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By R. D. Stewart

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, 18pp., 5 refs. A seismic risk assessment method has been developed for application to rockburst prone deep-level mining sites which have sufficient seismic coverage. The technique utilises several seismic hazard parameters simultaneously and assesses the seismic risk on a daily basis according to the individual levels of these parameters. Critical levels are determined from investigation of the long-term behaviour of the parameters in relation to recorded potentially damaging seismic events. The method has been applied to a data set comprising 15 months' worth of seismic data, with encouraging results

Aug 1, 1995

By Ruddle R. W.

Solid mattes are generally held to be either (a) eutectiferous mixtures of the component sulphides Cu2S and FeS or (b) mixtures of complex sulphides. This chapter shows that liquid mattes consist essentially of a homogeneous phase in which iron, copper and sulphur are present. The amount of sulphur is generally less than that required to account for all the metals as stoichiometric sulphides; mattes cannot therefore be regarded as mixtures of FeS and Cu2S. Some iron oxide may be dissolved in the sulphide phase and magnetite is often present as a second phase. If the sulphur content of the matte is reduced the composition enters the miscibility gap in the ternary system and either an iron- or copper-rich solution (depending upon the composition of the matte) separates as a new phase. On solidification any one of four phases (iron, copper, Cu2S and FeS solid solutions) may crystallize as primaries. The remainder of the matte solidifies as a ternary eutectic. It is possible that iron oxides enter into this eutectic. Knowledge of the ternary Cu-Fe-S system is far from complete and nothing is known of the quaternary system Cu-Fe-S-O

Jan 1, 1953

By B. J. Breen, C. S. Mogg

Considerable borehole investigation work has been completed at a proposed site at Sellafield in Cumbria, supplemented by seismic surveys, other geophysical sensing and geological mapping. The focussing of investigation on the rock mass itself will be achieved by means of the planned underground rock characterisation facility, giving access to depths of about 800 m in the strong, low-permeability basement rocks of the Borrowdale Volcanic Group. Characterisation work undertaken during the sinking phase and interaction with continuing surface-based exploration and monitoring should permit a firmer assessment of the long-term safety of a repository. Key considerations in the choice of a design for the repository include the waste handling method, underground inlet cell, underground vaults, vault environment and environmental effects

Aug 1, 1994

By D. W. Taylor, I. W. Farmer, N. Mojtabai

Rittinger's and Bond's descriptions of rock crushing relate the energy input required to fracture rock and the surface energy required to form new fractures to the change in specific surface area of feed and product during comminution. The potential applicability of this approach to blasting is illustrated, using the results of data from bench blasting tests on Pinal schists and production blasting of Carboniferous limestones. The approach contributes to understanding of the mechanisms involved in blasting and to the design of test blasts. A modified form is presented of the relationship between blasting energy, specific surface area of the muckpile and a rock energy constant related to the discontinuity structure of the rock. The modified equation fits observed data and offers a simple basis for further experiments

Jun 19, 1905

By Fearnsides W. G.

The second part of the paper, presented at the Midland Institute of Mining, Civil and Mechanical Engineers' general meeting held in Doncaster on 27th May 1916, addresses the post-Carboniferous and pre-Permian movements which brought about the partition of the area and gave to the North Midland district its individuality as a separate coalfield. As earth-movements of several ages subsequent to the Carboniferous have played a part in the formation of this particular coalfield, the aim is to elucidate the effects which belong to the post-Carboniferous and pre-Permian Period and to disentangle them from those of later date. This is done by comparing the geometry of the folded surface of one of the more important horizons in the Coal-Measures with that of the surface of unconformity which divides the Permian from the Carboniferous rocks in South Yorkshire, Derbyshire, and Nottinghamshire

Dec 1, 1916

By D. V. Venugopal, W. W. Gardiner

Spessartine-quartz rocks are manganiferous sedimentary rocks rich in spessartine and quartz which occur in north-central New Brunswick. They represent a recrystallised manganiferous siltstone/chert that is contained in or associated with red manganiferous siltstone (RMS) units. The spessartine-quartz rocks and RMS form part of an Ordovician volcanic and sedimentary succession within the Appalachian-Caledonian orogen which hosts numerous massive sulphides and polymetallic vein deposits. The New Brunswick spessartine-quartz rocks are spatially and temporally associated with stratiform base-metal, precious metal and hydrothermal tin-tungsten deposits. This suggests that spessartine-bearing lithologies and zones can be useful in predictive metallogeny and for the understanding of the stratigraphy and palaeographic setting of the early Palaeozoic rocks of the Appalachian-Caledonian orogen.

Jan 12, 1992

By S. L. R. Lenharo, H. Kahn, H. Born

Different ore types result from the irregular spatial distribution of the associated alkaline/carbonatite rocks and the zoned alteration profile within which apatite may have undergone reprecipitation. Different flotation responses are caused by their mineralogy, iron oxide impregnation and grain-size characteristics. Samples from seven deposits were crushed, screened and separated before being studied by chemical analysis, optical microscopy, X-ray diffraction, FTIR spectroscopy, cathodoluminescence and scanning electron microscopy. Two main apatite varieties with peculiar crystal morphology were identified: hydroxy-fluorapatite as the primary phase and carbonate-fluorapatite as the reprecipitated phase. The former occurs as prismatic or ovoid grains and the latter as polycrystalline aggregates or crusts on the primary grains; both are associated with iron oxide coatings (primary) or intergrowths (secondary). Microflotation tests showed variations in flotability for particular apatite associations as well as intensity of iron oxide coatings. The differences in flotation behaviour can be related to morphological properties and chemical substitution in the apatite structure

Aug 1, 1996

By L. B. Clarke

The optimal maintenance and control of the air flow and pressure distribution in a mine network are achieved by the correct positioning of the mine fans and regulators within the mine ventilation circuit. The principal considerations are the location of the main and underground fans or regulators and the attendant control of mine leakage. Air flow control is achieved by either passive or active regulation. Passive regulation adds resistance, usually in the form of a regulating door. Active regulation adds pressure sources in the form of underground booster fans. Ventilation engineers are increasingly turning to analytical tools to assist them in the design and operation of ventilation systems. The application of computer methods, formal optimisation methods and numerical solution methods is outlined

Jul 1, 1996

By S a m u e l D e a n

The author's written response to previous discussion was presented at the North of England Institute of Mining and Mechanical Engineers general meeting held in Newcastle-upon-Tyne, 8 April 1916, followed by further comments by Hare S. in support of his view that the conditions in English mines were the reason for less satisfactory results being obtained with heading machines and brief comments by Greener T.Y., President

Dec 1, 1916

By R. B. Scott, J. Hewitson

The paper investigates the historical information relating to spontaneous heatings which have occurred within the area from 1955 to date. From this information the seams most liable are identified and the location within the workings is enumerated, together with the possible reason for the occurrence of the heatings. Details are given of the precautions taken during development, working and withdrawal. Sampling procedures are outlined and the interpretation of the results is discussed. Reference is made to the various types of material and techniques employed in both preventing and combating heatings and examples are given of their relative cost and the operational experience obtained. Special observations are made on the changes in mining techniques and their influence on spontaneous combustion.

May 23, 1905

By T. Yalcin

In the Box-Wilson method, the correlation between dependent and independent variables is represented by a polynomial response function, whose constant and coefficients are determined by applying regression analysis to the experimental data collected. The five levels used for each variable consist of a minimum, a maximum and three intermediate values. A study was carried out using Ni-Cu ore from Sudbury, Ontario, in which 15 experiments designed according to the Box-Wilson method were carried out in random order and in duplicate. The two sets of replicate data showed close similarity, with an overall variance of 0.311 for the five parameters studied. The response functions were used to optimise frother dosage, collector concentration and air flow rate and an experiment was then carried out under the optimised conditions; the results agreed closely with those predicted by the response functions

Jun 21, 1905

By L. G. Billington

"The Agnew nickel deposit occurs in a major linear greenstone belt in the Archaean Eastern Goldfields Province of Western Australia, and has been subjected to mid-amphibolite facies nietamorphism of dynamic style. The largest dunitic ultramafic body in the Perseverance Block is host to the bulk of the nickel mineralization. The Perseverance Ultramafic is mineralogically zoned and has an embayed western margin against a mixed metasedimentarv-metavolcanic wallrock sequence.Three categories of nickel sulphide mineralization are concentrated on this western margin at the thickest part of the ultramafic exposure. Massive sulphides characteristically occur as contact mineralization, internal mineralization and as remobilized concentrations in vein form structures. Disseminated ore constitutes the largest volume of mineralized materials in the deposit and occurs in three separate shoots in en-echelon relation. Weakly mineralized 'cloud sulphide' zones surround and envelop the shoots and persist much further along strike. In the upper mine levels the shoots are truncated by a shear or crush zone, which inhibits geological knowledge to the south but marks a major fundamental structural break.Most of the ore types have suffered supergene alteration and there is a complex variable distribution of the mineralogical facies. The ore types have been metamorphically retextured, but the oreshoots can be characterized by their Ni tenor and some chemical ratios. S/Se values, PGF. and precious metal values are distinctly different from those of other nickel sulphide ores extracted.Despite intense structural and metamorphic modification of the mineralizations, some features support an original magmatic derivation for the sulphides. These include the localization of massive sulphide ore types on one marginal contact within an emhayment structure, the general distribution of disseminated mineralizations located immediately above the massive sulphides and the Ni/Cu, Ni/Co, Fe/Ni ratios of the oreshoots being similar to those of deposits that typify the intrusive dunite- associated class of nickel sulphide deposit. Varying S/Ni ratios between different shoots suggest a revision of the single magmatic intrusion model in favour of a changing composition between successive magmatic episodes."

Jan 1, 1984

By B. Denby

Paper presented at a meeting on: Artificial intelligence in the minerals sector, held in Nottingham, UK, 20 April 1993. The design and scheduling of open pit operations are consistent problems encountered by the surface mining industry. Numerous techniques and algorithms have been developed to assist the mining engineer in the creation of optimum development strategies. Virtually all the practical techniques that have been produced have concentrated on one of the aspects (limit definition or scheduling) at the expense of the other. It has long been recognised, however, that the two activities are intrinsically linked and thus solving either problem independently of the other can only ever produce sub-optimal results as a whole. This has been termed the "circular reasoning problem". It has also been recognised that, for all practical-sized situations, solving both problems simultaneously is virtually impossible using conventional techniques due to the massive size of the search space involved. A technique is presented which is based on a self-learning genetic algorithm, which provides a combined pit limit and extraction schedule simultaneously in order to maximise the NPV (net present value) of the extraction. The theory is developed in two-dimensions and a number of examples of its application are presented. It is proposed that this approach is a highly efficient, heuristic technique offering the potential to transcend the circular reasoning difficulties of separate pit limit and extraction scheduling systems. Extension of the technique into three-dimensions and its application to realistic problem sizes are discussed

Apr 1, 1994

By J. Ostwald, L. T. Matthews, C. E. Loo

Australia has large reserves of pisolitic limonite. Mining recently commenced on the Yandicoogina deposit to produce a high-grade sintering ore. The ore contains about 10 wt% combined water and simulated sintering temperature profiles indicate that progressive dehydration of ore particles occurs in the temperature range 300-700 degrees C. Studies by optical microscopy show that although the dehyrdrated ore particles contain numerous cracks, there is no change in the microstructure of the ore because topotactic transformation to haematite results in the formation of compact masses of very fine-grained haematite microcrysts. When the ore is held at around 1 200 degrees C for 1 min significant recrystallisation of these microcrysts occurs, resulting in the formation of optically visible, micrometre sized haematite crystallites. Studies to simulate the behaviour of ore particles during sintering (as nuclear particles surrounded by a standard adhering fines mixture) show that the recrystallisation process occurs much earlier at temperatures of about 900 degrees C. Further studies indicate that CaO in the adhering fines mixture enhances the recrystallisation of the ore nuclei. The results of the investigation indicate that the pseudo-relict haematite in sinters produced from ore blends that contain significant levels of pisolitic limonite consists of dehydrated goethite that has undergone significant recrystallisation and grain growth, a phenomenon that is facilitated by the presence of lime derived from the sintering melt.

Jan 12, 1992

By C. McCall, J. T. Knight, J. R. Ridley

Gold mineralisation in the gabbro sills is mainly stratabound to quartz- and Fe-rich, granophyric-textured units and is sited in undeformed, brittle quartz vein sets, which form pipe-like orebodies. Hydrothermal wallrock alteration consists of hornblende-plagioclase-calcite-quartz with minor biotite, garnet and chlorite and with arsenopyrite and pyrrhotite as the dominant sulphides. Geothermobarometric data suggest that gold was deposited at around 520 degrees C at 2.8-3.8 bar. Mineralisation is thought to have occurred during amphibolite-facies metamorphism. Fluid inclusion and isotope data indicate that gold mineralisation was the result of deposition from a low-salinity H2O-CO2-CH4 fluid of either metamorphic or magmatic origin. Although the Three Mile Hill deposit differs from others in the area in its wallrock-alteration assemblages, peak-metamorphic timing of gold deposition and distinct geochemical associations it forms a brittle stratabound ore body which suggests structural and gold-depositional mechanisms in common with those of the other gabbro-hosted gold deposits

Jun 18, 1905

By P. J. Rowsell, M. D. Waller

Paper presented at a meeting on: Artificial intelligence in the minerals sector, held in Nottingham, UK, 20 April 1993. The applications of artificial intelligence systems in the upstream petroleum industry are reviewed. Particular emphasis is placed on current and potential applications in drilling engineering. Several recent advances in drilling technology have led to a large increase in the quality and volume of data available. This combined with the escalating cost, particularly of off-shore operations, is testing the traditional reliance on the skill and judgement of rig operators. AI systems offer enormous scope in enhancing and aiding the performance of these operations

Apr 1, 1994

By G. Richards

Research shows that having more women in the top mining jobs can bring bottom-line benefits. Mining companies are starting to embrace the need for greater gender diversity at board and senior management levels, figures and examples are given.

Jul 1, 2015

By D. C. Kaliampakos, A. K. Moutsatsou, J. K. Skotaras

The wastes from marble extraction in the Thasos- Kavalla-Drama region of northeastern Greece could be utilised as a new source of high-quality white carbonate fillers for the European market. Large deposits, satisfactory properties, acceptable processing costs and environmental benefits are among the factors that would have a positive bearing on a proposal for their use in this way. DTH, the waste arising from dolomitic marble quarrying operations on the island of Thasos, appears to be the more suitable material than DA waste from Nikissiani on the mainland because of the lower cost of primary grinding and the higher production rate of ultrafines with a mean particle size of 5 micrometres (the optimum size for filler properties in the case of both DTH and DA), its superior whiteness, the benefits that such use would bring to a very severe and complex environmental problem and the lower transport cost

Jun 18, 1905

By M. T. Styles, E. Condliffe, R. C. Leake, R. J. Chapman, D. J. Bland

Paper presented at Mineralisation in the Caledonides, the Mike Gallagher memorial meeting held in Edinburgh, 27-28 June 1996. Quantitative point analysis and microchemical mapping identified 52 different types of mineral in inclusions, usually ranging in size from 5 to less than 1 micrometre, inherited from source bedrock. A combination of grain chemistry, heterogeneity and inclusions provides a grain signature reflecting the type and history of source mineralisation. Several grains from an alluvial site are needed, to allow for bedrock variation and the presence of inclusions in only 10-20% of grains. A total of 1 530 grains obtained from 30 localities in Scotland were of ten types, two of them minor variants. Two types in the Highlands may be related to centres of Caledonian igneous activity, but the most widespread is likely to have been of deep-seated origin and structurally controlled. Gold in the Ochil Hills is probably from a source associated with Devonian andesitic activity. In the Southern Uplands, grain types reflect two separate episodes of mesothermal lode gold mineralisation and relationships with Permian red beds/mafic volcanics and with Tertiary dykes

Jun 19, 1905

During the construction of storage caverns, and during their lifetime if the use to which they are put so requires, it is necessary to provide adequate ventilation to ensure the safety and comfort of the underground workforce. An analysis of likely contaminants during construction has indicated that where a large facility is situated in a rock mass of even moderate temperature climatic conditions are likely to be the limiting factor during most of the mining operation and atmospheric pollution when blasting is undertaken. Possible options for improvement are increased air flow, cooling of intake air and reduction of the heat source by altering the number and type of haulage units employed in the cavern. Local solutions are an alternative approach where heat problems are confined to a few specific locations

Aug 1, 1994