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By Coombes J, Richards W. L

The objective of this paper is to illustrate, in a practical way, how both geologists and mining engineers can use conditional simulation to add value to their decisions. Inherent assumptions, requirements and essential components of condition

Jan 1, 1998

From the ventilation aspect, there is a basic difference between advancing and ezreating longwall layouts. Particular rroblems with retreating, using differing mining methods and layouts include high gas emissions, spontaneous combustion and -radients. There is an acceptable method of crntrolling the environment at the return end a retreating longwall face without the use a multiple heading system. Incorporated in the design is the facility to practice xtensive methane drainage, thus ensuring a ntrol of the rate of methane emission into the main roadways. Case studies highlight varying mining editions under which the proposed system of Ctised.

Jan 1, 1982

By C McIntosh, M van Dam, N Whetter, R Lane, M McCulloch

Mine geology is understood through synthesising large amounts of structural, lithological, geochemical and geophysical data derived from the original topographic surface, drilling and surfaces exposed and removed during open cut and underground excavations. Computer- generated 3D geological models of any mine environment need to incorporate large amounts of information but also should be regularly updated with typically frequent influxes of new data. Geologists with the local knowledge should also be involved in the model construction, enhancement and interpretation, placing ease-of-use functionality high on modelling software requirements. Implicit-style modelling is a fast-growing area of 3D geological software development where interpolated surfaces such as lithology boundaries and bedding orientations are defined mathematically as functions rather than explicitly through coordinate meshes. The functions are constrained only by the data and not by an artificially imposed grid; therefore, implicit 3D modelling can process a lot of information quickly and routinely operate on original data (such as observed contacts and structural data) rather than on evolved iterations and interpretations. 3D mine geology models can be readily updated with new data, which can be automatically reprocessed to test ideas in near-real time. Implicit, function-based 3D modelling software has been applied to the Globe-Progress mine in West Coast, New Zealand. This structurally- hosted gold mine has some geometrical conundrums that are in part being resolved as excavation of the open pit proceeds. The relationship of the Globe-Progress ore shoots to hanging wall and footwall structure is still not fully understood, however, and 3D geological modelling is assisting with visualisation and testing of structural hypotheses. The modelling is also capable of predicting areas of bedding defect slope failure in yet-to-be excavated parts of the mine.

Jan 1, 2009

By Kubo H, Ninomiya R, Ojiro T, Sato T

New high-strength Zn alloys for moulds are demanded from the automobile and electric industries in Japan, because the s rength of Zn moulds is still not high enough for the mass production. There are two approaches to improve the strength of Zn alloys. One is to increase the Al content. ZA alloys (ZA-8, ZA-12, ZA-27) were developed through this approach. The other is to increase the Cu content. But it is known that an increase in Cu generally depresses the castability of Zn alloys, so that the alloys with increased Cu have been rarely studied until now. In this study a reconciliation between the strengthening and the castability of Zn alloys by enriching both with Al and Cu has been attempted. Accordingly we have studied on the Zn alloys containing 4 to 25 mass per cent Al and to 24 mass per cent Cu have been studied. Their fluidity, which primarily corresponds to the castability of the alloy, were measured first and 19 alloys were selected based upon their fluidities and casting temperatures. Mainly the mechanical properties of all 19 alloys were tested and some were found to be excellent in both strength and castability. Z1009 (Zn-IOAI-9Cu-0.02Mg alloy) cast in a sand mould has the tensile strength of 360 MPa while ZAS (Zn-4AI-3Cu-0.04Mg alloy), which is the most popular alloy for moulds, is 215 MPa. Z2520 (Zn-25AI-20Cu-0.02Mg alloy) cast in a sand mould has a Vickers hardness of 178, compared to 107 for ZAS and 104 for ZA-27 (Zn-27AI-2Cu-0.02Mg). Furthermore the castability of Z1009 is as good as that of ZAS. The underside shrinkage occuring in casting ZA-27 is restrained in Z2520.

Jan 1, 1993

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

Knowledge of the hydrogeological setting of a mine forms an integral part of a mining operation. Groundwater impacts, initially, on mine feasibility. Then, on commencement of mining, it interacts on the operational components of dewatering, water supply, tailings leachates, mine wall stability, stormwater run-off, water disposal, impact on regional environment and mine closure planning. The recording of hydrogeological information is frequently overlooked during resource and reserve definition as well as during the course of mining when prime opportunity exists for the collection and collation of this data. In recent times, the exclusion of hydrogeological data has been exacerbated by use of high air pressure drill rigs that exclude water inflow. The recording of water data has been further inhibited by the use of computer coded drill logs that do not include the site geologistÆs or drillerÆs comments on drilling problems and observations associated with groundwater intersections. Geologists now infrequently directly supervise drill rigs, but visit the rig only intermittently to evaluate drilling progress. They do not see first hand drill performance characteristics at water make zones. Drill cuttings, as drill chips and cores, are now mostly logged away from the drill site so that wet sample locations, visual water flow evidence and verbal comments from the driller are not recorded. As a result, mine geologists now do not direct adequate attention to the delineation of lithologies and structures that store and transmit water. This paper provides examples of water sighting and recording techniques applicable to a mining operation. Examples are also provided where hydrogeological conditions have been disregarded with serious impact on the progress of mining. The recording of hydrogeological data should be maintained and formatted by the site geologists into a useful database for review as and when required by specialists in hydrogeology, geotechnical and mining engineering and the environment. The information can be coded by the site geologist for inclusion into the mine database. A groundwater dataset, compiled during the progress of field investigations, will save the considerable cost of re-drilling and hole re-entry testing which would otherwise be required to provide base level hydrogeological information required for progress of mining. Apart from working mine use, a hydrogeological dataset is a necessary component for planning mining closure and mine legacy conditions.

Jan 1, 2003

By L Terrusi

The Bungaroo Valley hosts a concealed Tertiary channel iron deposit (CID) along a 17 km stretch of its length. Bungaroo Valley is approximately 0.5 km wide upstream at its easternmost extent, and 3.5 km wide downstream where it joins the Jimmawarrada Creek. The valley follows the axial trace of an anticline that plunges gently to the southeast, and the CID infills the valley. Mineralisation extends to a depth of 230 m below the surface, and almost the entire deposit occurs below the water table. Bungaroo Valley cuts through the Buckland Hills and is bounded to the north and south by steep scarps capped with the resistant Dales Gorge Member of the Brockman Iron Formation. Basement rocks are believed to be mostly Wittenoom Formation shales and dolomites, with Mount McRae Shale and Mount Sylvia Formation also present. Deep, localised depressions appear at the base of the CID sequence towards the north edge of the upstream section of the valley, while downstream the basal CID contact is relatively flat and shallow. In both cases the profile of the CID surface closely mirrors that of the basal contact. The localised depressions seen in the upstream basal CID contact produce significant variations in CID thickness of up to 100 m over short strike distances. This uneven palaeotopography is most likely due to eddying and waterfalls forming within the riverbed prior to CID deposition during a time when the water table was much lower than at present. It may also be associated with possible karsting in an underlying dolomite unit and subsequent syn- or post-depositional collapse of the overlying CID. The irregular basal contact of the Bungaroo CID sequence has implications for mining in terms of pit design and resource accessibility.

Jan 1, 2007

By Soma T

Pyrite and Cu-concentrate were roasted in vertically suspended state in an externally heated tube. Tubes of three different lengths of reaction zone were used for three different reaction times. Roasted ores were submitted to chemical analysis and the extent of roasting reactions was determined. In case of pyrite, extent of roasting reactions was not affected much by reactor length and heating temperature (above 500¦C), but was considerably by ore/air ratio. Micro- scopic and XMA examinations led to the conclus- ion that pyrite particles decomposed to pyrrho- tite and then pyrrhotite was oxidized to give Fe-S-0 melt, magnetite and hematite. The extent of reaction was not uniform in all particles but had a wide distribution from unreacted pyrite to completely oxidized particles. Combustion of Cu-concentrate from Kuroko complex sulfide ore ) was unstable under a uniform wall temperature of 450¦C, but proceed- ed rapidly at temperatures above 500¦C. Sticking of roasted ores to the wall of the reaction tube induced choking of the tube, caused by melting of roasted ores, at tempera- tures above 950¦C. Enrichment of oxygen exterted less influence on reaction rate than heating temperature of the tube. Particle size of ore had a big effect on reaction rate.

Jan 1, 1980

The difficulty in creating and obtaining a competitive edge in the mineral industry is rapidly increasing. The Kiruna Iron Ore Mine in the far north of Sweden is currently thriving on the world market through firm managerial strategy. LKAB believes in upgrading its raw material to produce a high quality iron ore product for sale to steelworks throughout the world. It is vital that this product is also of uniform quality and quantity to provide quality assurance to customers. The first link in meeting these product requirements starts in the underground workings. Mining methods and operations are of large-scale. Automation and continuous production streamline operations and reduce operating costs. These factors have built Kiruna Iron Ore Mine into the world's biggest, most modern, underground iron ore mine. To remain competitive on the world market, LKAB relies heavily on research and development. The mine is currently in a phase of upgrading its operations. A 25-tonne Toro electric loader is being tested to improve the rate of output of ore from the mine. Long hole drills are being improved to increase accuracy and efficiency. An electronic detonating system will improve detonator delay precision. Projects are underway to better understand ore flow mechanisms from a caving orebody. Benefits include improved ore recovery along with better rock quality control at the caving front. The continued updating of mining operations at Kiruna will enable LKAB to continue to maintain its competitive advantage on the world market in the production of high quality iron ore products.

Jan 1, 1997

By C Fountain

Australian mining and engineering companies have increasingly been investing in the mining industry in Brazil. It is a country of enormous mineral and agricultural wealth, with a well-established mining sector. Some Brazilian mining companies and personnel have been journeying in the opposite direction. There are significant differences in the approaches to engineering between the Australian and Brazilian industries that can cause confusion for companies operating in the other country. These range from differing expectations during the various stages of feasibility studies to style of plant and contracting strategies during the construction phase of projects. Some of the differences are driven by tax regimes, labour costs, or different settlement patterns. Others are the result of different histories and pressures on the industries in the two nations.This paper describes some of the differences in approach found in the two countries and some of the reasons for them.

Aug 8, 2011

By Carthew J

For more than 30 years shearer loaders have been the most important winning machines for,longwall mining. While the machines of the first generation had a driving power of only 100 or so kW, the present day shearer loaders may be powered by more than 1000 kW. Daily outputs of 24000 tonnes have now been reached, but this still does not set a limit. If the deposit conditions allow, further increases are possible. This requires the optimum coordination of all system components. For this paper the use of coal plows has been of little import as plows have found no favour, and nor are they likely to do so in today's economics in Australian coal mining.

Jan 1, 1988

By D Moy, T Carter

This paper outlines the feasibility assessment conducted to explore the possibility of constructing two submarine water supply pipelines beneath the Ma Wan Channel in Hong Kong using either horizontal directional drilling or tunnelling. The Ma Wan Channel is a major shipping channel in the Northwest New Territories, which separates Ma Wan Island from the mainland. The challenges faced by the projectÆs designers included space limitations on either side of the channel, marine department restrictions on construction activity within the channel and selection of a suitable crossing alignment and profile given the channelÆs depth, irregular sea floor topography and complex geology. The existing geological information indicated the proposed alignment would cross granitic and volcanic formations, which would likely be faulted. The primary concerns with horizontal directional drilling were:the length, diameter and depth of the crossing were at the limit of precedent experience in rock; the lack of available space at both the entry and exit sites; and whether the technique would be flexible enough to cope with the anticipated range of ground conditions. The primary concerns for tunnelling were: the possibility of encountering large inflows of high pressure groundwater; andthe possibility of encountering disturbed ground within the fault zones which could flow if not properly treated. As a means to evaluate and mitigate these technical risks for both construction options, a directionally drilled pilot hole was used to investigate the ground conditions along the proposed pipeline alignment. The pilot hole results indicated that either directional drilling or a closed face TBM drive were technically feasible crossing options at a crossing depth of 80 m. The results also indicated that either an open face TBM or a drill blast drive would need to be constructed at much greater depth because of the presence of highly permeable, disturbed ground in mid-channel at this crossing elevation.

Jan 1, 1999

By J J. Campbell, G J. Wilkie

The ores of the Golden Mile exhibit considerable complexity. As a consequence, the operating company, Kalgoorlie Consolidated Gold Mines (KCGM), considered it important to develop a coherent database of information describing the nature of the many ore lodes in terms of (1) rock properties and mineralogical content, including relative proportions, grain size, associations and deportment of key elements between minerals, (2) the relative behaviour of consituent minerals in various stages of processing and (3) the nature of the final products and key intermediate streams. The paper describes a sequence of metallurgical tests covering comminution, flotation, gravity concentration, leaching and calcining, carried out on three lodes of the Golden Mile. Key samples generated by the testing were subjected to comprehensive size-by-elemental assaying and QEM*SEM mineralogical determinations of sulphide and precious metal associations. Significant differences between lodes were identified, and the impact of these differences on processing is discussed.

Jan 1, 1998

This paper examines the impact of the time value of money on the location of mining facilities, as examplified by a central processing plant serving several mines. Three approaches, the Euclidean-Distance Approach, the Gravity Centre Approach, and the Rectilinear-Distance Approach, commonly applied to a single facility location problem were employed in the study. The objective function in all three models was the updated value of the following three costs influenced by the processing plant location and defined within the framework of the continuous model of value representation and the continuous interest rate convention: I. the costs of transporting the useful mineral from the mines to the plant, 2. the costs of constructing the transportation links between the mines and the plant, and 3. the costs of maintaining these links over time. Results of the study show a substantial impact of the time value of money on both the processing plant optimal location and the opportunity cost of neglecting the time value of money in the locational considerations.

Jan 1, 1995

General design of pillars to ensure a continuing roof support during ex- traction is discussed. Practical problems associated with pillar extraction are Outlined.

Jan 1, 1974

By K Barns, H Law, T Whebell, P Scobie, T Perkins, J Siliezar, M Larson

With processing a variety of orebodies at Glencore’s Ernest Henry Mining (EHM) has come a changing mineralogy and more complex requirements for treatment in the concentrator. From mid-2013 and into 2014 the grind size required to achieve sufficient mineral liberation for production of a quality concentrate has reduced significantly. What was once a final P80 of 35–45 microns was forced to 20 microns. This has necessitated some creative changes to the flow sheet that previously had a 937?kW Vertimill regrinding a rougher concentrate to 40 microns. EHM is able to utilise an existing M10 000 3 MW IsaMill previously used for magnetite processing, to provide a quick convenient solution without large scale capital expenditures. Operating the Vertimill and IsaMill in parallel in closed circuit was successful at reducing the P80 of the regrind circuit to below 20 microns which increased the final concentrate grade by four per cent. This circuit and intermediate circuits used are discussed. Performance of the Vertimill and IsaMill is compared for efficiency optimisation to improve the overall circuit performance.CITATION:Siliezar, J, Whebell, T, Perkins, T, Law, H, Scobie, P, Larson, M and Barns, K, 2014. From magnetite to chalcopyrite – a story of versatility and efficiency at Glencore’s Ernest Henry mining?operation, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 85–92 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

The problems of the as-built water supply system are discussed. Recent modifications to the collection dams and the water cleaning station using wedge wire screens to resolve these problems are outlined.

Jan 1, 1978

The mining industry is quite often faced with declining selling prices for its products in the face of rising prices for the input cost resources that it uses. Blasting is a key activity within the mining system and has a vital role to play within the Mine to MillTM concept. It is therefore important that blasting makes a positive contribution to mine profit and productivity. There are several variables involved in considering the profitability and productivity of blasting. The rock types and structures, the bench height, the blast hole drill rig specifications, hole diameter, spacing and burden, explosive loading and initiation and blast size fragmentation. Productivity accounting is a methodology which is used elsewhere to give additional insights into the productivity and pricing factors that drive the financial performance of a business. Miners know intuitively that productivity and pricing influence costs and profit, but only with productivity accounting can the dollars involved be calculated. Drilling and blasting are part of a chain of unit operations in a mine. For an owner-miner, drilling and blasting would be considered as cost centres and a productivity accounting cost model approach would be relevant. On the other hand a contractor is likely to consider drilling and blasting as a profit centre, in which case a productivity accounting profit model approach would be appropriate. Both of these will be explained. The paper provides a basic outline of deterministic productivity accounting and demonstrates its application to blasting. Drilling and blasting data from a mine was obtained for a two-month period. The change in productivity and prices was calculated to obtain the dollar contributions from them towards the change in cost. It was determined that although there had been productivity dollar gains these were offset by larger pricing dollar losses, the net effect being that total drilling and blasting costs increased. The productivity accounting analysis gives the facts and the mine is in a position to establish priorities based on knowing the dollar contributions of each input used.

Jan 1, 2001

By Pradhan GK

Blasting is one of the most important operations involved in surface coal mining. The removal of over-burden waste in surface coal mines of India had experienced many improvements in terms of blasting, explosives selection, blast design, equipment selection, deployment. etc. Two case studies of very large surface coal mines have particular importance in their blasting operations. Both these units have been equipped with large capacity excavating machines, hauling units and also have some difficult mining situations. Blasting is done in benches in close proximity to human dwellings and over coal seams developed by underground methods with problems of high wall stability etc, as well. The various steps taken to improve the blasting operations ensure smooth operation of the equipment to meet the targetted coal production.

Jan 1, 1991

By Yates M. G, Rowlands A. T

Most geostatistical techniques applied to the estimation of ore reserves assume relatively unifonn grade and thickness within an ore deposit environment. In shear-hosted mineralisation this rarely occurs. The distribution of mineralisation is controlled by the kinematic and geometric variation within the shear zone. Although the kinematic variation is dependent primarily on the temperature (and consequently the depth) of formation of the deposit, the geometric variation appears to be relatively insensitive to this parameter. Shoot mineralisation is controlled either by the intersection of secoodary shear planes (brittle deformation) or the stretching lineation of the mylonitic fabric (ductile defonnation).Once the shear geometry is clearly identified, it is critical to review the distribution of grade and thickness of mineralisation. The practice of cutting high-grade intersections without reference to the shear model leads to underestimation of the amount of gold in the deposit. High-grade shoots may occur as pipe-shaped bodies within the system; their identification is essential for both resource estimation and mine planning purposes.

Jan 1, 1991