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By P Holtham, K C. Runge, E Tabosa

Traditionally, comminution and flotation have been surveyed, analysed and optimised separately. This often results in less than optimal outcomes because of the complex interactions between the two processes. Flotation recovery is a strong function of the valuable mineral particle size distribution with lower recovery of ultra-fines due to poor flotation kinetics, optimum recovery for the intermediate sized particles and lower recovery for the coarser particles due to poorer liberation. Thus, to optimise flotation recovery and grade it is usually best to grind to a fine size. This requirement needs to be balanced by the cost of grinding finer and the revenue that results from an increase in grinding throughput, which often results in a coarsening of the flotation feed.This paper demonstrates a technique which can be used to predict the effect of a change in feed grind size on flotation performance. It can be used to determine the optimum grind size for a particular operation which optimises total circuit profitability. Analysis is relatively easy to perform, as a minimum, requiring only size by assay data of the feed and product streams of the process. Case studies will be presented that demonstrate the usefulness of this technique in feed grind applications. Potential use of the technique for regrind evaluation is discussed. The limitations associated with this technique in certain circuit scenarios will also be outlined.CITATION:Runge, K C, Tabosa, E and Holtham, P, 2014. Integrated optimisation of grinding and flotation circuits, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 77–84 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By Nicol SK, Engel MD

Ion flotation involves the adsorption of ionic species, in association with surfactant molecules, at the surface of rising gas bubbles, for the purpose of recovering and concentrating those ions. The objective of this study was to optimise the ion flotation process using a heap-leach liquor, containing gold cyanide, and the surfactant cetyl trimethyl ammonium bromide (CTAB). The aim was to minimise the surfactant reagent dose, maximise the throughput of feed liquor in the process, and satisfy the dual constraints of a high gold recovery and a high volume reduction factor. Development of a first order model of the ion flotation process formed the theoretical basis for the test program procedure and the interpretation of the results. Batch tests were used in order to determine the ultimate recovery curve for the heap leach liquor-CTAB surfactant system. The results indicated that a surfactant dose of about 0.083 g/l would be necessary in order to achieve a satisfactory gold recovery. Continuous tests were then performed on a small-scale pilot plant at the Newcastle Laboratories. The optimum result achieved was a gold recovery of 85 per cent, a volume reduction factor of ten, and a feed throughput of 2.3 m3/m2-h. Recent work also indicates that very much higher volume reductions can be achieved using a larger diameter vessel. The improvement may be a consequence of a reduction in wall effects and hence an improvement in foam drainage.

Jan 1, 1993

By Szymanski J

In the first part of this paper, the principal sources of dilution during underground evaluation and mining are discussed, then definitions of ore dilution currently in use are analysed. These definitions vary depending on the authors. Ten different analytical expressions of dilution percentage currently exist. It is demonstrated, with the help of a numerical example for a given mining condition, that dilution percentage results vary considerably and that they depend on the definition used. This situation makes it difficult to compare different results regarding the dilution problem, often because some of the terms used are contradictory. A new ore dilution evaluation methodology is proposed, replacing the ten different analytical expressions by only two: the planned dilution factor related to the stoping selectivity, done at the mine planning level, and the additional dilution factor related to the efficiency of the dilution control measures during stoping operations. The conclusion shows that the use of this methodology would be a definitive asset in planning, in stoping operations follow-up, and in future costs comparison studies between mining operations.

Jan 1, 1995

By Hagan T. N

Quite apart from economic considerations, the following performance parameters must be considered when selecting an explosive for a particular blasting operation. 1. total energy yield/kg, and more particularly, strain energy/kg and bubble energy/kg of charge 2. charge weight/m of blasthole 3. sensitivity of the charge 4. water resistance of the charge The effective division of an explosive's total energy into strain energy (SE) and bubble energy (BE) is explained as is the influence of each energy component on blast results. Because some rocks require a high strain energy for effective breakage, while others are most satisfactorily fragmented by bubble energy, values of SE and BE are more meaningful than those of total energy. Unfortunately, our extensive knowledge of the effects of certain variables on total energy has not yet been completely supplanted by the influence of these variables on SE and BE values. Relative SE/kg and BE/kg values are presented for a range of explosives. The 'charge density of ammonium nitrate/ fuel oil (ANFO)-type explosives is essentially constant throughout the length of the charge; because of their compressibility, slurry

Jan 1, 1974

The completion of the Hot Strip Mill at the Port Kembla works of Australian Iron & Steel Ltd., makes possible the production of steel plates and wide strip of a quality and in quantities not possible previously in Australia, and will also enable the production of tinplate to be undertaken in this country.The site chosen for the mill was a mud fiat underlain by a hard stone bottom at 5, to 801 feet below the surface; and a total area of one hundred acres was reclaimed to a level of 20 feet above the original surface.Three adjoining buildings were constructed to house the slab receiving yard, mill equipment and electric drive, together with the plate finishing line.After slabs have been heated to 2250°F at a rate of 90 tons per hour, they are transferred to the vertical scale breaker which is the first stand in the hot roughing mill. Here the primary furnace scale is first cracked and then blasted off by high velocity water descaling sprays.The next stand is the horizontal scale l;Jreaker, where any remaining primary scale is broken and then blasted off. After descaling, the slabs pass to the broadside mill, where short slabs are turned and rolled on broad side for wide plate.The next step is a slab squeezer which squares up the edges after broadsiding ready for the reversing mill. This is the finishing stand for plate and the last roughing stand for strip, which then passes to the finishing mill.The hot strip finishing mill consists of six stands with a maximum finishing speed of 2,230 feet per minute. Strip is cooled for coiling by water sprays on a hot run table and then coiled on a mandrel type downcoiler, from whence coils of hot strip are weighed and transferred by conveyor to the coil storage building.Plates are transferred from the reversing mill to the plate finishing line where operations consist of levelling, inspection, branding, cutting to width and length:INTRODUCTIONDue'to the increasing production of cars, refrigerators, washing machines and similar consumer goods in Australia, together with the increased requirements of galvanised iron...

Jan 1, 1956

By Doyle P, Mulroney D

The Cassidy Shaft was sunk to access the Mount Charlotte and Reward Orebodies below the Flanagan Fault. The 1,184m deep shaft is concrete lined to 6.5m diameter for its full depth. The initial 590m was excavated by stripping into a 1.8m diameter borehole and hoisting the broken material through the existing mine. The remaining 594m was excavated by conventional shaft sinking methods. The shaft was sunk through 3 existing plats and an additional 8 plats cut. 1,800 tonnes of steel and 8 cables were installed during the furnishing of the 4 compartments.

Jan 1, 1985

By Murray C. G

A database of over 1300 earthquakes has been used to investigate the relationship between seismicity and tectonics in two areas of eastern Queensland and NE New South Wales. These areas have been monitored by several networks that were installed primarily to monitor seismicity associated with the impounding of large reservoirs. Events that occurred prior to the installation of these networks have been excluded from the analysis because they have large uncertainties in location.Seismicity in SE Queensland and NE New South Wales is concentrated in the coastal regions. Activity also extends off the coast of Queensland and beyond the continental shelf. The coastal activity is mainly within the New England Fold Belt. An area of the fold belt overlain by the Clarence-Moreton Basin is also active. There is an area of activity near St. George that correlates to the Wunger Ridge. Fraser Island and the adjacent onshore area, near Maryborough, are notably aseismic.Within the New England Fold Belt there is a NNW trending zone of concentrated activity that includes the South D'Aguilar Block and the Esk Trough as far as Gayndah. The Nambour Basin, the Gympie Province, and the southern portion of the Yarrol Block are significantly less active.Composite focal mechanisms of several groups of accurately located earthquakes in SE Queensland indicate predominantly reverse faulting. This faulting is the result of the crust being compressed horizontally in a NE-SW direction.Activity in the Burdekin Falls Dam area of central eastern Queensland is confined to the Drummond and Bowen Basins. There is also significant activity offshore from Townsville and Bowen.

Jan 1, 1990

By R L. Brathwaite

The rocks of New Zealand can be grouped into three main elements: the Early to Mid Paleozoic Western Province, Late Paleozoic to Early Cretaceous Eastern Province, and several overlying Late Cretaceous to Cenozoic sedimentary basins. The Western and Eastern provinces were formed on or near the margin of Gondwanaland, whereas the Late Cretaceous to Cenozoic sedimentary basins developed after the separation of New Zealand from Gondwanaland in the Late Cretaceous.   The Early to Mid Paleozoic Western Province rocks are exposed in Nelson, Westland and Fiordland and include metamorphosed sandstone, mudstone, limestone, and volcanic rocks, intruded by granite batholiths and maficultramafic igneous complexes. The main associated mineral deposits are gold-quartz lodes hosted by Paleozoic greywacke and argillite. Other type of deposits present include: volcanogenic massive sulphide lead-zinc; vein and greisen tungsten and tin; and magmatic nickel-copper sulphide, platinum group element, and magnetiteilmenite deposits. Granite stocks and batholiths, intruded during the Cretaceous, have associated porphyry molybdenum deposits.   The Late Paleozoic to Early Cretaceous Eastern Province includes the greywacke rocks forming the axial ranges of the North and South islands, and a belt of schists in Marlborough, the Southern Alps and Otago. The schists host many shear-zone related, gold-quartz lodes and, in the Southern Alps, lenses of serpentinite with talcmagnesite and nephrite jade. Volcanogenic massive sulphide copper deposits and volcanogenic manganesechert deposits, occur in both the schist and greywacke, and a belt of Permian age ultramafic rocks (Dun Mountain Ophiolite) has associated copper, chromite and chrysotile asbestos deposits.   The Late Cretaceous to Cenozoic rocks are found in a number of sedimentary basins onshore and offshore of the North and South Islands. Many of these basins developed during the rifting of New Zealand from Gondwanaland in the Late Cretaceous. They contain New Zealand's economic petroleum, coal and limestone deposits. Uplift and erosion of the mountain ranges shed gold into rich placer deposits in the South Island.   From the Miocene, volcanic rocks feature prominently on the eastern South Island (e.g. Banks Peninsula southeast of Christchurch and the Otago Peninsula northeast of Dunedin) and northern North Island (Northland and Hauraki), and volcanism continues today in the Taupo Volcanic Zone. The North Island volcanic rocks have associated epithermal mineralisation, mainly gold and silver, but also copper, lead, zinc, mercury, and antimony, as well as deposits of sulphur, perlite, pumice and zeolite. Porphyry copper style mineralisation is associated with subvolcanic intrusive rocks. Erosion of the volcanic rocks has shed titanomagnetite onto the west coast of the North Island forming significant coastal placer deposits. Similarly, erosion of the Alpine schists in the South Island has resulted in placer ilmenite deposits on the coast of Westland.

Jan 1, 1997

By Muller GP, van Deventer JSJ

A mineralogical analysis has shown that in the Hartebeesfontein ore studied, uranium is associated mainly with uraninite, sulphides such as pyrite and to a lesser degree carbonaceous material such as thucolite. Little could be learned from the literature regarding the mechanism of flotation of these uranium-bearing minerals. A wide variety of reagents were used so that conditions enhancing the flotation of either the sulphides, carbonaceous material, oxides like uraninite, or combinations thereof, were created. As could be expected, the xanthate based floats gave-better selective recovery of sulphides than oleic acid. A substantial fraction of the uranium is associated with pyrite, so that addition of oleic acid to a xanthate float did not enhance the recovery or grade of uranium. After a pre-leach with sulphuric acid in which the pH and Eh were controlled so as to destroy the uraninite, higher uranium recoveries were obtained for the combined float (xanthate, DTP and oleic) and the DTP float. This was most evident when iron was added before flotation. Roasting, which destroyed the sulphides and thucolite, caused a significant decrease in uranium recoveries. The uranium liberated in this way was obviously not flotable in the same way as the uranium liberated from uraninite. A small amount of iron (2 kg/t) added before milling resulted in slightly higher grades and recoveries of sulphur for xanthate based floats. Higher iron additions had a detrimental effect on sulphur recoveries. Even in the case of oleic acid the addition of small amounts of iron had a positive effect on the recovery of sulphur and uranium.

Jan 1, 1993

By Dutton D

In the British coal mining industry, during the last decade, a great deal of environmental monitoring experience was acquired, particularly in the Doncaster Area of the Yorkshire coal- field, which had a long history of spontaneous combustion and gas emission problems. This paper summarises the experience obtained and shows how the introduction and operation of these systems has resulted in improved techniqu- es for fire detection and control. Some of these systems are described in detail with emphasis placed on the uses to which output data are put, and their impact upon management at colliery level. Reference is also made to the problems encountered in the development of such systems and how they were solved. The paper also makes reference to the recent Research and Development work of the NCB's Scientific Department and Mining Res- earch Development Establishment (MRDE), which was directed to the design and application of a range of underground sensors, and so ensured continuing progress in this field. The paper refers briefly to a new comprehensive monitoring unit and an integrated fire detection and data transmitting system which are currently being assessed in the Yorkshire coalfield.

Jan 1, 1983

The Imperial Smelting Process (ISP) for the simultaneous smelting of zinc and lead was developed at Avonmouth from the 1930's with activity intensifying in the late 1940's/early 1950's. Present operations are based around the No.4 furnace which was built in 1967. Development during the 1980's has been driven by the need to sustain operations at low metals prices and has been aimed at reducing manning whilst increasing output. Although hit by several major plant disruptions, progress has been steady, culminating in a ú10 million capital programme in 1988?89 to upgrade the operation. The most important technical developments, reflecting the needs of the 1990's have, in the sintering area, included improvements to feed conditioning and sinter quality, a 20% uprate in production capacity by debottlenecking, and pilot work leading to the installation of a Boliden-Norzink mercury removal plant. In the smelting area the ISP furnace has been rebuilt, with a redesigned bottom section to eliminate earlier operating sensitivities, and to achieve higher blowing capability, and at the zinc refinery the columns have been rearranged for more flexible operation and higher capacity.

Jan 1, 1989

A Feasibility Study to determine the future of ZC Mines was completed in mid 1987. Early in this study, which lasted two years, it was identified that significant reductions in treatment costs would result if the Zinc Corporation Concentrator was closed. All of the production from the existing two mines, The Zinc Corporation Limited (ZC) and New Broken Hill Consolidated Limited (NBHC), would then be treated in the concentrator at NBHC.After a partial upgrade of the NBHC concentrator, the ZC concentrator was finally closed and all of the equipment disposed of. This closure highlighted the need to concentrate all ore haulage in one shaft to further reduce operating costs and remove the cost of surface transport of ZC production to the improved NBHC concentrator. This paper outlines the changes that were made to improve the haulage system for ZC Mines. After a number of options were investigated, it was finally decided that the upgrade of the existing NBHC haulage shaft was the best option even though some production would be lost while the upgrade was in progress.

Jan 1, 1988

In 1985 BMR assessed Australia's economic demonstrated resources of mineral sands as follows: rutile 8.0 Mt, ilmenite 41.4 Mt, zircon 11.5 Mt, and monazite 229 000 tonnes. These resources are located along the east coast of Australia, in the southwest corner of Western Australia, and in the Eneabba region, north of Perth, WA. However, over 40% of Australia's rutile and zircon resources, particularly those on the east coast, are presently not available for mining because of environmental considerations. As well, east coast ilmenite has been considered unsuitable for use by sulphate route pigment producers because of its relatively high chrome content. World demonstrated resources of rutile and zircon are estimated by BMR as 29 Mt and 38 Mt respectively. Demonstrated resources of ilmenite amount to about 1 billion tonnes. These occur predominantly in hard rock deposits in Norway, Canada, USSR and China, as well as alluvial deposits in Australia, South Africa and India. Quantitative data for world monazite resources is sparse. However, world production of rare earth oxides is now mainly from bastnaesite, a hard rock resource. Australia is presently the world's principal producer of rutile and zircon, and also provides a major share of the world's ilmenite. With the expected increase in Australia's rate of output of these commodities, combined with restrictions on mining along parts of the east coast, its position could diminish substantially over the next 25 years.

Jan 1, 1986

By F C. D Michelin

Blast fumes are a significant health risk to underground workers, containing several dangerous gases such as carbon monoxide (CO), nitrogen oxides (NOx) and ammonia. To ensure safe working conditions, workers are not normally allowed to re-enter a mine until the gases are cleared. To predict if gases can be cleared efficiently, simulations can be performed to estimate the gas levels following a blast. For accurate modelling, a calibrated airflow simulation is required in addition to blast-specific parameters such as the yield rate (representing the amount of gas released per kg of explosive) and the dispersion factor (representing how quickly the gases can enter the air stream from the explosive site). Those parameters are not easily determined, as they will vary from blast to blast. Many post-blast gas recordings on mine sites were studied and the correct parameters were determined to ensure an accurate gas simulation. The variability of the results was then analysed and correlation to known parameters is suggested. Finally, recommendations on how to determine the correct parameter are presented.

Oct 12, 2022

By Knight J. L, Baker G

The Wonthaggi coalfield is in South Gippsland, about 90 miles southeast of Melbourne. It is situated on the down-faulted block of the South Gippsland highlands that lies south of the Kongwak fault, between the Powlett River and the sea (Fig. 1). The coal, which is of Jurassic age, occurs in two small, and intensely faulted, limnic basins, that lie on either side of a concealed ridge of Silurian sediments. The coal was first found as thin seams outc1'opping in the cliffs at Cape Paterson, but the seams that are worked at Wonthaggi are concealed beneath a veneer of Cainozoic sands that covers the Jurassic strata, and were found by boring.The c9al seams are worked by the State Coal Mine, which was opened in 1909 to ensure a supply of coal for the Victorian railways, following a prolonged strike in the Newcastle field of New South Wales. The total production from 1910 to June, 1943, amounts to 13,918,800 long tons of coal. The coal seams are faulted to a degree unknown in most coal...

Jan 1, 1944

The investigations described in this paper aim at the development of a new impact mill. The objective is to produce particle size distributions below 10 .tm without using an air classifier. Circumferential rotor speeds of up to 200 m/s are strived for.

Jan 1, 1993

By Aziz N

The objective of the paper is to develop an understanding of the influence of caving on powered support rating by examining the geology and support performance at two sites which represent the current extremes in support rating, ie 6/240 Ton supports operating in the Hirst Seam at Solsgirth Colliery, Scotland, and 4/900 Tonne supports operating in the Bulli Seam, West Cliff Colliery, Australia. A conceptual model is introduced which considers the coal ahead of the face, the powered support, and the caved waste to be three yielding foundations which interact to control the subsidence of the roof strata. Different caving mechanisms are identified for the strata of the Hirst and Bulli Seams, ihese mechanisms being related to rock properties, ie to the palaeogeography and depositional conditions at each site, producing caved wastes with different yield characteristics. The results obtained for convergence and support reaction during production cycles at both sites are analysed to show the manner in which support reaction is developed, indicating the importance of high setting load densities in the Bulli Seam. Evaluation of the work done on the subsiding roof strata during typical production cycles by two of the yielding foundations, ie the powered support and the caved waste immediately behind the powered support, is used to further demonstrate the influence of caving mechanisms on support rating.

Jan 1, 1986

By Barnes R. G, Agostini A, Lewis P. C

The Mineral Resources Audit is a five-year Program established to produce a comprehensive and objective assessment of the mineral resources of New South Wales, including prospective resources. The goals of the Program are to improve planning and land use decision-making; attract exploration and minerals related investment; help the Department to identify and fill gaps in knowledge; and develop methods to identify and quantify resource potential and prospectivity. To achieve the goals of the Audit it is necessary to assemble and enhance a large amount of information and it is necessary to spatially analyse this information using computer-based Geographic Information Systems (GIS) which allow the collection, storage, transformation and display of large quantities of spatial data. An extensive range of both map-based and textual data can be employed in spatial analysis and resources and geoscience modelling. In order to use this information, data sets have to be corrected and standardised. Many data sets need to be classified. An objective of the Audit Program is the spatial analysis of the State, region-by-region, and the release of cleaned-up multiple digital data sets as packages which include upgraded mineral deposit information, 'seamless' geological map layers showing lithology, structures and stratigraphy, and processed and classified geophysical map layers. These regional packages are important reference sets for the mineral resources industry and will assist delineation of regional exploration targets.

Jan 1, 1995

By May P. M

The role of chemical speciation in alkaline cyanide solutions is discussed by reference to recent experimental data from the authors' laboratories. It is shown that serious gaps exist in our present knowledge of the thermodynamics of cyanide complexes in solution. Nevertheless, using the available data and the JESS suite of computer programs it has been possible to develop a simplified chemical speciation model for alkaline cyanide solutions under conditions relevant to the gold extraction process. Some possible implications of the model for plant operations are Discussed.

Jan 1, 1991

By D Capstick, M B. Ebell

This paper describes the test work, process design, commissioning and operation of a processing system at the Ergo gold operation that improves the extraction efficiency from gold tailings material. The improvement in recovery is derived from the separation of the gold contained within the sulfides of the tailings material and a dedicated process stream to recover that gold.The sulfides are separated by means of a flotation circuit and that resulting concentrate is subjected to a regrind of below 20 ¦m to enable a greater liberation of the gold. The ultra-fine material is then subjected to a dedicated leach circuit to recover the now exposed gold particles.The case study is an example of the challenges of introducing new technology and methodologies to a well-established operation and thereby attaining improved efficiencies and tangible business benefits.CITATION:Ebell, M B and Capstick, D, 2013. Improving extraction efficiency from Witwatersrand gold tailings using flotation and ultra-fine grinding of concentrates, in Proceedings World Gold 2013 , pp 301-306 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013