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By P Paredes, T Leaño, D Gajardo, C Tramón, S Peñaloza

The definition of an ore handling system and its consequent layout design is of crucial importance in cave mining projects. It not only represents the main driver in the production capacity and reliability of the mining system, it is also a fundamental variable in the footprint’s development time and cost.In recent decades, load-haul-dump (LHD) tramming distance optimisation through the allocation of several orepasses inside the footprint has been the most common practice in ore handling system layout definition at Codelco’s operations. Today, the improvement of existing technology, such as higher-capacity LHDs and jaw-gyratory crushers, and intensive preconditioning techniques to improve fragmentation allow the conceptualisation of simple and highly productive ore handling system layouts for wide caving areas that avoid the complexity and high cost of developing numerous orepasses inside the footprint.The initial macroblocks of the Chuquicamata underground mine project (PMCHS) consider an ore handling system layout in which LHDs dump into orepasses located inside the footprint area. The ore is then transferred into crusher chambers located below the production level, where it is crushed by jaw crushers and then conveyed to surface. In an effort to reduce development time and costs, a new ore handling system layout for the PMCHS experimental macroblocks was engineered using improved technologies and techniques in a simpler mining system. This paper compares the new ore handling system layout for the project’s experimental macroblocks with the traditional LHD-orepass layout in terms of production capacity, reliability, development time and cost.CITATION:Paredes, P, Gajardo, D, Leaño, T, Peñaloza, S and Tramón, C, 2016. Simplifying the ore handling system through the use of current technology at Chuquicamata underground mine project, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 571–584 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By V P. Elpatyevskaya, V S. Arzhanova

Main geochemical problems concerning the environment and mining industry interrelation are connected with the transformation of natural water chemistry by mining wastes. The investigation of many mines in Primorye, the southern part of the Russian Far East, showed that their mining waters have high concentrations of heavy metals and aluminium. Water acidity is primarily connected with the amount of acid-forming sulphide minerals in ores and also depends on the neutralising capacity of rocks. Considerable quantity of metals occur in the waters in dissolved form. Metal concentrations in mining waters exceeds the natural levels by two to five orders of magnitude and can't be reduced to the background levels even after multiple dilution. It is necessary to develop and put into practice new technologies so that to reduce the geochemical impact upon the environment.

Jan 1, 1995

It is well known that the ability to influence project value reduces significantly as planning progresses and decisions regarding project parameters are made. However, at the prefeasibility stage in particular, where one of the main aims should be to evaluate a wide range of options in order to select the best for more detailed further study, there is often a reluctance to spend the time and money needed to do this rigorously. This paper demonstrates, by a number of case study examples, how significant increases in value may be obtained by fully evaluating the combinations of alternatives for various project design parameters, including (though not limited to) mining methods, haulage methods, mining rates, processing methods and rates, sequencing of mining, and cut-off grades, with changes and upgrades over time where applicable. The additional value unlocked is typically orders of magnitude greater than the additional cost of the more comprehensive study. The dangers of misuse of simplistic sensitivity analyses and failure to identify how strategies might change in response to changes in external factors are also illustrated, and the importance of selecting the best ægrade descriptorÆ is discussed.

Jan 1, 2007

The assistance that can be gained by the use of aerial photographs in the geological examination of a mineral field is clearly illustrated by the results of a rapid reconnaissance survey of the newly-discovered Mount Fitton talc, deposits, situated in the north-eastern extension of the Flinders Ranges in South Australia.The talc deposits were found to occur about the margins of a large lenticular mass of dolomitic marble, interbedded with hornfelsic tillites and fluvio-glacial sediments of Upper Pre-Cambrian age. Aerial photographs show clearly the extent of the dolomitic marble on which the growth of a species of eucalypt-Eucalyptus Gillei-is prominently developed, and which assists in defining the limits of this relatively light-coloured formation. (See Fig. 1).Upon field investigation it was found that the talc, deposits are related closely to the margin of the dolomitic marble where the latter has been subject to minor folding and faulting. The deposits themselves have been formed by metasomatic replacement of schistose dolomite. The contact of the dolomite with the underlying and overlying glacial beds is also noteworthy for the presence of minor occurrences of copper, silver, lead and zinc minerals.An examination of photographs covering a wide area reveals an outcrop of a massive granite to the north-east of the dolomitic marble, Fig. 2, which was almost certainly responsible for the regional metamorphism of the dolomitic and glacigene sediments, and the source of the mineralising solutions.All these features, as well as the broader structural features of the area, which are extremely important in the understanding of, individual commercial depQsits, were quickly determined with the assistance of the photographs.It is useful, briefly to relate the procedure adopted in examining this recently developed field as an example which may be well worth following on other fields, even if exposures are not so clearly defined. The method to be outlined, of course, will be of maximum advantage. Where rock exposures are good, where the ore bodies are likely to be widely spread, and where such bodies are related to some major geologi-cal control. Typical of such deposits are pegmatitic, hydrothermal and related ore bodies associated with the periphery of an igneous intrusion, or ore bodies related to particular sedimentary horizons in a regionally metamorphosed province.Procedure.The first requirement is the preparation of a detailed reconnaissance geological plan of as large segment as possible of the potentially mineralised province. The use of aerial photographs is par...

Jan 1, 1950

An Evaluation of Froth Recovery Measurement Techniques

Sep 13, 2010

By P M. Outhwaite

Everyone present today is especially aware of the need for minerals in this society of ours. The words 'especially aware' were deliberately chosen because this is a meeting of the NZ Branch of The Australasian Institute of Mining and Metallurgy not a dilettante group such as some of our critics. Members of the Australasian Institute of Mining and Metallurgy knew that our great farming industry, our shelter, our transport and our energy supply, are largely dependent on a flow of minerals into this country despite the presence of large coal and natural gas reserves. Flow in was said because New Zealand imports most of its mineral requirements with all the consequential strategic and economic disadvantages. If the above statements are accepted by this gathering it would be a premise fairly stated that New Zealand has a great need to discover and develop minerals.

Jan 1, 1976

There are no large rivers in Western Australia capable of supplying water for processing magnetite ores. If sea water is used there are severe corrosion issues and the requirement to wash the concentrates with potable water. If groundwater is used there is a need to treat the water and sustainability is an issue for large projects because of potential drawdown of the aquifer.If sea water is desalinated the cost of the water is high because of the power requirement. At the same time the necessity to conserve water has lead to flow sheets where all of the tailings have to be filtered to minimise the water requirement.Managing the various water qualities and optimising water recovery and quality has resulted in optimising the water balance and issues meeting environmental obligations. Reverse flotation is a critical final step in reducing the silica level in the final concentrate and requires good quality water.

Jan 1, 2009

By K S. Fisher, J D. Pease

The installation of the George Fisher flowsheet in the lead/zinc concentrator at Mount Isa Mines Limited has recently been completed. The George Fisher flowsheet involved moving flotation capacity from the lead circuit to the zinc circuit and changes in zinc circuitry, changes in the reagent regime and increased regrinding capacity, using IsaMills, to regrind some streams to 80 per cent passing seven microns. The project was highly successful, delivering a five per cent increase in zinc recovery within a fortnight of commissioning. The George Fisher flowsheet was developed over six years. Laboratory work built upon the knowledge gained from investigating and processing the Mount Isa and Hilton orebodies. The engineering design and construction for the brownfield expansion of the existing lead/zinc concentrator had significant involvement from the operational, maintenance and technical personnel. Experienced personnel were seconded from the concentrator to the design and construction groups to ensure smooth integration of the new flowsheet into the existing concentrator with minimum downtime, and maximising the reuse of existing equipment. The combination of thorough design, good project integration with operations, and a good commissioning plan allowed almost immediate delivery of project gains. The project was highly successful, the full design improvements were achieved within two weeks, allowing the focus to move to developing future improvements.

Jan 1, 2000

By Kelsall D. F, Trahar W. J

The size by size batch flotation behaviour of copper activated sphalerite from synthetic mixtures with quartz was determined. In terms of recovery of sphalerite, the size fractions could be grouped into coarse, intermediate, and fine ranges. The behaviour of the coarse and fine ranges was significantly poorer than that of the intermediate range in both the extent and rate of flotation.Each size fraction had a fast and a slow floating component.The main effect of changing the copper sulphate addition was to alter the proportion of any size fraction which was fast floating. No correlation could be found, between the amount of copper on the spha:lerite andeither the flotation rate of the mineral or the amount of copper added to the system. It was found that fine particles did not appear to consume greatly disproportionate amounts of copper sulphate during conditioning. A modified conditioning procedure was found to lead to a higher rate of flotation and recovery of coarse sphalerite and to make poss1ble substantial savings of copper sulphate.

Jan 1, 1975

Predicting Flotation Response from Liberation Information

Sep 13, 2010

SOME notes on the works of the Electrolytic Refining and Smelting Company of Australia will no doubt be of interest to members of the Institute, more especially as much of the work is new to Australasia. As many of the members who may read this paper have not been in a position to visit works of this kind, and are consequently not thoroughly acquainted with all the operations carried on, the author has taken the liberty, in some cases, to enter into explanation which would otherwise be unnecessary. The works are situated at Port Kembla (New South Wales), about fifty miles south of Sydney, and are approachable both by rail and water. The Government has recently built a low-level jetty upwards of five hundred feet long, and intends installing at an early date an electrically operated portable crane to facilitate the handling of material to and from the boats. This will mean: a considerable reduction in the length of time that boats are laid up at the jetty. There are also under construction two breakwaters, which, when complete, will materially assist shipping operation...

Jan 1, 1910

By P N. Holtham

As part of a long-term study of titanium minerals processing being undertaken by the Julius Kruttschnitt Mineral Research Centre (JKMRC), techniques have been developed to measure the electrical properties of the various minerals. The measured values will be used to model the behaviour of the various minerals in high-tension roll and electrostatic plate separators. The resistivities of ilmenite, rutile and zircon from a number of Australian producers have been measured by applying a DC voltage across a test sample and measuring the resulting very small current flow. By appropriate design of the measurement cell and attention to the experimental procedure, reproducible resistivity values have been obtained, ranging from 106Ωm for ilmenite to 1013Ωm for zircon. However, the conditions of measurement are radically different from those under which electrical separation takes place. It is not certain that the measured values reflect the resistivities seen under high-tension separation, during which the particles are subject to a high intensity corona field. Consequently, an alternative technique for measurement of resistivity under conditions of corona bombardment has been developed. It is based on the experimental procedure of Castle and Yelle (1979) used to measure the resistivity of fly ash under the conditions occurring in electrostatic precipitators. This paper describes the development of the segmented ground plane measurement surface and a high-voltage switched resistor network which comprises the in situ resistivity apparatus. Results are presented comparing the measurements made under corona bombardment with those made using the DC measurement cell. The equipment has also been used to study the current distribution from a corona wire, as a function of high-tension voltage and wire-to-plane spacing.

Jan 1, 2001

By A M. Sardo, D E. Sinnett

This study uses the Q Method to examine how those living in former metal mining landscapes value this heritage and their preferences for the long-term management of mine waste. Such sites are often perceived as derelict or degraded, and of very little value. It is therefore assumed that their reuse, for example for development or recovery of metals, is likely to be beneficial. There are around 5,000 former metal mines in England and Wales, many of which are protected for their ecological, geological or cultural value. The Q Method is particularly suitable for issues where there is no consensus of opinion. We asked 38 residents of six mining areas in England and Wales to ‘sort’ a series of statements based on their resonance with the resident’s perspective; this is the Q sort. The statements covered a range of opinions of the mining legacy, its value and options for its management with a particular focus on the potential for metal recovery from the wastes. Analysis of the Q sorts revealed five perspectives on the mining heritage. All placed a high value on the cultural and ecological value of this heritage, however, they differed in their priorities for long-term management. For example, emphasis was placed on either nature conservation, cultural heritage, water quality or the opportunity for job creation through reworking the mines. Cutting across these themes there were also differing perspectives on the role of experts and local people in shaping the future management of the wastes. This research suggests that the views of local people are nuanced; they value their mining heritage but opinion is split on the most effective way to manage these sites especially where there is an impact on water quality.CITATION:Sinnett, D E and Sardo, A M, 2018. Former metal mining areas in England and Wales – local residents’ preferences for the management of wastes, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 126–134 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By L Torckler, R L. Brathwaite

At Neavesville gold-silver (electrum) mineralisation occurs in steeply-dipping zones of intense fracturing, brecciation and quartz veining within rhyolitic pyroclastics, carbohaceous shales and andesites. Hydrothermal alteration extends over an area of greater than 3 by 1.5 km. In rhyolitic tuffs, highly silicified zones containing quartz-adularia-illite assemblages are flanked by less silicified assemblages composed of albite, illite-montmorillonite and chlorite. The mineralogy and sequence of alteration are comparable with the alteration zones which envelop the steam-producing fissures of the active Wairakei and Broadlands geothermal fields. Primary fluid inclusions in quartz from five fissure veins in the Neavesville field show maximum homogenisation temperatures ranging from 220 - 260¦C and salinities of 0.0 - 1.1 wt per cent NaCl equivalent, which cover a similar range to actual measured temperatures and salinities in geothermal fluids at Wairakei and Broadlands. The age of the rhyolitic pyroclastics and related alteration and mineralisation is probably Pliocene and Neavesville therefore represents a fossil geothermal system. The intensely fractured zones containing the gold-silver mineralisation were probably produced by hydraulic fracturing generated by accumulation under pressure of hydrothermal fluid in blind fault zones. Study of fluid inclusions indicates that hydrothermal quartz associated with electrum was deposited under boiling conditions. High grade electrum mineralisation at Graces workings appears to be localised by reaction of hydrothermal fluid with sedimentary marcasite in black shale.

Jan 1, 1980

By M J. Kongas, K M. Saloheimo

This paper presents the art of on-stream particle size and elemental analysis used at iron ore concentrators, followed by the results and experiences from several sites.Online particle size analysis is rather common at medium- to large-sized concentrators. Online X-ray fluorescence (XRF) elemental analysis, however, is only used in some iron ore concentrators, while it is a routine practice in base metal concentrator plants. Online XRF analysis is applicable for process monitoring and control down to four to five per cent silica by measuring Fe assays accurately. With lower silica content, direct measurement of silica and other light elements is required. Some light element analysers that are based on the prompt gamma neutron activation analysis (PGNAA) method have been developed, but they have not performed up to expectations with slurry analysis. Other methods have been tried though these have not been used beyond prototype installations. Operating online light element slurry analyser installations are not common in iron ore applications.There is an economic incentive to mine lower and variable grade iron ore resources, which require concentration and removal of several impurities to produce high-quality concentrates for pellet production. Monitoring such operations by on-stream analysis has significant economic benefits, and there is a need to develop a dependable slurry online analyser for Si, Al, Mg and other light elements. The latest developments in slurry on-stream light element analysis are described.CITATION:Kongas, M J and Saloheimo, K M, 2013. Online slurry analysis for process control and monitoring at iron ore concentrators, in Proceedings Iron Ore 2013 , pp 303-308 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By Ashley P, Neale T

Alluvial gold was discovered on Sudest Island in 1888, and by 1893, an official production of 10 000 oz had been won by expatriate miners from shallow alluvial and colluvial workings. Hardrock sources were located and while one was developed at Mt Adelaide, production is unknown. Sudest Island comprises mostly phyllites and lesser coarse grained rocks which are cut by metamorphic quartz veins and basic (locally shoshonitic) intrusives. Sheared and altered basalts and serpent- inites represent are believed to be elements of an ophiolitic suite inferred to be associated with metamorphic core complex development and thus similar to tectonic environments on Misima and the D'Entrec- asteaux Islands. No epithermal-style quartz suggestive of a target similar to that on Misima Island has been identified on Sudest. A hardrock source for the alluvial and colluvial gold is interpreted to be metamorphic quartz veins similar to those in the Bendigo- Ballarat Zone of central Victoria, possibly remobilising gold derived from the meta- sedimentary and meta-igneous rock pile. The present focus is on development of a small scale alluvial gold mining operation in conjunction with exploration for hardrock targets. This latter programme remains at a reconnaissance stage.

Jan 1, 1991

By C Doblin

Any value addition to the mineral sands in the Murray Basin (Australia) will generate waste that needs to be disposed of safely. For example, conversion of ilmenite and synthetic rutile to titania (TiO2) pigment would generate large amounts of environmentally undesirable elements. Processing of U+Th containing zircon sands to zirconia or to higher purity zircon would generate a low-level radioactive waste. In this study it is proposed that one way to circumvent the waste problem could be to contain such waste in magnesium-based (Sorel) cements. Containment of waste in magnesium cements is an attractive idea especially for the mineral sand processing companies that could operate in the Murray Basin in the future, because the required magnesium oxide and magnesium chloride may be made cheaply from the saline waters encountered during mining operations. The magnesium cement production process is also far less energy intensive than the Portland cement production process. The results of this study indicate that mixing a waste stream with a slurry of magnesium cement before being discharged to the disposal area would contain the waste in a æconcrete-likeÆ structure, resistant to dispersion by wind and moderate rain. However, some loss of strength and increased leaching of impurities, Mg and Cl could take place in wet climate areas. Ongoing research is being concentrated to develop a new process for making water-resistant magnesium cement.

Jan 1, 2002

This paper reviews the current techniques employed in the prediction of subsidence and how they have been applied to partial extraction systems. The method using influence functions to describe the shape of the profile is investigated in detail and has been adopted to model the subsidence over workings in Huntly. It is compared with the profile methods developed in the United Kingdom and found to predict the subsidence profile more accurately than these methods.

Jan 1, 1991

By D Barclay, S Mercer, S Wright

Mine water management is often an afterthought in mine planning processes and can introduce significant risks to projects when studied as a stand alone component at a later stage in the mine design. Incorporation of a mine dewatering and pore pressure dissipation strategy in the early stages of mine planning is imperative in order to minimise constraints on the production schedule, to match designed pit slopes and maximise project value for an open cut mine option such as Olympic Dam. A risk-based mine planning approach was adopted during the project selection phase study whereby water management was introduced into mine planning, scheduling and the development of an operational strategy. Hydrological and hydrogeological studies and outputs were successfully integrated into the various iterations of the mine planning cycle during early selection phase to manage the potential water management risks associated with pit slope depressurisation and access to dry working conditions during rapid advancement of mining phases.An extensive network of vibrating wire piezometer sets and long-term depressurisation testing characterised aquifer conditions and demonstrated that hydraulic connectivity exists within the geological profile due to the presence of structures and resource drill holes which enhance vertical connectivity. This connectivity, along with underdrainage from mining activities contributes up to 100 m of depressurisation in low permeability units.A pit dewatering strategy incorporates the mine planning schedules and accounts for operational constraints as to the location and development of the dewatering wells, storages and pipelines. Numerical modelling generated a range of likely pit inflows and dewatering requirements with the average initial dewatering discharge likely to be 150 L/s and reduce quickly to 50 L/s after five years, depending on the premine schedule.Coupled hydrogeological and geotechnical assessments were also carried out as part of the mine planning cycle and indicate that successful dewatering will go a long way to reduce the pore pressures within key geotechnical units during the rapid mining phase where around 300 m of cover sequence is stripped in five years. However, the residual storage in the primary aquifer and the residual pore pressure in underlying low permeability units will need to be dissipated (in-pit horizontal holes) as the pit floor advances. Pit slope design angles are sensitive to depressurisation and dewatering and up to 70 per cent depressurisation of key geotechnical rock units are required. Whilst an accelerated program of aquifer dewatering supported by lithostatic unloading should drive rapid depressurisation in the lower permeability units, intervention is anticipated in key geotechnical units such as the Tregolana Shale and volcaniclastics. The extent of induced drainage will ultimately depend in part upon the mining rate and geotechnical stability requirements. Practical operability testing addressed the potential for operational constraints to mine depressurisation activities such as congestion and mining schedule development within the pit and identified that depressurisation drilling can be achieved even with reduced access availability. Mine operations and planning groups established design criteria and considered the likely inoperable periods following rainfall events of seven to 14 days to manage the base surge and minimise impact on production. In-pit surface water management options to minimise operational disruptions during and after significant rainfall events were estimated used a stochastic approach.

Jan 1, 2009

This technical note describes a problem with WANG82, a ventilation network analysis programme. The problem was highlighted by Renison Ltd when using the programme on large, complex networks. Under certain circumstances the programme produced incorrect results or failed to converge to a solution.

Jan 1, 1986