and engineering journal . fice for publication:— Owing to breakdowns of RockHoist No. 2 Shaft it is anticipated that the tonnage milledfor the month will be reduced by 4,000 tons; repairs expectedto be completed to-night (12th instant); publish immedi-ately. Jburg, September 17. L921. THE MINING AND ENGIN] JOUBNAL Sampling, Analysis andClassification of Coal. The following is a summary of an article on the abovesubject appearing in a recent issue ,,f the Journal of theChemical, Metallurgical and Mining Society of South Afrit a Sampling. The sampling of material, whether i
and engineering journal . fice for publication:— Owing to breakdowns of RockHoist No. 2 Shaft it is anticipated that the tonnage milledfor the month will be reduced by 4,000 tons; repairs expectedto be completed to-night (12th instant); publish immedi-ately. Jburg, September 17. L921. THE MINING AND ENGIN] JOUBNAL Sampling, Analysis andClassification of Coal. The following is a summary of an article on the abovesubject appearing in a recent issue ,,f the Journal of theChemical, Metallurgical and Mining Society of South Afrit a Sampling. The sampling of material, whether it consists of ,?. al,ore, or any other product, is the most important feature inaiming at a true value of the material. In the case of coalwhich has been mined, one has an aggregate of coal, shalepyrite, and perhaps other impurities ranging in size fromseveral inches down to particles of microscopic size. Thebreaking up of the coal and its impurities into these differentsi/es depends entirely upon the physical character of tin-. On a Transvaal Colliery. various constituents which make up the aggregate. In thesampling of such a mass it is therefore important that eachconstituent be correctly represented in the sample. Thebigger the range in size between the various pieces whichmake up the coal, the greater must be the sample in orderthat it shall be truly representative. The bulk of the samplecannot be reduced unless the size of the pieces is correspond-ingly reduced. Hence in order to reduce a sample to labora-tory size, each quartering down must be preceded by areduction in size of particles. The errors introduced byincorrect sampling are much greater than those possible byslip-shod chemical analysis. Analysis. The determinations usually made in the analysis of coalare: (1) Calorific value, (2) moisture, (3) volatile matter andfined carbon, (4) ash, (5) sulphur. In the determination of the calorific value variouscalorimeters are used, but the most reliable and useful isthe B
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Keywords: ., bo, bookcentury1800, bookdecade1890, booksubjectmineralindustries
