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The Amacan Copper Project was constructed in the Philippines by a Finnish-Filipino Consortium during the years 1979 - 1982. The project involved a turnkey contract for a mine and a concentrator to process 25 000 tonne per day of porphy- ritic copper ore at a grade of 0.45% Cu. The orebody is located on Mindanao, the southernmost island of the Philippines, in rugged, mountainous terrain approximately 1 000 m above sea level. The adopted design principle was based on an efficient, straightforward installation utilising a minimum number of items of equipment each with high unit capacities. The consortium faced many problems which resulted in lengthy delays in construction and finally led to the client taking over responsibility for the completion of the project. The concentrator was successfully commissioned in July 1982.

Jan 1, 1986

By McCarthy P. L

With production at Olympic Dam scheduled to commence in June 1988, it has been necessary to install a complete underground ore handling system capable of removing two million tonnes of material annually from the mine. The system comprises mucking from stope drawpoints, truck haulage to underground storage, primary crushing, conveying and hoisting. On the surface, material is conveyed to stockpiles at the Metallurgical Plant. Mining of the numerous special excavations within the system was incorporated into the mine's ongoing development program prior to the underground construction phase. Utilisation of a decline from the surface enabled versatile construction equipment to operate at the underground sites as well as simplifying the transportation and delivery of construction Materials.

Jan 1, 1988

By Hagen G, Uhlig H

In the Federal Republic of Germany the thermal environment in underground coal mines has deteriorated progressively over the past years. The number and capacity of refrigeration plants have increased correspondingly. In recent years high capacity spray coolers have been used in addition to conventional cooling coils.

Jan 1, 1988

By Weir D. R, Doyle B. N

The Sherritt Zinc Pressure Leaching Process is based upon the direct pressure leaching of zinc sulphide or lead-zinc bulk sulphide concentrates to produce zinc sulphate in solution and elemental sulphur in the leach residues. The zinc sulphate solution is compatible with conventional purification and electrowinning technology. The pressure leach residues can be treated for the recovery of elemental sulphur, lead and silver. With the conversion of sulphur to the elemental form, zinc pressure leaching allows zinc winning to be independent of sulphuric acid production. Direct pressure leaching of zinc sulphide concentrates was started commercially in October 1980. Continuing research and development studies have defined various pressure leaching configurations for integration with existing roast-leach operations, for grass roots plants, or for plants which are to have the roast-leach section completely replaced. These studies have included the treatment of zinc concentrates from various Australian producers and the development of process flowsheets for potential applications in Australia.

Jan 1, 1989

The collapse of the I.T.C., the subsequent fall in the price of Tin, and the lifting of quotas saw the Renison concentrator resuming full seven- day operations at maximum capacity in 1985/86. Performance was sus- tained in terms of grade and recovery, and in some areas improved, over this period. A further challenge was declining head grades, and the need to treat higher proportions of less amenable ore types. The complexity of the flowsheet and the method of mining and ore handling predisposes the process to unstable operation, and solving this problem comprises a major component of the current development effort. The concentrator has an imbalance of capacity between processes, and excess in some areas is being adapted to enhance the capacity of others. Magnetic susceptibility of various minerals is being exploited to greater effect. Significant performance gains are achievable by improving exist- ing unit process efficiency, particularly in grinding, gravity processes and Cassiterite Flotation. This paper reviews the metallurgical developments, both recently implemented and planned for this year, which have contributed to main- taining Renison Limited in a competitive position in the post I.T.C. Tin industry.

Jan 1, 1988

By Hughson B

A multi-wire borehole instrumentation system was used to monitor strata movement caused by a retreating longwall face at the Ellalong Colliery, situated in the Lower Hunter Valley in New South Wales, Mechanical anchors were placed at various horizons in the borehole which extended from the surface to the extracted coal seam. The vertical movement of the anchors was monitored during mining. The zone of major disturbance was confined to 13 times the extracted seam thickness above the seam. The average dilation of strata in this zone was 6 per cent. Above the caving zone, the tensile strain was under 2mn/m except at one location, where it was `xmi/m. The subsidence trough under dynamic conditions was flatter than that under stationary conditions. The subsidence also depended upon the extent of strata fragmentation prior to undermining.

Jan 1, 1987

By Mckenzie CK

Delay scatter, although widely recognised, has rarely been studied with the aim of critically reviewing blast designs. With current trends towards increased deck charging, and the effect on the number of separate delays in blast designs, delay scatter is shown to have a rather profound influence on the control of initiation sequence and the ability to successfully con- duct pre-splitting and smooth blasting. Determination of realistic delay scatter distributions is the first step towards application to blast design. Delay scatter must be evaluated in terms of deviation from the nominal time, not in terms of deviation from the batch mean, since the latter is not usually known without specific testing, requiring accurate timing instrumentation. Computer programs using Monte Carlo simulation can then be developed to investigate the probabilities of out-of-sequence initi- ation or near-simultaneous initiation within any specified interval. The procedures have been applied to both production and development blast designs in Australia and Chile to improve initiation sequence control and to rationalise and simplify blast designs.

Jan 1, 1988

By Fry P. R

Dragline operations have played a major and successful role in coal mining around the world for more than 30 years. Because of this long history, many of the operating draglines are reaching an age where maintenance and downtime costs are prohibitive, and decisions need to be made to either replace or refurbish them.In the current economic climate, refurbishment is a popular choice and this usually involves major structural repairs above and below the roller circle, together with replacement of the roller circle components. Often, the dragline tub is also replaced by a completely new one.

Jan 1, 1992

By Marshall GA

Structural fatigue damage of haul truck frames is a costly problem associated with the operation of large mine haul trucks. A monitoring programme is described which has been instigated to measure stresses in the frames of haul trucks under actual mine operating conditions. The instrumentation used and methodology employed in the computer analysis of the results is briefly described. The results of the monitoring programmes are reviewed, and the effects of various factors affecting structural fatigue damage of three common types of rear dump truck are considered. Factors discussed include the effects of haul route features (for example shovel, dump and crusher areas); the effect of operations such as turning, braking, loading and dumping; the influence of payload; the effects of malfunctions in suspensions; and the influence of haul route surface quality. It is shown that with respect to payload, while structural fatigue damage is increased with payload, the structural damage per unit of payload does not change significantly for moderate increases in payload above the nominal value. Finally, on the basis of these results, recommendations are made for haul route design and operational practices which will increase the structural fatigue life of haul truck frames.

Jan 1, 1986

By Doyle R

Underground operations commenced at Tower Colliery in late 1978 and the early prevailing mining conditions in the worked seam were considered poor as a result of high stress and geological disturbances. This suggested that outbursting activity may be a possibility. The colliery has since recorded a total of 13 individual outburst incidents, all of which have been associated with the same dyke and strike-slip fault zone. This paper depicts the geological conditions and presents the results of investigations undertaken at the time of these outbursts.

Jan 1, 1986

By Baczynski NR, Fagan MJ

A 3050m long section of a 1.65m internal diameter tunnel is presently under construction in the Brisbane area by means of the pipe-jacking method. The soils along the alignment had been deposited in a deltaic/estaurine environment and rapid changes in soil type occur. The tunnel passes beneath several extensive bodies of surface water. Groundwater problems have been experienced with tunnelling through alluvial sands and gravels. Details of the ground conditions, the pipe-jacking method used and tunnelling experience are discussed in this Paper.

Jan 1, 1987

The equity market is now very much within a global village environ- ment, with various exchanges acting as agencies for the big casino. In this predicament, mining companies, who provide the most extensive, but relevant risk assessment information, will be best placed for favoured treatment by potential international investors: But what risk assessment information in summary form can be provided to support a resource/reserve statement? Even more importantly, does "objective" data exist, whose trends will support a resource/reserve state- ment? A prime need of the informed mining investor is to determine whether or not the resource/reserve statement is believable? But more importantly will it be realised? While the implications within the text of the majority of reports on resource/reserves suggests that the estimates are conservative, the record indicates that very few estimates are. In fact, to date, reports claiming to be conservative in respect of the overall grade estimate at a specfic cutoff have not reflected the realised grade at the stated cutoff; it has been more common for the realised grade to be lower than implied by the resource/reserve statement. Further, it is not uncommon for penalty elements to be understated and these components are rarely incorporated within resource/reserve statements.

Jan 1, 1988

By McGuckin P. H, Logan A. S

The BHP Minerals' Cannington silver-lead-zinc deposit is located approximately 190 km south-east of Mount Isa. The deposit, is hosted by Proterozoic rocks beneath a thin cover of younger sediments, and contains a total estimated resource of 45.3 million tonnes at 11.1 per cent lead, 4.4 per cent zinc and 500 g/t silver. The deposit is separated by faulting to form a shallow, lower grade Northern Zone and a deeper, higher grade Southern Zone (Roche, 1994). Contract development of an exploration decline to test mineralisation in the Southern Zone commenced with the excavation of a boxcut in August 1993. The complex variably deformed Proterozoic sequence interpreted from drill core and intersected in the exploration decline has required a high level of practical rock mechanics input to achieve: ò appropriate support designs, ò a high quality of installation, and ò required development advance schedules. The Norwegian Tunnelling Index (Q System) in conjunction with regular face mapping is used as an operating tool to assist in decision making for ground support. Line mapping, discontinuity analysis and wedge assessments are conducted routinely to optimise ground support requirements in the decline, intersections and all other underground excavations. Throughout the project, an emphasis has been placed on developing a strong working relationship with the contractor to achieve quality assurance program targets.

Jan 1, 1995

Investigation on Sheelite Floatability by Particle Size Fraction

Sep 13, 2010

By Woodcock J. T, Millett R. N

It was shown that manganese dioxide could be used as an oxidant in acid thiourea leaching of a gold ore. Manganese dioxide could generate high redox potentials and was as effective as hydrogen peroxide in the leaching process. Results obtained under closely controlled leaching conditions confirmed that high redox potentials enabled faster dissolution of gold to be obtained but led to extremely high reagent consumptions (thiourea, acid, and manganese dioxide). Additions of sodium sulphite solution in an attempt to lower thiourea consumption by reducing formamidine disulphide back to thiourea were only marginally successful. Although thio- urea consumption was slightly decreased, the consumption of acid and manganese dioxide was substantially increased and there was no net benefit in using sulphite. Tests in which a single addition of mangan- ese dioxide was made before addition of thiourea minimized overall reagent consumption and gave only a slightly lower dissolution rate of gold. This is a promising technique for further Investigation.

Jan 1, 1987

By Walton M. C

A combination of flotation and smelting technologies is proposed as a cost-effective means to maximise the revenue of base metal operations. The proposed treatment route breaks the grade - recovery nexus associated with the treatment of ores exhibiting difficult mineralogy in conventional plants. Aspects of the two technologies are reviewed and typical capital and operating costs presented. A significant improvement in revenue is demonstrated in a worked example, where a copper-lead-zinc operation is examined in terms of the conventional and proposed treatment options. For the selected ore, the net smelter return per tonne of mill feed improved 57 per cent, from US$89.70 to US$141.10 with the proposed treatment option. This represents an additional US$51.4 million in annual revenue. Metallurgical operating costs increased by US$20.12 per tonne of mill feed for an incremental capital requirement of US$30.3 million for an existing operation.

Jan 1, 1992

By Phillips J. T, Hutton W. A

This paper discusses why Argyle Diamonds adopted thickened tailings disposal in 1985 and how the system was developed over the next seven years. A wide ranging review of the thickened tailings disposal system and the tailings deposit it was producing was carried out during 1992 and 1993. The results of that review led to the abandonment of thickened tailings disposal at Argyle because of serious concerns about the stability of the resultant tailings deposit. The exposure to the risk of liquefaction and an assessment of the consequences if this happened to the thickened tailings deposit are shown. The criteria for selecting the new tailings disposal strategy are then described. The final section of the paper discusses the management strategies that have been put in place. These are designed to: ò reduce the risk posed by the thickened tailings deposit to an acceptable level; ò safely store tailings to the end of mine life; ò produce a land form that can be decommissioned to the satisfaction of Government regulatory bodies.

Jan 1, 1996

A brief descri;tioki is given of nuclear power reactors and their fuels. These fuels are made from a variety of uranium compounds such as uranium dioxide, and uranium carbide as well as uranium metal and its alloys. The various processes used to produce some of these compounds from yellow cake are outlined. Using the natural uranium, heavy water reactor by way of illustration, fabrication of fuel elements is dis- cussed and the characteristics of U02 powder required for this partic- ular fabrication are indicated. The flowsheets and equipment presently in use overseas for production of this type of U02 powder are described. Possible areas where improvements might be made to this conventional process are enumerated and some details are then given of the programme of work which has commenced at the A.A.E.C. Research Establishment to gain experience in the general field of nuclear grade UO20

Jan 1, 1968

By Klinefelter G

The United States Steel Mining Co., Inc. recently experienced a major mine fire at the Cumberland Mine. This mine is located in Greene County, Pennsylvania, U.S.A. and is mining a high volatile bituminous coal seam (Pittsburgh Seam). The mine fire was success- fully controlled and extinguished without loss of life or serious injury to any miner or mine rescue personnel and finally reopened within 40 days of its inception.

Jan 1, 1988

Ore reserve estimates form a basis for strategic mine planning at Argyle Diamonds open pit and alluvial operations. Most ore reserve statements are mainly concerned with resource tonnage and grade. Because diamond deposits are low grade, high value resources, diamond quality ($/carat) is also an important parameter. Relatively large variations in quality and/or grade can occur. These variations must be taken into account before the resource potential can be fully assessed. Computers (HP9000 and PC's) are utilised to compile resource inventories. Resource inventories are then ranked on an economic basis. This paper discusses the methods used to compile resource inventories and explains how these are then used to present ore reserve estimates in terms of resource potential.

Jan 1, 1990