Search Documents

To help meet the challenge of mine finding at the start of the 21st century, the exploration geophysicist will have at his command a powerful range of tools, some new, some improved, and some which already exist today but are as yet little used. Remote sensing, using satellite and aircraft-based multi-spectral scanners, will provide the means for routinely mapping the surface distribution of certain carbonate rocks, clay and ferrous alteration minerals, based on the analysis of solar reflectance spectra. Time and emission-spectral resolved laser-induced fluorescence will likewise map the distribution of certain ore and pathfinder minerals, as well as certain skarn zones, all potentially related to ore deposits. The GPS (Global Positioning System), based on 18 orbitting satellites, will provide a universal, three dimensional, all weather navigation system which will completely supplant all existing aerial navigation systems, and greatly facilitate aerial surveying and automated processing and presentation of the data. Aeromagnetic gradiometer measurements will provide higher geometric resolution which will yield better definition of individual geological units. Multi-method ground geophysical surveys will be greatly expedited through the use of portable microcomputer-based, multi-sensor instruments. These instruments will interface with other intelligent devices for automated processing, presentation and interpretation of the ground field data. Borehole geophysics will come into more general use, both for at-hole measurements, especially using active nuclear techniques for grade determination, and for remote detection using a variety of electrical, magnetic, seismic and other methods.

Jan 1, 1986

In attempting to vegetate pnob!em sites some basic pn.i,ne%ptes, namely the phys.ica.e and chemi.ca2 pnope/ti;es og the problem mateni.al and the selection oU hu.itab.2e p!antts {cor pnopagati.on, have to be considered. Pnobtem sites such as tai ing dams, mined-out atteas, and areas which have been genehaUy advehse2y a46eeted by mining activities, are not only o~ten located in a divehs.ity o4 climatic regions, but they also usuaUy dL64en substantially in theAjt .int' Lns c phys.ica2 and chem.i cat pnopen t i.es . To estabP.ish vegetation on such sites 6requent2y requites: .%) The ame Lonaton oU adverse {yaetors in onde t to exeate a hoot env.utonment suitable Uon "satis1actony" plant growth. .%i) These.2eationo4 plant species suited to the improved Hoot env.utonment, and eompat%b&e with the e2imate o{y the site, and the ultimate Land use o4 the site. iii) The estabL shment o{y a Laboratory and p-LLot scale testing programme to aeeomptizh the above.

Jan 1, 1976

By Griffiths L, Marshall P

fhis paper describes investigations into drainage of gas from the solid to control outbursts. Initial studies conducted on drainage of shear zones showed that, given enough time, these can be successfully drained. Once drained, they can be intersected and driven through without any activity of outbursts. The results of programme of investigations to determine parameters for drainage from the solid show that gas flow rates from the Bulli Seam on the average are about 2 litres/min/metre length of borehole. But when shear zones are intersected, the flow rates could be as high as 8 litres/min/ metre length of hole. Shear zones can be picked up from pressure measurements 50 - 60 m away and this could give sufficient time to drill through these zones and drain them in advance. Systematic drainage of Bulli Seam at West Cliff Colliery could eliminate or reduce frequency of outbursts considerably. At present drainage holes are being drilled systematically in the seam, with drainage installations on the surface. Gas purity of 80% methane is being delivered at the surface plant.

Jan 1, 1980

The metals titanium and zirconium and their alloys occupy individually unique positions in the catalogue of metallic materials available for engineering applications. Because of the uniqueness of their usage in the aerospace industry, in the case of titanium, and in the nuclear industry, in the case of zirconium, the except- ional resistance of both the metals to the majority of corrosive media is often overlooked. The cost factor in the application of these more exotic metals has, in the past, been a major considerat- ion in the rejection of titanium and zirconium as constructional materials in areas of usage where their superior corrosion resistance strongly favoured them over more conventional metals and alloys. The cost differential, vis-a-vis austenitic stainless steels, for example, is not a trifling matter, being of the order of 6 : 1, when compared on a weight basis. However, if one considers the cost, for, say, sheet product on an area basis, the ratio is redgced to approximately 3.4:1. If one also takes into account the enhanced performance of the more expensive material and the sub- sequent increase in service life and decrease in plant down-time, the economics of the usage of materials such as titanium becomes much more attractive and, indeed, highly competitive,

Jan 1, 1969

The mining industry has a well deserved reputation earned over the years for innovation, engineering, management and the quick application to mining of emerging technology. The cumulative result is the economic exploitation of lower grade resources. The developments during the last decade have done nothing to tarnish the reputation. There are many that come easily to mind: the use of contractors for both surface and underground operations, a trend toward mine management contracts, the increasing recognition of the economic potential of ground support, and the development of physical measures to achieve it, - sophisticated measures to analyse blasting , and thus improve fragmentation, - instrumentation to assist geotechnical appraisal, - the development and application of the powerful and flexible, excavator, - the evolution of measures to improve grade control, - massive improvements in equipment productivity and reliability built largely around the application of hydraulics, - the development of powerful computer packages for orebody modelling, mine design and extraction, - simple "dense" fill systems, - maintenance management techniques including the greater use of off-site maintenance of exchange components, - the utilisation of communication systems for data transfer.

Jan 1, 1989

Workplace Centred Learning, (WCL), is a learning strategy which helps organisations cope with the constant change in skill requirements that is part of business today. WCL focusses on the specific needs of the workplace and provides the structure and sets the standard whereby the required competencies can be transferred between individuals. Learning is considered part of the job and ownership is achieved by involving individuals in all aspects of the learning system. Each individual in a WCL system is considered both a learner and a teacher. A significant advantage of WCL over conventional training systems is that it responds quickly to changing requirements, and once in place, becomes self-sustaining. That is, once implemented, the system provides mechanisms to detect and respond to changes in skill requirements as they arise. WCL is a competency-based system with multiple levels of validation. It provides a flexible approach to skills development that recognises both the needs of the workplace and the needs of the individual. WCL was developed in collaboration with ALCAN Aust Ltd and is currently being implemented by companies within Australia and overseas.

Jan 1, 1995

By J Walasiak

In the climate planning of mines and tunnelling with anticipated poor climatic conditions, and especially in case of longer working shifts, the main question is whether it can be reliably prevented that certain climatic limits laid down be exceeded. Working at high temperature and/or humidity can lead to reduced human working energy û a very important economic aspect û and to a risky lack of concentration on the part of the miners or to heat collapse and extremely dangerous heat stroke. With the Deutsche Montan Technologie GmbH (DMT) climate prediction programs, both the dry and the extremely significant humid heat transfer can be calculated. This is due to the high planning reliability involved. With the help of these climate prediction programs it is already possible to determine the anticipated climatic values for the operation phase as early as the planning stage of new ore or coal fields or of tunnel construction projects and to design the optimum air cooling system for every underground project with due regard to technical and economic aspects.

Jan 1, 2005

By Hebbard GJ

Vertical crater retreat mining is being used at Zinc Corporation, Limited and New Broken Hill Consolidated, Limited for pillar recovery between previously mined and filled stopes. In order to increase productivity in the older lead lode areas of the mine, particularly in the lower grade sections around the keel of the orebody, score form of longhole stoping was considered necessary.Due to poor ground conditions in the country rock surrounding the ore and the requirement to provide sane wall support during mining, primary VCR mining has been utilised in these areas.At Zinc Corporation, several stopes have thus far been mined by a hybrid longhole stripping - VCR method.

Jan 1, 1985

Indiscriminate surface disposal of coal waste in New South Wales has created a serious fire hazard and increased air pollution.A survey of numerous dumps, as well as particular investigations of one badly-constructed dump, showed that factors conducive to ignition and propagation of fires in waste dumps were high contents of combustible material (coal, pyrite, wood. paper. grease), size segregation leading to ready movement of air and moisture shape of the dump (e.g. protruding sections or porous junctions), high ambient air temperatures, bush fires, and even deliberate lighting.Control methods applied in the past tended to be haphazard and unsuccessful. Under Australian conditions the technique recommended for control of existing dump fires, based on experimental work, is to spray the dump with a chemical fire retardant (e.g. a 2 per cent solution of sodium tetra borate and ammonium phosphate), to cover the dump with a suitable soil, and to seal the surface with a I per cent solution of aluminium sulphate or sodium metasilicate. The recommended method of dump construction to prevent fires is to level and seal the site, to construct a firebreak around the dump area, and to build a rectangular dump with minimum size segregation and compacted surfaces.

Jan 1, 1971

White Cliffs Opal Field is situated in the Parish of Kirk, County of YulguIgra, New South Wales, about sixty miles from Wilcannia, and the River Darling. It is near the southern edge of the cretaceous basin of the interior of Queensland, New South Wales, and South Australia. Twelve miles south-west of the field, at Tarella station, a well sunk at the homestead reached silurian slates at about 127 feet, getting no water but about three miles north-west from the originally discovered and no central portion of the field, a well was sunk by the Momba, Pastoral cmpany, to a depth of 270 feet all the way through the cretaceous beds. At 250 feet a small supply of water was struck, but so much mineralised as to be quite useless. The temperature also was so high that a man could not keep his hand in it and Mr. Hogarth, the Momba Pastoral Company's manager, informs me that so corrosive was the action of the water, that a shovel left down the well for a fortnight, at the time of sinking, was completely eaten away.The well having now fallen in, I have been unable to obtain any of the water for analysis.The western termination of this portion of the cretaceous basin is situated about twenty miles from the present opal field, at which distance the slates, with (probably) devonian sandstones and quartzites resting unconformably thereon, commence to appear. The opal bearing country, as far as at present known, follows a more or less well defined line running north and south towards the northern end of the field, and north-east and south-west towards the southern extremity.

By P M. Larionov, V I. Zaikovskii

Transmission and scanning electron microscopy together with X-ray spectral microprobe analysis were used to investigate the structure and chemical composition of pathological calcified formations on the bioprostheses of heart valves. Controllable synthesis was carried out under the conditions (T = 37¦C, pH = 7.4) when the ion composition of the main elements (Ca, P, Mg and NaCl) is close to their concentrations in blood plasma. It is proposed on the basis of the obtained results that the formation of the hydroxyapatite of calcific inclusions on bioprostheses occurs as a result of spontaneous precipitation in the blood plasma. One of the factors determining the formation of massive calcified bodies on the bioprostheses of heart valves can be decreased magnesium concentration in blood.

Jan 1, 2008

Lithocaps are potentially voluminous zones of advanced argillic and associated argillic alteration located above the subvolcanic intrusive environment. They constitute exploration objectives for epithermal and porphyry-type deposits. High-sulphidation epithermal deposits may be sought within lithocaps, whereas low-sulphidation deposits may exist on their edges. Porphyry Cu-Au/Au deposits may be accessible beneath lithocaps if systems are telescoped sufficiently. Oxidation of the basal, pyritic parts of lithocaps may promote supergene sulphide enrichment under appropriate tectonic and climatic conditions.

Jan 1, 1995

By Lemberg D. W, Friday R. G

Potential means of lowering overall costs to permit deeper stripping include : 1. the use of larger diameter blastholes in highly-fissured strata (to reduce drilling costs); 2. dewatering from semi-permanent bores to reduce blasting costs (by maximising the use of bulk ANFO) and promote highwall stability; and 3. the use of inclined blastholes, bulk AN, staggered V1 patterns, adequate backfill and more cost-effective stemming columns. Each of these is covered. The pumping of bulk watergels continuously raises the blasthole water column, thereby perpetuating the demand for these blasting agents. This must be a principal consideration when choosing between a bulk and a packaged watergel. Any packaged product should exhibit dimensional permanence and an energy yield per metre length equal to that of bulk ANFO. Possible ways in which controlled trajectory blasting (CTB) could benefit deeper stripping operations are outlined. By allowing the maximum use of bulk ANFO, de- watering may be a prerequisite of a viable CTB Operation.

Jan 1, 1981

By S Moradi

The thickener overflow of zinc concentrate, obtained from flotation process in the Angouran plant located in Iran, contains a large quantity of slimes which were transferred to the tailing ponds. These slimes have caused problems of storing and environmental aspects in the Angouran area. The objective of this research is to describe the extraction of zinc from these slimes by leaching method using sulfuric acid in pilot plant scale.Chemical analyses showed that these tailing materials contain 35 per cent of zinc. By XRD analysis, smithsonite is identified as the major constituent. Calcite, dolomite, and cerussite are found as carbonate minerals. A minimal amount of Zn occurs as hemimorphite. Quartz, kaolinite, clinochlore and muscovite are other silicate minerals in the slimes.In the optimal conditions, ie acid leach at pH of 1, temperature of 55¦C, reaction time of 120 minutes and solid-liquid ratio of 1:3 and neutralisation with Ca(OH)2 at pH = 4.5, temperature = 70¦C, time = 90 minutes, the total recovery of zinc obtained was 95 per cent.

Jan 1, 2004

By Canning RG, Uusna S, Goodheart BA

The paper outlines the development of"a process for removal of iron oxides from ilmenite, thereby upgrading the TiO2 content of Western Australian ilmenites, from 55 to approximately 90 per cent. In the first stage, the iron oxides are reduced with solid carbon (coal) to metallic iron. Experimental reduc- tions were carried out in crucibles,, a fluidised bed and a small pilot plant rotary kiln. The reduced'ilmenite is,then agitated in aerated water, in the presence of catalysts, so that the iron "rusts" away from the ilmenite'grains and the precipitated iron oxide is easily separable by decantation. The influence of variables on the rates. of reduction and oxidation are discussed, The oxidation rate was exam- ined for both - the' physical oxygen-transfer characteristics and electrochemically by reference to Peurbaix diagrams, which plot redox potential against solution 'PH, The upgraded ilmenite is expected to be an attractive material. for pigment -manufacture,, and the iron oxide has prospects of being a marketable by-product. The process may possibly be. applied, to .other..ores.

Jan 1, 1964

By K S. Park, J K. Kim, J H. Park, Y Su

The present study investigates the possibility of the direct removal of oxygen from the Ti-30Ni (wt per cent) alloy melt through the thermodynamic equilibrium reactions at 1623 K in the vertical tube furnace. The deoxidation efficiency of Ti-Ni alloy melt by adding different contents of metallic calcium (Ca) as a deoxidant was evaluated with the binary CaF2-MgCl2 flux. The thermodynamic equilibrium experiments showed that the total oxygen content in the alloy decreased from about 650 ppm to 350 ppm when 3.5 wt per cent Ca was added to the Ti-30Ni (wt per cent) alloy. Alternatively, the effect of flux composition in the CaF2-MgCl2 flux on the oxygen content was also investigated at 1623 K. Therefore, the effect of binary flux systems on the deoxidation ability was compared at 1623 K. According to the results, the flux system with 80 per centCaF2– 20 per centMgCl2 exhibited the best deoxidation capability, ie total oxygen content in the alloy reduced from 1450 to 550 ppm.

Aug 21, 2024

The Yanacocha district hosts the largest and most significant acid-sulphate, high-sulphidation deposits in Per· with total production, reserves and resources of over 27 million ounces of gold. Several other smaller high-sulphidation systems are also recognised in the Cajamarca region including La Zanja, Sipßn, Tantahuatay, and San Nicolas. These each have reserves/resources of between 640 000 and 800 000 ounces of gold. Gold deposits in the Yanacocha district are hosted in an extensive volcanic field. Flow domes have intruded precursor pyroclastic rocks and flows that are interpreted as part of an earlier intermediate multi-vent volcanic complex. The larger, contiguous Yanacocha Norte - Sur and Encajon gold deposits are spatially associated with late-stage diatreme breccias. At La Zanja extensive acid-sulphate alteration is associated with the margins of the small San Pedro caldera (6 +4.5 km), nested within the larger, less well-defined La Zanja caldera (19 +24 km). The inner caldera is resurgent with abundant magmatism expressed as several flow dome complexes located on the caldera rim, and shallow level intrusive stocks. Gold mineralisation is associated with a WNW-trending structural corridor that transects the southern margin of the San Pedro caldera. On the eastern side of the La Zanja caldera there are a series of younger andesitic eruptive centres, some associated with acid-sulphate alteration and gold mineralisation. The Sipßn deposit occurs in one such centre with structurally-controlled gold associated with a NE-trending silicified structure developed within a sequence of andesitic tuffs. In conclusion, although a number of high-sulphidation deposits are recognised in northern Per·, their settings and styles of mineralisation are all quite different. Smaller deposits generally have strong and obvious structural controls. In the larger Yanacocha deposits the structural controls are less obvious, and mineralisation is disseminated in porous or strongly fractured and brecciated silica. Erosional levels are probably a significant factor, with disseminated mineralisation at higher levels, and structurally-controlled mineralisation in more deeply eroded deposits.

Jan 1, 1999

By M Yvon, S Parkes, K P. Galvin, P Wang

Mineral liberation is critical to maximise the grade and recovery of nickel, however this objective is challenged considerably by the poor flotation kinetics, especially that of ultrafine particles (Kelebek and Tukel, 2018; Multani and Waters, 2019). High recoveries demand long cell residence times and hence a large flotation capital expenditure (Wills and Finch, 2016). However, this leads to excessive entrainment of gangue minerals, thus negating efforts to depress its recovery. This study aimed to investigate new hydrodynamic approaches to improve nickel flotation, focusing primarily on unrecovered nickel from a Western Australian tailings stream. Mechanical cell flotation experiments were conducted to understand the flotation kinetics, covering different size ranges. A novel Reflux Flotation Cell (RFC) was also used to improve the nickel recovery and reject the silicates. Future work aimed at applying the RFC to different size portions is also outlined.

Aug 24, 2022

By M Schmid

German hard coal mining operations have decreased for more than 40 years. Current political decisions are leading to a discontinuation of subsidised black coal mining by the year 2018. This decision will, however, be reviewed once again in the year 2012. The enormous increases in productivity, which were achieved in previous years, have so far not led to an achievement of market requirements. Coal mining at depth of more than 1200 m in multiple seam environments is not yet competitive in global comparison. In 2008 the 24 faces left in eight mines produced about 20 million tonnes of usable steam coal. Management and the workforce will be reduced in parallel; from today until 2012 by more than half. The average age of personnel is increasing dramatically and nearly no new personnel are recruited. With this background in mind, increasing continuously coal mining productivity becomes more and more difficult. Above all, this goal was reached by mechanisation, then by increasing the mining machine power and then by enhanced machine control systems. The first attempts to automatically operate full face equipment from above ground were in the early 1980s. After successful automation of the face equipment, the emphasis is now on mine logistics. Autonomous monorail transport was introduced and tested in 2007. Since the development rate of machine improvements has its limits, the focus is on the full interaction of the total production system. Here information technology (IT) becomes important; the driver for more productivity. Actual developments aim for the complete and general homogeneous IT infrastructure both above ground as well as underground. The explosive environment needs high level investments in safe technology, eg access points for WLAN and fibre optics for underground use (ATEX certification). New technology availability also drives the enhancements of management and process control systems. Innovations in the mining industry often comprise technology advances through the adoption of well-known technologies. With virtual reality (VR) teaching and training systems advanced computational instruments, both in software and hardware development, were applied in the German coal mining industry for ten years. Widening lists of applications as well as the encouraging achievements show the economical benefits of investing in virtual reality technology both for teaching and training and for knowledge management. The paper discusses the actual technical achievements as well as in IT infrastructure utilisation and also in employment of virtual reality based systems. Special focus and deeper insight will be given to the fibre optics and WLAN hardware integration as well as software developments. The pocket personal computer (PC) is used to enhance underground material transport and data acquisition. The knowledge-based maintenance system (KBMS) integrates real-time virtual reality knowledge elements, such as repair process descriptions. It gives access to expert documentation by intelligent search algorithms and 3D representations of major mining machinery.

Jan 1, 2008

By Sen S. K, Banerjee D. D, Nandy D. K

It has been stressed that the intrinsic spon- taneous heating characteristics of a coal is not enough in predicting spontaneous fire risk of a mine. The influence of extraneous conditions created from the system of mining operations are also to be reckoned with, A case study was made with a mine in Jharia field, India, being proposed to be developed under short wall method with complete extraction in 4-5 slices followed by stowing.

Jan 1, 1988