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By Swift J. D

A key parameter affecting the performance of gravity thickeners in hydrometallurgical processing operations is the aggregation state of the feed after the addition of a flocculant. New procedures which measure the settling ratelsize relationship and the size distribution of aggregates in their process liquors have been used to quantify the aggregation state of the feedwell, overflow and underflow streams in a tailings thickener. The data obtained have been related to the thickener's operation and to a change in the flocculant dosage. A comparison is also made between the settling rate/size relationships determined with these new procedures and the mud-line settling rates from cylinder tests.

Jan 1, 1991

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 Saint-Smith J. C

The anode, tank house and wire bar plant and operations are described with particular reference to those features of design and methods which are characteristic of this refinery at its inception.Reference is also made to auxiliary equipment, transport and materials handling facilities.The work of commissioning the plant late in 1959 is discussed and comment is made on the organisation of construction and origin of the equipment.LOCATION OF PLANTThe site chosen for the copper refinery is on level ground adjacent to the junction of the Mount Isa and the main north-south railway lines at Stuart near Townsville, Queensland. Blister for refining is received by rail from Mount Isa. Refined products are taken 10 miles by road to Townsville Harbour for shipment to other Australian ports or overseas, or despatched by rail direct from the plant.Adequate room for expansion was provided to cover copper refining and any associated industry. The layout of future extensions was planned and space reserved for them before detailing the original units of the main refinery.The initial plant also provides convenient storage facilities and is laid out to derive the greatest benefit from prevailing northerly breezes during the humid tropical summer.As far as possible, the working areas are located so that the prevailing winds cool them as they traverse the buildings.These factors are of very great importance since this is believed to be the only copper refinery in the tropics operating with all white labour and in any case the Company set out to provide the best possible conditions for its operating personnel.

Jan 1, 1961

Expansion of the B.H.P. Co. Ltd. mater ials handling facilities, at their Newcastle Steelworks, began in 1964 and continued until 1970. The present complex handles the annual iron ore requirement of some three million tons for the Sinter Plant and Blast Furnaces. Iron ore is discharged from ore carriers and conveyed at rates up to 3,000 t.p.h. to either of two 180,000 ton capacity storage yards, where it is blended using boom stackers. Material is reclaimed from these yards at rates up to 1,000 t.p.h. using a slewing boom bucket-wheel reclaimer and fed to a screening station. Oversize material is scalped out and crushed in a closed circuit cone crusher. Undersize material is sized on double-deck vibratory screens which separate at 1/4in (6mm). The two fractions are blended in two of four 70,000 ton capacity blending yards using slewing boom travelling stackers. Bridge-mounted bucket-wheel reclaimers reclaim the blended piles at 1,000 t.p.h. Fine ore is conveyed to the Sinter Plant and lump ore to a second screening station, for rescreening, before passing to the Blast Furnace.

Jan 1, 1972

By Bhattacharyya A. K>

The Pemali Open Pit Mine is situated in a small island called Bangka in Indonesia. It produces approximately 165,000 m3/year of tin ore with an average grade of 3.67 kg/m' of tin from a primary deposit. The deposit occurs at the rim of a granitoid intrusion within sedimentary beds. The rock formations, all extremely weathered, and the overlying alluvium, are exposed to a rainfall exceeding 3m/year. Serious slope stability problems are experienced at the mine, despite using overall pit slopes of 20¦-29¦, the latter resulting in a stripping ratio of 4:1. This paper outlines a computer based back analysis of a major slope failure involving some 250,000 m' of material which occurred on the west wall of the pit in February, 1984. The findings from the analysis, together with other information, are used to examine the stability of the east wall of the pit, where tension cracks developed later. The results indicate that the large influx of water was the most significant cause of such slope stability problems and a more intensified water management programme would be beneficial.

Jan 1, 1989

By Golding D

The Charters Towers goldfield is located in the centre of a Lower to Mid-Palaeozoic igneous complex where schistose, amphibolite-grade metamorphic rocks were intruded by multiple phases of medium grained granodioritic rocks. Several generations of mafic and felsic dykes also occur. Two distinct mylonites cut all but the youngest granitoids. Gold mineralisation occurs in quartz veins located in brittley reactivated mylonite and in sympathetic fissures in the undeformed granitoids. The gold-quartz veins occur in complex, gouge-filled, 2.5m thick zones, with minor sulfides, surrounded by zoned phyllic and propylitic alteration assemblages. Four main vein systems are each restricted to separate granitoids or contain oreshoots near granitoid contacts. No genetic relationship between the granitoids and the vein systems can be documented. The early mylonitic fabrics and the granitoid contacts played an important role in ground preparation and in the localization of oreshoots. Non mylonitized granitoids also served as favourable hosts for many of the lodes. Whole rock values of 180 of the granitoids range between 6.5 and 7.9 per mil. Hydrothermal vein quartzes have 180 values between 12.2 and 15.7 per mil. Mylonite quartzes have values of 8.4 per mil. Variation in 180 values of quartzes is in part related to granitoid host rock type.

Jan 1, 1987

The mostly submerged New Zealand sub-continent has a complex geological history and an active oceanographic regime that provides opportunities and challenges for offshore mineral exploration. Known deposits include polymetallic Fe-Mn nodules and crusts, polymetallic massive sulfides, phosphatic nodules, titanomagnetitie ironsands and placer gold deposits. Currently exploration interest is high with some 3.5 per cent of the EEZ under prospecting permit or application.   Article 76 of the UNCLOS convention allows coastal states to have sovereign rights over areas of the seafloor that are natural prolongations of the landmass that constitute submerged parts of the continental margin as extended continental shelf. New Zealand has substantial areas of elevated ridges and plateaux beyond the 200 M EEZ that form extended continental shelf. New Zealand has nearly completed a ten year, $44.4 M programme to define its outer extended continental shelf. New Zealand will lodge its outer limits of the extended continental shelf with the UN-appointed Commission on the Limits of the Continental Shelf in 2006, which if accepted, will enclose ~1.8 million km2 beyond the existing EEZ. Ocean Survey 20/20 is a follow-on marine mapping programme to underpin resource exploration and environmental management of the EEZ and extended continental shelf.

Jan 1, 2005

By G K. Robinson, M D. Sinnott

Three-dimensional granular flow models have been run to simulate three types of sample cutters: a cross-stream cutter, a vezin, and a cross-belt cutter. This type of modelling involves solving the equations of motion for large numbers of individual particles as they travel along a conveyor belt and interact with a sample cutter. It allows flows of bulk materials to be visualised and understood. Here we have used spherical particles. These results illustrate some advantages that modelling has compared to physical bias testing: By taking reference samples which are very close to the actual samples, the estimation of bias can be achieve quite precisely with very few runs. (Many Standards about bias testing recommend a minimum of 20 runs, but we have found that five runs generally provide adequate precision.) Potential bias can be divided into two components: the particles which are missed but should have been sampled and the particles which are extra but which should not have been sampled. This more detailed information can provide useful insight. Exactly the same material can be sampled using different sample cutters, thereby avoiding a source of variation that complicates physical testing. Much more detailed visualisation is possible, allowing better understanding of the bulk material flow in various circumstances.

Jan 1, 2005

The combustion characteristics of Australian coals which contain high inertinite have been studied in a laboratory drop tube furnace and a Thermogravimetric Analyser. The pyrolysis chars and combustion residues were microscopically characterised using a modified coal petrography technique. Results indicated that the overall burnout of inertinite-rich Australian coals under pulverised fuel combustion conditions could be generally within a range of 97 - 99 per cent burnout. The studies showed that poor coal burnout cannot be generally related to high inertinite content in the Australian coals. The extent of coal burnout varies from coal to coal and vitrinite as well as inertinite may contribute to the unbumt chars in combustion residues. Combustion conditions had greater influence over char formation and coal burnout than the coal properties. However, under similar pf combustion conditions, coal rank and coal maceral composition had a strong influence over the coal combustion behaviours and final coal burnout. Simple correlations using coal properties may be used but with caution to determine coal volatile release and burnout at high temperature and rapid heating conditions.

Jan 1, 1991

By Rixon LK, Walton KP

Evidence will be presented to show that borescope inspection of mine roofs is one of the most useful techniques available for stability assessments. ACIRL currently has four borescopes, comprising two fibre-optic units of 2.7 m and 4.5 m length and two optical rod units (introscopes) 6 m and 8 m in length. (The 8 m unit is not yet fully operational because of modifications needed to meet safety regulations). Using the fibre-optic units, photographs of hole walls or ends can be taken to record features. Roof lithology and crack patterns can be observed in roof holes from 25 - 60 mm in diameter. Several crack parameters are useful: type, location in the roof with respect to height and lithological boundaries, presence of individuals or zones containing crack clusters and the estimated amount of dilation. These data are readily computer- plotted to form "borescope logs". Provided that the holes remain open, a hole or group of holes can be re-surveyed at intervals to monitor crack development across or along a roadway, for example with respect to an advancing blind-ended roadway face.

Jan 1, 1986

The specification for tender nominated the requirements for ore hoisting and servicing; this showed that one common duty winder could be selected. Foliowing the design of the shaft layout, the merits of fixed or rope guides were compared and the latter selected.The specification called for the supply and installation of the complete hoisting system. Construction of the winder tower and shaft bottom steel work had to proceed while mine development was in progress using the sinking winder and headframe. Guide ropes, winder ropes, and the sky shaft were installed in the shortest possible time, and as the shaft was not equipped with ladder-ways, a second means of access had to be provided.Very few problems were encountered witll the commissioning of the winder, and in the first 2 years of operation the only significant modification was to the circuitry associated witll the moving access platforms.Hoist rope tension checking and adjustment are simple, and non-destructive testing has shown no deterioration of these ropes. The operation of the balance ropes has been very satisfactory but cleaning presented problems in the early stages. Guide ropes have been trouble free and require minimum attention.Normal wear on the PVC rope groove inserts on the winder drum has been negligible.Since the commissioning on fully automatic ·control, the winder has operated with very few, minor delays.

Jan 1, 1969

The Northern Mariana archipelago in the W.Pacific forms a classic intra-oceanic island arc system far from the influences of continental crust. As such it offers an ideal location in which to study many of the problems of subduction-related volcanism. Radiogenic (Sr, Pb, Nd and Hf) and stable (0, S and H) isotope systems have been applied to the question of the possible involvement of components from the subducting slab in arc magmagenesis. The results contrast with earlier studies based upon limited sample suites and suggest that fluids, derived from the slab and enriched in mobile elements, substantially modify the composition of the mantle wedge and contribute to the characteristic geochemistry of arc magmas. Trace element data, including the occurrence of negative Ce-anomalies in the lavas seem consistent with this conclusion. Major and trace element variations within the arc lavas can be modelled in terms of crystal fractionation of a gabbroic mineral assemblage and mixing calculations indicate that this has the approximate composition of PLAG:CPX:MAG:OLIV = 60:25:10:5. This observation is compatible with the widespread occurrence of gabbroic nodules in lavas throughout the arc. Consideration of Rare Earth Element and phenocryst data leads to the conclusion that many of the more basic lavas may be the products of cumulus enrichment. The results of this study constitute a model for magmatic processes occurring in simple island arc systems, and may be generally applicable to other, more complex settings. The recognition of a return flux of material with 'continental' affinity to the mantle, via sediments on the subducting slab, also places strong constraints on geochemical models of crust-mantle evolution.

Jan 1, 1987

In an earlier paper(l) details of a laboratory method of extracting and separating tantalum and columbium oxides from tantalite have been given. In view of the fact that Australia may have need to be self sufficient in this field it was decided to erect a pilot plant for the production of tantalum oxide in the Metallurgy School, University of Melbourne. The plant was designed for treating about 40 lb. of ore in a batch over a period of two weeks, although; because of the sectionalized nature of the process, the capacity of the plant was 40 lb. ore per week.Australia is fortunate in possessing some very rich tantalite and columbite deposits, particularly in the Pilbara District in Western Australia. The ore used in this work was obtained from a small but high grade deposit near Greenbushes, Western Australia, and consisted of lumps, weighing up to 8 lb. each, of almost pure ferro-tantalite with occasional thin veins of the very' rare' mineral stibiotantalite.The main constituents were:

Jan 1, 1946

By Mitchell D. S

BackgroundIn March 1990 Pasminco resolved to replace and increase the capacity of the underground pumping system at the Southern Operations, Broken Hill. The existing pump station was built 23 years ago while the rising main had been in service for 38 years and was subject to frequent failure.The old system was a conventional slurry/clear water separation and multi-stage pumping system. It was inadequate in the following areas:ò insufficient capacity to handle current and expected future flows;ò unable to consistently dewater lower production areas; ò pumping capacity restricted sandfilling rates;ò dirty water dams had insufficient settling capacity and were difficult to de-sludge;ò the operating costs of dewatering were high; ò it was labour intensive; andò it did not offer enough protection to the 25 level loading station.

Jan 1, 1993

By Huber A. L

Research and development into alternate gold and precious metals adsorbents has resulted in the development of a new technology named the AUROSAVE adsorption process (ARGOSAVE'" for high silver con- tent ores). Adsorbents called VITROKELE'" can be tailored for either Gold I (cyanide leach) or Gold III (halide leach) applications. VITROKELE consists of a chemically synthetic adsorbent carried on an inert substrate, often a polystyrene bead. It is suitable for both in- pulp and in-solution use. VITROKELE adsorbent offers certain advan- tages over both carbon and ion exchange resin adsorbents. This paper describes testwork on Australian ores and commercial solu- tions obtained from operating Australian plants demonstrating the kinetic loading characteristics, elution methods and other operating parameters of VITROKELE adsorbent in the cyanide system. Brief reference is made to VITROKELE in the Gold III system.

Jan 1, 1988

As you are all aware, the theme of this con- ference is "International Resources Management". The subject matter of this particular session is "the mineral equation". Looking down the sub- ject matters and individual papers to be presented by other speakers in other sessions over the course of the conference, each particular item scheduled is in fact one of the variables that form an integral part of the total and complex mineral equation. Questions of reserves and resources as related to consumption must be viewed in the light of all those variables. Policy decisions taken by Government and eventually industry in these various fields will in themselves have their own impact on the defining of resources, and their ultimate availability to meet the needs of society by way of consumption. Undoubtedly, by the close of this conference, those of us in attendance will be better informed on the problems that confront the international minerals industry in the years ahead. Hopefully, we will have a better understanding of the views and philosophies of the wide range of participants in the industry-Government, private enterprise, and individuals who ultimately through their per- sonal aspirations in respect of their day to day needs will provide the final determinant as to the scope of the minerals industry.

Jan 1, 1978

In general, modern mining companies all over the world have to face the same economic circumstances as any other part of the industry: considering the tough competition, production and haulage costs must be reduced permanently whereas productivity has to increase substantially in order to remain price-competitive. However, the imposed pressure also offers the chance for consideration of alternative mining concepts, the application of which can result in substantial cost savings and improvements in the quality of the mined material. As one of these alternative mining concepts, surface mining technology offers substantial improvements in productivity. It also influences aspects of haulage, such as safety and speed, in a positive way. The capability of selective mining ties in nicely with the production of small-sized crushed material, the granulometry of which allows the elimination of the primary crusher. Mine operators profit from reduced costs for the maintenance of their haulage vehicles due to reduced wear, a decreased likelihood of accidents and higher average transport speeds. Surface Miners can also be used to cut haul roads into virgin rocks and leave a clean and level surface behind, improving the quality of these created roads. Thus, it is even possible to use ordinary road trucks for transport in mines. The current paper outlines in detail the effects of the surface mining technology on mining and haulage aspects and reports on applications where substantial cost savings could be achieved due to the application of what is also referred to as æsimple mining processÆ.

Jan 1, 2003

By Williams M

Sheet flotation is a new two dimensional column flotation cell that produces continuous spectrum of products. Analogous to a shaking table in its performance and analysis, sheet flotation is a sheet of bubbles rising through packing contained between two walls. Feed enters the sheet at the lower left and the product exit along the top and right edges. Iligh grade materials exit at the top left, middlings exit at the top right comer and low grade waste materials exit at the bottom right. As in the case of a shaking table, two motions are required: up and right. Bubbles furnish the upwards movement for hydrophobic particles, slanted packing the rightward movement for hydrophilic particles. The sheet flotation cells is analysed as a 40 x 40 array of simple cells. In practice, 1000 x 1000 arrays of simple cells may be expected. With larger arrays, excellent separations may be expected. Because there is no recycle, there is no build-up of middlings in

Jan 1, 1993

The Beaconsfield gold mine processing plant is a complex operation and utilises crushing, grinding, gravity gold concentration, sulfide flotation, bacterial oxidation, cyanidation and zinc cementation to recover gold from the partially refractory ore. This paper discusses the challenges, developments and advancements throughout the processing plant since start up, which have culminated in a 25 per cent increase in the mill throughput over the nameplate design and a concomitant gold recovery increase from 75 to 92 per cent. The improvements have been attained via advancements in mechanical integrity, metallurgical review, process control and operator training, resulting in the current operation producing over 630 000 ounces of gold to date.

Jan 1, 2007

By Thompson P, Sharma Y

The paper describes the methodology and results from a study carried out by Telfer Gold Mine to optimise the materials and costs involved in construction of the pad for their dump leach operations. The investigation involved large-scale field testing of five different types of liner and a number of different cushion and drainage layer configurations. The aim was to identify the most cost effective construction methods to allow the final dump height to be increased from 45 in to 60 in without causing significant damage to the liner. The effects of dump height on permeability were also investigated. These methods are described and results presented. The findings indicated that modifications to the existing liner/cushion layer/drainage layer configuration used previously at Telfer would actually reduce overall construction costs rather than increase them despite an increase in overall dump height. Relative construction costs are presented.

Jan 1, 1994