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Cerro Matoso (CMSA) in Colombia produces ferro-nickel from lateritic ore containing approximately three per cent nickel, using a Rotary Kiln - Electric Furnace (RKEF) process, in which the calcining of the mineral within the kiln is second in importance only to the smelting of the mineral in the Electrical Furnace. This article discusses the installation and operation of an expert system to control the kiln of CMSA. In the CMSA process, the run-of-mine ore is crushed, homogenised, dried and mixed with a small percentage of coal, before being heated up to 900¦C in a rotary kiln in the presence of natural gas mixed with air in a controlled proportion (air/gas constant ratio). The final objectives of the process are the following: ò To reduce to a minimum the iron and nickel oxides in order to convert these into metallic ions; this is a reduction process to facilitate largely the smelting in the electric furnace. Since the reduction is made with natural gas, it is much more economical than the subsequent complete reduction in the electric furnace, since electrical energy is much more expensive by unit of processed mineral. ò To heat the mineral as much as possible to facilitate the subsequent smelting. ò To eliminate totally the moisture content of the ore. An expert system with fuzzy logic was commissioned in 1994 for the control of the kiln and it has operated with good results ever since.

Jan 1, 1996

By K Peters, C McKenzie

New Zealand has an established history of gold production beginning with the gold rushes of the 19th century in the Coromandel, Nelson/Marlborough, West Coast and Otago regions. Despite this, the number of significant modern hard rock gold operations has been limited in recent years due to a lack of sustained exploration capital and not limited geological prospectivity.The New Zealand Government is actively encouraging explorers to invest in New Zealand through a series of targeted promotional visits, more importantly through the acquisition of precompetitive regional geophysical data. Data collection has been completed over the prospective Northland epithermal district and a large portion of the South IslandÆs west coast that is prospective for both orogenic gold and intrusive related gold.Analysis of new data has been an important component in aiding the generation of exploration targets from prospectivity modelling. Determining the prospectivity of an area involves reviewing all the available data and analysing it with respect to the most up-to-date mineral system model for the mineralisation style of interest. Using the weights of evidence modelling approach, the most prospective areas for epithermal gold-silver, orogenic gold and intrusion-related gold have been identified. The key exploration parameters relevant to each mineral system are first represented spatially and then statistically combined into a single prospectivity map. New potentially economic deposits could be found by focusing exploration on targets identified from these models. The prospectivity modelling approach can greatly reduce the risk involved in mineral exploration.CITATION:Peters, K and McKenzie, C, 2013. New Zealand gold potential - using mineral prospectivity modelling to evaluate gold-bearing mineral systems in an underexplored country, in Proceedings World Gold 2013 , pp 479-486 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

The following is based on two examples of emission control with coal fired power stations as practised in Germany at Heilbronn Block 7 power station and the Rheinbraun coal combined power station with integrated high-temperature Winkler system (HTW). Heilbronn Block 7 demonstrates the successful emission control of sulphur and nitrogen oxides and the (HTW) system the reduction of the specific carbon dioxide emission. Both were sparked off by legislation which demanded certain emission control standards. Since the early eighties environment protection has been a matter of heated public debate in the European Community. A recent survey in Germany showed unemployment as being the only subject matter more frequently in the minds of people than environment protection. A new kind of forest devastation in areas away from industry has caused investigations by several government departments and private enterprise. Because of lack of conclusive evidence so far, the principle of PRECAUTION has replaced the CONCLUSIVE evidence as a base for new legislation concerning the environment. The new legislative standards for nitrogen oxide emissions in Germany for example have reduced NOx emissions of power stations from 1000 mg NOx per cubic metre of flue gas in the beginning of 1983 to 200 mg NOx per cubic metre of flue gas in April 1984. These new standards were enshrined in legislation when research provided some evidence linking nitrogen oxide emissions through photo-chemical reactions with forest devastation. Thirty European countries signed a treaty in 1983 expressing their concern about air pollution and their willingness to co-operate with each other in controlling large scale emissions.

Jan 1, 1991

Discovered in 1896, the Sons of Gwalia orebody is located in a ductile mylonite zone within a sequence of Archaean pillow metabasalts and minor metasediments of greenschist facies which are variably sheared.The ore zone has good continuity, being 110 m wide and 500 m long, dipping 45 degrees east and plunging 70 degrees to the south to a depth of 1500 m downplunge. A strongly-developed foliation is present together with a prominent lineation paralleling the plunge. The mylonite zone consists of unmineralised chlorite schist and a 'U' shaped mineralised zone of chlorite-sericite schist with varying amounts of quartz-carbonate as veins parallel to foliation, boudins, and locally as massive quartz-carbonate. Pyrite is the dominant sulphide present.Grade control utilises RC holes on a 10 m x 10 m pattern, with infill blast rig holes 5 m deep where necessary.Some visual control of ore boundaries is present and, combined with good ore continuity and a knowledge of the structure of the orebody, enables cost-effective grade control to be achieved. To-date, over three million ounces of gold have been produced from the orebody.

Jan 1, 1993

By Sims D. A

This paper primarily describes the application of geology to the different mining methods employed in a large underground mine. The steeply dipping stratiform Silver/Lead/Zinc mineralisation at Mount Isa include up to 28 mineable orebodies. The orebodiea are mined by cut and fill, sublevel benching and sublevel open stoping; the method chosen depending mainly on orebody geomechanics.The sources and methods of data collection, and the interpretation process undertaken, are described. The paper emphasises the different geological input required, by each individual mining method, to provide the necessary production and strata control. This input contributes significantly to the success and efficiency of the operations.

Jan 1, 1990

Slope stability is a critical safety and production issue for open cut mines. The æslope stability radarÆ has been developed to remotely scan a rock slope to continuously measure the movement of the face. The system can detect and alert movements of a rough wall with sub-millimetre precision, and with reliability and resolution. The advantage of the slope stability radar over other monitoring techniques is that it provides full area coverage without the need for mounted reflectors or equipment on the wall. In addition, the radar waves adequately penetrate through rain, dust and smoke to give reliable measurements, 24 hours a day. The measurement technique is tolerant of vibrations and overcomes the need for a highly stable footing required by traditional surveying systems, making it easy to move from one location to another. The system is self-powered and designed for minimal maintenance. Radar displacement images, co-registered with digital photography images, are transferred from the radar site in the pit to the mine office via a radio telemetry link. Custom-written software provides mine managers and geotechnical engineers with a complete picture of slope movements over defined time intervals. The time-history of the movement of any selected points or regions on the slope can also be displayed. Also provided is the ability to set movement thresholds that will trigger alarms at the radar site or mine office. The system has been used at numerous coal and metalliferous mines in Australia, and has provided real-time monitoring of slope stability during active mining operations. More than 20 rock wall and spoil failures have been captured by the system, and on every occasion adequate warning was provided to mine operators. The high level of movement precision and broad area coverage of the rock face provides a better understanding of the geodynamics, which leads to extra warning time. This technology enables a radical change in the management of risks in open cut mining operations.

Jan 1, 2003

By M Miller

Operators of nickel laterite pressure acid leach and gold pressure oxidation technology frequently employ a series of steam condensing heaters to preheat the leach feed slurry. The heaters are an economic pinch point û although the thermal performance of the heaters is critical to overall process viability and operating cost minimisation, they are also a significant capital item and must be sized accordingly. Despite this, discussions of the factors underlying heater design are conspicuously absent from technical literature, and existing operations feature a conflicting range of heater sizes and configurations. This variety would suggest that at least some of the chosen heater designs are oversized. As part of its detailed design stage, the Ravensthorpe Nickel Project (RNP) constructed and tested a pilot plant heater to develop an understanding of the heating process and to ensure that the RNP heaters were appropriately sized. This testwork used RNP slurry at design density and viscosity on a 450 mm diameter, 6500 mm high column. The pilot plant testwork demonstrated the intrinsic efficiency of the direct steam condensation heating process, which was essentially independent of slurry density and viscosity. Presence of non-condensable gases in the steam phase decreased the heat transferred in certain circumstances, but heater performance remained consistent with thermodynamic limitations. Stagewise heat transfer within the column was rapid, and suggested either a very high slurry surface area or excellent heat transfer within the slurry phase. While the testwork did not set out to distinguish between these effects, physical evidence pointed to droplet formation in the inter-tray shower zone, giving a high heat transfer area. For scale-up purposes, the key facts were that the heat transfer rate was not limited by using high viscosity slurries and heaters could be designed using the principles applied to the smaller of those in existing operations. This paper discusses existing slurry heater designs, the current understanding from open literature, the pilot plant testwork, results and analysis, and scale-up to commercial sized equipment.

Jan 1, 2005

Comparatively recent Tasmanian legisla tion established a series of rigid control standards for environmental protection just as ma spectacular expansion of the mining industry was nearing completion. Upgrading existing protection to obtain the necessary licence to operate under these new regulations required further major works and involved a considerable outlay of non- productive capital at a time when escalating costs and falling metal prices were straining economic efficiencies to the limit. Late in 1974 a major environmental protection scheme was commissioned by the Electrolytic Zinc Company of Australasia Limited at Rosebery on the West Coast of Tasmania. This 4 million dollar project was specifically developed by the Company ahead of and to meet the new standards for control of total effluents discharged from its zinc-lead -copper-pyrites mine and concentrator.

Jan 1, 1977

The Nickel Rim Depth Cu-Ni-PGE deposit, discovered by Falconbridge Limited in 1993, illustrates several trends in exploration in the Sudbury area. Recent discoveries tend to be deep, high grade, footwall hosted, close to or straddle property boundaries and made using a multi-disciplinarian exploration approach that integrates economic considerations with geology, metal geochemistry and geophysics (borehole EM). The Nickel Rim deposit occurs down dip of Inco's Victor Deep deposit (4.2 million tonnes at 2.25 per cent Ni, 7.30 per cent Cu) in the eastern margin of the Sudbury Igneous Complex (SIC) at a depth of 2650 m. Before commencing drilling an economic evaluation was done to determine the minimum size needed to be economic at the expected depths and determine the expected value of an exploration venture. The subsequent surface exploration program discovered a drill indicated, undiluted mineral inventory of 1.6 million tonnes of 1.58 per cent Ni, 10.13 per cent Cu, 4.17g/t Pt and 3.50 g/t Pd including 519 000 tonnes of 4.13 per cent Ni, 25.53 per cent Cu, 9.76 g/t Pt and 8.42 g/t Pd. The deposit is hosted by gneiss, migmatite, gabbro and pseudotachylite (Sudbury Breccia) 100 m below the base of the SIC.

Jan 1, 1996

By Moxon N. T

A series of low shock energy water resistant emlulsion based explosives have been developed by combining inert materials, such as Perlite P500, into the formulation. The material handling, water resistance and explosive properties of these mixtures were determined as a function of inert additive type, density, charge diameter and emulsion base. Of the emulsion bases tested Emulite produced the best and most stable low density mixtures ranging in density from 0.8 to 1.35 g/cm3 producing velocity of detonations (unconfined) ranging from 3000 to 5500 nits. The mixtures could be detonated successfully at these densities at diameters as low as 25mm. Low shock mixtures formed by combining Emulite with Perlite P500 were successfully trailed at the Cadjebut zinc mine in Western Australia. The performance of the explosive, at three densities, was monitored using both continuous and point to point VOD techniques. The fragmentation produced by the blasts were compared by photographic analysis. During this trial the low shock emulsion mixtures were shown to be as effective as the currently used explosives (packaged emulsion) at a significantly reduced cost.

Jan 1, 1990

By S Hughes

The smelting of concentrates and secondary materials has been subject to increasing challenges in recent years due to declining grades of feed materials, increasing impurity levels and ever more stringent environmental regulations. In addition there has been a growing focus on maximising the efficiency of energy usage and recovery of values. New opportunities have been created with rising metals prices and improved systems for the collection of secondary materials, giving rise to a need for more flexible process solutions.This paper focuses on a number of specific cases where a process solution has been developed using the Outotec« Ausmelt Process to meet particular feed material challenges and overcome limitations inherent when employing traditional pyrometallurgical processes.The first case involves the development and commercial implementation of a smelting process to recover values from zinc smelting residues typically deposited into dams as a waste product. The second case describes the application of the Ausmelt process for the smelting and converting of secondary copper feed materials, including e-waste. These materials contain a wide range of metals and plastics and need to be processed appropriately to maximise the recovery of values whilst avoiding environmental problems. The third case study covers the smelting of nickel concentrates containing elevated magnesia levels as well as nickel bearing catalysts with high alumina content, neither of which can be readily processed when employing traditional pyrometallurgical technologies. CITATION:Hughes, S, 2013. Pyrometallurgical process solutions for complex raw materials, in Proceedings MetPlant 2013 , pp 519-530 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

During the later part of 2007 I was lucky enough to visit the Atlas Copco facilities in Sweden, and to see first hand what a large and diverse company Atlas Copco is. The reason this paper calls the Atlas Copco experience a bonanza is that it means a source of great and sudden wealth or luck; a spectacular windfall or a rich mass of ore, as found in mining. I think this aptly describes the scholarship as it has greatly increased my wealth of knowledge of the mining industry. This paper intends to encourage all those eligible to apply for this fantastic scholarship opportunity, and seeks to thank all those involved who made this scholarship the amazing experience that it was. Atlas Copco produces most of its Swedish products in the town of +rebro, and it was here that I spent most of my time, visiting the Underground Rock Excavation group, the Surface Mining Equipment group and Rocktec. I also travelled around Sweden and was able to visit one of OricaÆs manufacturing plants, the Secoroc groupÆs manufacturing plant, the Geotechnical Drilling and Exploration group as well as being fortunate enough to visit the LKAB mine in the Arctic Circle in Sweden. The trip was not all information on Atlas Copco products and services however; I was able to go to the Ice Hotel in JukkasjSrvi and drink Absolut Vodka out of ice glasses, go on a reindeer safari (as well as eat them!), sample the fine meat from a moose, drink local schnapps, attend the Atlas Copco Christmas party, wander around the wonderful city of Stockholm and generally immerse myself in the great Swedish culture.

Jan 1, 2008

About 3km2 of the central Luise Caldera, in which the Lihir orebody is located, is geothermally active wit.lj gas seeps and fumaroles, and in some areas, a water table at boiling point.The proposed mine, adjacent to Luise Harbor, will be excavated to more than 200m below sea level and will extend into the geothermal system to depths at which current rock temperatures are 170¦C.

Jan 1, 1994

By Sheard SN, Tucker DH

Sampling procedures are an important aspect of geophysical exploration survey design. It is good practice that the selection of survey parameters ensures that the signal to noise ratio is optimised, while minimising survey cost.Sampling considerations for any geophysical method include the size of the target, scale of observation, aliasing associated with station and line spacing, nature and extent of overburden, and the presentation of data.As a guide to survey design, the specifics are discussed for three geophysical techniques in common use in mineral exploration; these include the magnetic method, transient electromagnetics and induced polarisation.

Jan 1, 1976

By J Hadjigeorgiou

Underground mines often rely on ore pass systems to ensure the transport of ore and waste. Consequently, it is important to ensure the smooth operation of such systems. Ore pass degradation that may require rehabilitation results in production delays and high operational costs. The occurrence of hang-ups within an ore pass also leads to disruption of ore production. There are important safety concerns when worker intervention is necessary to re-establish material flow in the ore pass. In order to facilitate the design of ore pass systems, mining operations often rely on past experience, or semi empirical guidelines. This paper describes recent efforts to establish a comprehensive database on current practices; encountered operational problems and solutions in ore pass design in Quebec underground mines.

Jan 1, 2003

By Hunter GW

This paper gives an account of the filling system at Mount Isa from surface fill production to stope discharge underground. A brief explanation of the surface facility and reticulation is given prior to the discussion on aspects of underground reticulation. These include fill hole types, pipe and breastplate installation, wear characteristics, etc. The different types of fill and their respective applications is mentioned as a prelude to a general overview of the mining considerations associated with fill placement and its role in the long term planning strategy at Isa Mine. Some practical aspects of stope preparation and filling procedures are outlined for the various stoping methods. Finally a brief outline of future fill developments is given.

Jan 1, 1982

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

By Dagbert M, Belisle J. M

Several packages for the estimation of porphyry type deposits exist and produce acceptable results. Recently, however, the need for really trying to obtain maximum information from drill holes has prompted the generation of geostatistical solutions to the problem of reserve calculation. It will be shown that an understanding of a few key points is necessary in order for these solutions (variogram analysis and kriging) to he really ptimal. The most important new fact to be ecognized in open pit ore reserve estimation is that block models do not give an accurate rediction of ore tonnage when a cut-off is pplied but often yield an overestimation of p to 25%. When checked against extensive roduction records, geostatistical methods provide a practical solution to this problem. t now seems that the model used here gives he best possible results. Inasmuch as all arge deposits present very similar geostatis- ical characteristics only a few days of work re necessary to produce a complete inventory f these. The techniques used will be demon- trated using examples from five deposits and pecial emphasis will be given to the accurate rediction of tonnages of ore and waste using he new "transfer function" technique of G.

Jan 1, 1977

Christmas Island contains large deposits of phosphate minerals varying from high-grade calcium-phosphate (apatite) to lower grade iron and'aluminium phosphate (crandallite/millisite). The surface material is dominantly C-grade (Fe/Al) phosphate profiling into B-grade, a variable mixture of C- and A-grade ores, before reaching the high A-grade phosphate (apatite) which overlies a limestone Karrenfeld Base formation. A-grade ore is the basic phosphate used for the manufacture of superphosphate and phosphoric acid, whilst B-grade contains amounts of iron and aluminium which are unacceptable for these acidulation processes. Research into methods of separating the finer iron and aluminium phosphates from the coarser calcium phosphates has led to the development of wash-screen processes enabling recovery of 50 to 60%, as A-grade phosphate. Developmental stages included laboratory investigations, mineralogical studies, pilot tests leading the initial 20 tph prototype production unit and the current 100 tph production wash/screen plant, commissioned early in 1970 at Christmas Island.

Jan 1, 1971

By Geisler P, Sutherland P

The technical limits for high-pressure transport of large particle solids by means of sludge pumps, piston pumps or the like lead to the development of the pipe-feeder system. The pipe-feeder is a type of pressure lock in which the high-pressure pump itself is not in contact with the solids. Simultaneous operation of the three chambers with corresponding control of the valves allows continuous flow in both the primary and secondary circuits. Initially the pipe-feeder was used only for the transport of solids. Today it also operates with great success in central mine cooling systems, serving as an alternative for high-pressure/low-pressure heat exchangers or Pelton systems. In addition to the technology applied up to now, the pipe-feeder is also capable of transporting ice slurry, thus increasing cooling output consider- Ably.

Jan 1, 1991