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By G Barla

In Europe, a major interest in the infrastructure and tunnelling fields is in the new crossings of Alps in the form of base tunnels, which are important components of the high-speed (for passengers)/high-capacity (for freight) Trans European railway corridors. These tunnels cross the mountain belt at the elevation of the main cities and basins located all around the Alps and are longer (up to 57 km) and deeper (up to 2500 m) than all tunnels constructed in the centuries before. The excavation of the first Alpine railway and road traffi c tunnels could in general be carried out successfully by conventional excavation methods. With the great lengths of the new base tunnels, mechanised excavation by using tunnel boring machines (TBMs) is imperative as it contributes significantly to savings in construction time and costs. Questions are however posed on the adoption of such a systematic tunnel construction method given the severe ground conditions which are some time anticipated along the tunnel alignment, with possible major geological hazards such as water inflow in heterogeneous fractured or karstifi ed rock masses, stress-induced tensile failure of hard rocks, and plastic shear failure and squeezing of weak rocks, etc. This lecture is to briefly review the current state-of-the-art in the understanding and modelling of two such critical hazards as spalling/bursting and squeezing ground behaviour. With the present interest in the design of mechanised tunnelling with TBMs in such conditions, the complex interaction between the rock mass, the tunnel machine and its system components, and the tunnel support is studied in detail by numerical modelling. The research and development efforts presently underway with the intention to provide the designer with a novel three-dimensional (3D) simulator of mechanised tunnel excavation are presented. Case examples are discussed with reference to the Lyon-Turin Base Tunnel design.

Mar 8, 2011

Samples weighing 0·5 g are fused with potassium hydrogen sulphate, leached with 4 ml. of 4 M nitric acid and diluted to 10 ml. with water. An aliquot of the clear solution is treated with EDTA, adjusted with ammonia to give a pH value between 5 and 6 treated with cyanide, ammonia, and sodium diethyldithiocarbamate then bismuth diethyldithiocarbamate is extracted with chloroform and the yellow colour is compared visually with a standard series. Alternatively, the bismuth complex may be filtered on a "Millipore" filter and subjected to x-ray fluorescence spectrometry.

Jan 1, 1971

By Collins L

The commercial success of a mining project can be strongly influenced by the business activity which takes place away from the mine site. The project revenue is determined by marketing success which results from persistent research and full realisation of suitable products and by-products and appropriate upgrading achieved in conjunction with proper material security and insurance. Significant costs of transport can be optimised, protection of the environment carefully managed and skilled employees acquired as a valuable asset. Working capital requirements are often substantial and should be carefully established and financed, possibly by special contractual arrangements for product sales.

Jan 1, 1997

It is no longer adequate when starting a new mine to simply select the best equipment. Today's competitive international commodity markets demand superior efficiency which requires systematic involvement of people in continual improvement of production and commercial processes. True Total Quality of Management (True TQM) principles provide an operating philosophy for maximising productivity and minimising unit costs of output. The presentation will show the practical and successful use of these principles. This paper will introduce the case study and provide background material on True TQM.

Jan 1, 1995

By L C. Thompson

This paper examines six sites in Northern Nevada where soils and groundwater have been contaminated with petroleum hydrocarbons and/or organochlorine compounds. All six of the sites studied are located in an arid, highly mineralised area of the Great Basin. As a part of the original geochemical investigation to determine the applicability of biodegradation in the remediation of petroleum impacted soils and aquifers extremely high levels of uranium, vanadium and molybdenum were detected in the anaerobic groundwaters associated with some of the hydrocarbon plumes. Some groundwater uranium concentrations exceeded 7 ppm while vanadium and molybdenum concentrations reached almost one ppm. The bioleaching appeared to be most effective under methanogenic conditions and was noted in both high sulfide and low sulfide environments. Background concentrations of uranium in the formation were measured between 6 ppm and 109 ppm and highly dependent upon depth with the highest levels being found in association with evaporites. Unlike uranium, vanadium tended to concentrate in free-floating organic fractions reaching levels as high as 2000 ppm in the layers of jet fuel floating above the groundwater. Molybdenum was the most resistant of the three metals to bioleaching.

Jan 1, 2004

By Bonsall EM, Schwabe MR, Hamlyn DA

Historically, most of the gold produced from Kalgoorlie has been derived from the gold and gold telluride Golden Mile lode systems dominantly hosted within the Golden Mile Doler-ite and to a lesser extent, Paringa Basalt. In more recent times the gold-quartz stockwork ore bodies within Unit 8 of the Golden Mile Dolerite at Mt Charlotte have become increasingly imp-ortant.Extensive low grade gold mineralisation has now been defined to the north and east of Kalgoorlie within rock units of the Golden Mile sequence not generally considered to be highly prospective.Two main types of mineralisation have been defined. The first comprises variably mineralised and altered quartz-albite porphyr-ies emplaced within talc-carbonated Hannans Lake Serpentinite (Mystery deposit). There is intense fuchsitic, pyritic and carbonate alter-ation of the serpentinite adjacent to the porphyry bodies. Gold mineralisation is assoc-iated with fine-grained disseminations and veinlets of pyrite and narrow quartz and quartz-tourmaline veining within the porphyry and adjacent fuchsite-carbonate rock. Several sets of vein directions are present, some of which typically exhibit sulphide alteration haloesnnA H] rhina_

Jan 1, 1984

By Bearman R. A

The majority of published material regarding the operation of crushing machinery is concerned with simulation of performance rather than design of equipment. The reason underlying the bias in published material relates to why research is carried out and who undertakes the research. Two distinct types of research can be identified: 1. Internal research by crusher manufacturers - generally related to mechanical design, value engineering and to the commercial realities attached to sales demands. Any work on basic crusher geometry or rock/machine interaction is of a sensitive nature and rarely enters the public domain. 2. Academic research - mostly confined to modelling of crusher performance and simulation. This is not because of any bias, but crusher design requires access to manufacturers data or at least an in-depth understanding of crusher design, which is rarely available. The crushing of rock is a complicated problem. It involves three aspects; the machine geometry, the material composition (type of rock/feed size distribution) and the machine/rock interaction. The machine geometry is often ignored in empirical mineral processing simulations, while the response of different feed materials is only nominally addressed in machine specifications provided by manufacturers. The manner by which the machine produces a stress field and causes different types of breakage for different rocks (or the machine/rock interaction) is sadly neglected by both groups. All three aspects must be considered collectively to successfully understand and model the entire crushing process. 1. Centre for Mining Technology and Equipment, Julius Kruttschnitt Mineral Research Centre, University of Queensland, Isles Road, Indooroopilly 4068 Qld. The importance of crushing is often underestimated. In mining and mineral processing the invisibility of the crushing process is understandable as it merely provides a coarse reduction stage prior to the intricacies of mineral extraction. However in the quarrying industry crushing and screening basically provide the finished product. A brief overview of the quarrying industry shows the importance of crushing. Figure 1 gives production figures for most of the western European countries, Australia and the USA.

Jan 1, 1995

By P B. Hills

This paper discusses the computerisation of the drill hole database, some historical records and the creation of a three-dimensional model of the gold bearing structures for resource estimation and mine design at the Beaconsfield Gold Mine in northern Tasmania. The phase of the work reported here commenced in November 1997 and was completed in March 1998. The historical mining on the Tasmania Reef had reached a depth of 450 m below surface when work ceased in 1914. Production up to this time was 854 000 ounces gold. Recent activity has concentrated on testing depth extensions of the previously mined ore structure, to a depth of 1000 m below surface, and the establishment of an underground mining operation to exploit this resource. The lode structure at Beaconsfield is a typical mesothermal vein style deposit. Gold is contained within narrow quartz, carbonate and minor sulphide reefs or veins. Reef width is variable from a few centimetres to several metres with æsplitsÆ or bifurcations being common. The reef averages 2.7 m true width in the economic zones. The key feature of this style of mineralisation is that reef continuity can be confirmed by drilling to a high level of confidence, but the gold grades are somewhat more erratic in nature. The resource estimates were based entirely on drill data. The drill intercepts on the reef were coded for each split directly into a database and these allocations validated graphically. The distribution of grades and widths show an increasing gold grade with reef width for both the drill hole and historical data. The same histogram patterns, mixed populations and overall arithmetic average grade for the historical mine (at 21.52 g/t > 3 g/t Au) and new drill data (at 21.55 g/t > 3 g/t Au) would indicate that there has been no major change in the overall style or grade of the ore from the historically mined areas to the new resource. The reef, host geology, area of historical workings and resource zones at the Beaconsfield Mine were defined as a series of closed wireframes. The Tasmania Reef was modelled as five mutually exclusive wireframes, one each for the Main Reef, Footwall split, Second footwall split, Third footwall split and Hangingwall split. The data for this exercise was extracted directly from the drill hole database, stored in Microsoft Access format. The formation of the solids was largely automated with manual validation and refinements allowing for multiple runs using different interpolation methods and combinations of drill holes. A rotated 3D-block model in the plane of the Tasmania Reef was created to contain the grade model and allow for tonnage, grade and reef width estimates. An inverse distance squared (ID2) interpolation method was used with ranges of 25 m along strike and 125 m down plunge with blank areas infilled with 50 m by 250 m. Each reef split was filled separately using only drill intercepts from that split. The method was independently validated used MIK methods. Longitudinal sections have been prepared showing gold grade, reef width and width +grade. Estimates were also made for arsenic, sulphur and other minor elements. The long sections show three distinct mining zones. A method is presented for the conversion of the resources to reserves by the addition of mining parameters for minimum mining width, minimum pillar, cut-off grade and internal and external dilution. The selection is done on columns within the block model, and allows for all splits to be considered at once. Multiple runs can be made for varying combinations of parameters to test different mining methods and their impact on reserves, mine life and NPV.

Jan 1, 1999

By Grant JR, McKavanagh BM, Dear SJ

A geophysical technique of rock mass assessment for engineering purposes is being investigated and shows positive correlation with direct structural logging and mapping techniques for the detection of major geological features. The technique is cross-hole acoustic surveying incorporating high speed signal averaging, with a maximum hole separation in excess of 30 metres in hard unfractured rock masses. The bulk of the field test work was carried out in open stopes in the copper ore bodies of Mount Isa Mines Limited. The investigation forms part of an integrated study of blasting in mining, aiming for fragmentation control through blast design modification. The rock quality factor, Q, is presented as a blasting index and can be determined for a significant portion of a production stope.

Jan 1, 1981

By Caelli T, Robey M

Most research into planning of open pit mines has been based on evaluation of volume-element block models in terms of their net present value. The major issues revolve around two interdependent problems the optimum ultimate pit and time-based scheduling. Despite feedback between the two problems, they are usually treated as separate tasks.The ultimate open pit is defined by the removal of whole blocks so that their net present value is maximised. This gives planners an estimate of the total worth of the venture in present terms, and is crucial to obtaining funding. All cost and profit values are assumed to be static throughout the mine life, and the only physical constraint usually taken into account is that of safe, average, wall slopes, which must be approximated by the removal of whole blocks. Modelling of any further constraints (for example, access roads and true wall slopes) is usually achieved by adding them to the optimal pit by hand. Typically this degrades the model by between five and 20 per cent of its value - which then brings into question whether it is still the true optimum.This paper reviews the dominant methods in use for this first task the ultimate open-pit planning problem. Some new optimisations are given, and the algorithms are examined in terms of their efficiency and accuracy. Finally, suggestions are made for improvement of model accuracy and eventual expansion into solutions of the more complete dual problem - that of simultaneously finding the optimum ultimate pits and dynamic schedules for the venture.

Jan 1, 1996

The treatment of the Broken Hill ores has,undergone many changes during the last ten years, and it may be of interest to some of the members to know what are the main lines on which the Proprietary Mine works at present. It must be understood that the want of absolute uniformity in the treatment amongst the various mines at the Barrier does not prove that some of the mines are working on wrong lines, for the ore is not exactly the same along the whole line of lode; this necessitates a variation in treatment, although generally only in detail.At the Proprietary Mine the ore is all mined by contract the miners are paid so much per ton for clean ore. The ore in the mine in most stopes is mixed with gangue, and the inclination of the uliners is, of course, to mix gangue with the ore, so as to be paid for as large 3 tonnage as possible. This is quite natural clean ore is easily distinguishable from clean gangue, but most lumps are a mixture of clean ore and gangue in varying proportions. The miner will naturally throw into his heap pieces which he considers still good enough, whilst the management may consider these pieces just a trifle too poor; consequently a check must be kept on this.This necessitates the first operation to which the ore is submitted. 'The trucks tare 51 cwt.; average load 21 cwt.), as they are loaded underground, have a ticket attached::showing to whiyh contract they belong on arrival at the top of the shaft they are passed over a weigh bridge...

Jan 1, 1907

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

The intention of this paper is to examine the practical and technical aspects associated with the measurement of blasting related phenomena. The emphasis is directed towards the acquisition of quantitative data rather than its theoretical interpretation. The application of advanced technologies will require that many more people involved with blasting become familiar with this topic. Against the many other disciplines where measurement may be beneficial, blasting is peculiar on several counts. 1) It must almost always be carried out in the field, and very often in a production environment. 2) Much consideration must be given for the safety of personnel and equipment. 3) The process is dynamic and seldom repeatable. Because the blast process is so dynamic there is little opportunity for direct examination. For this reason measurements are almost universally made using electronic techniques. In this way the event can be captured faithfully as it occurs and later examined in detail, after the fact. It is obvious that some familiarity with these electronic techniques is a necessary ingredient for successful blast monitoring.

Jan 1, 1990

The phenomenon of Instantaneous Outbursts, although not new to Australia, was sharply drawn to the attention of the local coal-mining industry by two isolated fatal occurrences on widely separated fields, both late in 1954. An outburst is the eruption of apparently solid coal from the face, aided by vast quantities of gas released from the coal, as the coal fails under mining stresses additional to its natural stressing.The gases involved are principally methane and carbon dioxide. The various factors which combine to produce outburst conditions range from external factors such as stresses arising from depth of cover and other causes, to inherent factors such as strength of coal,and its capacity to retain gases (sorption). Of the localities where instantaneous outbursts occur the Gard Basin in Southern France has had the greatest number and the most serious occurrences. By contrast, local outbursts have been minor.Experimental work into some influencing factors has been carried out by various overseas authorities and some research has been accomplished in Australia. Practices used in some overseas areas to improve safety of working are largely empirical, as are the local rules and recommendations for work in affected areas.The appearance of further outburst areas is anticipated as mining becomes more extensive and deeper.INTRODUCTION"Instantaneous Outbursts" can be described as violent eruptions of coal from the solid accompanied by considerable gas evolution. The projected coal is usually of small size, and a high proportion is pulverized, and may be carried and deposited over great distances by the gases, liberated from the outburst. This outburst coal is of bituminous to anthracitic rank, and the gas involved is essentially methane or carbon dioxide, or a mixture of both. Outbursts involving carbon dioxide are usually more violent and dangerous. The phenomenon is relatively unusual, being confined to probably sixteen known areas in the entire world, these areas comprising only portion of the coalfields in which they occur. Usually only one or two mines on each field are affected.

Jan 1, 1958

By Muller GP, van Deventer JSJ

A mineralogical analysis has shown that in the Hartebeesfontein ore studied, uranium is associated mainly with uraninite, sulphides such as pyrite and to a lesser degree carbonaceous material such as thucolite. Little could be learned from the literature regarding the mechanism of flotation of these uranium-bearing minerals. A wide variety of reagents were used so that conditions enhancing the flotation of either the sulphides, carbonaceous material, oxides like uraninite, or combinations thereof, were created. As could be expected, the xanthate based floats gave-better selective recovery of sulphides than oleic acid. A substantial fraction of the uranium is associated with pyrite, so that addition of oleic acid to a xanthate float did not enhance the recovery or grade of uranium. After a pre-leach with sulphuric acid in which the pH and Eh were controlled so as to destroy the uraninite, higher uranium recoveries were obtained for the combined float (xanthate, DTP and oleic) and the DTP float. This was most evident when iron was added before flotation. Roasting, which destroyed the sulphides and thucolite, caused a significant decrease in uranium recoveries. The uranium liberated in this way was obviously not flotable in the same way as the uranium liberated from uraninite. A small amount of iron (2 kg/t) added before milling resulted in slightly higher grades and recoveries of sulphur for xanthate based floats. Higher iron additions had a detrimental effect on sulphur recoveries. Even in the case of oleic acid the addition of small amounts of iron had a positive effect on the recovery of sulphur and uranium.

Jan 1, 1993

The economic significance of a fundamental understanding of the mineral pyrrhotite is dis- cussed. Particular emphasis is placed on the relationship of other sulphide minerals to the pyrrhotite when it is the major sulphide mineral present in an ore body. Studies of the Kambalda nickel deposit are used to give a better under- standing of (a) the genesis and other character- istics of a particular ore body (b) the textural relationships between pyrrhotite and other sul- phide minerals (c) magnetic properties of natural pyrrhotite, and (e) the oxidation and supergene processes that take place in a sulphide ore body.

Jan 1, 1972

In 1985 BMR assessed Australia's economic demonstrated resources of mineral sands as follows: rutile 8.0 Mt, ilmenite 41.4 Mt, zircon 11.5 Mt, and monazite 229 000 tonnes. These resources are located along the east coast of Australia, in the southwest corner of Western Australia, and in the Eneabba region, north of Perth, WA. However, over 40% of Australia's rutile and zircon resources, particularly those on the east coast, are presently not available for mining because of environmental considerations. As well, east coast ilmenite has been considered unsuitable for use by sulphate route pigment producers because of its relatively high chrome content. World demonstrated resources of rutile and zircon are estimated by BMR as 29 Mt and 38 Mt respectively. Demonstrated resources of ilmenite amount to about 1 billion tonnes. These occur predominantly in hard rock deposits in Norway, Canada, USSR and China, as well as alluvial deposits in Australia, South Africa and India. Quantitative data for world monazite resources is sparse. However, world production of rare earth oxides is now mainly from bastnaesite, a hard rock resource. Australia is presently the world's principal producer of rutile and zircon, and also provides a major share of the world's ilmenite. With the expected increase in Australia's rate of output of these commodities, combined with restrictions on mining along parts of the east coast, its position could diminish substantially over the next 25 years.

Jan 1, 1986

By Larsen D. F

Minor iron formation related base metal sulphide mineralization occurs in granulite facies metamorphic rocks of the early Proterozoic Willyama Complex. Rock sequences hosting three iron formation related Cu, Zn, Pb prospects from the Thackaringa Group (Suite 3) are described. A caparison of host rock sequences, style of mineralization and facies of iron formations suggests major differences in terms of the overall depositional environment. However, significant similarities are present with respect to the nature and distribution of iron formation facies and the occurrence of chlorite 'alteration' zones in close proximity to mineralization in all cases. The chlorite within these zones occurs in a number of diverse forms in a range of rock types. A comparison of the prospects shows that there is no evidence to indicate that the chlorite in the zones is a retrograde alteration product of former higher grade prograde mineralogies - the chlorite appears to have survived granulite facies metamorphism. The mode of occurence of the chlorite in the 'alteration' zones together with the fact that the association quartz + chlorite + magnetite + pyrite + base metals is cx rmn to all areas suggests that the chlorite is specifically related to the processes which deposited the stratiform iron formations and related sulphides. It is considered that the chlorite precursor was a prenetanorphic alteration product or chemical sediment closely related to submarine hot spring activity which was also the source for chemical sediment precursors of the iron formations, associated lode rocks and Sulphides.

Jan 1, 1983

By Hermulheim W

In the Federal Republic of Germany hard coal is mined underground only. The coal mines reach down to 1 500 m deep, recently having an average depth of 900 m. The commonly used winning system is long- wall mining with face lengths up to 250 in. The gate roads, which separate the seam into single panels, have an average length of one kilometre with a cross- section up to 20 m2. These single entries are usually supported by yielding steel arches. The installation of steel arches can hardly be mechanized. The choice of heavier support, caused by increasing depth and roadway cross-section, results in high cost for labour and material in gate roads. Furthermore, the heavy steel arch is acci- dent-prone, not only during installation but also during transportation and ship- ment. Rock bolts combined with a suitable lagging offer a way of mechanizing support work in headings. The aim is to decrease cost and to increase mine safety and pro- ductivity. Over the last ten years, 50 km of gate roads have been reinforced by a combination of rock bolts and weld mesh. Nevertheless, there are still differing opinions on the feasibility of rock bolting in gate roads. In Germany a long tradition and experience with steel arch support exists, whereas the function of an anchorage is a closed book to miners, preventing this new technique from spreading more quickly. Advantages and shortcomings of both steel arch support and rock bolting are compared. The experience with rock bolting up to now is reported. Possible improve- monts arm discussed.

Jan 1, 1986

Some attempt to minimise the importance of the greenhouse phenomenon. They do so by observing that global temperatures are still within the range of recent variations and that it is still not possible to predict with any certainty what the precise consequences of greenhouse will be. Both observations are true though the conclusion is dangerous. Ice core samples from the Antarctic and Greenland have established the composition of the atmosphere and global temperature over almost the last 200,000 years. The profile of these twin variables shows that they have moved together; when the concentration of CO2 has been up, the temperature has been up and when the former has been down the temperature has also been down. Over almost 200,000 years the CO2 content has ranged between lows of 190 ppm and highs of 270ppm. In just 200 years of industrialisation the CO2 content of the atmosphere has increased to 350 ppm, 50% higher that the mean of the last 200,000 years and 30% higher than at the start of the industrial age. Carbon dioxide is now increasing at 0.5% p.a. Methane, about twenty times more effective than CO2 as a greenhouse gas has doubled in concentration in the last two centuries and is now increasing at about 1.1% p.a. Methane, nitrous oxide, chlorofluorocarbons together with a number of lesser gases will double the greenhouse effect due to in creased CO2 over the next 40-50 years.

Jan 1, 1989