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By Tiu C, Sarmiento G, Uhlherr PHT

Fundamental rheological properties of slowly settling mineral slurries are reviewed. Slurry flow is discussed in terms of observed shear stress-shear rate behaviour. Particular emphasis is placed on establishing procedures for scale-up and design. Flow property measure- ments on red mud, a waste product from the Bayer alumina process, are presented and used to illustrate recommended design procedures.

Jan 1, 1978

By D Monaghan

Pumping water for dewatering and water supply is a major component of electricity consumption at mining operations and hence is a significant contributor of greenhouse gas emissions. Pump systems at a typical mine site can be broadly split between above ground centrifugal pumps (generally used for water transfer) and submersible borehole pumps (generally for dewatering and/or water supply). In contrast to above ground pumps, submersible borehole pumps can be subjected to varying duty points (total pumping head and flow requirements) as a result of changing bore water levels and yields, particularly in mine dewatering bores. Typically, much higher pumping rates are required at the commencement of dewatering to remove groundwater storage and to intercept sufficient groundwater throughflow to achieve target drawdowns. Once target drawdown levels are reached it often only requires much lower pumping rates to maintain target drawdowns. Pumps sized to remove the large initial volumes of stored groundwater often end up too large for the lower flow rate required for æmaintenance pumpingÆ. This often results in pumps operating inefficiently, a problem which can be made worse when pumps are throttled to reduce the pump output to better match the reduced bore yield. Current standard operating practice places little emphasis on the electricity consumed by pumps, with the focus often being on minimising capital expenditure (æIf it ainÆt broke donÆt fix itÆ). Submersible pumps can have extended service lives of ten to 20+ years. However as the capital cost of a pump typically represents only five per cent of the life cycle cost, the vast majority of the life cycle cost is energy usage.Through the implementation of a regular review of the operation of borehole pumps, significant reductions in electricity use and associated greenhouse gas emissions can be achieved without impacting the dewatering schedule. In most cases, the capital cost of replacing pumps is more than offset by savings in operating costs. These potential savings become even more significant when considering proposed future carbon tax levees.This paper presents examples of the opportunities for significant reductions in energy, greenhouse gas emissions and overall costs that can be achieved for a range of dewatering scenarios.

Jan 1, 2009

Applications of chlorine metallurgy to the extraction of metals often result in the production of volatile metallic chlorides, most of which condense directly to a solid phase at one atmosphere pressure. A stirred bed condenser suitable for th

Jan 1, 1980

A test model is presented for the simulation of dewatering by gas injection of a porous aquifer above longwall workings. A finite difference model used in the oil industry was modified to match the underground mining conditions. The model is suitable to cope with the problem of dewatering reservoirs of low transmissivity. After comparing more versions, it has been concluded, that the investigated dewatering method can be proposed under special hydrogeological conditions only.

Jan 1, 1988

By Slattery T. E

Recent develognents in zinc flotation at the North Broken Hill Limited concentrator are discussed. An outline of the history of zinc flotation and a description of current practice is presented. Installation of on-stream X-ray analysis probes has resulted in inproved metallurgical performance and focussed attention on automatic control. Results are presented of investigations made over the past six years which have led to the formulation of experimental schemes for the automatic control of zinc flotation.

Jan 1, 1983

By LeJuge G. E, McKenzie C. K

Innovative mining and blasting techniques were demanded at the Richmont Mines, Francoeur Mine in Quebec, Canada, by a narrow, shallowly dipping high grade gold ore body. The ore body being mined occurs as a thin tabular deposit varying in thickness between 1.5 and 3.7 metres, and dipping at 36¦. The mine proposed experimenting with open stoping techniques using small diameter drill-holes. The hangingwall required progressive, full face rockbolting after each production blast, utilising a specially manufactured machine which provided access to the hangingwall for both scaling and bolting. Blasted material is mucked from the stope by scraper and hoisted directly to surface without benefit of primary crushing.

Jan 1, 1992

Proposals designed to use stockpiles and buffer stocks to achieve price stabilization and better resource use have a long history. They are super- ficially simple to understand. The benefits seem clear. And yet I am well aware that this is not a simple subject: the more one studies it, the more complex it becomes. Worldwide interest in re- source management, while receiving fresh impetus from the OPEC actions, also has a long and chequered history. Those venturing into such ter- ritories must be forewarned of the traps and pit- falls which abound. Interest in these schemes has waxed and waned over the years with the fluctuating fortunes of the producers or consumers. As I write this paper towards the end of 1977, I am acutely aware of the low ruling prices for zinc, copper, and nickel. These sacrifice prices remind me that it is difficult, for example, for a surveyor, to be calm and rational if he is up to his neck in a swamp full of crocodiles. He might be forgiven for forgetting that the aim was to drain the swamp! I am also aware that when swamps are drained, painful and dangerous stumps sometimes stick out. Hence, in looking at the subject of stockpiles and resource management we must not set our sights too high, perhaps not initially hope for perfec- tion, if we want to secure worthwhile changes. My approach is to acknowledge a bias for the market system. We have, however, had experience (remember the 1930s) of some weaknesses in the untrammelled operation of free markets. Thus our international economic relationships over the past 20 or 30 years have been based on a desire to retain as much as possible of a liberal world trading system backed by such organizations as the GATT, IMF, and the U.N. to ensure the necessary cooperation. Some nations have seen this system work only partially in their best in- terests. GATT, for example, has been reasonably effective in liberalizing trade in many manufac- tured goods but far less so in regard to agricultural or semi-processed goods.

Jan 1, 1978

Consideration is given to the factors affecting raceway activity and the hearth design of a zinc-lead blast furnace. Results of measurements made on operating furnaces are given and comparisons are made with published data both from operating iron blast furnaces and from dynamic models of the zinc-lead blast furnace. Indication is given of the methods used for assembly of the relevant information into the specification of a commercial furnace design. A discussion on the comparative merits of furnaces of circular and essentially rectangular plan is given based on the concepts explained in the paper.

Jan 1, 1981

By Eggleton T, Taylor G

The lateral and vertical distributions of gold and a wide range of other elements in the regolith, close to Au and Cu mineralisation have been investigated at Goonumbla, NSW. Open cut mining has exposed deeply weathered profiles which have been used for this investigation. Determination of secondary mineralogy and micromorphology of profiles have facilitated the broad interpretation of processes that determine element mobility and dispersion from primary mineralisation as a result of weathering. This in turn has led to better interpretation of geochemical data and enhanced understanding and knowledge of regolith geochemical processes which are invaluable in the formulation of improved exploration Procedures.

Jan 1, 1997

By D Kent, J Kirkpatrick

The mining industry has long wanted a single communication back bone to cover the majority of their requirements underground. The convergence of communication technologies in the office/surface environment has been identified by the mining industry as a means to achieve their long-standing goal. In particular use of Internet Protocol (IP) systems are seen as proving a basis for a mineÆs communication infrastructure. This paper presents the development philosophy and work undertaken by Inco Limited in Canada, as well as the implications of this on suppliers to enable the technology to be mine worthy and readily available.

Jan 1, 2005

The introduction of on-stream analysis in flotation circuits has raised the possibility of automatic control of flotation performance by digital computers. The development of control strategies for an industrial zinc cir- cuit is discussed with reference to identifi- cation of the major disturbances, investigation into the performance of the circuit, the design of the control algorithms, the testing of their performance and their implementation in a production environment.

Jan 1, 1983

By G L. Simmons, K M. LeVier, R Kappes

The low potential hydrophobic state of pyrite in amyl xanthate (PAX) flotation with nitrogen is of particular interest with regard to the N2TEC flotation technology currently being used for the recovery of auriferous pyrite at NewmontÆs Lone Tree Plant in Nevada. Initially, the N2TEC system had been found to operate satisfactorily, but cyanide in the flotation mill water appeared to be responsible for a loss in pyrite recovery. This supposition was confirmed with laboratory experiments, and a program was initiated to study flotation chemistry variables by electrochemically controlled contact angle measurements. Experimental results show that activation of pyrite in such cyanide solutions can be achieved more effectively with lead than with copper. Subsequently, based on these fundamental studies, significant improvement at the Lone Tree Plant was achieved by lead activation, in which case the recovery increased to expected levels. The effect of activator is particularly significant not only with respect to pyrite depression by residual cyanide, but also with respect to collector (PAX) consumption and the initial state of the pyrite surface. Experimental results show the importance of the pyrite surface state and the rather interesting features of the activation process.

Jan 1, 2005

By Lane D. P, Malone J. G

The slag fuming furnaces are the major bottleneck in the BHAS zinc production flowsheet. Intensification of the fuming process could significantly reduce this production restriction. Oxygen enrichment was proven to be a means of intensifying the fuming process. This procedure resulted in higher slag bath temperatures, and development work was undertaken towards obtaining accurate slag bath temperature measurement and control. Slag bath temperature measurement techniques were evaluated, with infra red optical pyrometry established as the system with the most potential for continuous temperature measurement and control. Oxygen enrichment resulted in a zinc production capacity increase of 1 000 tonnes per year. An oxygen enrichment technique was developed which both minimized the risk of furnace damage and made the most efficient use of the enrichment oxygen.

Jan 1, 1989

By Hall C. E, Chrisholm J. M

Resource calculations for shear hosted deposits of any type are difficult regardless of which calculation technique is used. One of the main problems is the determination of the geometry of the mineralisation. Once this has been elucidated then the appropriate resource calculation methodology can be employed with a search distance and orientation that is relevant.

Jan 1, 1993

By McNicol J. H

Using a small scale laboratory pilot plant a series of tests have been conducted with the aim of investigating the influence of the zinc/acid ratio on the efficiency of zinc electrodeposition from an acidic sulphate solution. The results have shown that current efficiency is increased as the zinc/acid ratio is increased with no evidence of an optimum zinc/acid ratio. However the choice of a zinc/acid ratio for full scale operations must be a compromise between other parameters, spent electrolyte acidity and power efficiency, which also impact upon plant performance. The effect of various impurities has also been monitored and antimony, nickel and tin have been shown to be deliterious to current efficiency.

Jan 1, 1989

The impulsive loading tests under confining pressure were performed to investigate the dynamic fracture properties of rocks in a triaxial stress state. The apparatus in this study consists of the Split Hopkinson pressure bar, a pressure vessel and hydraulic actuator. Magnetite-quartzite and limestone were selected for the test. The stress-strain curves and fracture strength under confining pressure obtaind in the tests were compared with those of the conventional triaxial tests. Finally it is concluded that on the effect of dynamic that on the effect of dynamic compressive strength of rock, dynamic elastic coefficient of rock and confining pressure etc. on the blasting result

Jan 1, 1990

By Lindner E, Bosio M

South Australian coals are all low in rank and generally poor in quality, with difficult combustion characteristics. This circumstance makes the selection of a fuel source for future power generation difficult, requiring careful study and detailed analysis of the various alternatives. Combustion characteristics can have a significant effect on plant design and costs, and need early attention in any exploration and evaluation programme. The physical location of the deposits, often remote from established infrastructure and centres of population, is also a major factor in the ultimate cost of power at the poirl use.

Jan 1, 1977

A survey of derelict and active alluvial tin and sapphire mines in the Emmaville area of northern N.S.W. as the first step in a pro- gramme of similar surveys to be undertaken throughout the State by the State Pollution Control Commission is presented. Thirty nine individual mine sites in the study area were included in the survey and an assessment made of the current level of impact on the environment at each site by assigning values of "magnitude" and "importance" to a number of impacting factors. Results are pre- sented in matrix form and mine sites ranked in order of impact "importance". Examples of alluvial tin, underground tin/arsenic and alluvial sapphire operations are discussed in detail and rehabilitation programmes proposed for implementation.

Jan 1, 1976

An international raw material partnership, a $164 million 900,000 long ton per year aluxAna plant; an ideal location at Gladstone, Queensland, Australia - this is Queensland Alumina Limited, on stream in 1967 expanded 50 per cent by the end of 1968. Queensland Alumina Limited is the world¦s most modern alumina refining operation which is owned by an international consortium of four companies; Kaiser Aluminum & Chemical Corporation of the United States with 52 per cent; Alcan Aluminium of Canada with 20 per cent; Pechiney of France with 20 per cent; Conzinc Rio Tinto of Australia, 8 per cent. Q.A.L. operates as a co-operative -- the partners do not draw profits from the venture. Instead, each member of the consortium draws alumina in proportion to his share of the ownership. The method of disposal of this alumina is for the partner to decide.

Jan 1, 1969

The control of industrial grinding circuits in Australian concentrators has been practised for many years in one form or another. Some have established simple feedback loops in areas such as fine ore bin feeders (tonnage control), mill pump sump levels (flow control) and water additions (density control). There are also some sophisticated systems which infer circuit product size using complex measurements of mass flaws and water additions in the circuit and attempts are made to control those flaws to produce a constant circuit product size. The inferred size method in Australian concentrators has become firmly entrenched in the last ten years and control techniques involving the use of direct size measurements with reliable on-stream sizers have been Ignored.

Jan 1, 1983