Search Documents

By T A. Short, P L. Brown

Kestrel Mine co-disposes around 1.5 Mt of fine (2SO4/t and to date around 9 Mt has been deposited. The mine plans to co-dispose of approximately 39 Mt of material, creating a dump with a maximum height of 35 m and a disturbance footprint of 260 ha. Benign materials suitable for rehabilitation are severely limited and no successful rehabilitation strategy has yet been demonstrated. A rigorous measurement and modelling program is resolving outstanding issues associated with acid rock drainage (ARD). The objective of the program is to develop and validate a strategy for dump rehabilitation that will control ARD and allow for mine closure. The strategy includes using a soil cover to reduce water flux into the dump to control the overall oxidation rate and to control effluent release. Monitoring of the oxygen distribution and water flux in the uncovered material commenced in February 2001 and monitoring in waste under a trial cover commenced in February 2002. Carbonaceous and sulfidic oxidation rates have been measured. Initial modelling indicates that the carbonaceous material has the general effect of slowing the rate of pyrite oxidation, lowering the maximum sulfate production rate and extending the time to oxidise all the sulfides. The combined approach of measurement and modelling provides a sound basis for assessing the performance of the trial cover and predicting the long-term quality and quantity of effluent at the base of the rehabilitated waste dump.

Jan 1, 2003

To follow the development of the central crushing plant it is necessary briefly to outline the history of the Lake View and Star Limited. This Company, when first constituted, took over the properties of the Lake View Consols, Hannan's Star, and Chaffers Gold Mines.The Company then treated the ore won from these leases at two dry crushing, all-roasting plants, situated adjacent to each other on the site of the present Chaffers Treatment Plant that handles all the ore won by the Lake View and Star Ltd.SUbsequent to the initial union of the three companies mentioned, the Ivanhoe Gold Corporation and the Golden Horse Shoe Ltd. were absorbed. Still later, and after the original crushing plant was erected, the Associated Gold Mines of Australia were purchased.A very extensive development policy was adopted by the Company's management in the late 1920's, and as the underground programme progressed, it became eVident that a large treatment plant would be required. Wet milling of the ore, followed by flotation, was considered desirable, and the necessity of a central crushing plant capable of producing a feed that could be handled by the wet ball mills attached to it was obvious.At this time, each of the properties absorbed had its own crushing station, situated adjacent to the respective...

Jan 1, 1948

By Palmer DJ

Mercury is introduced into EZ's electroly tic zinc/sulphuric acid plant complex at Risdon, Tasmania, in zinc sulphide concentrate. Mercury is volatilised during the roasting operation and then distributed in the sulphuric acid plant effluents and product acid. Following an investigation of the factors determining the mercury distribution, a plan was formulated to-provide an environmentally accep- table degree of mercury containment at Risdon. This paper discusses details of the various control measures investigated and out- lines the reasons for selecting the particular procedures finally adopted for the Risdon plant.

Jan 1, 1980

By Reilly L, Worner H. K

The EnvIRONment process has been developed to treat steel works dust and organic wastes simultaneously. A pelletised feed is fed into a special DC electric furnace, the pellets becoming immersed in a molten slag above a carbon saturated bath. The iron oxide in the pellets is reduced and carburised whilst the organics are broken down to carbon monoxide, carbon dioxide, hydrogen and water vapour. Volatile metals are vapourised and collected in the baghouse. Over two years of trials in a 100 kg DC electric are furnace has brought the process to the stage where it is ready for commercialisation.

Jan 1, 1995

Intrusion related Cu/Au mineralisation is localised in Pacific Rim island arcs by arc parallel, termed accretionary structures; or arc normal, termed transfer structures. In Papua New Guinea, NE trending transfer structures, evident on Landsat imagery, represent deep crustal fractures which have facilitated dextral rotation of the mainland during oblique plate collision. Major structures localise intrusion centres, and by rotation, develop ore hosting dilational environ-ments in subsidiary structures. While transfer structures localise the Porgera, Wafi and Yandera porphyry centres, the Frieda Porphyry and associated Nena high sulphidation Cu/Au mineralisation are localised by accretionary structures. The Bulolo Graben, which hosts the Morobe Goldfield, developed during intra arc rifting aided by movement on transfer structures. Crustal thinning has initiated magmatism with which diatreme breccias and fracture controlled mineralisation are associated.

Jan 1, 1994

By Matsuo T, Uga Y

The tunnelling work to construct a sewage trunk line designed by the Sewage Bureau of Kobe City along north side slope of Rokko mountain range incorporated an all ground condition type (broad spectrum) TBM with slurry transport system with jet pump manufactured by Kawasaki Heavy Industries, Ltd. Boring dia. of the tunnel measured to 2.0 m. The construction planning and implemen- tation were done by Ohbayashi Corporation, the general contractor. The heading way was 3342.4 m in overall length.; construction work ran from April '84 to June '85. The max. daily progress marked 31.9 m and the max. monthly progress 493.1 m according to the relevant record. The machine proceeded with the work under geological conditions featured with conglomerate, rhyolite, tuff breccia and slate, whereby soft soil zone mostly of clay was encountered in a limited area. In the latter case, however, steel segments were substituted for supporting steel ribs. The tunnel was routed beneath a meandering road with the result that more than 40% of overall length show a curvature of 50 to 200 m radius.

Jan 1, 1987

The western Cordillera of North America, including more than 99% of Alaska, is made up of an agglomeration of litho-tectonic terranes, some of which have undergone large rotations and (or) translations. The larger terranes can be broadly grouped into a small number of composite terranes based on affinities in their lithology, structure, and tectonic evolution. The terranes reflect repeated episodes of marginal rifting as well as formation of marginal arcs, island arc chains, back-arc basins, and oceanic plateaus since late Proterozoic time. Accretion to the continental margin occurred mainly from Middle Triassic through Early Cretaceous time. Major northward dispersal of terranes was largely during the existence of the Kula plate from about 85-55 Ma. Major rotations are the mid-Cretaceous opening of the Arctic Ocean basin with counterclockwise rotation of Arctic Alaska and Laramide oroclinal bending of western Alaska. The present complex Cordilleran geology along the northeast Pacific rim is a sum of these earlier accretionary processes together with continued Cenozoic faulting and deformation that has been superimposed upon the agglomerated displaced terranes over a broad segment of the continental margin.

Jan 1, 1990

By B Mennie, R Poedjono, G Coad

PT Freeport Indonesia operates a large copper and gold mining operation near Tembagapura, Papua (formerly, Irian Jaya), Indonesia. This is a remote location with its own set of unique operational characteristics. The mining and concentrating operations typically produce a concentrate containing 2500 tpd of copper and 6000 oz of gold per day from the combined mining of a 45 000 tpd (ore) block cave operation (DOZ Mine) and a 190 000 tpd (ore) open pit mining operation (Grasberg Open Pit). The Grasberg Open Pit mine will be exhausted in 2015 at which time FreeportÆs operations will entirely underground mining methods. The Common Infrastructure Project (CIP) incorporates the elements required for the shift to underground mining at a production rate approaching 200 000 tpd. The AB Adit portion of the CIP will provide deep level access to the Grasberg Block Cave (below the Open Pit), Kucing Liar, Big Gossan, and the Mill Level Zone orebodies. Commencement of the project was September 2003. The Grasberg Block Cave is planned to start production in 2014. This paper provides details on the project scope, innovative contractual framework, advancement of mining methods throughout the life of the operation, equipment selection, manpower selection, training, geological, and socio-political conditions related to the project.

Jan 1, 2005

By P Stoker

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Mining and exploration properties have a unique set of technical risks. Privately-owned companies considering investing in the resources sector can optimise their investment decisions by adopting a systematic technical assessment of acquisition assets, similar to the approach commonly adopted by public financial institutions and publicly-listed companies.Technical due diligence provides a process to identify key geological, mining, geotechnical, metallurgical, environmental and social risks and opportunities and determine the most likely business case and valuation of assets. Technical due diligence is commonly carried out in parallel with legal, commercial and financial due diligence, often involving the acquirer, to maximise the understanding of the investment.There are significant advantages in investors conducting a comprehensive technical due diligence, which typically involves site visits and project assessment to international standards by an independent, multidisciplinary team of experts. The outcomes provide the opportunity for the investor to make early, informed decisions and to understand and manage risks.Technical due diligence may be carried out at several stages: when considering and weighing up a number of investment options, prior to and during a transaction or immediately post-transaction. In the first stage, the outcomes will inform the choice of investment and, more particularly, whether there are any fundamental flaws in the projects being considered. In the second stage, due diligence outcomes can inform the level of investment and approach to risk management and planning. In the third stage, risks and opportunities can be investigated in more detail, allowing the investor to consider the best options to reduce risk and maximise the benefit of the investment.This paper presents a summary of the technical due diligence assessment process, its benefits to investors, common risks in mining and exploration projects known to cause mining asset write-downs and principal technical due diligence approaches.CITATION:Keogh, A, Stoker, P and Thomas, M, 2015. Benefits of due diligence in private equity mining investments – maximising value and unearthing common risks , in Proceedings PACRIM 2015 Congress, pp 115–126 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

Crandallite and millisite in Christmas Island 'B' and 'C' phosphate ores are rapidly decomposed by sodium hydroxide solutions at about 80QC. As these phosphates generally contain less than 1% silica, an alkaline extraction process can be designed, in which up to 95% of the sodium hydroxide used, may be recycled. The insoluble residue consists of an impure, highly reactive apatite, which in pot trials, has given good responses as a direct application fertiliser; alternatively this residue can be underacidulated to give a granular product with fertiliser potential. The hot leaching solution contains up to 95% of the alumina and approx- imately half of the phosphate from the original ore. Simple crystallising techniques have been developed on a laboratory-scale to use this leaching solution for producing smelter-grade alumina and detergent-quality trisodium phosphate. As the demand for detergents is limited, an investigation was made of the reaction between trisodium phosphate and slaked lime, derived from a high-grade New Zealand limestone occurring near Oamaru. The product is calcium phosphate, containing up to 40% P205, and less than 0.2% each of iron, aluminium and fluorine, and it should be a useful raw material for phosphoric acid manufacture. A preliminary economic evaluation of the whole process looks promising, And warrants further investigations, including pilot-plant work.

Jan 1, 1971

By Winrove G. S, Herdie G. J, McCarthy C. A

Production of hot metal from the Hlsmelt Research and Development Facility at Kwinana, Western Australia commenced in October 1993. The stand-alone facility is a unique, coal-based, integrated ironworks equipped to process iron ore fines to pig iron and simultaneously undertake a wide range of research tasks. The data generated will be used to verify the commercial potential of the technology and to set the design and operating parameters for a full-scale production plant. The design, construction, commissioning and initial operation of the HRDF has required many innovative and practical solutions to be developed and implemented by the international group of organisations contributing to the Hlsmelt Project. Initial operation has produced results which demonstrate the potential of the unique process technology associated with the core plant smelting unit. The recent achievement of post-combustion levels of 60 per cent with heat transfer efficiencies greater than 85 per cent demonstrates that the performance obtained with the Small Scale Pilot Plant in Maxhutte, Germany can be reproduced at a larger scale. The results presented in this paper support the thrust for further intensification and future commercialisation of the process.

Jan 1, 1995

By M D. Sussman

A large number of countries in the world now have some regulation for labelling the presence of genetically modified organisms (GMO) in food. For the last ten years, ISO/TC 34/SC 16 has been providing methods, guidelines and requirements concerning the evaluation of molecular biomarkers including GMOs. This activity makes sure that stakeholders on all sides of commercial transactions are satisfied and their marketing or regulatory needs are met. Developing and maintaining a transparent, science-based environment for users of horizontal methods for molecular biomarker analysis is a high priority. Sampling and analysis of molecular biomarkers has become critically important for food and agricultural organisations developing, producing, distributing and selling genetically engineered, non-genetically engineered, identity preserved and/or organic crops and their derived products and preventing their respective destructive diseases. To aid in international harmonisation, a new work item proposal to develop an ISO type A management system standard (MSS) for organisations including laboratories using molecular biomarker analysis and sampling has been submitted to ISO/TC 34/SC 16. The purpose of this MSS is ensuring that determination of the presence, absence or quantification of a particular biomarker with a relationship to a product quality determinant, a marketing claim, a regulation or a plant pathogen is carried out under a suitable quality assurance / quality control system. This MSS will provide an overarching system to apply and manage molecular biomarker analysis and sampling for any organisation large, medium or small in a private, government or academic setting.CITATION:Sussman, M D, 2017. ISO/TC 34/SC 16 horizontal methods for molecular biomarker analysis – molecular biomarker analysis and sampling management system, in Proceedings Eighth World Conference on Sampling and Blending , pp 295–302 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

Economic and technical reasons forced the mining industry all over the world to increase the unit size of mineral processing equipment. in large flotation cells, this development leads to problems in areas of air dispersion and keeping solids in suspension. Outokumpu, an operating mining company, designed and developed a mixing mechanism for large flotation cells at its own concentrators and also studied problems related to tank design. Ideal conditions for flotation can only be achieved if the flow pattern created by the mixing mechanism fits well into the tank configuration and the risk of short circuiting is minimized. In large deep flotation cells, four different zones can be found which improve the behaviour of large cells when compared to small cells. Selectivity is increased and in some cases final concentrate grades can be produced from the rougher cell. The largest units have also been used as final cleaners in some installations. When modernizing old plants by installing fewer larger flotation cells, immediate and substantial savings in power consumption are achieved. Additional power savings are made in pumping costs because of simpler circuit design and decreased circulating loads

Jan 1, 1978

By S Tyrrell, B Jackson, K Matson

Northern Star Resources Limited Jundee Gold Mine in Western Australia operates a comminution circuit that consists of a primary crusher, 3.85 MW semi-autogenous grinding (SAG) mill, 1.8 MW ball mill and pebble recycle crusher. In 2017, a secondary crushing circuit was installed to remove the SAG mill throughput bottleneck and increase production of highly competent underground ore from 1.35 to a minimum of 1.7 Mt/a.This paper discusses the findings from the trial phase, the circuit design, project delivery, site optimisation, and the plant performance.CITATION:Matson, K, Tyrrell, S and Jackson, B, 2018. The application of secondary crushing at the Jundee gold mine, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 485–496 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By Short KC

The Hunter Region, with a major part of the coal resources of New South Wales and a long history of coal mining, has experienced a rapid expansion of coal resource development in recent years. While there are inevitable conflicts between mining, urban development and related infrastructure, and between mining and other resources, the application of sound planning practices, and improved co-operation and co-ordination among the various parties, helps to reduce such conflicts. The planning process involves consideration of factors such as transport- ation (including port facilities), mine subsidence, provision for surface facilities, a,iC the need for buffer 'ones. In addition, provision must be made for urban expansion, often co-existing or in close proximity to present or future coal mining development. Approval of coal mining developments takes place within the legislative framework of the Environmental Planning and Assessment Act, 1979 (EPA Act), the Coal Mining Act, 1973 (CM Act) and the Mining Act, 1973. Considerable effort has gone into stream- lining and co-ordinating the procedures under these Acts. The EPA Act provides for regional and local environmental plans, as well as a linked process of development control and environmental impact assessment. The CM Act provides for the grant of exploration and coal mining titles and mechanisms for the responsible management of Mining.

Jan 1, 1987

By T Baumgartl, R Akesseh, M Edraki, B Usher, M Shaygan

With the continuing demand for industrialisation and urbanisation, the rate of mining and processing lower grade ores will also increase, producing large quantities of waste. As extreme weather events associated with global climatic changes are to be expected, the risk from mine tailings management will also increase (Edraki et al., 2014). In sulfide rich tailings, weathering within the critical zone controls the fate and distribution of the contaminants such as copper, zinc, and lead in the environment (Hayes et al., 2014). Tailings evolve geochemically and physically with time as they age under the influence of complex interacting factors. Understanding of the complex interactions between these controlling factors is important for predicting and mitigating the potential risks associated with sulfide tailings such as generation of acid mine drainage (Lindsay et al., 2015). Wetting and drying initiates weathering processes, influencing the hydrological, geochemical and geomechanical properties of the tailings. In semi-arid climates where evaporation exceeds precipitation, salts may precipitate within the pore system as well as on the tailings surface. These salts become the temporal sink of heavy metals until the next episodic rainfall (Nordstrom, 2011, Grover et al., 2016). Therefore, using kinetic and static test to describe the trajectory of these material evolutions without considering the complex interactions could potentially lead to erroneous prediction. In order to understand these relations, the effect of drying and wetting cycles on the hydrological, geochemical and geomechanical properties of ageing tailings was studied to draw conclusions for advanced tailings site rehabilitation and mine closureCITATION:Akesseh, R, Shaygan, M, Usher, B, Edraki, M and Baumgartl, T, 2018. Wetting and drying cycles as a means to determine the effect and consequences of tailings ageing, in Proceedings Life-of-Mine 2018, pp 24–27 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By Montini A

The dynamic behaviour of the load in a pilot-scale ball mill has been measured as a function of axial position within the mill, end plate lifter design, load volume J (percent of mill volume), percent solids in the slurry S and mill speed N (percent of critical speed). Conductivity probes were inserted through the shell of the mill to provide online measurements of the dynamic orientation of the load in the mill. It was found that 1. the height of the shoulder of the load is increased by increasing J, S or N. 2. Measurements of the effect of S on the location of the shoulder of the load should be very useful in mill control strategies. 3. The axial centre of gravity of the load in the mill is not affected by operating conditions. 4. The presence of lifters on the feed end plate does not affect the torque drawn by the mill. 5. Holdup of slurry in the mill is a strong function of slurry viscosity and a weak function of mill speed.

Jan 1, 1986

The Dizon open pit mine of Benguet Corporation in western Central Luzon, Philippines has yielded some 182 000 t copper, and about 26 000 kg gold and 48 000 kg silver as by products since it started operation in November 1979. The 140 million tonne orebody is associated with a small quartz diorite porphyry stock emplaced in volcanic rocks on the basal slope of a stratovolcano complex as stockworks, fracture fillings and disseminated sulphide mineralization averaging 0.43% Cu, 0.93 g/t Au and 2.5 g/t Ag. Intense hydrothermal alteration accompanied the mineralization that developed fairly distinct mineral assemblages within and around the intrusive. Post-ore volcanic activity later gave birth to an upward-flaring diatreme which broke out south of and adjacent to the orebody and partially destroying it. Subsequent volcanic activity buried the mineralized area along with the rest of the stratovolcano's surrounding slopes under a thick deposit of pyroclastic and laharic debris. Erosion eventually removed the volcanic cappings over Dizon and also exposed the quartz diorite porphyry stock which might have resulted in the truncation of a sizeable section of the Dizon deposit. The chain of stratovolcanoes that comprise southeastern Zambales range hugging the southeastern edge of the Zambales ophiolite is part of a west-facing volcanic arc that extends for some 300 km along the western margin of central and southern Luzon whose development has been correlated to the subduction in the Manila Trench located off the west coast of Luzon. Prominent WNW-trending lineaments that cut across the ophiolite appear to be splays of the Philippine Fault whose intersection with the Mt. Pinatubo stratovolcano complex might have localized the emplacement of a number of intermediate stocks along with the gold-rich porphyry copper mineralizations associated with some of them.

Jan 1, 1987

The Taupo Volcanic Zone in New Zealand and the Philippine Mobile Belt in the Philippines are characterized by active subduction, active volcanism and high seismicity. The main factors affecting characteristics of geothermal systems in both countries are: tectonic setting, source magmas, maturity of the systems, and depth to the degassing magma body. Within New Zealand, geothermal systems are grouped into arc- and rift-type. Fluids in arc-type systems contain high amounts of volatiles (40%) and higher Cl contents (3,000-10,000 mg/kg). Maximum temperatures are also higher, reaching up to >400¦C. Arc-type alteration assemblages in New Zealand and the Philippines are similar. Because Philippine geothermal systems are less mature, have higher temperatures and steeper geochemical gradients than New Zealand ones, advanced argillization is more widespread occurring down to depths of 2000 m. Mineral phases are more varied due to the active input of magmatic waters and the formation of vapor conditions at depth, forming P04-, B-, Li-, Ce-, F-, and Cl-bearing minerals at high temperatures. In the Philippines, high temperature magmatic-hydrothermal to contact metamorphic assemblages containing biotite, amphiboles and pyroxenes are relatively common, but rare in New Zealand.

Jan 1, 1995

By D Gagnon, P Bouchard, F Vanier, E Soares de Lima Filho, J El-Haddad, M Sabsabi, G J. Wilkie, A Beauchesne, A Hamel, A Blouin, T Vaillancourt, F Boismenu, A Harhira, A Plugatyr, C Padioleau

Quantitative mineralogy is an established discipline in the geosciences and is aimed at providing mineral grade and texture information for geological and mineral processing applications. The two core technologies underpinning Quantitative Mineralogical Analysis (QMA) are Scanning Electron Microscopy (SEM) in combination with Energy-dispersive X-ray Spectroscopy (EDS). Technologies such as QEMSCAN and MLA are now routinely used to optimise the performance of large-scale mineral processing plants in the base and precious metal sectors. One of the major disadvantages of the QMA methods used today is extensive sample preparation requirements which make application of this technique to real-time mineralogical characterization not feasible. A breakthrough has been achieved by the National Research Council Canada in collaboration with CRC ORE by developing a novel Laser Induced Breakdown Spectroscopy (LIBS) based technology capable of real-time mineralogical characterization of process streams without sample preparation. The potential applications of this technology include, but not limited to, in-pit muck piles, underground draw points, cross-belt analysis as well as slurries. This paper describes the development of the LIBS-based technology from a proof-of-concept (TRL2) to the construction of a prototype sensor and its validation in a simulated environment (TRL5). Future work is being planned to test and further validate the LIBS sensor on a mine-site which will progress the technology to its next readiness level (TRL6).

Nov 10, 2020