Search Documents

By G Baird, M Seto

Reliable evaluation of in situ stress is an important phase in the analysis and design of underground excavations, particularly for evaluating the stability of underground structures to prevent failure or collapse. A technique for the estimation of the full stress tensor based on acoustic emission (the Kaiser effect) is being developed and trialed at the WA School of Mines. The result obtained compare well with the standard over-coring method. The advantages of the technique are that it is relatively cheap, non-time consuming and is applicable to in situ stress measurements at depth in remote regions.

Jan 1, 2002

Experimental investigations were made into the decoppering of lead, tin, and bismuth using a technique which approximates on the small scale to industrial practice.Decoppering lead with sulphur alone in the absence of tin and silver did not proceed to low copper values. With a minimum of 0·02 per cent Ag or 0·10 per cent Sn, lead was decoppered to less than 0·01 per cent Cuby stirring with 0·2 per cent S over 10 min. Decoppering of tin or bismuth proceeded rapidly to very low levels in the absence of any "catalytic" impurities, at any rate in excess of those concentrations normally encountered in commercially pure tin or bismuth.

Jan 1, 1971

According to the data provided by the most recent European Survey on Working Conditions, roughly 25 per cent of the European working population is exposed to mechanical vibrations for no less than one quarter of the work shift duration, while around ten per cent are exposed for the entire work shift. The occupational exposure to whole-body vibration (WBV), in particular, represents a major health risk in mining, quarrying and civil excavation activities. In accordance with European Directive 2002/44/EC, the latest version of the Italian law on physical risks has recently confirmed the possibility of using relevant literature data on vibration magnitude in order to evaluate personal occupational exposure (vibration database or data provided by the manufacturer). Still the alternative option, based on field measurements, represents the most appropriated method of risk assessment, as it accounts for the actual operating condition at the workplace; actual operator and vehicle under investigation and specific working cycle. The article discusses the vibration measurements taken on a number of heavy machinery (excavators, loaders, trucks, dumpers, etc) employed for talc extraction in a mine located in Sardinia and the resulting personal exposure for the drivers. The assessment was carried out in accordance with the specifications of ISO 2631-1 and EN 14253.

Dec 6, 2010

By Y Yang

This paper discusses various issues surrounding the metallurgical control for furnaces, especially focusing on processes with long time-constants and æmetallurgical memoriesÆ. Examples will focus on furnaces accepting particulate and sometimes ill-defined feeds, eg submerged-arc furnaces, blast furnaces, secondary scrap smelting operations, recycling operations, waste incinerators, etc. Generally, because of the usually higher metallurgical time constant of these furnaces, these reactors have to be controlled in a feed-forward manner by the use of a hybrid of æblack boxÆ or empirical and ægrey boxÆ semi-empirical first principles metallurgical modelling and simulation techniques in a supervisory metallurgical control capacity.

Jan 1, 2000

By C Roche, G M. Mudd

The Morobe Province of central Papua New Guinea (PNG) has been mined for gold for nearly a century, although it is only in the past decade that large-scale modern mining commenced. The Hidden Valley gold-silver project began construction in mid-2006 and production by August 2009, and is located in the mountains above Wau in the headwaters of the Watut River. The mine is owned and operated by the Morobe Mining Joint Venture (MMJV), which also owns the Wafi-Golpu project, comprising the Wafi gold deposit and Golpu copper-gold deposit, situated in the Watut River Valley. Together they represent a potential mine of the scale of Ok Tedi or Bougainville or bigger. The MMJV is owned in equal shares by Newcrest Mining from Australia and Harmony Gold from South Africa. Although Hidden Valley was the first large-scale mine in PNG to engineer and build a tailings storage facility, poor environmental management during construction and early operations led to significant erosion of waste rock and sedimentation impacts throughout the ~200 km length of the Watut River. Since then, substantial efforts have been made to improve environmental management, especially waste rock placement and storage and water quality management. While the impacts from the Hidden Valley project appear to be reducing, the saga has heightened concerns by many along the Watut River and across PNG about ongoing impacts from mining.This paper presents the results of an ongoing project in the Morobe Province conducted by the Mineral Policy Institute examining the historical, current and future impacts of mining, including community views, social and environmental impacts and the monitoring and regulation of mining. Overall, there is a clear need to more fully integrate social and environmental issues into life-of-mine planning and go above and beyond regulatory requirements. In this way, some of the lessons learnt – by the community, MMJV and government – can be incorporated before, during and long after mining.CITATION:Mudd, G M and Roche, C, ?2014. Mining in Morobe, Papua New Guinea – impacts, assurance and self-determination, in Proceedings Life-of-Mine 2014 , pp 313–336 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

When Haematite Explorations Pty. Ltd. began prospecting for petroleum in 1960, there was only ill-defined geological evidence on the land bordering Bass Strait to support the belief that petroleum lay trapped in sedimentary formations beneath its shallow waters.A reconnaissance of the area, made in 1961 by the airborne magnetometer method, covered the waters and islands of the Strait and overlapped the Victorian and Tasmanian coasts. The survey indicated the presence of the Bass Basin (which is completely water-covered), assisted in outlining the Otway and Gippsland Basins, and showed that each basin contains sedimentary rocks over 10,000 ft thick. Information on the regional geology and minor volcanic activity was also obtained.Marine seismic surveys carried out from 1962 to 1965 defined these basins more accurately and showed the nature and structure of the thick sedimentary sections.Correlation of the seismic data with onshore wells identified the sediments as Tertiary and Mesozoic. Subdivisions of the former in all basins and the latter in the Otway Basin were made. These Tertiary and Mesozoic rocks are not seriously deformed and they have good prospects of containing petroleum.Possible structural and stratigraphic traps, recognized from the seismic record sections by petroleum geologists, are being tested by offshore drilling which began in 1964.

Jan 1, 1966

By D François-Bongarçon

After a review of the progresses made on the liberation factor theory since its inception by Gy (1982), a new and surprising result of great practical importance is presented: the liberation factor. First introduced simply as a number between 0 and 1, then shown to be the ratio of two variances, is now shown to be well approximated by the proportion of liberated mineral.CITATION:François-Bongarçon, D, 2017. Evolution of the concept of the liberation factor and a surprising new result, in Proceedings Eighth World Conference on Sampling and Blending , pp 307–310 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

THE flotation plant at Mount Lyell was erected, primarily, for the treatment of ore from the Lyell Comstock mine. These workings are situated over a mile in a direct line north of the North Mount Lyell mine, and are connected with the Reduction Work at Queenstown by a 2-ft. gauge steel tramway via the Queen River valley a distance of 7 miles. The property was purchased from the Mount Lyell Comstock Copper Co. After the disastrous fire in the North Mount Lyell mine in October, 1912, steps were immediately taken to make Lyell Comstock ore available for treatment, in order to relieve distress caused by any prolonged stoppage of work, and subsequently 13,032 tons of ore, averaging 3.38 %copper, 0.28 oz. silver, and 0.034 oz. gold; were smelted. When operations were resumed at the North Mount Lyell mine, it was evident that there was no economic advantage in smelting Lyell Comstock ore as compared with the higher value North Mount Lyell ore, which was also a better flux for the Mount Lyell pyrites, and that the future of the Lyell Comstock ore depended upon cheap mining and successful concentration of the ore. Therefore, extensive trenching and diamond-drilling was carried out, and a sufficiently large quantity of ore proved available for cheap extraction by open-cut methods. At the same time bulk tests by flotation were carried out at the Minerals Separation testing plant in Melbourne on different classes of ore from the Mount Lyell Comstock mine proper, followed by laboratory tests at Queenstown on all classes of ore available. All these tests demonstrated that the ore was amenable to the process, provided that it was ground finely enough. Plant erection was delayed by the general dislocation of business at the outbreak of war, but finally it became...

Jan 1, 1920

By Cooper R. J

The essential features of the zinc concentrate roasting installation at the Risdon Works by the Electrolytic Zinc Company of Australasia Ltd. are given.The problem of maintenance of ignition in down-draught zinc concentrate flash roasters is discussed, and a solution offered.A successful and economical method of using by-product oxygen for raising the roasting efficiency of hearth roasters is described. Three methods of utilizing oxygen for the same purpose in flash roasting are detailed, and their relative merit, considered.INTRODUCTIONThe zinc sulphide concentrate used at the Risdon Works is roasted autogenously for removal of sulphur in two hearth roasters, and four flash roasters. The hearth roasters are of modified Skinner type with eleven hearths. They were designed, and are used, for roasting mixtures of relatively low sulphide content. Their design and operation have been described elsewhere (Forster, 1949).The flash roasters are down-draughted furnaces with cross-section and rabbling equipment based on the hearth roaster design, and the process is similar to that developed by the Consolidated Mining and Smelting Company of Canada Ltd. (Cominco) at Trail, B.C. (Stimmel, Hannay, and McBean, 1936).These furnaces are 20 ft. in diameter. They have three drying hearths through which hot gas is drawn from the combustion chamber by the burner fan. The combustion chamber is 2'1 ft. high above the collecting hearth (27 ft. in No. 4 unit), and the discharge hearth below it is 6 ft. high, so that a large gas offtake is possible. Four rabble arms for each hearth are carried on a central column. Dried, ground concentrate, and the air for roasting it, are fed to a burner...

Jan 1, 1958

This paper briefly describes the shaft, including sinking, steel sets and their installation, shaft equipment and winders.INTRODUCTIONThe New Broken Hill Consolidated Ltd. Service Shaft is a vertical concrete-lined circular shaft, 20 ft. in diameter with -steel sets spaced at 12-ft. centres. The diameter of 20 ft. was established as the minimum that would enable the shaft both to house the proposed hoisting and service equipment and to satisfy ventilation requirements as a downcast airway. The 12-ft. set spacing was based on South African practice in similar types of shafts.The shaft extends from the surface to 28 ft. below No. 22 Level, a total depth of 3,194 ft. Sinking was commenced in September 1946, and equipping completed in January 1955. Initially the shaft was sunk and concrete-lined to a depth of 52 ft., using a stiff-legged crane and clam-shell grab for mucking. Operations were suspended at this depth to allow the installation of the steel sinking head-frame, winders and ancillary equipment.Sinking and concreting were recommenced after four months and continued to a depth of 1,035 ft. 6 in., where the shaft connected with a pilot opening. The concrete lining was poured as sinking progressed and was piped from the surface to this depth, after which all concrete was lowered in buckets and discharged through a distributor suspended in the shaft. A cycle of stripping to the pilot opening and concreting was continued until the shaft reached No. 22 Level. From this level the remaining 28 ft. was sunk full size. All plats were cut and concreted as sinking progressed.

Jan 1, 1957

By S E. Munro, P D. Munro

The commonly traded base metals concentrates of copper, lead, tin and zinc are sold by miners to custom smelters using contracts whose terms were generally established at the beginning of the 20th century or even earlier. Technical clauses in these concentrates for items such as payable metals and penalty elements do not reflect current realities of extractive metallurgical technologies and hygiene/environmental issues.It is an axiom that the miners and smelters have a symbiotic relationship. While the existing antique and arcane commercial arrangements serve the purpose of transferring money from the buyer to the seller, they are not likely to result in the industry achieving better overall technical and economic outcomes. By examining the cases for copper concentrates and zinc concentrates in particular, it will be shown that the practical application of these antiquated technical clauses does not drive the miners to produce the better quality concentrates that should be desired by the smelters. This is despite development of mineral beneficiation and hydrometallurgical technologies that would allow the miners to make better products.The adage that any extractive metallurgical problem in the smelter is cheaper to solve in the concentrator still generally holds.While nickel concentrates are only touched on lightly in this discussion because sales terms are more opaque than those for the other base metals, it is expected that the same conclusions will apply.CITATION:Munro, P D and Munro, S E, 2015. Base metals concentrate sales contracts – change Pavlov and the dog, in Proceedings MetPlant 2015, pp 46–60 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

Mr. BRADFORD said :-On assuming this chair, which has been occupied by so many gentlemen of conspicuous ability; my first words must be an expression of the gratitude I feel for the honour you have done me in electing me to be your President for this year.When considering the subject matter of this address to you to-night, quite frankly may it be stated that for a long time I was on the horns of a very great dilemma, for while I could discourse on the modern political trend in relation to our industries at great length, it appeared to me that this was not the place for such a discussion. Next I turned to a consideration of whether a discourse on the theory and practice of iron and steel would be of interest.I, however, banished this idea also from my mind, because it appeared to me that you have already had a surfeit of this on your visits of inspection to our local industries and I did not want in any way to be held responsible for the iron entering into your souls! I therefore propose, with your kind consideration, to address you on other subjects of common and vital interest to all.My first words and thoughts turn on the absolute necessity of eliminating waste in our methods. If we are to succeed in our...

Jan 1, 1926

Factors leading to the necessity for some individual testwork in solving most specific hydraulic transportation problems are listed and a description is given of a method used in determining critical flow conditions. An outline is given of the basic theory of the purpose of the testwork, and a means of applying test results for varied pipeline diamet.er and material conditions follows. Engineering and economic factors are applied to the solution of a specific hydraulic transportation problem and the use of the test results in plant practice is illustrated. The advantages of connecting pumps in series in centralised pumping stations rather than individually along the pipeline are stressed. Some notes are added on the future possibilities and economies of post pump injection of solids into high pressure pipelines.THE HYDRAULIC TRANSPORTATION OF SANDSAs well as all the classical variables involved in a pipeline installation, one must consider, when solids are to be transported, the effects of such variables as:(i) Proportion of solids in the pulp.(ii) The average specific gravity of the pulp.(iii) Specific gravity of the solid material.(iv) Solid particle average sizing and possibly shape.(v) Solids particle grading.(vi) Pipeline diameter for effects other than classically hydraulic.(vii) Pipeline material.(viii) Fluid viscosity.(ix) Pump characteristics.(x) Abrasive or corrosive properties of the pulp.Not surprisingly, the application of published data to the hydraulic transportation of a specific material is difficult if not well nigh impossible. Most hydraulic transportation investigations also involve economic and site factors vary...

Jan 1, 1959

By A J. Nick, I I. Townsend, J M. Schuler, J D. Smith, R P. Mueller, L Sibille, K Leucht, J J. Fox

The first steps for in situ resource utilisation (ISRU) on target bodies such as the Moon, Mars and near-Earth asteroids (NEA), and even comets, involve the same sequence of steps as in the terrestrial mining of resources. First exploration including prospecting must occur, and then the resource must be acquired through excavation methods if it is of value. Subsequently a load-haul-dump sequence of events occurs, followed by processing of the resource in an ISRU plant, to produce useful commodities.While these technologies and related supporting operations are mature in terrestrial applications, they will be different in space since the environment and indigenous materials are different than on Earth. In addition, the equipment must be highly automated, since for the majority of the production cycle time, there will be no humans present to assist or intervene. This space mining equipment must withstand a harsh environment which includes vacuum, radical temperature swing cycles, highly abrasive lofted dust, electrostatic effects, van der Waals forces effects, galactic cosmic radiation, solar particle events, high thermal gradients when spanning sunlight terminators, steep slopes into craters / lava tubes and cryogenic temperatures as low as 40 K in permanently shadowed regions. In addition the equipment must be tele-operated from Earth or a local base where the crew is sheltered. If the tele-operation occurs from Earth then significant communications latency effects mandate the use of autonomous control systems in the mining equipment. While this is an extremely challenging engineering design scenario, it is also an opportunity, since the technologies developed in this endeavour could be used in the next generations of terrestrial mining equipment, in order to mine deeper, safer, more economical and with a higher degree of flexibility. New space technologies could precipitate new mining solutions here on Earth.The NASA Kennedy Space Center (KSC) Swamp Works is an innovation environment and methodology, with associated laboratories that use lean development methods and creativity-enhancing processes to invent and develop new solutions for space exploration. This paper will discuss the Swamp Works approach to developing space mining and resource extraction systems and the vision of space development it serves. The ultimate goal of the Swamp Works is to expand human civilisation into the solar system via the use of local resources utilisation. By mining and using the local resources in situ, it is conceivable that one day the logistics supply train from Earth can be eliminated and Earth independence of a space-based community will be enabled.CITATION:Mueller, R P, Sibille, L, Leucht, K, Smith, J D, Townsend, I I, Nick, A J, Schuler, J M and Fox, J J, 2015. Swamp works – a new approach to develop space mining and resource extraction technologies at NASA’s Kennedy Space Center: prospecting, excavation, load, haul and dump for in situ resource utilisation, in Proceedings Third International Future Mining Conference, pp 297–304 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

By Camier R. J, Perry G. J

Extensive deposits of brown coal exist in the Gippsland Basin, primarily in the Latrobe Valley. The total quantities of economically winnable coal in this region of Victoria and in other smaller fields are large enough to adequately assure Victoria's future electricity needs and to also provide large quantities for alternative applications, including liquefaction. As a result of the recent conflict in the Middle East attention has again been focussed on the production of synthetic fuels from coal. There have been many investigations over the years into the production of oil from Victorian brown coal. The purpose of this paper is to summarise the scope, objectives and major findings of these studies, with the emphasis on the direct hydrogenation route for converting brown coal to oil. The principal alternative processes are carboniastion and hydrotreatment of the product tar, or gasification and Fischer Tropsch synthesis of liquids from the product gas. The attractions of Victorian brown coal which have encouraged these studies include: ò the vast reserves of Victorian brown coal and the favourable conditions for low cost mining, ò the high quality of the coal (low ash, sulphur and nitrogen contents), ò the high reactivity of the coal giving high yields of product in hydrogenation to liquid fuels, ò the extensive data base available on the resource and its characteristics, and ò the availability of a skilled workforce and extensive infrastructure in the Latrobe Region to support a major resource development project. These advantages have been partially offset by: ò the high moisture content of the brown coal and the cost of drying, and ò the priority previously given to electricity generation in the allocation of the brown coal resource.

Jan 1, 1992

Experimental results are presented for the anode overvoltage as a function of current density for different alumina concentrations in an alumina reduction cell. Voltage changes due to the electrolyte resistance and also the decomposition voltage, have been evaluated as a function of alumina concentration and anode current density. From these values of voltage, changes in the total cell voltage have been derived for changes in alumina concentration for different anode current densities. The results show that for each operating current density there exists a discrete alumina concentration that defines a minimum reduction cell voltage. Discussion is made about potential savings in power consumption when the alumina concentration is controlled.INTRODUCTIONThe standard procedure in the aluminium industry when analysing the cell-voltage required for the Hall-Heroult process for reduction of alumina, is to subdivide the total voltage into the following components (e.g. Pearson, 1955; Maritell, 1960).1. ohmic drop through busbars and joints2. ohmic drop through cathode lining3. ohmic drop through anode4. ohmic drop through electrolyte5. overvoltage at anode6. electrolytic decomposition voltage.(Overvoltages ,at the cathode are of negligible magnitude at all practical current densities.)It is understandable that the voltages assigned for each factor invariably differ for different workers...

Jan 1, 1965

The coalmining industry in most countries has, at various times, suddenly been confronted with a decrease in demand for coal. Readjustments made to reduce productive capacity to match the reduced demand for coal have often resulted in hardship to mineworkers, loss of capital investment to mineowners and loss of coal reserves. The consequences of the methods of readjustment adopted in the past have contributed to the low esteem in which coalmining has come to be regarded by a large section of the gel).eral public in many countries.Four sections of the coalmining industry, representing different periods of time, different countries, and different methods of industrial organisation have been examined:Great Britain and the U.S.A. during the inter war years, the post war European Coal and Steel Community, and post war Great Britain under the National Coal Board. An assessment has been made of the methods adopted in each case to reduce productive capacity to match a reduced demand for coal. Finally the fundamentals of the problem-as it affects the coalmining industry of any country-are considered, and possible solutions put forward.During the 1950's, surplus productive capacity was a problem in many coalmining countries, including Australia and New Zealand. As a rule no techniques are developed beforehand to solve problems introduced by a sudden decrease in demand for coal. The situation is usually tackled by a series of short term decisions based on expediency, which often in the long run only aggravate the problem.

Jan 1, 1961

By P B. Card

"The website www.economicevaluation.com.au, which had its origins at the Project Evaluation Conference 2009, provides a free way for industry professionals to teach themselves economic evaluation. At its core is a set of fast-moving modules and three worked examples.The website recognises that economic evaluation is a discipline with a hierarchy of three levels:decision-makingevaluating the project/businesshands-on modelling.There are a set of modules for each level that describe the concepts and activities in detail. These emphasise that the most important and rewarding work is the evaluation of Level 2. The economic model created in Level 3 is merely a working tool and should not become a sophisticated ‘trophy’ in Excel that only one or two people can comfortably use.Hands-on modelling contains three sets of practices designed to make any model rigorous and intuitive so that it can be easily understood and used by others in the project team. Even if the model develops into a long, detailed and complex workbook, it should remain easy to follow and be intuitive. The website advocates freedom to devise any architecture that best suits the project under study, but promotes rigour through the following practices:four cash streams and graphsthree architectures – concept, prefeasibility and feasibilitysix principles.The modules in the Level 2 evaluation use conversational language to describe in detail the broad range of activities needed to properly understand and characterise a project/business. It stresses that net present value is nothing more than the mathematical treatment of a whole set of opinions, is not an absolute truth and is only a fraction of the evaluation process. The modules describe in detail the range of economic metrics that should be computed and the full spectrum of equally important characterisations required to make the decision in Level 3.CITATION:Card, P B, 2016. Teach yourself economic evaluation, in Proceedings Project Evaluation 2016, pp 160–171 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 8, 2016

By Servant S

In the mine of this study, cemented hydraulic backfill is placed under the form of a slurry at a percentage of solid by weight varying from 50 to 65 per cent. This slurry settles and cures in the stope. During this process an important amount of water must be drained from the scope. Field observations in the case studied here show that the geometry of the drains system has a significant impact on the drainage of the stopes. The mode of filling produces a backfill showing an evident stratification typical of a sedimentation process. In situ observations on this material show that this stratification translates into a very strong heterogeneity in the physical properties of the cemented backfill. This heterogeneity should affect the hydraulic conductivity of the backfill in the scope. In order to study this aspect, finite element simulations were performed. This paper presents the results of these simulations, where the impact of this stratification on hydraulic conductivity is related to the performance of the backfill drainage system for various geometry. This preliminary study is aimed at providing a better understanding of the role of the drains in the dewatering process of the backfilled stope in the case of this Mine.

Jan 1, 1998

Variations in delay timing can have a marked influence on blasting effectiveness and, hence, on total production costs. In single-row bench blasts, delay firing is invariably more effective than simultaneous initiation. In single-row delayed blasts, there is an optimum inter-hole delay above and below which inferior blasting results are obtained. This optimum delay is equal to the time required for each charge to just effectively detach its quota of the burden. The inter-hole delay should seldom be less than 4 ms.m-l of burden.In multi-row blasts in which holes in a given effective row are fired on the same delay, the entire burden on any effective row should be detached from the rock mass just before charges in the next effeotive row detonate. Delays shorter than this give inferior blasting results and an increased likelihood of environmental and slope stability problems. If the inter-row delay is too long, cut-offs can occur, especially where the delay unit is located outside the blasthole. For a surface delay system, the optimum inter-row delay usually varies between 4 ms.m-l and 8 ms.m-l of effective burden. The number of rows that can be fired effectively with surface delay systems (in a single blast) is limited by the threat of cut-offs. Greater interrow delays and a larger number of rows per blast can be fired to advantage with down-the-hole delay systems.There are practical limits to the timing accuracy of all available delay systems. The existence of delay time variability should be recognized and duly considered in the design of blasts.The relationship between delay timing and blasting vibrations is not discussed.

Jan 1, 1977