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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

By Holliday RJ

The Imperial Smelting Furnace (ISF) was developed in Britain during the 1950's as a process which could produce zinc from a blast furnace. Since then it has evolved into an efficient means of producing zinc and lead from lower grade raw materials, both of primary and secondary origin. These changes have been in response to the need to improve the cost competitive position of the ISF in a climate of decreasing metal prices. The improvements at the Cockle Creek smelter of Sulphide Corporation Pty Limited have resulted from work undertaken in four main areas: 1. Changes in plant design and operating practice to give more stable furnace operation. 2. Improvements to the quality of sinter being charged to the furnace. 3. Improved monitoring of process variables and the formulation of control strategies based on the improved data. 4. Increased understanding of the processes occuring within the furnace shaft to allow predictive modelling to be undertaken. Work in these areas is still progressing but the work to date has resulted in a significant improvement in the production rate and efficiency of operation.

Jan 1, 1984

By Huafu L, Ruishi N, Hongnian Y, Qinglong Z, Yangshen S

The Dongshan terrane was first recognized in 1984 (Guo,et al., 1984, 1989) as an old continental crust block of migmatized granitic gneiss in the Southeast Coastal Hercynian-Indosinian orogen, and it was thought to have occured on Dongshan Island, which has an area of less than 100 km? Recent research work has shed much light on the geology of the Dongshan terrane.The Dongshan terrane is approximately 40-50 km wide and 380 km long, trending NE. It runs from the region of the mouth of the Ming River through Putian and Huian Counties, Amoy and Dongshan island of Fujian Province to Nanao island of Guangdong Province, bordering the southern segment of the coastal region and coastal islands of Fujian and eastern tip of Guangdong Province. The Dongshan terrane is divided from the Zhejian-Fujian Mesozoic Volcanic Mountain Chains by the Changle-Shaoan fractural zone, and its eastern boundary is covered under water in the Taiwan Straits.

Jan 1, 1990

The financing of mineral ventures is usually supported by the valuation of a mineral asset, the physical size and composition of which have been determined within quantified limits of accuracy in order that the lending or investment risk can be assessed. The Resource or Ore Reserve estimation is the measurement of that asset and may be the outcome of complicated processes of interpretation and estimation requiring an extensive knowledge and understanding of the general nature of ore occurrences, and of the particular deposit under review. In arriving at an interpretation of the nature and physical distribution of minerals in a deposit, observations may only be available from widely spaced samples and geological knowledge and principles are of prime importance. Consultants may be asked by the lending or investing body to "provide comfort" on the quality of the Resource or Reserve estimations and providing such comfort casts substantial obligations of diligence on the consultant.

Jan 1, 1990

By Gregory O, Winters BI, Garlick C, Rogers H, Ye ZC

BHP New Zealand Steel produces iron from titaniferous ironsand by a direct reduction process comprising multi- hearth furnaces/rotary kilns/electric iron melters. The electric iron melter is a six-in-line rectangular submerged-arc furnace which takes the partially reduced ironsand (80% metallization) from the rotary kiln and completes the reduction process to produce iron of nominally 3% carbon. As the melter operates at around 1500 ¦C and under very hostile conditions, it is near-impossible to obtain any basic operating parameters such as the velocity and temperature distribution in the slag and in the molten iron. As a first attempt to understand the operating conditions inside the melter, a scaled room-temperature model using wax and water to represent the slag and iron, was constructed. This paper will report on some of the preliminary model results on the temperature distribution.

Jan 1, 1995

The South Ghorveh Batholith (SGB) and the Almoughlagh Batholith (AB) intruded the volcanosedimentary sequence of Songhor Series (Triassic-Jurassic), during the Oligo-Miocene orogenic phase. The granitoids of the AB belong chiefly to the quartz-syenite and syenogranite clans while those constituting the SGB can be generally characterised as quartz monzonite varying towards quartz monzodiorite, and diorite. Granitoids constituting both the batholiths are low in free quartz, and possess characteristics of the æmagnetite seriesÆ, mostly of I-type, metaluminous to marginally peraluminous and calk-alkaline type. Adjacent to them are located the magnetite skarn deposits of Baba Ali and Gelali. In the light of petrography, geochemistry, mineralogy and field geology investigations they could be classified as Fe-skarn and mainly bear characteristics of calcic skarn deposits.

Jan 1, 2005

Beach sands on the Morobe coast of New Guinea contain significant amounts of chromite. This chromite, together with the more abundant associated minerals such as olivine, enstatite, tremolite, antigorite and feldspar has been de- rived from rocks of the Papuan Ultramafic Belt and transported to the beaches by three rivers, the Paiawa, the Saia and the Sesimbai. Of the hundreds of samples taken, 26 have been analysed mineralogically and chemically in some detail. On this basis, five groups of samples, four on- shore and one offshore, representing character- istic mineral assemblages, have been recognized. The chromite grains themselves have been exam- ined to determine variations in amount and in the Cr/Fe ratio, since this is of economic importance. Much of the chromite fails to reach a high Cr/Fe ratio as a result of magnetite rims around chromite grains. The precious metal content of the sands is negligible.

Jan 1, 1973

Brisbane based and listed on the ASX, Eastern Corp is pursuing the development of coal projects in New Zealand. There are various reasons why New Zealand coals are of interest û substantial resources, stable political/economic environment, close to Asian markets. In just over 12 months, Eastern has secured an operating coal mine (Cascade) and a prospective exploration area (Whareatea West), both on the Denniston plateau region, on the south islandÆs west coast. A key focus of activities is the development of relationships with key stakeholders and the promotion of the local economy.   Certain barriers may exist to the entrance by foreign companies into the New Zealand coal mining sector. These include geological challenges provided by the heavy faulting of the coals, port and rail infrastructure constraints, and the ægreenÆ factor.

Jan 1, 2005

By M W. I Visser Æt Hooft, R C. Schimmel

Until recently the Corus IJmuiden pellet plant produced approximately 4.5 Mtpa of pellets. Corus IJmuiden is currently running a program to increase its pig iron production to 6.4 million tonnes HM per annum. The burden of the Corus IJmuiden blast furnaces consists of approximately 50 per cent high basicity sinter and 50 per cent acid pellets, both produced in-house. To accommodate the increased pig iron production, the capacity of the pellet plant needed to be increased to 5.0 Mtpa. The productivity was increased by modifications to the plant layout, which were implemented during the 2006 cold maintenance stop. In addition, the composition of the ore blends is optimised to gain productivity.

Jan 1, 2007

By Fisher N. I

Disequilibrium ratios (U3O8/eU3O8), which assess the degree to which gamma activity represents the uranium content of a sample, have been measured on a representative set of samples from the ore zone of a carnotite ranium deposit located at Yeelirrie, Western Australia. A statistical analysis has been performed to investigate the dependence of the ratios on lithology and on the location of the sample in the orebody. The analysis indicates that dependence on lithology and on position across the orebody is negligible. Samples from the western end of the orebody and those from below the water table level tend to have slightly lower ratios than samples from other positions, although these trends are small compared with a large random variation in the data. The large random variation could result from some redistribution of the daughter isotopes of uranium within the orebody. On the basis of the results from all the samples, the estimated deficiency of uranium relative to radium in the ore zone of the deposit is 11 per cent.

Jan 1, 1980

By A Kyllo a, D R. Swinbourne

Electric arc furnace (EAF) dusts contain significant quantities of zinc, found almost entirely as either zinc oxide or zinc ferrite. The dust has been classified as a hazardous waste due to the relative high lead, cadmium and hexavalent chromium contents. It is important that environmentally acceptable processes be developed to treat this waste. One possible process involves reacting the zinc compounds in the dust with metallic iron, thus avoiding zinc vapour reoxidation by CO2 as occurs in carbon reduction processes. It consists of two stages where the first is the reduction of iron oxides to iron and the second the reduction of zinc oxide to zinc vapour by the iron. In this work the effects of operating variables such as temperature, CO/CO2 ratio and pressure on the recovery of zinc from an industrial EAF dust obtained from the Smorgon Steel Mill were investigated. Zinc recoveries in the second stage were found to approach 100 per cent at 1000oC after about four hours in nitrogen but within 40 minutes if a low vacuum was used.

Jan 1, 2000

The Mons Cupri Cu-Pb-Zn deposit is situated within a complex Archaean volcanic sequence dominated by rhyolitic fragmental rocks. This sequence is underlain by a 150 m group of rhyolitic ash flow tuffs with minor conglomerate and sandstone, and is overlain by approximately 180 m of dacite and andesite flows. The Mons Cupri sequence itself consists of several elongate or circular rhyolite domes, flanked by rhyolitic fragmental rocks ranging up to 400 m in thickness away from the domes. The lithology of clasts (typically 1 cm to 1.5 m in size) provides strong evidence that the flanking fragmental unit was derived by explosive eruptions associated with the rhyolite domes. An approximately 15 m thick shale horizon, bleached and silicified at its base, overlies both the rhyolite domes and the frag- mental unit. A south-dipping chloritic pipe-like body, with near-surface dimensions of 1,000 by 250 m and narrowing at depth to produce a cone-shaped cross section, lies within the rhyolitic frag- mental rocks about 250 m north of the largest rhyolite'dome in the Mons Cupri vicinity. Its east west elongation parallels that of the rhyolite dome. Ghost fragments indicate that the material in this fissure is a severely chloritized derivative of the rhyolitic frag- mental unit. The chloritic pipe is overlain

Jan 1, 1973

By S S. Kanchibotla, I Brunton

Most blast fragmentation models assume the rock mass properties, explosive properties and blast design variables to be constants and uniformly distributed within a blast. However, in reality all these input variables vary within a blast resulting in variation in the resulting fragmentation size distribution. A stochastic modelling approach is introduced in this paper to quantify this variation. This technique takes the input variables as statistical distributions rather than constants and through several thousand iterations, generates a statistical representation of the expected fragmentation resulting from a production blast. A case study of three production blasts from a large open pit mine are presented and the modelled fragmentation æenvelopeÆ shows good agreement with the fragmentation æenvelopeÆ estimated from Split image analysis. The various blast-related parameters influence different parts of the fragmentation distribution, eg rock strength and explosive velocity of detonation have most impact on the fines. The technique is used to identify the parameters that have the greatest influence on various size fractions. Such an analysis will be useful to direct resources to efficiently minimise the variation.

Jan 1, 2001

This report chronicles the historical development of longwall mining in the United States and speculates on future developments to the turn of the century. Five eras of technological development during the modern period are described and analyzed. These eras discuss the development of (1) mechanized extraction, (2) self advancing roof supports, (3) high capacity roof supports, (4) shield supports, and (5) system automation. Current trends are analyzed in terms of: longwall utilization, production capability, support capacity, face widths, and new technological developments. From these analyses, the future of longwall mining to the year 2000 is speculated. It is concluded that longwall mining will continue to grow in importance during the next decade and that the next major technological milestone will be the realization of a fully automated longwall mining system.

Jan 1, 1992

By Burks WG, Hughes FE, Muceniekas E, Whitcher IG

The area containing the iron field, recognised by the writers, is part of an uplifted, portion of the 'Western Australian Plateau,' ranging in elevation from about 1,000 feet to about 3000 feet above sea level. The local rock succession is flat-lying or moderately-folded and belongs to the Nullagine Series of Upper (2). Precambrian age. This series forms the Hamersley Rangeland vast portions of the...

Jan 1, 1964

Hydrocyclones are widely used in both mining and various industrial sectors. Considerable fundamental research work on the modelling of hydrocyclone classifiers has been carried out through the past 25 years. Based on the similarity principle, the hydrocyclone classification was taken as a whole physical process and a group of similarity numbers were obtained with the help of dimensional analysis in this paper. Then, the functional dependences of the similarity numbers have been established. The variables optimisation was carried out with the multiple objectives linear planning programs developed in this study.

Jan 1, 1993

By Phelan JM

Poor selectivity in the separation of two sulphides generally arises because the flotation characteristics of the coarse sizes of the valuable mineral and finer sizes of non-valuable minerals are identical. Separat- ing the pulp into two size fractions at a specifically determined cut size and conditioning each size fraction with its own optimum reagent addi- tion is known to be helpful in improving such selectivity problems. The performance of the zinc section of the complex ore circuit at Wood- lawn Mines has been analysed in detail. The selective recovery of zinc was found to be a problem in zinc/pyrite separation. However, atypi- cally, the separation problem was between coarse zinc and coarse, not finer, pyrite. In spite of this the use of separate conditioning has effected significant improvements in rougher concentrate. Selectivity (and hence grade), overall recovery and flotation rate have all been enhanced. Dis- appointingly, coarse zinc recovery was not increased but, with careful optimization, this might be achieved without sacrificing the gains already realized. The technique of separate conditioning clearly has general application in other circuits where selectivity is a significant problem.

Jan 1, 1988

By Trudinger JP

Mt. Newman Mining Company Pty. Ltd.3 oper ates the Mt. Whaleback iron ore mine in the Ham- ersley Iron Ore Province of Western Australia. The present rate of production of high grade hematite iron ore is 33 million tonnes per year. Mining is by open cut quarrying,with 15m high benches. The present quarry operations will be extended to a large oval pit to win over 1400 million tonnes of iron ore. The pit slopes will extend up to 500m in depth and the perimet- er of the slopes will exceed 15km. Sixty per- cent of the ore is below the water table, which presently lies 45m below the general plain level Dames & Moore, rock mechanics consultants designed the pit slopes during early mine devel- opment to ensure an economic and safe operation.

Jan 1, 1975

By B Rohrlach, J Gonzalez, A Buenavista

Located on the island of Mindanao in the Southern Philippines, the Tampakan copper-gold deposit represents a major high-sulfidation epithermal deposit superimposed on an underlying porphyry copper system. With a recent JORC compliant indicated and inferred resource estimate of 1104 million tonnes at 0.65 per cent copper and 0.26 g/t gold at a 0.3 per cent copper cut-off grade, Tampakan represents the largest undeveloped copper-gold deposit in Southeast Asia. Since its acquisition by Indophil ResourcesÆ affiliate Sagittarius Mines Inc in August 2002, the deposit is the subject of an ongoing preliminary feasibility study into project viability that is initially focused on a higher-grade copper zone in the north-central part of the deposit. The deposit is hosted by a sequence of subaerial andesitic flows (Tampakan Andesite Sequence) related to a highly eroded andesitic stratavolcanic complex of Pliocene age. Detailed mapping and geochronological dating has identified four volcanic cycles or centres that have been sequentially developed and eroded. This stratovolcanic complex is interpreted to lie on the northern extension of the Sangihe volcanic arc that extends from Northern Sulawesi in Indonesia. The Tampakan district is located within a complex tectonic setting dominated by WNW trending wrench faults that form part of the trans-Mindanao Cotabato Fault Zone. The Tampakan deposit is located near the intersection of one of several WNW trending splay structures with a prominent NNE trending dilational structure, one of many that transect the host volcanic complex. High-sulfidation style copper-gold mineralisation at Tampakan is broadly associated with and central to a flat-lying tabular body of pervasive silica and silica-clay alteration developed within a district- scale lithocap of advanced-argillic and argillic hydrothermal alteration that extends over an area of 90 km2 within the volcanic complex.

Jan 1, 2004

By Ibaragi K

High grade ores were intersected in 1981 by a scout drill carried out by the Metal Mining Agency of Japan during a reconnaissance dril ling programme. The original aim of the hole was to explore a deep target where geophysical anczralies overlapped the abandoned old drifts (gravity- high, resistivity-low by airborne EM, and resistivity-low near the surface and high at depth by Schlumberger deep sounding). Subsequently, a follow-up drilling programm was commenced by the Sumitcrro Metal Mining Co Ltd, and all the 18 holes intersected high grade ores. The resources were then "guestimated" to contain ca.120 tonnes gold with an average grade of 80g/t Au between -40m and +120n a.s.l. The underground development was started in December 1982 and the first crosscut intersected the ore body at 100m level (a.s.l.) in July 1985.

Jan 1, 1987