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Developed and built in 1982 for simultaneous bathy-metric and reflectivity mapping of the deep ocean by the Hawaii Institute of Geophysics, SeaMARC II was a breakthrough in sea-floor mapping technology. The design was developed cooperatively by industry and academia, and the system has served as a prototype for a new generation of mapping tools for operation in both shallow and deep water.Research programs using the SeaMARC II system have focussed on basic research into the geophysical evo-lution of the Pacific, ranging from intra-atoll mapping to surveys of the deep-sea trenches. During the past few years most work has been concentrated on detailed investigations of the morphology of mid-ocean spread-ing centers, seamounts, and the subduction zones which surround the Pacific. The detail provided by the high resolution, 10-km wide side-scan sonar images of fault and fold structures, combined with the swath of bathy-metric information obtained simultaneously, allow previ-ously unattainable analysis of seafloor morphology and are leading to development of detailed models for ocean crust genesis and deformation.

Jan 1, 1990

By Cai S, Zhou C

The requirement of mineral resources is increasing as the economy is continually increasing in China. The mining practices of various complex sulphide deposits and precious metal deposits, and the treatment of mine tailings and other industrial solid wastes, have greatly improved fill quality in the metal mines. From early-1980s, high density slurry fill, paste fill of total tailings, low density slurry fill with addition of silicate gelling agent, etc has been studied and applied, and some progress has been achieved. Today, mine tailings, slag and power plant ash are widely used as fill materials in mining. A number of cemented fill mines equipped with large capacity trackless mining machines are in production. Recently, The 3rd Chinese National Symposium on Mining with Backfill, 1995 has been held, the progress of fill technology in mines has been exchanged and summarised. In the paper, some aspects of fill technology used in the metal mines of China are briefly introduced and some applications of fill research work are presented.

Jan 1, 1998

By LaBrooy SR

A number of gold processing plants in Western Australia have nickel in their ores, leading to significant levels of nickel on their loaded carbon. The presence of nickel during leaching, adsorption and elution'may have detrimental effects on cyanide consumption, carbon inventory requirements, stripping costs, electrowinning efficiencies and may contaminate the gold bullion.This paper discusses the competitive adsorption of gold and nickel cyanides onto activated carbon and investigates changes in solution parameters that may improve gold adsorption and/or inhibit nickel adsorotion.

Jan 1, 1997

By Espi J

The Nena high sulphidation deposit, located in the Sandaun Province, PNG, contains a measured and indicated resource of 51 Mt of copper ore grading 0.5% Cu and 0.6 g/t Au at a 0.5% Cu cut-off. The copper orebody is overlain by an 18Mt oxide gold resource grading 0.1 % Cu and 1.4 g/t Au at a 0.6 g/t Au cut-off. The deposit is hosted in advanced argillic altered pyroclastics interstratified with lavas, volcanoclastics, epiclastics and sediments of the Debom Volcanics within the Frieda River Intrusive Complex. Foraminiferal sediments indicate the Debom Volcanics to be Early-Middle Miocene in age. Alteration is elongated along, and concentric about a northwest trending structure (Nena Structural Corridor) which is about 7km in length. The inner two alteration types, residual and massive silica-alunite are strongly brecciated and host the bulk of later hypogene Cu-Au mineralisation. Weakly mineralised weak silica- alunite and barren peripherally zoned clay alteration surround the inner mineralised alterations. The hypogene sulphide deposition was polyphasal, episodic and is zoned from north to south from covellite-enargite ¦ chalcocite (5600N to 5200N) to a mixed enargite-luzonite (5200N to 4700N) to luzonite-stibioluzonite (4700N to 4400N) in the south within a 1200m long by 300m diameter sub horizontal pipe like body. Paragenesis studies indicate that pyrite ¦ marcasite were introduced early with barite and black native sulphur before deposition of banded pyrite (melnicovite) with barite during a period of brecciation. Continued brecciation allowed bladed covellite ¦ chalcocite followed by enargite-luzonite-stibioluzonite ¦ pyrite (brassy) and minor acicular covellite deposition. Yellow native sulphur and trace amounts of galena were deposited in remaining pores. Pre-acid alteration intrusives domed the mainly volcanic stratigraphy in the southwest and post-mineralisation porphyries in the northeast truncate mineralisation. Supergene processes and erosion have modified the top of the deposit, creating a 45m thick goethitic-scoroditic-haematitic gold cap above a 40m thick (on average) chalcocite rich supergene blanket. Lesser amounts of digenite, covellite native copper and rarely seen malachite occur in the supergene copper zone.

Jan 1, 1997

By Blackham M

West Wallsend No. 2 Colliery is a new mine that is presently being developed in the New- castle Coalfield by J. & A. Brown & Abermain Seaham Collieries Ltd., a subsidiary of Coal & Allied Industries Ltd. It is situated near Barnsley and is some 15 miles by rail from the port of Newcastle. The mine will produce coal from both Bore- hole and Young Wallsend seams. The Borehole seam has a working seam thickness varying from 7 ft to 5 ft while the Young Wallsend seam presents a choice of two distinct working thick- nesses, i.e. 5 ft. or 8 ft, the upper 3 ft containing much high ash material. The inter- seam interval varies from 10 ft on the western edge of the area to more than 70 ft in the central portion. The Borehole seam lies at a depth varying from 550 ft to 750 ft and the overlying surface terrain is gently undulating bushland with limited surface development.

Jan 1, 1972

By Roberts AW

Bulk materials handling operations depend on efficient storage and gravity flow facilit- ies. ,It is important that proper attention be given to the complete storage bin or stockpile and feeder combination. The paper briefly des- cribes the principles of efficient feeding and discusses the common types of feeders under practice. While ideally unaided gravity flow should be sought, occasions arise where flow promotion is necessary. Various types of flow promotion devices are described and their operational features evaluated.

Jan 1, 1978

By Marshall K. I

THE problem of satisfactorily eliminating the fumes and dust which are unavoidably produced in various metallurgical and manufacturing industries is one which has received considerable attention in the past, and has been the subject of much investigation and research. The solution of this problem was urgently desired for two reasons, the principal one being the fact that a considerable percentage of the total process losses in many industries was represented by the commercial values of the fumes and dust that escaped from the stack.The other reason is that, in some instances, the emission of the matter is regarded as objectionable. Various methods have been designed with a view to solving the problem thus presented, and the latest development that has beendesigned is the process of electrostatic precipitation. Continued investigational and developmental work with this process has already demonstrated its applicability to many industries, and new uses to which the process can be put are being opened up. Its use is already widespread, and the economic success that has attended its application in most instances would indicate that its use will become more general in the future.It has proved its ability to treat gases over wide ranges of temperature, and has successfully handled various types of fumes whose chemical characteristics differ very considerably. In many processes it has now come to be regarded as standard equipment.HISTORY OF ELECTRICAL PRECIPITATIONThe first recorded observations on the influence of an electrified insulated wire on gases containing solid particles in suspension was made as early as 1824 by Hohlfeld, in Leipzig. He found that, if he electrified a wire hung in a bottle filled with smoke, the smoke cleared rapidly, and a deposit formed on the sides and bottom of the bottle.

Jan 1, 1923

By Dobos SK

The Black Ridge Gold Deposit is located in the northern part of the Clermont Goldfield, which is situated at the boundary of the Bowen Basin and Anakie Inlier, Queensland. The goldfield comprises a series of NNW-trending semi-isolated basins, which are tectonically aligned with the Denison Trough, the west-most division of the Bowen Basin (Fig. 1-1).The main stratigraphic units in the deposits in younging sequence are the Anakie Metamorphics, the early Permian Blair Athol Coal Measures, the late Permian(?) White Section, and the Tertiary basalts which are regionally widespread, and intruded by abundant mafic and felsic plugs.

Jan 1, 1990

By Y Bissiri

The ever increasing demand for metals and minerals is putting significant pressure on current mining companies to find more ore. As these companies explore and mine, the future appears to be to go deeper and deeper underground. With depth, however, comes ever increasing costs as infrastructure such as hoisting, ventilation, the movement of workers and materials increase in size and scope. Further, the actual rock mass becomes prone to destruction through rock bursts and the heat generated becomes a major issue resulting in extreme expenditures in cooling plants and some of the biggest air movers in the world. All these issues result in dramatic changes in both capital and operating costs, subsequently making cut-off grades rise. As this trend continues there is an economic limit to how deep one can go, resulting therefore in a severe shortage of accessible ore deposits to mine. This paper discusses the need for larger marine robotics technology and presents the state-of-the-art in current research in underwater tele-autonomy, specifically the development of high bandwidth optical communication networks critical to any future activities (mining, construction, etc) underwater. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By A Creighton, C McKenzie

Blasting is a critical task in the development of an open pit. The formation of stable slopes is also essential to the safe and economic extraction of ore. The objectives of a mine blasting department are often considered to be in direct conflict with those of the geotechnical department. This should not be the case. Personnel in the various mining departments need to understand that their goals are the same û to optimise safety and cost-effectiveness of the operation. Blasting has the potential to damage rock that is to remain in situ by generating either excess vibration, and/or pressure. These damage mechanisms are described and guidelines with respect to blast design to minimise the potential for damage are given. A rock mass could be expected to be subjected to varying degrees of damage by blasting, including both intensity of damage and also the extent of damage. These issues have potential to impact significantly on geotechnical design considerations. It is therefore important for the practitioner to define what constitutes damage. In the context of mining, it is recognised that there is a need to balance the requirements for efficient excavation with those of forming stable and cost-effective pit walls. It is therefore important to have a set of key performance indicators (KPIs) against which the performance can be bench marked. These would include cost and time, both of which may be influenced by very diverse factors such as drilling, explosives and their performance, fragmentation, excavator and haul truck performance, requirements for batter clean-up and safe working practices. KPIs are identified and discussed in this paper.

Jan 1, 2003

By A D. Bugarski, G H. Schnakenberg Jr

An investigation was carried out at a US underground mine to characterise diesel aerosols and to asses the effects of various control technologies on the concentrations and properties of particulate matter and gases emitted by heavy-duty diesel-powered equipment. This study was dedicated to evaluating the impact on mine air quality of contemporary diesel particulate filter (DPF) systems installed on mining equipment. Additional efforts were made to assess the effect of blended biodiesel fuels, yellow grease and soy, ultra-low sulfur fuel, a fuel emulsion and of selected diesel oxidation catalysts on air quality and emissions. The carbon analysis performed on the collected samples showed that the tested DPF systems reduced the mass concentrations of elemental carbon in mine air by between 70 per cent and 92 per cent. In addition, TEOM measurements, collected during these tests, showed that the total diesel particulate matter concentration in the mine air was reduced by greater than 65 per cent when DPF systems were used. The tested biodiesel blends were found to reduce elemental carbon concentrations in the mine air by between 49 per cent and 33 per cent, for the B20 (20 per cent biodiesel/80 per cent #2 diesel) of soy and yellow grease respectively and between 66 per cent and 56 per cent for the B50 (50 per cent biodiesel/50 per cent #2 diesel) of soy and yellow grease, respectively. The water-in-diesel fuel emulsion was shown to reduce elemental carbon concentrations by as much as 85 per cent. NO2 measurements showed an increase in the maximum concentrations of NO2 when catalysed DPF systems were used instead of mufflers.

Jan 1, 2005

It is hypothesised that increasing the number of loading passes will produce a reduced range of truck payload outcomes compared with four-pass loading. The paper provides analysis to support this hypothesis. It is shown that, hypothetically, loading trucks with five or more passes will result in reduced tendency for overloading and reduced confidence interval for truck payloads that increase the confidence level of containing high end payloads within safe and commercially acceptable limits. Furthermore, increased number of passes provides for more precise bucket load spotting and so improves distribution of payloads within truck bodies. Truck-loading issues examined by the paper include: Improvement in life of driveline components and tyres. Generally tyre costs are relatively moderate; but tyres tend to become an increasingly sensitive performance/cost component as truck scale increases; Reduction of site severity fects flowing on to suspensions, truck frames and structural components generally with potential for reduced long-term repair costs; Less physical body damage due to smaller load increments; Reduced risk of non-compliance with payload limitations for safe braking standards; Increase in loading cycle times tend to increase with scale of loading machinery within the limits of a specific type of equipment (ie rope shovels or hydraulic shovels). Production increase with increased bucket capacity is, to a degree, offset by slower loading cycle times. This is particularly pronounced with front-end loaders but tends to be less noticeable with hydraulic excavators/shovels and electric rope shovels. Decrease in loading time, as a proportion of total truck-cycle time as open pits deepen and dump reaches increase. The production and cost benefits of four-pass loading tend to diminish as truck cycle times increase. The paper also discusses the implications for loading-equipment philosophy to satisfy the future needs of the industry. Cost benefits from upscaling tend to diminish as truck scale increases, so increasing management diligence and close monitoring are required to ensure that expected outcomes are realised. These truck-loading issues have been researched to assess the benefits positive or negative) of four-pass loading in practical scenarios. An attempt is made to determine whether four-pass loading is a æmust-haveÆ or merely a æmythÆ.

Jan 1, 2003

By A van As

This paper serves to outline the circumstances and causes of the air-blast that occurred at Northparkes Mines in November 1999. It describes the design of the mine, the geotechnical issues surrounding cave propagation and the cave monitoring systems that were in place prior to the event. A short description of the air-blast that followed a sudden collapse is given. Details of the risk assessment process that evolved during the rectification process are provided with their subsequent modification to form the core of a major hazard monitoring process. The system is in line with the recommendations given by the Coroner resulting from the inquest into the deaths of the four people who lost their lives during the air-blast.

Jan 1, 2005

By L Torckler, J Hobbins

Favona is a blind low-sulfidation epithermal vein deposit in the Waihi Vein System approximately two kilometres east of the world class Martha Hill deposit that has produced nearly 6.8 M oz Au to date. The Favona epithermal system has surface expression in variously altered and mineralised hydrothermal eruption breccias forming a series of low hills that are windows through post mineral dacites and ignimbrites. The tip line of the Favona vein is about 50 û 100 m below surface with a steeply east dipping principal vein structure carrying numerous hanging wall splays in the upper flatter section and thickening down dip where the vein steepens. Host rocks comprise feldspar phyric andesite flows with minor pyroclastics. Although Favona has a strike length in excess of 1000 m and vein widths up to 25 m over a vertical range in excess of 400 m it was only recently discovered after nearly thirty years of exploration by various companies involved in the Martha Hill joint venture that operates the Martha Mine. Since discovery in 2001 a feasibility study based on 27.5 km of diamond drilling in 83 holes has been completed reporting a reserve of 1 Mt @ 10 g/t Au against a resource of 1.8 Mt @ 10.3 g/t Au. Exploration is continuing with a further 20.5km of diamond drilling completed to date on nearby prospects.

Jan 1, 2004

By Dorricott M. G

Ballarat Goldfields NL is developing an exploration decline at Ballarat East using a Mitsui Miike S-125 roadheader. To-date, 530 in of advance has been achieved at an average rate of 16.1 m/week. Roadheader availability has averaged 94.3 per cent, and pick consumption has averaged 0.016 per m. Ground support has involved pattern rockbolting with split sets, 100 mm thick fibre reinforced shotcrete, and steel sets as required. The slower than expected advance rate has mainly been due to difficult ground conditions. It is expected that a further 970 in of decline will be mechanically excavated before a drill and blast system becomes more economical.

Jan 1, 1995

By Whiting AN

Major changes in the world in recent years are changing the criteria for selection of future developments. Oil prices soared during the 1970's while commodity prices including metals and minerals fell. Many new independent nations, have been created and now control the resources in areas which were once part of great colonial Empires.

Jan 1, 1983

By A K. Bayer

When the human eye fails in the evaluation of quality parameters in the extraction of minerals the use of laser-induced fluorescence analysis (LIF) can supply more detailed information on the composition of rocks. On the basis of measurements of selected raw materials engineering concepts for the use of this method in the mining industry as an innovative system for horizon control of mining machines will be described and the most important analysis parameters, influencing factors and interference variables are presented.

Jan 1, 2003

By P Warner

Mines are often located in remote areas that are not well served by æstiffÆ power grids. Radial transmission networks, high lightning incidence (eg in South Africa the Witwatersrand experiences seven to ten strikes/km2 per year), low short circuit strengths and diesel generation are not uncommon. All these factors result in the electric power supply to many mines being unusually prone to dips and disturbances. æLegacyÆ winder drives û cyclo converters and dc drives û convert power directly from the supply to the motor, with no intermediate energy storage element. Further, they rely on the supply network for commutation and are therefore sensitive to supply voltage disturbances. There is a high probability that a dc or cyclo mine winder will trip during a supply disturbance, often resulting in lost production time and call-outs for technical staff to reset or even repair equipment. In contrast, a voltage source inverter (VSI) ac drive stores a large quantity of energy (in the dc link capacitors) and is fully self-commutating. Hence, this topology is inherently more immune to supply voltage disturbances. Indeed, vendors of ac VSI mine winders make general statements about the superior performance of their drives during supply disturbances. However, the advantages have apparently not been previously quantified. This paper compares different winder drive topologies and their sensitivity to supply disturbances, considers categories of supply disturbances and quantifies the cost of the effects on the different drive types.

Jan 1, 2005

By Zharinov SE

Geonechanical modelling of island arc sys- tems and their analogs is investigated. Slow seismotectonic movements along the inclined deep fault zone under the compressive horizontal stress conditions are proposed to be the princi- pal mechanism controlling the structures and processes in the active continental margins. A model of shearing surface crack in an elastic half-plane is used for simulation. The main ele- ment of the model is viscous interaction bet- ween the crack sides, the viscosity varying with depth. To describe the stress-strain state of the medium an integro-differential singular equation is derived and solved numerically. The results of simulation are in good agreement with geological and geophysical data on the ac- tive continental margins.

Jan 1, 1987

By Restarick C, Jowett A

A cylinder-cyclone system, fitted with a flow control valve between the cylinder and cyclone plus in some tests a variable cyclone spigot, has been used to achieve classifier separations at unusually coarse sizes relative to the diameter of the units used. The method has proved to be useful for low tonnage flows at low pulp density and variable feed rate. The system relies on use of a cylinder unit to reject excess water and fine particles, the amount rejected being adjusted by the flow control valve. The valve also adjusts flow rate and pulp density of feed to the cyclone unit, and can be adjusted to give a separation at a coarse particle size. The system has been used in connection with experiments on the pilot plant at Mount Isa, where a 76 mm system was used to classify feed to the lead secondary rougher circuit at sizes as coarse as 52 micrametres galena equivalent for split conditioning tests. Further tests have been carried out with quartz to assess the range of size separations Possible.

Jan 1, 1978