quick convenient solution without large scale capital expenditures. Operating the Vertimill and IsaMill in parallel in closed circuit was successful at reducing the P80 of the regrind circuit to below 20 microns which increased the final concentrate grade by four per cent. This circuit and intermediate circuits used are discussed. Performance of the Vertimill and IsaMill is compared for efficiency optimisation to improve the overall circuit performance.CITATION:Siliezar, J, Whebell, T, Perkins, T, Law, H, Scobie, P, Larson, M and Barns, K, 2014. From magnetite to chalcopyrite – a story of versatility and efficiency at Glencore’s Ernest Henry mining?operation, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 85–92 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By Mowat B. A

I lamata is within the Morobe Goldfield (7¦ 25' S, 146¦ 39' E) on the Wau (SB 55-14),1:250,000 scale map sheet (Fig 1). The deposit is 13 km SW of Wau, within the headwaters of the Upper Watut River, at an average elevation of 2000 m. The steep mountainous terrain is covered by dense tropical rainforest and access is by helicopter or by foot track. The deposit has been described previously by Wells and Young (1991) and 1)enwer. Leach and Mowat (1995). Data collected to late 1996 have been used to estimate an Inferred Resource of 9.2 Mt at 3.1 g/t gold using a cutoff of 0.5 g/t. This contains a high grade portion for which an Inferred Resource of 1.2 Mt at 9.7 grt gold has been estimated using a 5.0 g/t cutoff.

Jan 1, 1997

By D Atheis, S Williams, A Dance, D Taplin

"Resurrected from its former life at the Big Bell operation, the grinding circuit at Evolution Mining’s Edna May operation in Western Australia has many a story to tell. The task of optimising a plant designed for another orebody provides as many challenges as opportunities. Initially faced with a blend of primary and oxide ore, the circuit achieved in excess of 320 t/h until the oxide was depleted, leaving only the much harder primary feed.The 2.0 MW semi-autogenous grinding (SAG) mill and 3.7 MW ball mill were assisted by a 150 kW pebble crusher, but the power limitation of the SAG mill resulted in a drop in throughput. Edna May personnel have been involved in a number of progressive improvements to restore the design capacity of the concentrator and work towards 3 Mt/a or even higher ahead of the gravity and leach recovery circuits.These improvements include: a crush forward configuration of the SAG mill scats partial to full secondary crushing variable speed drive upgrade of the SAG mill lifter and grate design changes ball mill circuit grinding efficiency.This paper summarises the chronology of events that has resulted in significant improvements in throughput by conventional (and in some cases, novel) methods of reconfiguring the existing grinding mills. Lessons learned and hindsight perspectives will be summarised, sharing this educational experience with other operations in a similar situation.CITATION:Dance, A, Atheis, D, Williams, S and Taplin, D, 2014. Grinding circuit improvements at Evolution Mining’s Edna May operation, in Proceedings 12th AusIMM Mill Operators’ Conference 2014, pp 63–70 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 1, 2014

By J Vann

Mineral Resource and Ore Reserve estimation is a challenging and demanding field, requiring application of professional knowledge, skill and experience of the highest order. If the many potential pitfalls are to be avoided, however, there are two other requirements which are of equal, if not greater, importance:good communication, and common sense. Estimation of Mineral Resources and particularly of Ore Reserves is almost always a team effort, involving a number of disciplines. Good teamwork requires good communication, both between team members and between the team and other parties having an interest in the process. Breakdown in these lines of communication can have far reaching effects on the project under consideration. The need to use common sense during a Resource or Reserve estimation exercise would seem to be self-evident. It is surprising, however, how often rigid adherence to procedures and methods prevails at the expense of clear thinking, usually with adverse and sometimes fatal effects on the project under consideration. This has become increasingly true as computerised methods have assumed a central role in Resource/Reserve estimation. The critical question that estimators should ask themselves at all stages of the process is: æIs what is being done sensible given the data available, what is known of this deposit and the purpose of the exercise?Æ

Jan 1, 1999

By JOHN G. RAYNER

An examination was made of the filtration characteristics of a haematite slurry using a range of polyacrylamide based flocculants in solutions containing up to 3 per cent sodium chloride. The polymers used were "high" and "Iow" molecular weight and had from 0 to 40 per cent charged groups.Increasing charge density tends to reduce the dose required to achieve optimum performance measured by filtration rate and by cake moisture. In general increased salt addition tends to increase the dosage required to achieve these optima. Both these observations result from the change in polymer extension and accord well with the bridging theory of flocculation.The dose required for optimal cake moisture is up to three times greater than that required for optimal filtration rate. This effect is reasonably consistent for all polymers studied and appears to be non-linearly dependent on salt concentration, with the difference being small at 0 and 3 per cent but quite significant at 1 per cent.

Jan 1, 1987

By D Clarke, R Simpson

The Main lode in the Anwia Gold deposit is difficult to interpret due partly to the fact that three separate grid and drill hole orientations exist over the area and partly due to a lack of understanding of the controls on the high-grade mineralisation. Scattered high gold grades and multiple veining orientations add to the confusion. Sectional interpretations of the lode are often misleading due to the multiple orientations of drilling. Initial attempts to define a high-grade constrained geological model were not successful due to the inability to establish any geological continuity that would hold together in three dimensions. As a consequence the initial geostatistical domaining for the Main lode at Anwia comprised a simple broad mineralised envelope split by the weathering profiles. Subsequently an analysis correlating subjective qualitative logging information with grade plus utilisation of LeapfrogTM software, together with extensive geological re-interpretation resulted in the definition of a coherent high-grade shoot within the Main lode. The resource was re-estimated including this new domain as a high-grade hard boundary. Estimations on both models were carried out using uniform conditioning, which is a recoverable resource estimation methodology that estimates tonnages and metal above a series of cut-offs for SMU (selective mining unit) sized blocks. This paper compares the tonnages and metal contents that are calculated from the two estimation runs, both at a zero cut-off and a series of higher cut-offs. The results confirm that the estimation methodology has been implemented correctly as the tonnage and metal content at zero cut-off is the same for both models. The resource tabulations and grade tonnage curves predicted by the two models highlight the differences that can occur at higher cut-offs when realistic high-grade domaining is implemented. The results also reinforce the point that recoverable resource models are intended to address selectivity issues and are not substitutes for good geological modelling. Recoverable resource techniques, such as uniform conditioning, will not correctly estimate high-grade zones that have not been explicitly modelled.

Jan 1, 2006

By S McEachern, J Lowe

An important issue currently facing the mining industry in Australia is the management and cost to the industry and other stakeholders of entry into and exit from towns and their communities. These costs can be environmental, social, economic, political or reputational. The ability of companies to engage the trust of stakeholders, including: communities, governments and investors, is critical, and corporate reputation plays a significant role in this. For the industry to secure a long-term and sustainable future, it must have the technical, business and reputation assets to proceed in a cost-effective, environmentally acceptable and socially supportive way. This research assesses reputation as a critical competitive issue for mining companies, as technology and information make mining more predictable; the physical and human assets of mining companies are less likely to be the critical resource in a Resource Based View model of competitive advantage. The proposition is that in mining today, reputation as it facilitates day-to-day operations, regulatory zeal and access to new mine sites will become the rare, inimitable and valuable resource for mining companies. This paper reports on an ongoing research program to evaluate the impact a mining companyÆs reputation(s), with its various stakeholder groups, has on a companyÆs ability to sustain competitive advantage. Integral to this study is to develop an understanding of the relationships between mining companies and their stakeholders, and the importance of corporate citizenship polices to reputation and hence to corporate sustainability. Through the identification of the drivers of reputation for the various stakeholder groups, a model of reputation formation will be developed and also reputation measures for the mining industry in Australia. The preliminary findings of this research, the results of an industry focus group conducted with representatives from regional mining operations, are reported. The industry focus group was designed to enable a better understanding of who are the main stakeholder groups and how they regard mining companies and to inform the second stage of the research project a Delphi Study of the drivers of reputation by stakeholder groups. The aim of this research is to further the understanding of the relationship between corporate citizenship, reputation and performance in the mining industry, thus assisting companies to strategically manage their corporate citizenship investments.

Jan 1, 2006

By Mernagh T, Large R. R, Ryan C. G, Huston D. L

The Tennant Creek goldfield is one of the largest gold producing districts in Australia, and major deposits, including Gecko, Juno, Orlando, Peko, Warrego, Nobles Nob, Golden Forty, Argo, TC 8 and White Devil have produced more than four million ounces of gold over the past two decades. Gold-copper-bismuth mineralisation at Tennant Creek occurs in lenticular, ellipsoidal or pipe-like bodies of magnetite-hematite ironstones which are hosted in turbiditic sedimentary rocks of Proterozoic age (Large, 1975; Wedekind, Large and Williams, 1989; Le Messurier, Williams and Blake, 1990; Morrison, Donnellan and Hussey, 1992).

Jan 1, 1994

By P Jackson, J Rea, M D. Goodz

The Morning Star Gold Mine has operated over a 101-year period, producing gold from narrow quartz veins and sulfide stockworks hosted mainly within a dioritic-gabbroic dyke. The deposit has been developed over a vertical depth of 980 m with drilling extending the vertical depth to greater than 1200 m. Currently there is a total Inferred Resource of 4.6 million tonnes at a grade of 6 g/t for 910 000 ounces of contained gold resources, which comprises an underground project and a surface project. Significant variation exists between the grade of drill core intersections and that observed in face sampling and subsequent production reconciliation (250 - 650 per cent). Studies were carried out on ten major production reefs, where the grades of drill intercepts were compared with face samples collected during development and mining. The implications of this study have been used as justification to assign production or stope/development grades where applicable to resources that are direct extensions of the historical development headings. Grade assignment and its impact on sensitivity for gold resources are detailed and show a 40 per cent variation in the gold resource, depending upon whether a production or calculated stope grade is used in grade assignment for the major reef deposits. Recent diamond drilling has intersected approximately 40 new gold bearing quartz reefs and sulfide zones that contain all the key mineralogical and structural indicators, and traditional large variations in gold grades similar to the historical major production zones. The implications of grade factoring and grade assignment are the greatest challenges confronting the resource estimation team in defining grade for these new zones. Grade assignment is seen as a method of balancing known historical production observations with the irregular grade distribution inferred from drill core assay results. Ongoing mine development and bulk sampling works are planned to validate the grade assignment process. The first stage of this process is the trial mining of the newly discovered Maxwell Reef (MR). The stope drawpoints were completed in August 2008 and the MRS1 stope is scheduled for completion in September. The stope reconciliation results will be presented at the October 2008 conference.

Jan 1, 2008

By T Ladinig

Raise caving is a novel cave mining method, which has been proposed for mass mining at increasing mining depths in LKAB operations. The method makes use of the raise mining technology and an active stress management approach. For the implementation the method is split into two phases, namely a de-stressing phase and a production phase. In the de-stressing phase, a slot-pillar system is established. The purpose of slots is to provide stress shadows and the purpose of the large pillars is to control stress and seismicity. The production phase follows after the de-stressing phase. Required infrastructure in the production phase is developed delayed in stress shadows and bulk extraction takes place in de-stressed zones. Eventually the pillars crush and they are extracted in the production phase. A comprehensive research and development program has been launched to develop the raise caving method towards implementation. As part of this program a full-scale test site of raise caving will be conducted as well as raise caving operations are planned for depth extensions in LKAB mines. This paper discusses the design of raise caving operations in practice at the LKAB mines. In particular, the purpose of the paper is to focus on requirements for the development and design of a raise caving operation. The development of raise caving is discussed from a systems engineering perspective as well as from a management perspective. The functional requirements in the destressing and production phase are outlined and discussed in the paper. The discussion is on basis of the main elements of the raise caving system, such as slots, stopes, pillars and infrastructure. Critical rock engineering design requirements in the de-stressing and production phase are highlighted and dependencies between individual main elements are identified. The analyses show that pillars are especially important for the success of the mining method. Overall, the analyses show that raise caving is a complex system and that its development demands a multidisciplinary approach.

Mar 29, 2023