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Discussion at the North of England Institute of Mining and Mechanical Engineers' general meeting held in Newcastle-upon-Tyne, 8th April 1916, on the paper published in Trans. I.Min.E., vol.LI, 1916, p.72-90, included written contributions on size and gauge standardisation by Lupton A., Peck W.R., Dean S., Mayer R.W. and Ashworth J., with the author's written response, and by Bulman H.F. and Brown M.

Dec 1, 1916

By R. Winand, P. Harlet

he cathodes produced are of electrorefined grade; metallographic structure and surface roughness are controlled to a depth of 1.3 cm (single-side deposits); silver levels in the cathode are regulated by the presence in solution of Cl- and Br- ions; organics must be used at very low concentrations (around 0.1 mg/l with a consumption of about 0.01 mg/l/hr). The required concentrations of additives were established according to a well-defined strategy based on the consumption of organics at the cathode by a mass transfer limited-process.

Jan 4, 1992

By R. J. Howarth, P. L. Llowenstein

The errors resulting from field sampling, sample preparation and analysis are investigated for drainage sediments derived from homogeneous sandstone, shale, limestone, basic igneous and granite lithologies as a background to a primary reconnaissance survey of England and Wales. Emission spectrographic analyses of approximately 350 samples for Al, Ca, Fe, K, Si, Ba, Co, Cr, Cu, Ga, Li, Mn, Ni, Pb, Sc, Sn, Sr and V and atomic absorption analyses for Cu, Ni, Mn, Co, Zn and Pb have been treated statistically. For routine broad-scale surveys analysis of the unground -80-mesh sediment fraction proves satisfactory. Sampling error between localities in a stream is shown to be less than spectrographic analytical error for many of the elements considered here, except where mineralisation (contamination) occurs, but exceeds the atomic absorption analytical errors in most cases. Unless it it critical to reduce the amount of between-site variability (having regard to analytical errors) in the regional survey, there appears to be no advantage in the use of a more sophisticated sampling technique. The utility of moving-average maps in reducing the width of the confidence belt around the regional 'geochemical surface', and thus compensating to some extent for the sampling errors, is also demonstrated.

Dec 1, 1971

By Y. L. Ding, N. A. Warner

Cylindrical pellets made from graphite and chromite mixtures were reduced in high-carbon ferrochromium melts at 1 600-1 695 degrees C, under an atmosphere of almost pure CO. The reduction rate, as measured by gas evolution, increased with increasing melt temperature and graphite addition and with decreasing pellet diameter or height, although reductant particle size had a very limited effect on kinetics. At a pellet size, heat and mass transfer were significant in controlling the early stages of reduction of large pellets while at chromite grain size, gas diffusion was probably a rate-controlling step. The time required for dissolution of unfluxed pellets into the melts was significantly longer than that for reduction. This indicates that pellet dissolution may be the limiting factor in determining the operating parameters for a proposed new process to produce high-carbon ferrochromium using melt circulation

Jun 19, 1905

By J. M. Smith

This resume provides an account of the work of the Bureau and it's establishment by an Act of Parliament in August 1916. The Medical Bureau is concerned solely with the administration of the medical provisions of the Act. Its main functions are to conduct and to direct or control the medical examinations provided for in the Act. The paper covers the changes in type of silicosis, classification into the three legal stages of silicosis, cancer of the lung and tuberculosis.

Jan 1, 1947

By Tawsaporn Nuchanong, Ian Nichol

Investigations of the dispersion of gold in soils and stream sediments associated with three gold deposits in Thailand indicate the existence of different geochemical dispersion patterns in the three areas, demonstrating the need for the adoption of a variety of exploration techniques. The three gold deposits which were investigated were the Phu Tham Phra-Phu Thong Daeng copper-gold prospect, the Doi Tung and the Huai Hin Lab gold prospects. Overall the investigations at the three localities demonstrate clearly that the chances of exploration success can be significantly enhanced if composite soil samples are analysed to ensure a more reliable estimation of the gold content in soils and if both the 63 micrometre fraction and the field-panned concentrates of stream sediments are analysed because of the variable grain size of the gold characterising different gold deposits and surface environments.

Jan 4, 1992

By R. W. Ruddle

The advent of new methods of roasting, “flash roasting and fluidisation”, which are now under development, combined with the use of oxygen-enriched air, may markedly increase the SO2 content of roaster smokes. Skogmo suggests that the production of smokes containing as much as 50 per cent SO2 should be feasible. The use of flash smelting processes may well enable a similar increase in the SO2 content of smelter smokes to be made. In this event the recovery of sulphur would be greatly cheapened and the process might well be much more economic, even if allowance is made for the cost of generating the oxygen

Jan 1, 1953

By A. Paulin, A. W. D. Hills

The work has shown that packed-bed behaviour can be predicted from the results of single-particle experiments, total reaction times being predicted somewhat more accurately than gas and solid temperatures and gas compositions. A small laboratory packed-bed reactor was built and used to study the decomposition of beds of specially prepared CaCO3 spheres, steps being taken to minimise the effects exerted by the walls of the bed on processes occurring within the bed. Gas and solid temperatures and gas compositions were measured at various points in the bed and compared with theoretical predictions based on kinetic data determined in previous single-particle experiments. The measured solid temperatures and total reaction times agreed remarkably well with the values predicted theoretically. Gas and solid temperatures measured after the reaction had finished at any point in the bed did not agree with the theory. This was because solid temperatures in the bed rose very rapidly once the reaction was completed and the walls of the bed could not be heated at a sufficient rate for their temperatures to rise as rapidly; thus some loss of heat from the bed to the walls was inevitable, and this could not be accounted for in the theory. In addition, the theory did not allow for the conduction of heat within the bed, and this resulted in some further slight discrepancy between the measured and predicted values, particularly after the reaction was completed. Gas compositions measured in the bed were rather scattered, but, even so, they agreed moderately well with the predictions of the theory.

Dec 1, 1971

By J R. Leeming

The paper describes a technique that has been developed by the Health and Safety Executive (USE) to make an assessment of the effectiveness of Health and Safety (H and S) management at complex sites. The paper then describes how the technique was adapted and used for the first time at a large coal mine. The results highlighted certain deficiencies in the safety management system, allowing directed advice to he given to management.

Jan 4, 1997

By I. A. Scott, T. J. Napier-Munn

Size-by-size partition curves for mineral separation in dense-medium cyclones pivot about a single characteristic point. This is defined for stable, non-segregating media by the medium density and the proportion of the medium reporting to the underflow. The pivot point departs from these values for unstable, conventional media. The phenomenon can be represented by an equation with two parameters defining pivot point coordinates and two the Ep value. On the basis of experiments in a 200 mm cyclone using ferrosilicon media, simple regression equations were developed for the separation parameters in terms of operating conditions (the coefficients were likely to be site-specific). The experiments successfully decoupled the effects of medium density and viscosity and showed that the value of Ep was independent of the former but strongly dependent on the latter. A classification model was used to predict the density of the underflow medium, a knowledge of which is required to determine the pivot parameters. The model correctly reflects the performance trends observed in dense-medium cyclone operation and has the potential to be generalised to a wide range of industrial practice.

Jan 8, 1992

By I. R. Hanby

A simple but comprehensive method has been developed for the simulation of a mechanical-drive dump truck that enables various parameters to be predicted as a function of time throughout its whole cycle. Uses of the simulation results are indicated with specific attention to environmental and operational or economic planning. The output of a sample run is presented. The method can be easily adapted for the investigation of a wide variety of mobile plants.

Jan 4, 1992

By F. Reich, S. L. Chryssoulis, K. G. Stowe

The surface chemistry of particulates from mineral processing streams can be determined by laser-probe microanalysis. The small area of analysis (2-30 micrometres) enables the surfaces of individual grains to be characterised. Conclusions are based on data acquired from a statistically significant number of grains of a given type. Maps showing the distribution of elements on the surface of mineral particulates can be obtained by time-of-flight secondary ion mass spectrometry. The importance of such analyses in understanding the response of minerals to beneficiation practices is discussed with reference to three examples. The first relates to the loss of selectivity in the differential flotation of a base-metal ore, the second to the different flotabilities of coarse- and fine-grained pentlandite from a Cu-Ni ore and the third concerns the preg-robbing effects of organic matter in a carbonaceous gold ore.

Jan 4, 1992

By E. J. Bolitho

"The paper covers the activities of the Government Miners' Training-Schools. It argues that its success is proved by the steady demand for miners trained at the Schools; by the large numbers of ex-apprentices who hold responsible official positions in the industry; and bv the probable expansion of the organization in the near future to meet the never-ending call for trained personnel."

Jan 1, 1947

By A. H. G. Mitchell

Gold-poor and gold-rich porphyry and epithermal gold-silver deposits of Caenozoic and Cretaceous age in the western Pacific and central and eastern Europe are confined to predominantly andesitic continental margins and island arcs. The arc volcanic rocks overlie a complex non-oceanic basement of stacked nappes, the uppermost of which is often ophiolitic. The emplacement of ophiolite triggered a reversal of tectonic polarity, subduction and arc magmatism. Andesitic volcanism and the formation of a strato-volcano were followed by the ascent of magma and porphyry copper mineralisation. Regional propylitic alteration came from convecting, predominantly meteoric fluids. Magmatic degassing caused advanced argillic alteration. This is commonly unmineralised in perched water tables, but may sometimes host high sulphidation gold or enargite gold at deeper levels within the propylitic zone. The onset of extensional stress after the andesitic volcanism allowed meteoric water to circulate to depths of 5 km or more, with consequent cooling of an ascending magma body at depth and the development of low sulphidation epithermal gold mineralisation near and immediately above the sub-volcanic basement surface. All andesitic arcs are mineralised. Regional controls on their ore potential include the level of erosion and geological features in the basement that focus the ascent of fluids. Differences between the mineralisation of the European and the western Pacific arcs may reflect the presence of older, more granitic basements in many of the European arcs.

Jan 12, 1992

By Ruddle R. W.

Magnetite occurs in the reverberatory furnaces, blast furnace and converter (a) as the result of its presence in the materials charged, and (b) as the result of oxidation of the FeS in the charge in the absence of sufficient SiO2 to slag the FeO as it is produced and thus prevent its subsequent further oxidation. Magnetite is reduced by FeS according to FeS+3Fe3O4=10FeO+SO2 and similar reactions. This reaction is markedly affected by temperature and does not proceed to any important extent below about 1200°C. To ensure comparative freedom from magnetite it is therefore necessary to raise the temperature of the furnace to the highest practicable figure and to use plenty of siliceous flux. Since the maximum operating temperature is likely to be limited by the resistance of the refractories to attack by the slag, investigation of the factors affecting this attack should be helpful. It is reasonable to suppose that the formation of magnetite might be minimized by ensuring intimate admixture of matte and slag during conversion so that silica is readily available for combination with ferrous oxide as the latter is formed. The literature gives no clue to the importance of this factor and some experimental work on this aspect might be fruitful

Jan 1, 1953

By R. G. Siddall, W. Gale

In the UK the development of the science of strata control has been strengthened by a resurgence of interest in the specialism of roofbolting and its associated techniques. The evolution of the theories and practices of strata bolting in roadway stabilisation is discussed. Practical experiences are considered, principally the use of Australian techniques, the relationship between bond strength and annulus and the effects of stress in the ground. Areas of new technology such as cable bolting, injection anchors and on-board bolters are also discussed. The recent advances in computer technology and rock testing equipment and methods have provided the opportunity to simulate ground behaviour under various conditions. Computer modelling developments and the use of techniques to predict ground behaviour are described.

Jan 4, 1992

By Haldane J. S.

(Paper presented at the Institution of Mining Engineers' general meeting held in London on 8th June 1916.) It was shown in the last Supplement to the Registrar-General's Reports, in connection with the census of 1901, that the general death-rate among colliers was considerably lower than in the great majority of occupations but that there is an exception to this in the case of colliers above the age of 55. Examination of the statistics finds that the excessive death-rate among old colliers is to a large extent only apparent, and that the real excess of bronchitis from which they have suffered has greatly diminished. It is concluded: (1) that good ventilation is of considerable importance to the health and continued working efficiency of miners, as well as to their safety from accidents; and (2) that there is no real statistical evidence of harm resulting from the inhalation of coal-dust or shale-dust in the quantities ordinarily breathed by miners, and a strong presumption that the dust they breathe protects them against serious dangers from bacilli that are removed from the lungs by the dust-clearing cell mechanisms

Dec 1, 1916

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 L. T. Matthews, C. E. Loo

During sintering, porous ore particles are easily assimilated by liquid melt. Two simple models of the process are considered: the dissolution of a solid by a liquid and the penetration of a liquid into a porous solid. Laboratory sintering studies covering a range of experimental conditions were undertaken to characterise the assimilation of large particles of ore and flux by melts formed from different mixes of fines. For ores, the process appeared to be complicated by the detachment of fines from the ore surface prior to melt formation, according to the mass of adhering fines and surface roughness of the particle. This delayed the onset of assimilation and sometimes reduced it, although melt penetration was fast and effective. Studies using different temperature profiles suggested that the assimilation of haematite was controlled by the transport of Fe2O3 away from the surface of ore particles. The assimilation of limestone depended more on thermal conditions than on the three magnesia-bearing minerals considered. Changing the composition of the initial melt significantly altered the extent of assimilation of ores and limestone, but again had a less marked effect on the magnesia-bearing fluxes.

Jan 8, 1992

By J. Cech

Discussion is presented of a decision-making support method for the spacing of ore passes along a long vein orebody and the division of the orebody into convenient stopes for future mining operations. The method was tested on a Slovak siderite deposit and also on some hypothetical cases with the objective of obtaining more general results

Jun 18, 1905