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By R. R. Hart, R. A. Evans

This paper outlines the the methods currently being used in the West Wales Area for preventing the occurrence of any outbreak of spontaneous combustion. Stress is placed on the importance of correlating the position of a Rider Seam which is prone to spontaneous combustion. The recent introduction of the UNOR Recorder has contributed to the ability to monitor the CO content of the general body of the air during any incident. The use of modern sealants and improved methods of applying them have enabled the few instances of spontaneous combustion in South Wales to be treated promptly and efficiently. The authors describe the current spontaneous combustion problems at two collieries.

May 23, 1905

By G. Merrington, B. J. Alloway

Tailings from three historical mining areas in the UK were leached in columns under a simulated weathering programme which was chosen to represent periods of 1 and 2 years at 3 different ambient temperatures. The total concentrations of Cd, Cu, Pb and Zn in the primary ore minerals present in the tailings showed only a limited correlation with metal concentrations in the leachate. The leachate from columns of tailings that were maintained at a temperature of 25 (+/-3) degrees C contained, on average, 50% more Pb and 75% more Cu than leachate from tailings that were maintained at a temperature of 10 (+/-3) degrees C. The pH values of leachates from all three types of tailings at 25 (+/-3) degrees C were 0.2 units lower than those from columns maintained at 10 (+/-3) degrees C. The concentration of Cd and Zn in the tailings leachates showed no marked difference at the different temperatures. The composition of the leachate was found to be dependent on the type of gangue mineral, the presence of other sulphide minerals and the formation of secondary iron minerals. A comparison of the concentrations of heavy metals in the leachates produced in the laboratory with those in leachates that were collected in the field over a similar period of time from two of the mine sites showed that concentrations were of a similar order.

Jan 8, 1993

By R. W. Ruddle

The present state of knowledge on this subject may briefly be summarized as follows: (1) The copper content of the slag increases with the grade of the matte in contact with it; on the other hand, the proportion of copper lost decreases as the matte grade increases, because as a general rule a smaller volume of slag is produced when a high-grade matte is made. (2) The presence of CaO and MgO in the slag decreases the copper content of the slag, and the presence of ZnO increases it; the presence of A1203 seems to have little effect. The influence of the silicate degree is not yet clarified, but on theoretical grounds it seems likely that the copper content increases with the silicate degree of the slag. (3) High slag viscosity, high magnetite contents and low density difference between matte and slag all tend to increase the copper loss. The volume of slag is also an important factor. (4) The effect of bath temperature on the copper loss is not clear and further investigation of this point is needed. (5) It appears possible to recover a large part of the copper in the slag by adding FeS, CaS and other sulphides

Jan 1, 1953

"The Archaean komatiite-associated nickel sulphide deposits at Kambalda, Western Australia, exhibit a number of stratigraphic features that are indicative of a strong volcanic control on ore localization, including (1) a restriction to specific basal cumulate metakomatiite host units, (2) confinement within distinctive synvolcanic embayments in the footwall and (3) variations in the internal structure and composition of overlying and adjacent barren metakomatiite flow's and the distribution of interflow metasediments with proximity to the ore zones.The high magnesium content of the host units (up to 45% MgO volatile-free) in comparison with that of aphyric or spinifex- textured lavas (16-32% MgO) has been considered previously to indicate either magmas/lavas rich in intratelluric olivine or selective accumulation of olivine phenocrysts. The marked linear trend of the oreshoots, basal host units, footwall embayments and the volcanic stratigraphic relationships have been used as evidence for local linear feeding fissures. Rare relict igneous olivine in some host units is, however, demonstrably not intratelluric, and there is no direct or indirect evidence of a proximal eruptive site (e.g. footwall feeders, pyroclastic breccias, ultramafic intrusives) at Kambalda such as at some other deposits of this type. Kambalda is interpreted as a distal rather than proximal volcanic environment.Emplacement of the komatiite sequence at Kambalda was probably controlled by the locations of a few specific eruptive sites relative to regional topographic gradients and influenced by the topography of the pre-existing volcanic surface. Olivine enrichment in the basal host units occurred by in-situ fractionation and cumulus crystallization of olivine during longitudinal lava flow within linear lava conduits, possibly centralized on depressions between non-overlapping footwall basalt flows. The distinctive stratigraphic relationships are attributed to localization of lava conduits along the volcanic pitchline, flanked by more slowly moving parts of the flows. There are analogies with the physical volcanology of Modern basaltic and Proterozoic komatiitic lava flows.A corollary of this model is that the lava conduits thermally eroded and assimilated sulphidic sediments, contributing additional sulphur to sulphur-saturated komatiites or possibly inducing sulphide separation in originally sulphur-undersaturated komatiites. The latter would account for the restriction of ores to linear cumulate komatiite host units (thermally active lava conduits) and the locally mutually exclusive, but stratigraphically equivalent, relationship between the ores and sulphidic metasediments at Kambalda."

Jan 1, 1984

By B. Sonmez, B. Aksanl, S. Ersaym, I. F. Erkal, S. L. Ergun

The comminution circuit at the plant has experienced severe problems arising from a feed containing much larger amounts of clay and having a higher moisture content than expected. Three solutions were proposed: replacement of the crushing circuit by tooth roll-type crushers; using washing drums; and introducing primary autogenous/semi-autogenous millling instead of crushing. Computer simulations studied the effects of the first two solutions on the circuit capacity. Laboratory and industrial scale ball mill batch grinding tests were carried out. The parameters of a kinetic model were determined. The ball mill circuit was sampled and operating model parameters were calculated. The ability of batch grinding parameters to represent the operating conditions was studied. Tests failed to find acceptable model parameters, but parameters from an industrial size batch mill were found to be suitable for simulation studies. The simulations indicated that a continuous feed of -12 mm provided by tooth roll crushers would maintain the desired capacity. Increasing the feed size to -25 mm would reduce the capacity by 8-15%. The use of washing drums could also solve the capacity problem, but small fluctuations in water flow rates might result in problems of excess water in the grinding circuit.

Jan 4, 1993

By G Williams

Discussing equipment, systems of work, the need for updated programmes of local seismic exploration, and developments within the South Wales coalfield.

Jan 1, 1993

By D. J. Burdon, Anthony Caplan

"(1) The radiological appearances of pneumokoniosis on the Kolar Gold Field is described in detail. The characteristic abnormality is the. presence of a diffuse, fine annular and punctate mottling. (2) The frequency of symptoms could not be determined with any degree of accuracy, but it is believed that symptoms are absent and there is no incapacity until profuse radiological mottling is present, i.e., after long exposure to dust. (3) There is an increased predisposition to tuberculosis, which, if it occurs, affects the prognosismost unfavourably.(4) Pathological examination shows that the radiological mottling is due to the presence inthe lung of numerous small dust-cdll aggregates (up to T5 mm. in dia.) deposited around the smaller bronchioles and blood-vessels.(5) The dust-cell aggregates are relatively acellular but when tuberculosis is superadded thereis an excessive cellular and fibrotic reaction.(6) The difficulties of defining the radiological and pathological appearances of early pneumokoniosisare discussed.(7) The incidence of pneumokoniosis in 7,653 workmen with 5 or more years’ undergroundservice was 43-75%, but it is suggested that in future the incidence will be appreciably lower.(8) The methods of- dust production and the chemistry of mine dust are described. It isshown that the free silica-content of air-borne mine -dust is relatively low.(9) The aetiology'of the pneumokoniotic lesion is discussed."

Jan 1, 1947

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 R. R. Liebenberg, M. I. Brittan

The kinetics of the copper segregation process has been investigated. The experimental strategy used to isolate the rate-controlling reaction step is described. This step was found to be the chloridisation of the oxide copper minerals in the ore. The link between the rate of chloridisation and the overall rate of segregation is demonstrated experimentally. The influence on the kinetics of the various parameters in a TORCO system is examined and the implications are discussed

Dec 1, 1971

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 C. H. J. Beaven, M. P. Jones

Since the various new techniques of automation and computing have enabled vast numbers of mineralogical observations of relatively small samples to be made cheaply and rapidly, the statistical assessment of these measurements has become of vital importance. Much of the theory and most of the procedures of sampling that are used in the mineral industry are based on Gaussian statistics, but modern measuring techniques show that many mineralogical parameters do not necessarily follow the Gaussian distribution function. Consequently, it has become necessary to examine the application of other, more suitable statistical methods in order to derive the maximum amount of useful information from the examination of mineralogical samples. Some of the errors that can be introduced by the use of incorrect distribution functions are discussed and the value of determining the function that is appropriate to the particular parameter that is being measured is shown. Examples are provided of non-Gaussian distribution functions in mineralogical materials that were encountered during prospecting and during mineral treatment operations: a Canadian uranium ore, a Thai tin ore, and gold ore tailings.

Dec 1, 1971

By R. J. Pine

Procedures are described for the application of risk analysis or probabilistic methods to mining geomechanics. The methods are widely applicable to existing mine design models. Detailed examples are given of plane slope failure and of pillar design based on displacement-discontinuity stress modelling and empirical strength assessment. The modelling techniques assessed are the Latin hypercube sampling method, incorporated in a spreadsheet environment, and the general point estimate method (GPEM), programmed in TurboBasic. An example GPEM program listing is included. Both methods are very convenient to use. Probabilistic acceptance criteria for slope stability after Priest and Brown are examined and alternatives are proposed where output distributions of factor of safety are approximately normal or lognormal and output distributions of safety margin are normal. The reliability index is included as a useful measure of variability with proposed acceptance criteria.

Jan 12, 1992

By D G. Oldfield

Pall has developed and supplied to several airlines cabin air libers to provide clean air for passengers and crew in flight, while reducing airline operating costs. Most of today's modern commercial passenger aircrafts employ cabin air recirculation as a means of reducing operating costs. With large numbers of passengers being subject to an increasing proportion of recirculated air for hours at a time, the matter of cabin air quality, with particular respect to the health effects on passengers and crew, has to be addressed. Commercial pressure will ensure that the airlines and aircraft manufacturers will not revert back to the total fresh air systems of the 1960s and 1970s. In fact, feasibility studies are already being undertaken to look at increasing the proportion of recirculated air to 80% and above. With the application of specialist nitration technologies. Pall is able to ensure that the requirements for economy are met whilst ensuring that the air is effectively rendered as 'fresh air’ each time it is recirculated.

Jan 9, 1996

By NA NA

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

Jan 12, 1992

By L. J. Barnes, R. O. Koch, J. H. Versteegh, P. J. H. Scheeren, F. J. Janssen

Following two years of laboratory research with bench scale reactors, a 9 m3 experimental process demonstration reactor was installed at Budelco's zinc refinery to treat their underlying groundwater. A 600-fold scale-up was successfully achieved. It has demonstrated that this anaerobic microbial process can remove a wide range of heavy metals and sulphate to the required levels. Extended operation of the demonstration unit has shown that the process is robust, can withstand wide variations in feed composition, rapidly recovers from operational upsets and is easy to start up and shut down. The metal sludge produced can be processed in a metal refinery to recover both metals and sulphur.

Jan 12, 1992

By R. M. Honey

An attempt is made to summarise the mining law of England, Wales and Scotland. Attention is also drawn to the recent privatisation of the electric power and gas industries and the intention of the present Government to follow suit as regards coal mining. The subject of mining law is discussed under the headings: minerals or rights that have been nationalised or are vested in the Crown; ownership (of land and mineral rights); special customs; tracing of owners; right of support (arising from mining); ancillary rights and easements; obtaining prospecting and mining rights; planning permission; statutory aids to obtaining rights; notes on the history, law and practices of petroleum (onshore and offshore), gas, coal, prescribed substances, gold and silver; electricity; safety, health and welfare; and technical information and boreholes. A correction in the subsequent issue amends errors on p.A75 and A82 and regrets the publication of misinformation on the availability of grants

May 1, 1991

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 W. Petruk, M. J. Matos

An aplite ore from Guarda in northern Portugal, containing albite, microcline and quartz and muscovite gangue was studied to identify conditions for extracting the feldspar minerals. The large amounts of quantitative mineralogical data needed to evaluate grinding behaviour were provided by automated image analysis. The images were acquired on polished surfaces by measuring back-scattered electron signals produced with a microprobe. Minerals were identified from X-ray spectra and discriminated by grey level and element-characteristic X-rays. The quantities and size distributions of the minerals were determined by measuring thin sections of unbroken ore to predict the grind required to liberate the feldspars. The ore was then ground to -1.7 mm, polished sections were prepared from sieved fractions and the quantities of mineral species and apparent total liberation were determined by analysis. The predicted and measured liberations were compared and the grinding behaviour of the ore interpreted. In an appended correction, the correct version of Equation 1 is represented and Tables 3 and 6 are revised to consider all size fractions, including those coarser than 300 micrometres, in calculating the total liberation from King's fractional liberation

Jun 18, 1905

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

By M. Riddell

This paper describes the incipient heatings that occurred below ground in the High Main and Main seams at the mine between the years 1963 and 1966. The possible causes, effects and activities associated with such heatings are discussed in an attempt to establish the precautions necessary to minimize such occurrences. The assessment of as many "norms" as possible is made to enable the earliest detection and level of activity to be determined.

May 23, 1905