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By Wright R, Stock E. C

The Windarra nickel deposits known to date comprise two sulphide orebodies located at Mount Windarra and South Windarra. These orebodies, which are 15 km apart, lie within an ultramafic complex at or near its footwall contact with a banded iron formation. The Windarra deposits are 270 km north-northeast of Kalgoorlie in West- ern Australia which was the centre of a major nickel exploration programme fol- lowing the discovery of nickel deposits at Kambalda in 1966. Surface indications of the Mount Windarra orebody were discovered in 1969 by Mr. Ken Shirley while prospect- ing the Laverton area for Poseidon Ltd. (then NL). The mineralisation was loc- ated by systematic prospecting for goss- anous material associated with aero-mag- netic anomalies and ultramafic rocks. The South Windarra deposit was dis- covered in 1971 by the Union-Hanna- Homestake Joint Venture, by exploring along the strike extension of the mount Windarra ultramafic-banded iron format- ion contact. A detailed ground magnet 1. Acting Operations Superintendent, Windarra Nickel Project, Windarra, W.A. 2. Senior Geologist, Windarra Nickel Project, Windarra, W.A. 3. Mine Geologist, Windarra Nickel Project, Windarra, W.A.

Jan 1, 1973

This paper discusses the use of tapered roller bearings in conveyor idlers. It shows that in medium and high capacity systems, tapered roller bearings can offer significant cost and performance advantages. In the next ten years, conventional conveyors will face increased competition from unconventional belt conveyors, pneumatic systems, pipeline "slurry" systems, unit trains and so on. The conveyor industry must meet these challenges by innova- tive use of technology. Conventional belt conveyors must continue to show the lowest cost per tonne-km or lose their position in the market. Tapered roller bearings can contribute to the achievement of this goal. The concurrent resources boom and liquid fuel crises may well see a decline in the use of heavy trucks for bulk material handling over moderate distances 10 to 50 km. There appears to be a trend in the conveyor industry to go to higher speeds with improved belting in conven- tional widths. The transmission of more material over a given period of time will place more demands on conveyor idler bearings. Australia has in general followed the European practice of using deep groove ball bearings in conveyor idlers.

Jan 1, 1978

By Rosengren KJ

Geotechnical conditions often have a critical influence on the design of new open pit and underground mines, but they are often considered of secondary importance in relation to other factors, such as detailed geology, orebody geometry and grade distribution. As a result, geotechnical studies may not be carried out during early project investigations or, at best, may be given only superficial attention, often to the overall detriment of the project. Technically and economically, it is logical that geotechnical studies should be integrated with geological investigations as soon as it becomes evident that the particular deposit may prove to be economic. The paper discusses the use of geotechnical information in the selection of mining methods and mine design for underground mines and for wall design and assessment of excavation characteristics in open pit mines. It then considers methods of obtaining the relevant data, with particular reference to exploration boreholes. Selected case studies on the application of geotechnical data to mine design are Included.

Jan 1, 1986

By Irving R. C

THE objective of the iron smelter is naturally the production of high quality iron at the lowest practicable cost. To enable this, large tonnages are put through the blast furnace, and, at the same time, the quality of the iron must be under definite control.The modern blast furnace enables these objectives to be attained. The description whieh follows sets out the general details of construction of such furnaces, and the operation at thc Broken Hill Proprietary Company's blast furnaces at Newcastle, New South Wales.The occurence of iron in many forms is so well known as to need no description. Modern civilisation may be said to be built on a foundation of iron, and, today, the production of iron and steel has beeome one of the world's industries.A short historical introduction will serve to show the evolution of the processes and apparatus since iron production assumed importance.There is no definite date fixed as to when iron was first made, or by what means it was first discovered. Perhaps prehistoric man threw iron bearing stone on to his fire, and these became reduced, Ieaving a soft metal behind, or more probably the first iron was of meteoric origin.There is evidence, however, to prove that it has been known for a period of 6000 years. Iron has been found in the Pyramids and its use was known to the early Eqyptians and later to the Hebrews, Assyrians, Greeks and Chinese. Following the Greeks, the Romans excelled in its extraction and uses in the manufacture of their instruments of war, and to this fact can largely be attributed the success of their many wars of conquest. As the Romans overran the rest of the then known world they carried the art with...

Jan 1, 1930

By Case JE

Complete Bouguer and isostatic anomaly maps compiled for Costa Rica provide new insights into the crustal structure and mineralization. Terrain corrections were approximated from the station to a radial distance of 167 km by computer using a 3- minute digital elevation model of Costa Rica and surrounding areas. Isostatic corrections, based on Airy-Heiskanen compensation, were also calculated from 0 to 167 km using the 3- minute elevation model and from 167 km to 180 degrees using combined topographic and isostatic reduction maps. Costa Rica can be divided into four main terranes based on gravity data: a Pacific coastal region, a Pacific inland area, a central region, and a Caribbean coastal region. Negative gravity anomalies along the Pacific coastal margin correlate with an offshore sedimentary basin, and large positive anomalies correlate with mafic and ultramafic igneous rocks on the Santa Elena, Nicoya, and Osa Peninsulas, and at Puerto Quepos. Pacific inland anomalies are separated from the Pacific coastal region by a steep gravity gradient, and over the Coast Ranges a major gravity low overlies a thick section of low- density sedimentary rocks. In the central region, a major gravity low occurs over a thick low-density Quaternary volcanic complex in the Cordillera Central, north of San Jose. A prominent feature of the Caribbean coastal region is an interrupted gravity low over the Limon Basin that reflects a thickening of low-density sedimentary rocks. A conspicuous gravity lineament, trending northeast separates northern and southern Costa Rica. The lineament is defined by the termination of several major gravity anomalies including those over the Coast Ranges, Cordillera Central, Puerto Quepos, and Limon Basin. In addition, the lineament correlates with other geological and geophysical data including: northeast-trending faults, the southern limit of large Quaternary volcanoes, the segmentation of the middle America volcanic belt, and a seismicity gap. This lineament may be the expression of a previously unrecognized major northeast- trending fracture zone in central Costa Rica. An important economic implication of the gravity lineament is a correlation with the termination of gold and porphyry copper deposits in Costa Rica.

Jan 1, 1987

By Hodkinson I, Teale GS

Mount Leyshon is an open cut-heap leaching operation that commenced production in early 1987. Open pit reserves are 6.3 m.t. grading 1.8 g/t Au and 4.8 g/t Ag and expected annual production is 68,000 oz. of gold. Gold mineralisation is hosted in breccias, porphyry plugs and basement rocks interpreted as the roots of a multi-phase Permian phreatomagmatic breccia complex. Mineralisation has the form of veins, cavity fillings and disseminations and is localised by late stage trachytic dikes and sills and dike-like bodies of milled breccia in the northwest corner of the complex. The sequence of mineralisation includes: I quartz-chalcopyrite-molybdenite stockwork veins and pyrite-gold veins with potassic alteration II quartz-chlorite-carbonate-basemetal sulphide-gold veins and cavity fillings with sericitic alteration III quartz-basemetal sulphide-bismuth-sulphide -electrum veins, veinlets and dissemin- ations with sericitic alteration. Mineralisation is interpreted to have formed at 500-300¦C from a predominantly magmatic hydrothermal system related to the porphyry intrusive bodies. Mount Leyshon is a phreatomagmatic breccia with a very different origin to the Kidston magmatic hydrothermal breccia. However the mineralisation style and origin is quite similar.

Jan 1, 1987

By Watt JS

The ash content of coal can be determined using radioisotope X-ray techniques. A number of overseas applications of X-ray techniques are described; however these suffer from the disadvantage of either not compensating for iron variations or, if compensation is used, using X-rays of low penetration with consequent sampling difficulties. Current Australian Atomic Energy Commiss- ion (AAEC) research on X-ray techniques is aimed at overcoming the limitations of these methods. The AAEC method involves making measurements proportional to mass absorption coefficients of X-rays in coal at two energies. Calculations and experiments with X-rays up to 35 keV have shown that ash content can be determined to about 1 wt.%. This work is being extended to higher X-ray energies to enable the technique to be used directly on a conveyor belt or in a hopper. Neutron techniques can be used to measure the concentration of specific elements such as carbon, hydrogen and silicon in coal. Their con- centration is correlated to the coal parameters of interest. Methods of moisture determination based on hydrogen measurement and ash determina- tion based on silicon and aluminium measurement are described. Energy content can be determined accurate- ly by analysing the carbon content of coal

Jan 1, 1978

By Cocker A

Pre-splitting for smooth highwall formation is conducted in around 75 per cent of surface coal operations within Australia. The CMTE (Centre for Mining Technology and Equipment) in conjunction with BHPAC (BHP Australia Coal) initiated a project to look at pre-splitting and to investigate the notching of blastholes for fracture plane control. The notching was specifically for pre-split initiation and also for discing of the toe of the production holes to minimise coal loss from the top of the coal seam. There are currently a number of factors which are driving the introduction of new pre-splitting technologies and products. The first is the ever increasing bench height being employed in strip mines which require a higher quality wall with less blast damage to maintain stability. Currently depths of 55 metres are common place with depths of 70 - 80 metres fast approaching. The second factor is the introduction of new technologies or methods which require a high quality highwall produced, eg highwall mining. This paper discusses the current state-of-the-art in pre-splitting and the main issues facing successful pre-splitting in the future. The use of a blasthole notching technology to promote fracturing along the pre-split line is also analysed. The review indicates that most pre-splitting challenges in the future can be addressed through better use and developments of current drill and blast technology. It is also concluded that a blasthole notching technique may find niche applications in improving final walls within a surface coal mine, especially where a high quality wall is required. The notched blasthole method may also allow pre-splitting in ground conditions and adverse rock structure which currently cannot be pre-split by existing technology.

Jan 1, 1995

By T Baumgartl, B Richards

Covers on waste rock and tailings remain the primary choice for closure planning where the purpose is to create an environment where water ingress into reactive material can be controlled and/or prevented. In semi-arid and arid environments, dry cover systems are the preferred option with the design intention to absorb rainfall and to prevent deep drainage. Although the average amount of rain typical for semi-arid environments is relatively low and evaporative demand is high, the seasonal and annual distribution may vary greatly. Rocky substrates are often the only choice for the construction of covers due to economic constraints or availability of suitable materials. While the water holding capacity may be suitable for the application of a dry cover design in arid and semi-arid climates, some of these covers bear the risk of preferential water flow when rain events are intensive or occurring at high frequency. The objective of this presentation is to demonstrate the occurrence of preferential flow through rock containing dry cover systems. A regional classification for the applicability of dry covers is attempted to delineate those regions of Australia where the characteristic of the rainfall pattern increases the risk of failure for dry cover designs. CITATION:Baumgartl, T and Richards, B, 2016. Rainfall patterns rather than climate classification control cover design for closure, in Proceedings Life-of-Mine 2016 Conference, pp 89–92 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By Drew GJ

Smelting is a process in which heat is applied to ores to produce metals. Impurities are removed by segregation in the slag, or converted to gases or sublimates and discharged up the flues. Mate- rials delivered into the smelter have generally been previously concentrated or processed at the mine, and the size of their particles, and also their chem- ical composition, greatly affect the smelting proc- ess. Some impurities are more difficult to remove than others, and are more objectionable in the finished product. The first metal mine in Australia was opened near Glen Osmond in South Australia in 1841, for silver-lead ore. It was followed by the Kapunda Mine for copper in 1844 and by the very signifi- cant Burra Mine, also for copper, in 1845 (Figure 1). A major part of their ores could not be exported profitably for smelting in England and Wales where the large smelters were then located. In addition to treating ores from Cornwall these also smelted ores from recently opened mines in Cuba, Chile, and Mexico. The Welsh smelting process (Figure 2) was developed over a period of years to utilise Welsh coal to treat copper ores particularly from Corn- wall. The first step consisted of a calcination to remove sufficient sulphur from sulphide ores so that subsequent melting operations would produce copper matte, a copper-iron-sulphide which melted at about 1050¦C. Subsequently refined to white metal with the addition of carbonate and oxide ores when these were available, and often through an intermediate step of blue metal, this matte was finally oxidised to pure copper, or as pure as it could be made in those days. The movement of metal towards greater purity was matched by a reverse flow of slag, carrying reducing quantities of copper, so that the slag rejected from the first melting process carried the minimum quantity of copper. Chemical analysis was virtually unknown. Materials were assayed in the laboratory by a small scale smelting process, and the purity of the final refined copper was judged b} the ease with Mhich it could be hammered into thin sheets.

Jan 1, 1987

By A E. C Peres, P R. M Viana

The role of flotation columns in comparison with conventional mechanical flotation cells is discussed under the scenario of Brazilian flotation technology. All iron ore concentrator circuits commissioned since 1990 incorporated column only flotation technology in rougher, cleaner, scavenger configuration. Columns were also added to existing circuits, especially at the cleaner stage. Columns were also incorporated to phosphate ore flotation circuits operating mechanical cells. In two phosphate concentrators, columns substituted for all mechanical cells. Columns perform the cleaning stage in a large sulfide copper concentrator, following rougher flotation in tank cells. Scavenger of the cleaner tailings is performed in tank cells at this plant. Other ores that are concentrated in flotation columns include graphite, talc, lead-zinc sulfide, and a zinc hydrometallurgical residue for silver recovery.

Jan 1, 2005

The theory of declining optimimum cut-off grades is more than 25 years old, but for a number of reasons it is still not widely used in industry. A lack of faith in the veracity of estimated grades is not in itself a reason to abandon any attempt to optimise cut-off grades. The use of declining cut-off grades has been thought to cause high-grading, but in fact this is only true if an artificially high discount rate is used in the calculations. Perfect application of an optimum cut-off grade should ensure that only ore generating more than a minimum net return is mined, and that as much as possible of the ore capable of generating that return is mined. Therefore differing mining costs in different parts of some underground mines necessitate local modifications to cut-off grade. Optimisation of cut-off grade is of necessity an iterative process. Integration of that process into a feasibility study need not be excessively time-consuming. A number of approximations can be made to speed the optimisation (any attempt to achieve a high level of accuracy is probably doomed to failure by a lack of precise cost and price projections). A procedure is outlined for optimising cut-off grade during planning of a typical underground mine.

Jan 1, 1991

The use of teleoperation in mining is increasing due to requirements to improve safety and reduce the number of people required to work in remote and difficult environments. We recently completed a project to develop a teleoperated control system for a rock breaker at an iron ore mine in the Pilbara region of Western Australia, with the objective of demonstrating the feasibility of remote rock breaking over long distances. This required controlling both the rock breaker and an array of pan-tilt-zoom (PTZ) cameras using joysticks. Controlling the cameras distracted operators from the primary task of controlling the rock breaker to position and fire the hammer. This lengthened task times as both the operator's attention and their hands have to swap between different control interfaces. In this paper, we present a novel design using human eye gaze as an interactive input for the remote camera control. It follows a simple and natural design principle: Whatever you look at the screen, it goes to the centre. A prototype system has been implemented by integrating computer vision based eye tracking technology, with the advantage of being real-time, robust and marker-less. We conducted a user evaluation, where users undertook a control task while obscuring the direct view of the working area and using a remote camera to transfer the live video stream as the visual feedback. Subjects were required to participate in the experiment using eye tracking camera control and traditional joystick control respectively. The statistical analysis of objective measures indicated that our novel eye tracking control significantly outperformed the joystick control. The results of the post-experimental subjective measures also revealed much higher user preference for using eye tracking control, which provides clear evidence that this design is a better interface for remote camera control in mining teleoperation settings.

May 1, 2010

By OÆBrien D. R

Up until June 1988, Mount Thorley Coal Handling and Preparation Plant disposed of tailings by two methods. Approximately half of the plant tailings was mechanically dewatered by solid bowl centrifuges mixed with plant reject and was subsequently disposed in mine overburden spoils; the remainder was pumped to tailings ponds. Both future mine planning and environmental constraints could not allow for the long term construction of more tailings ponds so, following evaluation of available dewatering technology, belt press filters were selected for the treatment of tailings in excess of the capacity of the existing solid bowl centrifuges. Commission of the four 2.5 metre wide belt press filters soon showed that marked differences in performance were experienced when treating different coal seams. Further analysis showed that the coal tailings from different seams were quite different in terms of clay mineralogy, and these differences could be correlated with varying degrees of filter performance. Poor filter performance was experienced with coal tailings rich in sodium montmorillinite clays. A number of variables were investigated including in-line mechanical mixing of flocculant and feed slurry, cation exchange reagents such as gypsum, and upstream addition of cationic flocculant. In order to achieve satisfactory performance on the worst tailings, a combination of all of the above was required. In this paper, the reasons for selection of belt press filters and the program of investigations and testwork required to arrive at satisfactory belt press filter performance for the treatment of troublesome bentonitic rich tailings are discussed.

Jan 1, 1989

By Van Heuzen JA

The extensive deposits of brown coal in the Latrobe Valley form the major solid fuel resource in Victoria and are the energy source for most of the State's power generation. This paper describes the coalfield resources allocated for electricity generation and a potential sequential develop- ment of these areas in future years to supply future power stations.

Jan 1, 1982

The South American mining community leads the world in recognition and adoption of the latest grinding mill relining technologies. Clearly this region has recognised the benefits of improved relining performance as a defence against the Global Economic Crisis. Five of the six RUSSELL TWIN 8 Mill Relining Systems, ordered to date, are either operating or being manufactured for South American mine sites. The sixth is for Sino IronÆs Cape Preston Project in Western Australia. This paradigm shift, towards very short relining times, aims at displacing mill relining activities from the critical path of concentrator maintenance shutdown schedules. The first uses of the RUSSELL TWIN 8 Mill Relining System have seen some of the highest semi-autogenous grinding (SAG) mill new liner placement rates ever observed by Russell Mineral Equipment (RME), as would be expected with two, independent Machines working simultaneously in the one mill. The liner replacement rate, averaged over the whole reline is good (27 per cent improvement over single Machine System in the same mill) but short of full potential. This modest result can be attributed to reline crews unfamiliarity with RUSSELL TWIN 8 System operation. This paper compares a sample of conventional (single machine) RME Mill Relining System performance data with one ædouble headÆ mill liner handler by others. Early performance of EscondidaÆs new RUSSELL TWIN 8 System performance is then compared with recent single machine data from Escondida, immediately prior to RUSSELL TWIN 8 commissioning. RME and Escondida look to constantly improving RUSSELL TWIN 8 System performance as full operational familiarity is achieved. The preparation of this paper revealed a need to develop a global industry standard for mill relining data collection. A web based platform to develop data collection templates is also discussed in Appendix 1.

Jan 1, 2009

Quite often the reserve assessor becomes enamored with the numbers gen- erated and forgets the basis for his assessment. The quality of the assess- ment can only be as good as the quality of the input data. The use of seismic data from the Gippsland Basin in assess- ing Esso/BHP's oil and gas reserves is an excellent example of this principle. By significantly improving the quality of seismic data, a much more reliable estimate of a field's reserve potential can be made. In addition, it provides the basis for further delineation drill- ing which, as recent experience in Gippsland has shown, often leads to increased reserves.

Jan 1, 1979

By Rosmus P

Improper use of auxiliary ven- tilation units during heading operations may often result in the appearance of hazardous methane accumulations. This is the case especially when roadways are ventilated by a combined system with a short sucking pipe at face end performing as the dedusting installation. Uniform air inflow to the face end facilitates sucking off the dust clouds and creates conditions favourable for formation of local methane accumulations. The highest methane concentration occurs in the cutting zone between the rock cut and the pipe inlet, under the roof and by, the sidewalls. Permanent monitoring of methane concentration at face end employs methane sensors. The most important are: one on the road- header's boom behind the cutting head, and one at the air outlet from the dedusting installation.

Jan 1, 1988

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 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