Search Documents

By McMullen P. H

Mining of copper ore at Mount Lyell has been continuous since 1893. The operation has always been marginal and the depressed copper Market over the last decade has seen mining continue on the basis of a series of short term plans. In 1985 it was determined that the mine would close in 1989 on completion of the 40 Series mining block. Significant changes in the value of the Australian dollar in 1986 and the subsequent effect on profitability dictated a review of the Company's operations. Lower level ore reserves, mining methods and ore handling systems were re-examined and a plan proposed for mining of the 50 and 60 Series mining blocks. The improved economics of this plan, together with workforce and State Government initiatives resulted in an extension of mine life to 1994.

Jan 1, 1988

By S Moradi

The thickener overflow of zinc concentrate, obtained from flotation process in the Angouran plant located in Iran, contains a large quantity of slimes which were transferred to the tailing ponds. These slimes have caused problems of storing and environmental aspects in the Angouran area. The objective of this research is to describe the extraction of zinc from these slimes by leaching method using sulfuric acid in pilot plant scale.Chemical analyses showed that these tailing materials contain 35 per cent of zinc. By XRD analysis, smithsonite is identified as the major constituent. Calcite, dolomite, and cerussite are found as carbonate minerals. A minimal amount of Zn occurs as hemimorphite. Quartz, kaolinite, clinochlore and muscovite are other silicate minerals in the slimes.In the optimal conditions, ie acid leach at pH of 1, temperature of 55¦C, reaction time of 120 minutes and solid-liquid ratio of 1:3 and neutralisation with Ca(OH)2 at pH = 4.5, temperature = 70¦C, time = 90 minutes, the total recovery of zinc obtained was 95 per cent.

Jan 1, 2004

During the later part of 2007 I was lucky enough to visit the Atlas Copco facilities in Sweden, and to see first hand what a large and diverse company Atlas Copco is. The reason this paper calls the Atlas Copco experience a bonanza is that it means a source of great and sudden wealth or luck; a spectacular windfall or a rich mass of ore, as found in mining. I think this aptly describes the scholarship as it has greatly increased my wealth of knowledge of the mining industry. This paper intends to encourage all those eligible to apply for this fantastic scholarship opportunity, and seeks to thank all those involved who made this scholarship the amazing experience that it was. Atlas Copco produces most of its Swedish products in the town of +rebro, and it was here that I spent most of my time, visiting the Underground Rock Excavation group, the Surface Mining Equipment group and Rocktec. I also travelled around Sweden and was able to visit one of OricaÆs manufacturing plants, the Secoroc groupÆs manufacturing plant, the Geotechnical Drilling and Exploration group as well as being fortunate enough to visit the LKAB mine in the Arctic Circle in Sweden. The trip was not all information on Atlas Copco products and services however; I was able to go to the Ice Hotel in JukkasjSrvi and drink Absolut Vodka out of ice glasses, go on a reindeer safari (as well as eat them!), sample the fine meat from a moose, drink local schnapps, attend the Atlas Copco Christmas party, wander around the wonderful city of Stockholm and generally immerse myself in the great Swedish culture.

Jan 1, 2008

Before presentIng my address I wish to acknowledge the honour which has been conferred on me by my appointment to the position of President of the Australasian Institute of Mining and Metallurgy.It is a matter of great concern to us all to find our Empire at war. I am confident that, as was the case in the war of 1914-1918, members of this Institute and of kindred Institutes and Associations will contribute in full to the Empire's needs and that in the end our cause shall triumph.I think it appropriate that I should take as the subject of my address that of the Broken Hill Lead-Silver-Zinc Industry. The subject matter of this address has been confined to the operations of Mining, Ore Dressing, Lead Smelting and Refining and production of Electrolytic Zinc in Australasia. The review of the Broken Hill Lead-SilverZinc Industry would not, of course, be complete without reference to those Australian industries which trace their origin to the Broken Hill field, but· it is thought that an outline of these industries would make thIs review too extensive.HISTORICALMany efforts have been made to translate the early history of Broken Hill and its subsequent growth throughout the years into one of the wor~d's most famous mining fields in the form of a simple story.

Jan 1, 1940

By R Bertuzzi

"This paper presents preliminary results of ongoing research being carried out at the University of New South Wales Australia (UNSW) into improved methods for estimating rock mass strength. In this paper the rock mass strength of Hawkesbury Sandstone is assessed. An estimate is first made based on an extensive database of intact rock strength data being collated by the author and the assumption that rock mass strength can be determined following the geological strength-index (GSI) approach. The resulting strength envelope is then compared with nine documented case studies where stress induced failure has occurred in tunnels excavated within Hawkesbury Sandstone. The case studies cover a range of conditions: construction dates from 1880s to 2006 spans from 3.2 to 12.5 m depths from 17 to 124 m excavation methods of drill and blast, roadheader and tunnel boring machine (TBM).Finite element modelling is used to assess the likely magnitudes of the principal stresses that were present at the time of the failures. The finite element models are interrogated to provide the values of major and minor principal stresses in and around the mapped failure zones. Failure and stable points are then compared to the proposed strength envelope(s) of Hawkesbury Sandstone derived using the Hoek-Brown and the spalling criteria. The ability of the Hoek-Brown rock mass strength criterion to differentiate between the ‘failed’ and ‘stable’ zones is considered to be remarkable.CITATION:Bertuzzi, R, 2014. Estimating the rock mass strength of Hawkesbury Sandstone, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference, pp 417–424 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 5, 2014

In 1972, metallurgical testwork on Renison ore indicated a significant proportion of low specific gravity, tin-barren material ideally suited to heavy medium separation (HMS). Further technical and financial studies provided adequate economic justification and in December 1974 the Renison HMS plant was cannissioned. Initial operations were interrupted by the imposition of tin production quotas for three months in 1976; they were also beset with difficulties particularly with regard to mechanical wear. During the first two operating years much develognent work was carried out including installation of a pyrrhotite flotation bank in the medium recovery circuit, investigations into various wear-resistant materials and the use of atanised rather than milled ferro-silicon. By 1977/78 financial year satisfactory performance had been achieved and since then the average floats rejection has been 18.8% of the total ore treated with an associated tin loss of 2.96%. Developnent has nevertheless continued during the last three years, principal modifications being the installation of larger aperture desliming screens and improvements to the overdense cyclone circuit.

Jan 1, 1978

By Duncan GR

Having passed through a number of previous phases the best longwall results in Australia have shown a significant increase in the last two years. The results expected from a longwall face can be estimated from the ideal production rate, determined by the capacity of the equipment and the conditions in which it is installed, the utilisation, and the available operating hours. Back analysis of the results achieved suggests that, on average, recent improvements arise from the higher capacity equipment recently installed; the utilisation has in fact reduced slightly. Review of the constraints which limit the longwall results, i.e. shearer speed, AFC capacity, support, advance rate, and man travel speed, shows that little improvement can be expected in the ideal production rate in thinner seams. In thicker seams the AFC often proves the overriding constraint and further increase in equipment size could lead to increased future ideal production rates and is expected. In all cases a concerted effort to increase the utilisation achieved is likely. For deep mines with thin to medium seams this offers the most viable path to improvement; by contrast thick seams with highwall/shallow access may benefit from further increase in equipment size.

Jan 1, 1988

By Ooms M, Scott OJ

This paper is concerned with the design and operation of storage and discharge facilit- ies for bulk solids handling. It presents an overview of the basic design philisophy emphas- ising the influence of bulk solid flow propert- ies and bin geometry on the flow patterns developed and how these, in turn, affect the reclaim efficiency and the bin structural in- tegrity and wear characteristics of both bins and chutes. The salient aspects of feeder design and operation will be discussed and the need to consider feeders as integral parts of the bin discharge system will be stressed.

Jan 1, 1978

By R Schiller, E Chait

"Quebrada Blanca is a porphyry copper deposit located in the Eocene-Oligocene belt of Chilean Andes. Operation started in 1994 and original reserves for supergene mineralisation gave a life-of-mine (LOM) of 20 years; however, further exploration extended the LOM until 2020.In order to optimise the remaining five years of supergene resource, geometallurgical variables were added to the geological model including copper recovery and acid consumption. LOM plan encompasses finishing the phase number eight and the future development of phases 11 and 13.LOM lithologies include diorites, quartz monzonites, porphyries, igneous and tourmaline breccias. Main alterations are: potassic, phyllic and argillic. Litho-alterations or geometallurgical units were formed by combining five types of rocks with three types of alteration. According to statistical information, the deposit can be represented with 12 litho-alteration units, which cover 98 per cent of the LOM volume.For copper recovery information, there were 40 mini-columns tests made in order to obtain kinetics curves and copper recovery values after comparing the difference between head and tails grades. Acid consumption was obtained using an automatic neutraliser device-based test.Historical data said that copper recovery in pads after 450 days of irrigation is around 75 per cent of recoverable copper while acid consumption is around 5.5 kg/t.According to this study, lower recoveries are related with potassic-altered diorites and argillic-altered quartz monzonites with values around 60 per cent. On the other hand, best recoveries could be found in potassic-altered quartz monzonites and argillic-altered diorites with values closer to 80 per cent.It was also revealed that the most reactive rock is the potassic-altered diorite with 12 kg/t of acid consumption. This rock covers approximately 40 per cent from phases 11 and 13.The final geomet model was calculated using a program that relates each geometallurgical unit with a specific copper recovery and acid consumption value. Results found after comparing model-obtained information with historical leached pads data were used to validate the model.CITATION:Chait, E and Schiller, R, 2016. Adding Copper Recovery and Acid Consumption Variables to the Geological Model of Quebrada Blanca, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 257–266 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By Daniels E. J, Morgan W. A

In response to the increase in consumption of galvanised steel for automobiles in the last decade and the problems associated with remelting larger quantities of galvanised steel scrap, a process is being developed to separate and recover the steel and zinc from galvanised ferrous scrap. The zinc is dissolved from the scrap in hot caustic using anodic assistance and is recovered electrolytically as dendritic powder. The dezinced ferrous scrap is rinsed and used directly. The process is effective for zinc, lead, and aluminum removal on loose and baled scrap and on all types of galvanised steel. The process has been pilot tested for batch treatment of 900 tonnes of mostly baled scrap. A pilot plant to treat continuously loose scrap, with a design capacity of 48 000 tonnes annually, has been in operation in East Chicago, Indiana since early in 1993. The first 450 t of scrap degalvanised in the pilot plant have residual zinc below 0.01 per cent and sodium dragout below 0.01 per cent. Use of degalvanised steel scrap decreases raw materials, environmental compliance costs, and opportunity costs to steel- and iron-makers. Availability of clean degalvanised scrap may enable integrated steel producers to recycle furnace dusts to the sinter plant and EAF shops to produce flat products without the use of high quality scrap alternatives such as DRI, pig iron, or iron carbide. Recycling the components of galvanised steel scrap saves primary energy, decreases zinc imports, and adds value to the scrap. The quantities of zinc available by the year 2000 from prompt and obsolete automotive scrap will approach 25 per cent of zinc consumed in the major automotive production centres of the world. Zinc recycling from galvanised steel scrap, either before or after scrap melting, will have to be Implemented.

Jan 1, 1993

Underground space can be defined as space below natural ground level which can be used as an alternative to an above ground location. While many of our above ground structures inherently involve underground excavation for foundations and services, the term underground space specifically refers to organised development of underground openings and of the underground domain. For example, the services to a city such as power, gas, sewerage, water and communications are installed in a congested array which usually requires roads to be dug up when the services need to be accessed. An underground space installation of services would involve a well planned conduit which is easily accessed without any excavation. The concept of using this virtually untapped land resource to the advantage of our expanding cities is gaining considerable interest in Australia. Overseas, in the Scandinavian countries and some Asian countries, underground space has been used for centuries; in Great Britain, France and the United States of America over the last century and in Japan for over a decade. This paper focusses on the types of underground space usage which should be competitive with above ground use and suggests areas in which the competitive edge may be improved in favour of underground space. In particular, considerable advantage is seen by using well-planned underground space developments in major cities, where the strategic central location of the development takes advantage of proximity to potential users. However, the largest single factor affecting the acceptance of underground space is the high capital cost of construction, even though an underground space development may result in lower operating costs and reduced long-term maintenance costs. While excavation methods and associated costs are very much site-specific, the importance of applying the latest technology in rock breakage, with consideration of ground vibration, excavation rates and ground support, remains a major challenge to the development of underground space.

Jan 1, 1995

By R L. Chaney, M Mahoney

Mine and ore beneficiation wastes and smelter contaminated soils often cause phytotoxicity and threaten adverse environmental effects if not remediated. Science has clarified both the risks from soil metals and methods to alleviate those risks that can be applied at low cost. Phytoremediation is a family of plant and agronomy based technologies to deal with environmental aspects of sites requiring remediation. If valid risk assessment indicates that metals comprise risk, phytostabilisation may be used to alleviate that risk for most contaminated sites. In particular, Zn-Pb, Cu and Ni mine and smelter sites are readily remediated by making the soil calcareous and fertile, with added organic and metal sorbent amendments that include soil microbes to ‘revitalise’ the soil. In each case, the soil fertility and causes of phytotoxicity should be clarified by agricultural soil extractions, and the combination of amendments required to improve fertility and reverse phytotoxicity identified and found locally. In contrast with phytostabilisation, phytoextraction/phytomining uses rare metal hyperaccumulator plants and agronomic management to maximise annual phytoextraction of soil elements into plant shoots for harvest, ashing and use as a metal ore. Plants that accumulate more than two per cent Ni in shoots, and yield 10–20 t ha-1 dry biomass yield 200–400 kg Ni ha-1, which has value greater than all common agricultural crops. Considering the value of elements, existence of hyperaccumulator plants and demonstrated agronomic management for Ni phytomining, it is clear that mine sites and Ni mineralised subore-grade serpentine soils can be phytomined economically as an agricultural mining technology. A team developed agronomic methods and improved cultivars of Alyssum, which can be profitably grown on temperate zone Ni mineralised or contaminated soils. Plant species for tropical ultramafic soil materials have been identified. Phytoextraction is also strongly needed to remove Cd from rice soils to prevent human disease from soil Cd.CITATION:Chaney, R?L?and?Mahoney, M, 2014. Phytostabilisation and phytomining – principles and successes, in Proceedings Life-of-Mine 2014 , pp 3–16 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By A Galli

Traditionally pit optimisation and scheduling is carried out assuming that the resources, the commodity prices and production costs are all known. Once the pit contour and the mining schedule have been determined, geostatistical simulations can be used to assess the impact of the uncertainty in the resources on the pit design and the schedule, and likewise stochastic simulations can be used to test its robustness to fluctuations in costs and prices. But it would be more interesting to have a dynamic procedure for optimising the pit as the resources become better known and as economic factors such as commodity prices and costs evolve over time. This paper presents a novel approach for doing this. Rather than working with millions of small selective mining units, it was decided to work with large blocks, called macro-blocks. Mining sequences are defined as the quantities to be extracted from each macro-block in each time period. Feasible mining sequences are mining sequences that respect the accessibility constraints, and also the geometric constraints on the amounts that can be extracted from any one block over time, or from all the active blocks at a given time. Having defined feasible mining sequences, their mathematical properties were studied. It was found that natural breakpoints occur in the sequences when one set of blocks have been completely mined out, thereby opening up access to others. It was discovered that families of sequences exist, and that they are convex and closed under certain types of row permutation operations. Convexity is an advantage when optimising. The closure property opens up the possibility of mixing and matching subsequences of rows in the sequences. Another interesting property is that the sequences form branching families, rather like the binomial and trinomial trees used to model prices in finance and in real options.It is easy to generate large numbers of feasible mining sequences randomly. A two-step procedure is used to find the best one (or the best few) using three economic criteria: expected NPV,the probability of a negative NPV, and the percentage of years when the cash flow is negative. The procedure was tested on a synthetic gold mine based on the characteristics of the Essakane mine in Burkina Faso. The results were encouraging.

Sep 26, 2011

By I Swane, R Rait, A Robertson

Geochemical assessment of mine waste materials prior to commencement of a proposed mining operation is a fundamental component of mine feasibility studies and the regulatory approvals process. Static and kinetic geochemical test methodologies are widely used to predict the geochemical nature of mine waste materials and to develop strategies for managing potentially æhostileÆ materials. These data can also be integrated with data from other fundamental studies such as hydrogeology to predict specific environmental outcomes and potential impacts at mine closure and post-closure.A case study is presented for a proposed open pit gold mine in Mongolia, which illustrates how geochemical, hydrogeological and groundwater quality data can be used as part of a geochemical modelling process to predict the final pit lake water quality over time. A series of static and kinetic test geochemical test programs were completed and acquired data integrated with hydrogeological and groundwater quality data provided by the proponent. A widely used geochemical modelling program (PHREEQC) was used to develop the geochemical model and predict water chemistry in the pit void after mine closure. Sensitivity analyses were completed to explore the effects on the model output of groundwater to leachate water ratio, pit wall rock type and climate.Modelling has indicated that pit void water should be pH circum-neutral at mine closure and should remain within Mongolian and World Bank water quality guideline limits under the modelled simulation most likely to occur in the field. Final void water salinity is expected to increase eight fold over 14 years after end of mine life due to a continuous flux of salts (particularly sulfate salts) into the pit lake whilst the pit lake volume will remain relatively constant due to evaporation and a slow recharge rate. Dissolved metal and sulfate salt concentrations in pit water are also predicted to increase over time and could be moderately elevated compared to applied water quality guideline values. Some of the metal concentrations, however, may be lower as these would be expected to precipitate at circum-neutral pH and greater. Recommended additional assessment work on the project when mining commences includes determining the magnitude of adsorption and co-precipitation of metals occurring in the pit void water/sludge system.CITATION:Robertson, A, Rait, R and Swane, I, 2013. Geochemical assessment of mine waste materials and prediction of final pit lake water quality at a proposed gold mine in Mongolia, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 165-170 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

By M Norbert, C Bennett

The Legacy Way Tunnel was constructed from Toowong to Kelvin Grove in Brisbane, and is the first large-scale underground excavation in the Bunya Phyllite in Brisbane. The Legacy Way Tunnel is 4.3 km in length, comprising two mainline tunnels excavated by a tunnel boring machine (TBM) with 46 connecting passages excavated between the mainline tunnels for egress provision and services. The Legacy Way Tunnel passes through two geological formations, the Bunya Phyllite and the Neranleigh Fernvale Beds. The Bunya Phyllite is the dominant formation of the Legacy Way Tunnel, extending for three quarters of the tunnel prior to intersecting the Normanby Fault Zone (NFZ) and the Neranleigh Fernvale Beds. The NFZ forms the contact between the two formations as part of the Brisbane Metamorphics, which underlies the majority of Brisbane City. The development of the geological model and the understanding of the ground’s reaction to tunnelling was an iterative process. The tender phase investigation data has been supplemented with additional design phase investigation boreholes, geophysics and walk overs. Aerial photograph interpretation coupled with borehole data allowed the development of the domains along the length of the tunnel. Early excavations for the spoil conveyor tunnel and borehole data from subsurface instrumentation installation provided the first construction phase data followed by the commencement of tunnel boring machine (TBM) excavation. Routine cutterhead inspections coupled with ongoing reviews of the predicted geology resulted in clear response triggers to selection of segment types while detailed inspections in passage locations provide the initial classifications for segment removals.CITATION:Bennett, C and Norbert, M, 2014. Tunnelling within the Bunya Phyllite of Legacy Way, Brisbane, Queensland, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 131–140 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

Underground mining in the West Moreton coal field started in the 1870's. Subsidence related to coal mining activities is an ongoing problem facing planners and developers in the Ipswich area in South Eastern Queensland. The history of coal mining in the area over the last 110 years has left the legacy of periodic surface instability in several areas. In general, modern engineering analysis with current mining methods combine to create predicatable analysis of surface stability and movement. Where old workings using several variations of the bord and pillar system are affected by current activity, the predictibility of the surface movement is greatly reduced. Geological complexities further complicate the analysis. Mining and the related dewatering affects the stresses on pillars in old workings. This is caused by reducing buoyancy effects caused by changes in the water levels in old workings. Of particular relevance is the depth of workings and strength of the coal and overburden. The type of subsidence affecting the surface can range from localised pillar failure, to roof failure and potholing and the likelihood of the particular form of subsidence can be assessed from studying the workings in relation to the stratigraphy and structure of the coal measure Formations.

Jan 1, 1988

By J E. Everett, K Jupp, T J. Howard

Simulation modelling is a practice commonly used in the mining industry to evaluate alternative process designs. Such modelling is typically undertaken as an optimisation study to increase the efficiencies, productivity and product quality of operating mines. In this situation, real short-term grade variability data of extracted ore are available from production records as input data into the simulation.There is also a need for simulation modelling to be performed before mines are approved for construction to clarify the grade variability characteristics that can be expected from the operating mine and assist in the optimisation of the process design. In this situation no historical short-term grade variability data are available. To achieve meaningful and reliable results from a simulation it is necessary to have input data for the ore to be extracted from the pits, representative of the short-term grade variability that would be expected for the operating mine.This paper describes an example of a path taken to generate realistic input data.A method described as composite cut-off criterion was used to distinguish ore from waste, which gave substantially greater recovered tonnage at target grade compared to the conventional quadrant cut-off grade criteria.The only data available for the project was resource model data in the form of kriged block models, which are known to underestimate true ore grade variability. To achieve realistic results from the simulation it was essential to increase this variability while maintaining the accurate average grades. Areas of certain deposits that were modelled using both kriging and conditional simulation estimation techniques were quantitatively compared to establish the comparative variance and the kriged data was modified to match the conditionally simulated variance.A realistic mining model was generated via a process of discretisation and regularisation of the resource blocks. Quantitative assessment demonstrated that this method adequately compensated for ore dilution and that adjustment for ore loss was not required due to an ore skin surrounding the edge blocks.The conditioned data was then used to generate a schedule of daily mine extraction, considering grade variability, tonnage, equipment constraints and extensive blended-in-blended-out precrusher stockpiles to feed into the process design simulations.For the precrusher stockpiles a number of alternative allocation criteria were examined for ore being extracted from the pits to identify the best method in achieving reduced variability through the daily scheduling system. The study concluded that a single analyte separation criterion produced acceptable variability with minimal complexity.The blending efficiency of manually stacked and reclaimed precrusher stockpiles was studied to determine a realistic blending efficiency within the pile. A recommended method of building and reclaiming was determined to give maximum blending efficiency.Finally, the data was used as input into process design simulation models; simulation from crusher feed to shiploading demonstrating that control of shipment grade variability was achievable and that the conditioning of the data delivered realistic results.CITATION:Jupp, K, Howard, T J and Everett, J E, 2013. Generating synthetic data for simulation modelling in iron ore, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 231-238 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

By Pak DL

Over the last decade computers have become an essential element in assessing the economic feasibility of mining new mineral deposits and in assisting a variety of related support functions. A broad overview is given of the many technical application areas where computers are contributing to the mining industry with reference to work being done on the evaluation of drill hole information, mineral inventory modelling, ore reserve estimation, financial analysis, process simulation, process control, workshop job scheduling, PERT applications, and com- puter aided drafting. In all these areas the computer has greatly reduced the manual effort involved in looking at alternatives. It has had a significant effect in eliminating delays in revising calculations, or rescheduling activities to incorporate new data or cater for changing conditions, while at the same time providing more accurate and prompt information for the management decision making Process.

Jan 1, 1980

By M Svartsjaern, D Saiang and K Mäkitaavola

The Kiirunavaara mine is a large-scale (28 Mt/a) iron ore mine located in northern Sweden. The mine is owned and operated by Luossavaara-Kiirunavaara Aktiebolag (LKAB) using sublevel caving (SLC). The SLC area underlies an open pit decommissioned in the 1950s, the current main SLC haulage level is situated at an depth of 1100 m. The main orebody dips 60 degrees to the east with a distinct boundary defining the hanging wall to the east and footwall to the west. Since the 1980s damage has been observed both in the footwall rock mass as well as on the footwall crest of the open pit. Recent investigations indicate that the underground footwall damage is primarily controlled by large-scale slope failure mechanisms. Structurally controlled near-vertical planar shear failures in the upper footwall appear to be driven or facilitated by a step-path like curved shear failure situated in a zone starting ca 250 m, and intersecting the SLC about 100 m above the active mining level. To confirm this failure evolution a pilot underground measuring system has been designed and installed to monitor the expected rock mass displacements indicated by numerical models based on the above mechanisms. The systems consists of 50 m time domain reflectometry (TDR) coaxial cables installed in the footwall both across and away from an estimated damage extent boundary to monitor shear movements along natural joint surfaces. The TDR installation is combined with long extensometers to facilitate differentiation between diffuse shear and rock mass normal expansion. Additionally, a low-tech system of tape extensometer lines are installed in drifts and stopes running perpendicular to the ore strike to monitor horizontal displacements in the infrastructure as the footwall ‘slope’ loses confinement during mining advance when the mined out areas are replaced by caved rock from the hanging wall.CITATION:Svartsjaern, M, Saiang, D and Mäkitaavola, K, 2016. Underground footwall monitoring at the sublevel caving mine – Kiirunavaara, Sweden, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 773–780 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By J Cook

In this paper we present a case study of the challenges and opportunities associated with the development of cultural heritage management strategies at the Lihir gold mine in Papua New Guinea. We discuss the contextual drivers and constraints, and outline the ways in which Lihir Gold Limited is aiming to set new industry bench marks for the region through the development of values-based best practice cultural heritage management programs. This approach is largely based upon a compliance partnership with a local stakeholder group. We argue that such partnerships are a prudent means of mitigating company risk, while constituting a far more necessary tool for local people in the reconceptualisation and negotiation of the experiences of significant social change and modernisation experienced in the context of recent resource development.

Jan 1, 2009