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The mineralogy, maero- and micro-textures of Thackaringa ore are simple and have many counterparts among base metal-quartz-siderite vein type deposits elsewhere.The ore consists predominantly of galena, sphalerlte, chalcopyrite, tetrahedrite, and arsenopyrite in a quartz and siderite gangue. Silver minerals, as such, appear to be lacking and silver values are no higher than in other sulphide ores of this type. These features contrast very markedly with those of the A.B.H. Consols Lode which appears to have emanated from the north end of the Broken Hill Main Lode Horizon during high grade regional metamorphism. The Consols Lode has been regarded as of Thackaringa type, and both are regarded as possibly arising from the remobilization of Main Lode Horizon ore. Whilst this may yet prove to be so it appears that the marked differences in mineral composition between the Consols and the Thackaringa types, would require somewhat different modes of regeneration.Thackaringa ore, as well as A.B.H. Consols ore, on this basis, would necessitate the development of a metahydrothermal ore fluid to account for their present apparently hydrothermal (or pseudo-hydrothermal) constitution...

Jan 1, 1967

By Ulvelin K, Antila K

Large scale cut and fill mining in narrow silver-lead-zinc orebodies began at Mount Isa in 1964. Initially each orebody was one stope and access was via raises from the level above. Upholing was the principal mining method, although flatbacking was employed where ground conditions were more difficult. Developments since have included access via footwall inclines and connection of all stopes with major crosscuts. Flatbacking is the principal method. The most recent cut and fill operation is now fully mechanised using drilling jumbos, rockbolting jumbos and load-haul-dump units. Improved ground support and drilling and blasting practices have enhanced safety, recovery and productivity in all cut and fill operations.

Jan 1, 1988

By Bennet A. G

As part of the construction of the Melbourne Underground Rail Loop it was necessary to construct two 7 metre diameter tunnels, each 100 metres in length, by shield driven excavation through an alluvial valley at Elizabeth Street. The tunnels had a primary support of bolted precast reinforced concrete liner blocks and were excavated with the aid of compressed air. The work was undertaken by the Tunnelling Group of the Melbourne and Metropolitan Board of Works as nominated sub-contractor to John Holland (Constructions) Pty. Ltd. The paper describes some of the problems associated with the construction of the above tunnels and the methods used to overcome them. In particular

Jan 1, 1981

By A J. Tucker, L Bottomley

The principle objective of development mining is to create thoroughfares that can be accessed by personnel and machinery for the entire life of an underground mine. The drill and blast process, being the primary method used when creating these thoroughfares, needs to be able to adequately fracture the rock to be removed whilst at the same time minimising any damage that may be sustained to the rock surface that remains. This process of damage prevention is known by a variety of different names including smooth blasting, sculpture blasting, contour blasting and controlled blasting. Whilst the terms are different, the objective is the same and that is to reduce and better distribute the explosive charges to minimise stressing and fracturing of the rock beyond the neat excavation line. The process in this report will be referred to as perimeter control blasting. This paper will discuss the benefits of using perimeter control blasting in a development mining operation and the theories that govern how these blasting techniques work. The methods that are used to implement perimeter control blasting will also be addressed, paying particular attention to how these blasting techniques have evolved, spawning new and improved perimeter control products. Finally some attention will be given to the process of optimising perimeter control blasting in any underground mining operation.

Jan 1, 2005

By Hayes P. C, Matthew S. P

The product morphologies formed on the reduction of dense wustite crystals are classified into three types, A) porous iron, B) porous wustite covered with dense iron, and C) dense wustite covered with dense iron. The mechanisms of formation of these structures and the effects of impurity elements on the product morphologies are discussed.

Jan 1, 1985

By Hengst B

The first production stage in any mining operation is the breaking of whole rock into fragments small enough for loading and subseq- uent handling. This primary fragmentation is most frequently accomplished with blasting. The maximum fragment size and the fragment size distribution have an influence on the subsequent loading, handling and crushing costs. It is assumed that total rock fragmen- tation in practice is a result of an interact- ing array of radial cracks from various blastholes. The representation for the basic pattern of radial cracks emitted from a particular blasthole is first described. A model is then developed simulating the interaction between blastholes at various burdens and spacings, and in simultaneous and delayed modes. The resultant picture is analysed and a fragment size distribution calculated. Methods of incorporating the existing faults in the rock are also discussed. Finally application of this model to various facets of mining are considered.

Jan 1, 1977

Basic premises for evaluating special characteristics of gold-bearing porphyry metal systems stem from their contrasts with properties of the class as a whole. Included features are differences in geologic, thus tectonic, environments, subtle but real differences in the proportions of accessory metals Mo-Ag-Au that are regionally and within some regions, tempo-rally distinct, contrasts in the Ag:Au ratios, petrological-geo-chemical as well as isotopic differences between intrusive suites, the age and nature of host terranes, contrasts in alter-ation style, and zoning variations of mineralogical and physical properties of rocks. These properties are linked in various ways in different regions and suggest that in large gold-bearing systems where gold may be uniformly distributed, environ-ments of emplacement, and compositions or sources of igneous "progenitors" may dominate in importance over processes, and that systems in which gold is zoned are processes-dominant.

Jan 1, 1990

By Williams SR

Column Flotation cannot be used indiscriminately. Based on extensive pilot plant experience at Lakefield Research, a number of limiting parameters have been identified for the application of column cell flotation. Parameters of importance are the use of wash water, flotable mineral content, pulp viscosity, type of mineral selectivity being sodght and degree of mineral liberation. The paper discusses when wash water should be used and the positioning of a column within the circuit as this is important to maintain a sound water balance for the circuit and prevent excessive circulating loads. Other areas of debate are pulp chemistry, very low and high weight recovery, for which the conventional column is a poor selection of equipment, and treatment of complex ores, where the separation of valuable minerals is more difficult than non-sulphide, sulphide mineral separation. Based on these observations, the application of column flotation must be carefully considered or can be optimised.

Jan 1, 1993

By C Gypton

This paper gives some insights into what to look for when reviewing feasibility studies. The review by a third party is an important element of the risk management process and may be the last remaining opportunity to uncover errors, or identify and reduce project risks on paper before they are converted to financial disappointments, steel and concrete monuments to process failures or cost overruns. The mining industry has had a spotty record in the area of estimating initial capital costs and operational performance, even though the standard of feasibility studies is generally acknowledged to have improved in the last decades. Third party reviews rarely have the luxury of enough time and unlimited funds, so where should the reviewers focus their efforts to be most effective? Assuming that the project already apparently meets investment criteria, the authors suggest where and how to look among fundamental project parameters for signs that serious flaws exist that have the potential to become project killers. We also give advice on how to review cost estimates without becoming lost in the details. The paper is supported with numerous actual examples.

Jan 1, 2003

By Vidalinc, Raffoux

Longwall faces producing in the order of 20,000 tons per day of raw coal are presently running in the Houilleres du Bassin de Lorraine of Charbonnages de France. Production levels of twice that level pose some technical and economic problems of coal cutting, ventilation, coal and equipment transportation in the.face and from the face to the sur- face. The peak productions of the equipment in use today, the results of trials with new equipment, the utili- sation of forecasting models (some in the form of software), allow us to fo- resee feasable technical solutions to these problems. They will first be considered in the best possible context (thick- ness, dip, non gassy, soft coal, good strata, no faults). This will give. the necessary conditions to reach daily output'of that level. A sensitivity analysis of these- figures to the effective natural con- ditions will then be undertaken and the implication of such a project on health and safety (dust, climate ...) will be carefully considered. A concise technical and econo- mical approach will permit us to fore- cast the economical interferences of such production units and specially the consequences of sudden variations of the output (downtimes, failures, etc). From this investigation, goals for technological development and re- search areas will be outlined to be able to reach this production target in the XXIst century.

Jan 1, 1988

In line with mining operations throughout Australia, Western Mining Corporation Limiter' is striving to increase productivity by intro-ducing mechanized mining techniques wherever possible. Kambalda Nickel Operations' (K.N.O.) largest operating nickel mine, Long Shaft, is currently introducing mechanized cut and fill methods which must provide flexibility to cater for an orebody that variesconsiderably in width, both along the strike and up dip.This has resulted in modifications to the previous approach to primary level develop-ment, and intermediate stope development, and in the type of development and production equipment being employed. Electric-hydraulic diesel jumbos and diesel loaders have now been mated with conventional rail equipment and production airtrack machines are being utilized.The transition to mechanized methods is in its preliminary phase and is being monitored closely to ensure any productivity gains are not offset by a substantial drop in mine grade. The precise method ofmechanized mining has not been finalized and selective methods will be used, according to the ore width and ground conditions, which vary throughout the mine.

Jan 1, 1985

By Bingwen Z, Fengyi K

The hydraulic-stowing mining method is most effective for mining thick coal seams. It is superior to the sliced cover- caving and artificial mining method and the fully mechanized sublevel-caving mining method for the following reasons - a much higher recovery rate is achieved, there is much less surface subsidence and roof pressure, there is no hidden danger of gob fire, and much less methane emission and coal dust problems, etc.. However, its superiority is overshadowed by its backward stowing technique which makes mechanisation of mining and stowing difficult, causes bleed water interference to production and to the environment and is uneconomic because of the high cost of stowing material. These disadvantages limited its application to coal seams that are difficult and not suitable to be mined by other mining methods. The remedy is in reforming it thoroughly to permit mining of otherwise unminable seams and this paper presents the reformation.

Jan 1, 1992

The preferred alternatives in heap design and their motivation are identified as- -normal heap leaching, to be generally applied wherever possible, - flooded vat leaching, to be appliedwhere wetted ore lacks adequate cohesion or if limited space necessitates it,- thin layer leaching, to be applied where deleterious vat chemistry necessitates it.A number of the following features would probably be incorporated in the optimization of normal local heap leach operations- pre-cyanidation - pre-agglomeration - retaining walls- staged (counter-current) heap treatment- control of calcium levels- reduced pH and trickler irrigation

Jan 1, 1984

The original leases making up today's North Kalgurli Mines were developed by independent companies on an ad hoc basis. The major disadvantage which now arises is the varying levels of mining horizons. From Kalgurli Shaft in the south, through main Shaft and to Croesus Shaft in the north, there are three separate sets of levels. work has commenced to link the three areas with either common levels or new development which will facilitate common access and haulage via Main Shaft.Generally, the workings at North Kalgurli were established at the turn of the century. The introduction of techniques and equipment to bring the mine into the 20th Century has been difficult and slow. The general size of openings, a widespread workforce and complex ore distribution often make innovation and change more than a challenge.

Jan 1, 1985

By Johnson RD

The variation in coal properties and the coal seam reduced level can be analysed using partial trend-surface analysis techniques. For the area studied seam reduced level and seam thickness data from the Bulli Coal yield trend-surfaces with a high coefficient of determination, since they have relatively small systematic local and random components in their overall variation. Sulphur content appears to have no significant re.gi_onal trend, and phosphorus content has a very weak regional trend. Other analytical variables have regional trends which are of intermediate strength. The strike-directions of.the statistically significant first degree! trend-surface are similar, sug-gesting.: that the variation of the several coal properties was controlled by a set of- related causes. The relations apparent from the dip and strike of the first degree trend-surfaces are similar to- those which are apparent from the trend- surface residuals and'from the results' of canonical trend-surface analysis.'.. It is probable that differential subsidence controlled the areal

Jan 1, 1975

By A S. M A Haseeb

Zircon is the second in abundance among the heavy minerals occurring in the beach sand along the coastal belt of Bangladesh. In this study a detailed characterisation of Bangladesh zircon extracted at the pilot plant of the Bangladesh Atomic Energy Commission at CoxÆs Bazar has been attempted using chemical analysis, X-ray diffraction and optical microscopy. From the chemical analysis it is found that Bangladesh zircon has a purity of 95.88 per cent. The main impurity in Bangladesh zircon is titanium oxide (3.01 per cent). This is followed by iron oxide (0.42 per cent). A number of other oxides are also found. Microscopic study revealed that Bangladesh zircon has an elongated, prismatic shape with pyramidal termination in about half of the grains while the rest are more or less rounded. Some fractured and irregular grains are also found. Bulk sample of Bangladesh zircon in the as-received condition shows a yellowish brown color. However, individual zircon grains are seen to be almost colourless and transparent under polarised light. XRD study confirmed good crystallinity in the sample. Under the microscope it is found that zircon grains constitute 94 per cent while total impurities amount to six per cent in Bangladesh zircon. This result agrees fairly well with the chemical analysis results. Microscopic study identifies oxides of titanium (both rutile and ilmenite) to be the main impurity, in conformity with the findings of chemical analysis. Further, monazite was also identified as an impurity under the microscope. An iron bearing coating is also found on a few zircon grains. Most of the impurities found in Bangladesh zircon exist as discrete minerals.

Jan 1, 2000

By M P. Sandy

Some Western Australian underground mines are challenged by very high stress gradients. This environment frequently results in poor induced ground conditions and damaging seismic activity. In some cases, rockbursting or squeezing ground has been observed as shallow as 250 m below surface. Very few mines operating at depths greater than 500 m experience no stress-related issues. As a general result of this difficult environment, there are a growing number of mines that are now challenged or have been closed by induced geotechnical problems. Often, the up-front savings or perceived advantage of an inappropriate mine plan may be entirely lost to the real cost of managing the hazards, or a write-down of reserves resulting from access difficulties will diminish the economic position of the mine. From an engineering perspective, it is best if stress-related hazards can be proactively minimised, because reactive measures offer less improvement in risk exposure. In this paper, some examples of sequencing techniques for managing difficult environments are contrasted with examples from mines where developing hazards have adversely affected production or the economic viability of the project.

Jan 1, 2003

By Elliot B. J

Cobalt is principally produced by hydrometallurgical means from the copper-cobalt ores of Zambia and Zaire. In addition cobalt is commonly found in minor quantities in association with nickel and copper-nickel orebodies. Generally the level of cobalt common to these latter orebodies does not warrant separate processing unless the metal price reaches levels last achieved in 1979 and 1980. For pyrometallurgical processing the distribution of cobalt and the factors which affect the distribution of cobalt between matte and slag are not well understood. A limited amount of fundamental research has been completed on cobalt distribution both for simple oxide and matte systems. The paper briefly reviews the relevant literature on theoretical aspects of cobalt distribution between metal and slag and the deportment of cobalt in sulphide smelting circuits. The deportment of cobalt in the Kalgoorlie Nickel Smelter circuit is critically analysed and areas where recovery improvements may be achieved are highlighted.

Jan 1, 1989

By Floyd JM

Pilot plant trials showed the effective ness of the submerged lance SIROSMELT technology for altering the composition of iron blast furnace slags as a preliminary step to produc- tion of formed materials. Mixtures of oil and air were injected into a bath of liquid slag to provide the heat required for melting the additives and to provide very turbulent conditions which resulted in complete dissol- ution of added fluorspar within one minute and almost complete dissolution of silica in two minutes. Sulphur lost during injection was readily made up by addition of pyrite or pyrrhotite. A stable foam could be readily made and broken down and the foamed slag appeared suitable for extrusion or forming into shapes.

Jan 1, 1979

By Aylmore M. G

Samples have been taken from a two-stage industrial gold roaster treating a pyrite/pyrrhotite/arsenopyrite concentrate, in order to describe the mineralogy, composition and surface area of the calcines. Sulphides oxidised to produce a porous magnetite in the first stage and a porous hematite in the second; pyrite predominantly roasted via a pyrrhotite intermediate. Sulphur was eliminated in both the first and second stages whereas arsenic was eliminated in the first but retained in the second, partly as rims on hematite particles. The finer sized particles from the cyclones and electrostatic precipitator, while having the greatest surface area, were the most refractory with respect to gold solubilisation, probably as a result of incomplete decomposition (through short-circuiting) in the first stage, and through a combination of factors such as overheating and entrapment of sub-microscopic gold in the second stage.

Jan 1, 1992