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By S. Henley

Paper presented at a meeting on: Artificial intelligence in the minerals sector, held in Nottingham, UK, 20 April 1993 (original title: The database: a pre-requisite for large-scale use of AI in mining). Artificial intelligence is a term which has been widely applied to different techniques including rule-based systems using inductive and deductive logic algorithms, neural networks, learning systems and genetic algorithms. In principle it should be applied to adaptive statistical techniques. Some of these applications have been coded in languages which are specifically suited to the novel requirements of AI but are not easy to integrate with more traditional computing methods. Efforts have been made to bridge the gaps, particularly with database management systems and such efforts at integration should provide the key to future success in the application of AI. A field which has been termed "knowledge engineering" cannot be credible as such if it fails to provide easy access to raw materials of "knowledge" i.e. the data residing in databases. In the mining industry there are a number of significant areas in which AI could usefully be applied throughout the industry, but its advance is slow because of the lack or inefficiency of such database links. Current development of object-oriented database systems for geology and mining holds out hope for such integration in the foreseeable future

Apr 1, 1994

By A. K. Tripathy, P. K. Pattnayak, H. S. Ray

The effects of water addition on the solid-state reaction between Cr2O3 and Na2CO3 at low temperatures (up to 873 K) were investigated to determine its possible influence on the reaction rate and the degree of conversion to soluble chromate. Experiments at high temperatures were conducted for comparison. It was found that adding water to the mixture before roasting enhanced both reaction rate and yield significantly. The reactions followed the Lesokhin-Tempelman equation at low temperature and the Ginstling-Brounshtein equation at above 973 K; the respective activation energies were 95 and 22 kJ/mol

Jun 19, 1905

By A. M. Tunstall, N. Djordjevic, H. A. Villalobos

The damage zone behind a typical smooth-wall blast in the open pit was assessed by visually examining diamond drill core to identify blast-induced cracking, mapping core rock quality designations to identify changes in fracture frequency and conducting uphole seismic testing to determine changes in rock mass characteristics. The results from the three techniques show reasonable correlation. They suggest that major damage, in the form of fracturing of intact rock, occurs at least 7 m behind the smooth-wall blast and significant damage, in the form of opening and extension of calcite-filled fractures, at least 12 m from the blast. At greater distances the dominant damage mechanism is the loosening of existent joints within the rock mass. In the trachytes at El Soldado these damage mechanisms correspond to peak particle velocities of 2 000, 900 and 500 mm/s respectively

Jun 19, 1905

By S. Kelebek, J. A. Finch, Zhenghe Xu, S. R. (Ram) Rao

To improve SO2 emission compliance, pyrrhotite from Sudbury copper-nickel ores is being depressed with DETA. To understand the mechanism of depression, the role of complexing in controlling metal-ion activation of pyrrhotite was investigated. DETA was found to remove Cu and Ni ions but leave hydrophilic ferric species on the pyrrhotite surface. The metal:DETA ratio appeared to be 1:2. Cu was more readily removed than Ni, but the combination of DETA with sulphur dioxide was equally effective for both metal ions. Certain combinations of DETA, Ni ions, xanthate and dithionite (S2O4) or dithionate (S2O6), as representative derivatives of SO2 in water, produced hydrophilic precipitates. These may enhance pyrrhotite depression

Jun 19, 1905

By P. H. Davenport, L. W. Nolan

Paper presented at the 28th International Geological Congress held in Washington DC, July 1989 (International geochemical mapping sessions). Geochemical mapping provides a direct approach to delineating areas of epigenetic mineralisation and for relating the regional distribution of this mineralisation to an overall tectonostratigraphic and structural framework, as well as to extensive areas of hydrothermal alteration. Organic lake sediment is a widely available and effective sampling medium for regional geochemical mapping in Newfoundland, that has proved to be valuable in Au, Sb and W exploration

Jul 1, 1991

By B. M. England, M. V. Swain, N. Bristow, R. D. Dukino

The toughness and fracture mechanisms of ores with significantly different microstructures from Yandi, Koolan and Mount Whaleback were studied with a view to understanding their degradation behaviour. Bulk fracture toughness was determined by the 3-point single-edge notch beam test and the results interpreted using Weibull statistical analysis; indentation fracture mechanics was also used to measure fracture toughness of the different mineral forms and to understand their response to contact fracture

Apr 1, 1995

Paper presented at the UK minerals industry conference and published in: Minerals extraction towards the millennium. UK minerals industry conference, 3-5 April 1995, University of Leeds. London: Institution of Mining and Metallurgy, 1995. The various types of risks that arise in minerals industry projects are usually financial, technical, or environmental, and the key to valid risk analysis is complete integration of all risks, both within and between categories. Geographical information systems (GIS) and geostatistical simulation methods can provide a means of integrating data and conducting realistic risk analyses. Risk can be quantified but there are limitations to numerical approaches to risk assessment. Realistic quantification requires adequate models of the processes that give rise to risk. Risk perception must also be taken into account when conducting risk assessment and reporting the results, especially in public forums. The modelling and visualisation capabilities of a combined GIS/simulation system can provide the means of dealing with perception in risk analysis

Jun 19, 1905

By Xuejing Xie, Tianxiang Ren

Paper presented at the 28th International Geological Congress held in Washington DC, July 1989 (International geochemical mapping sessions). Standardised stream-sediment sampling procedures have been used in mountainous and hilly terrains. Special sampling procedures were developed for application in remote environments, such as high mountains, desert, semi-desert, karst and loess-covered regions. The diversified analytical methods used in more than 20 analytical laboratories participating in the project have been unified into two multi-element, multi-method analytical systems. A unified data monitoring procedure was developed based on primary and secondary standard samples. To date the project has covered about 4 000 000 km2 and the aim is to complete the coverage within the present decade

May 1, 1991

By E. Niehuis, J. Y. Kim, H. G. Cramer, S. L. Chryssoulis, K. G. Stowe, C. Bendel

TOF-SIMS was used to detect, identify from parent molecular ions and determine the relative concentrations of collectors sorbed on the surface of mineral particles in concentrate and tailings samples from three Canadian concentrators. In the Kidd Creek Zn circuit, sphalerite lost to tailings carried on average a quarter of the amount of isobutyl xanthate present on that recovered to Zn concentrate; amyl xanthate, which is not reported as added to the circuit, was also detected on floated sphalerite and pyrite. At Brunswick, sphalerite particles lost to the scavenger tailings had ten times less amyl xanthate and isobutyl xanthate than those recovered to the Zn final concentrate, while both xanthates were detected on sphalerite floated to the Cu-Pb cleaner circuit. At Matagami, significantly more isopropyl xanthate and isopropyl dithiophosphate were detected on sphalerite recovered to the final Zn concentrate than on that lost to the Zn rougher tailings

Dec 1, 1995

By Qing Wang, H. Sevim

Belt network simulators are the most widely used models in the design of belt networks. The simulators developed in the past two decades are reviewed and their limitations are discussed. To overcome these limitations and to provide a design model that can be used efficiently in real-life applications, a comprehensive non-simulation model has been developed. The features of this model are briefly discussed. A real example is used to demonstrate the model's superiority over belt simulators

Sep 1, 1991

By R. G. Garrett, A. J. S. Geddes

Paper presented at the 28th International Geological Congress held in Washington DC, July 1989 (International geochemical mapping sessions). The 1986 geochemical survey was successful in recognising all the previously known mineral occurrences of significance in Jamaica, in outlining areas not previously believed to have mineral potential and in stimulating fresh appraisals of old occurrences in terms of their potential for new commodities. This has resulted in a very significant increase in mineral exploration activity in Jamaica

Jul 1, 1991

By M. J. Scoble, L. M. Daneshmend, C. Hendricks

Paper presented at a meeting on: Artificial intelligence in the minerals sector, held in Nottingham, UK, 20 April 1993. An attempt is made to relate emerging technologies to education and training requirements by examining the nature of the Canadian mining industry's human resources. Particular attention is given to the trends evident in mine automation and their likely impact on instructional needs. The characteristics of "computer-aided instruction" systems are reviewed and related to the implementation and support of mine-wide monitoring and communication networks, which are seen as fundamental to the eventual automation of underground hardrock mines

Apr 1, 1994

By A. G. Pasamehmetoglu, N. Bolukbasi, O. Koncagul

A study has been undertaken to establish the relationships between the O&K wedge test cutting resistances and the geotechnical parameters of rock materials in the context of bucket-wheel excavator operation. Prediction equations were formed to estimate the cutting resistance from the geotechnical parameters by multiple regression analysis. The cone indentor index, uniaxial compressive strength and Shore hardness parameters have been found to be the most significant predictors

Sep 1, 1991

By S. C. Tennant, G. M. Steed

Paper presented at Mineralisation in the Caledonides, the Mike Gallagher memorial meeting held in Edinburgh, 27-28 June 1996. Immobile-element lithogeochemistry is providing a detailed chemostratigraphy of the submarine Ordo-Silurian volcano-sedimentary sequence. Primary lithologies and magmatic affinities of the sericitised and silicified volcanics are determined from binary plots of Nb, Zr, Y, TiO2 and Al2O3, while mass-change calculations using immobile-element anchors can identify and quantify zones of significant hydrothermal alteration. Stratiform polymetallic mineralisation at the western margin of Parys Mountain, around the Penymynydd fault zone, has been shown to have a distinct hanging-wall and footwall stratigraphy. These ore zones are probably part of a homoclinal, north-younging volcano-sedimentary sequence. The apparent stratigraphic complexity results from primary lithofacies variations and pervasive alteration, with the modifying role of the Caledonian orogeny much less than previously suggested

Jun 19, 1905

By A. Ersoy, M. D. Waller

The principal factors which require consideration in predicting drilling rates are the bit-type, the bit operating parameters and the characteristics of the penetrated rock. A single index is not a sufficient basis for predicting performance. A variety of rock types were drilled in the laboratory with polycrystalline diamond compact (PDC) and impregnated diamond core bits using a fully instrumented drilling rig at different rotational speeds and with a range of weights on the bit. Quantitative determinations of a wide range of textural, mechanical and intact rock properties were also made. Multi-variable linear regression analysis was then used to develop predictive models of rates of penetration from the operating and rock property data. The models have been verified by statistical tests. The analysis indicated that the models for the pin and hybrid PDC bits have potential for practical application. However, although the model for the impregnated diamond bit appears to be reasonable from a purely statistical point of view, it may not be satisfactory for drilling uses as it is based on two measures of rock hardness alone. The application of multiple regression analysis to PDC drilling performance is novel and the technique shows promise for the prediction of rock drillability with PDC bits. The ability of the technique to provide a mathematical characterisation of the performance of new drill bits in specific rocks may prove to be of value to drill manufacturers and users

Aug 1, 1995

By D. R. Wardrop, G. Walton

Paper presented at the UK minerals industry conference held in Leeds, UK, 3-5 April 1995. A description is given of the approach that has been taken to the design of the 550 000 000 t superquarry with a planned life of 60 years that is proposed for development. The quarry has been designed to replicate a corrie and a sea loch and will include excavated slopes more than 570 m high. The main geological and physical controls on the layout and the choice of development method are outlined. The operation phasing is presented and the geotechnical constraints on slope design and the feasibility of alternative quarry limits are discussed. Environmental considerations have been dominant in planning and the quarry has been specifically designed for closure

Jul 1, 1996

By M. A. Leosson, S. H. Bottrell, R. J. Newton

Sylvite at Boulby is mined 1 140 m beneath the sea and the mine suffers from the influx of water. This is of two kinds: persistent flows originating in the Sherwood Sandstone aquifer and entering the evaporite sequence through fractures in the intervening mudstone, and impersistent flows which are transient in nature and of uncertain origin. Water from the overlying sandstone has become enriched with NaCl and large amounts of KCl and some Mg and Br have been added by interaction with the evaporites. Waters from the transient flows are isotopically distinct from those in the Sherwood Sandstone, being enriched in H and O. They are also saturated with respect to halite and sylvite, but have higher K/Na than the persistent flows and are much more enriched in Mg and Br

Jun 18, 1905

By I. D. Nock, R. M. Parkin

Paper presented at a meeting on: Artificial intelligence in the minerals sector, held in Nottingham, UK, 20 April 1993 (original title: Knowledge-based condition monitoring of cone crushers). A large proportion of the electricity used by the quarrying industry is consumed in the comminution and sizing process. In most cases aggregate processing plants operate with minimum control features resulting in limited operational efficiency. Improved control is required to increase operational efficiency with concomitant savings associated with reduction in re-circulating load and improved resource utilisation. Development work has suggested that a combination of adaptive control and process condition monitoring could improve control of comminution plants. Many commercial process control and condition monitoring systems are available, but none were deemed suitable due to the domain specific characteristics of the application. An assessment of the particular characteristics of cone crushing concluded that the application was best suited to the use of small domain specific process control combined with bespoke condition monitoring. The processing power of the control system for the project is a function not of the academic requirement, but rather the economic and practical constraints imposed by the application. As a result of the constraints a high-end PC system has been designed in preference to a workstation. Within the research project work packages are sub-divided into novel wear sensor development, knowledge based control/condition monitoring and the investigation and mathematical modelling of the wear mechanisms inherent in cone crushing. Numerous strategies were considered to implement the control system outlined. The system currently under development is a modular design which utilises intelligent novel sensors to provide a variety of data inputs

Apr 1, 1994

By P. A. Davies

Paper presented at the conference: Risk assessment in the extractive industries, held in Exeter, UK, 23-24 March 1994, and first published London: IMM, 1994, preprint volume, 11pp., 15 refs. Hazards such as vibration, dust emission and fragment projection can result in an area called the Danger Zone being set around a blasting site. Traditionally Danger Zones have been set solely on the basis of consequences (e.g. based on the maximum distance of rock projection or expected ground vibration plus a defined safety margin). Advances in risk assessment and its growing acceptance as a safety management tool have led to the setting of Danger Zones based on both consequences and frequency of occurrence. This allows distances to be optimised on the basis of acceptable risk levels rather than the potential consequences of infrequent events. The setting of a flyrock Danger Zone is used to demonstrate a risk-based approach compared with a traditional consequence approach

Aug 1, 1995

The reduction of zinc from slags by a molten, carbon-saturated bath was examined in a laboratory study under conditions of continuous slag feeding. The results show that it is possible to reduce the bulk of the zinc from the slag before there is a net reduction of iron. However, the recovery of zinc was not as high as in batch tests performed in an earlier study. Lead in the slag was reduced simultaneously with the zinc to very low levels and was volatilised. Copper in the slag was reduced and dissolved in the alloy. An attempt was made to identify potentially commercial ways of treating zinc slags using an iron bath. The approaches that appear to have the greatest potential are reduction in a batch process using electrical heating and reduction in a continuous process with co- or countercurrent flow of the slag and alloy. In the latter the alloy would be prepared in a separate furnace before being contacted with the slag. The purpose of this would be to superheat and carburise the alloy so that no additional heat or reductant would have to be supplied in the slag-alloy reactor

Jul 1, 1991