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By Miyashita T, Yamamoto R, Kishimoto s

Following considerations of the effect of furnace size on pressure loss, pressure loss in front of tuyeres, gas flow in the lower parts of the furnace, the distribution of the burden and the gas flow in large blast furnaces is examined with particular reference to the burden distribution at the throat and the gas flow at high production rates. Improvement of gas flow is related to application of super-high top pressure and the use of moveable armour. A brief description of the NKK type moveable armour is given and its use in controlling the gas flow outlined. The operating results under controlled gas flow show an increase in production of Fukuyama No. 5 BF from 9,200 tpd to 11,000 tpd with a decrease in the fuel rate from 490 kg/thm to 460 kg/thm.

Jan 1, 1975

BHP Minerals Ltd operates an open cut iron ore mining operation on Koolan Island, off the coast north of Derby in the Kimberley region of Western Australia. The mine comprises a number of pits, the largest of which is situated adjacent to the coast on the southern side of the island. The lowest bench is currently at RL +2 m, and the mine has planned ultimate depth of RL -82 m. Mining has already extended below the pre-existing water table level, and below mean sea level. In 1984, an extensive program of drilling, geophysics and test pumping was instigated to evaluate the aquifer hydraulic properties and the nature of the groundwater flow regime. With the aid of computer modelling, predictions have been made of the likely dewatering and depressurization requirements, and a conceptual pumping and drainage system has been designed.

Jan 1, 1986

Copper grades of diamond drill hole and development samples are determined in the core shed logging area at Mount Isa Mine using a Bulk Mineral Analyser. All geological and grade data on the copper orebodies is collected and stored on computer file.The raw data can be manipulated interactively using a computer terminal or by input of forms to produce output as computer plots or printouts. Grade distribution of copper or cobalt is obtained by the geologist using a computer kriging package followed by grade contouring. Computer plotted cross-sections and plans of individual stopes or several stopes can be produced showing geological structures, kriged grades at points and as grade contours.

Jan 1, 1985

1880 - 1930 - The Golden Years of Mineral Processing Technology

Sep 13, 2010

The Antarctic Peninsula consists of accretion complex sedimentary and volcanic rocks, talc-alkaline magmatic are rocks, marginal basin sediments and extension-related alkali basalts, dominantly of Mesozoic to Cenozoic age. Metallic minerals have been recorded at "250 localities but two thirds of these are innocuous occurrences of Fe+Cu accessory minerals. The remaining -70 localities are related to hydrothermal mineralization processes. Metallogenetic associations identified are: vein and breccia-hosted Fe+Cu+Zn+Pb+Mo or Fe+Cu+Mo+Mn, shear-hosted Fe+Cu, volcanogenic Fe+Cu and pegmatite-hosted Fe+Cu+Mo+Mn. Anomalous Au, Ag, As, W and Sb also occur but are not of economic interest. Metallogenic zoning is unproven and genetic models are uncertain, possibly involving volcanogenic, epithermal to hypothermal vein and porphyry-type systems. Substantial field and laboratory studies are required to understand distribution and Genesis.

Jan 1, 1987

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

By Will D. P

A 328 m, 2.4 m diameter raise-bored shaft has been equipped with a modular ladderway system to provide a second means of egress from Aberfoyle's Hellyer Mine in Tasmania. The modular ladderway consists of platforms, ladders and service pipes assembled at the surface and progressively lowered down the shaft. This system provides a rapid, safe and economical non-entry approach to equipping a shaft. The modular construction and single suspension allows for future extension or for reuse in another shaft.

Jan 1, 1988

By Woodcock JT, La Broody SR

As part of a project on the application of thiourea leaching to a variety of Australian ores, the systematic variation of pH, redox po- tential, and thiourea concentration were in- vestigated on an oxidized gold ore from the Nevoria mine, WA. Stirred open beaker tests were conducted with a pH-stat and Eh-stat system to automati- cally control pH and redox potential at selected values, while thiourea concentration was main- tained manually. Increasing the acidity of the leach liquor from pH 3.6 to pH 1, increased the gold extrac- tion from 37 per cent to over 90 per cent in S h, but there was only a limited improvement below pH 1.5. Silver extraction and thiourea consumption increased as the acidity was in- creased. Increasing the redox potential from 150 to 200 mV (i.e. potential of Pt electrode vs SCE) increased the initial rate of gold and silver extraction, but the effect on cumulative gold extraction by 5 h was slight. Thiourea consump- tion was greatly increased as the redox poten- tial was increased. An increase in thiourea concentration from 1.2 to 4.8 per cent increased the initial rates of gold and silver extraction, but, as for the change in Eh, the improvement in cumulative ex- traction by 5 h was marginal. Thiourea consump- tion increased with thiourea concentration.

Jan 1, 1984

By Dyne GD

From experience in the design and operation of power station combustion facilities in most mainland Australian States, involving a wide range of black coals and lignites, and in the specification and procurement of coal supplies for power station use, techniques for the optimisation of coal resource development and power generation utilisation have been developed to ensure compatibility between characteristics of the selected coals and power station design. These techniques include computer data bases for resource data handling and computer simulation of coal-fired boilers for determining coal property cost effects. Data Base Systems allow results of coal analyses to be efficiently handled, to assist in the review of the relevance of resource data to the coal sections proposed to be mined and the coal fractions proposed to be marketed. Data Base Systems also facilitate the marshalling of coal quality data into basic utilisation format to enable a proper utilisation review and analysis of the certainty and scatter of coal properties. Computer simulation of the effects of different coal properties on the capital and operating cost of power stations is achieved by establishing conceptual design parameters of the major items of plant to relate the variations in coal specification to equipment size and type. Variations in power station budget costs can then be determined using the computer model for variations in coal specification.

Jan 1, 1983

This paper will describe the exploration project which led to the discovery of the La Escondida porphyry copper deposit in northern Chile and will serve as companion paper to the description of the geology of Escondida being presented by J M Ojeda. The author would like to express his appreciation to Robert Hickman, Chairman of Minera Escondida, for permission to present this paper.In July 1978, a proposal was made by J D Lowell to Robert Wheaton, then Exploration Manager of Utah International, that Utah fund a "grass roots" program exploring for porphyry copper deposits in northern Chile. Wheaton expressed interest, and it was agreed that Getty Oil Co also be invited to participate. A joint venture agreement for the Atacama Exploration Project was signed January 1, 1979, between Utah, Getty and Lowell. The project was managed by Lowell who reported to a management committee which through most of the project consisted of Lowell, Francisco Ortiz, Robert Wheaton, Maurice Young, Sigfried Muessig and Louis Rove. Oliver Warin and Jim Bratt participated in the committee in the last phase of the contract. Special thanks are due Louis Rove of Getty and Maurice Young of Utah who made contributions throughout the course of the project. Francisco Ortiz was resident manager through most of the project.

Jan 1, 1990

By H Catchpole, L FontbotT, J PTrez, M Ageneau, A Bendez·

In the world-class mining district of Morococha, epithermal polymetallic replacement bodies and veins overprint porphyry mineralisation and skarns related to subvolcanic intrusions of Miocene age, thus indicating ore formation in two different environments, separated in time or forming a continuum. The district covers an area of about 70 km2 in the north-western part of the Domo de Yauli complex in theWestern Cordillera of central Peru and is part of the Miocene polymetallic belt, also hosting the deposits of Colquijirca (Bendez· et al, 2008b) and Cerro de Pasco (Baumgartner, FontbotT and Vennemann, 2008). Multiple late-Miocene porphyry stocks intruded Permian, Triassic-Jurassic and late-Cretaceous sedimentary carbonate and volcano-sedimentary formations, as well as large mid-Miocene barren intrusions. Extensive field work and detailedmapping of different styles of orebodies suggest that ore formation in the area was related to the late-Miocene magmatism. Good outcrop conditions and superimposing of different mineralisation styles make Morococha an ideal location for studying ore-forming processes in a complex porphyry-related magmatic-hydrothermal system in which porphyry-to-epithermal transition occurred. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By Propser M, Szekely J

Flow maldistribution in the iron blast furnace has been studied analytically by the use of the vectorial form of the Ergun equation and experimentally via packed columns and a cold model of a blast furnace. Experimental results are presented showing the effect on fluid flow patterns of the following types of nonuniformities in a packed bed: the increased voidage at the wall ("wall effect"), the decreased voidage at the interface between layers of materials with different sizes and shapes, and the differences in resistance to flow of bulk regions of a column with different sizes and shapes. The proposed theory is applied to the calculation of fluid flow patterns for these nonuniformities. Velocity profiles, as calculated from these flow patterns, were found to agree reasonably well with experimental measurements obtained via hot wire anemometry techniques for laboratory scale packed columns. Calculated fluid flow patterns are presented for blast furnace burdens which show how flow patterns are affected by (a) coke segregation and (b) the relative differences in resistance to flow between coke and oxide pellet layers. For the cold model study, calculated flow patterns are presented based on photographs of a given burden distribution. The velocity profiles calculated from these flow patterns were found to agree reasonably well with the velocity profiles measured from the cold Model.

Jan 1, 1975

The Porphyry Gold Mine (150km NE of Kalgoorlie) was reopened in November 1983 with production commencing in April 1984. Original reserves quoted for the open pit were 822000 tonnes at 5.2 g/t Au based on wide spaced diamond drill holes. Close spaced grade control drilling has revealed some loss of tonnage and a significantly lower grade. In the area of the pit mined to 30 June 1985 this grade control reserve estimate contained 67% of the gold in the original ore reserve with the grade being 19% lower. It is anticipated that the final grade control reserve estimate will contain around 80-85% of the gold contained in the original reserve. There has been close agreement between the Mill Head grade (4.19 g/t Au) and the grade control predicted grade (4.2 g/t Au) confirming that dilution is not a major problem. After initial poor agreement (attributed to "lock-up" in the circuit) the bullion calculated head grade steadied out at 93% of the grade control prediction. This difference is considered to represent the geostatistical bias in the drill hole/crushed rock sampling. Gold recovery has been in the range 93-95% (compared with bullion calculated grade). The net result is that the recovered grade of ore mined to 30 June 1985 is 70% of the original ore reserve grade.

Jan 1, 1986

A study is presented of the theoretically possible initiation systems for outbursts and the subsequent propagation mechanism.Previous occurrences of outbursts and their correlation to the theoretical system are described. An estimation of the energy release from two energy sources, gas strain energy and rock/coal strain energy, is presented and the relative importance of each source in the severity of outbursts. Summary: The description of mechanisms of outbursting follows the examination of these phenomena at Collinsville in Bowen No. 2 mine and at Leichhardt Colliery, Blackwater. Quantitative material contained in the paper refers to Leichhardt Colliery, Blackwater. Clearly from the work carried out to date gas release has a major part to play in the out- bursting at both of these collieries. In the case of the December 1 1978 outburst at Leichhardt Colliery energy release estimates place gas strain energy release contributing eight times the energy of that from rock/coal strain energy. Even the normal outbursts at Leichhardt Colliery appear to show this trend. Estimates of energy released are for comparative purposes between gas and rock strain energy and the values obtained may be regarded as approximate.

Jan 1, 1980

By Harris RW, Wood BR

At any given time, the tidal force subjects massive regions to a spatially uniform load. The deformation of any large structure due to these forces is proportional to the elastic properties of the structure. In this aspect, the tidal force applies a load in a manner similar to that of a large-scale testing machine. Any anomalies in the measured tidal response must reflect alterations in the average elastic response of the massive structure. In the present work, tidal tilt measurements obtained in the wall of a large dam are used to infer changes in the response of the dam to applied loads. In particular, it is found that the dam response has changed by approximately 13 percent, on average, for two monitoring periods separated by 5 years. It is possible that these changes were produced by the different volumes of water in the dam for the monitoring periods. The tidal measurement technique can also be applied to monitor changes In the average structural response of large underground and surface masses relevant to coal and metal mines.

Jan 1, 1992

By Hayward P. G

Complex ores, characterised by intimate intergrowths between minerals, have previously been treated by flotation with limited success. The most common problem has been that the liberation size is often finer than the lower size limit for selection flotation. A technique has been developed in which the problem is overcome by the use of a selective agglomeration procedure in which the values are coalesced with oil to a size suitable for flotation prior to introduction into the flotation machine. A complex lead ore was characterised by QEM*SEM mineralogy as having a mean galena liberation size of 15 ¦m. The best recovery of lead at 50 per cent Pb grade by standard flotation was 53 per cent. After application of the procedure, 86 per cent recovery was obtained after a single cleaner step. The oil functions as a bridging liquid in the presence of conventional collectors which render the mineral oleophillic.

Jan 1, 1991

With the recent wider introduction of friction hoists of the Koepe type. for winding from depths of more than 3000 feet it has been found that failure by fatigue is the most common form of rope deterioration. Large numbers of wire breaks occur near the centre of the rope cross-section and it is difficult to detect these with certainty using the preferred d.c. magnetic test. For best results with conventional search coils their dimen- sions should be related to the typical wire break field pattern surrounding the longitudionally magnetised rope. The field of a broken wire was experimentally determined, using a Polish type MD6 Defectograph wire rope testing magnet and a short prepared length of rope with a movable simulated broken wire. The external field distortion perpendicular to the rope was measured by means of a gaussmeter and Hall probe. The advantages of this method are that terrestial magnetism and inherent rope "noise" have no effect on the results.

Jan 1, 1971

By Mitchell D

In recent years the need to provide increased ventilation to improve environmental conditions rather than to dilute firedamp has led to increasing interest in the use of recirculation. Present UK mining law prohibits recirculation in ventilation, but it has been permitted selectively by exemption granted by Hm Inspectorate of Mines and Quarries. The conditions of use imposed by these exemptions to safeguard the safety and health of miners are examined in detail, dealing separately with primary and auxiliary recirculation systems.

Jan 1, 1988

By Ward C. W

Conventional polygonal and block modelling techniques inadequately represent the grade-thickness distribution of some narrow shear and stratabound gold deposits. The polygonal influence of high-grade drill intercepts can result in overestimates of resource tonnages at high-grade cut-offs. Although block modelling methods provide grade smoothing and a better representation of structural continuity, the technique can lack precise definition of ore width. An alternative method known as Spatial Object Modelling (SOM) has been developed on MineMap software to overcome some of these modelling issues. This method does not rely on a uniform cell size and allows grade smoothing between resource intercepts in three-dimensional space. The SOM technique creates grade-thickness bars on regular, user-defined spacings which allow easy visual comparison of raw intercept data to the interpolated model. Model cell values are readily transformed into isopachs, isopleths and resource perimeters for reporting and mine planning purposes.

Jan 1, 1997

The Kennedy Siltstone Open Cut provides graded rock for stope filling. Rotary drilling of 310 mm blastholes with a Gardner Denver GD120 is used, and the successful application of an equilateral triangular drilling pattern is described. Charging practices and the development of bulk slurry handling are outlined. Blast monitoring plays an important role in K.S.O.C. drilling and blasting operations. The proximity of nearby residential areas (1300 m) and the Mount Isa Airport (4500 m) necessitates special attention with regard to the minimisation of both air blast and ground vibration levels. The application and control of drilling and blasting parameters has had a direct bear- ing on success of the mining operations and also played an important role in reducing the disturbance to the community.

Jan 1, 1978