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The Australian bulk explosives industry has matured significantly over the last five years and it would appear that the rest of the world is following suit. This maturity is characterised by the technical sophistication of modem bulk explosives, an increase in the technical competence of the explosives consumer and a greater openness in the debate on the quality and performance of explosives. The principal mechanism by which these advances have been made is undoubtedly commercial competition in the market place although a new element, technical competition between manufacturers and independent professionals, has and will continue to play an important role in the development of the industry. The relationship between the explosives manufacturer and consumer is necessarily both complementary and competitive. This paper identifies the need for the consumer to take a more prominent role in the critical analysis of the performance of explosives and to use his commercial influence to direct explosives manufacturers at least in the direction required for the future technical development of the industry.

Jan 1, 1990

By K Guilfoyle, A Robertson

In the mid-1970s, trucking ore from 400 m depth to the surface was perceived to be the practical and economic limit for metalliferous underground mines. Improvements in truck design and decline development resulted in the economic depth of haul exceeding 600 m by the mid-1990s. Today, mine operators and contractors are planning to use trucks for ore haulage from depths in excess of 1000 m. The authors of this paper estimate that there are in excess of 300 diesel-powered trucks operating in mines in Australia, and that by the year 2005 more than five per cent of these trucks will be æroad trainsÆ (ie trucks towing powered trailers or truck-trailer combinations). This paper examines the road train concept, presents cost and performance data and describes the advantages and disadvantages of the road train system as well as proposing the types of applications for use of road trains in Australian metalliferous underground mines. Truck performance is based on payload and average speed (expressed as tonnes x kilometres per engine hour (t km/h)). A road train with a powered trailer has a large payload capacity and two engines to provide a high ratio of power to gross weight. Thus it is possible to exceed 300 t km/h per cycle for an average haulage gradient of 1:9 compared to 250 t km/h for conventional articulated dump trucks (ADTs). It is likely that road trains in excess of 100 t capacity will have application for level ore haulage at large mines in Australia.

Jan 1, 2002

By R McConnochie, J V. Rowland, J L. Mauk

The Sovereign prospect in the lower Waitekauri Valley of the southern Hauraki Goldfield occurs in daciterhyolite flows and volcanic breccias of the Waipupu Formation. The lower Waitekauri Valley contains a series of NE to NNE-trending normal faults, and the Sovereign prospect lies in a NW-striking graben. The structure of the Sovereign prospect is complex. NE to NNE-trending veins and normal faults dominate the area, however WWNW and N to S-trending structures occur locally. Kinematic analysis of these structures indicates predominantly dip-slip movement, with a local strike-slip component. At least two sets of veins occur in the area: 1.        steeply dipping veins; and 2.       low angle veins, which cross-cut and locally offset the steeper dipping        vein set. Mineralization appears to have formed during normal faulting in an extensional regime.

Jan 1, 2007

In Munich's peculiar hydrogeological conditions (water bearing sand strata between layers of impermeable clay, silt or marl) are proper functioning groundwater lowering methods of decisive importance for underground construc- tion. Shield tunnelling with compressed air has al- ready proved to be successful. In view of growing application of shotcrete tunnelling it was obvious to consider the use of compressed air even here. After a preliminary research-project the first subway section "shotcrete under compressed air" was 1979 awarded in Munich and since that time five sections have been awarded, respectively completed. On the basis of the experiences meanwhile obtained reports will be given stating the frame conditions in which this new construction method can be applied. The tunnels consist of two shells. The outer ist driven by shotcrete under compressed air. In order to keep the air overpressure low, the groundwater often is previously detensioned or partially lowered. The inner shell of watertight concrete is built under atmosperic pressure.

Jan 1, 1987

By Laing W. P

Sedimentary structures are described from the WiIlyama Complex, New South Wales. Their presence confirms lithological layering within the metasediments as bedding. These primary structures occur not only in low grade rocks as previously reported by other workers, but also in areas of medium and high grade metamorphism.Sedimentary structures include graded beds, cross beds, ripple marks, and ball and pillow structures.The observed parallelism of the early schistosity and bedding in the Broken Hill area has previously led to the idea of transposition by isoclinal folding.In the areas mapped, small scale transposition is precluded on the basis of1. uniform facing of sedimentary structures over wide areas, and2. the existence of large areas in which the early schistosity is oblique to bedding.

Jan 1, 1975

By Reichman J, Chapman G

The features of seam gas drainage from the point of view of mathematical modelling are outlined and discussed: 1. The use of conventional single phase gas reservoir simulator for very simplified modelling. 2 Alteration of a conventional petroleum reservoir simulator into a specialised simulator for seam gas drainage. 3. Application. of a conventional petroleum reservoir simulator for modelling of seam gas drainage by the way of pseudo-functions and sacrifying one dimension.

Jan 1, 1982

By Arit I, Adisoma G

General Limit Equilibrium Method (GLE) and Janbu's Generalised Procedure of Slices (GPS) are two limit equilibrium methods in slope stability analysis which satisfy all equilibrium conditions. Numerical difficulties associated with these metho

Jan 1, 1998

By C Li

Removal of gangue minerals from ilmenite concentrates can beaccomplished by relatively low temperature roasting in controlled gasatmospheres to selectively enhance the magnetic separationcharacteristics of the ilmenite. At roasting temperatures below 800¦C the magnetising reactions are often not consistent with phase equilibria considerations. Metastable phases can nucleate and control the roasting products. In weathered ilmenites the phase assemblages and microstructures in the altered ilmenite grains can influence the roasting reactions. In this paper we give an overview of the phase chemistry of chemically weathered ilmenites and of metastable phases formed by low temperature roasting. We also report the results of roast experiments conducted in a neutral gas atmosphere. Major increases in magnetic properties after short roasting times at low temperatures were obtained for a range of ilmenite concentrates. For example heating a secondary ilmenite concentrate from Western Australia for 15 minutes in nitrogen at 600¦C gave an increase in the three kilogauss magnetic fraction from three to 92 wt per cent. The solid state phase changes accompanying the inert atmosphereroasts were characterised by combining elemental analyses withquantitative phase analyses of the ilmenite concentrates and their roast products. It was found that the phase reaction that is principally responsible for the increase in the magnetic properties of weathered ilmenites involves a transformation of disordered ferrous-containing pseudorutile to an ordered ilmenite-hematite solid solution containing typically ten to 35 mole per cent of the hematite component. Examples are given of the application of the inert atmosphere roast to effect separations of ilmenite from gangue minerals.

Jan 1, 2001

By Amelunxen R, Finch JA

Flotation columns represent an important addition to flotation practice. Columns have largely replaced. conventional machines in molybdenum cleaning in Canada. Columns have been successfully tested on bulk copper/molybdenum cleaning at Gibraltar Mines Ltd. A rougher cleaner/scavenger cleanercombination was shown to be capable of giving higher grades and recoveries compared with three stages of conventional cleaning. A control strategy for the columns has been developed. An interaction between gas hgldup and wash water rate has been exploited to control performance.

Jan 1, 1985

By Sorokin M. L, Komkov A. A

Flash smelting of nickel sulphide concentrate has been practiced at WMC's Kalgoorlie Nickel Smelter for 20 years. The mineralogy of the concentrate from the original mines was particularly suited to this process. However, taking a strategic view, potential new processing routes should be fully evaluated as possible replacements for the current technology. The Vanyukov process has been under development in Russia for the past 40 years and has been successfully applied on a large scale to the smelting of copper concentrates, at two locations - Norilsk and Balkhash. The potential for the application of the Vanyukov process to the smelting of nickel concentrates offers a number of processing advantages, including smaller reactor and decreased dependence on fuel oil. This paper reports on preliminary investigations into the application of the Vanyukov process to the smelting of nickel concentrates. At this stage the investigations are limited to semi-quantitative comparisons and modelling studies.

Jan 1, 1992

By Shining Z

The strength and deformation of more than two hundred coal samples have been tested in the condition of triaxial compression. The regression equation showing the relationship between coal strength and pressure in the pores, as well as confining pressure, was obtained. The appropriate calculation for stress-strain curve was carried out. Further, an analysis shows the variation of coal strength and its modulus of elasticity in methane medium.

Jan 1, 1992

By Poole GR

An unusually high flow of water from an oxtr.iction panel in Wongawilli Colliery pr,;npted the investigation of the possible sources of the water. It is more probable that water is derived f r,m sources adjacent to or within the Woo ' iwi 1 I i Coal rat her than by direct t r.onnuni n i"n from any surface source.

Jan 1, 1986

Mining companies around the world are seeking methods to coordinate operations between the mine and the concentrator to achieve an overall improvement in enterprise performance. In several instances very significant increases in productivity (more than 20 per cent) and profitability (more than $US 10M per annum) have resulted from such efforts. The key to realising these large benefits has for the most part arisen from improved communication between mining operations and plant operations personnel and the judicious use of new tools to evaluate alternatives for improvement and to minimise the risk of implementation. This paper presents a systematic approach to mine-to-mill optimisation . The importance of systemic thinking and systems optimisation methodologies is emphasised. New tools for evaluating operational performance are discussed. Recently reported benefits are summarised. Finally current research is discussed and projections for the future are given.

Jan 1, 2000

An Investigation on the Effect of Chrysotile Particle Shape and Anisotropic Properites on the Rheology of Chrysotile Suspensions Chrysotile, a polymorph of serpentine, is a phyllosilicate mineral that occurs as a major gangue mineral in many ores (eg Mt Keith nickel sulfide ore, Western Australia). The rheological behaviour of chrysotile stems from two main factors: its distinctive morphology and its electrical surface charge. It is believed that these factors are central to the problematic rheological behaviour and low solids throughput typically experienced in the processing of such ores. In this work, a study of the effects of chrysotile surface charge properties and particle shape on the rheology of chrysotile suspensions was conducted. It was found that the rheology of suspensions of pure chrysotile is characterised by extremely high yield stress values over a broad pH range (pH 4 to 11).The disparity in the point of zero charge and range of maximum yield stress for chrysotile is consistent with the anisotropic nature of chrysotile particles. A comparison of the rheological behaviour of quartz suspensions (non-fibrous) to that of chrysotile suspensions (fibrous) provides a practical indication of the effects of the fibrous nature of chrysotile relative to non-fibrous minerals. The long, thin fibres are easily entangled to form suspensions with much higher plastic viscosities and Bingham yield stresses than non-fibrous particles. Chrysotile particle shape and surface charge are central to the rheology of chrysotile suspensions, although shape appears to play a more significant role in this regard. This fundamental study would be beneficial to the ongoing research for improved recovery in the Mt Keith nickel sulfide ore as well as other chrysotile bearing ores.

Sep 13, 2010

By Yushan Ma, Jiqing Wang, Hanyi Jia

The Hedong Gold Mine is located in the Yantai area, Shandong province, China. It is an underground mine with an annual gold output of some 700 000 grams. The orebody is located on the edge of the Wanger Shan metamorphism zone, and the hangingwall of orebodies is thus defined by a prominent set of fractures. The proximity of the metamorphism zone and the inclusion of the fracture set ensure that both the orebody and the country rocks are unstable. The main orebodies dip at an angle of between 40 to 45¦, with a strike length of 160 metres and a horizontal width of 50 metres. Surface subsidence in the area is not permitted. Cut and fill mining is usually practiced. As the mining operation proceeds to greater depths, the ore grade is diminishing and it is necessary to find a more efficient stoping method. Sublevel open stoping with sequential extraction and filling of each sublevel has been designed and applied in situ. This new mining method is called æsublevel open and fill stoping methodÆ in the mine. Experience to-date is that new mining method is satisfactory.

Jan 1, 1998

By T Kang, V Sahajwalla, L Lu

During devolatilisation, physical behaviour of coals was investigated in horizontal electrically heated furnace with an inert gas atmosphere, and gasification rates of four coal chars and coke were measured thermogravimetrically in a carbon dioxide atmosphere at temperatures in the range 1100oC - 1500oC. The volume change of chars was also measured in horizontal electrically heated furnace at various temperatures. Both reactivity and the activation energy for the gasification of coal chars were found to be strongly influenced by pore structure and the carbonisation conditions employed during preparation. CO2 reactivity of chars increases with increasing reaction temperature, and particularly increases more rapidly over 1300¦C. CO2 reactivity of coke is lower than that of non-coking coal chars in the range of 1100¦C to 1500¦C. CO2 reactivity of chars with smaller pore area and bigger pore diameter is less than that of chars with bigger pore area and smaller pore diameter. During gasification, the volume of chars did not change significantly at the lower temperatures of 1100¦C and 1200¦C, but at the high temperatures, 1300¦C to 1500¦C, the volume of chars quickly decreased due to ash softening and melting. The CO2 reactivities of the chars are controlled by the mixed control of chemical reaction and pore diffusion in the temperature range 1100¦C to 1300¦C, and by bulk diffusion in the temperature range 1400¦C to 1500¦C.

Jan 1, 2000

By Campbell R

The use of a 35mm non-metric SLR camera and an analytical plotter to prepare close range photogrammetric (CRP) plans of a quarry and open pit mine face is described. The plans, at scales ranging from 1:5 -1:1 000, were used to measure the orientation of geological structures and failure surfaces in the exposed faces.Details are provided on the equipment used and the field techniques. The method:ò is quick and relatively cheap to perform,ò allows the accurate orientation of specific geological features to be determined,ò provides survey results of suitable accuracy that may be used for detailed geotechnical analyses of pit wall failures,ò shows great potential as a rapid and accurate technique for monitoring changes in pit wall profiles with time.

Jan 1, 1990

By Davison GR

The cost of drilling consumables is always a large component of any mine budget. It is important that this cost be carefully examined with a view to reducing the overall cost per inetre or at least minimising its escalation.At Renison it is considered that the only way to ensure drilling costs do not rise unduly is through a total system of control from purchase to disposal.In 1979 extension of an existing drill supply service contract was carefully examined and abandoned in favour of a hybrid system. This system is providing a great deal of control over the use of drilling consumables and has maintained a relatively constant cost per drilled metre over the last five years.Current consignment stock contracts for drilling consumables are strictly specified by the Technical Services section of the Mine Department and consumables purchased under these contracts are distributed and refurbished/sharpened by a contractor.The total result of this package is individual drilling items that achieve the best cost per metre and careful distribution and maintenance to ensure maximum life.

Jan 1, 1985

The Ida Valley in Central Otago is one of series of parallel basins filled with freshwater sediments. The basins are in fact tectonic depressions superimposed on NE trending grabenlike structures which occur in the area and are the result of block faulting possibly initiated in Cretaceous times and concluded in late Tertiary and early Quaternary. In Central Otago this tectonic event affected metamorphosed rocks belonging to the eastern facies of the New Zealand Geosyncline and collectively known as the Haast Schist Group. These rocks constitute the basement and the shoulders of the tectonic depressions. The Ida Valley occupies the depression wedged in between the Raggedy Range to the NW and the North Rough Ridge in the SE. The valley is approximately 38 km long, 3 to 7.5 km wide and is drained by the NE flowing Pool Burn, which meets the SW flowing Ida Burn. The resulting unified stream flows into the Manuherikia river which drains the next door depression to the NW. The present work deals with the Ida Valley basin and more specifically with the geology studied within two Prospecting Licence areas held by Gold Mines of NZ Ltd on the southeastern flank of the valley.

Jan 1, 1977

The comparison of belt drives with other types of power transmission involves the consideration of many factors before a final choice is made. Where other forms of power transmission might also be suitable, the selection of the correct type of belt has first to be made, in order to obtain a true comparison. The paper first deals with the types of belting available, followed by a description of most other forms of transmission equipment. An example is then given of the selection of suitable belts, which are then compared with other types of transmission. Comparative costs are also given. Reference charts provided show drives found suitable in general practice...

Jan 1, 1964