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Technical Challenges in the Flotation of Molybdenite from Porphyry Copper Ores

Sep 13, 2010

Exploring the Breakage Environment in Mills with Discrete Element Methods

Sep 13, 2010

By G Mark, K L. Blake, G de Jong, J F. Rotherham, N D. Adshead

Magnetite deposits with distinctive ¦ actinolite ¦ apatite-bearing gangue and spatially-extensive sodic-calcic wall rock alteration occur in both Proterozoic metamorphic terrains and Mesozoic-Tertiary magmatic arcs. Examples from both settings constitute significant sources of iron ore (egKiruna, Sweden; El Romeral, Chile) and some host major Cu-Au deposits that have a local association with K-silicate alteration (eg Cloncurry district, NW Queensland; Copiapo district, Chile). A growing body of evidence points to a hydrothermal origin for these systems involving high temperature, low S oxidised fluids. The Cloncurry magnetite-Cu-Au deposits are products of the local structurally channelised influx of a specialised high salinity ore fluid into larger-scale alteration systems developed during pluton emplacement at greater depths than those associated with subvolcanic (porphyry) Cu-Au deposits. The geological characteristics of deposits in magmatic arcs are consistent with a similar mode of origin albeit in rather different tectonic settings.

Jan 1, 1995

Principles of management in ore preparation before process of enrichment of chrysotile ores are discussed. The formulas, which were tested in industrial conditions, are offered, which may be used for averaging of chrysotile-asbestos fibres by content in ore and grade.

Dec 6, 2010

Prefeasibility planning and cost estimation of conveyor systems has historically been undertaken by comparing fixed plant transport requirements to that of similar systems in service. This paper describes the development of a prefeasibility conveyor technical design and cost estimation application using Microsoft Excel Visual Basic for Applications (VBA) platform. The application tool known as D-Convey (Dachshund Convey) was developed with the goal enabling the end user:- to develop a technical model for conceptualised conveyor systems,- to perform economic analysis on the developed technical model, and - to conduct a comparative and risk analysis.An Excel VBA based platform was utilised to draw upon both the analytical and graphical capabilities of a spreadsheet. Some of the features of D-Convey system include a revolutionary dynamic graphical help system, known as the 'information pane' in lieu of traditional help files as well as the use of familiar graphical user interface elements such as the MS Office 2007 task ribbon. The D-Convey system incorporates material database allowing for mass handling prefeasibility estimation in other industries; it has been validated at a local quarry.

Dec 6, 2010

Ore sorting is a high capacity, low cost method of pre concentrating ores and in some cases of producing a marketable concentrate. In most cases it is applied to run of mine material, immediately after primary crushing and screening in sizes ranging from 10 mm to 150 mm. Recent developments in bulk sorting of friable uranium deposits have resulted in machines capable of handling fine materials with sensing and separation being achieved on a zone by zone basis. Modern ore sorting machines rely on the synchronous operation of four internal subsystems, feed presentation, sensing, data processing and separation. A variety of different sub systems is available which can be combined in various forms to produce sorters capable of handling a wide variety of mineral types. The benefits in using ore sorting cover a wide range of situations and are applicable to both established mines as well as new mining ventures. Reduced operating costs, increased productivity, capital savings, energy and resource conservation and environmental issues are all part of the reason why ore sorting is finding rapid acceptance in today's mining industry. The suitability of different ore types for pre-concentration using anyone of the variety of ore sorting systems can be quickly established using computer based techniques which require only small samples of the materials under investigation.

Jan 1, 1980

By M Carter

The Great South Basin is located beneath the northwest part of the Campbell Plateau, a+broad, nearly level, triangular shaped submarine platform, southeast of the South Island of New Zealand. It encompasses an area of 77 700 square kilometres and contains a sequence of Cretaceous to Tertiary sedimentary rocks which are up to 6000 metres thick near the centre of the basin (Shirley, 1983). The western boundary of the basin is adjacent to the steep Aucklands Slope. In the+ north it merges with the Canterbury Basin and to the south onlaps against the Pukaki Rise, a basement high. The eastern margin of the basin is bounded by the northeast - southwest trending steep linear Antipodes Scarp. In the extreme south the Antipodes Scarp curves westward and joins the north trending Aucklands Slope. The Campbell Plateau is dominated by tensional tectonics. The Antipodes Scarp represents a major region of transcurrent faulting initiated by Cretaceous rotation within the Campbell Plateau. Later movements are associated with the Alpine Fault of the South Island (Sandford, 1980; Anderton, Holloway, Engstrom, Ahmad and Chong, 1982).

Jan 1, 1983

By Waugh D. M

investigations have been undertaken into the flow characteristics of mineral slurries from a number of Australian metallurgical plants including Mount Isa Mines Ltd., North Broken Hill Ltd., and Broken Hill South Ltd. Experimental equipment installed for this work included facilities for continuous recording of flow rate and pressure drop and detection of sedimentation.Although the method has subsequently been described in published literature, it is believed that the investigations included the original application of a method for correlation of the flow rate and pressure drop data. This method depends on solving by graphical methods the values of the constants k, and c in the relationship EQUATION 1 where D is pipe diameter; ?P, pressure drop; L, length; and V, mean linear velocity. Discussion of this correlation also reveals why sedimentation velocity does not necessarily vary greatly with pipe diameter.INTRODUCTIONIn order to design pumps and pipeline installations for a Newtonian fluid, measurements of the fluid's density and viscosity in any of a number of instruments are sufficient. Substitution of these values in well known equations to calculate Reynolds numbers and subsequent correlation to determine friction factors are all that is required for engineering specification.As a result of work during the last decade, particularly that of Metzner and Reed (1955) and Dodge and Metzner (1959), it is now possible to design for homogeneous non-Newtonian fluids using relatively simple instrumental measurements.These methods can sometimes be applied to thick slurries which behave as if homogeneous. However, for the...

Jan 1, 1965

By R Lethlean

The mining industry in its drive to optimise equipment use and minimise cost simply to remain profitable in an uncertain commodity market needs to develop a greater understanding of equipment capabilities and cost. The factors influencing mobile equipment fleet cost and performance commence at the time of mine planning and continue to exert an influence over the life of the mine. These factors must be understood at the early stages of any operationÆs planning process as they continue to impact both positively and negatively on fleet performance and operating cost throughout the life of the mine. The key factors examined in this paper include: grades; rolling resistance; fragmentation and truck loading.

Jan 1, 1998

Upgrading of Superfine Low-Grade Haematite Ores by Reverse Floatation Direct Reduction Low Intensity Magnetic Separation Process

Sep 13, 2010

This paper gives a description of the methods of mining employed at North Broken Hill Limited, Broken Hill, N.S.W.GEOLOGICAL NOTESThe main Broken Hill lode occurs as a replacement of tightly folded pre-Cambrian sediments. Replacement has followed certain stratigraphical horizons and the main bulk of the ore is found where these have been packed into the noses of anticlinal and synclinal folds.Throughout the mine the ore-bearing folds pitch north fairly consistently at 45 degrees, as a result of which two favourable horizons in the same fold appear in plan as separate orebodies and these are referred to as the "Southern Orebody" and the "Northern Orebody" respectively.The general dip of the orebodies to the west is about 60 degrees. A typical sill is shown in the plan of the 1,400-ft level (Fig. 1).Both the hanging wall and footwall rocks throughout the mine are weak and, as a result, it is necessary that the hanging wall must be well supported after ore extraction, to prevent subsidence. The weakness in the footwall is confined to a narrow zone, approximately 60 feet in width. This weaknes.q is a source of trouble in the development headings which pass through it, It is sufficiently crushed to transmit weight from the overlying wall to the gangways below.Another feature causing ground instability is the presence of many faults. Although their effect on the shape and character of the orebody is relatively small their...

Jan 1, 1940

By L S. Shekhawat, M P. Roy, R K. Paswan, P K. Singh, A Joshi

Blasting in the mining industry is being transformed, and can no longer be treated as an art or a practice purely dependent upon experiences of individuals. Examples of key drivers that have demanded consistent and more accurate blast results are initiatives to control pit-wall damage to help mine steeper pit slope angles, to control damage to underground opening operating in close vicinity of the open pit mine. Such situation exists at Rampura Agucha open pit lead zinc mine, which is producing 5.7 Mt/a of ore and has started its underground part, which is slated to produce initially 2–2.4 Mt/a and 4.5 Mt/a in the near future. The open pit mine is currently working at 326 m depth and is designed to reach 421 m deep. It has been planned to operate the underground mine maintaining 50 m parting from the planned ultimate level of the open pit mine.Presently, open pit and underground mines are being operated simultaneously. The present average depth of underground working lies between 370 and 410 m below the surface level. Sometimes explosives up to 95 978 kg are being detonated in a blast round in open pit mine. These blasts are often apprehended as a danger to the safety and stability of underground openings. It was decided to document the impact of open pit blasting in the openings of underground workings, so that preventive measures may be taken for the safety and long-term stability of the underground mine. The impact of 86 open pit blasts has been documented in the underground openings and 258 blast vibration data has been recorded. The vibrations were recorded simultaneously in the roof, side walls and at floor levels. The highest levels of vibrations were recorded in the roof and the lowest levels at the corresponding floor levels. The pillars experienced lower level of vibrations than the roof. Blast designs were optimised at open pit mine to control vibration in view of long-term safety and stability of the underground openings. The vibrations generated due to detonation of explosives with shock tubes and electronic delay detonators have been recorded in underground openings for comparative assessment. Ground vibration recorded at roof, pillar and floor were analysed separately and threshold value of the vibration for the safety of underground workings has been determined based on the rock mass rating of the roof rock.CITATION:Singh, P K, Roy, M P, Paswan, R K, Shekhawat, L S and Joshi, A, 2015. Protection of underground mine structures due to adjoining open pit mine blasting, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 279–288 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

Improving Pentlandite Selectivity Over Pyrrhotite Using Reagents

Sep 13, 2010

Assessment of the Consistency Between Different Laboratory Froth Stability Measurements

Sep 13, 2010

By K Thorpe

Amorphous silica deposits have been identified at Tikitere and Taheke near Rotorua. Two areas at Tikitere have been surface sampled and drilled to establish a resource of amorphous silica in excess of one million tonnes. A pilot plant was established to develop a process to manufacture a high quality super pozzolanic material. This development process took two years before a commercial product was introduced to the construction industry in 1996. The amorphous silica product, marketed as Microsilica 600, is used as a pozzolanic material to produce high quality strong and durable concrete, sprayed tunnel linings, mortars and grouts. Microsilica 600 has been used locally and exported to 11 countries.

Jan 1, 1999

A survey has been undertaken of the petrography of North Island greywackes with a particular focus on the occurrence in them of smectite (swelling clay) and chlorite, two minerals that are closely associated, chemically similar, and commonly interlayered with each other. Smectite is the mineral which is a major cause of greywacke aggregatesÆ poor performance. Smectite occurs in post-metamorphic shear zones and in surface weathering profiles over greywackes. This study focuses on the petrography of fresh greywacke rocks.   The occurrence and abundance of smectite and chlorite and their relationship in greywackes is largely a function of the chemistry of the sediment and the maximum temperature that the sediment has been subjected to during diagenesis and/or very low grade (anchizone) metamorphism. Rock chemistry, particularly total iron and MgO, determines the smectite and/or chlorite content in fine-grained greywackes (argillites and siltstones) but chemistry is less influential in sandstones, where at low grades of metamorphism much of the Fe and Mg of the rock is held in unreacted detrital minerals and the mineral constituents of lithic grains.   Four zones which represent different levels of diagenesis and very low grade metamorphism, based on the crystallinity of illite and chlorite in the greywackes, and the proportion of smectite interlayered with chlorite, have been mapped in the North Island. In the anchizone smectite does not appear as a discrete mineral, it is always interlayered with chlorite. In the upper anchizone chlorite contains approximately ten per cent of smectite interlayered with chlorite. In the lower anchizone about 30 per cent smectite can occur in chlorite.   In addition to the smectite and chlorite inherent in the greywackes as the result of the thermal overprint, smectite as a discrete mineral and smectite-chlorite interlayered minerals with high levels of smectite, occur in abundance on shear zone surfaces and in alteration zones adjacent to shear zones; these are the main contributers to the high levels of smectite recorded in many greywacke aggregates.

Jan 1, 2006

This paper describes the past, normal and advanced practice of optimisation in mining. It then discusses what needs to happen for the mining industry to make full use of what is now available.

Dec 6, 2010

Study on Mineral Processing for a Cassiterite Ore in Southwest China

Sep 13, 2010

Media Type Effect on Grinding Efficiency

Sep 13, 2010

Present roof bolting practices in the collieries of Australian Iron and Steel Pty. Ltd. are outlined. Roof support has been improved since introducing roof bolts and it is hoped to increase the reliability of the bolts still further.Expansion-shell, and split and wedge roof bolts five to eight feet long are placed by "Atlas Falcon" and "Fletcher" roof bolters. Both anchorage and tightening have presented some problems.Good panel supervision is required if systematic roof bolting is to be properly co-ordinated with coal production without unnecessary delay to either. Successful roof bolting can only be the product of conscientious men and supervisors who are all convinced of its value. A rigid operational code should be established early and maintained.INTRODUCTIONRoof bolting is a method of support which is permanent and reduces or eliminates the need for other support; The method was pioneered in America and was first experimentally investigated in Australian collieries at Elrington in 1949 (McKensey, 1953). Pneumatic installation methods were employed. Subsequently, a method of using standard hand-held electric coal drills was developed at John Darling Colliery (Horseman, 1954). Pneumatic roof bolting equipment was first operated in the collieries of Australian Ironand Steel Pty. Ltd (A.I. &. S.) in 1951. Since then various hydraulically operated mobile machines have been installed in Australian collieries and these, together with improved pneumatic equipment, form the two present basic methods of placing ,roof bolts. Roof bolt anchorage is achieved by either split and wedge or expansion-shell bolts.The two broad types of roof bolting are 1. consolidation of strata, and 2. suspension support.

Jan 1, 1961