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By Segnit ER, Boow J

The start up operations of Western Mining Corporation's Kalgoorlie nickel smelter encountered troubles due to the high magnesia content of the concentrates. The flash smelter slags, with higher than normal magnesia content, had a much higher melting point than the normal low-magnesia, predominantly fayalite slags usually produced in nickel smelting. Investigations were made of the structures, melting points and viscosities of the Kalgoorlie smelter slags, as produced, and with additions of silica or lime.

Jan 1, 1980

By Nag D. K

King Island Scheelite is a wholely owned subsidiary of Peko-Wallsend Ltd. The company works two underground mines near the southern end of King Island at the western approach to lass Strait, 240 km south of Melbourne. (See ^igure 1).

Jan 1, 1981

By Burford B. D, Johnson N. W, Rohner P

Under design philosophy, the Hilton concentrator produced lead, zinc and LGM (lead plus zinc) concentrates. The LGM (Iow grade middling) concentrate was produced by combining coarse middling streams from the lead and zinc circuits, regrinding and subsequent flotation. Mineralogical examination of the zinc circuit middling stream prior to regrinding suggested that production of zinc concentrate from the zinc circuit middling stream should be possible by rearranging existing plant equipment. Laboratory testing of samples of plant products, however, showed that regrinding combined wi th the usual reagent suite was nO1 sufficient to produce a zinc concentrate of the required specifications.Examination of the process water highlighted a problem with dissolved salts in the circuit water, which was solved by in-circuit precipitation of the dissolved ions with soda ash. Implementation of the procedure in the concentrator effectively transferred to the zinc concentrate all sphalerite previously recovered to the LGM concentrate.

Jan 1, 1994

By Young DJ

Gold mineralisation at the Hamata prospect is related to a series of stacked pyrite and quartz-pyrite veins associated with a number of shears which strike N to NE and dip E. Mineralisation is contained entirely within the Morobe Granodiorite close to the intersection of the Upper Watut Fault and some younger NE to SW striking faults. The prospect was originally detected in 1987 by a regional stream sediment sampling programme. Subsequent mapping and sampling outlined an anomalous zone approximately 900m long by 300m wide. Drill testing has indicated a resource of 46Mt at 0.9 g/t Au.

Jan 1, 1991

By Martin T

High methane content of the medium volatile metallurgical coal mined from the Coal Basin mines causes very difficult mining conditions. Rapid desorption into the mine ventilation system limits coal production, requires huge fresh air quantities and creates mine safety problems. In workings deeper than 2000 ft (600m) gassy coal and heavy cover create outbursting conditions. Cross-measure methane drainage has reduced ventilation requirements on advancing faces, but degasifica- tion of virgin coal is needed to improve mining Conditions.

Jan 1, 1982

By Phelan JM

Poor selectivity in the separation of two sulphides generally arises because the flotation characteristics of the coarse sizes of the valuable mineral and finer sizes of non-valuable minerals are identical. Separat- ing the pulp into two size fractions at a specifically determined cut size and conditioning each size fraction with its own optimum reagent addi- tion is known to be helpful in improving such selectivity problems. The performance of the zinc section of the complex ore circuit at Wood- lawn Mines has been analysed in detail. The selective recovery of zinc was found to be a problem in zinc/pyrite separation. However, atypi- cally, the separation problem was between coarse zinc and coarse, not finer, pyrite. In spite of this the use of separate conditioning has effected significant improvements in rougher concentrate. Selectivity (and hence grade), overall recovery and flotation rate have all been enhanced. Dis- appointingly, coarse zinc recovery was not increased but, with careful optimization, this might be achieved without sacrificing the gains already realized. The technique of separate conditioning clearly has general application in other circuits where selectivity is a significant problem.

Jan 1, 1988

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 Reeves T. J, Hansen J. Y

Dense medium cyclone theory, supported by extensive experimental and plant-scale evidence, demonstrates that medium rheology (stability and viscosity) substantially affects cyclone performance in mineral applications.Two instruments have therefore been developed to allow medium stability and viscosity to be-monitored in the plant environment. The instruments are described, and examples are given of their application in full-scale plants.

Jan 1, 1989

The screening of iron ores, sinter and coke, and investigations undertaken to improve screening efficiency and cloth life are discussed. The major modifications to coke screening proposed with the construction of No. 7 coke ovens battery are briefly described. The major problem areas were identified as screen cloth blinding and pegging, feed presentation and screen overloading. Blinding and pegging have had a significant effect upon screening efficiency with the screening of sinter, coke breeze and wet iron ores in particular. Pegging can be reduced or eliminated by the correct selection of aperture size and shape, screen excitation and slope, and screening medium. Blinding encountered with wet coke breeze was a particular problem in which no significant progress was made.

Jan 1, 1984

By Ariti J

The mineralogy and extractive metallurgy of platinum and palladium in ores and residues is examined and the relative reactivity of Pt, Pd, PtS and PdS in cyanide and chloride media at 20¦C is discussed. Electrochemical measurements establish that Pd is readily leached in chloride media but more slowly in cyanide media due to a passivating PdO film. The passivating oxide film on Pt prevents leaching in either system at ambient temperatures. The results of leaching Au, Pd and Pt from an iron oxide residue obtained from the Sherritt Gordon Process using CN/air and Cl-/H202 are compared. It appears that passivation is overcome either by roasting at ?600¦ or by leaching at >_100¦C.

Jan 1, 1991

By Nevolina VG, Zakharova IB

The results of a study on the flotation of baddeleyite and associate minerals are presented, together with effective flotation reagents. Detailed microcrystallomorphological analysis of the benefication products were made to find out the features of distribution of different baddeleyite generations between froth and chamber products. To reveal the dynamics of interaction of technological properties of minerals with their morphology and constitution, a method of onthogenetic analysis was used. It is well known that the difference between technological properties of the particles of the same mineral depend greatly on its genesis, but also the relation is direct - by means of constitution (habit). Thus, flotation behaviour of minerals depends on morphology microinclusions, distribution of impurities, dislocations and physical properties of individual particles. The microrelief of baddeleyite grains and crystals from froth and chamber products was studied with an electron scanning microscope. Chemical composition was determined by means of laser, microprobe and chemical analyses. The difference between baddeleyite generations, their distribution in benefication products, and the effects of grain sizes, number of inclusions and chemical compositions were valuated. Conclusions on baddeleyite flotation properties were made. Mineralogical study on eudialite grains from rough ore and eudialite concentrate was carried out. The interrelation between eudialite and associate minerals and negative effect of aegirine on technological properties of eudialite were revealed as well.

Jan 1, 1993

By Sauer P

The paper deals with the method of operat- ion, types of construction and sizing of screening machines as well as the selection of suitable screen decks. The application of novel screening mac- hines in hard coal preparation plants is explained in detail by way of examples.

Jan 1, 1984

By Matsushita Y, Maeda M, Sano N

The present study was carried out to explore the possible separate recovery of iron and phosphorus (as gas) from BOF slag using graphite crucibles or graphite powders in the presence of a tin bath. The last is consider- ed to enhance the activity of phosphorus in iron reduced from slag or not to absorb the phosphorus vapour readily. When the slag was reduced in a graphite crucible in contact with a tin bath, the phosphorus reduced from the slag was carried away in CO explosively generated by the reduc- tion of iron oxide. When graphite powder was used as the reductant instead, 78% of the phosphorus was removed from slag, only 3% of which was absorb- ed into the tin bath. The rest left the system as gas. Gaseous dephosphorization depends on the area of contact between slag and reductant as cll n.u the amount of the latter. the reduction behaviour was directly observed, using an X ray transmission technique, to conlirm the reaction mechanism.

Jan 1, 1980

Rajor intrusion-related Cu and Au dep- osits along the Cordilleran-type central Andean margin and in the western Pacific island arcs constitute a series of discrete, linear belts which correspond to limited (414 m.y.) metall- ogenic epochs. The most important metallogenic belts, all of Cenozoic age, are inferred to have been generated during relatively shallow subduction of oceanic lithosphere beneath con- vergent margins. Geological and isotopic evid- ence suggests that magmatic rocks and associated Cu and Au mineralization were derived from asthenospheric mantle sources, which were enriched in a variety of elements (metals, alkalis, S) by dehydration of subducting oceanic crust. Where exceptionally rapid, low-angle 3ubduction took place beneath very thick (>50 km) continental crust, as in the central Andean Altiplano in the Miocene and southwestern North America during the Laramide, ore-related magmas underwent wholesale crustal contamination. However, the associated Cu-Au mineralization is the same as that developed in primitive island- arc crust. In particular, the by-product Au and So contents of porphyry Cu deposits are inde- pendent of crustal thickness and the degree of crustal contamination as determined isotopic- Ally.

Jan 1, 1987

Open pit mines in the Yilgam Craton have unique hydrogeological characteristics resulting from a combination of geology, mineralisation and the complex and extended development of the regolith. The principal features of this geological relationship are:ò deep and complex multi-stage development of the weathering profile; ò steeply dipping rock layering;ò supergene enrichment; andò mining across the regolith/rock interface.These features result in large changes in permeability horizontally across rock layers; vertically through the weathering profile and along-strike in association with mineralisation and the mineralised Structure.

Jan 1, 1993

Thank you chairman, good afternoon ladies and gentlemen. In my talk this afternoon I intend to cover a brief history, some of the recent experiences and an overview of the McArthur River project.If we consider the themes of this forum, Obstacles and Opportunities, I can confidently say that in attempting to develop the McArthur River deposit Mount Isa Mines Limited (MIM) must have encountered almost every obstacle that can be imagined. However the large size and the high grade of the deposit has ensured an opportunity, from which it is very difficult to walk away from.The McArthur River Here's Your Chance (HYC) Deposit is located in the Northern Territory of Australia. It was discovered by Mount Isa Mines Limited geologists in 1955 and is one of the largest known sedimentary stratiform zinc-lead-silver deposits. The deposit has been the subject of numerous investigations and considerable expenditure culminating in a major feasibility study in 1979. There were a number of factors which prevented development, these being the size of the project, the fine grained mineralization, geographical location, market, social and capital cost. The latter had been estimated in the 1979 study to be $800 million at that time.

Jan 1, 1993

The economic significance of a fundamental understanding of the mineral pyrrhotite is dis- cussed. Particular emphasis is placed on the relationship of other sulphide minerals to the pyrrhotite when it is the major sulphide mineral present in an ore body. Studies of the Kambalda nickel deposit are used to give a better under- standing of (a) the genesis and other character- istics of a particular ore body (b) the textural relationships between pyrrhotite and other sul- phide minerals (c) magnetic properties of natural pyrrhotite, and (e) the oxidation and supergene processes that take place in a sulphide ore body.

Jan 1, 1972

By M D. Goodz, Wright R. F

This paper highlights the importance of accurate observational technical reports compiled by Mining Geologists and Engineers. Before uncovering the original reports in July 1992, all previous investigations discounted returning to old mining areas on the belief that all operations were suspended because they were 'unpayable'. However, the detail of the original reports removed any doubt of the economic value of retrieving remnant ore.The important feature was that the description of 'unpayable' by GMA could be equated to 11.6 - 35 g/t over the history of the mine. On the basis of these reports the Morning Star mine has been re-opened.

Jan 1, 1993

By Barlow S

The Kelian Gold mine project won two excellence awards from the Victorian Division of the Institution of Engineers, Australia. It was a challenging project, fast tracked in a remote and inhospitable tropical environment. The creation of a profitable and efficient mine was a significant engineering and project management achievement. The difficulties encountered and the way they were managed provide valuable lessons. These include the importance of sufficiently detailed engineering in all aspects of the job to enable the best estimates possible to be prepared during feasibility studies, the need to prepare the project scope and execution plan with disciplined and rigorous attention to detail by a highly experienced team and the value of identifying, assessing and mitigating risk and uncertainty during execution. The practical benefits of applying these lessons were demonstrated in the successful management of technical uncertainty on the recent diversion of the Kelian River to allow the expansion of the Kelian mine.

Jan 1, 1997

On-line radioisotope gauges determine information on the characteristics of ore to enable improved control of processing operations. In the metalliferous mineral industry, in-stream analysis systems based on radioisotope X-ray techniques determine concentrations of valuable minerals at various stages of the concentration process. In the coal industry, on-line gauges determine ash and moisture contents, and the specific energy of coal.In-stream analysis systems developed in Australia are installed in about 30 mineral concentrators. Their use has led to the increased recovery of valuable minerals, and the time taken to recover the cost of installation is usually several months. The savings to Australia resulting from use of these analysis systems is estimated to be more than $A 15 million per year.Australian experience in the training of mineral industry personnel shows that the most effective approach is to combine courses on nuclear techniques and control of processing operations. This is the basis of Australia's contribution to the minerals sub-project of the United Nations Development Program (UNDP) Industrial Project.

Jan 1, 1985