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By G B. Siddall

The paper examines the current state of equipment and circuit design, with reference to Australian practice. Following a review of the changes in milling applications over the last 15 years, developments in mill design are examined. Current issues include trunnion versus shell support; drive type and economic analysis for comparison of the various systems; the efficiency of the mill discharge system for slurry and pebble removal, and lining configuration. Peripheral problem areas such as pebble crushing and classification are briefly examined. Circuit design issues are reviewed. The decision to modify the traditional primary crushed feed is examined with reference to recent and proposed installations. A retrospective look at fully autogenous installations and their successes is presented, and current views on increasing throughput are assessed. Finally, future developments are anticipated in mill design and control, and competing processes are identified.

Jan 1, 2002

In recent years, wide consideration has had to be given to methods of improving the condition of the mine environment in many coal mines, and significant developments and changes have evolved. Thus even after substantial increases inòair flow rates at the working place (they have increased over three fold in the last generation), environmental conditions have arisen for which it has been necessary to introduce or consider: i) additional ameliorative measures, such as good housekeeping; ii) layout changes: such as Y or Z layouts; iii) homotropal ventilation; and iv) air conditioning. In certain countries, consideration has been given also to: v) additional payments reduced working times; vi) heat acclimatisation programmes; and vii) the use of cold or cooling suits At many hot and humid mines, the principal benefits from adopting (i), (ii) and (iii) have already been realised. At such mines,

Jan 1, 1983

By Gao H

Based on the author's research and plant practice experience of the last decade, several technological approaches have been developed to increase the recovery of gold and silver associated with sulphides. This paper gives a general discussion of some technological problems encountered in this area in five aspects and introduces the different approaches employed in three typical mineral processing plants to increase recovery of associated gold and silver. On the basis of studying occurrence characteristics of gold and silver minerals in sulphide ores and of determining loss locations of gold and silver on flotation process, a remarkable improvement on the recovery of gold and silver in all these three plants was made by choosing proper grinding fineness, using combined collectors of good selectivity, properly decreasing the grade of main metal concentrates, making reasonable arrangement of the products of main metals, or a combination thereof.

Jan 1, 1993

During the past three years there have been several parties prospecting for oil in the Stat6 of Queensland, and It was: gratifying to read the newspaper headlines last Christmasabout the discovery of oil in the Moohie Nol Well. This discovery was not only a welcome Christmas present for Australia but marked up another success for the seismicmethod in exploration for oil.The purpose of this paper is to discuss the operationaI aspects of seismic work in Queensland with-emphasis on shot-haledrilling. The paper is based upon the experience of one particular seismic survey which began in December of - 1959 and is still inoperation. This survey is being conducted by the Petty Geophysical Engineering - Company of San Antonios, Texas, and the Queensland area involved is in the general vicinity of Quilpie, Dlackall and Charleville.

Jan 1, 1962

By Torrance AC

A joint research programme conducted by BHP Central Research Laboratories and Du Pont Wesfarmers Pty Ltd examined the effect of the size of cast primers on the run up and steady state detonation veloci- ties of ammonium nitrate based explosives as a function of blasthole diameter. Both continuous and point to point velocity of detonation meas- urement techniques were used. The field trials examined a number of the Du Pont HDP series of primers in conjunction with ANFO, emulsion and watergel explosives. Results indicate that the run up velocity of 187mm diameter ANFO charges is negligible using cast primers as small as 150g. owever, emulsion and watergel explosives did exhibit run up in both 187 and 311mm diameter blastholes, independent of the size of primer. This could last from 7 to 10 blasthole diameters.

Jan 1, 1988

By Isokangas T. A

With some two-thirds of the production exported, coal mining prac- tices of the last few years in Australia have been much influenced by the decline in the price received. It became essential to improve efficiency and rationalise operations. Trends in underground practice vary. On the one hand many additional longwalls have been installed and most recently the results achieved by them have shown a significant up-turn; this may be correlated more with increases in equipment capacity than with utilisation which has altered little during the past six years. Varied constraints remain affecting cur- rent and future longwall operations. On the other hand a number of mines have been closed whilst others have sought to improve results by various installations including miniwalls, shortwalls, and use of continuous haulage and mobile breaker line sup- ports. All mines continue to review working practices.

Jan 1, 1988

By M McDonald

KiwiRail has a goal of significantly improving passenger rail services to west Auckland, as part of its DART (Developing Auckland’s Rail Transport) suite of projects. The New Lynn Rail Trench (NLRT) project was a significant component of this work. The NLRT project facilitates essential doubletracking of the Western Auckland line, and provides a new commuter transportation hub within a busy town centre.The 1.5 km stretch of track through the New Lynn town centre has bisected the township for over 80 years. Double-tracking the line provided the opportunity to grade-separate road and rail, which would help to re-connect both sides of the township and enhance public amenity and safety.KiwiRail employed an Early Contractor Involvement (ECI) procurement model engaging a consortium comprising Fletcher Construction, Beca Infrastructure and Synergine to develop a Design and Construct solution.With weak soil conditions and high groundwater levels, a diaphragm wall construction method to form the trench walls was selected as the best solution. Further challenges to construction included working within a narrow rail corridor constrained by buildings along much of the boundary, and a requirement to keep the existing line open for rail services. Detailed construction planning was required to ensure rail and construction safety in a constrained space whilst building the trench walls, propping these walls during excavation, and constructing the base slab in the most efficient way possible.This paper will detail the geotechnical conditions and the additional constraints that made this rail trench a challenging structure to design. It will also describe the fi nal design and construction methodologies that were employed, that allowed very successful completion of the project.Additionally, this paper will review the design and construction lessons applicable to the current Victoria Park Tunnel project, and indeed for all future cut and cover tunnel projects in the Auckland isthmus.

Mar 8, 2011

By R R. Lovel

In this paper, life cycle assessment methodology has been used to assess the variations in water use associated with different metal production and processing routes and provide insights into the value derived from water usage in the minerals sector. Using water consumption data derived from the literature it has been shown that the æcradle-to-gateÆ water consumption (or embodied water) for production of the various metals considered in the study ranged from 2.9 m3/t for steel up to 252 087 m3/t for gold. The results largely reflect the grade of the initial ore used to produce each metal, and can be approximated by the following equation: W = 167.7 G - 0.9039 where: W = embodied water (m3/t refined metal) G = grade of ore used to produce metal (per cent metal) The study showed that indirect water consumption in the metal production life cycle, in particular that due to electricity generation, can make a significant contribution to the embodied water value, eg aluminium production. When expressed in terms of m3/t ore, the results for all metals considered indicated that the embodied water is roughly, on average, three times the water consumption of the mining and concentration stage. It was also shown that the economic value per m3 of water consumed for the minerals industry exceeds that for the agricultural and industrial sectors, supporting the view that allocating water resources to the minerals industry has a strong underlying economic basis. Water reforms currently taking place in Australia aim to address issues such as competition for water access, reduced security of supply and increase in cost. Consequently the minerals industry, along with others, can be expected to come under increasing pressure to reduce fresh or raw water use and to integrate water use across sectors. While water recycling is an obvious candidate to help reduce water consumption in the minerals industry, issues such as water quality, among others, will influence the extent to which this can be achieved. In addition, wastewater volumes can be minimised using techniques such as pinch analysis to establish and use the minimum water requirement for the process. The use of dry or near-dry processing technologies, for which the demand for water is small or zero, may be a more radical solution to the water consumption problem; however, it is possible that the introduction of dry processing would bring with it a new set of problems, including dust.

Jan 1, 2006

By T Davis

Cameco Corporation operates the high-grade 140 tpd fly-in/fly-out underground McArthur River Uranium Mine in Northern Saskatchewan in a joint venture with Cogema Resources Inc. Reserve grade is in excess of 20 per cent U3O8 with current mining grade averaging 16 per cent U3O8. Due to the high radiation potential of the ore, the non-entry mining method of raiseboring was chosen to minimise worker radiation exposure potential. The raisebore and extraction horizons are located in waste rock with the orebody located between horizons. Ore produced by raiseboring is delivered by LHD to an underground SAG mill and is then hydraulically hoisted to surface receiving facilities after underground thickening to 50 per cent solids by weight. Concrete backfilling is utilised. The orebodies at McArthur River are adjacent to water bearing sandstone. Ground freezing is therefore employed to isolate the ore from this water bearing ground. Calcium chloride brine at -35¦C is circulated through a series of cased boreholes to establish freeze walls up to 25 metres in thickness. At 18 000 000 lb of low cost U3O8 production per annum, McArthur River ranks as the worldsÆ largest uranium mine. Over 50 per cent of the workforce resides in this sparsely populated area of Canada with approximately 40 per cent being of aboriginal ancestry. Site operations must cater for winter temperatures as low as -50¦C.

Jan 1, 2002

By J-P Franzidis

A technique for determining the recovery of attached particles across the froth phase in flotation that relies on measuring the rate at which bubble-particle aggregates enter the froth is used to investigate the selectivity of attached particles across the froth phase. Combining these measurements with those of other techniques for determining the froth recovery of attached particles provides an insight into the different subprocesses of particle rejection in the froth phase. The results of experiments conducted in a 3 m3 Outokumpu tank cell show that the detachment of particles from aggregates in the froth phase occurs largely at the pulp-froth interface. In particular it is shown that the pulp-froth interface selectively detaches particles from aggregates according to their physical attributes.

Jan 1, 2005

By A Murphy, D Lauder, J Miranda

Minera Alumbrera Limited operates the Alumbrera concentrator, treating a nominal 80 000 tpd of porphyry gold/copper ore. It is located in Argentina, 1200 km north-west of Buenos Aires in Catamarca Province, at an elevation of 2550 m above sea level. Treatment facilities consist of crushing, SAG and primary ball mill grinding circuits, rougher flotation, ball mill regrinding, gravity recovery and cleaner flotation. It is one of only a small number of concentrators in the world, which uses Jameson Cells alone for cleaner circuit flotation. Plant design was started in June 1995, with commissioning commencing in July 1997. Following a successful ramping up to design tonnages and recoveries, a number of options were reviewed to improve gold and copper recoveries. This paper concentrates on a detailed size by size flotation recovery project, commenced in May 1999. Utilising optical microscopy, scanning electron microscopy and analysis of surface chemistry it has allowed losses by size fraction to be quantified and options for enhanced recoveries to be developed. Coupled with extensive circuit surveys it has also provided an insight into previously unknown properties of Jameson Cell operation. Among these are unique residence time and bubble formation reactions to reagent and pulp flow variations, which has permitted a number of novel changes to the operation to maximise capacity and recovery.

Jan 1, 2000

By D Cohen, A Wurster

Many Southern African mining operations produce mine water which is beneficially and productively utilised on the mine sites and to support other water uses. Mine water treatment typically takes place within the context of integrated mine water management involving pollution prevention, waste minimisation, recycling and reuse as well as river discharges. Development of new and improved mine water treatment has focused on the neutralisation of metals removal, desalination of high sulfate waters and passive treatment. Mine water neutralisation processes now incorporate a combination of natural limestone and lime treatment, as well as features to maximise gypsum precipitation. The South African CSIR developed a suite of limestone-based neutralisation processes, which include reuse of CO2 and CaCO3 generated in the process. Desalination of high sulfate mine water is typically done using one of the following technologies:biological sulfate removal with different approaches to the handling of the sulfide generated in the process, and ultrafiltration (UF)/reverse osmosis (RO) treatment with different approaches to the handling and disposal of the brine. The current research and development focus is the separation and recovery of saleable products from the treatment residues and brine streams.

Jan 1, 2006

By E Ferrow, R Herbert, M E. Malmstr, M Fuchs

The study of microbial sulfide oxidation and oxidation rates of tailings requires the use of sterile control samples in laboratory experiments for comparison purposes. The need for sterile tailings sand is also apparent in the study of microbial communities and processes. This study compares six different methods with regard to sterilisation efficiency and investigates chemical and mineralogical changes in the samples as the result of sample treatment. In addition, the effect of sterilisation on mineral weathering rates is also studied. The efficiency of the different methods with regard to sterility is estimated by most probable numbers (MPN) of both sulfur and iron oxidising bacteria. The sterilisation methods that were compared are: washing with sterile water, washing with ethanol, applying antibiotics, repeated heating to 70¦C, autoclaving, and γ-irradiation. There are several possible drawbacks with the different methods, including the risk of an applied chemical acting as a substrate for micro-organisms in the system, and the risk of altering the tailings. The results show a substantial difference in sterilisation efficiency between the treatments. For example, autoclaving, repeated heating, ethanol and irradiation efficiently kill micro-organisms, rendering an undetectable amount of bacteria after one month of incubation, whilst washing with water exhibits virtually no microbiological effect, with a bacterial content comparable to the control. The use of antibiotics for sterilisation ranks intermediate: the lag-phase was twice as long in the antibiotics treatment compared with the controls. X-ray diffraction, optical and electron microscopy, M÷ssbauer spectroscopy, and mineral magnetism indicate no significant change in the bulk mineralogical composition. However, X-ray photoelectron spectroscopy analyses show that with some of the treatments, sulfides are partially oxidised, as indicated by the formation of sulfate and partially û oxidised sulfur species at the tailings surfaces. Aerated batch weathering experiments performed on sterilised tailings samples and untreated controls indicated that while the initial rates of element (S, Fe, Cu, Zn, Mg, Na, K, Ca) release may differ between the samples, over the course of ~100 days of experiment at pH 2 and room temperature, the rates declined toward a similar value for all samples. To conclude, there does not appear to be one perfect method for tailings sterilisation. Autoclaving and heating damage the mineral grain structure and oxidise the sulfide surfaces. Ethanol, antibiotics and rinsing greatly alter the pore water chemistry through the washing procedure. In addition, ethanol and denatured antibiotics might serve as a substrate and also, in the case of antibiotics, adhere to mineral surfaces thus obstructing chemical reactions. Irradiation seems to be the preferable method on an overall basis, although the formation of surface Fe3+ was suggested by M÷ssbauer spectroscopy.

Jan 1, 2003

Recent analysis of backfilling material has shown that a finer size distribution is preferable for stope filling. In order to increase crusher throughput and pit productivity, a reassessment of the quarrying operation was conducted. Part of that reassessment was a review of blasting practice. Six means of reducing the average muckpile fragment size were examined. Different blast initiation and charging options were compared, and patterns using smaller hole sizes were designed, analysed with the JKMRC 3x3o software, then drilled and fired. The ground vibration and face movement was recorded and compared. To determine whether the Kuz-Ram model could be used in an economic analysis of the quarry operation, the fragmentation distribution of the small diameter hole blasts was determined. Photographs of the muckpiles were taken and digitised. However subsequent analysis indicated that a satisfactorily large photo sample was only obtained from the smallest diameter hole blast. The Kuz-Ram fragmentation model prediction was found to be within the confidence limits of those results. An engineering and cost comparison between the blasts was made.

Jan 1, 1995

By L Torckler, J Hobbins

Favona is a blind low-sulfidation epithermal vein deposit in the Waihi Vein System approximately two kilometres east of the world class Martha Hill deposit that has produced nearly 6.8 M oz Au to date. The Favona epithermal system has surface expression in variously altered and mineralised hydrothermal eruption breccias forming a series of low hills that are windows through post mineral dacites and ignimbrites. The tip line of the Favona vein is about 50 û 100 m below surface with a steeply east dipping principal vein structure carrying numerous hanging wall splays in the upper flatter section and thickening down dip where the vein steepens. Host rocks comprise feldspar phyric andesite flows with minor pyroclastics. Although Favona has a strike length in excess of 1000 m and vein widths up to 25 m over a vertical range in excess of 400 m it was only recently discovered after nearly thirty years of exploration by various companies involved in the Martha Hill joint venture that operates the Martha Mine. Since discovery in 2001 a feasibility study based on 27.5 km of diamond drilling in 83 holes has been completed reporting a reserve of 1 Mt @ 10 g/t Au against a resource of 1.8 Mt @ 10.3 g/t Au. Exploration is continuing with a further 20.5km of diamond drilling completed to date on nearby prospects.

Jan 1, 2004

By Dorricott M. G

Ballarat Goldfields NL is developing an exploration decline at Ballarat East using a Mitsui Miike S-125 roadheader. To-date, 530 in of advance has been achieved at an average rate of 16.1 m/week. Roadheader availability has averaged 94.3 per cent, and pick consumption has averaged 0.016 per m. Ground support has involved pattern rockbolting with split sets, 100 mm thick fibre reinforced shotcrete, and steel sets as required. The slower than expected advance rate has mainly been due to difficult ground conditions. It is expected that a further 970 in of decline will be mechanically excavated before a drill and blast system becomes more economical.

Jan 1, 1995

By R C, K L. Rees, J S. J van Deventer

In contrast with previously published models for the carbon-in-pulp (CIP) process, the model proposed in this paper incorporates film transfer, intraparticle diffusion, simultaneous leaching, preg-robbing, the loading of multicomponent species, and the effects of fouling and changing cyanide levels. The rationale behind this comprehensive model is that changes in fouling and competitive adsorption along a CIP cascade affect the profiles of gold loading. As it is impossible to quantify all these non-ideal factors, a method is proposed whereby an imaginary species is postulated so as to combine all the competitive effects. A plant survey at the Telfer mine has shown that the mass loss due to a gravimetric analysis of the fouled carbon could be used directly to quantify this competitive effect. The degradation and consumption of cyanide along the Telfer CIP cascade enhance the loading of copper on to the carbon, which should be taken into account when modelling the gold profiles. It appeared that the effect of cyanide itself on the loading of gold was negligible compared with its effect on the copper. Evidently much more research is required on this topic in order to optimise CIP operations exposed to constantly changing conditions.

Jan 1, 1998

By P Hogan, M Wells

Reflectance spectroscopy has become an established technique for mineral exploration and ore characterisation. However, there are few reported cases where the technique has been applied to the Hamersley Province channel iron deposits (CID). The Bonnie Creek CID, located ÿ140 km north of Newman in Western Australia, represents one of a number of CIDs recently discovered in the Hamersley Province. Reflectance spectroscopic analysis using the CSIRO HyLoggerÖ automated scanning system, in conjunction with X-ray diffraction and compositional analysis, was used to characterise and map the ore and gangue mineralogy in CID drill core. Using CSIROÆs spectral mineral characterisation scripts, it was possible to map the downhole distribution of the Fe-oxide abundance, hematite:goethite ratio and the gibbsite and kaolinite abundance. Spectral estimates of kaolinite abundance were found to be closely related to loss on ignition measurements at 650¦C and the spectral kaolinite abundance index provided a reliable estimate of the total weight percentage Al2O3 content. In addition, downhole HyLoggerÖ scanning of diamond drill core reliably mapped the distribution of kaolinite as supported by coincidentally elevated contents of alumina and silica. Furthermore, spectrally-derived estimates of iron oxide abundance were well related to assayed Fe wt per cent contents and use of the spectral iron oxide mineral index mapped the distribution of the goethite:hematite ratio, and demonstrated that material logged as high-grade ore in the Bonnie Creek CID was predominantly goethite-rich.CITATION:Wells, M and Hogan, P, 2013. Bonnie Creek channel iron deposits ore mineralogy - insights using the HyLoggerÖ technology, in Proceedings Iron Ore 2013 , pp 321-328 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By Cliff D, Harrison P. Hester C

During 1997 two different types of coal mine inertisation equipment were trialed in separate underground coal mines in Queensland.In April 1997 tests of the Polish developed GAG-3A inert gas generator were carried out at the Collinsville No 2 Coal Mine. These demonstrations indicated that the GAG-3A device was applicable in underground coal mines and that with respect to inertisation rate the device outperformed all other currently available techniques. The unit was assembled rapidly and operated safely during surface and underground trials and no mechanical problems were encountered with the device. The GAG-3A is not suitable for every fire scenario particularly if large volumes of fresh air are being drawn into the mine(where multiple units may be required), but with respect to the selection criteria developed by the Moura Implementation Process Task Group 5 criteria, the unit performed up to the specifications required.

Jan 1, 1998

By E Giles

Pike River Coal Limited (PRCL) is opening a new underground coal mine in the Paparoa Ranges north-east of Greymouth. To access the coal reserves, PRCL have had to build a 13 km access road through regrowth and virgin forest, and appointed McConnell Dowell Constructors Limited, with URS New Zealand Limited as their consulting engineers, to construct the final access link: a 2.3 km long, 5.5 m wide and 4.5 m high incline tunnel. This paper discusses the logistical issues of construction in an isolated pristine forest in mountain land and how they were addressed. It provides an overview of the 90 per cent complete tunnel and how challenging rock conditions have been mastered. It outlines briefly the remaining work which is construction of pit bottom workings where the mine infrastructure will be housed and construction of a 110 m deep, 4.0 m diameter, vertical ventilation shaft.

Jan 1, 2008