Search Documents

In August, 1975, North Broken Hill Limited announced that an intersection of 37.3 m of high grade lead-silver-zinc mineralisation, assaying 26.2 per cent Pb, 495 g/tonne Ag and 21.2 per cent Zn had been obtained at its Mine at Broken Hill, 520 m north-east of its No. 3 Shaft and slightly below the No. 36 level (1581 m). Subsequent drilling confirmed the presence of the extension of the Broken Hill Orebody on the north-western side of the Globe Vauxhall Retrograde Shear Zone and defined 1.8 million tonnes of high grade mineralisation. The area containing this mineralisation was subsequently named the Fitzpatrick Area in tribute to the late Mr. W.E. Fitzpatrick a former Member of the the Board and Manager of the Ccnpany's Broken Hill operations. This paper describes in brief the exploration programme leading up to the discovery, the general geology of the area and the proposed future exploration progranme for further extensions of the orebody within the mining leases of North Broken Hill Limited.

Jan 1, 1983

By Lawless JV

Recent exploration for gold on the Pacific Rim has utilised similarities between active hydrothermal systems and epithermal gold deposits. The major control over formation of such deposits is the hydrology of the ore-depositing hydrothermal system, which varies depending upon its geologic setting.

Jan 1, 1987

The reduction in man's contribution to the Greenhouse effect will only be achieved by a number of small steps. Some steps will absorb carbon dioxide (CO2) from the atmosphere in slightly greater quantities, others will reduce the amount of carbon dioxide generated. This paper deals with the reduction of carbon dioxide by improving the combustion efficiency of petroleum fuels. Until recently most reductions in fuel consumption and air pollution have been brought about through mechanical adjustments to combustion equipment. Since the development of tetraethyl lead, little has been done to chemically modify combustion reactions to improve fuel efficiency or reduce emissions. During the past five years Australian laboratory and field trials with ferrous picrate treatment have demonstrated significant and economic gains in the combustion efficiency of diesel fuels. These studies have revealed that even under ideal conditions in diesel engines, carbon monoxide (CO) momentarily saturates the combustion chamber. This state reduces combustion rates, peak pressure and power and increases the risk of pollution. Theoretical, laboratory and field data are presented which support the mechanism by which the ferrous catalyst accelerates the oxidation of CO to the terminal CO2 thus reducing fuel consumption and the undesirable combustion products accompanying the CO saturation of combustion environments. While this paper deals principally with diesel fuels commonly used in mining operations, the catalytic effect of the ferrous ion is also shown to significantly reduce fuel consumption by petrol engines thereby promising a means to reduce the much larger contributions to the Greenhouse gases by automobiles.

Jan 1, 1989

By Brinkmann J. R

In the narrow stopes of South African gold mines, rockbreaking is carried out by drilling and blasting with safety fuse and igniter cord being used as the initiation system. The fuse/gniter cord system is used primarily because of its low cost, however several limitations of this method include: inaccurate delay time, unreliable firing, inflexible application to varied configurations, and the absence of dynamic interaction between holes. Alternative initiation systems that incorporate millisecond timing are being developed to overcome the limitations of fuse(tgniter cord systems. Current investigations by the Stoping Technology Division of the Chamber of Mines Research Organization (COMRO) into the effects of millisecond initiation are being conducted at a deep test site. Experimental blasts using various millisecond delays and the independent firing of holes with fuse/igniter cord are being studied in order to quantify the influence of delay time on the blasting process and to identify the best methods of applying millisecond initiation systems. The effect of design variables such as delay time, hole firing pattern, stemming, and panel layout are discussed. Blast results including throw distance and direction, muckpile profile and rock cleaning times are used in the discussion of different combinations of blasting variables.

Jan 1, 1990

Efficient project planning during the detailed feasibility to final engineering stages of a project requires not only the accurate prediction of the grade, tonnes and recovery, but their degree of variability as well. An understanding of the major parameters involved in the grade and tonnage estimates is essential, and the communication to those receiving the results is most important. The personnel involved in the project require more than just a global reserves classification. Quality parameters other than grade should be evaluated as carefully as the estimate itself. This paper does not present any novel ideas to overcome or enhance any of this. Rather, it takes a step back and tries to look at the global picture of requirements for proper project planning.

Jan 1, 1987

Large GDP increases in the Pacific Rim countries have been accompanied by similarly large increases in demand for oil products. In the case of residual fuels, this demand has been tempered by the substitution of other energy products such as coal or gas.In the region's developing and newly industrialised nations, it has not been possible to make the very large investements in infrastructure which allow other energy sources to be used for transportation. As a result, GDP growth has been mirrored in the demand growth for automotive fuels. Other non-sustitutable products such as lubricants have also benefitted by the region's GDP growth.The combination of a number of years of sustained growth, coupled with increasing quality requirements is now stretching the upgrading capacity of the region's refineries. If, as seems likely, the region continues to enjoy a high GDP growth rate, then this will be accompanied by increasing reliance on finished products coming out of the Middle East. The owners of the most simple form of refinery in which crude is simply distilled and the naphtha reformed into petrol will face major capital investments. If they decide not to bear this cost, they will face increasing problems in selling their surplus residual fuel oil at an economic price. Quality will become an increasingly important issue. Not only in the well publicised areas such as unleaded petrol, but also for products such as lubricants which play a major role in the efficiency of modem equipment. Quality of service such as hours of opening, ease of access, and service station facilities will also become increasingly important as the oil companies use these to attract customers and gain brand differentiation.

Jan 1, 1990

The C.S.A. copper lead zinc mine, located seven miles north of Cobar in Central Western New South Wales, is the largest known mineral occurrence in the Cobar Mining Field. Hosted by the steeply west dipping, west facing sediments of the Cobar Group, the generally discordant orebodies occur within a strike width of 600 ft and an overall strike length of 1200 ft. They comprise lenticular steeply north pitching and east dipping zones of sulphide mineralisation which range in composition from massive pyrite-sphalerite-pyrrhotite--galena to less massive pyrite- pyrrhotite-chalcopyrite varieties. The thinly bedded siltstones, shales and graywackes hosting the mineralisation appear to have derived many of their constituents from volcanic sourcesä They have been metamorphosed to the greenschist facies of regional metamorphism. At least two stages of deformation and folding have occurred. The first stage folded the rocks on a south pitching fold axis into their present configuration, and super- imposed a strong axial plane cleavage which subsequently guided the emplacement of the mineralisation. The second stage of deformation is considered to have controlled the zonal distrib- ution of the orebodies and the appropriate fold axis appears to coincide with the long axis of the orebodies.

Jan 1, 1969

By Wilkins L. G

Ore recovered by North Broken Hill Limited as a result of mining operations at its Broken Hill leases is obtained, at the present scale of working, in the proportions of 80% from the North mine and 20% from the British mine sections, and is composed mainly of a silver bearing, sulphide lead and zinc mineral, in association with the gangue materials mentioned later in the text.The lead-zinc sulphide lode at the North mine is deposited in folds in pre-Cambrian sedimentary schists. These folds pitch north-east at approximately 40° and dip north-west at approximately 60°. In plan the deposit appears as two lenses designated on the mine as the "Southern" and "Northern" ore-bodies.The Southern ore-body yields the main tonnage of crude ore. The sulphide mass here overlies a heavy layer of rhodonite which persists with the pitch of the lode. In the central section of this ore-body the sulphide zone is coarse grained and of high grade with a wide range of minerals in the gangue dilution. Quartz, garnet, ftuorite, rhodonite, and felspar are common, whilst chalcopyrites, pyrites, pyrrhotite and green felspar are often present. The Northern ore-body is dolomitic to siliceous in nature. Crude ore obtained from the British section is predominantly...

Jan 1, 1940

By Reichardt Y

Fine feed fractions in the size range from 1 to 40 ¦m of materials with different hardness as limestone and silicon carbide have been stressed in two different devices. A tungsten-carbide-blodc allows a single stressing with a pressure up to 2000 MPa and a 4-piston-block enables a multiple stressing procedure in which the material bed is stressed in alternating directions with a pressure up to 700 MPa. The experiments show energy absorption as the major factor for the interparticle breakage of hard material, like quartz, zircon silicate, silicon carbide and smelted oonindum, pressure, however, does not influence the results within the investigated range from 100 to 700 MPa and even up to 2000 MPa for corundum. But the breakage of the middle-hard limestone depends on the pressure so far as more fineness can be produced if the same energy is introduced at a lower pressure level. The creation of very fine and microfine fragments decreases strongly with increasing hardness of the feed materiaL The energy consumption for producing microfine material with a multiple stressing procedure on a particle bed is much lower than that one of a usual milling process. But this procedure needs a classification with a seperation cut at a couple of microns, which is not easy to accomplish.

Jan 1, 1993

By Rayner J. G, Leckie J. F, Moorehead C. F

The Coronation Hill gold-platinum-palladium prospect is located in the valley of the South Alligator River (latitude 13'35'S, longitude 132'36'E), about 80 kilometres east of Pine Creek in the Northern Territory. Coronation Hill was one of thirteen sites in the South Alligator Valley at which uranium was mined between 1955 and 1964 after initial discovery by the Bureau of Mineral Resources in 1953. Most of the mines were operated by United Uranium No Liability. The Sleisbeck mine 25 kilometres south of Coronation Hill was operated by North Australian Uranium Corporation and the group of mines at Rockhole about 20 kilometres to the north-west of Coronation Hill was operated by South Alligator Uranium No Liability. The uranium mine at Coronation Hill produced about 26000 tonnes of ore averaging 2.6 kg/t U308 with an estimated average gold grade of 10.4 g/ gold. Gold was commonly associated with the uranium mineralisation and was recovered at the gravity treatment plant at El Sherana. Gold was also recovered in 1986 by Pacific Gold Mines Limited by treating the tailings from the Moline and Rockhole uranium leach plants at a CIP plant at Moline. With the completion of uranium contracts in 1964 mining in the South Alligator Valley ceased. Exploration for uranium continued in the area during the 1960s and 1970s with no success. The Coronation Hill Joint Venture (BHP Gold Mines Limited 45 per cent, Pioneer Minerals (Gold) Pry Ltd 45 per cent, Notgold Limited 10 per cent)carried out the first exploration specifically targetted at gold in 1984 with the drilling of five vertical drill holes which indicated high potential for a substantial gold resource at Coronation Hill with no associated uranium. The Joint Venture has sub- sequently drilled about 25000 metres of diamond drill holes at Coronation Hill alone. Analytical results from 1985 drilling established that platinum and palladium were associated with gold. An indicated resource of 3.49Mt at 5.12g/t Au, 0.21g/t Pt and 0.56g/t Pd has been calculated using a lg/t Au cut off.

Jan 1, 1991

By Woodcock J. T, Zhu T, Sparrow G. J

A lead-zinc-pyrite flotation middling was pressure oxidised to give residues containing iron hydroxy sulphates (a mixture of basic iron sulphate (BIS) and a hydrated iron sulphate (HIS)) and lead sulphate. Direct thiourea leaching of this residue gave over 90 per cent extraction of gold and silver, but thiourea consumption was high (56 kg/t) because of soluble iron(M) in the residue. Attempts were made to decrease the thiourea consumption by removing the water-soluble iron(M) or reducing it to iron(II). Water washing of the pressure oxidation residue removed most of the hydrated iron sulphate but little of the basic iron sulphate. Iron removal was only 12-20 per cent, depending on the number of washes, from one sample which was low in HIS, and 40-45 per cent in another which was high in HIS. Iron extraction was not appreciably increased by using dilute sulphuric acid (with or without additions of sodium sulphite), dilute phosphoric acid, or sodium chloride solution (150 g/L NaCI). Direct thiourea leaching of the water-washed residue gave over 90 per cent extraction of gold but only 49 per cent of silver, with a thiourea consumption of 27 kg/t. However, the application of a water wash followed by reduction of dissolved iron(III) with sodium sulphite in the presence of thiourea, and then thiourea leaching resulted in over 98 per cent extraction of gold and silver for a thiourea consumption of 26 kg/t.

Jan 1, 1991

By Barnett DW

Financial risk analysis provides the tools to examine the uncertainty of capital decisions in new mining ventures. This paper explores the methodology by which financial risks can be studied and quantified. The most commonly used risk evaluation methods, such as sensitivity analysis and discount rate adjustment, are presented as an introduction to a more comprehensive discussion of stochastic methods of discounted cash flow analysis using Monte Carlo sampling. The discussion is illustrated with examples of a stochastic discounted cash flow. The advantages of Monte Carlo sampling in risk analysis are discussed together with its problems, particularly those originating from the correlation amongst the variables that determine the economic output of a mining venture, and the difficulties created by insufficient data, imperfect knowledge and complexity. The paper also surveys the most commonly used software used in risk analysis.

Jan 1, 1994

By Rowlands N. J, Zimmermann D. O

The Engel Model search simulator is described with particular emphasis on preparation of input parameters. The computer has a "black box" role in the same way a telephone or radio is a "black box" in communications. A search technique (sensor) is selected and applied in two stages of'search, namely, reconnaissance and detailed. The model relies on knowing and quantifying the parameters of the target sought and the search technique; this is usually done by analogy studies from available literature and experience. The parameters are then balanced by feasibility studies on the search area. Case histories show that the study makes the user aware of what he is likely to find rather than what he wants or needs to find to be viable. Two case histories are presented: one for Mississippi Valley type lead- zinc deposits and another for stratiform copper. The first study showed particular benefits in the input stage and highlighted the fact that one could expect a lot of encouragement by way of interesting results but with little chance of finding the high-grade,

Jan 1, 1974

By A R. Sale

This paper highlights two aspects of the mineral sands industry in Australia: the development of the industry from approximately 1870 through to 1980, and the author’s experience in the industry from 1966 to date.The first real heavy mineral (HM) mining in Australia started in 1870 with the mining of heavy mineral slicks on the beaches along the east coast of Australia. The real potential of Australian heavy minerals was however only realised in the 1920s with the first production of a heavy mineral concentrate that was shipped to Canada for processing. Post WW 11 and the Korean War, Australia was the largest producer of mineral sands products in the world as well as a significant developer of associated separation equipment and technology. The number of producing companies in the east coast peaked at 33 in 1957, was reduced to ten by 1965, and subsequently further reduced to five in 1980 as a result of potential mining areas being declared National Parks or Conservation Reserves. Today there is one company, Unimin Australia Pty Ltd (formally Consolidated Rutile Ltd) operating on the east coast. In contrast there were three companies on the west coast in 1965, four companies in 1980, and four companies today (albeit not the same companies).There have been considerable ups and downs for the industry in Australia, however world wide it was renowned in the past as being an industry that attracted numerous interesting and innovative characters that played a major role in developing it into the vibrant industry that it is today. This, given the current climate, is predicted to continue into the future.The author has been continuously involved in the industry for over 45 years from 1966, initially as an electrician at Consolidated Rutile Ltd culminating in the role of General Manager/President of Iluka Resources Limited USA, prior to his retirement in 2009. His exposure has been world wide and has covered all aspects of the industry but in the main focused on project development and operational areas. During this time there have been significant technological advances, yet to some extent the basic principles have not changed at all. Some of the most noteworthy advances include the development of the Wright Spiral in 1977, the development of the Reading High Intensity Wet Magnet (WHIMS), the rare earth magnets, the CRL floating thickener and the improvement of analytical techniques. From a safety, health and environmental perspective there has been significant advances that the industry has much to be proud of. These include wetland restoration both in Australia and in the US, the restoration of farmland in Virginia and Capel, and the re-establishment of native species, for example at Eneabba and Richards Bay to name but a few.

Oct 5, 2011

Designing for early access to deep orebodies is an essential driver for improved project payback. Vertical shaft sinking techniques have been developed to allow concurrent mine level excavation while continuing to sink. Project cash flows can also be improved when simultaneously deepening existing shafts beneath operating hoisting systems. Further economic advantage has been realised through creative sinking sequencing in twin ventilation/service shaft projects. A fourth technique to reduce project schedules involves partial shaft barrel equipping allowing unrestricted access to construct stations and continue with level installations. This approach reduces interference with barrel sinking activities to insignificant proportions. This paper reviews how these approaches have added significant value to actual shaft sinking projects, as assessed from a contractorÆs perspective, and discusses some of the practical issues to be addressed when planning future projects. Designers need to take cognisance throughout all project engineering phases of the adage that you are only sinking when cleaning the face. Cleaning can only be sustained when there is sufficient hoisting capacity.

Jan 1, 2005

By Oda Y, Hashiuchi M

In the smelting section, flexible fuels such as coal or coke are used in place of heavy fuel oil in order to utilize energy sources more efficiently. Heat recovered from the off gas of the furnace has been converted by the waste heat boiler into steam, which is used for self power generation and for heating or maintaining various temperatures. The amount of the recovered steam in the smelter is currently increasing due to maximum utilization of powdered cokes. The heat source required to maintain the temperature of the electrolyte in the tank house is electric power and steam. However until recent year this steam was provided by its own heavy oil combustion type boiler in the tank house since the amount of steam consumed in heating the electrolyte is large. Though experimental work over the last few years has shown the advantages of reducing steam in the tank house by fully covering the cell, the implementation of the full cover can lead to other operating problems. However various improvements, mainly the covering of the cell with a simple device, have led to greatly reduced steam consumption. As a result, steam for the tank house is now provided by the waste heat boiler only bringing more efficient energy usage.

Jan 1, 1987

Most coal mines in Chongqing Area are highly gassy mines and liable to outburst of coal cnd methane. In order to harness mine environment and raise the Prodction capacity, methane predrainage is generally taken as a main preventive measure against outburst by all mines. In the recent ten years, the drainage volume per year has increased from 38.25 million m3 to mote than 100 million m3 with a volume over 12 m3 per tome of coal. In some mines, the draining rate is approaching to 50 percent, the rate in mining districts is up to 60 to 70 percent. The predrainage volume accounts for one fourth of total drainage volume. All these have effectively prevented the occurrence of coal and methane outbursts.This is the current situation of methane predrainage in coal mines in Chongqing area, the methods of predrainage to prevent outbursts and related parametres comprise:1. methods, technologies, supervision and effect of predrainage in different geological and mining conditions,2. the change of methane parametres pre-and post-drainage and the analysis of the effect of methane predrainage to prevent outbursts, and3. ways to improve the effect of methane predrainage.Thus the safety, reliability and production of Changqing Coal Mines will be enhanced.

Jan 1, 1991

By Aziz NI

There are a number of methods available for the determination of the fracture toughness of rock. Some of the most recognised methods include the hollow pressured cylinder, the short-rod, the chevron - edge-notched round bar in bending and the disc-shaped compact specimen. Most of these tests are difficult and expensive to conduct. In this paper the simple Brazilian testing of discs for tensile strength has been used to determine their fracture toughness. Tests were conducted on six different rock types and the values of the fracture toughness obtained for each type are in close agreement with the results of the well recognised the chevron edged types. Details of the tests, and analytical validation of the technique, are presented

Jan 1, 1992

The man in the street (and no doubt most members of the Institute) thinks of wire, if he gives it any thought at all, as a most commonplace commodity. It is an accepted necessity, and like most necessities is taken for granted, unless a shortage in one or other of its multitudinous forms or products causes inconvenience.For many years Australia has ·been a large consumer of wire, particularly for fencing. With the rapid development of secondary industry the demand has increased in both size and character until at the present time much of the wire produced in this country is used as raw material for subsequent manufacturing processes. The call has been of so varied a nature that the Newcastle Wire Mills now turn out a greater variety of wire types than any other single plant in the world.In this paper, the aim is to provide a picture of the manufacturing, properties, and uses of wire. No attempt is made to cover the subject in any detail, as the field is much too broad for anything other than general treatment. Many phases, particularly in regard to manufacturing processes, are, therefore, dealt with cursorily, but it is hoped that the paper will, without delving too deeply into the technical aspects of Wire production, give a general appreciation of:- (a) How steel wire is made. (b) The remarkable physical characteristics obtained by judicious combination of chemical composition, heat treatment, and subsequent cold work. (c) The uses of steel wire.HISTORY.Best known of the early references to wire is that appearing in Exodus, where mention is made of gold wire being used for the sacerdotal robes of Aaron. However, the period in question, about B.O. 1491, is comparatively modern history as far as wire is concerned, for specimens believed to have been made about B.O. 4600 have been found. It is fairly certain that the Egyptians produced iron wire in B.O. 4000. Of particular interest is the

Jan 1, 1947

By Sans H

The geostatistical Discrete Gaussian (DG) model is demonstrated to be capable of providing an effective means of implementing change of support for Enterprise-style mineralisation and thus providing reliable global recoverable resource estimates. At Enterprise, sample grade distribution proves to be highly positively skewed, therefore significant deskewing of the histogram and reduction of variance occurs when going from sample to block support. The DG model was experimentally tested in'the Southern Primary Zone (SPZ) at Enterprise, where high anisotropy ratios and pronounced short range structures are observed in variograms. The experimental test was run for a change of support for which the variance reduction was. approximately 60 per cent. This reduction is similar to that predicted by Krige's Relationship ('the volume-variance relationship') for the practical situation of a change of support from 5 m vertical blasthole samples to 3 m x 8 m x 5 m selective mining unit (SMU) blocks. The DG model was found to correctly predict the grade tonnage relationships for a wide range of cut off grades. The experimental test indicated that, given a representative histogram and variogram, the DG change of support provides a computationally efficient and practical means of reliably assessing global mineable resources at the early stages of a mining project. Further, it allows a range of selectivity strategies to be meaningfully and comparatively considered prior to mining.

Jan 1, 1995