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By Williams C

A stibnite concentrate from Golden Spec (WA) was subjected to a series of tests involving high pressure cyanidation and pressure oxidation followed by conventional cyanidation. The concentrate, whose gold content was 18.1 g/t, yielded only eight per cent of the gold when leached directly by a standard 24-hour cyanidation test. The recovery was increased to only 15 per cent when pressure cyanided under the following conditions: ambient temperature, 2000 kPa oxygen pressure, two hour retention time and 30 per cent w/w solids pulp density. This poor response to pressure cyanidation emphasised the refractoriness of the material. Evidence of the fine distribution of the gold through the concentrate, from measurements of the particle sizing distribution and the gold analyses of the individual fractions, also suggested that this concentrate was highly refractory. Pressure oxidation of the concentrate at elevated temperatures followed by cyanidation yielded recoveries as high as 94 per cent. However a preoxidation treatment under the following conditions was necessary: 230¦C, 2000 kPa oxygen pressure for a period of four hours.

Jan 1, 1992

This paper examines the interplay between longwall support design/geometry features, operational controls and geological features on ground response. Experience from several investigations is used to demonstrate the influence of factors such as longwall support capacity and geometry, setting pressure, coal seam strength and stiffness, tip-to-face distance and hydraulic supply and control system parameters on longwall ground response. These factors are then used to outline the requirements on key controls such as retreat rate and cutting height and their influence on allowable roof convergence. The ground response curve concept as a means to provide graphical representation of longwall support and strata interaction processes is presented. The approach was developed to address the requirement for a practical longwall support evaluation and selection tool that can take account of support load influences such as changes in roof geology or cover depth. An example of the comparison between single pass longwall and top coal caving in a thick seam environment is given to demonstrate the influence of the various factors discussed.

Jan 1, 2005

By Gardner CE

Uranium occurrences and the probable Australian reserves are discussed and the recovery and processing methods used in treatment plants at Radium Hill and Port Pirie, S.A., Rum Jungle and Moline, N.T., and Mary Kathleen, Qid. are reviewed. The broad aspects of the application of nuclear power in Australia are then considered, and those factors of greatest significance are highlighted. It is these factors that are most likely to dictate the future role of nuclear generation in Australia. In commenting on private industry applications, the paper emphasises that each case must be considered on its own merits, and a warning is given that general statements can be misleading. In the long-term situation nuclear power is considered to be capable of playing a leading role and the discussion covers desalination and high load industries although short term applications appear difficult to justify. In non-power applications for nuclear energy reference is made to isotopes and the uses of nuclear devices in mining and civil engineering with a pertinent comment on safety.

Jan 1, 1970

The nickel refinery at Yabulu consumes an average of 118,000 kg/h of low pressure steam in stripping operations to-recover ammonia and carbon dioxide from product liquor and ore tailings streams. The steam used in the stripping operations is produced from the 25 MW power generation plant at the refinery. The back pressure on the non condensing steam turbines is maintained at 60 kPa.Studies have been carried out to determine the optimum amount of steam required to be generated for stripping operations. When steam production is increased, the product liquor flow from thewashing thickeners can be increased. This results in improved washing efficiency of the thickeners and therefore improves the plant nickel recovery. A computer thickener wash model was used to predict nickel recoveries at varying steam consumption rates.The studies have shown that in most plant situations, it is not economical to-generate more steam than that already available from existing power production.The studies also highlighted the necessity to use all steam generated from power production at all times to maintain maximum nickel recovery.

Jan 1, 1985

By Abdalla MH

The deformation resulting from the presence of a tunnel may signifcantly affected, nearby structures and need to be considered during design of both tunnel and structure. The aim of this paper is to study the effect of different factors which may affect the interaction between the tunnel and the str- ucture. These include; the depth of both tunnel and foundation level of the structure ( z and t ), distance between C.L. of tunnel and loads, breadth of the loaded area, Diameter of tunnel and lining of the tunnel. The problem is studied as a two dimensional plane strain model by the boundary element technique. The results of this study indicated that the presence of a cavity/tunnel increases, in general, the vertical displacement on the ground surface and at the foundation level as well as the horizontal and vertical stresses in the cavity/tunnel level. The effect of eccentricity is increasing as e/D decreasing. For pile foundation there is a quite different- influence of the presence of cavity/tunnel in both cases of friction pile and end bearing pile type of foundation.

Jan 1, 1987

It's a great pleasure to be here today, for a whole series of reasons. First of all, when I first went to Perth back in 1972, I shortly afterwards began auditing and one of the people to pick on me when I audited the West Australian Newspaper at that time was Patrick O'Connor's father. One way to win a person across when you're auditing and getting picked on is by showing an interest in their children, so I did that and employed Patrick in our firm. In those days, conflicts of interest didn't occur. When I started Normandy, Patrick was one of the first people I went to get to work with me. He very unwisely chose to leave at one stage and you can see he's done extremely well by not staying with us. So it's lovely to have you here today, Patrick. The difference between Patrick and me, now, is that he's kept his hair, and if you're tall enough you can see I haven't.

Jan 1, 1997

The use of pipeline-c to carry crude'oil and petroleum pro-ducts is a reliable and economic*Way to transport large quantities of oil. The length and size of these pipelines have continued to grow throughout the world as the demand for petroleum has in-creased and as the price of other transportation-methods has risen. At the present time pipelines 'can move a barrel of oil a distance of 100 miles at an average cost of ,80.06 U.S. dollars.The major elements in pipeline design are discussed. Methods of calculating pressure drop and horsepower requirements are pre-sented. These are variations of standard equations.in which the elements of each equation are expressed in terms common to the petroleum industry. Major equipment is discussed., particularlyas it relates to operation and economics.Cost data are presented to aid in preliminary economic ana-lysis. Curves illustrate the cost of oil transportation at flow rates between 10,000 and 500,000 barrels per day and permit the selection of pipe diameter-which will result in minimum operating costs.

Jan 1, 1962

German coal mining suffers from rock temperatures up to 600C which are the same as in South Africa at 3000 - 4000 m of depth. Therefore cooling plants have increased in the last decade and today a cooling power of nearly 200 MW is installed in the total Ruhr District. Cooling a mine is a little bit different from cooling a bottle of beer in a refrigerator in the kitchen because the heat taken from the bottle of beer is delivered to the kitchen some centimetres away; in mining the cooling-problem is more difficult: here the bottle of beer corresponds to the airflow at the coal face and the kitchen to the surface, So it is necessary to transport the heat or the "coldness" a long distance. In the address by Ieuan Morris some systems for transporting heat from the coalface to the evaporator of the cooling machine and further from the condenser of the machine to a return airflow were described. The following is a short idea of the way this problem is treated in Germany.

Jan 1, 1983

The environmental and social responsibilities of the mining industry have long been recognized by the industry itself, but during the past decade it became one of the main targets for the more radical members of the community. This came as something of a shock to an industry which had always considered that it had acted responsibly within the standards of the day. As far back as early 1968, the Australian Min- ing Industry Council (AMIC) was clipping from newspapers the odd letter written by environmen- talists and critics of mining activities. In those days every such letter was carefully studied to ensure that AMIC, if not having the answers, at least had an understanding of the types of argu- ments then starting to be used against mining activity and in favour of environmental preserva- tion. Within 18 months, the infrequent letter to the editor had become a flood of such letters and feature articles, and the environmentalists' attack on mining activities had been launched in all its Vehemence.

Jan 1, 1978

By Voermans F. M, Hoyle M. W H

The Archean geological sequence in the West Pilbara region (Fig 1), a deformed greenstone volcano-sedimentary succession regionally intruded by layered mafic/ultramafic lopoliths, batholithic granites, granite stocks and transected by swarms of dolerite dykes, has prompted several companies to search for a variety of base metals and and platinoids (Fig 2). In the first instance, detailed aeromagnetic surveying was completed, producing patterns of marked magnetic anomalism which proved substantially successful in the demarcation of areas warranting geological reconnaissance and detailed follow-up. Revelant to this paper were the obvious magnetic features overlying outcropping and buried mafic/ultramafic bodies which ultimately were proven to be host to Ni-Cu sulphides, pgm, Ti, V, Cr and, more recently, Ag and Au mineralisation. Routine stream sediment, soil sampling and ground geophysical techniques of the day appear, in most cases, to have been adequate in the detection of mineralisation, except in the case of Radio Hill massive sulphides where the Turam E.M. (1972) signal essentially failed to detect the blind conductor (Peters, de Angelis 1987).

Jan 1, 1988

By Davison GR

The cost of drilling consumables is always a large component of any mine budget. It is important that this cost be carefully examined with a view to reducing the overall cost per inetre or at least minimising its escalation.At Renison it is considered that the only way to ensure drilling costs do not rise unduly is through a total system of control from purchase to disposal.In 1979 extension of an existing drill supply service contract was carefully examined and abandoned in favour of a hybrid system. This system is providing a great deal of control over the use of drilling consumables and has maintained a relatively constant cost per drilled metre over the last five years.Current consignment stock contracts for drilling consumables are strictly specified by the Technical Services section of the Mine Department and consumables purchased under these contracts are distributed and refurbished/sharpened by a contractor.The total result of this package is individual drilling items that achieve the best cost per metre and careful distribution and maintenance to ensure maximum life.

Jan 1, 1985

By Fisher AEJ

On Sunday morning 7th November, 1976, at approximately 2-25 a.m., smoke was discovered issuing from the 1912 m long belt drift at Appin Colliery. A Clouth steel cord rubber belt approximately 940 mm in width had been installed in the drift in 1963 on the basis that no fire resistant steel cord belt was then available to operate on a single lift at the load and on the 160 gradient of the drift. Investigation showed that the belt drift was on fire and the usually downcasting drift was upcasting. Immediate fire fighting and rescue operations were instituted and the drift was sealed off. High expansion foam was pushed into the drift from the surface and the fire was brought under control. Recovery work resulted in the fire being put out and the drift open for walking traffic by, S-P0 am., on Wednesday 10th November, 1976. lie experience gained during the fire fighting and recovery operations led to recommendations in regard to future use of high expansion foam.

Jan 1, 1981

The growth in the nickel market and the price increases predicted in 1970 have not mat-erialized. Several plants have been construct-ed, particularly to treat lateritic ores. A spectacular increase in cost of energy and the escalation of capital costs have led to severe economic difficulties on the part of many nickel producers. Several of the nickel prod-ucers joined together to form a Nickel Develop-ment Institute in 1984 with the prime objective of improving nickel markets. Most producers have taken exceptional action to cut overall costs as well as unit costs. Another organiz-ation made up of nickel producers, NiPERA, was established in 1980, to study and take action on problems of nickel in the environment and especially in the workplace.Ion exchange, and particularly continuous ion exchange, has been developed into a reli-able commercial unit operation in the last dec-ade. An example of how ion exchange combined with hydrogen reduction can be integrated into a Caron type reduction roast ammonium carbonate leach process for the recovery of nickel from laterites is discussed.

Jan 1, 1985

By R H. Eric

Surface wave formation induced by a high-strength submerged jet in a bottom blown metallurgical vessels has been studied experimentally by using one-seventh water model of CLU (Creusot-Loire Uddeholm) reactor with two different tuyere configurations. Experimental results have been discussed in terms of the wave period, wave frequency and wave amplitude with respect to air injection rate and tuyere configuration at a 0.23 m bath height. The results from high speed photography observations displayed the formation of rotating surface waves which circulates within the water model. It was found that the frequency and the amplitude increased with gas injection rate. The wave period for off-centre nozzle orientation was found to be lower than those of the centre configuration. The experimental results also showed that the frequency of a rotating wave increases when the tuyere orientation becomes off-centred . The predicted amplitudes were in very good agreement with the experimental values over a range of gas flowrates between 0.00599m 3/s to 0.01081 m 3/s.

Jan 1, 2000

In-pit crushing systems have been known in the mining industry for many decades. The question whether in-pit crushing is a viable option has often been asked. More than 200 mobile and semi mobile crushing systems have been installed worldwide at various locations and applications. Economic pressures have forced mine operators to reconsider the use of a conventional truck-shovel operation and have contributed enormously to the development of in-pit crushing and conveying systems. The in-pit crushing concepts have varying mobility capabilities. These range from fixed, stationary crushing plants to semi-mobile and fully mobile crushing plants. All these systems are operated in connection with a conveying system. In general in-pit crushing systems have technical and economical cost advantages over truck-shovel operation, particularly as mine capacities increase and mines become deeper. The integration of an in-pit crushing system represents a significant up-front capital investment and the mine is only able to depreciate the capital investment over a sufficient mine life including plant capacity to realise the benefit of the much lower operating cost.

Jan 1, 2003

By Koginmo V. I

The concentrator at Bougainville Copper Limited has an annual throughput of 48.2 million tonnes/year producing approximately 175,000 tonnes copper, 16.1 tonnes gold, and 50 tonnes silver. Conventional three stage crushing and screening are used to reduce run of mine ore to an average product d80 size of 6.7mm. The primary objective of the crush- ing plant is to provide a continuous supply of ore to the 12 primary grind- ing mills via an intermediate 300,000 tonnes capacity stockpile. Since ball mill performance improves with decreasing mill feed size, the crushing plant continually strives to produce the finest possible product for mill- ing. This has been achieved by increasing plant availability and total installed power, and improving crusher manganese liner life, screen cloth life, and plant operating practices. A recent innovation was the installa- tion of a 35 million tonnes/year preconcentration screening plant in Janu- ary 1987 to recover high grade fines from low grade run of mine ore types in which the mineralisation occurs preferentially along fracture planes in the parent rock.

Jan 1, 1988

By Joussemet R, Fabre F

The paragenesis of the Escuzar Mine (Andalusia-Spain) comprises: ò major constituents: celestite and carbonated minerals (abundant calcite and less frequent strontianite). ò minor constituents: sulphates (gypsum and anhydrite), clays and some iron oxides and hydroxides. The average content is at about 60 per cent SrSO4. Since liberation size was fine (from 30 to 50 ¦m), the flotation method was chosen. Laboratory batch tests have shown the relevance of using alkylsulphates with as long as possible hydrocarbon chains. The recovery obtained led to an expected 95 per cent SrSO4 concentrate with nearly 70 per cent recovery. Pilot plant tests (160 kg/h) have confirmed these results and attained a recovery of more than 65 per cent of a 96 per cent SrSO4 concentrate. Extrapolation to the industrial scale (14 t/h) has been successfully carried out : up to 600 t of a concentrate at more than 95 per cent SrSO4 has been obtained. Non optimised recovery has already reached 60 per cent for a 97 per cent SrSo4 concentrate.

Jan 1, 1993

Gravity concentration of tin at Renison Limited uses tables and spirals to treat the various coarser fractions produced from sulphide flotation tailing. An acceptable final tailing cannot be made from one pass over the tables and spirals and therefore the tailing from these separators is reground and combined with the sulphide flotation tailing as the feed to the classification section. The gravity section became increasingly overloaded in the years preceding 1976 due to efforts to maximize tin recovery to the gravity concentrate. In April, 1976, two 2DSV Reichert cone concentrators in series were installed to treat the table and spiral tail- ing stream, prior to regrind, to scavenge a small tonnage of hard, coarse low tin grade material for rejection to final tailing. Gravity section loadings were decreased markedly, allowing operator attention to be directed more to table performance than to spillage collection. An increase in mill throughput of approximately 15% was possible following the commissioning of the Reichert cones. The cones are currently operated to make the minimum tonnage of tailing consistent with reasonable- gravity section loadings.

Jan 1, 1978

A major problem in the continuous casting of aluminium killed strip steel is the incidence of black and grey lines in the strip surface caused by the alumina inclusions. One place for limiting the number of alumina inclusions is by providing favourable fluid flow conditions in the ladle so that the inclusions float out to the surface or adhere to the ladle wall. In laboratory equipment 20 kg of steel was melted in an alumina crucible of 14 cm diameter in an induction furnace. Deoxidation was carried out while the melt was constantly stirred by argon bubbling. Bubble frequencies were measured at the lance tip using a microphone technique. High speed cine photo- graphy was incorporated to measure melt top surface velocities. Experimental results indicate that the rate of removal of inclusions is a function of both the gas input and the power input. However due to unfavourable surface area to volume ratio, reoxidation of the melt took place. Some other experimental difficulties in working at high temperatures are also discussed such as lance design, melting arrangement and sampling techniques.

Jan 1, 1984

By Unver B

Longwall advance mining is still the predaninant system of coal extraction in the U.K., contribiiting to sane 70 % of underground coal production. Gate roadways providing access to a longwall advancing coal face are maintained adjacent to a rib pillar under high strata abutment pressures and the caving rock mass. It is very difficult to realistically model such access roadways using mathematical or numerical techniques and hence, predict roadway closure. For the past 15 years, a research group in Nottingham University has been engaged in the study of longwall gate roadway stability using observation methods. Gate roadway deformations have been measured in 224 gate roadways and a comprehensive data base has been established. The paper describes the statistical analysis of this database and presents sane. predictive equations which will enable a forecast of the gate roadway closure to he made. Further field work to validate these equations. is described together with an error analysis. The results are very promising and indicate that it is possible to predict gate roadway closure in the U.K. within practical limits of Accuracy.

Jan 1, 1986