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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 E R. Hassall

Discussiong the importance of minerals and mining, impacts on the environment and remediation, and the need to foster interest in science among young people.

Jan 8, 1997

Discussions of the papers with a written contribution on Paper No. 11 and authors' written replies. Also brief obituary of Dr. T. David Jones on p146.

Jan 1, 1947

By M. Schwartz

Mining in Argentina is diverse in terms of the number of minerals extracted from the country, but also in terms of the varied approaches and attitudes of mining investors and their trust in the country's individual provinces. Laws are discussed, investment attractiveness and taxation.

Jun 1, 2015

By J. A. Saunders, E. L. Rowan

It is now widely accepted that the metal-rich waters found in the oil wells are possible present-day analogues of the mineralising solutions that formed the Mississippi Valley-type (MVT) deposits throughout mid-continental USA and elsewhere. A study characterising the trace-metal content provides additional circumstantial evidence for a genetic link between sediment-hosted mineral deposits and basin brines: Ag, Co, Ni, As and Mo, detected in the scale, are locally present in accessory minerals in MVT deposits and the levels of Ag found in the wells support the conclusion that sedimentary sources for silver should be considered in evaluating the origin of Pb-Zn-Ag deposits in sedimentary terrains

Jun 12, 1905

By C. P. Summerhayes, J. W. G. Gilbey, S. Henley, G. P. Glasby, J. J. T. Harvey, J. Larsson, O. Akiman, A. G. Brown

Abstracts are presented from six University of London, one University of Nottingham and one University of Durham PhD theses

Dec 1, 1971

Discussion of the paper published Trans Inst. Min. E., 1916, vol. li., page 99 comprises a written comment by Bolton H. giving two examples of the faunal evidence for deep-water vs littoral conditions of Goniatites (cephalopods) and Upper Old Red Sandstone fishes

Dec 1, 1916

By S. V. Shiraishi, H. B. Bell

Report of discussion at February, 1971, IMM general meeting (Chairman: M. J. Cahalan, President) of a paper published in Transactions/Section C (Mineral Processing & Extractive Metallurgy), vol. 79, June, 1970, pp. C120-C127, with a contribution by Wright P.A. on the miscibility gap

Dec 1, 1971

By C. C. Harris

The use of Alyavdin's equation Y(x,t) = 1-e(-bt) for describing the effect of grinding time on size distribution is discussed. The equation transforms into linear form by expressing it as log-log reciprocal (1 - Y) versus log t. For plotting, specially divided grids are available; Rosin-Rammler or Weibull charts may be used. The data of Herbst and Fuerstenau are especially useful for illustrating the Alyavdin-Weibull chart in two applications: (1) presenting data (which are relatively unaffected by experimental scatter) and comparing them with theoretical predictions, and (2) as a test for the zero-order kinetics production hypothesis. The chart based on the Alyavdin-Weibull equation is suggested as a useful aid in the analysis of kinetic data (/ versus f), though not as a procedure in its own right. Proposed applications are (1) displaying data with excellent clarity, since it avoids the kind of congestion inherent in some other plotting methods, and (2) as a test for assumed kinetic relationships. Sometimes, equation 1 describes the data quite closely, and in these cases the parameter values appear to be related to certain operating conditions.

Dec 1, 1971

Further discussion at the Mniing Institute of Scotland's annual general meeting held in Glasgow, 8th April 1916, of the paper published in Trans. I.Min.E. vol li, 1916, p.169-186 with discussion p.187-188, included oral and written contributions by McLaren R. and Waddell H.

Dec 1, 1916

Two of the most important economies in coal-washing are in the actual washing of the coal and in a proper lay-out to reduce to a minimum the cost of labour for handling and washing. A guarantee is usually required for turning out a washed coal containing not more than 2% of free dirt and a resulting refuse with not more than 2% of free coal; any plant that gives results within such guarantees can he considered economical, provided that there are no other losses during the washing process. Various drainage arrangements and washery lay-outs are illustrated and discussed with respect to drainage, bunkers, sieves, settling tanks and conveyors and two further points considered: siding accommodation, which may become quite important with washeries of large capacity especially when the coal is brought in railway-wagons; and the irregularity with which the coal arrives. (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)

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 S. Y. Ezz

Report of discussion at February, 1971, IMM general meeting (Chairman : M. J. Cahalan, President) of a paper published in Transactions/ Section C (Mineral Processing & Extractive Metallurgy), vol. 79, September, 1970, pp. C226-C233 with contributions by Wild R. and Astier J. on fluidised bed reduction of iron ore fines

Dec 1, 1971

By C Selcuk

This item considers the work of the CleanMine consortium on the removal of hard scale from valves via the combined use of controlled acoustic cavitation with guided wave propagation.

Jun 1, 2015

By G Fakes

This paper describes the history of civil engineering tunnelling and developments in soft ground techniques during the 19th and 20th centuries, culminating in the design and use of high speed tunnelling machines for all types of ground conditions. Some of the problems encountered are outlined, and descriptions are given of some contemporary developments in rock tunnelling techniques, with comparisons of methods used in the mining industry.

Jan 5, 1996

By A. Sutherland Strachan

Before regulations governing the work on the mines, it was not uncommon in the Rand for a miner to die within a period of 2-3 years as the result of exposure to dust. This paper considers mine and tunnel conditions promoting silicosis and measures to avoid dust exposure in the Rand, South Africa.The relationship between blasting and lung lesions is explored. Evidence is presented that improved working conditions and lowered dust levels reduce the incidence of silicosis.

Jan 1, 1947

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 A. Policard

The bodies of mammals possess a very efficient mechanism for ridding themselves of inhaled dust. When the lung is healthy this mechanism works very well, and dust is quickly and completely expelled from the lung either by the respiratory tract or the lymphatics. The mechanism, however, is easily upset, and slight alterations in the condition of the ciliated epithelium or the circulation of lymph are sufficient to interfere with it, therefore the second mechanism comes into play and the dust is fixed and immobilized in some part of the lung. This, however, is not a real cleansing process, since the lung becomes a dust-trap, and may become'pneumokoniotic. The mechanism is protective at first, but later, when the accumulation of dust is considerable, it gives rise to trouble. The lung cannot become, so to speak, a physiological dust-trap, and still retain its normal structure and function; pneumokoniosis begins, which is essentially a disease due to the mechanical presence of large amounts of inert foreign material.

Jan 1, 1947

By B. Denby

sintered ores, to be removed by a pneumatic,

Apr 1, 1995

"Prior to the publication of the General Report of the Miners' Phthisis Prevention Committee of South Africa in 1916 little attention was paid to the dust hazard and the necessity for its suppression in the underground workings of the Broken Hill mines. Such precautions as were observed for the elimination of dust were related rather to the prevention of lead poisoning, which, in the early days of Broken Hill when large tonnages of lead carbonate ore were being won, was rather prevalent. Ventilation and hygiene followed the general practice in this and most foreign countries.This paper covers incidence and action since 1918, considering medical aspects and operating aspects. "

Jan 1, 1947