Search Documents

By C R. Ferrari

Residual subsidence is generally accepted as being about 5% of the total subsidence occurring within 12 months of all mining finishing. This paper looks at five case studies from different parts of the country, in various mining settings within a depth range of 430m to 760m. From a single seam single panel working to working the eleventh seam, all are within the concealed coalfield, similar to today's mining. The monitoring of subsidence continued for many years once the mining had finished and the results obtained are at considerable variance from the accepted norm. Subsidence has been found to carry on for up to eleven years after mining has ended, within a range of 8% to 45% of total subsidence. A highly significant factor was that subsidence, as a whole, was generally much more than predicted. The residual subsidence aspect has to he viewed in this context and in order to debate the subject at length, the causes of residual subsidence have to be balanced against the apparent inability to accurately predict subsidence. The results from the case studies were similar, even though the mining settings differed considerably. Subsidence of around 10% to 20% continued for several years after mining had ceased.

Jan 7, 1997

By G. D. Nicholls

There have been very few attempts to isolate the various factors that contribute to the overall imprecision of geochemical analytical procedures, due in part to the difficulty of distinguishing between them. The technique of spark source mass spectrography permits a ready distinction between the contributions to overall precision from sampling error and instrumental and other errors. With conventional methods of sample preparation for this technique sampling difficulties are responsible for 80-90 per cent of the overall imprecision. Examination of the probable location of the major difficulties in sample preparation indicates that the preliminary stage of grinding, mixing and extraction of a first aliquot (about 1/100 of the original sample) is generally perfectly adequate. The difficulty lies in the subsequent stages of sample preparation. Dry mixing techniques are unlikely to give good precision if the sub-samples actually examined by the analytical technique are less than 10 mg in amount. Solution techniques are less prone to sampling difficulty. Fusion techniques, unless conducted with great care, can produce more difficulty than dry mixing. Sample preparation is critical to the success of many analytical procedures. Selection of appropriate sample preparation techniques requires just as much care as the selection of techniques for the actual analysis.

Dec 1, 1971

By J. Temporal

An introduction to the conference material in this issue is given together with the issue contents list, closing remarks by its chairman Dr. J. Temporal, the list of contributors and their companies, and the information that the 26th Sir Julius Wernher memorial lecture had had to be presented by the lecturer's wife, M. Biggart, in his absence due to site problems on the Storebaelt project

Jun 16, 1905

By Mohammed Ali Shah, Martin Waller

The mining industry depends to a large extent on the availability of high performance equipment. For drilling this means a requirement for well engineered, reliable machines with mechanised handling and widespread utilisation of automatic control. Such machines enable performance optimisation of drilling operations and integration into a high productivity mining system. A review is presented of the current status of drilling technology as applied to the mining and minerals industry. This covers developments in: drill bit materials and design; drilling techniques; machine design; mechanisation; automation; and drilling control. It also covers the ways in which current and future mining methods and practices will influence the applications and demands placed on drilling activities. The probable impact of current research on the industry is discussed.

Jan 12, 1992

By J. A. Franklin, E. Broch, G. Walton

To make the best use of rock core, the mechanical character of the rock should be evaluated concurrently with conventional geological observations. The advent of simple techniques, such as the point load 'nutcracker' test, makes field logging of mechanical properties competitive with sampling and testing in the laboratory

Dec 1, 1971

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 D. F. Ball, P. R. Dawson, J. T. Fitton

Report of discussion at December, 1970, IMM general meeting (Chairman: M. J. Cahalan, President) and contributed remarks on the paper published in Transactions/Section C (Mineral Processing & Extractive Metallurgy), vol. 79, September, 1970, pp. C189-96, plus the authors' replies. Contributors included Cohen E., Hope B., Wasse D.G., Shakespeare A.G., Burwood D.S., Jones H.A., Dartnell J., Carter G.C., Henderson T.A., Relf G. and Clark S.W.

Dec 1, 1971

By E. A. Brocchi, D. H. Gameiro, P. K. Jena

Carbon tetrachloride was found to be a very efficient chlorinating agent for anatase concentrate, even at the low temperatures that were investigated (250-400 degrees C). For example, at 400 degrees C about 90% of the anatase concentrate was found to have been chlorinated within 60 minutes

Jun 13, 1905

By D. C. Yates, G. V. Jolliffe

In the five coalfields of Staffordshire, there have been some 43 incidents of spontaneous fires and heatings which have required special attention in the past ten years. This total excludes incidents in the Thick Coal Seam of South Staffordshire, which was worked until 1967, and which was subject to an almost continuous series of heatings. The incidents have been classified to show the sites of occurrence, the contributory factors which may have caused them and the treatments applied to them. The remedial techniques, as practised in Staffordshire, are dealt with in detail, with particular reference to standard methods of stopping-off. Precautionary measures taken are described, including a "liability to spontaneous combustion" classification of all seams, and the setting up of an emergency organization with emergency stocks of materials and equipment. The paper is concluded by a few words on the organization and control at the time of an incident.

May 23, 1905

By Simons W.

The object of the paper is to describe the standards of quality that should be specified in ordering material ordinarily required for colliery use, and also the qualities most suitable for particular purposes. Tables are presented of British Standard tests for wrought iron grades A, B and C, Admiralty tests for iron in chain, the quality of material for wheels and axles, and the composition and mechanical properties of wrought iron, Armco (ingot) iron and drawbar-gear steel. (Paper presented at the North Staffordshire Institute of Mining and Mechanical Engineers' general meeting held in Stoke-on-Trent, March 27th 1916, Mr. John Gregory, President, in the chair)

Dec 1, 1916

By L. R. Chimimba

"The Trojan nickel deposit occurs within a pile of ultramafic lavas subjected to a lower amphibolite grade of metamorphism. The lavas form part of the Upper Greenstones (Bulawayan Group) of the Mazoe greenstone belt. The nickel mineralization occurs as disseminated, massive and near-massive sulphides. The massive and near-massive ore occurs along the basal contact of the serpentinite units and is overlain by the more abundant disseminated ore, which occurs within the serpentinite. The main sulphide minerals are pyrrhotite. pentlandite and chalcopvrite. Minor amounts of millerite and pvrite are present. The Ni : Cu ratio in all three types of ore averages 15:1.The intercumulus nature of sulphides in the near-massive ore and similar textures occasionally seen in the disseminated ore indicates a magmatic origin of the mineralization. The basal position of the near-massive and massive ore suggests that the sul­ phides settled out under gravity during the emplacement and crystallization of a peridotitic magma. The deposit has been deformed and some of the primary massive ore has been remobilized into veins and breccias. The disseminated mineralization now occurs mainly as blebs of sulphides intergrown with silicate minerals or as stringers of sulphides between foliation planes in the serpentinite."

Jan 1, 1984

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 J. R. Hammond, I. C. Herbert

Report of discussion at October, 1970, IMM general meeting (Chairman: M. J. Cahalan, President) and contributed remarks on the paper published in Transactions/Section C (Mineral Processing & Extractive Metallurgy), vol. 79, June, 1970, pp. C128-36 and introduced by I.C. Herbert. Contributors were von Struve G., on the application of balling discs and the use of basic additives; Young P.A., asking for details of the drying, grinding, balling, induration and specification testing equipment and processes; Davison J. on pellet swelling properties and Carter G.C. on disc operation, refractories and green ball properties.

Dec 1, 1971

By A. L. W. Lips, B. P. J. Stevens, T. J. R. Bareley, E. Rothery, S. H. White

B.P.J. Stevens contributes a further response to the authors' earlier lengthy reply regarding their paper published in Trans.IMM B, vol.104, 1995, p.B1-B17, contending that despite the positive contribution clarifying their interpretations they perpetrate some misquotations, attempt to rewrite history and fail to understand the New South Wales Geological Survey's stratigraphic interpretation of the Broken Hill area. The paper's authors, in their further response, robustly defend their views, insisting that Stevens tends to misquote or take out of context what they have written and reiterating their findings that Zn is tectonically stacked above Pb at the north end of the orebody, that the written development of the stratigraphic interpretation is as they have stated, that shearing has attenuated or removed fold limbs in the Broken Hill block and that the 1:100 000 stratigraphic map reveals that magnetic anomalies are oblique to and truncated by the Geological Survey's interpreted stratigraphic boundaries

Jun 19, 1905

By P wade

This is the first Presidential Address given to the Nottinghamshire Branch of The Institution following the merger of the Nottinghamshire and North Derbyshire Branch of The Institution of Mining Engineers (IMinE) and the Midland Branch of The Institution of Mining Electrical and Mining Mechanical Engineers (IMEMME). I intend to review the formation of the individual institutions as well as what has been achieved by mining related institutions over the years and finally I intend to look to our future.

Jan 11, 1996

By I. Garba

The Bin Yauri deposit in the Zuru schist belt of northwestern Nigeria is a vein-type quartz-sulphide-carbonate gold mineralisation hosted by a brittle fault zone. The occurrence of the mineralisation in a contact zone of a Pan-African granitoid was believed to be sufficient evidence of deposition from magmatic fluids. However, studies may now indicate a metamorphic source for the mineralising fluids. A study of rare earth element geochemsitry was used to investigate the nature of the fluid-rock processes involved and identify the sources of the auriferous mineralising fluids.

Jan 12, 1992

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 Winmill T. F.

(Paper presented at the Institution of Mining Engineers' general meeting held in London on 8th June 1916.) The conclusions reached in this paper may be summarized briefly as follows: (1) The method of estimating moisture in coal by determining the loss in weight of a sample heated to 105°-110° Cent, in an air-bath for an hour is untrustworthy, the results so obtained being too low. (2) Dried coal has a very considerable power of absorbing moisture, and a sample, after being dried, must be protected instantly if it is to remain free from moisture. (3) A fairly accurate estimation may be made by heating the coal in a current of dry air at 105° to 110° Cent., and collecting the moisture evolved. (4) In cases in which it is proposed to use the dried coal for any further experiments, the drying must be done in the absence of oxygen, and this can be done simply and quickly by the vacuum method now described

Dec 1, 1916

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 N. A. Warner, R. K. Manna

Physical modelling of liquid-phase oxygen mass transfer in a water model of part of a proposed new polymetallic smelter has been achieved. A study of solute mass transfer caused by multiple, subsonic air jets contacting superoxygenated water flowing in a channel model of the smelter converting hearth has been carried out. For a wide range of channel flow rates the rate of mass transfer was found to be independent of water velocity. The water model has been used to compare mass transfer for both open-packed and close-packed multiple-lance arrays with circular nozzles of diameters 2.26, 4.95, 10.95 and 24.40 mm. It was found that with fewer of the larger-diameter nozzles a reduction of up to 58% in liquid-phase mass transfer occurred, especially for the close-packed lance configurations. This restriction of liquid-phase mass transfer would result in reduced metal losses in the analogous smelting situation. The larger nozzles, however, exhibited more jet-jet and jet-channel wall interference effects than their smaller counterparts, resulting in an effective reduction in the momentum fluxes of the impinging jets

Jul 1, 1991