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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

By R. Phillips

The low concentration of diamond in workable deposits requires very large samples for grade estimation, and results, even then, may be erratic and difficult to interpret. Although the Poisson probability distribution cannot accurately describe the occurrence of diamond, it is suggested that it gives a better estimate of grade than conventional methods, even from single samples. Examples illustrate the simple calculation required.

Dec 1, 1971

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 G. E. Pearse

Reports, discussions, a written contribution and two written replies are presented from 11 sessions on: Safety and compressed air; Ground movements; Geotechnical; Channel Tunnel (2 sessions); Machines; Case histories; Transport tunnels; Case studies; Site investigation; and Undersea tunnels

Jun 13, 1905

By A. Ludkin

The paper presents the history of the occurrence of spontaneous combustion in the north area, together with the associated problems. These are examined and a description is given of the methods used to combat the danger, including the use of modern scientific instrumentation. Detailed reference is made to the underground trials with pack injection and sealant coatings which were carried out at Seafield Colliery following the formation of a working group to assess the performance, in the same underground conditions, of (1) sandbagging, (2) pack injection, (3) surface coating. Based on these trials, an improved and more economical method of prevention has been established. There is, however, still scope for further improvement in techniques which would take into account the problems of gradient, transport, manpower and cost.

May 23, 1905

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 W. R. Chambers

A wide variety of mining conditions exists within the South Midlands Area and across this range of conditions more than one half of the mines are highly susceptible to spontaneous combustion. Two thick seams in which the greatest risk exists are described and illustrated. The different heatings which take place are categorized by the locations at which they occur in the mines: additional special cases not easily categorized by location are discussed separately. The discussion for each category of heating follows the pattern of: (i) the reasons why it occurs; (ii) when it arises the means by which it is fought, and (iii) the preventive measures taken in an attempt to avoid its occurrence. Relatively new factors which may affect the incidence of heatings are highlighted and suggestions are made which may assist in reducing the number of incidents in the Area. A new method of continuous sampling, analysis and recording is described and mention made of an original method of interpreting carbon monoxide results with the aid of the computer. The first results from this work show that an early warning is given of an adverse change in trend several weeks earlier than with the present methods. Lastly, suggestions are made about the direction in which research might proceed to assist in reducing the special hazards created by several features inherent in the present methods of mining.

May 23, 1905

By M. Schwartz

Hosting copper, gold, oil and liquefied natural gas, the country is an interesting target for miners. However, remote locations in inhospitable, unusual and difficult terrain cause problems. The government has worked to create a Sovereign Wealth Fund to manage government surpluses from minerals and energy but PNG scores very low among many criteria, including land dispute resolution, as revealed by the 2014 Canadian Fraser Institute in its survey of senior mining personnel.

May 1, 2015

By R. G. Jones

At its peak in the 1970s, South Africa was responsible for around 80% of global gold production and, according to the US Geological Survey, it still has the largest share of gold reserves - as well as 90% of the world's platinum. But, in January 2015, gold production reached a new monthly low, generating 87% less than it did in January 1980, and South Africa is now the world's sixth ranked gold producer. What next for African gold?

Jun 1, 2015

By T. Guyaguler

An analytical technique using computer-based multiple-regression methods was employed to determine the relation between the dust-producing index and inherent rock properties of typical samples from a coal-producing area, one of the aims being to provide a preliminary predictive tool for practical use. The investigation demonstrated that factors varied in their influence under different conditions, the brittleness:toughness ratio and the hardness being the most significant inherent properties with hardness showing the highest positive correlation coefficient

Jun 13, 1905

By Fergusson E.

An account is given of the history and operation of the Straits Tin market and the Penang price. The procedure by which the official ruling tin price is determined is presented and the way in which bids are treated is outlined: the price declared in Penang is the result of a joint operation by the two Malaysian smelters and is arrived at by finding the highest price at which the whole of the day's offerings for sale can be sold, thus reflecting the marriage of the offerings of the individual mine producers with the demand for Straits Tin from the consuming countries of the world. A system of accurate weighing, sampling and assaying of concentrates delivered to the smelters' premises enables the various ore-buying agencies of the two smelters to notify their central offices promptly of the estimated tin content of the concentrates their customers wish to price that day, so that by 11.00 a.m. both smelters will have exchanged with each other figures giving the total quantity of metal they have for inclusion in the day's market, at the same time exchanging particulars of the bids they have received. Miners are encouraged to sell regularly for cash and an evenness is thus achieved which avoids large daily fluctuations in overall quantity.

Dec 30, 1971

By J. Gough M. D.

There are many points still obscure regarding the nature of coal-workers'- pneumokoniosis, but the interpretation of the disease has been greatly clarified in recent years. It is now known that exposure to fumes or gases or other conditions peculiar to coal-mining are not necessary factors in the production of pneumokoniosis. The same disease occurs in coal-trimmers working in the docks, and it is thus established that the inhaled dust is the primary factor. On the other hand, there is no completely satisfactory explanation of the distribution of the disease. Geological and petrological studies have not given an unequivocal explanation of the difference in incidence in different parts of the coalfield. It is an open question whether the quantity of dust inhaled is more important than its chemical composition. However, there is ample evidence from the medical side that elimination of dust and of tuberculosis from the environment of coal workers will be required to prevent pneumokoniosis. Much is being done with regard to elimination of dust, and a similar energetic action is required in regard to tuberculosis.

Jan 1, 1947

By Garforth W.

The chairman announced the new government duties of the out-going President, Sir Thomas Holland, and the formation of a new standing committee on mining to advise the Advisory Council for Scientific and Industrial Research on suitable projects for grants. Some of the potential lines for investigation into the best methods of winning and presenting coal in the best commercial condition include wasteful practices in operating steam boilers, national loss due to neglecting recovery of coal by-products, and the leaving of large areas of coal for fear of spontaneous combustion or as boundary pillars and support

Dec 1, 1916

Discussion of the paper presented at the Manchester Geological and Mining Society's general meeting held in Manchester, April 11th 1916, with Mr. Leonard R. Fletcher, President, in the chair, included questions asked and points for discussion raised by Bramall V., Paton J.D., Fletcher L.R., Siddall F.N., Stoker A. and Stone T., in particular on how to eliminate dust

Dec 1, 1916

By J. R. Budden, P. A. Spencer, J. Barrett

The initially produced arsenic (III) is very toxic to the unconditioned culture but the mixed culture has the capacity to oxidise it to arsenic (V) in the presence of iron (III). It was possible to build up the resistance of the culture through progressive sub-culturing on arseno-pyrite until it could tolerate steady-state concentrations of 30 mM arsenic (III) and 200 mM arsenic (V). With some samples tested in the continuous systems the final arsenic concentrations reached 330 mM. It proved possible to use the laboratory batch data to establish the optimum operating conditions for continuous test systems with capacities of up to 32 m3. Data on the residence time, oxygen uptake rates and gold extraction from the bio-oxidised residues could then be confirmed by continuous testing without the need first to use empirical means to determine optimum conditions for continuous bio-oxidation. The data on residence time, oxygen uptake rate, solids density and neutralisation could be used to estimate the capital and operating costs of treating any given tonnage of the concentrate of interest. It was established that the arsenopyrite concentrates can be suitably bio-oxidised to cause the liberation of at least 90% of the gold content. The method is simple to operate and is flexible over a wide range of external conditions

Apr 1, 1991

By Ruddle R. W.

An outline account is given of the smelting of copper and the chemistry of the process. A table provides compositions of the more important minerals from which copper is won by smelting. Roasting is discussed as is smelting using reverberatory furnaces, blast furnaces and flash smelting. A brief discussion of converting covers the upright (Great Falls) converter and the horizontal (Peirce-Smith) converter.

Jan 1, 1953

By S Colak, M Tunc, C Celik, M. M. Kocakerim

The most important parameters affecting the solubility of ulexite (sodium calcium borate) in H2SO4 were found to be reaction temperature and solid:liquid ratio, in that order. Dissolution increased with increase in temperature and stirring speed and with decrease in solid:liquid ratio, particle size and acid concentration, the last effect as a result of decreased precipitation of CaSO4 on unreacted particles. Optimum conditions, in which around 99.5% of the ulexite could be dissolved, were a reaction temperature of 60 degrees C, a solid:liquid ratio of 1:8 g/ml, an acid concentration of 8 mol/l, particle size smaller than 425 micrometres, a stirring speed of 52.33/s, a reaction time of 1 800 s, a calcining time of 3 600 s and a calcining temperature of 170 degrees C. These conditions, determined by the Taguchi method, are reproducible in a commercial production environment

Jun 21, 1905

By L. J. Barnes, R. O. Koch, J. H. Versteegh, C. J. N. Buisman, P. J. H. Scheeren

Several water treatment options have been studied and piloted. A process based on activity of sulphate reducing bacteria combines sulphate removal and heavy metal removal in one process step. The anaerobic bacteria reduce the sulphate to sulphide and consequently metal sulphides will precipitate. The final design for the commercial scale plant is described.

Jan 12, 1992

By E. L. Evans

The historical development of South Yorkshire mining is traced and note made of the liability to generate spontaneous combustion of some of the seams which have been worked. The liability factor is analysed firstly as an inherent property in the material of a coal seam, and secondly as a circumstance of a situation in which access is provided for the air necessary to sustain oxidation. The geological settings in which incidents of heatings have been known to occur is discussed and conditions favouring a natural pre-disposition to spontaneous oxidation exposed, particularly the effect of argillaceous material overlying the seam. An extensive strata-dynamic study follows to demonstrate the situations in which stray air currents tend to impinge on readily oxidizable material. Prevention techniques are indicated as the identification of strata-dynamic situations in which air access to broken coal is induced and thereafter th operational action to seal off the voids which have been opened up so as to exclude air from the broken coal. Measures to reduce the tendency for ventilating air to short circuit across waste voids, and to obviate deflection of air into packs are outlined. The importance of face and roadway design features is demonstrated and the consequences of practices inimical to good control of spontaneous combustion are related. Discussions on means of detection and also on the sealant materials available are included.

May 23, 1905

The Aredor mine employs conventional dragline methods to exploit alluvial diamond deposits. Production began in 1984 with the policy of mining in the terrraces during the wet season and in the river flats during the dry season. Early production failed to meet predicted grades. A major geological programme to re-evaluate existing reserves was undertaken. This resulted in considerable increases in reserves in the river flats. Many of the reserve blocks included flats on both banks of the Baoule river. Methods of access into the river flats, normally flooded in the wet season, were developed to allow mining throughout the year. River diversions have been the main method used to provide access into the reserve blocks and, most importantly, to remove the risk of flooding. Aredor has carried out six main river diversions with a total length of 12 km. The diversions allowed production planning to be made on the basis of the economic evaluation of the reserve blocks, without undue regard to natural ground conditions or to seasonal factors. The Manning equation was used for the calculation of channel dimensions and gave satisfactory results. The practical aspects of the diversion preparations and flooding prevention are described

Sep 1, 1991