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By L Sandery, S Light

Within 22 months of commencing decline development, the Prominent Hill Ankata Underground Project achieved its full production rate of 1.2 Mt/a.In 2010 construction of the Ankata Underground Project was approved. Decline development commenced in November 2010 and the turnout for the first sublevel was reached by August 2011. The first stoping ore was produced in the first quarter of 2012 and production was successfully ramped up to full production during the third quarter of 2012.Diamond drilling commenced in October 2011 and was conducted concurrently with the underground development. This presented challenges as mining and production targets had to be balanced with underground exploration activities. To achieve production on schedule, without adversely affecting the diamond drilling program and future development, meticulous and adaptive planning techniques were required. This included involvement from engineers, geologists, underground operators and underground diamond drillers.The granularity of these planning techniques allowed the management and prioritisation of development and diamond drilling down to an almost hourly basis. A constant flow of information from drill assay results was fed back into the planning systems. This resulted in a constantly evolving mine plan as the orebody was further refined. High priority areas were identified and targeted to allow continued development and a successful rapid ramp up to full production.CITATION:Sandery, L and Light, S, 2014. Managing the diamond drilling interactions in commissioning the Ankata underground mine, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 75–80 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

By A M. Avis

This paper presents an overview of recent developments in the Environmental Impact Assessment (EIA) process to provide the background for a more detailed analysis of environmental and social constraints that the Heavy Mineral Mining industry has encountered over the past decade. Four cases studies are reviewed to provide a context for further analysis and identification of cross cutting environmental and social issues that either resulted in the projects not proceeding, or in the Australian case study, places existing operations under significant pressure from anti-mining lobbyists. The Xolobeni project, from the Eastern Cape in South Africa, is presented as the primary case study because it is recent, topical, and accessible; and raised numerous issues related to mining in a sensitive environment. A proposal to mine an area adjacent to the Okefenokee swamps in 1997 was also met with strong opposition from various environmental groups in Georgia, USA. This case study is briefly reviewed to further understand what ultimately resulted in the project not proceeding. Opposition to mining at North Stradbroke Island is reviewed to identify current issues more applicable to a developed country. A further review of a strategic assessment undertaken at Wavecrest, Eastern Cape, South Africa is provided in support of possible solutions to the challenges identified in the case studies. Important common themes were identified, including in some cases unfortunate timing of the environmental studies, but in all cases opposition was due to ecological sensitivity, landscape quality and sense of place. In one case study limitations to the EIA process included inadequate detail in the specialist investigations and insufficient information on mitigation. In all cases public participation was a limitation. It was either insufficient; flawed through possible bias; too ‘top down’ and required engagement with mobilised, motivated lobbyists. There was also insufficient investigation of social impacts, particularly amongst rural communities directly affected by a project. Generally alternatives were inadequately considered, a recognised limitation of project level EIA. It is concluded that the EIA process should be started as early as possible (at prefeasibility), and that investigations should be expanded from a typical fatal flaw assessment to one that applies methodologies used in strategic assessment. In particular, opportunities and constraints of the natural and social environment should be assessed in the context of the mining option as well as other options, to allow for a more meaningful assessment of alternatives. Public participation must form an important part of this initial study, despite the potential risks associated with public engagement at an early stage in the project. The application of the IFC Performance Standards; and expanding the scope of the EIA into an environmental, social and health impact assessment will lead to a more rigorous procedure, and result in more defensible products which could successfully unlock the key to the resources in these sensitive areas.

Oct 5, 2011

By M Pizey, P Lindsay

Coal mining has been occurring on the Stockton Plateau for over 100 years. As a result of both natural conditions and mining activities, surface water on the plateau is known to have low pH and elevated metals concentrations, a condition known as acid rock drainage (ARD). Solid Energy New Zealand Ltd (SENZ), as owners of the current mining operations at Stockton desire to understand the nature and causes of ARD at Stockton to determine whether commercially viable options can be developed to improve the water quality to levels acceptable to the local community and regulators. A series of integrated water quality investigations have been performed towards developing a characterisation of the water quality on the Stockton Plateau and receiving waters. The investigations performed include: design and implementation of a water quality monitoring program to collect a satisfactory base of water quality data from which to develop an understanding of the water quality and its variability, and to collect data regarding the range of flow rates that occur in the principal streams; development of a hydrological model for the Plateau with the ability to predict flow rates at key locations on the plateau and on the Ngakawau River; field investigations of the bio-diversity of the plateau and surrounding areas, to develop a snapshot of the health of aquatic communities and whether streams draining mine workings are æadversely impactedÆ; eco-toxicology; waste dump seepage water quality monitoring at selected basal springs, drilling, investigations and permeability and geochemical testing; data processing of a range of historical data and the newly acquired data for the development of empirical relationships that describe the water chemistry system and its relationship in turn to flow rates in the streams; simulation of the long term water quality record for the measured parameters (pH, acidity and metals concentrations), based on the hydrological model and the empirical relationships developed from the new database; and preliminary development and examination of mitigation options for the ARD issues at the mine. The study has progressed towards design of pilot studies of options for mitigation of the generation of the ARD as well as treatment of the discharges. It is the integrated approach adopted by SENZ from an early time in the investigations, that has enabled fast-tracking of the pilot engineering trials. This paper presents the results of the field investigations and eco-toxicology studies and demonstrates the value of predictive modelling of water quality in the study area, even at a very early stage in the remedial engineering design process.

Jan 1, 2003

The West Fork project is located in Reynolds County, Missouri, in the mineralized zone referred to as the Viburnum Trend. The West Fork orebody has a calculated ore re- serve of 13 600 000 tonne (15 000 000 st) con- taining 5.5 per cent lead, 1.2 per cent zinc, and recoverable values of copper and silver. A total of 64 600 tonne (71 200 st) of lead concentrate and 11 300 tonne (12 500 st) of zinc concentrate will be produced annually. The mill was designed to operate at an average capacity of 3450 tonne/day (3800 st/day), based on a 95 per cent availability factor. The mill will operate 24 hours a day, 5 days a week, with maintenance performed, as needed, on weekends. The mine will operate on an identical schedule; but the underground, pri- mary crushing will operate on a six hour/shift, three shift/day schedule. The 1.07m x 1.22m (42in x 48in) jaw crusher will produce a minus 20cm (8 in) material at an average rate of 191 tonne/h (211 st/h). The jaw crusher has almost twice the throughput capacity required, but the decision to install that size of crusher was based on the need to handle over sized rock in the ore.The coarse crushed ore will discharge into a 180 tonne (200 st) skip pocket, which will allow up to a one hour surge capacity prior to hoisting. Hoisted ore will discharge into a 900 tonne (1000 st) storage bin located adjacent to the headframe. The skip pocket and coarse ore silo comprise the total ore storage capacity. The concept of having no intermediate fine ore storage between the secondary crushing and grinding sections was borrowed from the Brushy Creek Mill of St. Joe Minerals, which operates adjacent to the West Fork property. Integration of the secondary crushing and grinding circuits has worked ' successfully for years at the Brushy Creek Mill. The most obvious advantage to eliminating the intermediate fine ore storage is'capital expen- diture savings. The capital expenditure savings include the cost of silos, feeders, and the cost of additional conveyor length and eleva- tion. Savings in operating costs will also be gained, particularly in reduced maintenance costs. Other factors which influenced the decision to eliminate fine ore storage were the simplicity of the secondary crushing sec- tion and the limited area available for con struction of the facility

Jan 1, 1978

By Chappell B

Backfill in the form of mine waste tailings has inherent problems associated with attaining adequate strengths upon placement. Fines are usually removed to ensure adequate drainage, which lowers the cohesive strength of the fill, leaving the fines to he placed in a tailings darn. Electro-drainage and electro-chemical grouting is examined to investigate its effects on densification and shear strength within a silty clay tailing having low permeability and shear strength. Two separate grouting mechanisms are observed for the iron and silica grouts used. Electro- osmosis is associated with iron grout that deposits within the tailing matrix under a converging pH gradient, and increases the permeability of the tailing. This process initiates cation exchange and causes cementing of the granular contact points between the clays. Electro-phoresis causes sodium silicate solution to deposit silica grout in the voids of the tailings. The resultant effect of these mechanisms results in an increase in cohesion, leaving the void ratio of the iron grouted tailings as it was but significantly reducing the void ratio of the silica grouted tailings.

Jan 1, 1998

By J Sigda, T Jones, D Staggs, J Ewing, C Cheng, J Pickens, S Paulka

Mine-derived solutes from Energy Resources of Australia’s (ERA’s) Ranger uranium mine have been closely monitored for decades. Ranger is surrounded by the Northern Territory’s Kakadu National Park and is upstream of Ramsar convention wetlands. Modelling of groundwater flow and solute egress from mine wastes to surface waters has helped ERA successfully assess closure options and secure intermediate regulatory approvals during the site closure process. Potential environmental impacts were assessed using groundwater modelling in support of three ERA applications involving disposal of tailings-derived mine waste. Model results were an important part of the basis for obtaining regulatory approval. Three case studies are presented describing the three applications and how the groundwater modelling supported approval of the applications. For case study #1, INTERA supported ERA in addressing stakeholder concerns in 2017 regarding two aspects of tailings deposition in Pit 3. The first was the potential for flow of tailings fluid into the surrounding formations during tailings deposition. The second was the difference in post-closure magnesium (Mg) loading to surface water for two tailings deposition scenarios. INTERA developed a two-dimensional (2D) model that showed excess tailings pore pressures would not cause outflow and solute egress from the pit during deposition. INTERA’s three-dimensional (3D) models demonstrated that post-closure Mg loading to creeks for both tailings scenarios differed marginally and would be a small fraction of natural creek Mg loads. The modelling results helped avoid delays in completing tailings deposition driven by stakeholders’ environmental concerns. Case study #2 consisted of supporting ERA’s 2019 request for approval to change the tailings deposition method and final tailings level in Pit 3. INTERA’s model results for the permitted and proposed deposition methods showed minimal differences in post-closure Mg loading to creeks. The model results helped ERA obtain the needed approval for the tailings deposition method and water and tailings levels in Pit 3. For case study #3, INTERA modelled the comparative impacts from leaving the entire contaminant plume from the temporary tailings storage facility (TSF) in situ or excavating a portion of the contaminated material from beneath the TSF floor and placing it in Pit 3. The modelling results supported an approved TSF contaminated material application important for ERA to stay on schedule and minimise both closure costs and environmental impacts.

Jul 1, 2021

By T Elkington, A Finch

The theory of constraints (TOC) is a business improvement method that focuses on exploiting a business’s bottleneck to deliver the highest possible profit. Early applications were mostly in the manufacturing industry; however, the theory in itself is completely generic and has now been applied widely in other industries such as services, retail, software and distribution, amongst others. The intent of the approach is attractive – it focuses on the ‘silver bullet’ rather than ‘death by a hundred projects’, and it focuses on growth rather than cost cutting. Application within the mining industry has been limited to date, although there are a few applications emerging. This paper discusses how TOC can be applied to maximise value during the project planning phase and how to maximise profits when the mine is operational. The paper uses two case studies to illustrate the approach. Case study 1 uses the approach to improve tactical mine planning, which delivers an increase in revenue of 58 per cent. The second case study is a strategic mine planning example that delivers an increase in value of 77 per cent.CITATION:Finch, A and Elkington, T, 2014. Application of the theory of constraints to strategic and tactical mine planning, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 129–136 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By J H. J Holtzhausen

Never has there been more focus on the health, safety, and well-being of our employees at the workplace. Ever evolving expectations of individuals, companies and clients are shaping regulatory reviews and advancing standards across the world in the drive to zero harm. The technology is advancing at a rapid pace, which is now allowing continuous real-time monitoring of contaminants to take place in the harshest of environments.

Oct 12, 2022

By R Cooksey

The Globe-Progress Mine is an open pit gold mine that is part of the larger Reefton Goldfields deposit located on the West Coast of New Zealand. The regional geology comprises a series of north to south oriented fold structures that have undergone post-deformation mineralisation. The structural geology within the mine itself is more complex, with major shears hosting numerous high-grade mineralised quartz shoots and splays that have been historically mined.The selective mining of ore within the pit is challenging due to the orientations of the hanging wall and footwall areas of the main Globe shear zone, the lithologies of these areas which range from highly brecciated and sheared material to competent mineralised host rock, and in the hazards presented by the numerous old historic underground workings. The coordination of drilling, modelling and excavation of the ore requires careful planning to maximise recovery whilst operating with the pit design boundaries.Grade control packages are custom designed to reflect the orientation of the footwall and hanging wall mineralisation. The shear material in the footwall zone dips between 60° and 70° and requires angled drilling whereas the footwall mineralisation is contained in shallow dipping quartz veins sub parallel to bedding and can be vertically drilled to best intercept the mineralisation. Ore excavation is directed so that the contact between the footwall and hanging wall is mined in the correct direction so that any non-visual ore contacts can be safely mined and that the ore-waste dilution is reduced.The ongoing grade control and selective mining of the Globe Progress deposit continues to deliver high grade ore for processing by ensuring that waste and dilution of ore is reduced and that recovery is maximised.

Aug 22, 2011

By G Chen

Magnesite and dolomite are two salt-type minerals. The surface characteristics of these two minerals are almost the same. It is very difficult to remove dolomite from magnesite ores by flotation process. The present study was performed to develop a new collector and a better flotation scheme for magnesite from dolomite. The flotation tests show that there exists a significant difference in flotability between magnesite and dolomite when dodecyl phosphate synthesised with dodecanol, phosphorus oxychloride and other chemicals is used as collector. Sodium silicate was used as the modifier to improve flotation selectivity. It was found that sodium silicate selectively depressed magnesite at pH 4.5 - 7.5. The separation of magnesite from dolomite was achieved in a reverse flotation which resulted in a 76.1 per cent yield of magnesite with a grade of 47.3 per cent at 100 ppm dodecyl phosphate and 75 ppm sodium silicate. The flotation mechanism was investigated by characterising surface electrical properties and measuring the adsorption density of the reagents on magnesite and dolomite.

Jan 1, 2005

By D P. Sainsbury, J Western, B L. Sainsbury, V Mutton, P E. Petrie

Remnant rib pillars at Castlemaine Goldfields Ltd’s Ballarat Gold Project have been sterilised by the placement of loose rock fill in production stopes. The application of selectively injecting low-viscosity grout into the backfilled stopes to form a stabilised material has enabled recovery of the previously sterilised pillars. This paper outlines the engineering design, quality control and quality assurance program implemented to ensure the safe and efficient recovery of the rib pillars. The successful program included laboratory testing, numerical exposure stability modelling and in situ monitoring.CITATION:Sainsbury, B L, Sainsbury, D P, Western, J, Petrie, P E and Mutton, V, 2014. Pillar recovery adjacent to stabilised rock fill at the Ballarat Gold Project, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 77–86 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By C Armstrong, B Wentzinger

Upstream embankment raises often represent the lowest cost option for increasing the capacity of tailings storage facilities (TSF), but also pose the highest stability risk due to constructing on top of previously deposited tailings.This paper presents an overview of key aspects in the geotechnical investigation and design of upstream raises and some recent lessons learnt from experience across a number of TSFs in Australia. A summary of recommended field investigation and laboratory testing methods is provided with a focus on collecting quality information for design purposes. A strong focus is given in developing an accurate assessment of pore water pressures, which, if not correctly understood can have disastrous consequences on tailings strength parameter interpretation and wall stability assessment in static and post-seismic conditions.The assessment of the contractive or dilative shearing behaviour of the tailings material and rigorous interpretation of design characteristic values are presented. Some comments on stability analysis options and proposed methodology are also provided.CITATION:Wentzinger, B and Armstrong, C, 2018. Lessons learnt in geotechnical investigation and stability analysis for upstream tailings storage facility raise design, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 333–348 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By T G. Vizcarra, B Wong

Optimisation projects are regularly undertaken without knowing the root cause of an issue. It is all well and good to trial a multitude of flotation reagents, change the operating characteristics of your flotation cells, or add more media into your ball mills, but time and again, root cause analysis traces issues back to the performance of hydrocyclones. In JKTech's experience, hydrocyclones are poorly operated and maintained (in both primary grinding and regrind circuits), exacerbating issues that many operations commonly experience.Recent case studies are presented where JKTech has been engaged to improve the process only to discover that the hydrocyclones were the main issue. At one operation it was found that the hydrocyclone feed density gauge was reading significantly lower to the actual density. Following re-calibration of the gauge, and with further improvement of cyclone operational and design parameters using JKSimMet, a significantly sharper efficiency curve was achieved. This resulted in improvements to downstream recoveries while alleviating pumping capacities that were previously constrained by fines and water caught up in recirculating loads.Several other case studies are presented which may seem to be relatively basic, but many basics seem to be getting lost in the day-to-day responsibilities of the modern plant metallurgist. Simple fixes to hydrocyclones can result in significant production increases, but more focus is needed in monitoring these to sustain the benefits.CITATION:Wong, B and Vizcarra, T G, 2018. What category cyclone is devastating your plant?, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 665–673 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By Balint F

The Izok massive sulphide deposits are located in the Northwest Territories of the remote western Canadian Arctic. Together they represent one of the highest grade undeveloped zinc-copper resources in North America. Metall Mining Corporation is presently engaged in a feasibility study on developing the Izok property as well as actively exploring for additional reserves. The Izok deposits are Archean-aged, volcanogenic massive sulphide (VMS) bodies hosted within and near the top of a thick sequence of predominantly felsic pyroclastic rocks. The hangingwall package includes additional felsic volcanoclastics, dacitic and basaltic flows, thin sulphide-rich iron formations, and turbiditic sediments. The felsic volcanics are intruded by syn- to late-hydrothermal dacitic dykes and sills and post-hydrothermal gabbroic dykes and sills. Both intrusives are interpreted to be volcanic feeders to overlying flows. All lithologies are cut by much later irregular granitic pegmatite dykes and regionally metamorphosed to pyroxene homfels grade. The deposits occur within a large kilometre-scale soda-depleted alteration zone. The immediate footwall and hangingwall rocks to the deposits are characterised by zones of muscovite-biotite (with or without sillimanite), lesser chlorite-biotite-cordierite (with or without anthophyllite), and locally intense silicificified and albitised zones. All lithologies have been affected by a later calcic metasomatic alteration. As currently defined, the Izok Zn-Cu-Pb-Ag deposits comprise a cluster of four complexly-zoned composite lenses: the Northwest, North, Central, and newly discovered Inukshuk deposits. The first three deposits are amenable to open pit mining while development of the Inukshuk deposit will require underground methods. The combined mineral inventory of the Northwest, North, Central and Inukshuk deposits at present totals 15.6 million tonnes with a grade of 2.4 per cent Cu, 13.8 per cent Zn, 1.4 per cent Pb, and 74.6 g/t Ag.

Jan 1, 1993

An empirical method of estimating dense rock (D.R.E.) equivalent volumes erupted as airfall tephra, described in a companion paper in this volume, is elaborated, and its accuracy discussed. Estimates obtained from a single eruption can be classified as to whether they show positive, negative, or constant relative dispersion. For positively dispersed tephras (estimated volumes increasing with distance), this procedure improves the accuracy of the method. The technique is applied to selected andesitic tephras erupted from Egmont Volcano, New Zealand, during the last 28 000 years, which are found to range in volume from about 1.5 x 107 m3 up to about 2.4 x 108 m3 D.R.E. With a factor of about 16 between the smallest and largest volumes, this contrasts sharply with the rhyolite volcanoes in New Zealand, where the difference factor is usually of the order of 100. The largest tephra eruptions at Egmont are small compared to the largest debris avalanches, which have exceeded 1010 m3 (10 km3) in volume.The magnitude versus frequency relationship, calculated using a maximum likelihood method, establishes the limits of eruption magnitude at Mt Egmont as 107 to 109 m3 D.R.E. For some volcanoes, the magnitude-frequency relationship changes with time, owing to clustering of eruptions, separated by long dormant intervals. Ngauruhoe Volcano, New Zealand, is an example. Within eruptive episodes, the mean interval between eruptions of >_ 105 m3 is about 0.9 ¦ 0.65 years. The mean interval between eruptive episodes in which >_ 106 m3 is erupted, including episodes in which this volume is erupted gradually, is about 25.8 ¦ 6.6 years, and the mean dormant interval between all episodes is about 5.2 ¦ 3.0 years. At present Ngauruhoe is in an unusually prolonged dormant period, 50% longer than any in the historical record, since 1839.

Jan 1, 1990

By Lawrie DC

Finely ground beryl was decomposed by mixing with ground limestone and soda ash andheating at 900¦C for,4-6, hours.The sintered material was then crushed and leached by boiling under reflux with 5N sulphuric acid for up to 4 hours. The liquor containing Be, ; Al, . Fe and, other elements as sulphates, was separated from the residue which consisted mainly of silica and gypsum, either' by filtration or by decantation washing.The clarified leach liquor.was first treated to remove Fed}: , by contacting with a primary amine-kerosene solution in2 counter-current stages. The iron free liquor wa,s then passed to a 4-stage counter-current extraction unit where it was con-tacted with 0.5M di-(2 ethyl hexyl), phosphoric acid (EHPA) in kerosene. The'operating conditions were such that at least 99 p'br cent of the Be and only 7' per' cent of the Al- was, extracted The ,B6`= and. Al were ;stripped from the organic phase by sod-ium hydroxide solution of suitable concentration to form soluble "beryllate" and "aluminate" respectively. Most of the Be was subsequently precipTitated a's Bo(OH)2 by-hoating the alkaline solution to 90C, the Al remaining in solution. After filtra-tion and washing, the Bo(OH)2 could be ignited directly to BeO at about 1000 C or used as a feed to further purification stages aimed at producing "nuclear grade" BeO.A small coaAter-current extraction unit was operated con-tinuously using liquor derived from the sintering and leaching stages. Data obtained in batch laboratory tests were confirmed. A product obtained by ignition of the washed "beryllate" precip-itate contained more than'99 per cent BeO.

Jan 1, 1963

By Blattner P

The Late Miocene gold-silver bearing epithermal system at Waihi has some close similarities in its paleo-thermal and -geochemical structure with modern, volcanic-hosted geothermal systems such as Ohaaki-Broadlands. At Waihi an extensive braided quartz vein system is enveloped by hydrothermally altered andesites with minor tuff breccias and tuffs. A main stage of vein filling consists of multiple phases of chalcedonic quartz and fine to medium grained quartz, which are accompanied by pyrite, sphalerite, galena, chalcopyrite and acanthite below the base of oxidation. Platy calcite is present locally. Fluid inclusion studies indicate that the main stage quartz was deposited at temperatures of 189¦-273¦C from dilute (T¦ of -0.1 to -1.0¦C) fluids that were locally boiling. Homogenisation temperature Th versus T. data points lie within the field enveloped by dilution and boiling/gas loss paths determined for the Ohaaki geothermal field, and indicates that the parent hydrothermal fluid for the Waihi epithermal system had a similar composition to that at Ohaaki, ie 0.2 wt% equiv NaCI and 3.3 wt% equiv CO2. The hydrothermal alteration mineralogy and the isotopic composition of vein calcite indicate that the hydrothermal fluid contained relatively high concentrations of CO 2' as at Ohaaki. Oxygen isotope analyses of main stage quartz range from 6.1 to 11.6 %o and of vein calcite from 2.29 to 9.4% . Calculated d8Ow.½ values for the hydrothermal fluid that deposited the main stage quartz range from - 2.0 to -5.7%c , with a trend to less negative values with depth. They are similar to those in the deep chloride fluid in active geothermal systems with a substantial fluid throughput. A high fluid throughput at Waihi system is also evident from the extensive high intensity hydrothermal alteration and large volume of quartz deposited in the vein system.

Jan 1, 1995

By F Sahlström, E M. Jolis, V R Troll, E Jonsson, K Högdahl, C Harris

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Bastnäs-type magnetite-skarn-hosted rare earth element (REE) mineralisations are located in the Palaeoproterozoic Bergslagen ore province, central Sweden, and occur along a ca 100 km long belt of 1.90–1.87 Ga metavolcanosedimentary rocks. Ten different Bastnäs-type deposits have been sampled in order to assess the origin of ore-forming fluids in these systems. Magnetite and quartz have d18O values ranging from -2.3 to +1.1‰ and +7.2 to +8.3‰ respectively. Mineralised carbonates have d18O values between +5.8 and +7.2‰ and d13C values between -5.4 and -3.3‰. Temperature calculations based on the O-isotope composition of mineral pairs, combined with available fluid inclusion data, suggest primary mineralisation at ca 650–400°C. For these temperatures, calculated equilibrium fluids have d18O values that range from those typical of magmatic fluids (+6 to +8‰) to lower values (down to +3‰). Variation in carbonate O and C isotope data are consistent with interaction between local Palaeoproterozoic carbonate rocks (d18O = +12.5 to +19.6‰ and d13C = -1.8 to +1.7‰) and fluids of a magmatic origin. It is suggested that the Bastnäs-type REE-magnetite mineralisations formed as a result of reactions between local carbonate units and high-temperature, magmatic-dominated hydrothermal fluids during 1.90–1.87 Ga (Svecofennian) syn-volcanic activity.CITATION:Sahlström, F, Jonsson, E, Högdahl, K, Harris, C, Troll, V R and Jolis, E M, 2015. O and C isotope study of Bastnäs-type rare earth element mineralisation, Bergslagen, Sweden, in Proceedings PACRIM 2015 Congress, pp 439–444 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By J Herrmann, J Richards, B Hutchison

An extensive trial of laser-based survey and monitoring systems at Hillgrove Resources Kanmantoo Copper Mine in the Adelaide Hills, South Australia, has proved the capabilities of the system in monitoring rock movements on open pit walls. Initially, the trial involved deploying a Maptek I-Site 8820 laser scanner and the proof-of-concept Maptek Sentry software in the Nugent Pit to monitor ductile rock movements located up to 260 m away. The system was proven to be capable of monitoring various rock movements from 1.5 tonne rockfalls up to a 40 m high toppling wall failure. Data collected from smaller rockfalls was used to help build a database for Hillgrove’s rockfall management program. As part of the trial, the laser scanner was deployed to monitor a ramp movement event, as well as the toppling failure, adjacent to an IBIS slope stability radar. Both devices monitored the slump and the slowly developing toppling movements, with similar results. Although the radar was used as the successful ‘critical alarm’ device for the toppling failure, post-failure analysis showed the laser-based system to be capable of performing a similar role in the ductile rock regime; albeit over much shorter distances than the radar capability. A second laser scanner was deployed to monitor Kanmantoo’s Emily Pit in early December 2014, where it successfully provided critical alarm warnings for a block topple event. Sentry software, which takes advantage of Maptek I-Site 3D spatial imaging technology, was first released in November 2014 to meet industry demand for a cost effective, flexible system to detect movement. Sentry has now been re-launched as a fully transportable monitoring system. Deployed in a custom trailer, the system offers a power and communications module, cellular and Wi-Fi networking and a stable bollard for the I-Site laser scanner and Sentry software. This paper will present rock wall movement data from the Sentry trial and a subsequent two years of monitoring of the open pit walls at the Kanmantoo Copper Mine, at distances out to 750m. In addition, examples of remote geological mapping and small rockfall detection, using the laser scans, will be described. The Sentry system has proven to be beneficial for the continual improvement of slope monitoring and risk management at hard rock mines. CITATION:Hutchison, B, Richards, J, Richards, J and Herrmann, J, 2018. Mine rockfall and rock wall failures – proven digital laser-based approach for monitoring slopes at the Kanmantoo Copper Mine, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 463–472 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By D W. Evans

Research into the dynamic properties of ground support elements continues to grow at a global level, given the increasing importance of this field of application within underground hard rock mining. Measuring the mechanical response of such elements under the rapid onset of simulated rock burst loads forms the basis for this experimental work, typically utilising gravitational drop testing methods. This field of research is fundamentally driven by an increasing need for dynamic performance data, given the constant evolution of rock bolting product designs, materials selection, combination testing and specific application needs based on ground types and loading scenarios. A smaller number of globally recognised dynamic test facilities have predominantly lead research within this arena, typically in association with academic institutes, larger industry groups and government research institutes. However, due to the increasing requirement for dynamic performance data, additional facilities have now emerged in order to satisfy the overall demand for test work. These newer facilities are more typically associated with suppliers to the underground hard rock industry, with experimental designs looking to replicate, at least in part, the work of the primary facilities. For standardisation, repeatability and calibration purposes, the cross validation of test data between primary and secondary facilities becomes an obvious and important consideration across this field of research. This paper outlines the development of a new dynamic drop test facility for testing rock bolts, including the structural design and associated high speed data capture system. Based on the utilisation of identical bolt types, material grades, anchoring systems and decoupled ‘free-lengths’, comparative data has been generated to provide cross validation of the new test facility against data generated by a globally recognised primary facility. The cross validation of data provides increasing confidence in the repeatability and accuracy of the new facility as activity continues towards the provision of further experimental test work.

Nov 29, 2022