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By H. L. Willett

Wrapping up the symposium, covers incidence of spontaneous combustion in British mines, assessment of liability to spontaneous combustion, precautions, rate of advance, starting a line of a coalface, local heatings at roadsides, burying packs, coal headings, retreating longwall, detection and sealant coatings.

May 23, 1905

The following procedure was used to determine cut-off grades: define the orebody profile; plan the stope layout and quantify the work involved; formulate equipment-performance norms; calculate unit costs; input process recoveries and metal prices; and calculate the cut-off grade. Use of the method is illustrated using data from a copper mining complex in India. Results from the study led to the following conclusions for underground mines in general. Cut-off dependent costs vary significantly with the stoping method employed, orebody thickness, the degree of mechanisation and the working efficiencies of the workforce and equipment. This applies even within the same deposit. Sub-level stoping and its variants can be operated at a lower cut-off grade than cut-and-fill and its variants. Thinner orebodies affect cut-off grades adversely, but with thinner orebodies very little further reduction in cut-off grade can be achieved once a certain minimum width has been exceeded. For the same stoping method and in the same mine the cut-off grade varies with the degree of mechanisation. Labour-intensive methods require higher cut-off grades. An allowance for working efficiency should be made when calculating cut-off grades. Higher process recoveries allow a significant lowering of cut-off grades

Jul 1, 1996

By S K. Das

An intensive investigation into modern roof support technology, including hy draulic and control systems, has been carried out against the perspective of global development and support behaviour on longwall faces across the Indian sub-continent. The wide ranging study examined various types and designs of modern supports used in seams of varying thickness and inclination where caving and stowing were practised. Consideration has been given to structural analysis, support resistance, the various forces acting over and on the powered supports and to support compatibility. The examination of the phy sical parameters has been allied to field experience and, together, have led to the formulation of standard designs for both the powered support structure and structural systems. A realistic mathematical model has been formulated for calculating the capacity of roof support requirements resulting from the actual behaviour of the immediate roof stratum. As a result of the work, it should be possible to readily select the most appropriate type of support sy stem for the conditions and longwall mining method that is to be employed.

Jan 4, 1997

By J. S. WARWICK, E. J. Browning

Ignitions continue to occur underground, sometimes leading to major explosions. There has been considerable effort in the UK, and more widely in the European Community, to formulate the best ventilation practices and other means of minimising these incidents. Practices and procedures to prevent ignitions are discussed in the light of the risks from current mining methods.

Jan 1, 1993

By G. P. . RiddIer

The ninth symposium in the series 'Prospecting in areas of glaciated terrain' was organized by the Institution of Mining and Metallurgy in association with the British Geological Survey and was held in Edinburgh from 2 to 4 September, 1991. Dicussions of sessions are presented.

Jan 4, 1992

By D. J. Buchanan

British Coal's mining research programme is directed towards the strategic objectives of reducing production costs, improving product quality and resolving health, safety and environmental issues. The strategy for R&D is described and selected parts of the programme are reviewed. Two major initiatives are directed towards reducing production costs: geotechnics and automation. Integrated exploration techniques are used to delineate geological structures as an aid to mine planning. Rockbolting is being rapidly introduced and the in situ stress field has been found to be of significant influence. Automation is the subject of a major programme. A strategy for coal quality has been devised. The health, safety and environmental programme concentrates on the traditional hazards together with surface environmental problems.

Jan 12, 1992

Discussion of papers with authors' written replies and closing remarks.

Jan 1, 1947

By B. W. Hester

Report of discussion at January, 1971, general meeting (Chairman: M. J. Cahalan, President) of the paper published in Transactions/Section B (Applied Earth Science), vol. 79, May, 1970, pp. B60-B67, and contributed remarks. Comments were made by Taylor J.T.M., James C.H., Lethbridge R.F. and Heath K.C.G.

Dec 1, 1971

By A. Z. Lang, D. A. Hall

After a brief description of the causes of spontaneous heating and of general preventative methods, a detailed account is given of occurrences of spontaneous heating in the Main Seam (locally known as the 5/4 Seam) at Westoe Colliery. This seam is about 12 feet thick consisting of hands of coal and shale, but only 4 feet 6 inches is worked because of the thickness os strata in water-bearing rocks and the worked section is selected on quality considerations. An advancing longwall face in this seam (2nd South) began to heat after working for six months and ultimately had to be abandoned. By adopting retreating methods and mining narrow panels it has been possible to extract this coal at an excellent rate of productivity. The system of goaf ventilation is important, because the use of a bleed road would have given rise to dangerous conditions in a goaf which of necessity would have contained fallen coal. Preparatory seals were prepared at selected sites so that, if necessary, a panel could be sealed off quickly; these seals are completed as soon as possible (within three weeks) of finishing a panel. A gas sampling system has been instituted which includes daily sampling on the face and in the goaf, and weekly sampling at the stoppings of all completed panels. The coal has now been extracted from this seam for three years without any further difficulties from spontaneous heating.

May 23, 1905

By Mowat D. M., Louis H., Smith W. Mackey W. M., Dron R. W., Ellison C. C., Winmill T. F., Kerr G. L., Haldane J. S., Ashworth J., Garforth W., O'Shea L. T.

Discussion of Winmill's paper, including various anecdotal examples, is presented together with the author's response; topics included: the need to distinguish cubic pyrites from the rapidly decomposing rhombic form known as marcasite; the effects of moisture content in the coal and air; the possible effect of pressure; the heat insulation resulting from heap/stack size; and the means of determining pyrite and moisture contents

Dec 1, 1916

By T Atkinson, A Cobb, R AJIington

Risk management is concerned with the whole spectrum of financial, geological, engineering, legal, governmental, social and occasionally ethnic issues, concerned with mining projects. The inherent risks in mining operations are well publicised, but new issues and hazards arrive on the scene and lake precedence, but the older risks still remain, while insurance cover may not he ‘full cover’ in the future. It has long been recognised that quantitative approaches to risk analysis can play a major role, but although these methods are capable of considerable theoretical precision, the lack of sound risk input data and experienced personnel limits the usefulness of theoretical analysis. It can, however, greatly assist in comparing cases, in identifying areas of risk and help in the investment decision process. Its major contribution to a mining project is that it imposes an investigative discipline that also assists in improving the quantitative approach to risk analysis and hence risk management. Risk analysis and risk management also requires sound common sense and major inputs from experienced geologists, mining, mechanical, electrical and mineral processing engineers. The Engineering Council, in 1992, issued a ten point code of professional practice entitled ‘Engineers and Risk Issues’ (The Engineering Council. 1992), covering our professional responsibilities, the law, our conduct, the need for a systematic approach to risk issues, the use of professional judgement, communications, risk management, evaluation of risk, our professional development in this field and the encouragement of public awareness of risk issues. This is a specific area of training perhaps long neglected by our industry and academic institutions (Atkinson. 1983).

Jan 5, 1996

By Tuncel M. Yegulalp, Selamet G. Ergelebi

A description is given of a method of analysing modern mining systems in terms of reliability and their effects on productivity. Non-exponential distributions, such as the Weibull and lognormal distributions, for failure and equipment repair times are also considered. The resulting non-homogeneous Markov process is solved by the method of stages. A longwall mining system is analysed as an example.

Jan 4, 1993

By D. J. Wall, T. D. Johnson, M. T. Parry, G. R. Heath

In coal-fired power stations coal is ground to a fine powder and then transported pneumatically at 25-30 m/s velocity to remote burners. Wear of the conveying pipework is a well recognised problem and traditional lining materials are Nihard and basalt. In many cases these are being replaced by alumina tiles in order to improve life and reduce the frequency of replacement. A programme of laboratory testing of candidate aluminas with AIO, contents between 85% and 99-5% has been undertaken and the results compared with field experience. This gives confidence in the erosion tests, which were designed to replicate most of the field conditions. However, it has not proved possible to draw correlations between the laboratory erosion rates and any of the materials’ bulk properties. SEM, TEM and microanalysis studies have therefore been made in order to look for microstructural aspects that could be influencing erosion rates and it has been shown that intercrystalline cohesion, the matrix phase and porosity appear to have most influence on wear performance. It is necessary to quantify these microstructural parameters if reliable erosion performance is to be obtained. This paper was read at the Institute of Ceramics Annual Convention at the University of Durham, April 1988.

Jun 12, 1905

By Hirsch H. H.

The paper, presented at the North of England Institute of Mining Engineers' general meeting held in Newcastle-upon-Tyne on 12th February 1916, gives a short description of the Hirsch lamp, which, though largely used in the United States of America, has not yet been adopted in Great Britain. The lamps, which consist of (1) the watchman's lamp and (2) the miner's lamp, are portable, and have been designed to provide a safe and reliable light for use by watchmen, and in mines, rescue-work, powder-works, oil-refineries, and other places where special precautions become necessary on account of the presence of explosive materials or gases. The lamps are in each in­stance operated by a storage-battery contained within a casing, and this supplies the current necessary for a miniature incandescent lamp. Each safety-lamp forms a complete unit and can be carried from place to place or held in any position. Appendices give details of battery cleaning, test results and safety reports

Dec 1, 1916

By Gibson J.

Further discussion at the North of England Institute of Mining and Mechanical Engineers' general meeting held in Newcastle-upon-Tyne, 3rd June 1916, on the paper published in Trans. I.Min.E., vol.LI, 1916, p.72-84, included a written contribution by Parfitt I.C. and the author's written replies to this and previous discussion

Dec 1, 1916

By John Craw

This paper has formulated the methods, both medical and engineering, for the control of pneumokoniosis in the haematite-mining industry in West Cumberland, but this is only part of a general service to improve the lot of the worker in these mines, to make him a better and happier workman, and to permit him to enjoy his work and leisure in comfort and good health. This organization has now been functioning for more than ten years and the results are indeed heartening, but it is only as a result of constant vigilance from the mining and medical point of view that such a plan can operate efficiently. The human element and its full understanding is by no means the least of the problems.

Jan 1, 1947

By R. G. Jones

Many novel projects suffer delays, cost overruns or failure because of inadequately qualified technologies. A new qualification to measure the quality of innovation is discussed.

Jul 1, 2015

By S A. M Crawshaw, J A. B Fortune

Trackless battery powered haulage vehicles have been in operation in British coal mines principally for longwall face transfer and personnel transportation. Changes within the industry have resulted in the introduction of room and pillar coal mining methods and the introduction of increasingly heavier longwall roof supports This has resulted in the introduction of: • Battery powered coal haulage machines, which, without the need for trailing cables, increase productivity within room and pillar mining. • Battery powered longwall shield haulers which are capable of carry ing the heaviest shield supports currently being utilised within the British coal mining industry. The conventional machines have been adapted from an American design to meet the requirem ents of European legalisation. This has seen the- emphasis being placed upon the supplier with the European M achinery Directive being introduced, necessitating the assigning of a 'C E ' m ark to each vehicle. Battery vehicle technology has advanced to meet the demands of the ever changing market and will no doubt he further adapted to meet the requirement of the British coal mining industry.

Jan 10, 1996

By Walshe J. M.

The slow-speed compressor is giving place to the high-speed type, with its greater economy of material and space; and, where very large units are required, the turbo-compressor is supplying the need. In the very large air-supply stations on the Rand, turbocompressor units of a capacity of 20,000 and even 50,000 cubic feet, requiring 4,000 to 13,000 horsepower, are quite a commercial proposition, and have proved a practical success. Air-compressors of this size are, however, very exceptional, and the high-speed reciprocating compressor is quite capable of dealing with the highest outputs so far required in this country and, in the hands of manufacturers experienced in the design of high-speed steam-engines, a very high standard of reliability and efficiency in operation is obtained. The so-called “high-speed” or more correctly quick-revolution type of compressor is now extensively used in mines and collieries; for the air-pressures required for power purposes in mining work, two-stage compression, with an intercooler between stages, is the design usually adopted in best practice. It is not the writer’s intention to describe a variety of high-speed air-compressors but to select as an example of this type of compressor the one with which he is most familiar, and which is probably more largely used than any other, namely, the double-acting two-cylinder two-crank type with automatic light-plate air-valves, and with the working parts lubricated on the forced-lubrication principle. Sectional drawings, efficiency curves, air-cylinder diagrams and other data accompany the descriptions and photographs of compressor design, components and mine applications

Dec 1, 1916

By NA NA

Reports of discussion at sessions held in Keyworth, UK, on 22-23 April 1992.

Jan 12, 1992