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By Jingcai Xu, Singming Gou

A sound mathematical model is an important step to predict spontaneous combustion probability so that measures against coal self-heating can be adopted in time and at comparatively low-cost. This paper analyses main factors in coal spontaneous

Jan 1, 1998

By M Fisher, P Bradley, D Rogers

New England Antimony Mines has operated the Hillgrove Gold Plant at Hillgrove in New South Wales since 1969, producing stibnite and arsenopyrite products by selective flotation. Gold is present in the ore as fine free gold, gold associated with stibnite and gold associated with arsenopyrite, with some ten to 20 per cent of the gold reporting to the antimony stream and 35 - 50 per cent reporting to the arsenopyrite stream. Opportunity to process the arsenopyrite concentrate for onsite recovery of the gold values to improve upon the ten per cent recovery achieved by conventional cyanidation was recognised and subject to comparison with biological oxidation, roasting, nitric acid oxidation, low temperature oxidation (Activox«) and conventional pressure oxidation. Following further testwork and a feasibility study, a 7500 tonnes per annum concentrate feed pressure oxidation autoclave circuit was constructed at Hillgrove and commissioned in October 1999. The plant has operated at the close to design capacity since commissioning whilst optimising various operational and metallurgical aspects. The last three years has seen the process achieve an overall gold recovery of greater than 90 per cent for oxidised concentrates.

Jan 1, 2002

By R L. Grogan

Mining is currently undergoing a progressive expansion into novel environments (such as the deep ocean), commodities (such as tantalum, rare earths, and other ‘green economy minerals’), and new methods (such as the autonomous underwater cutting machines required to operate in the deep ocean environment, or the use of expanding grouts to deliver a blast-free mining method). The advent of novel mining, environments and commodities heralds an era that will undoubtedly start with much discomfort on the part of regulators and stakeholders, due to a feeling of overwhelming uncertainty. These proposed mining scenarios have few precedents, few examples of successful implementation, short baseline monitoring periods, and few examples of legacy sites that may assist with understanding long term risk and exposure. The evolution of the environmental and social impact assessment (ESIA) process in many regulatory environments recognises stakeholder engagement in a formal and facilitated manner. This is a positive step, and allows stakeholders to be much more meaningfully involved in the permitting process than they historically were. However, with this advance comes the challenge of identifying and communicating with stakeholders; sharing information in a meaningful way, fostering relationships with what can be an extremely large group, and delivering on commitments that inspire confidence to permit operations that have never been permitted before. In order to meet this challenge, it is suggested that changes to collection of data, communication of data, the nature of commitments, and the reporting of performance need to be made in order to effectively communicate management of new technologies, and the impacts that mining may have in new environments (such as the deep ocean). The communication challenge is necessarily greater when describing technology that has never been used, or environments that have never previously been accessed by humans on an industrial scale. CITATION:Grogan, R L, 2018. Permitting in the face of uncertainty – how to deliver confidence to regulators and investors, in Proceedings Life-of-Mine 2018, pp 46–48 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By R Lastra, Y Choi, C Hamilton, P Kondos

Hydroseparation (http://www.cnt-mc.com) was used to concentrate sized fractions (from <38 ¦m to 150 ¦m) of various ore products ahead of carbon-in-pulp (CIP)-treatment. The resulting size-by-size concentrates were mounted as monolayer polished sections and subjected to automated unattended precious metal searches by image analysis (see Lastra, Wilson and Cabri, 1999). Systematic variations in Au-deportment permit quantification of Au reporting as discrete grains from fresh-feed through to pressure oxidation (POX)- and CIP-feed. Application of hydroseparation, image analysis and assays to characterising tailings (from <10 ¦m to 106 ¦m) from four mine sites is also described. Results are encouraging enough to predict that the combination of hydroseparation (HS) and automated image analysis could become a standard methodology for study of precious metal ores and metallurgical products.

Jan 1, 2008

By D J. Cronin

Alcoa World Alumina AustraliaÆs Huntly and Willowdale bauxite mines are located in the Darling Range of South Western Australia, which places their operations within PerthÆs surface water supply catchments. These catchments supply Perth with its highest quality drinking water. With the decreasing rainfall trend of recent years catchment yields to water supply reservoirs have reduced to such an extent that water use restrictions were necessary in Perth for 2001, 2002 and 2003. Protection of catchment water quality and water use conservation are crucial issues for AlcoaÆs operations within the Darling Range. Alcoa has been conducting bauxite mining activities in water supply catchments since the mid-1960s. During that time Alcoa has worked closely with the relevant State Government water and environmental agencies to ensure that its operations do not adversely impact catchment water yield and water quality. Monitoring and research have shown that Alcoa has the necessary environmental management systems in place to ensure it can continue to operate in a sustainable manner within water supply catchments. AlcoaÆs mines reduced the volume of water taken from public water supply catchments by 24 per cent in 2002, compared with 2000. This success has had an added benefit; Alcoa does not need to develop a new water source for its Huntly Mine. The conservation measures implemented to reduce water use include: increasing water recycling, using chemical additives for haul road dust suppression, conducting water audits, reducing water demand, monitoring water use, promoting water use targets and training staff in water conservation.

Jan 1, 2003

The design, construction and operation of a 500,000 tonne per year Carbon-In-Pulp (C.I.P.) plant at Kambalda embracing the period from 1980 to 1982 has been previously discussed (Sceresini, 1982).Since that time the annual throughput rate has increased to 780,000 tpy.This paper discusses the changes and improve-ment made to allow this increased production to occur with minimal capital expenditure.

Jan 1, 1984

By E Ruhanen, S Kauvosaari, M Kosonen, C Meintjes

The Yara Siilinjärvi plant is located in the central part of Finland. Siilinjärvi is Western Europe's only apatite mine and annually it produces 1 Mt of apatite concentrate, which creates approximately 10 Mt of tailings.At the beginning of 2017, tailings handling in Yara Siilinjärvi was brought to a new era, by replacing the conventional tailings storage facility with a new tailings treatment plant. The new high-density tailings disposal system with two paste thickeners increased the percentage of solids in the slurry from 45–48 per cent to 66-68 per cent, making it possible to deposit as a paste. This extended the life-span of the current tailings storage facility by 15 years; from 2020 to 2035.This paper presents the storyline of the Yara Paste Plant Project. The project began with laboratory testing and then progressed to pilot-scale thickening and beaching trials. After some successful pilot trials, the final process design was implemented. Process instrumentation and automation played a key role in the project, as the aim of the Yara Project was to make the plant operable remotely from the main plant. An advanced control system is needed to maintain process stability and the desired operation point in various operational circumstances.This paper discusses the results from the Yara site since the new tailings treatment plant commenced. Some of the main points are that the operation has been running consistently with an underflow solids content of 66-68 per cent, with average beach slope angles of 3.5 degrees in the tailings disposal area. This control system additionally facilitates minimum use of flocculant, which delivers significant savings to operating costs. Robust thickener operation also leads to the trouble-free high-density pumping and high availability of the Paste Plant. During the first year of operation, the plant’s availability has been very good, over 97 per cent.Currently, the plant still has its own staff working there during the daytime, but the Paste Plant is now already operated remotely during the night shifts. The long-term goal is to gradually transition into operating the plant completely remotely.CITATION:Ruhanen, E, Kosonen, M, Kauvosaari, S and Meintjes, C, 2018. Optimising the operation of paste thickening at the Yara Siilinjärvi Plant, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 297–310 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By A M. Hagni

Certain copper ores from the Nchanga Copper Mine in the northern Zambia Copperbelt are refractory with respect to conventional beneficiation techniques. This paper reviews recent study of those ores to determine their mineralogy, textures and nature of copper occurrence. Two suites of refractory ores were selected for study: 1.  samples of stockpiled ores from an open pit, and 2.  drill core samples from copper ores. Both sample suites are from the upper orebody at Nchanga and contain about 0.3 - 1.4 per cent copper as determined by atomic absorption, but they represent separate stratigraphic, mineralogical and beneficiation problems. Ore microscopic examination showed that fine-grained copper sulfides are totally lacking from both suites of refractory ores. Petrographic study found malachite in the refractory ores from the open pit, but that malachite probably is post-mine. The opaque mineralogy of the open pit refractory ores is dominated by goethite that occurs mostly as pseudomorphic grains after pyritohedral pyrite crystals that average 200 - 250 ¦m across. Haematite occurs as bands within or as outer shells of the goethite grains. Additional goethite occurs locally as finer-grained areas of exotic goethite. The opaque minerals in the drill core refractory ores are dominated by euhedral ilmenite crystals about 50 - 175 ¦m long. Anatase is the dominant opaque mineral in some drill core samples where it is largely pseudomorphic after ilmenite crystals. Goethite accompanies malachite in unusual drill core refractory ores that have experienced intense hydrothermal alteration. Thus, ore microscopy and petrography showed that fine-grained chalcopyrite and bornite and pre-mine malachite were not the causes of the refractory nature of the ores studied. Electron microprobe revealed that most of the copper occurred in solid solution within micas. Application of automated SEM techniques has provided a detailed understanding of the distribution of copper in these refractory ores.

Jan 1, 2008

A model has been developed for the per iodical maintenance of bins used for hydraulic hoisting in mining of steeply inclining coal seams. This model gives a control plan for hoisting, bin switching and bin maintenance on a regular schedule.

Jan 1, 1977

By P Grouhel

In the recent years several new blasting technologies have come into use in surface mines. Electronic initiation, low-density emulsion explosives and modelling software are in regular use throughout the world. In Australia, these new technologies have achieved significant application, largely in open cut coal mines where more than 20 per cent of blasting is now conducted with electronic initiation systems. These new techniques have contributed to the vast improvement in blasting outcomes evidenced by increased recovery of saleable product and faster excavation rates. In large surface mines, OricaÆs unique combination of electronic initiation systems, bulk emulsion explosives and modelling software can be harnessed to target critical value outcomes. This includes targeting better fragmentation, increased ore uncovery rates and better wall stability û all adding to improved mining operation profitability. Orica Mining Services have combined these technologies into a set of offerings called Blast Based Services (BBSÖ). The paper describes applications of these new technologies and possible benefits in large surface mines.

Jan 1, 2007

By ZáWang, F Hungerford, T Ren

Operations in an underground drill site have to co-exist within the mineÆs ventilation and operational system. The space requirements of a drilling operation have to be adapted to the limitations provided in available site space, which is usually defined by standard mining operations and geotechnical influences. These limitations affect borehole design, equipment positioning in the site layout and possible interactions with mining equipment and services such as water and power supply.The ventilation requirements for drill sites and the means employed vary with depth of the site, space and likely presence of gas. All drilling operations provide a particular service for the mine and in each case, drilling must operate in a manner which controls all gas, water and cuttings returning from the borehole. The various standpiping systems employed have evolved under differing influences and must cater for conditions during and after the drilling operations.The influences that gas content, pressure and flow, rib stability, cleat direction, borehole length, potential water pressure and flow have on a mineÆs operation and ventilation systems have to be considered in the design of standpipe length, diameter and fittings. Past history has a strong influence on common practice while worst case effects of a possible in-hole event should be catered for.This paper describes the early drilling systems and their limitations in ventilation and gas management. The drill site dimensions and set-up are discussed in the context of roadway conditions, equipment layout, ventilation and logistics. The use of standpiping to control all returns from the borehole is illustrated by referring to likely scenarios in a drilling site to achieve the most effective sealed depth to accommodate the worst case possibility of intersecting high pressure gas or water during the drilling operation. Practices to allow gas drainage in the return airway of a panel are described.CITATION:Hungerford, F, Ren, T and Wang, Z, 2013. operational management of underground in-seam drilling sites, in Proceedings The Australian Mine Ventilation Conference , pp 43-48 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By K Esmaeili, S Aziznejad

Impact-induced rock fragmentation is a mechanism that is commonly used for rock breakage in drilling and crushing. Additionally, rock fragmentation by blasting is frequently used in rock excavation operations. Experience shows that the presence of discontinuities can significantly influence the impact-induced damage and fragmentation of rock. Quantification of the response of jointed rock masses to impact loads is complicated by the fact that the available laboratory tests are mainly designed for aggregates or intact rocks. It can be argued that neither of these tests adequately represent a jointed rock mass. This paper presents the results of a series of numerical simulations used to investigate the influence of pre-existing discontinuities on the impact-induced fragmentation of rock masses. The methodology includes determination of the static and dynamic mechanical properties of a rock unit by conducting a series of laboratory tests on intact rock samples collected from a quarry in Canada. A 2D distinct element code, Particle Flow Code, was used to generate a bonded particle model in order to simulate both static mechanical properties (uniaxial compressive strength, elastic modulus, Poisson’s ratio and indirect tensile strength) and dynamic mechanical property (drop weight tensile strength) of the intact rock. The calibrated numerical model was then used to construct large-scale synthetic rock mass samples by incorporating discontinuity networks of different intensity into the bonded particle model. Finally, the impact-induced fragmentation inflicted by a rigid projectile particle on the jointed rock mass samples, simulated by a synthetic rock mass model, was determined. More fragmentation was observed for the rock mass samples with higher joint intensity.CITATION:Aziznejad, S and Esmaeili, K, 2015. Effects of joint intensity on rock fragmentation by impact, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 377–384 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By P Sutton

The global goal of Sustainable Development is not achievable without major changes in the way goods and services are delivered and material needs are satisfied, which requires tremendous innovation in the supply chains and life cycles in which minerals and energy processing take part. Values derived from minerals and metals processing need to be delivered with a fraction of current ecological impacts, which means removing technical obstacles to eliminating waste and emissions in the minerals cycle. The challenge is to find economically attractive ways to get there, through eco-efficiency gains in existing operations, capturing regional synergies, streamlining and greening the materials supply chain, and commercialising new process technology and new products. This paper summarises the outcomes of the Sustainable Resource Processing project, which was designed to provide a strategic analysis of what sustainability means for minerals and metals processing and how that can be effectively translated into technical and business innovation.

Jan 1, 2002

Study on Reasonable Mineral Processing Flow Sheet of Yunfu Low-Grade Pyrite Ores Low-grade ores in Yunfu Pyrite Mining Area were investigated, in order to find an economical, reasonable and environment-friendly mineral processing technology, which is of low consumption and high efficiency in pyrite recovering, which can ensure that the quality of pyrite concentrate product is eligible for sale and the sulfur content of the discharged tailings meets the national emission standards. A flow sheet with a classification, a jigging for coarse-grain minerals and a spiral chute separation for fine-grained minerals was adopted, and the sulfur grade and recovery of the pyrite concentrate is 35.50 per cent and 86.70 per cent respectively, while the grade of tailings is only 6.70 per cent.

Sep 13, 2010

By J, J M. Young, P T. Nielsen, R Zhu

Improved understanding of the variables that influence hydrocyclone performance is of increasing interest to the iron ore industry, where hydorcyclones are widely used to deslime fine ore. In many cases, the impact of particular variables is not quantified sufficiently well experimentally to ensure that industrial performance will match expectations. The current work focused on developing and implementing a systematic methodology to evaluate and compare the performance of four different hydrocyclones in a desliming application. A critical component of the project was the design and construction of a pilot-scale hydrocyclone rig using state of the art monitoring and sampling methods. A wide ranging test programme was conducted to quantify the effect on metallurgical performance of the key hydrocyclone variables such as pressure, feed density, vortex finder size, spigot size and hydrocyclone make/overall design. Details of the experimental approach are presented, along with a discussion of the sizing analysis methods used. Performance criteria were established to assess the four hydrocyclones. The effects of each major variable were quantified over a wide range of conditions. The results show that clear performance differentiation was achieved, enabling the selection of the optimum configuration. The results from this work demonstrate the benefit of objectively assessing the performance of nominally equivalent units in selecting an optimum configuration that best satisfies the performance criteria.

Jan 1, 2002

By M Baker

Biodiversity offsets are conservation actions intended to compensate for the residual, unavoidable harm to biodiversity caused by development projects. The use of biodiversity offsets in the context of mining has significant potential for enabling mining to take place in areas with biodiversity values, where it would not otherwise be possible to meet the relevant legal tests under the Resource Management Act 1991, and potentially the Conservation Act 1987. This paper looks at the concept of biodiversity offsets (and environmental compensation generally) both in New Zealand and internationally, and considers how lessons learned overseas may be adapted for this country. In New Zealand the practice of biodiversity offsets and environmental compensation is ad hoc and variable. The challenge with biodiversity offsets is to establish a transparent and coherent means of identifying the overall priorities and objectives of adopting such an approach, as well as how the relevant values are measured and protected. Establishing a methodology for quantifying biodiversity value, and the need for clear policy guidelines on biodiversity offsets are identified as key areas in need of wider discussion.

Jan 1, 2007

By D van der Wal, R Dobbe, K Moeller

"Ore mineralogy and texture are primary variables controlling mill recovery efficiency in flotation plants. However, tracking daily variations of key mineralogical characteristics such as species-by-species liberation is not possible with current on stream analysers and assay lab techniques. In addition, traditional plant mineralogical analysis limited by long data turn-around times from central analysis laboratories typically provides only a time-averaged view of mill performance, e.g. by means of monthly composite feed, con or tailings analysis.This paper presents the results of a development and first field test of an on-site Automated Mineralogy solution (MLA or QEMSCAN) with the specific goal of monitoring recovery variation, ore quality and flotation performance on a mineral species-by-species and day-by-day basis, from up to twelve million direct particle observations per month. The trial was performed at a Pb/Zn-Ag operation in the US from November 2012 to April 2013. The focus of the study was three-fold: to validate the robustness of equipment and operational procedures for daily use by mine site technicians at a remote mine site to develop a methodology to boil down hundred-thousands of Automated Mineralogy particle data from size-by-size con and tailings samples to a couple of numbers meaningful to chief metallurgists to monitor recovery trend changes and correlate these to changes in the feed properties and/or flotation efficiency.The study focused primarily on the Pb/Ag rougher-concentrator circuit. Ten polished blocks of two and three size fractions of con and tailings were prepared by mine site technicians during a daily twelve hour shift. Eight hours of daily measurement time by the instrument revealed an estimate of the dayÆs recovery performance, ore quality and flotation performance for Freibergite (Ag-species) and Galena (Pb-species), within 36 hours from initial sampling. Data quality was assessed by means of calculated versus measured assay reconciliation. Cumulative sum curves of recovery performance, ore quality and flotation performance reveal trend changes with a frequency of 1 to 4 weeks. These were correlated to cumulative sum curves of e.g. locked and slimed particle classes of the mineral species of interest, attempting to identify a possible root cause of recovery performance trend changes. Systematic over-grinding and flotation chemistry issues were the primary causes of below average plant operations during the trial.CITATION:van der Wal, D, Dobbe, R and Moeller, K, 2013. Development of an on-site mineralogy solution for metallurgists, in Proceedings MetPlant 2013, pp 126-132 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 15, 2013

By M Elias

Management of risk has always been an integral part of successfully executing engineering and construction projects although formal recognition of the discipline of risk management is a relatively recent development. This paper describes the establishment and application of a proprietary business risk management framework for FluorÆs global engineering and construction business.

Jan 1, 2003

THE Company's smelting equipment consists of three blast furnaces, supplied with blast from two sets of vertical piston blowers, each capable of delivering 8000 cub. ft. of air per minute at a pressure of 60 oz. per sq. in. Each blower is belt-driven by a 1:30 h.p. motor. The maximum speed of the blowing engine is 35 r.p.m.No. 1, the largest of the three blast furnaces, has a crucible area of 49.5 sq. ft., and measures 11 ft. 6 in. x 5 ft. at the tuyeres.From tapping floor to feed floor measures 35 ft. 9 in., and holds, when full, 100 tons of charge. Blast enters through thirteen 3-m. tuyeres at 60-oz. pressure. Working normally, this furnace is capable of treating :300 tons of charge, exclusive of returned slag and coke, per 24: hours, with an output of 100 tons of lead. Tapped slag flows into a C.l. forehearth mounted on wheels, where any lead and matte is caught, and the slag overflows into a 3-ton cast-iron pot, in which it is drawn away by an electric locomotive and poured over the dump.

Jan 1, 1918

By LeJuge G. E, McKenzie C. K

Innovative mining and blasting techniques were demanded at the Richmont Mines, Francoeur Mine in Quebec, Canada, by a narrow, shallowly dipping high grade gold ore body. The ore body being mined occurs as a thin tabular deposit varying in thickness between 1.5 and 3.7 metres, and dipping at 36¦. The mine proposed experimenting with open stoping techniques using small diameter drill-holes. The hangingwall required progressive, full face rockbolting after each production blast, utilising a specially manufactured machine which provided access to the hangingwall for both scaling and bolting. Blasted material is mucked from the stope by scraper and hoisted directly to surface without benefit of primary crushing.

Jan 1, 1992