Search Documents

Types of structure found in 'Jest Australian beach sands are described. Their recognition by geostatistical methods follows nth a discussion of the effectiveness of sampling patterns. Examples of structures are given, and an account of their effect on valuation procedures.

Jan 1, 1977

By Kuganathan V

The processing of black coal in Australia segregates waste in the form of coarse reject and fine tailings. The coarse reject is relatively easy to handle, while the tailings can be problematic. Conventionally, the two waste materials are disposed of separately, the coarse reject in dumps, and the tailings in man-made containments. Aqueous tailings slurry is pumped to a 'wet' tailings storage, where the fine particle size of the tailings limits dewatering. Their low bearing capacity and high compressibility result in tailings deposits being difficult to rehabilitate. Disposing of the waste streams separately moves away from the heterogeneous mixture in the undisturbed ground, and concentrates potential problems with each waste stream. The feasibility and desirability of the co-disposal of tailings and coarse reject by combined pumping is demonstrated. This technique is in operation at Jeebropilly Mine and is proposed for a number of other coal mines.

Jan 1, 1992

The Perth Mint receives gold and silver from various sources for evaluation and refining. The metals are received in many forms and vary widely in assay. Refining is carried out using the Miller Process and the and the resulting market quality bullion is sold in a range of weights and alloys to suit the international bullion market and public demand. INTRODUCTION The Perth Mint was established in the late nineties as a branch of the Royal Mint, London, to refine the gold from the newly established gold- fields in Western Australia. The branch was opened for business in June, 1899. After refining, the bulk of the gold was used in the manufacture of sovereigns and half-sovereigns. Nowadays, although most of the gold received comes from the W.A. goldfields, some gold is deposited by producers in other states and in Papua-New Guinea, as well as scrap and trade wastes from manufacturing jewellers and old jewellery from the general public. Silver is deposited in the form of old silverware, recoveries from-photographic processes etc. Gold or silver may be lodged at the Mint in person, through a bank or other agency or by registered post. Telegraphic advice is usually given when gold is sent by the latter, so that insurance may be effected.

Jan 1, 1982

By McClarnon D. J

This paper aims to provide the reader with an insight into the field of computer graphics and Virtual Reality (VR), and show how both have been applied to the general area of Free Steered Vehicle (FSV) operations underground. It first explains this developing computer technology and explains its advantages over existing CAD based solutions. This paper deals with the graphical applications and implications of building models within a computer's memory. It then continues to describe the problems with Free Steered Vehicle operations. The work already carried out in the field of VR is explained, and the production of a VR system addressing the problems with fitting cameras to aid the driver's field of view is detailed. Another possible use of VR is also explained - the concept of risk regions, demonstrating its uses in the examination of proposed operational methods. Examples of possible uses are given, and its potential advantages over existing methods discussed. A case study of a computer-generated video involved with the safety of operations of FSVs is also presented. This addresses the precautions that pedestrians should take to ensure safe working in areas where FSVs are operating. This paper then concludes with possible further applications for computer graphics and VR, and the on-going research into these two technologies.

Jan 1, 1995

THIS paper deals with the handling of the various materials used in the 100-ton zinc plant at Risdon, and, in view of the magnitude of the works, the configuration of the ground covered by these works, the variety of the rnaterials used, and the large quantities, a very attractive and interesting subject is opened.The works are situated on the right bank of the River Derwent, about four miles above Hobart, the capital city of Tasmania. The Risdon works cover a space of 149 acres, the area being :3800 yards long by 2800 yards wide, and the elevations vary from 6 ft. above high-water mark at the wharf and foreshore to 163 ft. above high-water mark at the power station, these being the limiting points as regards elevation which are considered in this paper. Throughout the paper elevations are given in feet above high-water mark. Fig. 1 shows a general view of the works taken from the opposite bank of the River Derwent. The wharf is clearly shown, with SS Kekerangu loading residue; behind the wharf is seen the inclined conveyor leading to the cakine bin; further up the hill is the leaching division. No. 1 haulage runs to the left of this up to a point on the left of the power station, the large reinforced concrete building at the top of the hill. Below this is the cell room, the largest building on the plant. The roasting division, not very clearly seen, lies at the foot of the main stack, and the casting division lies to the left of this, between the leaching division and the cell room. A large wharf has been construl'ted alongside the works. This wharf is 880 ft. long and 60 ft. wide. It is capable of berthing large overseas steamers, as at low tide there is a depth of :30 ft. of water. The rise and fall of the tide at the wharf is 4 ft. 6in., and the river is navigable at all states of the tide. Just above the company's wharf...

Jan 1, 1923

By Daniels E. J, Morgan W. A

In response to the increase in consumption of galvanised steel for automobiles in the last decade and the problems associated with remelting larger quantities of galvanised steel scrap, a process is being developed to separate and recover the steel and zinc from galvanised ferrous scrap. The zinc is dissolved from the scrap in hot caustic using anodic assistance and is recovered electrolytically as dendritic powder. The dezinced ferrous scrap is rinsed and used directly. The process is effective for zinc, lead, and aluminum removal on loose and baled scrap and on all types of galvanised steel. The process has been pilot tested for batch treatment of 900 tonnes of mostly baled scrap. A pilot plant to treat continuously loose scrap, with a design capacity of 48 000 tonnes annually, has been in operation in East Chicago, Indiana since early in 1993. The first 450 t of scrap degalvanised in the pilot plant have residual zinc below 0.01 per cent and sodium dragout below 0.01 per cent. Use of degalvanised steel scrap decreases raw materials, environmental compliance costs, and opportunity costs to steel- and iron-makers. Availability of clean degalvanised scrap may enable integrated steel producers to recycle furnace dusts to the sinter plant and EAF shops to produce flat products without the use of high quality scrap alternatives such as DRI, pig iron, or iron carbide. Recycling the components of galvanised steel scrap saves primary energy, decreases zinc imports, and adds value to the scrap. The quantities of zinc available by the year 2000 from prompt and obsolete automotive scrap will approach 25 per cent of zinc consumed in the major automotive production centres of the world. Zinc recycling from galvanised steel scrap, either before or after scrap melting, will have to be Implemented.

Jan 1, 1993

The discovery of bauxite in 1955 at Weipa on the NW coast of Queensland's Cape York Pen- insula enabled Australia to join the Caribbean and West Africa as one of the major world sources of bauxite. Weipa, today, is the largest bauxite mining operation in the world and holds a significant position on the world bauxite scene as the operation 1. supplies 15 per cent of the Western World's metallurgical grade bauxite requirements, Z. produces 50 per cent of the world's demand for abrasive grade calcined bauxite, and 3. is the world's largest bauxite shipp ing port.

Jan 1, 1978

North Flinders Mines Limited (N.F.M.) is an Australian-owned mineral exploration and mining company based in South Australia. In the 1970's it researched the prospectiveness of the Tanami (central western region of the N.T.) for the identification of possible economic gold deposits. Having outlined the potential for such a deposit at The Granites (550 km. N.W. of Alice Springs), it marked out and in 1975 applied for the grant of eleven gold mining leases (G.M.L.'s) under the provisions of the then Mining Ordinance. This application was deferred by the Commonwealth Government during the time of the Aboriginal Land Rights Commission (Woodward), subsequent enactment of legislation and land claims. In 1980, the Walpiri and Kartangarurra-Kurintji land claim encompassing the G.M.L.'s, became Aboriginal land. It therefore became necessary for N.F.M. to negotiate a mining agreement with the Central Land Council (C.L.C.) represent- ing the Traditional Owners, before the G.M.L.'s could be granted. In August 1983, the C.L.C. and N.F.M. concluded an agreement to enable the grant of mining interests necessary for the devel- opment of The Granites Gold Project. In several ways this agreement is unique in That:

Jan 1, 1984

By Corrans I. J

A wide variety of copper-bearing gold ores exist throughout the world which have yet to be processed economically for gold recovery. The copper minerals present in these ores can be many and varied and usually result in high cyanide consumptions and problematical levels of copper in leach solutions. The copper content is often assessed as being of nuisance value as the ores are generally of the grade or type which can support neither a copper project nor a straight gold project, due to the interference of copper. Many of these problematical gold-copper ores could possibly be processed economically for gold recovery using a novel ammoniacal cyanide leaching system which utilises a copper-ammonia-cyanide complex as an effective lixiviant for gold, yet limits copper dissolution and conserves cyanide. Results from recent testing have promoted a re-evaluation of the economics of treating some gold-copper ores. This paper describes the novel leaching process and discusses the conditions employed to treat a variety of gold-copper ores.

Jan 1, 1992

By A G. Grice

Surface disposal of mining processing wastes is usually perceived as an undesirable consequence of meeting societyÆs needs for metals and minerals. Environmental disasters associated with the discharge or storage of such wastes, though infrequent, can have very damaging consequences for the environment and the industry. Reducing or eliminating the potential for such events may be achieved by placing some or all of these processing wastes back into the voids created by the mining operations. Processing operations may limit or enhance the opportunities for using tailings and other waste products as a backfill material. Backfilling is a truly multi-disciplinary process and requires the informed involvement of mining, metallurgical, engineering and environmental specialists. This paper describes the range of fill types currently being used in Australian mines, particularly those utilising processing wastes as constituents. It focuses on how processing operations can affect the suitability of these materials for the various types of fill, the resulting fill properties, fill performance and costs.

Jan 1, 2002

The operation of quarries for the production of crushed stone and aggregates, depends heavily on rock blasting efficiency, which usually represents a major share of total production costs. After investigating the causes of this situation, a series of technical aspects have been detected, and they are described for the purpose of contributing to the minimization of costs, which also reduces the effects of blasting on the environment. Utilization of empirical design methods, of inadequate explosive types, and of erroneous drilling pauems with respect to rock properties, are the main factors to be corrected, as a consequence of poor engineering criteria, with scarce use of computational methods and field instrumentation. Several concepts of blasting optimization are pointed out, and their application to industrial operations in a Portuguese limestone quarry indicated clear trends for the reduction of production costs, as well as some of the deleterious consequences of blasting on the environment.

Jan 1, 1990

By Lyman G. J

The volumetric distribution of valuable mineral, or phase, within a set of particles is called the liberation distribution. To optimise a mineral processing plant it is necessary to know the liberation distribution in most of the streams, especially those adjacent to separation devices. Possibly the most common method of analysing ore particles is to section sets of similarly-sized particles. However, the observed sections can appear liberated even if the particle is composite. This means that the 'apparent' liberation distribution can be very different to the 'actual' liberation distribution. This discrepancy is called stereological error. One must then somehow estimate the actual liberation distribution using the apparent liberation distribution. This problem is called the liberation distribution problem and its solution is the subject of this paper. The solution is based on a sorting algorithm which uses geometric probability equations. These equations are based on the assumption that sectioning is isotropic and uniform. Apart from these assumptions the equations are completely independent of particle shape or texture. The algorithm is verified by numerical simulation and experimental methods. For the numerical simulations the correspondence between the actual and estimated liberation distributions is excellent. For the experimental methods, the agreement is not as good and appears to be due to experimental errors.

Jan 1, 1995

The paper highlights the conceptual developments in rock mechanics applied to quantify the effect of bolts in the stabilization of joints and yielding soft rocks. NOTATION Aa = stress change after excavation Eä EE, Eä = moduli of intact rock, single joint and jointed rock Eb = elastic modulus of the bolt k, = normal stiffness of joint Ab = cross section area of the bolt A, = area of influence per bolt ab = axial bolt stress e, = axial strain of the bolt eä e,, ej, = strains of intact rock, joint and jointed rock Ai = area of the joint ,r+ = shearing resistance of the bolt (at the joint) a = normal stress at the joint plane aäa3 = major and minor principal stresses c;, 4i; = cohesion and friction angle of the joint 0 = angle between the bolt and the joint a = inclination of the joint to the vertical axis P = bolt density parameter u, = convergence of unsupported tunnel section u, = convergence of bolted tunnel

Jan 1, 1992

Land is of extreme importance to citizens of Papua New Guinea and is fundamental to most of their customs and values. Because of this, matters to do with land cannot easily be separated from other matters to do with the community. Good relation-ships with landowners and the community surrounding a development are, indispensable ingredients that -must flavour and colour the entire ;operati on .

Jan 1, 1994

This paper is written as a supplement to that of Edwards, Baker and Knight on "The Geology of the Wonthaggi Coalfield" 1, the West Area pit being in an early developmental stage at the time of their paper. The thin seams to the west of Dudley Basin 2 had beenknown for many years but it was not until 1935 that it became necessary to work them. The West Area Pit came into production as Dudley Area Pit approached exhaustion in 1937. From available information it was estimated that early work would be in a 36in. bottom seam. The present top seam was not included in the reserves, but it was to be extracted where it proved thick enough for economical working.THE SEAMSEdwards, Baker and :Knight (1944) had insufficient information to correlate positively the West Area seams with those in the Dudley Basin. Their opinion was, however, that they were a westerly extension of the Bottom Seam. Since then the driving of the present north-east heading towards No. 4 Bench McBride Tunnel has established that the West Area seams are those worked as Bottom Seam in the Dudley Basin. West Area Top Seam is a seam that occurred above the Bottom Seam in the Dudley Basin. Only sporadic attempts have been made to work it in Central Area, because 30in. was considered an economic minimum height until recent times. This seam should not be confused with Top Seam, Dudley Basin, which lies some 300ft. above the bottom seam measures and except in isolated areas over deeper workings has been eroded away in West Area.

Jan 1, 1953

By Christie AB, Bull VH

The geological environments of gold deposits are reviewed in relation to the strong resurgence in exploration for gold since 1979. The resurgence is due mainly to New Zealand's geological endowment with gold and its history as a gold producer. Major past production was from Cenozoic placers of Otago and Westland, late Cenozoic epithermal deposits of the Hauraki Goldfield, and the respective Paleozoic and Mesozoic lode deposits of the Reefton and Otago Goldfields. These same geological environments are the targets of current exploration, mainly in extensions of previously mined deposits. On the Westland and Otago Goldfields alluvial and fluvioglacial gravel placers, mainly representing lateral and depth extensions of previously worked ground, are being mined and prospected. Gold production in 1984 was exclusively from these deposits, and the development of mobile concentration plants has resulted in a great increase in mining activity. Mineralised zones adjacent to previously mined lodes in the Hauraki Goldfield, Reefton Goldfield, and at Macraes Flat (Otago Goldfield) are being intensively explored. At Waihi (Hauraki), an open-pittable resource of about 10 million tonnes of ore has recently been delineated. Some new deposit types and little explored environments are also receiving attention. They include: gold-sulphide quartz veins hosted in an alkaline granite dike in west Nelson; hot spring type gold deposits in fossil geothermal (epithermal) systems of Northland, the Hauraki Goldfield and the Taupo Volcanic Zone; and marine placers off the West Coast where an area of auriferous gravels has been outlined near Hokitika. There is potential in known deposits and prospects currently being evaluated for a large increase in gold production by the early 1990s.

Jan 1, 1986

By Mayer TE

The Granites Goldfield is located 550 km northwest of Alice Springs. Mineralisation was discovered in 1900 and intermittently worked along nine km of strike until the early 1950's, yielding a recorded production of 470 kg of gold. The geological environ- ment, pre-existing exploration drilling results, and an optimistic view on gold, prompted acquisition of the property by North Flinders Mines Limited in 1975. An agreement was signed with the Central Land Council in August 1983 and drilling commenced in the same month. In the past, gold was won from alluvial deposits, rich quartz veins and lower grade, disseminated stratabound mineralisation. The last is contained within a distinctive unit in the Mt. Charles Beds, of the Early Proterozoic Tanami Complex. This informally named "Host Unit" is a metamorphosed, chemical- pelitic sediment. The schist contains variable proportions of amphibole, quartz, garnet, clinopyroxene, carbonate and sulphide, inter- calated with recrystallised chert beds. Free gold occurs in several mineralised horizons within the Host Unit, generally conformably distributed within lithologic bands or at lithologic contacts. The Host Unit occurs within a sequence of metamorphosed pelitic sediments and intermediate volcanics. Although mostly confined to the Host Unit, stratabound gold mineralisation also exists in both Footwall and Hanging Wall Schists, usually within zones displaying certain Host Unit characteristics. The deposits may be loosely categorised as being of banded iron formation (bif) type, although some important differences are noted between them and classical bif type orebodies.

Jan 1, 1984

By Mutton B. K

Hilton Mine is being developed as an integrated component of the Mount Isa operation, to achieve continuity of silver/lead/zinc production well into the next century. The mine has a chequered history from its discovery in 1947 through several periods of intense development activity, each of which has been curtailed due to the further development of the Isa Mine operation. This era has now passed; to sustain increased production rates at Mount Isa, there is a requirement for Hilton ore in 1989. The decision was made in 1983 to accelerate the programme of Hilton development by installing skip hoisting facilities in the main service shaft (P49), to facilitate the development of the mine to pre-production status. The Hilton development plan provides for the mining of selected orebodies, a broadening of the underground exploration drilling programme, and the establishment of significant mine infrastructure. Several technical challenges have been identified as important. The Hilton orebodies, although occurring in the same rock type as Isa Mine, are more faulted, jointed and intersected by intrusive dykes. The ore is more variable in terms of ore continuity, boundaries, grade and metal distribution and the mineralogy more complex. As a consequence the development of this project consists of a co-ordinated programme of mine exploration and development, rock mechanics investigations and metallurgical research and development work. Production will commence in 1986 at a rate of 1000 t/day using mechanized cut and fill techniques. It is planned to introduce sublevel open stoping and by 1996/97 the production rate will be 2.5 million t/yr.

Jan 1, 1986

While convergence of plates at a subduction zone produces shortening at the toe of the overriding plate, this deformation is localized to the frontal 100 km or so of the plate. There is increasing evidence that the state of strain in back-arcs, volcanic arcs, and possibly the entire forearc is extensional. The most likely cause of this extension is rollback of the subducting plate and trenchward advance of the overriding plate. Arcs are thermally weakened, and are activated repeatedly through time. The primary expression of the extensional state of strain is spreading of the weak arc material, either by splitting the arc or by back-arc spreading behind it. This study presents evidence for extension of volcanic arcs from an analysis of the moment tensors of shallow earthquakes (

Jan 1, 1990

By Johnson N. W, Quast K. B

Over the years there have been occasional references in the literature to the activating effect of cyanide in galena flotation with xanthates. These have usually been associated with the processing of lead-zinc or copper-lead-zinc ores. Bubble contact curves for the pure galena-xanthate system show a flotation edge at pH 10.4 independent of sodium cyanide concentration which was thought due to hydroxyl ion, not cyanide ion.Flotation tests were conducted on samples of Mount Isa lead-zinc ore using varying concentrations of sodium ethyl xanthate and sodium cyanide. At low collector concentrations, galena recovery kinetics improved with sodium cyanide addition, and the higher the cyanide concentration, the higher the galena recovery rate. At higher collector concentrations, galena recovery rate was independent of sodium cyanide addition.For a given collector addition, the lead grade-recovery curve shifted to an improved position with increasing sodium cyanide level. For the same recovery there was an increase in the lead grade with increased sodium cyanide addition, and this increase was most dramatic at high sodium cyanide concentrations.The presence of sodium cyanide during the grinding of Mount Isa ore caused surface passivation of the iron sulphides and possibly the sphalerite.These sulphides, therefore, reacted with less of the oxygen present in the pulp, hence more oxygen was directed to the surface of the galena. This resulted in an enhancement in the total amount of xanthate adsorbed on the galena that is reflected in the improved flotation response of that mineral.

Jan 1, 1990