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By J P. Wyethe, D P. Padayache, B R. Green

The development of an ion exchange process for the recovery of vanadium from solutions containing low concentrations of vanadium and/or slurries is discussed. The process can be used to improve overall vanadium recovery throughout the plant, and/or to reduce the vanadium concentration of waste materials prior to their disposal. The development of the process on a laboratory and miniplant scale is discussed, and includes:selection of a suitable resin with the desired loading and elution characteristics; laboratory-scale testwork to evaluate the use of the resin in both resin-in-pulp and fixed bed configurations; recovery of a high-value vanadium product from the resin eluate; and a preliminary techno-economic assessment of the financial viability of the process.

Jan 1, 2000

The capacity of chlorine based solutions to rapidly and effectively dissolve coarse gold in oxide ores is well established. The inherent advantages of chlorine are high dissolution rates (10 - 100 times those of cyanide), and low cost. The high dissolution rates mean that coarse or poorly liberated gold may be dissolved over relatively short periods and hence ore particle size may cease to be such a critical factor. The cost of size reduction to allow adequate gold liberation in order to achieve an adequate gold recovery is less of a consideration when using chlorine than in traditional plant or heap leaching cyanide-based treatment systems.Because chlorine based solutions capable of dissolving gold evolve an unpleasant vapour phase with the potential for significant chlorine losses into the atmosphere, traditional heap leaching with active solutions being sprayed onto prepared heaps is not possible. The ore must be covered and the solution may be introduced beneath that cover through prepared injection `wells' and recovered through production 'wells'. The pit is flooded with active solution beneath an overburden or cover with the solution migrating from the injection 'wells' to the production 'wells' over a period of around five - ten days.

Jan 1, 1992

By Barber C, Buselli G

Detailed monitoring of point sources of groundwater pollution is expensive due to the high cost of drilling monitoring boreholes. Whether groundwater pollution is due to mining, industrial or domestic waste disposal, a universal difficulty when monitoring groundwater contamination is the placement of boreholes to adequately define the extent of the pollution plume. This paper reports groundwater 'resistivity variations determined from transient electromagnetic soundings at a domestic waste disposal site north of Perth in Western Australia. Together with available hydrogeological and water quality data, the geophysics provides a broad "plume scale" picture of groundwater contamination. A simple three dimensional model of plume development, which takes account of the dimensions of the wastes, has also been developed and shows good agreement with the spread of contamination indicated by the geophysics for relatively small values of the dispersivities. Better estimates of these parameters are still required. The work indicates that a combination of geophysics and modelling with ground-truth data from groundwater quality monitoring of boreholes is required to avoid difficulties in interpretation of data and to better define the extent and migration of pollution in Groundwater.

Jan 1, 1988

Throughout industry in Australia, time lost through work accidents and illness is three times greater than strikes. In 1978 in New South Wales alone, 400 workers died, 125,000 were injured, 6,000 were indust- rially deafened, and 3,800 people died of occupational cancer. It has been estimated that less than 10% of workers injured make claims for common law damages. The figure is probably in fact much lower than that. However, common law damages claims are starting to become a boom industry and employers are only now starting to see the effect of the increase in Claims. I predict that within 5 years the number of common law damages claims made will increase dramatically.

Jan 1, 1982

The Sydney Coalfield, Nova Scotia contains extensive undersea longwall mining operations which are expected to continue well into the 21st Century. A long term research program has been initiated by the Cape Breton Coal Research Laboratory to investigate the full spectrum of problems associated with undersea mining and develop specific guidelines for use by the mine operator. At present, research is centred on the detailed evaluation of existing undersea sub- sidence guidelines, the identification and development of instrumentation capable of moni- toring seafloor subsidence profiles and the effective sealing of offshore exploration boreholes. In addition, work is also planned to examine in situ strata permeability changes occurring between the mining horizon and seabed and the feasibility of using artificial islands.

Jan 1, 1986

Traditionally, surface coal mines in the Western United States have been limited by economics to depths between 150 to 200 feet. Utah International Inc., however, is now planning to strip coal its San Juan Mine in Northwestern New Mexico to depths ranging up to 400 feet while uncovering 20 feet of steam coal. This method is cost-competitive with nearby shallower coal deposits and underground mining of the same property. How trucks and shovels can pre-strip for a dragline, along with results of the planning process, comparison with alternate systems, capital requirements, operating costs and comparisons with other coal sources are all detailed. Also discussed are the major problems anticipated, how they might be corrected, and potential improvements to the concept. Introduction The San Juan Deep Stripping Project will be situated at Utah International's San Jean Mine. The mine is in the Four Corners region, so-called because four states enjoy a common border point about 30 miles to the northwest.(see Figure 1). The area is a semi-arid plateau region with an average elevation of 5,200 feet, receiving an average of 6 inches of precipitation annually

Jan 1, 1981

When a fire or explosion occurs underground the ventilation maybe disrupted and the atmos- phere may become oxygen deficient and filled with noxious and flammable gases. The basic survival technique for:any man alive underground is to escape and this may be achieved and rescue workers may enter such atmospheres to carry out rescue work underground by using appropriate breathing apparatus.

Jan 1, 1983

I began my interest in sample preparation when I joined the Institute of Nuclear Sciences in 1962. I worked in the fields of rock dating and stable isotope geochemistry. Preparing a sample could take several days and the analysis took another day or more, so great care was taken with each sample. In 1968 I changed to mineral exploration analysis and was surprised to find that there was much less care in how a sample was taken and prepared. Virtually every sample was processed in the same way. In the use of ring and puck mills, Australia and New Zealand were among the world leaders. It took another ten years before labs in North America changed over from disc mills. In 1975, my partner and I divided our business into two parts. He took the laboratory into his consulting laboratory business and I took the small business that we had started, making ring and puck mills. For the next six years I was RocklabsÆs only employee. In the 1980s and 1990s, sampling specialists like Francis Pitard and Dominique Francois-Bongarcon began to make a difference in the understanding of what constitutes good sampling and preparation practice. They and others took courses on the new concepts of Sampling Theory, as developed by Pierre Gy. The desire for better procedures lead to the development of new machines, including the big bowl pulverisers from Australia, jaw crushers that could crush finely like our Boyd Crusher, rotating dividers of new designs and flow-through ring and puck mills. Other machines did not fare so well, including rolls crushers, cone crushers and hammer mills.

Jan 1, 2008

By Denisov GA

Conventional processes for disintegration of ores are characterised by low selectivity and cause damage to the components of their structure. It affects their liberation and recovery which are connected also with the inevitable formation of extreme fines. In the world practice recently came into view 4 trend to grinding of materials within a thick layer (in a bed layer), which provides a substantial selectivity of liberation, for example, of kimberlite. The degree of diamond preservation in the final product is highly increased. However, this method causes a considerable overgrinding of material. A new method of intralayer vibro-impulse breaking of materials providing an easily adjusted force acting at the layer and timely removal of product size grains from the grinding chamber has been developed in Russia.

Jan 1, 1993

By T Galvin

Drilling and blasting at Westside Mine near Wallsend, NSW, has presented a challenge for Orica Explosives, Australia. The colliery produces 600 000 tonnes of steaming coal per year from two seams using surface mining techniques. Tapping into underlying coal will greatly improve the yield, but there are many issues which make this an enormous challenge. Hunter Valley Earthmoving engaged Orica Explosives to supply the explosives products and to provide much of the blasting expertise that is needed on the minesite. Hunter Valley Earthmoving and Orica Explosives have proven to be an outstanding, unified technical team on this project. The success of the team is based on good communication, progressive attitudes, extensive expertise in blast design and most importantly, care and accuracy in implementing the agreed upon designs.

Jan 1, 1999

The GDR has extensive lignite deposits at its disposal, which formed the basis for the development of an independent energy source after 1945 and which will retain their significance well beyond the year 2000 (see fig. 1). In 1946 lignite output was about 110 x 106 t. In 1985 312x 106 t was produced and in 1988 the planned output will be ca. 315 x 106 t. Thus, the domestic produc- tion of lignite covers ca. 75% of the GDR's primary energy requirements. More than 80% of the electrical energy is gener- ated by the use of lignite and about 12% by nuclear energy. In addition to this, about 18 x 106 t/a mineral oil and about 6 x 109, m3/a natural gas are imported, predominantly from the Soviet Union. The lignite deposits of the GDR are of Tertiary origin and are recovered exclusively by opencast mining. There are two large regions (fig. 2): - in the region east of the river Elbe (Cottbus/Senftenberg- "Niederlausitz") and - in the region west of the river Elbe (Halle/Leip- zig/Magdeburg). These deposits differ in geological age and conditions of depo- sition, consequently there are differences in their chemical and physical composition and, thus, in their uses. The younger Mio- cene coals of the main region in the East of the river Elbe belong to the epirogenetic type and have a low content of ash and sul- phur. Among other things, they are suitable for the production of brown coal high-temperature coke (Lauchhammer and Schwarze Pumpe). The older Oligocene coals of the Halle/Leip- zig region are bitumenous in certain areas. Therefore, they form the basis for production in low-temperature carbonizing and chemical plants. In the Halle-Magdeburg region, where the lig- nite is in contact with the underlying Zechstein subdivision, so- called "salt coals" are found.

Jan 1, 1989

By Swift D. G

For some time the Electricity Trust of South Australia (ETSA) has been investigating the application of new mining methods and equipment to minimise the cost impact of the steadily increasing depth of mining brought about by the 20¦ dip of the coal seams at the Leigh Creek Coalfield. Exhaustive examination of all suitable mining systems showed that highly mechanised systems involving belt conveyors displayed no eco- nomic or operational advantages over shovel and truck methods. However, the configuration of the Leigh Creek coalfield allows for two quite different approaches to mining by shovel and truck. The current strip mining method involves removing overburden from the highwall in 60 m to 200 m wide strips to progressively expose the coal down dip, and requires all waste to be hauled to the surface. The alternative ter- race haulback method involves opening a boxcut to full depth at one end of the coalfield, then mining the full section along strike and placing the spoil in the mined out area. On a strictly economic basis, the latter is clearly advantageous, but the former has significant less tangible advantages. In deciding between the two methods ETSA is faced with the need to examine the applicability of each method under a wide range of possible future demands on the coalfield, and to assess the importance of many intangible factors.

Jan 1, 1989

By Davies K. E

Several nuclear techniques have been assessed for application to online conveyor belt analysis of oil yield from Rundle oil shale. The most favourable technique is neutron inelastic scattering which determines the total carbon content of bulk shale samples. Correlations of chemical laboratory assays for 540 Rundle oil shale samples show that oil yield can be predicted from total carbon to within 11 litre/tonne.Laboratory experimental work on 17 bulk samples of Rundle oil shale indicated that carbon and oil yield can be determined to within 0.6 wt per cent and 9 litre/tonne, respectively, using the neutron inelastic scatter technique. A practical neutron inelastic scatter gauge for application on a 23 mm thick reinforced conveyor belt could consist of a 5 curie 241 Am-Be neutron source and a 150 mm diameter x 100 mm thick Nal(TI) detector. With this gauge, the analysis time to achieve a counting statistical error of 6 litre/tonne should be about five minutes.

Jan 1, 1985

A feasibility study will fail its objective if it does not identify and then correctly assess, all the risks which could have a substantial impact on the financial viability of a project. Before this assessment can be undertaken, one needs to understand the risk profile of the entity which is making the decision about the project. Some of the commonly encountered issues when assessing project risk are related to the problem of not being able to see the wood for the trees. In any risk analysis it is important that conservatism does not strangle a viable project; that the variables are internally consistent with each other, that reality checks are carried out and that appropriate expertise is used. Sensitivity analysis forms a part of the overall project risk assessment; however, it can only test those variables which have already been identified in the financial model. The most useful tool in performing a sensitivity analysis is Monte Carlo simulation. When properly used, it provides a more real world scenario than the simple adjustment of key variables by ¦ 10 per cent one at a time. Monte Carlo can provide valuable information about the robustness of a project. Project risk and sensitivity assessment is prone to the analysis paralysis syndrome. The focus should be on quality rather than quantity.

Jan 1, 1997

By Richmond GD

The Hellyer concentrator of Aberfoyle Limited commenced production in 1989 processing a fine grained, massive sulphide ore containing Zn, Pb, Ag, Cu and Au as values. Four concentrates are produced - copper/silver, lead, zinc and bulk (Pb/Zn) - with overall payable recoveries (1991) of 80 per cent Zn, 55 per cent Pb, 50 per cent Ag, 30 per cent Cu and ten per cent Au. Metallurgical development work commenced immediately after plant commissioning, and continues. The flotation response and liberation analysis on a size basis highlighted reagent balance problems associated with tower mill regrinding of sphalerite, poor conditioning of flotation pulps, poor selectivity for fine galena, and insufficient liberation. These were the main causes of values lost to tailings, values reporting to the 'wrong' concentrates and of impurities in the concentrates. Modifications to tower mill regrind circuit operation, and the use of improved conditioning techniques have greatly improved concentrator performance, particularly in the finer (-5 micron) size fractions. Studies of concentrator and laboratory flotation by size and liberation analysis are the basis of diagnostic metallurgy. The techniques used to evaluate the improved concentrator performance are discussed.

Jan 1, 1993

Previous studies on the blast furnace raceway zone have been undertaken at three levels of scale, namely: laboratory models at low temperature, hot models which simulate coke combustion in the zone, and tests performed on operating and dismantled blast furnaces. This paper reviews the results of this published work on raceways in order to illustrate the factors which affect the raceway shape, size and combustion characteristics. As a result of the work it has been established that raceways are influenced by blast parameters such as velocity, temperature and chemistry, as well

Jan 1, 1981

Magmatism and mineralization are features of the New England Orogen in late Palaeozoic- Mesozoic time. Voluminous silicic and mafic magmatism, both orogenic and post-orogenic in association, was accompanied by abundant mineralization in the earlier phases. Later activity passed transitionally into less vol- uminous felsic to mafic intraplate basaltic volcanism, with possible migratory hot spot activity through the flanking Oxley and Sydney Basins. Only minor mineralization took place at this stage. A new inerpretation links these magmatic and mineralizing events to a major thermal cycle. A New England hot spot(?) complex evolved in latest Carboniferous/early Permian time. Its activity was partly obscured by orogenic magmatism as Australia moved slowly over magma sources in the deep lithosphere. In Triassic time Australia's movement changed direction and faster drift over the waning hot spot complex produced multiple migratory intraplateòactivity. The volume of magma and hence abundance of ancillary mineralization was related to age of the hot spot, speed of the continental movement over thermal sources and extent of accompanying orogenic activity. The New Eng- land Orogen hot spot(?) possibly existed for 165 Ma, with mineralization changing over this Period.

Jan 1, 1987

By G K. Robinson

The existence of bias in samples taken by cross-stream sample cutters has been investigated using three-dimensional discrete element method (DEM) modelling. Detailed quantitative information on overall extraction ratios, size specific extraction ratios, missed and extra sample components can be made by comparing a reference sample to the actual sample. A key advantage of using this modelling approach over physical experimentation is that the reference sample can be measured on precisely the same portion of the stream of material as the actual sample, thereby allowing the elimination of a significant fraction of the variability and allowing statistically significant results to be obtained using many fewer replicates. Quantitative analysis of results broadly supports the commonly-used rule that the cutter aperture should be at least three times the nominal top-size of the material being sampled, but does not support the commonly-used rule requiring increase in cutter aperture if the cutter speed exceeds 0.6 m/s. Sampler performance can be understood in terms of the balance of forces in the congested region of material formed by the slowing of the particle stream due to collisional interactions around the mouth of the cutter.

Jan 1, 2008

By M Kongas, K Saloheimo

Concentrating lower and more variable grade ore resources to meet acceptable concentrate quality criteria requires removal of significant amount of gangue minerals. Monitoring plant feed mineralogy and concentrate by on-stream analysis has significant economic benefits in concentrate quality and recovery optimisation. There is a need to develop a sensitive slurry on-line analyser for silica, aluminium, magnesium and other light elements.On-line XRF elemental analysis technology, which is a routine practice in base metal concentrators is not able to measure lighter elements than calcium from slurry. Too much of the X-ray fluorescence signal from lighter elements is absorbed by water. The limitations in the direct measurement of silica and other light elements have restricted its use in some applications. Some light element slurry analysers have been developed based on prompt gamma neutron activation (PGNAA) method but they have not performed up to the expectations. This paper describes a new on-line elemental slurry analyser and the results of on-line laboratory tests.CITATION:Kongas, M and Saloheimo, K, 2013. Online light element slurry analysis, in Proceedings MetPlant 2013 , pp 93-101 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

Underground measurements, observations and computed simulations, started a long time ago were concerning the study of : - occurence of typical rockburst, - inducing, stretching of main fractures in the roof of caved longwalls. They made obvious a foundamental phenomenon of inducing of strata fractures involving contact be- tween two layers quite different in their elastic characteristics : coalseam and rocklayer.. The start of primary cracks in maximum abutment zone takes place in the rock near the contact surface. It is opening of crevasses induced by traction stress component resulting of difference of rigidity of both materials and no sliding on in- terface. Occurence and stretching of these crevas- ses are a rheological phenomenon so that the rate of advance and stops of the face influence the distance between the crevasses and the stretching of these ones. The characteristics of these cracks in space and time affect mining conditions. So it is for fractures proximity and expan- sion inducing eventual blocks formation in longwall roofs in front of faces, for depth and delay of road- ways ribsides fracturing, inducing some rockbursts. In longwalls roofs, cracks initiated in front of a face can be either quite close or quite distant each from the other one, according to the depth of crushed coal in front of the face, which af- fects also extension of the cracks.

Jan 1, 1988