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By T R. Meng, C Wu

After carrying out a brief review of the existing safety assessment criteria for the spontaneous detonation of explosives in the mining of sulphide ore deposits in China, and giving a detailed description of the dynamic process and mechanism of the spontaneous detonation of explosives and the relative factors, the latest research results of three kinds of explosives reacting with a group of sulphide ores are presented, based on a reliable experimental method. Afterwards, a complete safety criterion for spontaneous detonation assessment, which depends on the hole temperature, the water solution Fe2+ and Fe3+ and the pH value, is established to determine (he safe charging time of explosives in variable conditions. The criterion is verified as correct by a large-scale field test.

Jan 10, 1996

By M. J. Howes

The high degree of mechanisation, which is mainly diesel-powered, has a significant effect on heat loads; heat output from this source often exceeds the heat flow from the surrounding rock. The extensive use of diesel-powered equipment also influences ventilation rates and minimum values are necessary to ensure that emissions of diesel exhaust are adequately diluted. Many Australian mines are in subtropical or tropical areas with high ambient wet- and dry-bulb temperatures on surface. This, coupled with the large amount of heat from mechanisation, usually means that refrigeration is required at much shallower depths. A secondary problem is associated with the definition of acceptable thermal environment conditions, which are sometimes based on the assumption of no air movement. This gives rise to very stringent thermal environment acceptance criteria, which, in some areas, would prohibit work on surface, let alone underground

Jun 12, 1905

The report of the Annual General Meeting of the Institution of Mining and Metallurgy held on Thursday, 20 May, 1971, in the rooms of the Geological Society of London, Burlington House, Piccadilly, London, W.1, at 4 p.m. (Chairman : M. J. Cahalan, President) includes details of awards and prizes presented to William Justin Kroll, Sir Gordon Colvin Lindesay Clark, John Convey, Evert Hoek, Peter Reginald Dawson and Christopher Michael St. John

Dec 1, 1971

By Winmill T. F.

The previous papers have been concerned only with the atmospheric oxidation of coals from the Barnsley Seam, for which it has been shown that an adequate explanation of the origin and nature of gob-fires can be based on the reaction between the coal itself and the oxygen of the air without the intervention of any other substance. It becomes of importance, therefore, to ascertain how far a similar explanation will hold good for spontaneous heating in other seams, and with this object in view samples including anthracite and lignite have been taken from a considerable number of pits in different parts of the UK (south Wales, Northumberland and Durham, north Staffordshire, Portrush and Ayrshire), some liable to fire, others not. There is abundant evidence to support the commonly-accepted view that spontaneous heating is due to the heat evolved during the absorption of oxygen from the air by coal or pyrites. The quantity of heat produced by the reaction has been measured and it has been shown that the observed rate of heating of a sample of coal agrees with the rate calculated from the heat of reaction and the rate of absorption of oxygen

Dec 1, 1916

By B. D. Rayment, J. D. Wilson, G. R. Davis

Wheal Jane, situated between Truro and the Carnmenellis granite, is under development by Consolidated Gold Fields, Ltd., as a tin producer. The main or B lode comprises a complex cassiterite-sulphide ore located in shear zones along the footwall of the lowest of a series of porphyry dykes (elvans) which strike ENE and dip 35° north. Minor mineralisation follows other elvan contacts and sets of later steeply dipping fractures. The localisation and overall geometry of the deposit is explained in terms of the complex structural geology of the Lower Palaeozoic metasediments and the shape and manner of emplacement of the invading Hercynian granite of Cornwall. Variations in the thickness and grade of the orebody, and in the nature of the mineralisation, are shown to be structurally controlled by undulations of the footwall contact of the B elvan. Wallrock sericitisation is present and is applied in exploration for ore

Dec 1, 1971

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 P Cochrane

Our ability to generate information and transport it about the planet on super highways of optical fibre is about to change the way in which we communicate, work and live. There is not a single aspect of our future that will go untouched by the communication and computing revolution that Is now upon us. The change we are about to witness will overshadow the impact of the printed word, industrial revolution and physical transport. The next major wave of information technology (TT) development will focus on the delivery of information and experience on demand, in the right form, at the right time, at the right price, to fixed or mobile terminals anywhere, over networks of optical fibre, radio, satellite and optical wireless. Bandwidth, distance and time will no longer be significant cost elements as service and access become dominant.

Jan 7, 1996

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 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 J. Ivon Graham, T. D. Jones

This paper presents methods in use in British coal-mines for the suppression of dust. While the effect of present-day treatment will not be apparent for several years, in pits in South Wales, concentrations as high as 50 gm./1,000 cu. ft. were some years ago fairly common in various operations at or near the coal-face, with an average concentration of 20 gm./1,000 cu. ft. Now the average concentration in what were previously dusty pits is probably not greater than 3 gm./1,000 cu. ft.Nevertheless, every effort must be made to improve conditions still further. In South Wales it is claimed that 99% of the coal-faces requiring treatment have been dealt with either by wet cutting, infusion, or hand-spraying. The extent of the treatment by these methods can be gauged by the fact that the total length of coal-faces now being treated by water infusion in Cardiff and Swansea areas is about 33,000 yds., by wet cutting 25,000 yds., and by hand-spraying nearly 14,000 yds. The influence of methods of mining upon dust production is only mentioned very briefly in this review, and there is no doubt that much more is to be learned concerning this aspect. It can be stated, however, that good mining practice is essential to prevent unnecessary dust production, and the problem of dust in mines will be solved only by the closest co-operation between mine managers, workmen, and scientists.

Jan 1, 1947

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

The Council of the Institution of Mining and Metallurgy submitted the report of the affairs of the Institution for the session 1970-71, and the Statement of Accounts for the year ended 31 December, 1970. The statistics given in the report refer to the calendar year 1970. Details are included of membership, officers, representation on other bodies, honours and distinctions, awards, meetings, publications, library, overseas activities, fellowships and grants, the revenue and expenditure account, the balance sheet, trust fund balances, contributing companies, and schedule of investments

Dec 1, 1971

By Briggs H.

The illustrated device uses the principle that the lamp can burn with a smaller inlet passage if the air is rich in O2 and that the size of the inlet can be made a measure of O2 percentage. The appliance consists of an adjustable cut-off applied to the inlet of a safety lamp of the improved Gray pattern. Precision is assessed from tables of calibration tests in air contaminated with blackdamp of CO2:N2 composiiton 1:5.67 at temperatures of 40-70 degrees F. Results are presented of tests at St. Germain's colliery, of tests in air contaminated with pure CO2 and of air contaminated with both blackdamp and inflammable gas; published ranges in mine-air blackdamp compositions are tabulated as ranging from 90.06% N2 to 43.90% CO2. When firedamp is present at 1.25-2.5%, its content must first be estimated by means of the cap and a fifth of its value then deducted from the lamp reading for O2

Dec 1, 1916

By J. C. Loretto

The philosophy and detail of mill design in developing countries, where it is frequently difficult to obtain experienced, qualified supervision to operate the plant, are discussed. The resulting design suggests the desirability of simple units, with maximum visibility of equipment operation and material movement, which allow the minimal technical supervision to see the plant conditions prevailing. Information on plant conditions during periods of lesser supervision can be provided by the use of simple, low-maintenance recorders. Where the mill is intended for operation in a developing country, it is insufficient for the flowsheets and plant layouts merely to be drawn: the process metallurgist must pay meticulous attention to details that could ordinarily be left to the design detailing group. The design of this type of mill requires a knowledge of human engineering—of the type of individual who will operate and supervise the plant; probable changes in personnel should be taken into account. Details are suggested for coarse-ore handling, screens, feeders, secondary and tertiary crushers, conveyors, dust collecting, fine-ore feeding, grinding mills, conditioners, flotation, thickeners, filters, reagent systems, sand pumping, sampling, instrumentation, safety and construction

Dec 1, 1971

By M. G. Fleming, F. Warner, R. W. Boswell, M. J. Cahalan

The annual dinner of the Institution was held at the Savoy Hotel, London W.C.2, on 22 April, 1971. The President, Mr. M. J. Cahalan, was in the Chair; members and guests numbered 320. The toasts of The Queen and Queen Elizabeth The Queen Mother, Prince Philip The Duke of Edinburgh, The Prince of Wales, and the other Members of the Royal Family were proposed and loyally honoured. R.W. Boswell proposed the toast of the Institution of Mining and Metallurgy, the president responded, Professor M.G. Fleming proposed the toast of the guests and Sir Frederick Warner replied

Dec 1, 1971

By R. Macleod, G. G. Bursey, T. R. C. Aston, J. E. Gale

In 1991 the problems of water inflow at the mine were addressed by a three-phase study. A three-dimensional finite-element computer code, CFEST (Coupled Fluid, Energy and Solute Transport), was used to model the system of groundwater flow around the mine, allowing assessment of the nature of the hydrological regime and of the various recharge mechanisms and sources of inflow. A regional (111 km2) model was used to simulate conditions of low to average mine inflow and provide boundary conditions for the subsequent local (16.8 km2) model. The regional model produced inflows of 0.26 m3/s and the local model 0.25 m3/s. With the use of constant head conditions to simulate a saturated flood plain along the Gays River and on doubling the rate of surface recharge, the local model produced a maximum mine inflow of 0.255 m3/s, in contrast to a measured peak mine inflow of 0.37 m3/s. The discrepancy suggests that during periods of high river level surface water gains access to features with high permeability, such as sinkholes, that may be connected directly or indirectly to the mine workings. Improved simulation of high inflow conditions can probably be achieved by determining the hydraulic conductivity of the river-bed and flood-plain sediments and modelling known sinkholes as discrete units. Possibilities for controlling the amount of inflow to the mine include sealing the flood plain with dykes, checking regularly for new sinkholes, which should be filled and capped, maintaining adequate mine drainage, and monitoring well levels and pressures on a continuous basis.

Jan 12, 1993

By Marshall Charles Riddell, John Carlon

local news

Jan 12, 1997

By J. Drzymala, K. L. Wolters, T. Chmielewski, T. D. Wheelock, D. H. Birlingmair

Microflotation tests were conducted with a modified Hallimond tube equipped with a fritted glass disk and magnetic stirrer to determine whether the results would support an equation that predicts a linear relationship between particle size and the reciprocal of particle density in water for a specified flotation recovery in a given time. Data obtained with the tube for either hydrophilic or hydrophobic solids fit the equation satisfactorily. It was also shown that the natural flotability of molybdenite is somewhat less than that of elemental sulphur and that sodium dithionite is a good depressant for sulphurised pyrite. In addition, it was found that the untreated pyrite and galena used in the study were hydrophilic and did not float by particle-bubble attachment.

Jan 4, 1992

By D. C. Cooper, P. M. Green, J. A. Plant, P. R. Simpson, A. J. Reedman

Paper presented at the 28th International Geological Congress held in Washington DC, July 1989 (International geochemical mapping sessions). The Grampian Highlands and English Lake District evolved as part of the American and European continental plates, respectively, and were separated by the Iapetus Ocean until they were tectonically juxtaposed during the late stages of the Caledonian orogeny. The similarity in the controls of the distribution of gold pathfinder elements and gold mineralisation in the two regions thus provides important information for understanding the genesis of gold deposits in comparable tectonic settings elsewhere. The data presented are inconsistent with models that invoke a juvenile source of gold or its pathfinder elements. Instead, they support a model whereby gold and its pathfinders were initially concentrated in volcano-sedimentary sequences in rapidly subsiding, tectonically controlled basins and in associated volcanic rocks. Remobilisation and mineralisation occurred subsequently, probably as a result of an increase in oxygen fugacity associated with the influx of granite magmas into the crust and the establishment of hydrothermal convective circulation systems

Jul 1, 1991

By P. R. Ineson, D. W. James

For a criterion to be useful it must either demonstrate directly the role of exhalative processes in the formation of a deposit or describe a unique attribute of exhalative deposits. Few of those employed in previous investigations entirely satisfy either condition. The limitations of three of the most frequently employed criteria are illustrated by studies of the geology of the King Island Scheelite deposit in Tasmania.

Jan 12, 1993