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By D H MACKENZIE

In common with several great orebodies and mineral camps around the world Broken Hill has been the subject of state-of-the-art technical and scientific scrutiny during its long working life. During the early years geological interest in Broken Hill tended to be directed at the body for its intrinsic scientific worth, mainly on account of its large size, high grade and wealth of mineral species. For much of the last 60 years the interest has had a more applied motivation, namely, to assist the search for either repetitions in the Broken Hill field or analogues in other terrains. This paper looks at the major changes in geological concepts and exploration techniques applied at Broken Hill and attempts to assess their impact.

Jan 1, 1992

By P Alspach, R Buxton, C Morgan, C Ross

Mining companies worldwide have an increasing interest in restoring indigenous ecosystems following mining. Low levels of plant nutrients and organic matter, pH extremes, heavy metals, physically challenging media, and difficult climatic conditions all hinder revegetation of steep rockdump slopes. Our techniques use colonising pioneer plants to accelerate natural soil development and plant succession processes on minesites that are difficult to revegetate with locally sourced plants by traditional techniques. Suitable treatments and pioneer species must first be identified for each rocktype. Field trials at the Stockton Coal Mine in Buller have shown that successful acceleration of moss and pioneer plant establishment is possible. Best plots showed a mean of 15 per cent moss cover and 3.3 per cent vascular cover after 12 months compared with 0.1 per cent and nil respectively for controls. Techniques have been extended to field-scale trials, using hydroseeders and dryblowers. These techniques show potential for practical land rehabilitation, whilst conserving local biodiversity.

Jan 1, 2003

Remote sensing techniques can be used to map joint sets in a rock mass for the estimation of in situ block size distribution and improved optimisation of blasting. This paper reviews remote sensing using photogrammetry and laser mapping for mapping rock masses and presents elements of the analyses applied to data acquired with these mapping technologies. These techniques enable a user to map areas of hundreds of square metres rapidly with high precision. Using this data computer programs such as Sirojoint can provide estimates of joint position and orientation with orientation measurement accuracies better than one degree. The paper describes the use of remote mapping and provides potential users with a description of some of the advantages and limitations of the mapping techniques and the data they produce. Mapping of lithology and structure of rock masses is an important task required in many areas of mining and construction. It is a complex task routinely performed using established techniques developed to provide consistent results under a wide range of conditions. The techniques for data acquisition and analysis described in this paper enable more accurate mapping to be performed rapidly and enable mapping of inaccessible sections of a rock mass. These techniques will provide geologists and geotechnical engineers with more detailed, accurate data than previously available.

Jan 1, 2001

By J Purandare, D Murdoch

The goal of the life-of-mine plan is to ensure that while the site is left safe, stable and non-polluting, the landscape is such that optimal use can be made of the site post-mining and closure. However, in the face of evolving shareholder expectations and the current international economic climate, numerous mines are ceasing operations and moving into a care and maintenance phase. These changes bring with them a high degree of community concern, not only about the potential legacy of closed operations, but also those mines that continue to operate.While mines across Australia are committed from the earliest planning stage to develop clearly defined post-mining land use and landform objectives, broader expectations related to these objectives may change and evolve during the life of the operation. This is especially the case where a mining operation has a project approval where the land use objectives are aligned to land capability and land use commensurate to that which occurred premining. CITATION:Murdoch, D and Purandare, J, 2016. Optimising land for beneficial use during and after mining, in Proceedings Life-of-Mine 2016 Conference, pp 166–167 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By N TassT, J Cyr

At the East Sullivan site, wood wastes covering the abandoned mine tailings impoundment prevent sulfide oxidation by creating an anoxic environment. The addition of coarse ligneous wastes and their high permeability favour infiltration, resulting in a water table rise that maintains most tailings under water saturation and thus provides an additional protection against sulfide oxidation. Moreover, high infiltration allows a more rapid flushing of acid prone groundwater generated prior to the cover placement, which could cause acid mine drainage over a long period of time. Finally, the pore-waters under the cover are characterised by a strong reducing potential, high alkalinity, and near neutral pHs. These conditions favour sulfate reduction and base metal precipitation as sulfides and as carbonates. Pore-water composition monitored from 1992 to 1998 showed a significant Fe2+ decrease, following cover placement. Thereafter, the restoration strategy capitalised on the alkaline and reductive properties of the waters underlying the wood-waste cover. An original treatment of acid effluents, based on the recirculation of water discharging around the impoundment through the organic cover, was implemented. In 2002, the recirculated water from May to October had a mean pumping rate of 240 m3/h, for a total volume of 800 000 m3. Data gathered near the dispersal zone from 2000 to 2002 show that despite the recirculation of acid water (pH ÿ3), the pH decreases by only one unit from 7 to 6, during the recirculation period, ie from May to November. However, alkalinity decreases from 800 to 100 mg/L-CaCO3. Despite this decrease, the alkalinity is back up to 800 mg/L-CaCO3 the following May, thanks to sulfate reduction. From 2000 to 2002, Fe2+ concentration in the pore waters near the dispersal zone is maintained below 2 mg/L. Evolution of surface water quality suggests that the contaminated groundwater flush is completed in the north and north-west area of the impoundment; the east sector is under recovery, while the south sector remains the most problematic. A wood-waste cover, besides limiting sulfide oxidation, can fill the role of alkaline reducing barrier for the treatment of these acidogenic waters, until a balance between acidity and alkalinity in the effluent is reached.

Jan 1, 2003

By J Jones, J Blunt

"The requirement for environmental approvals and associated environmental impact assessments (EIAs) is now commonly regarded as a key milestone and body of work during project development. EIAs can be undertaken at various phases during project development, generally either:\ during the scoping or prefeasibility studies, where limited project information is available and the mitigation and management measures of the EIA become a set of criteria and commitments that control project design during the feasibility study, as an iterative approach whereby mitigation and management measures are developed through an integrated process with the engineering team, and measures are included in the feasibility study cost model following the feasibility study, where detailed project design information is available, the cost model is complete, and the EIA is an assessment of a fixed project with limited opportunities for mitigation and management measures to be integrated into engineering design. This paper investigates the advantages of integrating EIA into life-of-mine planning during the feasibility study phase, using the Tampakan Copper-Gold Project (the Project) as a case study. The Tampakan Project is located in the Philippines on the southern island of Mindanao. The Project involves the proposed development of three main areas of infrastructure:a large-scale, open pit copper-gold mine and associated mine site infrastructure (including tailings and mine waste storages, fresh water dam, concentrator, etc) a power station, port and filter plant (PPFP), located approximately 60 km from the mine a pipeline and transmission line linking the mine and PPFP sites.Examples of engineering measures developed through an iterative process to mitigate and manage predicted environmental and social impacts include design of water management infrastructure, modification of the disturbance footprint (eg roads realigned to avoid critical habitat) and realignment of project infrastructure to minimise impacted water catchments.CITATION:Blunt, J and Jones, J, 2012. Integrating environmental impact assessment into life-of-mine planning, in Proceedings Life-of-Mine 2012 , pp 143-152 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 10, 2012

The implementation of robust, reliable and accurate sampling systems is the key to the successful management of any mineral processing plant. The representative sampling of a mineral processing plant is the only way to determine what is coming into the plant, what is going out as fi nal product and what is going to tails. In plants with high gravity gold components, where high recovery effort gravity circuits are installed, the use of a gravity recoverable gold (GRG) sampling system can assist in the online monitoring of the performance of the circuit. The typical installation location would be in CIP or fl otation feed (ie cyclone overfl ow), downstream of the gravity circuit. A GRG sampling system generally consists of the following equipment: true proportional, continuous drive, linear cross cut sampler, secondary vezin sampler operated on a timer, a batch centrifugal concentrator, and sample dewatering module. The operating philosophy of the GRG sampling system is that the primary sampler operates on a continuous basis, generating a constant stream of truly representative sample. Consep's H&S drive system is unique in its ability to be able to operate in a continuous mode, therefore enabling a continuous stream of representative sample to be generated. The primary sample stream reports to the secondary sampler. The secondary sampler operates on an intermittent basis (nominally ten minute interval), resulting in a relatively small sample volume per shift. Normally the sample volume would be ten to 15 L per shift. The secondary sample rejects stream reports back to the batch centrifugal concentrator. The sample generated from the secondary sampler can be dewatered using a Consep H&S dewatering module. This device produces a final sample that consists of separate filter cake and filtrate. These are suitable for taking directly to the laboratory. The continuous stream of truly representative secondary sampler rejects is passed through an appropriately sized Knelson Concentrator, typically a KCMD7, KCCD10 or KCCD12 sized unit. This unit recovers any available GRG from the stream. The Knelson Concentrator is also purged of its gravity concentrate at the end of the shift. This sample, which is nominally around 1 - 2.5 kg of concentrate, is also taken to the laboratory. At the end of the shift the client will have a measure of the gravity recoverable gold content of the target slurry stream, as well as a true representative sample of the complete stream. Through the addition of a Knelson Concentrator to an otherwise typical sample station, it is possible to generate a true measure of the performance of your gravity circuit. This will take the guess work out of the daily variation in gravity circuit gold recovery, as the site knows whether the changes are due to gravity circuit equipment performance, or due to the natural variation of ore GRG contents. Maintenance planning can also be designed around the system, as the site will have a composite sample to measure the performance of the circuit, therefore indicating where performance has dropped and maintenance is needed. This is an ABSTRACT ONLY. No paper was prepared for this presentation.

Aug 1, 2010

By D Phillips

One of great challenges is to determine the exact timing of gold mineralisation in centralVictoria due to suitable materials and/or geochronological techniques. Here we report new mica and pyrite 40Ar/39Ar age data by laser probe and step-heating furnace analyses, and discuss problems in data collection and interpretation. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

Flue gases from electrical power station boilers, roasting, metallurgical and chemical plants could be treated by flotation using conventional flotation machines. The flue gases are introduced into the pulp instead of the air. The flotation media is a suspension of Ca(OH)2 or CaCO3 or a solution of NH4OH etc containing Na oleate as collector and frother. The SO2 and dust content of the initial flue gases were experimentally reduced by 100 to 1000 times in one flotation operation. The velocity of the flue gases through flotation machines could reach approximatively 0.4 to 0.5 m/s and more against 1.5 m/s reached in scrubber absorbers used for this purpose, but the quality of purification is expected to be better for flotation, which is essential for the cases of heavy polluted metallurgical and chemical flue gases. For some chemical plants the flue gases flotation media may be different and more suitable as compared to the above mentioned media. The proposed flotation method could be used for separation of dry grinded ores in the form of aerosols, with a realisation of flotation from a closed space (gas bubble in the pulp) onto the interface liquid-air where the particles are attached inside the bubbles.

Jan 1, 1993

The Department of Conservation (DOC) manages public conservation land throughout New Zealand in terms of section 6 of the Conservation Act 1987. In brief, this requires DOC to manage the natural and historic resources of the land; promote the benefits of conservation to present and future generations; provide information about conservation; to foster recreation on the land; and allow for its use for tourism.   Locally the department's Tauranga Area Office manages approximately 60 000 hectares of Conservation Park (known as the Kaimai-Mamaku Forest Park) which includes early gold mining relics and former bush tramways associated with the logging and the mining industries. The Department has recently developed the Kaimai Heritage Plan which seeks to restore some of the relics and encourage involvement by the local communities in the restoration and interpretation of their history in the hills. It provides a unique opportunity for the Department to help bring alive for New Zealanders an important, and often overlooked, part of our history as a nation in a stunning natural setting.   The purpose of this presentation is to: +        display the endeavour and ingenuity of the early miners and loggers, the relics of those industries and the dramatic environment in which they worked; +        identify the linkages between those early industries and gold mining today; and +        promote a co-operative approach to heritage and recreation management involving all facets of the community.

Jan 1, 2006

By Bucknell WR, Clarke DE

The paper provides a company's view of the relative merits of various valuation methods and outlines the basic approach it takes to the valuation of an exploration property. The negotiating process and methods of acquiring an interest in an exploration property is discussed The valuation methods discussed are: 1. Exploration Expenditure. 2. Real Estate. 3. Joint Venture Terms. 4. Rule of Thumb. 5. Net Present Value - Discounted Cash Flow. 6. Geoengineering.

Jan 1, 1994

Escondida is a state-of-the-art copper mining operation. It is the major copper project of the 1990s and is the largest new investment in the industry - a US$823 million project. It accounts for about six per cent of Chile's total exports, making Escondida the largest private exporting company in Chile.

Jan 1, 1992

By L S. Barbour, M K. Meiers

Soil covers for mine waste are subject to changes in structure as a result of root development, and wet/dry or freeze/thaw cycling. The purpose of this study was to evaluate the changes in the hydraulic conductivity of three non-compacted clay covers over time. The covers are located on a sodic/saline overburden fill (30-Dump) at the Syncrude oilsands mine in Fort MacMurray, Alberta, Canada. Monitoring of these covers for temperature, matric suction, and water content by the University of Saskatchewan has been ongoing for more than three years. The three covers (D1, D2, and D3) were constructed in 1999 and are 50 cm, 35 cm, and 100 cm thick. The covers are comprised of a surface layer of reclaimed peat/mineral mix over a secondary reclaimed mineral soil (glacial till or glaciolacustrine clay), placed over a sloping shale surface. Field measurements of hydraulic conductivity within the secondary layer were obtained using a Guelph Permeameter during the 2000, 2001, and 2002 summer field seasons. Repeated measurements were made within the D1, D2, and D3 covers at depths of approximately 40 cm, 30 cm, and 60 cm, respectively. The values of hydraulic conductivity for the covers were similar to each other during each of the field study seasons. The mean hydraulic conductivity of the secondary layer increased every year: 2.5 + 10-6 cm/sec to 2.1 + 10-4 cm/sec to 4.3 + 10-4 cm/sec from 2000 to 2001 to 2002. Soil temperature data shows that one freeze/thaw cycle occurred each year at the measurement depths.

Jan 1, 2003

By J A. Rumball

Measuring cyanide in the leach liquors associated with high copper and/or sulfide ores is a non-trivial exercise. It is well known that copper complexes with cyanide and reduces the amount of cyanide available for gold leaching. What is not so well known is that the rhodanine end point overestimates the amount of cyanide available for leaching in the presence of copper. Sulfide ions also interfere with a rhodanine end point titration, although this is less of a problem as the black silver sulfide precipitate formed clearly indicates to the operator that something is wrong. Thiosulfate, which forms readily from the alkaline oxidation of sulfides, causes an overestimation of the cyanide available for leaching due to the formation of Ag(S2O3)-. The net result of these observations is that rhodanine is rarely of value as an end point indicator in complex solutions. It generally overestimates the amount of cyanide available, providing plant metallurgists with a false sense of security. Potentiometric titrations are generally much more capable of accurately measuring cyanide in complex solutions. The interfering effect of copper can be resolved and it is even possible to estimate the copper concentration using the inflexions associated with the titration of CN- + Cu(CN)43- versus Cu(CN)32-. Using the potentiometric method sulfide ions can be determined before the cyanide measurement is made due to the formation of AgS2, although the electrode will foul with repeated measurements. Thiosulfate can also be distinguished from cyanide with a potentiometric titration. Rhodanine and potentiometric titrations are both affected by the pH of the liquor. At pH 9.2 half the cyanide will be present as CN- and half as HCN(aq) with only the CN- being titratable. This does not hold in the presence of a buffer active around pH 9. In the presence of sufficient buffer, both the CN- and HCN(aq) are titrated. Ca(OH)+ may buffer the pH when large amounts of lime have been added.

Jan 1, 2007

The JORC Code, which has been in existence as a Code incorporated in the listing rules of the Australian Stock Exchange and New Zealand Stock Exchange since 1989 and 1992 respectively, has been revised and will be re-released in 2003. This revision followed a call for submissions in December 2001, the publication of an exposure draft in late-2002 and an exposure period during which a large number of constructive comments were received. These comments were reviewed and a further exposure draft released as part of the current exposure draft of the ASX listing rules. It is anticipated that the final Code will be incorporated into the stock exchanges listing rules in late-2003. The 1999 JORC Code has been the standard on which other reporting Codes have been based, each of which has contained refinements. Three in particular, the Reporting Code from the United Kingdom/Ireland/Western Europe, the new Canadian Reporting standards and the SAMREC Code from South Africa, influenced JORC in the preparation of the 2003 JORC Code. Whilst there are differences between the 1999 Code and the 2003 Code, these changes are mainly in the guidelines. The Code definitions, which are largely in accord with agreed international definitions, remain substantially unchanged. The two main changes in the 2003 Code are the requirement for a Competent Person to be responsible for the documentation relating to the reporting of Exploration Results, and the introduction of æRecognised Overseas Professional OrganisationsÆ as overseas organisations to which Competent Persons may belong. Other changes include: clarification of the reporting of exploration targets or potential; the rearrangement of the diamond reporting clauses; the introduction of guidelines for the reporting of Industrial Minerals; modification of the coal clauses and recognition of the new Coal Guidelines; and the introduction of a guideline encouraging the discussion of relative accuracy and confidence in resource/reserve estimates. Other lesser changes to the Code are listed and discussed briefly. The release of the 2003 JORC Code maintains the standard set by JORC as a world leader in the development of mineral reporting Codes and their adoption by industry.

Jan 1, 2003

Australia is a significant exporter of uranium for use as fuel in nuclear generating plants around the world. Although Australia does not have any nuclear power plants the Australian Atomic Energy Commission has a research program on methods for the safe disposal of wastes produced by such plants.

Jan 1, 1986

By M Chiquito, R Castedo, P Segarra, L M. López, J A. Sanchidrián, J Navarro

The aim of this work is to assess the performance of different constructive solutions against explosions on the strength of masonry walls. The solutions tested, namely an external metal mesh, a glass fibre film on the external face of the wall and a basalt fibre film located on the inner face of the wall, have low to medium cost and are originally designed for other purposes, like seismic protection. Four cubic boxes 3 × 3 × 3 m were built using each of the solutions and typical masonry blocks. In the tests, a spherical plastic explosive initiated in the centre was placed at scaled distance of 2.9 m/kg1/3, so that moderate damage would be caused on the wall. In order to assess the performance of the explosive, pressure gauges were placed at the wall and at different distances from the explosion. Additionally, vibrations were monitored with seismographs in the far field and a high-speed camera was used to estimate the shock wave velocity during the tests. The resulting damage has been evaluated on 13 points of the external wall of each box using a rebound hammer. Damage maps have been drawn for each wall based on these measurements and damage has been assessed inside the box considering the fragments mass launched during the test. The use of external metal mess leads to a decrease of 34 per cent on damage of the external wall and 38 per cent reduction of spalling. The use of a film in the inner wall provides a strong reduction on spalling.CITATION:López, L M, Segarra, P, Castedo, R, Sanchidrián, J A, Navarro, J, Santos, A P and Chiquito, M, 2015. Performance of different constructive solutions against explosions in full-scale masonry walls, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 819–824 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

This paper discusses how the i-kon TM Digital Energy Control System may be deployed by miners of massive underground orebodies to deliver significant advantage in terms of safety, cost and environmental compliance. Digital Energy Control offers an exciting opportunity for mine operators to review their blasting and mining practice to gain the most advantage from this new technology.

Jan 1, 2000

By G Wood, B Lumsden

A statistical ærandomised block designÆ full plant trial of magnetic conditioning of flotation feed was undertaken at Rio TintoÆs Northparkes Mine in New South Wales. Magnetic conditioning of flotation feed has been shown to improve the flotation of 20 38 ¦m fraction for either metal. Approximately half the copper and gold losses at Northparkes are in the

Jan 1, 2007

By C OÆKeefe, A Thomas

Boom time in the mining industry has presented mill operators with several unique challenges including the need for increased throughput while being constrained by a shortage of skilled labour and aging capital equipment. New instrumentation technology that provides reduced installation costs; no process down time for installation; and reduced maintenance costs and labour requirements; has been introduced to address the labour situation while maintaining production. This new tech- nology also enabled more accurate and reliable process measurements thus providing the capability for operators to maximise throughput with their existing capital equipment. This passive SONAR based technology can accurately measure the volumetric flow rate of single phase and multiphase fluids as well as the amount of air entrained within slurries. This is accomplished in a non-invasive manner. This paper will describe the principle of operation as well as the application of the technology to critical minerals processing applications. Included will be operational examples comparing the SONAR measurement performance to traditional measurement techniques. These examples will include hydrocylone feed flow, flotation concentrate flow, and slurry streams containing magnetic ores. Actual plant data will be presented as well as a discussion on the operational advantages such a measurement capability.Also described will be the power of the technology platform to provide novel process monitoring and control capabilities such as pipeline sand-out prevention and pipeline acoustic monitoring.

Jan 1, 2009