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By P B. Swart, P D. Erskine

Despite an increasing focus by media, communities and activists driving an elevated regulatory focus in Australia and indeed some other mining jurisdictions, the mining industry globally has had limited successful mine lease relinquishments and transfers to support a next land use.Critique from anti-mining lobbyists frequently uses the large estimates from historically abandoned mine sites to influence risk-averse regulatory reforms to improve environmental performance. The mine rehabilitation regulatory processes in Australia, and specifically in the State of Queensland, are thus largely in place to prevent mining operators from abandoning their obligations.Regulatory responses to the lack of mine rehabilitation and closure performance in the last five to ten years have primarily focussed on compliance and enforcement of rehabilitation conditions in environmental approvals. Additionally, financial assurance measures have been tightened to protect against abandonment of rehabilitation obligations by the Industry, including the Chain of Responsibility legislation (Queensland Government, 2016b) in April 2016, to hold to account those who have benefitted from mining and processing/refining projects, and then avoid their environmental obligations.CITATION:Swart, P B and Erskine, P D, 2018. Are our closure planning and regulatory processes adequate to identify, quantify and appropriately transfer residual risks after successful mine rehabilitation?, in Proceedings Life-of-Mine 2018, pp 155–158 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By G R. Hancock, J F. Martín Duque

Post-mining landscapes are required to geomorphologically and ecologically integrate with their surrounds (Martín Duque et al., 2015). Designing and constructing an erosionally stable landform is the first and arguably most important part of the rehabilitation process. Without an erosionally stable landform topsoil and nutrients are lost, shallow groundwater is depleted as well as when excessive erosion occurs, expose suboptimal materials. Here we examine the ideas of geomorphic design and rehabilitation and how the landform can be tested and enhanced using computer based design and landscape evolution models. Specifically we evaluate the complementary capabilities of landscape modelling (SIBERIA) (Hancock and Willgoose, 2017) and geomorphic design software (Natural Regrade with GeoFluv) (Bugosh et al., 2016), in order to maximise erosional stability on post-mining landscapes (Zapico et al., 2018). CITATION:Hancock, G R and Martín Duque, J F, 2018. Geomorphic design and landscape evolution modelling for best practice mine rehabilitation, in Proceedings Life-of-Mine 2018, pp 119–121 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

THIS excellent volumetric method commends itself as a means of estimating the fineness of silver firstly, owing to the large number of possible impurities which do not affect its accuracy (these impurities include Cu-up to 70 % Au, Ph, Zn, Bi, Cd, Fe, Mn, Sb, and As); secondly, the method combines accuracy with speed. The above impurities are the only ones likely to be present in the B. H. A. S. Pty. Ltd. refined silver, and, with the exception of Cu and Au, the others, if present at all, would be well under 0.1 parts per 1000.Briefly stated, the method consists in the solution of the refined silver in HN03 , addition of ferric alum (indicator), and titration with an alkaline (either ammonium or potassium) thiocyanate solution until the brown ferric thiocyanate is formed, and gives a definite tint to the solution. The method is used at the Port Pirie smelters, and the outstanding feature in the method as there applied is the type of burette employed. This burette enables the operator to read 0.01 of a cc. with ease, whereas, with the ordinary burette fitted with a float, 0.05 of a cc., when a number of readings have to be taken, becomes very straining to the eyes. Moreover, waiting for the float to rise, and dislodging air bubbles from it, hinders rapid working.A description of the burette and fittings is appended with fig. 2. DETAILS OF THE METHODSolutions required are:a) Stock Solutions:(1) Ammonium thiocyanate, 40 grm. per litre of water; 30 litres are prepared and placed in a carboy with glass syphon attached.(2) Ferric alum, 250 grnl. per litre; two litres are prepared.

Jan 1, 1922

The Melanesian Outer Arc, extending from. Papua New Guinea to Fiji, developed as a result of interaction between the Australian and Pacific plates throughout the Tertiary, and the following stages are recognized. ,a, Formation of island arc tholeites above a west facing subduction zone in the Lower Tertiary. fit Emplacement of mainly calcalkaline volcanics above an east facing subduction zone in the Upper Miocene and Pliocene. ontinued east facing subduction coupled with fragmentation of the arc from the Pliocene onward. Alkaline and Mg-rich volcanism occurred in addition to continued calcalkaline activity. Tre Upper Miocene and younger volcanism is into five arc segments on the basis of geographic position and nature of the magmatism. The calcalkaline Bismarck arc extending along northern New Britain and including small islands to the west. The alkaline Tabar to Feni arc, north of New Ireland. The Solomons arc, including Bougainville and the western part of the Solomon slands. Volcanism is largely _.alcalkaline, but Mg-rich varieties occur the Solomon Islands. roe New Hebrides arc, extending from the -astern Outer Islands of the Solomons through Vanuatu. Both calcalkaline and :alkaline volcanics are representeo. alkaline and calcalkaline Fiji arc.

Jan 1, 1987

The carbon-in-pulp (CIP) process is now well established in the South African gold industry, with a total of over I million metric tons of material being treated each month in six large plants. This tonnage is derived from ground ore, from filtered pulp, from calcine, and from reclaimed sand-tailings dumps. With this new process and the new large plants, those concerned with CIP are experiencing a learning process, since each new plant presents a different set of problems to be overcome. The knowledge and experience gained from these plants is being shared, and will be of benefit in the design and operation of new plants. The CIP process can be subdivided into the following unit operations: prescreening at a fine size, adsorption, acid-washing and elution, reactivation, and electrowinning. Results concerning each of these unit operations, which were obtained from pilot plants and from large-scale CIP plants in South Africa, are presented. The latest developments in each of these areas is summarized. Tables that are included as an appendix contain some information concerning the equipment in these new CIP plants plus operating results from some plants.

Jan 1, 1982

By M D. Taylor, G Duclaux, K Atkinson, L A. Fisher, A R. Latham, M F. Gazley, S J. de Beer, C M. Tutt

Geological logging by mine and exploration geologists involves the application of a logging code that requires a geologist to make a subjective decision to classify a particular rock unit. This will most likely result in inconsistencies in logging that will be difficult to monitor or assess over time. A potential solution to this problem is to have an objective method to determine the true nature of a given rock unit. This can be achieved using portable X-ray fluorescence technology (pXRF), as large geochemical data sets can be collected rapidly and at low cost. Plutonic Gold Mine (Plutonic), Western Australia, has a growing data set of more than 150 000 pXRF multi-element analyses from core and underground face samples, reconciled to Au fire-assay concentration, and logging codes. This study investigates and statistically validates the consistency with which the logging codes have been applied at Plutonic for the last four years, with respect to both Au distribution and other elements. In doing so, we have developed a schema that allows objective logging to occur once core has been sent for assay and analysed by pXRF. While far from replacing the geologist in the field, this is a complementary method that adds significant value to a data set.CITATION:Gazley, M F, Tutt, C M, Latham, A R, Duclaux, G, Fisher, L A, Taylor, M D, de Beer, S J and Atkinson, K, 2013. Objective geological logging using geochemical multi-element data - Plutonic Gold Mine, Western Australia, in Proceedings World Gold 2013 , pp 455-462 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

The technology of coal preparation, while based on similar processes to those in common useage in the 1950s, has improved significantly over the past 15 years primarily due to advances in process control. This technology at least offers the potential for most coal preparation unit operations to be optimised to a considerable degree. However, to maximise the overall yield of an operation from pit to port, factors often outside of the control of the preparation plant operator have a dominant effect. Specific factors include an in depth knowledge of the feed characteristics of the various sources of coal, the detailed mine scheduling to provide an appropriate blend to the plant, and the interim handling and stockpiling processes between the mine face and the customer.This paper summarises the criteria for optimising the yield for a variety of mining, processing and stockpiling options, based on the principle of operating at constant incremental ash. Pragmatic operating assumptions such as extension of the principle to operating at a constant density for gravity operations will be discussed. A means of optimising the compromise between maintaining specification product ash to the customer and maximising yield by always washing at constant incremental ash, without the benefit of a homogenised feed, will also be Presented.

Jan 1, 1992

By S C. Dominy

The Bendigo Goldfield is located in the state of Victoria, Australia, and is one of a number of quartz-reef fields that make up the greater Central Victorian Goldfield. At Bendigo gold particles are characterised by their very coarse nature, ranging from below 100 to over 10 000 ¦m in size. Some 60 per cent of the gold occurs in particles greater than 1000 ¦m in size. This characteristic ensures that the mineralisation is very challenging to both sample and evaluate. Diamond drilling provides a measure of geological structure, but is a poor measure of in situ grade, understating it by up to 75 per cent. Drilling combined with on-reef development, bulk sampling and geological interpretation has been used to define Indicated Mineral Resources. For grade control, a balance had to be sought between sample representivity, cost, turn around time and practicality. Sampling of extreme nugget effect deposits generally requires the use of bulk sampling in order to be representative. However, the cost and turn around time is significant. As a result, a 50 kg micro-bulk sampling system has been introduced that attempts to overcome these problems by providing a fast, practical method that can discriminate between ore and waste. As the mine passes into production, grade control will increasingly become dependent upon geological data collection and interpretation.

Jan 1, 2005

Production from a major, deep orebody requires the construction of two 6 m diameter, 1000 m deep ventilation shafts over the next three years. Further ventilation upgrades have foreshadowed an additional 1500 m of 6 m diameter shafts beyond that. After reviewing the construction alternatives it was decided to raisebore the first shaft in one pass using Western Mining Corporation's 121R raiseborer and the Wirth sequential head. The significant cost and speed of construction potential of 6 m raiseboring justified the risks associated with this new technology. Large diameter sequential head raiseboring has only been carried out in South Africa. Over the last three years many lessons have been learnt and the technology has progressed to being considered feasible. Operating practice and the optimisation of raiseboring performance for specific ground conditions are the areas requiring further work. The development of large diameter raiseboring in South Africa and the site preparation and initial operation at Z.C. Mines are described. Comment on actual operating experience includes the geotechnical investigations, the raiseborer foundations, cuttings disposal and the drilling of the pilot hole which has progressed to beyond 450 m. Unforeseen difficulties with the verticality of the pilot hole and with mud losses illustrate the types of problems that can be expected.

Jan 1, 1988

By A Cheatle

GoldcorpÆs Musselwhite mine in north-western Ontario, Canada has in recent years become a world-class deposit. Initially discovered in the early 1960s by Alan and Harold Musselwhite, the then marginal mine eventually started production in 1997 and has to date produced 2.6 Moz of gold. Two million ounces of gold are currently classified as Mineral Reserve and a further 1.2 Moz of gold are classified in the Mineral Resource category for a total gold inventory approaching 6 Moz. Growth of the mineral inventory has been achieved through the successful implementation of strategic planning that sought to extend the mine life through discovery of additional economic zones and increased mined tonnages. Accelerated exploration activity commenced in 2001, at a time when gold price was at its lowest in decades. Focus was placed on building, developing and retaining a highly skilled geological team, maintaining purpose, conducting external reviews and developing a new geological model through research partnerships. Ongoing collaborative research between Lakehead University and Musselwhite mine has seen the development of new structural and geological models through post-graduate and academic studies. Research has included lithogeochemical, stable isotope and structural and metamorphic studies and has led to the evolution of a new mineralisation model (for the mine) and the recognition of brittle and ductile deformation regimes within the mineralised horizons. Exploration drilling continues to provide support for the new geologic model. Gold discoveries have extended known mineralisation 2.3 km along strike from mineral reserves and laterally into parallel zones. The exploration potential to further increase production rates, Mineral Reserves and Resources remains very positive and increases in overall gold inventory are likely. Musselwhite mine has significantly exceeded initial projections for a ten year life-of-mine and a marginal existence.

Jan 1, 2009

By P Ritchie, E H. Briese, N A. Currey

Kidston Gold Mines, located in semi-arid North Queensland, Australia is currently in its closure phase. Highly innovative and comprehensive rehabilitation strategies were employed at the site, including the direct revegetation of the surface of the tailings storage; the construction of a tailings sediment entrapment pond; the construction of a spillway to drain large rainfall events from the surface of the tailings; the construction of store/release covers over the tops of the waste rock dumps; the sheeting with oxide waste rock of the waste rock dump slopes; the partial back-filling of the initial Wises Hill Pit with waste rock and thickened tailings produced from the subsequent Eldridge Pit; the partial flooding of Eldridge Pit following the end of mining; and the construction of wetland systems to treat contaminated tailings and waste rock dump seepage. These closure strategies involved the careful consideration of water management. Specific water management issues included understanding the water balance of the tailings dam; the operation of the tailings dam sediment entrapment pond and spillway; understanding the water balance of the store/release waste rock dump covers; the importance and sustainability of vegetation on the tailings, store/release waste rock dump covers, and on the sheeted waste rock dump slopes; the level and quality of water in the partially flooded Eldridge Pit; and the treatment of contaminated seepage in the constructed wetlands. The seasonal and highly variable rainfall experienced in this semi-arid climate posed a number of challenges for the management of water on the site post-closure. The paper details these challenges and highlights how they were resolved over the period leading up to and following the end of mining.

Jan 1, 2003

By He BQ

Static attachment of bubbles to solids is contrasted with dynamic attachment in flotation cells. The times of contact during particle-bubble collisions in dynamic attachment are compared with the induction time determinations and the kinetics of thinning of the liquid films separating solids and bubbles. The thinning is examined mainly in terms of electrostatic and dispersion (van der Waals) contributions to the disjoining pressure existing in the films. The local heterogeneity (on a molecular scale) of charge distribution invariably present at all interfaces (even at conditions of zero zeta potential) calls for some means to minimize possible electrostatic repulsions which arise when the electrical double layer at the air-bubble interface begins to overlap that present at the solid surface, on encounter between particles and bubbles. It is postulated that dipoles of frother molecules, owing to their ability to "flip over" (polarise), replace localized electrostatic repulsion by attraction within fractions of a milli- second, as long as the structure of the frother molecules is sufficiently "bulky" to maintain diffuse films (of mixed collector-frother) at the air/liquid interface of bubbles. The relaxation times of dipoles (signifying their "flipping over" ability) have to be shorter than the collision times between particles and bubbles for particle-bubble attachment to be facilitated under dynamic Conditions.

Jan 1, 1984

All large open pits in Australia have been mined, or are planned to be mined well below the local water table. This raises several issues that impact on mine safety, mining costs and regulatory approvals. Some pits will be æwetÆ, where they are mined through permeable horizons and where there will be measurable groundwater inflows. These will require some form of dewatering. There may also be some difficulties in the disposal of excess water. Other pits, may be ædryÆ, where they are mined through impermeable material and there are no measurable groundwater inflows but where there are stability issues related to hydrostatic pressures within the pit walls. These may require some form of depressurisation. Some pits are a combination of both. Effective management of groundwater inflows and groundwater related stability issues and the development of cost effective and environmentally acceptable dewatering and depressurisation systems requires an understanding of site specific hydrogeological conditions and practical experience in what works best for different conditions. The presentation will include an outline of the key hydrogeological factors that impact on large pits, practical methodologies for achieving dewatering/ depressurisation, and some case studies from the Goldfields, Pilbara and North Queensland.

Jan 1, 2003

Studying the ore textures in a discrete orebody is a novel approach to estimating liberation potential of the ore minerals present. As part of a PhD thesis, this project aims at classifying and quantifying the textures of the Hilton North orebodies, and at estimating their liberation characteristics.

Jan 1, 1993

The future of the United States (US) mining industry will be affected greatly by recent coal mining disasters. These have resulted in new legislation which will have an impact on mining economic costs as well safety and health of miners. This paper discusses the changes that new legislation and regulations are making to the industry and current research that is producing technologies to make mining safer and will likely impact the future of mining.

Jan 1, 2008

By P Cleary, G K. Robinson, J Hilton, P Wilson

Concern has been expressed that Vezins can be biased when used for sampling fine materials if the cutter speed is as high as the 0.6 m/s which is often used. Using modelling techniques that consider airflow as well as particles, we have endeavoured to investigate sampling bias as a function of the size of fine particles, cutter aperture, cutter speed, shape of cutter blades, and the size of the gap between the inlet pipe and the cutter blades. Using crude estimates of the rate of airflow and a simple model of a single particle moving through air led to an approximate rule that bias will not occur due to mechanisms related to airflow for particles larger than about 200 microns; and bias will always occur for particles smaller than about 40 microns. For particles between these size limits, the extent of bias depends on particle density, cutter speed and cutter geometry as well as particle size.CITATION:Robinson, G K, Wilson, P, Hilton, J and Cleary, P, 2012. Avoiding bias when using vezins for sampling dusty materials, in Proceedings Sampling 2012 , pp 109-114 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 21, 2012

Recent and on-going studies on the leaching of gold, the properties and activity of carbon, developments in the elution of gold from carbon, and methods of recovering gold from solution are reviewed. Emphasis is placed on Australian contributions, and their impact on gold metallurgy. Consideration is given to the future development of selective solvent extractants, ion exchange resins or alternative reagents for cyanide.

Jan 1, 1987

Ore sorting is a high capacity, low cost method of preconcentrating ores and in some cases of producing a marketable concentrate. In most cases it is applied to run of mine material, immediately after primary crushing and screening in sizes ranging from 10 mm to 150 mm. Recent developments in bulk sorting of friable uranium deposits have resulted in machines capable of handling fine materials with sensing and separation being achieved on a zone by zone basis. Modern ore sorting machines rely on the synchronous operation of four internal sub systems, feed presentation, sensing, data processing and separation. A variety of different sub systems is available which can be combined in various forms to produce sorters capable of handling a wide variety of mineral types. The benefits in using ore sorting cover a wide range of situations and are applicable to both established mines as well as new mining ventures. Reduced operating costs, increased productivity, capital savings, energy and resource conservation and environmental issues are all part of the reason why ore sorting is finding rapid acceptance in today's mining industry.

Jan 1, 1980

By D S. Perera, P Wal, D C. Southam, J L. Lowe

The Cooperative Research Centre for Sustainable Resource Processing (CSRP) is undertaking a large research project involving partners from industry, universities and government, which aims to develop the necessary chemical and structural understanding of geopolymer materials made from waste products for them to be used to capture a significant market share of the concrete business for a given industrial region. We are investigating the suitability of a range of soluble silica-bearing waste streams for use as geopolymer concrete feedstocks. In order to utilise a variety of waste streams, either singly or blended, an understanding of the role of secondary metal ions (Fe, Ca, Mg, Ti, etc) in the geopolymerisation process is essential. A range of experimental and analytical techniques is therefore being used to better understand the structure-chemistry-property relationships of geopolymers. Currently, we are investigating geopolymers made from a variety of waste streams (fly ash, kaolinite, red mud, etc) available in the Kwinana Industrial Region, Western Australia. This paper will detail how the basic scientific research underpinning the project is vital if waste streams of varying composition are to be successfully used in a commercial concrete product and the regional synergies required to develop geopolymers from waste streams.

Jan 1, 2006

The weathering profile, in arid terrains, is commonly capped by different kinds of hardened crust, whose formation is related to recent or former climates. One may distinguish silcretes, calcretes and the ferruginous (or ferro-aluminous) laterites. the present keynote address mostly deals with the lateritic regolith and, moreover, the influence it has on mineral exploration. The lateritic regolith, also called "cuirasse", is a result of a massive accumulation of Fe (and/or Al) oxides on top of weathering profiles developed during former, probably seasonal humid, climatic episodes, and whose preservation depends on the characteristics of later climates. The total thickness of such weathering profiles commonly exceeds 50 m, with an almost complete substitution of the rock forming minerals by secondary minerals as kaolinite and Fe-Al oxi- hydroxides (hematite, goethite, boehmite, gibbsite). Such an alteration of the primary minerals assemblage is of course accompanied by significant changes of the chemical composition, as concerns major and trace elements. The latter are distributed amongst the main secondary mineral phases or trapped in some primary resistant minerals, but may also be leached, totally or partially. Gold is also affected by lateritic weathering, as shown for instance by morphoscopic and geochemical studies of gold grains collected in the different horizons of the profile, which indicates some dissolution followed by reprecipitation.

Jan 1, 1988