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The excavation of sandstone of generally medium strength for the Liverpool Link Line by Dosco Mark 2A Roadheaders has demonstrated the versatility and good performance of road- headers in suitable rock formations. A description is given of the strata traversed by the tunnels together with descriptions of equipment and crews, excavation sequences, operating difficulties and the results achiev- ed. In addition tunnel construction is des- cribed for a difficult section where there was only O.Sm clearance between invert and a four lane vehicular tunnel below, and O.5m clearance between tunnel crown and a century old sewer above.

Jan 1, 1976

By Lloyd C. J

The uranium markets are at present well covered by available producers. However the predicted increase in demand, recently reinforc- ed by the Arab oil crisis, will by, the early 1980s'outdistance supply. Current trends are towards light water reactors with-fast breeder reactors not expected to make any significant impact to the mid 1980s. The proposed lifting of the US embargo on the use of foreign uranium in US reactors will expand the market available to non US producers. A balancing in supply and demand worldwide will probably occur in the early 1980s. Australia's potential producers at present hold about 20 percent of the worlds U308 resources. Three companies, have contracts to supply nearly 10 900 tonnes of U308 between now and 1986 which represents about 1 percent of the predicted demand to 1986. Australian producers need to establish themselves more firmly in the market place in order that other countries will not replace us. Contracts can be written now which will allow for world market prices to be paid in the future, thus protecting the Australian producer.

Jan 1, 1974

The Fosterville goldfield, situated 25 km east of Bendigo, Victoria was at its peak between 1894-1910 with some 47 600 ounces produced (Figure 1). Since that time intermittent mining and tailings retreatment was undertaken until Bendigo Gold Associates delineated a viable resource and commenced an open cut heap leaching operation in early 1991. Unfortunately they encountered financial difficulties and Perseverance Exploration purchased the mine in April 1992. Perseverance operated a successful heap leach operation nearby Nagambie, 100 km east of Fosterville. Based on its acquired heap leaching experience, Perseverance Exploration was able to instigate operational changes to create a successful small gold heap leach operation. The major change was the using of the original multi-use leach pad as a single-use leach pad. The available data allows for a comparison of the two operating systems.

Jan 1, 1994

By Mack JF

A metallurgical evaluation of the Argyle Kimberlite No. 1 (AKl) orebody has been carried out using a 40 tonnes per hour pilot plant. Pilot plant results, together with laboratory investigations provided a basis for the determination of process design criteria for a major treatment plant. Various sampling programmes were carried out to determine specific aspects in the evaluation of diamond liberation. Treatment parameters such as the top crush size, recrush size and the bottom cut-off size were investigated. A description of the pilot plant is given together with the design criteria for a 3 million tonne per annum treatment plant

Jan 1, 1984

By Jones IO

Although small units have been in use formany years, particularly in opal mining at shallow depths, there has been little effort in the past to explore the potential of the vacuum lift system in other more demanding applications. Recent developments in Western Australia by a small number of mining companies, contractors and manufacturers have seen the design and construction of several larger, more powerful units for use in winzing, shaft sinking, hoisting and spillage removal. Some of these units have proved very successful and suggest that they could be developed for a wider range of applications and duties in future.

Jan 1, 1984

By Laing W. P

Sedimentary structures are described from the WiIlyama Complex, New South Wales. Their presence confirms lithological layering within the metasediments as bedding. These primary structures occur not only in low grade rocks as previously reported by other workers, but also in areas of medium and high grade metamorphism.Sedimentary structures include graded beds, cross beds, ripple marks, and ball and pillow structures.The observed parallelism of the early schistosity and bedding in the Broken Hill area has previously led to the idea of transposition by isoclinal folding.In the areas mapped, small scale transposition is precluded on the basis of1. uniform facing of sedimentary structures over wide areas, and2. the existence of large areas in which the early schistosity is oblique to bedding.

Jan 1, 1975

By Poole GR

An unusually high flow of water from an oxtr.iction panel in Wongawilli Colliery pr,;npted the investigation of the possible sources of the water. It is more probable that water is derived f r,m sources adjacent to or within the Woo ' iwi 1 I i Coal rat her than by direct t r.onnuni n i"n from any surface source.

Jan 1, 1986

From the viewpoint of mechanical efficiency, charges should be fully coupled and, upon detonation, should just fail to break the rock in compression. But because mining thrives on its cost-effectiveness rather than its mechan- ical efficiency, the explosive which generates maximum energy per $ should generally be used, even though the mechanical efficiency of this explosive's detonation products may be sub- optimum. Wherever possible, each charge should have a length:diameter ratio of about 20 or more and should shoot to a concavely biplanar free face that is both parallel and reasonably close to the blasthole. Success in obtaining parallel effective faces often demands the drilling of angled blastholes and, hence, will require intensified research and development efforts by drilling manufacturers, especially where hard strong rocks are encountered. Blastholes should be drilled on equilateral triangular grids and fired in a Vl or shallower V-type sequence using inter-row delays which ensure that good pro- gressive relief of burden is achieved. The conventional method of calculating Se/Be values (on the basis of planar effective faces) is often invalid.

Jan 1, 1986

By Thompson IR, Solomons SS

Underground mining with the cut and fill method has been declining during the past decade or so, being replaced mostly by sublevel open stoping methods. During 1983 the Australian Mineral Industries Research Association Ltd. (AMIRA) commissioned a review of the method, with the aim of compiling the state-of-the-art, indicating future trends and recommending topics for research that would be needed to support this future mining. Mines using the cut and fill method in Australia and three other countries were visited to compile current practices and expected developments.Cut and fill is mostly used where geological and ground conditions are unsuitable for open or caving methods. These range from narrow, irregular orebodies to wide, massive orebodies where pillars are retained in ore. There is significant potential for improvement and further development of the method. It may then be used in a broader range of conditions and for orebodies that may not otherwise be viable to mine.

Jan 1, 1985

Although developed primarily for sintering tantalum, the unit to be described can be used to heat-treat metals in the form ofa bar, wire or strip, by passing a current through them. The upper temperature limit with this type of heating is the melting point of the metal being heated.The unit was designed for vacuum work, but. various gases can be used if required.Briefly, the vacuum sintering furnace consists of a bell which is counter-balanced and may be lowered onto the brass base plate which holds the electrodes. A rubber ring seal is used for vacuum work. The lower flexible grips are bolted to the brass base plate which is at earth 'potential, while the other electrode passes through the plate by way of an electrically insulated vacuum seal. This upper electrode, the height of which can be altered as desired, the lower grips, and the bell are water cooled. The vacuum line to the pumps and a line to the vacuum gauges also lead from the base plate. The more important sections of the unit are described below.THE BELLThe unit was designed so that the bell could be lifted clear of the base plate and the electrodes, thus facilitating adjustment of the latter and the mounting of the specimen to be heated. A double walled steel bell, 20 in. high, with t in. cavity was used. The bell was fabricated from 10 gauge mild steel sheet using a double overlapping run of arc welding for all seams. A water inlet and outlet...

Jan 1, 1946

By Matthews SM, Gooding JE

N Longhole Open Stope at The Zinc Corporation Mine was developed in an area with large and continuous tension cracks. These cracks resulted fran widespread block subsidence into previously mined areas. The practical problems encountered and their solutions are discussed together with an outline of a new method of stope wall support using large diameter dowels installed sub-parallel to the stope wall.

Jan 1, 1985

By Hinrichsen H. D, Rathburn D. R, Stieger W

The present situation in the field of iron ore pelletizing is briefly described with particular view of the Lurgi/Dravo travelling grate process. To meet todays pellet quality requirements with regard to physical and metal- lurgical properties it is often necessary to add basic fluxing materials. It has been de- monstrated that for certain ores, basic addi- tives provide a considerable improvement in fired pellet quality. The production of self- fluxing pellets is becoming increasingly attractive. One Lurgi/Dravo plant is now in operation and another is under construction which were designed for the production of self- fluxing pellets. Self-fluxing pellets may be considered as the primary or exclusive blast furnace burden and the installation of a sinter plant is not necessary if the pellet plant-can handle all in-plant fines. Reference is made to the first pellet plant utilizing iron ore concentrate, in-plant fines and basic flux. The use of solid fuel for pellet indura- tion is discussed because of the increasing prices and possible shortages of heavy oil and natural gas. Since there is a strong tendency to increasing plant capacities, the design fea- tures of travelling grate pelletizing plants for productions up to 6 million tonnes are Discussed.

Jan 1, 1974

LESLIE BRADFORD GOLDEN JUBILEE ORATION "Not only a metallurgist but a scientist of the highest order" Leslie Bradford and the Australian Metallurgical Industry

Jan 1, 1987

The Century zinc-lead-silver deposit has a geological resource of 118 million tonnes averaging 10.2% zinc, 1.5% lead and 36 g/t silver. It lies approximately 250 km NNW of Mt Isa in NW Queensland, Australia, and is hosted by middle Proterozoic age siltstones and shales of the Lawn Hill Formation. Within the orebody, most mineralisation occurs selectively within black shale units as fine grained sphalerite and galena lamellae with minor pyrite and siderite. The black shale units are separated by weakly mineralised sideritic siltstone horizons. The deposit is unmetamorphosed and only weakly deformed, displaying excellent lateral stratigraphic and grade continuity.

Jan 1, 1995

Drill and blast excavation in underground mining and. civil engineering projects has grad- ually given ground to mechanical boring of tun- nels, shafts and raises during the past twenty years. The use of.boring equipment must today be considered significant and wide spread al- though comprising only a very small percent of total underground excavation. The encroachment of mechanical boring into the domain of blast- ing has been by slow incremental advances. There have been few, if any major breakthroughs in this development, and none can be foreseen in the next decade. After 1990 it is possible that scientific. development will provide some form of breakthrough in rock breaking, but this is so uncertain that it should have little relevance to planners in the 1980's. A more near term view of the future, con- centrating on the next five to ten years, has lead to the conclusion that significant im- provements will be seen in tunnel borers for poor ground conditions. A universal machine will be developed that converts from a dry hard rock machine to a closed slurry type machine for passing through fault zones with unstable crushed rock and water. Two other machines have been described as alternate designs for tunnelling in squeez- ing ground conditions.

Jan 1, 1981

By Hill J. R M, McDonald M. M

A prediction technique for support perfor- mance of hydraulic backfill in narrow stopes is applied to two stopes separated vertically by a sill pillar. Predicted stope wall closures and fill pressures compare favorably with field measurements taken over a period of several years at two mines in the Coeur d'Alene dis- trict. Stope wall closure and peak pillar stress can be substantially reduced by improved fill quality within a practicable range of fill and rock properties.

Jan 1, 1973

By J McQuie

The concentrator at WMCÆs Leinster Nickel Operation has operated with flash flotation in the grinding circuit since the early 1990s. There has always been a positive correlation between flash flotation Ni recovery and overall Ni recovery û however this relationship could be explained by differences in the ore, rather than by the action of the Flash flotation cell in reducing overgrinding of Ni. In July 2003, refurbishment within the plant made it necessary to operate the concentrator for a period with the flash flotation cells off. The resulting data set provided evidence that flash flotation in the grinding circuit changes the size distribution of Ni to reduce the amount of slow-floating fine (-7 ¦m) Ni produced. Ni recoveries in the finer size fractions were similar with flash flotation on or off û but because less fine Ni is produced when the flash flotation cells are operated, overall Ni recovery improved.

Jan 1, 2005

By Edwards A. B

Re-opening of the old Proprietary mine has provided new exposures of the system of uralite dolerite dykes observed in 19110 by the Geological Sub-Committee of the Scientific Society of Broken Hill. The newly exposed dykes have been invaded and replaced by the massive ore, with development of manganese garnet and biotite adjacent to the sulphides. A similarly altered dyke in massive ore has been encountered in the North Broken Hill mine.The textures of the unaltered portions of these dykes indicate that they have not been affected by the intense regional metamorphism that has recrystallized the other rocks of the area. Moreover, in mineral composition and textures, in chemical composition, and in cross-cutting relations, they are so similar to the uralite dolerites of the district which post-date the folding and metamorphism of the Broken Hill area, that they must be regarded as typical members of this suite of post-metamorphic dykes.The invasion and replacement of the dykes by the massive sulphide ore, and their metasomatic alteration adjacent to the invading sulphides, establishes that the lode was formed after the dykes were intruded, so that the high temperature features of the ore cannot be attributed to metamorphism and recrystallization, but are primary features of high temperature hydrothermal deposition.INTRODUCTIONTwo cross dykes are recorded on the plan of the 300-ft. level of the Broken Hill lode accompanying the report on the geology of the Broken Hill lode published by the Geological Sub-Committee of the former Scientific Society of Broken Hill (1910). One dyke occurs in Block 12, and the other in Block 13, and both were stated to consist of a dark basic amphibole rock, called diorite for convenience. The more southerly dyke was traced from some distance out in the footwall, and even through the lode, by means of occasionalpatches of it still existing in the ore, in a direction...

Jan 1, 1956

By Spottiswood DJ, Kelly EG, Bull WR

An empirical model of a 254mm water-only cyclone treating minus 17001im coal has been developed. The model includes the prediction of by-passing, SG50 corrected, water split and the use of a single equation forthe reduced performance curve of particles in the range 1700-106pm. Particles finer than 106pm did not separate according to specific gravity. Simulations using the model showed the water-only cyclone performance to be dependent more upon feed size distribution than washability when the feed contains high-ash fines, but that, with a deslimed feed, the yield and ash content of the over-flow should be controllable by altering feed rate or feed pulp density.

Jan 1, 1985

Dartbrook mine is a new greenfields thermal coal longwall mine located n the Upper Hunter Valley ten kilometres north of Muswellbrook Figure 1). Construction began in April 1993 with coal extraction starting n October 1994. Longwall production is scheduled to commence in the first quarter of 1996 with production expected to exceed 3.5 million onnes per annum. The permanent workforce will number 150 full-time ,mployees and productivity rates will be 22 000 per employee per annum m a ROM basis. Being a greenfield site Dartbrook has had the opportunity to develop and operate the mine using the best practices and latest technology available to meet high standards of safety, quality and production.

Jan 1, 1995