Search Documents

By R H. Eric

Surface wave formation induced by a high-strength submerged jet in a bottom blown metallurgical vessels has been studied experimentally by using one-seventh water model of CLU (Creusot-Loire Uddeholm) reactor with two different tuyere configurations. Experimental results have been discussed in terms of the wave period, wave frequency and wave amplitude with respect to air injection rate and tuyere configuration at a 0.23 m bath height. The results from high speed photography observations displayed the formation of rotating surface waves which circulates within the water model. It was found that the frequency and the amplitude increased with gas injection rate. The wave period for off-centre nozzle orientation was found to be lower than those of the centre configuration. The experimental results also showed that the frequency of a rotating wave increases when the tuyere orientation becomes off-centred . The predicted amplitudes were in very good agreement with the experimental values over a range of gas flowrates between 0.00599m 3/s to 0.01081 m 3/s.

Jan 1, 2000

By Corner NG

A sea bed sampling programme by CRA Exploration Pty. Limited over an area of 12000 km offshore from Westland, Southland and Otago, New Zealand, led to the discovery of the Harvester Prospect, an area of some 67 km2 which averaged 189 mg/m3 gold in surface samples. This area was in water depths of 70 to 100 m and contained a high grade core of 33 km2 which averaged 283 mghn3 gold. The gold recovered was fine grained, averaging 124 microns, and indicated a potential resource of approximately 10 t of gold per metre of thickness. Interpretation of existing seismic and geological data suggested that the gold anomaly may be associated with a unit of sediments 10-40 m thick, probably deposited during a lower sea level stand. Two initial attempts at vibrocoring the anomaly produced inconclusive results. In 1989 a much more powerful vibrocorer with scaled up support facilities and a dedicated 24 It turnaround laboratory were employed. The final results clearly showed that the gold was from an uneconomic surface enrichment.

Jan 1, 1990

The constraints in university courses are lack of hours, high cost of scientific equipment, and poor availability of suitably experienced staff. These have forced the balance away from practical work and towards more theory. Labelling of individuals as either practical, or academic, does not help the inter- change of staff between industry and univer- sities that is necessary to balance idealism and realism. Practical men who do return to universities may lose seniority and find that industry is reluctant to have them back. Academics who specialise too long may concentrate on their research to the exclusion of basic material. It is difficult to operate pilot scale plants in universities because of lack of time, and obsolescent equipment. Small grants from industry might enable tests to be run in research laboratories such as at C.S.I.R.O.. Within universities there may be a need for greater interchange of students among depart- ments, aided by the absence of weighted student unit measurements, as suggested by Aus.I.M.M. and A.M.I.C.

Jan 1, 1984

In the latter half of 1973 a contract was given to Roberts-Holland Joint Venture for the stripping of the southern exhaust airway.The contract was carried out efficiently and relatively cheaply. It was completed 2 months ahead of schedule.The sinking stage and in particular the drilling jumbo proved to be a success and helped produce an above schedule stripping rate.No major problems were encountered with ground conditions or ventilation. A survey of the shaft showed the diameter to be within the set limits of 5·49 m ± 0·15 m.

Jan 1, 1974

By D Dickson

The properties along Ida Avenue in Mosman stand 10 m above the road on an outcrop of Sydney sandstone. Access to the houses is generally via a long steep staircase. The owner of 22 Ida Avenue identified an opportunity to use the natural strength of the rock beneath his property to excavate an underground garage and to provide access to the basement of his property via a 10 m elevator shaft from the back of the garage. This paper will describe the design and construction of this unique and innovative urban development.

Jan 1, 2008

Faced with low prices and weak demand in an oversupplied market, the Australian coal industry must seek to further reduce its costs. The paper examines minesite competitiveness of the open cut coal industry in Australia with some references to the coal operations of M.I.M. Holdings Limited. The make-up of F.O.R. mine costs is analysed in order to identify where efforts should be directed to maintain competitiveness. The scope for mine site improvements through changes to working practices, the application of new technology and cost management is examined.

Jan 1, 1987

By Just GD, Phillips R

The application of high pressure water jet technology to the drilling of longholes in coal has resulted in the development of a system currently capable of drilling to lengths greater than 200m. Field tests at the German Creek Mine have demonstrated directional control of the holes within a 0.5m section of the seam. Initial application of the technique at the German Creek operations is for drilling methane drainage holes. These developments, in three stages, result from support by the National Energy Research Development and Demonstration Council

Jan 1, 1991

By Sheng X. L

The Jurassic coals at Datong are characterised by their strong, massive sandstone and conglomerate roofs which fail suddenly over large areas, crushing pillars and creating destructive windblasts. collapsed areas have exceeded 180,000m2 and windblasts have extended over one km underground and 200m on the surface and have been accompanied by subsidence troughs on the surface. Scientific analysis has researched premonitory signs of caving and the nature of windblasts leading to considerations of alternative mining methods and ways of dissipating the energy of windblasts to reduce their damage and danger..

Jan 1, 1992

Disseminated gold mineralization in the Vunda River area 12 km SE of Lautoka in Viti Levu occurs sporadically in shoshonite volcanics within an alteration area of some 6 km2. No definite intrusions have yet been located though possible intrusions occur toward the centre and on the eastern margin of the area. The nature and distribution of alteration suggests the presence of a co-magmatic mineralizing stock just below the surface.The gold occurs within close spaced fractures and occasionally around the c1asts of breccia and agglomerate.Various types of alteration compatible with porphyry mineralization occur, but to date show no zoning or defined correlation with incidence of gold which occurs in various alteration facies.It is suggested that the gold and trace copper mineralization at Vunda arises from the sub-volcanic intrusive phase (monzonite) of the Sambeto shoshonite (5 m.y.) and is part of an E-W zone of porphyry-type mineralizationtrending easterly to the Kingston porphyry copper deposit at Navilawa.There is a close similarity between the Vunda mineralization and some of the porphyry deposits of alkali affinity in British Columbia, Canada.

Jan 1, 1978

By T Rock

This paper looks at recent advances in the United Kingdom (UK) tunnelling industry with particular reference to the A3 Hindhead Project. A 1.8 km long twin bore tunnel is the centrepiece of the A3 Hindhead scheme, which commenced construction in 2007 and is being delivered under a UK Highways Agency early contractor involvement (ECI) contract. The proposed construction methodology is progressive mechanical excavation of a horseshoe-shaped tunnel with shotcrete installed close behind the face using robotic spraying equipment. The tunnelling medium is a æsoft rockÆ sandstone for which there was little previous tunnelling experience, requiring extensive geotechnical investigations and an innovative approach to lining design. A 240 m long section though sandy material utilising a steel pipe umbrella is also required. This paper describes the development of the tunnel planning and design including the most recent developments in UK road tunnels. The innovative approach to the design of the following is discussed:the æpermanentÆ primary lining,an observational technique allowing optimisation of the steel pipe umbrella design,a plain concrete secondary lining designed for resistance to a hydrocarbon fire, anda spray-applied membrane.

Jan 1, 2008

By C J. N Wilson

The central Taupo Volcanic Zone is a region of intense Quaternary silicic volcanism accompanying rapid crustal extension. Modem central TVZ is the most frequently active and productive silicic volcanic system on Earth, erupting rhyolite at c.0.28 m3 s-1. The rhyolites show no major compositional changes with time, but the total extent of magma chamber zonation has changed with the advent of rifting and crustal extension at c.0.7 Ma. At least 34 caldera-forming ignimbrite eruptions have formed a complex sequence of relatively short-lived, nested and/or overlapping volcanic centres in central TVZ. Taupo contrasts with other large silicic magmatic systems in the exceptionally high frequency, but small size, of caldera forming eruptions. This contrast reflects the thin, rifted nature of the TVZ crust that precludes the development of long term magmatic cycles at Taupo. Within central TVZ, non-rhyolitic compositions have been erupted apparently irregularly in time and space; in particular there is no evidence for a geographic separation of basalts from andesites. TVZ is a rifted arc, but its segmented nature, high thermal flux and voluminous rhyolitic volcanism make it unique on Earth.

Jan 1, 1995

Barrick Gold Granny Smith Mine is currently undergoing conversion from an open cut operation to an underground mine at the Wallaby deposit. The underground project commenced in 2005 with the development of the reserves immediately below the pit and is now currently entering a production ramp-up phase for mining of these two initial surfaces below the pit. With increasing gold prices the owner has been forced to re-evaluate the underground project and has decided to investigate the potential of a deep level mine. This deep level underground mine presents a collection of challenges with the most notable being exploitation of a series of well separated near horizontal lodes ranging in thickness from less than 1 to 20 m. A variety of room and pillar mining methods are employed for extraction with careful consideration to resource recovery and pillar design for long-term stability. Compounding these deep level challenges is a need to accelerate mine level development to maintain the production profile of the mine. This paper describes the challenges, key learnings and outcomes of the studies undertaken to date associated with this project.

Jan 1, 2008

The BHP Billiton Cannington Mine uses paste as the principal method of backfill. The paste consists of mine tailings and cement. The pastefill process at Cannington includes a surface plant where the thickened total tailings stream is filtered using two vacuum disc filters operating in parallel. The filter cake is mixed with Portland cement in a spiral mixer to produce a paste at a specified yield stress and cement content. The initial system design only required paste to be delivered under gravity. In July 2001, Cannington Mine expanded to 1.8 million tonnes per annum. In order to achieve this, production commenced on five new levels underground, 350 metres horizontally from the paste plant. Due to the high viscosity of paste, this distance was too far to transport by gravity. Traditionally, paste has been transported only short distances (50 m) using positive displacement pumps, with very limited success. At Cannington, a conveyor was installed which was designed to achieve zero spillage into the environment. This paper discusses the innovative design strategies used to attain zero harm on the environment whilst conveying a material, which is difficult to transport.

Jan 1, 2002

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

Access to the Rosebery Orebody, which dips into the western slopes of Mount Black at 45¦, has been achieved in sequence by the following means: - A series of adits down to 8 level - An inclined shaft (No. 1 Shaft) sunk internally from 8 level to 14 level - A vertical circular concrete lined shaft (No. 2 Shaft) sunk internally from 4 level to 19 level. Although the orebody has been fairly well defined to 19 level, deeper ore occurrences have been outlined by a series of drill holes decreasing in frequency with depth to 26 level. No. 2 Shaft (sink) was stopped some 10 m below 19 level in order to make an early start on doubled production at West Coast Mines, with the intention of subsequently extending the shaft or of driving a decline from the lowest operating horizon for deeper access. The decline approach was adopted some six years after production commenced from No. 2 Shaft. The reasons for that decision are outlined, together with an account of the constraints and design requirements imposed by commencing by a vertical shaft in the hanging wall of the orebody.

Jan 1, 1982

By Reed M. E, Cloutt B

Particulate samples were taken from the gas space in the settler of the Kalgoorlie nickel smelter using a vertical sampling probe and a specially designed isokinetic sampling probe which also quenched the samples. The vertical sampler was found to give unrepresentative samples. Suction thermocouple measurements of the gas temperature were also made. Using the isokinetic probe samples were taken at four points ranging from near the base of the reaction shaft to the base of the uptake at depths up to 1.5 m into the settler. Dust loadings and the sizing of the samples were determined. These parameters were found to be most affected by sample position and depth. The dust loading decreased along the settler but increased with depth. The loadings varied from zero near the roof to several hundred g Nm 3 near the slag. The dust also became coarser with increasing depth into the settler. Examination of the samples showed them to consist of spherical particles the largest of which were about 500 microns in diameter. The dust was mainly composed of mixed iron/nickel oxides with a little sulphide.

Jan 1, 1991

By Lott JB, Scuffham JB

Until very recently the application of solvent extraction to. the recovery of metals has been considered only for ithose operations where no other process was available. In general, .these operations, have involved metals such as 'f uranium or the rare earths, where the value of metal recovered has been very high. As a result, the tendency has been to consider solvent extraction as a very specialised, high cost technique with minimal application in the base metal industry. Since the mid-1960's this attitude has had to be changed drastically with the development of solvents specifically designed for the selective extraction of individual metals such.ascopper. The result is that solvent extraction must now be regarded as a proven hydrometallurgical technique for the recovery of base metals, and in particular copper. The first significant event in the application of solvent extraction to base metals was the production by General M. Inc. of a compound, designated LIX-63 (R)(1), which was a specific extractant for copper from ammoniacal sns. This did not find a wide application, however, because copper solutions with a pH in the applicable range we more readily treated by conventional techniques.

Jan 1, 1970

ADDRESS BY THE PRESIDENT OF THE INSTITUTE (MR. C. H. MARTIN) IN PRESENTING THE CERTIF1CATE TO SIR GEORGE FISHER, C.M.G.Members of The Institute, distinguished guests, of which there are many, ladies and gentlemen, you are welcome.And might I add a special welcome to Lady Mawby and Lady Fisher and to Sir George's only son Peter, who with his wife, Betty and one of Sir George's three daughters, Helen, are present this evening, and also to Sir Maurice's son, Colin, and Colin's wife, Jay, also in our company.The family presence must surely be a great source of pleasure and satisfaction to all those so intimately concerned.It is hardly. necessary for me to state the sole and only rC'l.son for our presence here tonight, which is to conJer on Sir George Fisher and Sir Maurice Mawby Honorary Membership of The Australasian Institute of Mining and Metallurgy, and at the same time to acknowledge two people who have rendered great service to the mining industry albeit tinged with sadness to all of us in the knowledge that from now on their influence may diminish.

Jan 1, 1976

The "Line of Lade", a generic term by which the great Broken Hill orebodies are collectively known, lies in the County of Yancowinna, New South Wales (NSW) at the south eastern extrenity of the Barrier Ranges. As the township of Broken Hill grew to a city (incidentally it was officially named Willyama but by exerting an enterprising community independence which is still evident today it outplayed officialdom and retained its descriptive name), two major areas of population developed, Broken Hill and South Broken Hill. These two main civic divisions are respectively north west and south east of their dividing line, the surface expression of the orebody. See Fig. 1. The border between the States of NSW and South Australia (SA) is drawn along longitude 1410 East whilst the city of Broken hill's official longitude is 1410 28' 14" East which means it is only 50 km from this political boundary. A latitude of 310 57' 03" South contributes to the harsh climate of high summer temperatures which is not mollified by any significant increase in altitude for Broken Hill is only 300 m above sea level.

Jan 1, 1983

By Hodkinson I, Teale GS

Mount Leyshon is an open cut-heap leaching operation that commenced production in early 1987. Open pit reserves are 6.3 m.t. grading 1.8 g/t Au and 4.8 g/t Ag and expected annual production is 68,000 oz. of gold. Gold mineralisation is hosted in breccias, porphyry plugs and basement rocks interpreted as the roots of a multi-phase Permian phreatomagmatic breccia complex. Mineralisation has the form of veins, cavity fillings and disseminations and is localised by late stage trachytic dikes and sills and dike-like bodies of milled breccia in the northwest corner of the complex. The sequence of mineralisation includes: I quartz-chalcopyrite-molybdenite stockwork veins and pyrite-gold veins with potassic alteration II quartz-chlorite-carbonate-basemetal sulphide-gold veins and cavity fillings with sericitic alteration III quartz-basemetal sulphide-bismuth-sulphide -electrum veins, veinlets and dissemin- ations with sericitic alteration. Mineralisation is interpreted to have formed at 500-300¦C from a predominantly magmatic hydrothermal system related to the porphyry intrusive bodies. Mount Leyshon is a phreatomagmatic breccia with a very different origin to the Kidston magmatic hydrothermal breccia. However the mineralisation style and origin is quite similar.

Jan 1, 1987