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Initial coal production at Ulan was solely from underground mines. A significant increase in demand for steaming coal in the late 1970's emphasised the need to further expand production and led to the development of the open cut mine which commenced commercial production in June, 1982.During the initial stages of mine planning, feasibility and cost studies were undertaken to determine the most suitable method for coal haulage from the pit. The comparison between a conventional truck haulage system and an in-pit crushing system using a mobile crusher and moveable belt conveyor haulage confirmed that the mobile crusher and conveyor system was superior in every respect for the Ulan mining operations.Technical features and design parameters for the major items of equipment are outlined as well as operating, manning and performance assessments. Minor equipment problems were encountered during initial operation but these have since beenrectified and the plant is now capable of exceeding the design production. Maintenance and energy costs are considerably lower than originally estimated and production efficiencies are continually improving as operators develop new techniques and procedures in the handling of the equipment.

Jan 1, 1985

By Quast K. B

Samples of limestone and micaceous hematite have been ground in a laboratory batch mill using equal weights of either rods or balls. Values of the Schuhmann distribution modulus, a, have been shown to depend on grind time and do not remain constant as often reported. The linear reduction in a with grind time was attributed to a change in grinding mechanisms with time. The product sizing from ball milling limestone showed a bimodal distribution, but rod milling produced a unimodal size distribution. The product sizing from milling micaceous hematite was difficult to interpret due to the major influence of the shape factor on the transition from screen sizing to cyclosizing.

Jan 1, 1995

By Nickelsen J, Theisen KG, Hansen PH

The use of stationary calciners in the processing of aluminium hydroxide has emphas- ized the importance of Bayer hydrate properties with respect to particle breakdown during calcination and subsequent treatment. Test results from calcination of several Bayer hydrates to sandy alumina in the FLS Gas Suspension Calciner (GSC) were obtained in a 250 kg/h pilot plant unit. Particle breakdown during calcination was influenced by content of solid sodium oxalate, trapped in the hydrate particles and operating gas velocities. Owing to the design and operational principles of the GSC it is possible to reduce particle breakdown to at least the same as what is found in long rotary kilns. Other major advantages reviewed are obtained through simplifications in plant design and operation, pointing to low specific power and heat consumption, and generally low production costs, thereby providing an attractive alternative to fluid-bed calciners.

Jan 1, 1981

Underlain by and intruded into the sedimentary rocks of the Transvaal Supergroup the Bushveld Complex is the largest known layered intrusion in the world and contains one of the richest ore deposits on earth. It has been the world's major source of Platinum Group Metals (PGM) since the mid-1900s with Chromite and PGMs the two most economically important components of the Bushveld Complex. The lower group (LG), within the critical zone, consists of seven chromitite layers and it is within this sequence of chromitite layers, the most important target of the lower chromitite group is found, ie the LG6 chromitite unit. The LG6 chromitite unit consists of a chromitite duplex composed of the lower LG6 chromitite layer (Steelport seam), averaging 1 m thick, overlain by a 0.66 m waste parting and a thin 0.34 m thick LG6a chromitite layer (leader layer).Two mining methods are commonly applied in the Bushveld Complex to extract the LG6 chromitite layer package. One method consists of footwall development utilising rail bound equipment to gain access to the orebody and then extracts only the LG6 chromitite layer by means of hand held rock drills and scraper winches. The second method is the use of mechanised equipment to access the orebody on the plane of the ore utilising bord and pillar mining method, which extracts the full mineral resource, ie the LG6 and LG6a layers. Conventional narrow vein stoping is often selected due to the large conventional mining skills base found in South Africa, the perceived cost and dilution implications of utilising mechanised equipment, and the difficulties of using mechanised equipment at dips above 12¦. The driving factor for mechanised mining is the perceived ability to access the orebody quickly and inexpensively, and extract the entire mineral resource package (LG6 and LG6a) while limiting capital expenditure and improving safety.This paper investigates these two commonly applied approaches, highlighting the benefits and problems associated with the two approaches. Comparisons will be made of the two mining methods and recommendations given for the mining engineer to consider before selecting the appropriate mine design.

Dec 6, 2010

A description is given of a detailed examination of a coal bore core and of attempts to predict properties of equivalent "as-mined" coal using the bore core data so obtained. The accuracy of the prediction was measured by testing independently a large sample of coal which was produced under near mining conditions from a site adjacent to the bore core. Very encouraging results were obtained particularly in the prediction of size and ash distributions and washability characteristics of run-of-mine Coal.

Jan 1, 1972

Callie underground gold mine is part of the Newmont Tanami Operations, and is now the primary provider of ore to the Granites processing Mill. The Callie underground mine has produced in excess of 7.6 million tonnes (Mtpa) of ore, since production began in 1998, with a current production rate of 1.9 Mtpa. Callie underground uses sublevel open stoping with extraction through a combination of primary and secondary stopes. The primary stope filling strategy utilises cement aggregate fill (CAF) to allow full recovery of secondary stopes. The Callie backfill operation has had a continuous testing program in place during this time, which has resulted in a great deal of information available for post fill analysis. All CAF placement into primary stopes for Callie has been via surface boreholes and this has given Callie mine an understanding of some of the issues related to borehole design, type of linings to use depending on angle, depth and quantity of fill into stopes. Finally backfill barricades at Callie have undergone a number of changes during the time to optimise the design based on whether CAF or sand fill is used. This paper discusses the CAF backfill practices and testing methods used for backfilling operations at Callie.

Jan 1, 2005

By Hewitt D

A study of two laterite profiles developed on a serpentinite near Rockhampton, shows that loss of Si02 and MgO results in the relative concentration of Fe203, A1203 and a number of minor elements. Serpentine is broken down to form montmorillonite, goethite, quartz and kaolinite. Enrichment of nickel occurs, and it is shown that the element is mainly associated with montmorillonite and serpentine. Highest nickel values are associated with a zone in the profile which occurs at a depth of 10.5-22 metres, and the bulk of the nickel in this zone (42-80%) is associated with the

Jan 1, 1974

By L Torckler, J Hobbins

Favona is a blind low-sulfidation epithermal vein deposit in the Waihi Vein System approximately two kilometres east of the world class Martha Hill deposit that has produced nearly 6.8 M oz Au to date. The Favona epithermal system has surface expression in variously altered and mineralised hydrothermal eruption breccias forming a series of low hills that are windows through post mineral dacites and ignimbrites. The tip line of the Favona vein is about 50 û 100 m below surface with a steeply east dipping principal vein structure carrying numerous hanging wall splays in the upper flatter section and thickening down dip where the vein steepens. Host rocks comprise feldspar phyric andesite flows with minor pyroclastics. Although Favona has a strike length in excess of 1000 m and vein widths up to 25 m over a vertical range in excess of 400 m it was only recently discovered after nearly thirty years of exploration by various companies involved in the Martha Hill joint venture that operates the Martha Mine. Since discovery in 2001 a feasibility study based on 27.5 km of diamond drilling in 83 holes has been completed reporting a reserve of 1 Mt @ 10 g/t Au against a resource of 1.8 Mt @ 10.3 g/t Au. Exploration is continuing with a further 20.5km of diamond drilling completed to date on nearby prospects.

Jan 1, 2004

By Sullivan T. D

The Lochiel Deposit is a large occurrence of soft brown coal about 130 km north of Adelaide. The deposit is undergoing continued evalua- tion of which an integral part was the excavation of a Trial Pit. The Trial Pit was deemed necessary to demonstrate that the deposit may be mined efficiently by draglines and the particular emphasis was on the geotech- nical and hydrogeological aspects of what may be termed difficult mining conditions. The dewatering of the Trial Pit was commenced in September 1986. After considerable planning and excavation was successfully completed in May 1987. The project is unique in terms of its size and technical com- plexity. It entailed excavation of over 230,000 m3 of overburden to an overall depth of 36 metres. The excavated material was utilised for experimentation in a Trial Dump. Included in the Trial Pit design were several novel techniques includ- ing depressurisation drains to improve mining conditions in soil strength materials and the use of vacuum to aid dewatering.

Jan 1, 1988

The Favona Underground Project is located approximately two kilometres east of Martha Mine Open Pit in Waihi, 150 km south east of Auckland, New Zealand.   The underground reserve of 354 koz Au contained in resources of almost 600 koz lies within 600 m of the existing process plant presenting an attractive development target in a challenging environment.   The Martha Mine Open Pit is surrounded by urban housing on the north western edge of Waihi township and the Favona Underground abuts residences on the eastern edge of town. Environmental, community and social licence aspects influence project strategies as the new underground mine extends mining in a town that is planning for closure of current open pit operations in late 2006.   The Favona Underground Project has successfully passed through a detailed feasibility study, the third stage of the five stage Newmont project appraisal system. Methodologies used in the feasibility study and parallel permitting draw on a high level of stakeholder involvement to streamline the development and permitting phases.   This paper discusses the project appraisal process and design innovation required for developing an underground mine adjacent to town.

Jan 1, 2004

By Klinefelter G

The United States Steel Mining Co., Inc. recently experienced a major mine fire at the Cumberland Mine. This mine is located in Greene County, Pennsylvania, U.S.A. and is mining a high volatile bituminous coal seam (Pittsburgh Seam). The mine fire was success- fully controlled and extinguished without loss of life or serious injury to any miner or mine rescue personnel and finally reopened within 40 days of its inception.

Jan 1, 1988

By S C. Dominy

The Bendigo Goldfield is located in the state of Victoria, Australia, and is one of a number of quartz-reef fields that make up the greater Central Victorian Goldfield. At Bendigo gold particles are characterised by their very coarse nature, ranging from below 100 to over 10 000 ¦m in size. Some 60 per cent of the gold occurs in particles greater than 1000 ¦m in size. This characteristic ensures that the mineralisation is very challenging to both sample and evaluate. Diamond drilling provides a measure of geological structure, but is a poor measure of in situ grade, understating it by up to 75 per cent. Drilling combined with on-reef development, bulk sampling and geological interpretation has been used to define Indicated Mineral Resources. For grade control, a balance had to be sought between sample representivity, cost, turn around time and practicality. Sampling of extreme nugget effect deposits generally requires the use of bulk sampling in order to be representative. However, the cost and turn around time is significant. As a result, a 50 kg micro-bulk sampling system has been introduced that attempts to overcome these problems by providing a fast, practical method that can discriminate between ore and waste. As the mine passes into production, grade control will increasingly become dependent upon geological data collection and interpretation.

Jan 1, 2005

By T Connor

Alkali emissions are one of the environmental challenges facing alumina refineries. Queensland Alumina Limited (QAL) is undertaking a number of initiatives to continuously improve its environmental performance. One of these is a program aimed at the reduction of alkali emissions. Alkali emissions originate from a number of sources (eg elevated open tanks), and its level depends on a number of process parameters/ mechanisms (ie splash filling, thermal currents in tanks, streams discharged from a pipe, tank temperatures, atomisation) and climatic conditions (eg wind speed and direction, rain, etc). Under normal operating conditions, there is a continuous low level of alkali emissions from the plant. Certain vessels within the plant have been identified as major contributors to this level of emission, while certain activities within the plant contribute to a temporary elevation (æspikeÆ) of alkali emissions. QAL developed a method using phenolphthalein-treated pads to measure emissions within and outside QAL boundaries. These provide no information about mass emission rates but are important for detecting if alkali material is present. Since mass emission rates are important for determining if improvements in emissions are made, QAL identified the need to design an improved sampling method. Following the development and implementation of a sampling and analysis method to monitor alkali emission concentrations, QAL is conducting a number of feasibility studies evaluating a range of alkali emission reduction options. The alkali measurement method will be used to track and demonstrate progress in this environmental initiative. This paper will discuss the measurement method and emission reduction options being evaluated.

Jan 1, 2005

Many volcanoes in western Melanesia have tectonic settings and rock compositions that do not conform to conventional models of arc- trench systems. Part of the reason for this may be that in an environment of rapid tectonic change mantle source regions bear the imprint of former subduction even though subduction has now ceased. Results bearing on this concept and on other important aspects of Plelit nesian v ican ism and tectonics, were obtained in 1982-1986 from >e,:eral marine - geoscience studies in the re,,ii n

Jan 1, 1987

By Blackham M

West Wallsend No. 2 Colliery is a new mine that is presently being developed in the New- castle Coalfield by J. & A. Brown & Abermain Seaham Collieries Ltd., a subsidiary of Coal & Allied Industries Ltd. It is situated near Barnsley and is some 15 miles by rail from the port of Newcastle. The mine will produce coal from both Bore- hole and Young Wallsend seams. The Borehole seam has a working seam thickness varying from 7 ft to 5 ft while the Young Wallsend seam presents a choice of two distinct working thick- nesses, i.e. 5 ft. or 8 ft, the upper 3 ft containing much high ash material. The inter- seam interval varies from 10 ft on the western edge of the area to more than 70 ft in the central portion. The Borehole seam lies at a depth varying from 550 ft to 750 ft and the overlying surface terrain is gently undulating bushland with limited surface development.

Jan 1, 1972

By R Wolff

One critical factor in open pit mining projects is the estimation of the recoverable reserves. The reason for this is that at the valuation stage there is a lack of information about future metal prices and production costs. Consequently, the estimation of the recoverable reserves needs to be done based on a fixed break-even cut-off grade (BECG), in which fixed expected metal prices and production costs are assumed throughout the operating life of the mine (OLM). In this paper, an alternative technique for estimating the recoverable reserves of an open pit mining project is presented and explained in detail. The main characteristic of this technique is that it estimates the recoverable reserves of the project using mining costs as reference: this is done due to the fact that mining costs are easier to model than metal prices. Another important characteristic of this technique is that it uses the uncertainty of the geology of the orebody, given by simulations of the deposit, to make final strategic decisions, such as the selection of the operating life of the mine and the optimal production rate, which minimise the risk of not achieving future production targets while maximising the upside potential of future rewards. As it will be shown, the final outcome of the proposed technique is the generation of a robust open pit design, that include cutbacks and ultimate pit limits, called the marginal open pit mine design (MOPMD). One characteristic of the MOPMD is that, at each production period, it will be characterised by their respective geological uncertainty, given as probability distributions of ore, waste and metal quantities, and by marginal economical project indicators, such as cut-off grades and metal prices, among others. The details follow in the paper.

Jan 1, 2006

By B, T Norgate, S Sanetsis, R Davidson

Global cement production accounts for about five per cent of man-made CO2 emissions (WBCSD, 2002). Such operating practices will increasingly be considered unsustainable, unless significant reductions in environmental impact can be realised by the industry.Slag is a high volume waste product from ironmaking, with about 300 kg of slag being produced per ton of iron. Critically, one ton of slag waste, if used as a replacement feedstock for Ordinary Portland cement (OPC), can prevent around one ton of emitted CO2 since no calcining is required. Slag cement blends can also show superior properties compared to OPC, such as lower heats of hydration and higher late strengths, but more development is needed to overcome their low early strengths. Rapid quenching of molten slag is required to produce æhydraulically-activeÆ binder when reacting with OPC; but water quenching can also require between five to ten tons of water per ton of slag at the plant. æDryÆ granulation (atomisation) is emerging as an alternative technology, the resulting solid product does not require drying, and possibilities exist for recovering heat energy from the hot slag.CSIRO Minerals has well-developed skills and equipment in pilot-scale pyrometallurgical treatment, and granulation of molten slag, including traditional wet, and also dry methods. Techno-economic desktop studies can also be used to help quantify factors such as value-adding of treated waste products, potential reductions in CO2 emissions and carbon credits, reductions in water consumption, and the possible decreased energy costs associated with fine grinding of dry slag granulate.The authors will present preliminary results from slag atomisation/dry granulation testwork (0.5 - 2.5 kg scale) and associated modelling studies, conducted using a æsyntheticÆ and industrial ironmaking slag. Outcomes from a techno-economic study on production of cement utilising wet or dry atomised slag granulate will also be discussed in detail.

Jan 1, 2004

Renison Limited produces high and low grade tin concentrates at an annual rate of 5000 tonnes of contained tin metal. In spite of the fine average cassiterite grain size, emphasis is placed on gravity concentration methods to produce a high grade final product. Cassiterite flotation is considered and operated as a gravity circuit scavenger responsible for approximately 15 percent of recovered tin metal as a fine grained low grade concentrate. Metallurgical problems mainly result from ore-type variations which may be aggravated by a number of circulating loads. The rationalisation of circuitry is being studied to provide more effective control by operators and to allow exploitation of current control and modelling techniques.

Jan 1, 1977

By Yambu J, Titus K

Geotechnical investictations and monitoring have been integral to development of the Porgera Gold Mine. The steep, unstable terrain has required a program for monitoring of slopes and foundations which includes survey stations, borehole inclinometers and piezometers. Case studies of the Maip Pass landslide, Yakatabari land-slide, Anawe Plant Site CIP pond excavation and batter, and a load test study for mine waste dumps are presented.Monitoring is needed to ensure that geotechnical risk is kept to a minimum. A vigilant program will be required for the life of the mine.

Jan 1, 1994

By Ramani R. V

In this paper, a comparative performance evaluation of geostatistical, spectral, and fractal methods is made for short-scale variability prediction. The algorithms compared are: sequential Gaussian simulation method; a random fractal algorithm based on the generalised stochastic subdivision method; and a spectral simulation approach adopted for direct multi-dimensional simulation. The data for this study have been obtained from a mined out coal property. As this property was being mined, a 7315 m by 7315 m (24000 ft by 24000 ft) coal block was extensively sampled at an approximate spacing of 107 m (350 ft) and the 60-ton samples were analysed for sulphur in the 1.50 float gravity fraction. This data set is used here with the three methods to generate the simulated realisations, which are analysed for semivariogram reproduction and for simulation errors. Although all three methods converge to the true semivariogram in an average sense, the coefficient of variation of the average semivariogram for the Fourier integral method is minimum. The realisations generated by the sequential Gaussian method have minimum mean simulation error. The choice of a simulation method based on variability reproduction and simulation errors remains difficult.

Jan 1, 1995