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By D Bradshaw

The recovery of molybdenum at Kennecott Utah Copper (KUC) has become increasingly important as its demand and price have risen dramatically in the last few years. Consequently, the flotation behaviour of the molybdenum bearing mineral, molybdenite, has received a significant amount of attention. The flotation performance of molybdenite generally lags that of the copper sulfide minerals and is much more variable. There are many factors including particle size, liberation, surface slimes and oxidation that contribute to this and also much speculation as to the relative contribution of each of these factors. This paper discusses the morphology of the molybdenite found at KUC, the mineral associations in the different lithogical ores types and the effect that each of these has on flotation performance. Quantitative mineralogical analysis and an assessment of particle shapes are used to explain that flotation behaviour does not necessarily follow expected trends and that some behaviour is counter-intuitive. This unique behaviour can be explained by the morphology and anisotropic nature of molybdenite.

Jan 1, 2008

The object of this paper is to show in some detail the mining challenges that have been presented and overcome during the successful development of the main exhaust ventilation drive that will service the Ballarat East mine during its 20+ year lifespan. Topics to be discussed in this paper include the ground support regimes employed, the ground conditions encountered during construction, how the heading was recovered after falls of ground and the effectiveness of geotechnical probe drilling at Ballarat.

Jan 1, 2006

Excessive use of computers in teaching, especially in self-learning programs, may destroy creativity and initiative. It is essential that engineers remain innovative to develop new technology. Safety legislation may have hindered the Development of mine managers. It may be necessary to develop two distinct streams of mining engineers. One should be biased towards human relations and safety, to 'be a certificated mine manager, and the other should be mathematically based as a high-technology mining engineer who would not necessarily qualify for a certificate of competency without a postgraduate course.

Jan 1, 1986

The metallogenic belts of the Central Andes (iron, porphyry copper, polymetallic and tin) are genetically related to an eastward migrating magmatic arc. The polymetallic belt of the Bolivian Altiplano formed during Miocene arc broadening and lies in a critical position for understanding the genesis of this zonation. It is penecontemporaneous with parts of the copper and tin belts, and shares many characteristics with them. The differences between the belts result from contrasting volcanic and feeder stock geometry, depth of erosion and country rocks, and are not due to variations in magma chemistry, age or Benioff Zone depth. Polymetallic mineralisation in the Altiplano is epithermal in style and mostly related to flow-dome volcanism. The intermontane basinal setting precludes deep erosion to expose the epizonal feeder stocks and predicted porphyry copper mineralisation. In contrast, erosion of the less abundant stratovolcanoes of the Altiplano-Puna and Pampean Massif may expose contemporaneous Miocene porphyry copper mineralisation in subvolcanic stocks. The tin belt is coincident with the Paleozoic fold belt of the Eastern Cordillera. The occurrence of minor tin in Altiplano epithermal deposits hosted by Paleozoic sediments, and the persistence of tin mineralisation in the tin belt over 350Ma, suggests that Paleozoic sediments are the source of the tin.

Jan 1, 1987

By P J. Ellen

The selection of the ore haulage system is a key decision made in the development of an underground mine. The haulage system is one of the components that define a mineÆs ability to respond to changes in mining inventory and market conditions. The complexity of this decision for Telfer Deeps was affected by the realisation during the feasibility process that the true scale of the potential underground mineralisation at Telfer was still to be quantified. This paper provides an overview of the process used in the Telfer Project Feasibility Study to select an ore haulage system for Telfer Deeps. The purpose is to highlight the value of impartially approaching tasks of this type with a robust process. The process should be able to respond to issues identified as the task progresses towards the objective of finding the best solution for an ore haulage system for the mine. For Telfer Deeps, this process resulted in the selection of a haulage system built around a shaft. The systems considered during the feasibility are discussed and the components of the haulage system constructed for Telfer Deeps are described.

Jan 1, 2005

By Jackson S

An investigation into different aspects of importance in the understanding of explosibility of hybrid mixtures of coal dust, air and gases potentially found within mine workings through a comprehensive laboratory program of explosibility tests was conducted. Plotting of test results revealed that conditions of potential explosibility could be described using two dimensional flammability limit surfaces- for coal dust/oxygen; methane/oxygen; and coal dust/methane mixtures. From these plots, the three dimensional flammability envelopes defining the explosibility of the coal dust/methane/oxygen mixtures can be defined and illustrated for a coal sample. The surfaces of the three dimensional envelope describe limits which separate inert mixtures of coal dust and methane at varying oxygen levels from those concentrations which are ignitable under defined conditions. It is considered appropriate to generalise that the geometric shapes of these limit regions are applicable to all type classifications of coal dust. There are practical applications of these results to the underground environment.The action of free radical initiators in the propagation of a methane gas explosion was examined for its applicability to the flammability of coal dust/gas/air mixtures. The oxides of nitrogen or NO x radicals have influence upon the lean limits of flammability of hybrid mixtures and this is illustrated by use of three dimensional coordinate geometry. Gases can be introduced to the underground environment through the exhaust gases of diesel equipment. It is concluded that radical species can substantially increase the flammability of gas and dust flames and as a consequence raise risk of mine atmosphere explosibility.

Jan 1, 1998

In 1969, Queensland Mines Limited obtained two large Prospecting Authorities in Arnhem Land, Northern Territory, Australia. The Nabarlek uranium deposit containing some 12 000 t of U308 was discovered on one of these in June 1970. Mining and stockpiling of this deposit were completed in 1979 and processing to yellowcake, which commenced in June 1980, is expected to occupy an 8-10 year period. The continuation of exploration, essential for the company to become a longer- term producer, was inhibited in 1972 by a Federal Government "freeze" on exploration in Aboriginal Reserves in the Northern Territory. Subsequently, the procedure for explorers to gain access to exploration areas in Aboriginal land was radically changed by the proclamation of the Aboriginal Land Rights (Northern Territory) Act 1976. As a result of this Act and the associated administrative policies adopted by Governments, Queensland Mines Limited has not yet regained access to the exploration areas it formally held in the early 1970's.

Jan 1, 1986

By Boger D. V

Two industrial case studies in which detailed investigation of the flow behaviour of mineral slurries is used to assess the feasibility of pipeline solid transport are described. The first example deals with the pumping of highly concentrated bauxite tailings to disposal, while the second exam- ple examines the possibility of transporting high-density Victorian brown coal slurries which previously has been thought as uneconomical. It is demonstrated that these typical solid handling problems can be solved by a good understanding of the rheology of suspensions.

Jan 1, 1989

Coal losses and dilution are among a coal mine operators everyday problems. These losses and unwelcome additions are generated primar- ily by the stripping operation and secondly by the coal mining opera- tion. Losses in yield due to preparation plant efficiency are a separate issue although they may be related to the coal mining operation. The losses and dilution can be traced to the following operations: (A) Overburden or Interburden Removal (1) Removal of coal edge by blasting operations. (2) Removal of top of seam by drilling/blasting. (3) Removal of top of seam by stripping equipment. (4) Removal of coal edges by stripping equipment. (5) Dilution due to stripping equipment. (B) Coal Mining (for the case where seams are ripped rather than shot) (1) Coal rib losses. (2) Coal rib dilution. (3) Coal left in floor. (4) Coal left in fault areas. (5) Floor material picked up whilst loading. (6) Spoil material picked up. (7) Spoil material from poor surface clean up. (8) Top of coal losses from final clean up. (9) Dilution from ripping too deep, i.e. into floor below seam. (10) Dilution from interseam parting. The losses apply to both the single seam and multi seam oper- ations although they are more pronounced in the multi seam mines than in a single seam mine due to the position of the coal which is lost. For example in the multi seam case the top seam coal edge loss is final. There is little chance of recovery with the subsequent pass even if the extra rehandle is done. However conversely the lower seam is relatively easy to locate as it has nowhere to go being contained by the lowwall bench.

Jan 1, 1988

The implementation, during recent years, of the concept of distributing chilled water to improve cooling at the working faces represents a very important innovation for the mining world. In a logical extension to that concept it has been recognized that distribution of the cooling water at high pressure would provide a potential source of energy for driving water powered hydraulic machinery such as rockdrills, water jets for moving rock, and support props, in the workings. With this in mind, the Research Organization of the Chamber of Mines of South Africa is pursuing the development of such a dual system that will provide cooling in a deep mine and, at the same time, drive hydraulic machinery. A comprehensive design of such a system has been completed and has shown the concept to be entirely feasible technically using technologies currently available. A pilot system is working in a mine shaft 2000 m deep giving a pressure of 20 MPa at the bottom of the shaft and distributing the cold water into the workings at a pressure of 17 MPa. The system shows considerable potential for improving existing mining methods and will open the way for the development of new mining methods for deep mining operations.

Jan 1, 1986

The paper contains the publication of timber shapes recovered from the Burra Mines during open cut operations in the 1970s. The timber was in the process of being disposed of for fire wood. All timber shapes still in existence in September 1990 were drawn.The collection revealed a number of different types of caps and legs. There were also end plates and wall plates from what appeared to be a hanging sets of shaft timber.

Jan 1, 1993

By Hirose K, Itakura K

A new global stiffness matrix evaluates the performance of powered supports by estimating and comparing the global stiffness matrices of ten different types of powered supports with lemniscate linkages, each support having its own deformation characteristics. Expanding the global stiffness matrix allows the implementation of a finite element scheme to analyse the interaction between the powered support and the strata around the coal face.The evaluation of performance by the stiffness matrix method shows that 4-leg chock shields possess both the desirable convergence and shear deformation stiffness properties. The finite element analysis also confirms that 4-leg chock shields present well balanced performance for controlling strata around the coal face.

Jan 1, 1991

The Tick Hill Gold Mine is situated approximately 110 kilometres south of Mount Isa, and 14 kilometres north of the township of The Monument. It was discovered in October 1989 by Mount Isa Mines Exploration in an area which had been targeted as high in potential for copper-gold mineralization.A mining lease application was made in March 1990. Mining, and the construction of the plant and infrastructure, began'in early August 1991 after the lease was granted on 20 June of that year. Commissioning of the plant began in December 1991, and the first gold was poured on site on 31 December 1991.The development of the underground mining operation commenced in January 1992 with the drilling of the ventilation shaft. The access decline was started in March of the same year, with the first ore produced from underground in August.

Jan 1, 1993

By White A, Price G

The main assets of a mining company are its orebodies; the second are the people who find and use them.The graphs in Figure 1 were derived from a paper by Rob Macdonald of Rothschild Australia presented to The AusIMM Centenary Conference in Adelaide earlier this year. They show that the value of the industry on the Australian Stock Exchange halved over the past decade, despite the re-investment of capital equivalent to its full market capitalisation. Why is this so? The average dividend yields for the ASX Mining Index was never above five per cent during that period and barely averaged 2.5 per cent. Why then is $Ai million capital re-investment per employee since 1960 not enough to generate a rate of return to investors better than lousy bank interest? Do the investing public no longer regard our industry's assets to be world class?

Jan 1, 1993

By C Ward, U Mueller

Compositional geostatistics is an approach developed to ensure that the constant sum constraint induced by geochemical iron ore analysis is respected in estimation and simulation. Jack-knifing and cross-validation were used within this framework to compare the results from ordinary cokriging of the additive log ratio (alr) variables with those from conventional ordinary cokriging. Two methods were used to back-transform the alr estimates: the crude additive generalised logistic back transformation and numerical integration via Gauss-Hermite quadrature. Previous work on a blasthole data set from a Yilgarn iron ore mine showed promising results, with the Gauss-Hermite quadrature method returning results comparable to ordinary cokriging from the point of view of bias, but superior in that the constant sum constraint imposed by geochemistry of the data was honoured. Other practitioners have noted that the linear interpolation of non-linear log ratio transformations will result in biased results, and that this bias can be masked in a (grade control) setting where the spatial density is high. To test this assertion, the methodology has been extended to successively lower spatial density data sets. The results and applicability to routine iron estimation are discussed.CITATION:Ward, C and Mueller, U, 2013. Compositions, log ratios and bias - from grade control to resource definition, in Proceedings Iron Ore 2013 , pp 313-320 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

The physical phenomena which influence gas flow in the bosh and hearth of a blast furnace are discussed including the hold-up of slag as a mechanism which can result in a flooding condition. An equation is defined which describes the limitation to wind volume arising from the flooding condition. Implications of the various factors influencing bosh and hearth gas flow on furnace operation are discussed. Coke quality is shown to be the most important factor in the aerodynamics of these zones and coke requirements are defined for the Port Kembla No. 5 BF which has an inner volume of 2670 m3.

Jan 1, 1975

By Murphy MW, Klaric SD

The history, operation and design of the Secor continuous rod production process is described. The effective operation of the plant is influenced by accurate monitoring and control of molten metal properties, mould release application, coolant application and composition and correct setting of all operating parameters. The continuity of operations, which is an essential feature of this type of plant, is also greatly influenced by the service life of wear parts in the operation. This paper deals with three principal wear parts which come into direct contact with copper during operation, these are:

Jan 1, 1985

By Kyle J. H, Misra V. N

The recovery of copper from a flotation concentrate using ferric chloride leaching has been investigated. The concentrate from the Horseshoe Lights Mine near Meekatharra, Western Australia, contained mainly digenite, pyrite and talc minerals. Over 95 per cent of the copper was dissolved in an acidified ferric chloride solution in one hour at 70¦C and ambient pressure. The pyrite and gangue minerals did not react. The leaching process was found to consist of four separate reactions and the shrinking core model was used to describe the process. The effects of particle size, temperature, concentration of FeCls, stirring speed and leaching time on metal dissolution were investigated. The apparent activation energies in the second, third and fourth reactions of leaching of copper concentrate were 28.8, 11.9 and 53.9 kJ/mol, respectively. The optimum conditions for the leaching of copper from the concentrate, within the range of conditions studied were: particle size 63 per cent minus 38 ¦m, a ferric chloride concentration of 1.48 M, a temperature of 70¦C, and a stirring speed of 800 rpm.

Jan 1, 1991

By Coulborn W. T, Glasby G. P, Maylan M. A

Research cruises by HMNZS 'Tui' (1986) and RV 'Moana Wave' (1987) investigated the geology, geophysics and seafloor mineral resources of Manihiki Plateau in the central Pacific Ocean.Manihiki Plateau is a large (500,000 km2) mid-ocean platform that rises 3000 m above the abyssal plains of surrounding ocean basins (depth -5500 m). Its foundation evolved about 112 Ma ago by massive outpouring of basaltic lavas at a plate triple junction. The plateau is blanketed by a 900 m thick sedimentary section comprising (i) mid-Late Cretaceous volcaniclastic sandstones / siltstones grading upwards to limestones / chalks and (ii) -500 m of Tertiary nanno-foram chalks and oozes. Cores from DSDP 317 drill-site on the Manihiki High Plateau indicate that the volcaniclastic sediments contain native copper and some thin beds rich in organic carbon.

Jan 1, 1990

By Muchi I

To clarify the characteristics of non-uniform flow of gas through layered burdens of ore and coke, flow equations of continuity and motion were solved numerically taking account of the geometrical effect of a bed. The results are compared with that predicted by an approximate solution. A mathematical-kinetic model for determining the distributions of process variables over the region from the top to the melting level of blast furnace with the horizontal or the inclined layers of burdens is developed in consideration of the uneven gas flow. By the use of this model, the longitudinal and the radial distributions of process variables in an existing blast furnace in Japan were calculated with the aid of a digital computer. Computed results show that the process variables and the melting level change remarkably over the cross-section of the furnace and that the patterns of these distributions are similar to the results observed by other investigators.

Jan 1, 1975