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Research and Application of Vertical Screw Stirred Mill

Sep 13, 2010

Study on Oil Agglomeration Flotation for Deinking

Sep 13, 2010

The Ngakuru zeolites are located about 20 km south of Rotorua and comprise a number of deposits dispersed along several fault lines. Relatively recent volcanic activity (250,000 years ago) resulted in ash depositions that vary in depth and mineralogy. Subsequent variable thermal alteration intensities generated predominantly clinoptilolite and mordenite zeolites with a range of physical characteristics. Typically the zeolites have low density (650 kg/m3), have high liquid (60% of dry weight) and odour absorption characteristics, and a high affinity for soluble cations (CEC =: 100 meq/100 g). Traditional kitty litter and oil absorbency markets are being expanded. New opportunities in waste and potable water treatment, organic and synthetic slow release fertilisers, use as a light weight aggregate for speciality concretes, and pozzalome activity are currently being researched.

Jan 1, 2000

Grinding and Flowing Investigation on Dry Stirred Ball Milling in Order to Determine the Influence of Grinding Aids Huge difficulties of the great ultra fine ground material production in dry stirred ball mill are the cohesion and agglomeration of the particles. During grinding the material stick on the grinding wall and the grinding media furthermore the grinds start cohere, making aggregation and agglomeration to appear. Due to these effects the particle size will not decrease after a certain value during grinding and the energy demand increases significantly. According to experience on fine grinding in ball mill, it is well known that these effects can be reduced with the use of grinding aids. The influence of grinding aids has three different effects: due to the adsorption strength reduction (Rebinder effect) the grinding resistance of the material decreases; the surface energy diminishes and the agglomeration liability decreases; and the flow properties of material improve. The aim of this study is to investigate the flow properties of fine grinds and the effect of grinding aids on flow properties in case of dry stirred ball milling. In addition, the influence of grinding aids was investigated based on the particle size distribution and specific surface area of grinds and the specific energy demand of grinding. The examinations were carried out with three different model materials (limestone, clinker, quartz) using the usually applied grinding aid. The flow properties were measured by the Jenike shear cell; the particle size distribution and specific surface area were measured by laser particle size analyser (Fritsch Analysette 22), grinding energy demand was measured with microcomputer controlled digital energy meter. It can be said that under certain measuring circumstances the influence of grinding aid on flow properties can be demonstrated by Jenike shear cell, so the grinding result is in correlation with the flow properties of grind.

Sep 13, 2010

By B M. Wilson, B J. Turner, S Sinclair, R J. Buerger

The Trident Gold Deposit is centred on the historical Higginsville Mining Centre, between the world class gold centres of St Ives (+15 Moz) and Norseman (+6.5 Moz) in Western AustraliaÆs productive eastern goldfields. It lies towards the southern end of the Norseman-Wiluna Greenstone belt in the Archaean Yilgarn Craton. The current in situ resource for Trident is estimated at 840 000 ounces, with production to date in excess of 500 000 ounces.Trident is hosted primarily within a thick, weakly differentiated gabbro with subordinate mafic and ultramafic lithologies and comprises a series of north-northeast trending, shallowly north plunging ore zones. The deposit comprises two main mineralisation styles; thin, lode-style, nuggety laminated quartz veins (Athena and Artemis) that formed along major shear zones primarily at the contacts between the various mafic and ultramafic lithologies; and large wallrock-hosted ore-zones comprising sigmoidal quartz tensional vein arrays and associated metasomatic wall rock alteration (eastern zone, western zone and Apollo) hosted exclusively within the gabbro.The thin laminated quartz vein lodes are important to the Trident Gold Deposits production profile as they constitute 33 per cent of the metal from only 14 per cent of the tonnes. The delineation, grade estimation and extraction of these lodes require a disproportionate amount of geological and engineering input due to the small scale variability in width, grade and direction. Over time, a robust and thorough process has been developed at the Trident Gold Deposit to understand and then successfully mine these complex mineralised systems.CITATION:Sinclair, S, Wilson, B M, Buerger, R J and Turner, B J, 2012. The mining industry needs to be shaken and stirred, in Proceedings Narrow Vein Mining 2012 , pp 155-166 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 26, 2012

By A Tinnelly

Land disturbed by alluvial gold mining should be restored to a capability or productivity as good as that which existed prior to disturbance.   Effective rehabilitation requires detailed planning prior to mining and must also be closely integrated with the mining operations.   The main constituents of a rehabilitation plan: description of existing site conditions, choice of final land use, establishment of final landform, water management and erosion control, soil reconstruction, revegetation and management of rehabilitated land are briefly described.

Jan 1, 1989

On Kinetic Coupling in Meso-Scale Phenomena in Mineral Froth Flotation

Sep 13, 2010

By D Craw, J Pope, B Peake

Southland contains over 70 per cent of New ZealandÆs recoverable coal resources, and an investigation into the potential effects of coal mining on SouthlandÆs water resources is therefore of interest. This paper investigates pit-lake water quality in relation to current mining activities within the sub-bituminous coal and lignite deposits of Southland.   Water quality data was collected from pit-lakes in sub-bituminous and lignite deposits from October 2005 to March 2006. After periods of settled weather, turbidity increased with depth at the sub-bituminous pit-lake (10 - 21 NTUs from 5 - 30 m). In the stratified sub-bituminous pit-lake in March 2006, heavy rainfall caused higher turbidity in the epilimnion than the top of the hypolimnion (20 NTU vs 13 NTU) reflecting surface water runoff (up to 1993 NTUs) and epilimnion mixing. In contrast, turbidity at the lignite sites was variable due to the shallowness of the lakes, but noticeable increases following disturbance and adverse weather were recorded. High turbidity at the sub-bituminous deposits was attributed to the presence of clay minerals such as kaolinite whereas turbidity at the lignite sites was more likely short term and a result of heavier minerals such as quartz.   Trace element concentrations at both sites were low when compared to mine waters in other coal areas in New Zealand and no samples exceeded ANZECC water quality trigger values for 80 per cent species protection. Pit-lake water pH levels were lower and more variable in the lignite deposit (4.18 - 7.30 vs 7.24 - 8.98 in the sub-bituminous deposits). In the lignite pit-lakes, higher concentrations of trace elements (eg Dissolved As - 0.034 ppm and Dissolved Mn - 1.09 ppm) and lower pH (ÿ4) were observed at the bottom of active pits compared to inactive pits. It is possible that quartz pebble conglomerates containing sulphide minerals within the lignite seams are responsible for this.   Further investigation into the mine waters, waste rock and lake sediments will help get a better understanding of the results observed and long term processes that occur.

Jan 1, 2006

With the advent of the resources boom in the late 1960s most of the larger scale resources projects in Australasia were commissioned on an æowner miningÆ basis, where the mine owners owned and operated the primary mining equipment. Then, in the 1980s with the arrival of the gold mining boom in Western Australia and elsewhere, a change occurred û most of the mining activities were carried out on a contract mining basis. Over recent years, however, there has been a marked trend amongst larger Australasian open pit mining operations back towards owner-controlled and operated mining operations. The reasons for this are many and are addressed in the paper, but centre on the concept of the owner being prepared to assume more of the mining risk in exchange for the advantage of not having to pay a contractorÆs profit margin. Where mining contracts are entered into, the older æschedule of ratesÆ format is being replaced with less adversarial and more entrepreneurial contract alternatives involving operating cost and risk sharing in a spirit of æfair dealingÆ. Leasing and maintenance issues have also been influenced in recent years by the advent of more flexible contract arrangements with equipment suppliers. Group purchasing has also had some influence for project operators. For many mine owners, the optimal risk management profile involves a practical offsetting of the assumption of mining risk on the one hand, against the removal of litigation risk and potentially reduced operating costs on the other. Potential pitfalls may arise where equipment size and type requirements vary with time or where manpower management, mining flexibility, job skills or safety exposure factors are relevant. These issues are commented on in the context of some well known examples, and an update is provided on contract mining versus owner operation in large scale Australasian open pit mining generally.

Jan 1, 2002

By D Kotzen

Online cyanide analysers have been successfully used to control free cyanide in the gold/silver leach process for over 15 years. Use of such analysers leads to cyanide savings and improvement in recoveries. Plants with leach cyanide analysers show both lower and more consistent cyanide levels in tailings. Cyanide code compliance requires meeting residual cyanide targets in tailings. Monitoring and logging of the residual cyanide in plant tailings and effluent is required. Meeting targets may require cyanide recovery/destruction processes to be implemented. The operating cost of destroying cyanide is often the same order of magnitude as the cyanidation cost. Various cyanide destruction and/or recovery processes are reviewed. Choice of a process consistent with the environmental and operational requirements is illustrated. Online weak acid dissociable cyanide (CNWAD) analysers have recently been developed and introduced on gold plants. The application of a WAD 1000 online CNWAD analyser at a large gold plant is presented. The analyser ensures code compliance, reduces cyanide destruction process operating costs and forms a historical record of CNWAD values in tailings.

Jan 1, 2007

Gold mining in Australia and globally has a long and variable history. In recent years, due to ongoing public concern over long-term environmental impacts, the mining industry globally has been moving towards a more sustainable framework, presented as the æMining, Minerals and Sustainable DevelopmentÆ (MMSD) framework at the Johannesburg Earth Summit in 2002. There are a number of fundamental issues and concerns with assessing the sustainability of mining. Firstly, long-term trends show that ore grades for almost all metals and minerals will continue to decline (some rapidly so), increasing waste rock is being produced due to the trend towards large-scale open cut mining and more complex ores are now commonly being developed. The impact of these trends on the resource intensity, or unit cost, of gold production is of major concern as it could lead to an increase in energy, water and reagent consumption and greenhouse emissions per unit gold produced. A detailed compilation of these fundamental sustainability indices for gold mining has been undertaken, and is presented with respect to indices over time, ore grade and ore throughput. A clear observation is that the resource intensity of gold mining is extremely sensitive to the ore grade, with energy, water and cyanide consumption and greenhouse emissions rising significantly as ore grade decreases. Based on the gold ore resources at operating mines and other known gold deposits, it is most likely that the average gold ore grade will continue to decline, leading to increased resource intensity and consequent environmental impacts (assuming no breakthrough new technologies occur). These findings are of major importance to understanding the sustainability of gold mining. The final judgement of the sustainability of gold mining therefore must take into account the sensitivity of the ore grade in the resource intensity of gold production.

Jan 1, 2007

Improvement of Phosphate Ore Flotation Performance Through Sized Flotation

Sep 13, 2010

Correlation of Air Recovery with Thin Film and Froth Stability in Flotation

Sep 13, 2010

Pilot-Plant Testing of Ammoniacal-Cyanidation for Gold Recovery from Copper Gold-Bearing Ore The results of pilot-plant tested ammoniacal-cyanidation of gold recovery from copper gold-bearing ore are presented in this paper. This ore is from a deposit of Russian Federation with gold and copper grade 9.5 g/t and 0.4 per cent, respectively. Copper is largely present as malachite and azurite. The presence of chalcopyrite and bornite is also observed. In order to recover gold, gravity is recommended. Two options of ammoniacal-cyanidation using leaching of gravity tails, CIP and filtration, were tested. It was found that ammoniacal-cyanidation using filtration of leaching tailings and recycled solutions is the most optimal option. The proposed flow sheet provides for 89.7 per cent gold recovery from gravity tailings at the consumption of NaCN 0.9 kg/t and (NH4)2CO3 7.5 - 9 kg/t. Compared to conventional cyanidation, this technology decreases the consumption of sodium cyanide from 4 up to 0.9 kg/t at the same gold recovery. It can be recommended for the treatment of copper gold-bearing ores with the similar composition.

Sep 13, 2010

Application of Kriging in Approximations of Grained Materials Characteristics Distribution Functions

Sep 13, 2010

The New Zealand Minerals Industry is small but growing. Over the next 10 years it will be facing stiff international competition for skills to support this growth, particularly from Australia who are forecasting that a further 70 000 people will be employed by 2015.   The value of commodities mined and quarried in NZ continues to increase; and the value of coal, metals and industrial minerals production reached $1.505 billion in 2006, an increase of 15 per cent on 2005. Production increases will continue à. Latest Crown Minerals statistics show that national prospecting and exploration expenditure rose to $29.9 million in the year ended March 31 2006 û an increase of 46 per cent from the $20.4 million spent in the March 2005 year. The equivalent 2001 year expenditure was only $2.48 million.   The industry already experiences difficulty in recruiting the people it needs with ongoing demand for skilled underground miners, trades people, and mining professionals. This discussion paper will outline the national context with regard to labour, skills and training. It will suggest options and provide an opportunity for conference participants to discuss the way forward.

Jan 1, 2007

A major problem in open pit mine planning is to determine the optimum pit limit of the mine. The optimum pit limit is the one with maximum discounted net profit and satisfies technical conditions. A number of optimisation techniques have been proposed for determination of pit limits. Among these techniques, those based on graph theory are suitable to solve the three-dimensional (3D) problem. In this paper, two maximum flow methods named, Dinic's algorithm and Push-Relabel algorithm have been used to find the optimum pit limit of an iron ore mine. This method has been implemented in Gol-e-Gohar iron mine in south east of Iran in order to find the final pit limit. Issues, like properties of the mine and orebody, are studied. These properties include wall slope, sulfur and phosphor grade restrictions. The result shows that these properties have significant effect on the determined pit limit.

Dec 6, 2010

The Dynamics and Thermodynamics of Absorbing Lithium of Ion Sieve Preparing Pollymetallic Nodules

Sep 13, 2010

Although small scale mining is regarded by many as of historical value only, this kind of mining activity is still much more widespread than is usually assumed. It has been estimated that it produces as much as ten per cent of the global mineral output. More significantly this figure is often much higher for many of the developing countries of Africa, Asia and South America, signifying the relatively greater contribution of small scale mining to the economies of those countries. It is also noted that small scale mining has always been a feature of mineral production in New Zealand and Australia. An attempt is made to define small scale mining, and the factors determining the suitability of small scale mining operations are discussed. The state of the art in small scale mining is reviewed and the author endeavours to rationalise the important parameters which contribute to successful small scale mining operations and discusses how these parameters may be optimised. The benefits of small scale mining to the mining industry as a whole and to the community at large are outlined. The paper concludes by emphasising the necessity to maintain small scale mining and 'explores' its future 'prospects'.

Jan 1, 1990

Application of the Anaconda Simplified Work Index for Multiple Test Sizes Vale uses Bond Work Index measurements extensively in a number of applications. The Bond Work Index is usually a good parameter for checking scale up procedures when sizing ball mills, as well as the basis for variability analysis whenever drill core data is available. It is typical to measure between 100 and 150 Bond Work Indexes, depending on the deposit characteristics. The Bond procedure is relatively complex and time costly. It also requires relatively large amounts of sample, which are very expensive to be obtained. The benefits of the Anaconda simplified procedure are: considerably smaller sample requirements and laboratory time. This makes it very much attractive at Vale's development centre, including geometallurgical mapping, operation efficiency control, mine to mill, etc. The Anaconda simplified procedure was implemented and evaluated at Vale's Development Centre using a number of ores and several samples of each ore totalling more than 190 measurements. The Anaconda simplified method was calibrated for several test sieves and a correlation for any test size was determined for Vale's test mill. The calibration was also extended for two sample top sizes. The relative error of the simplified procedure was found to be in the range of nine per cent which is within the expected error Bond standard procedure. The implementation of the Anaconda method at Vale's development center has been used with great success over the past years in several green field, brown field projects and operating plants.

Sep 13, 2010