Interim report of the Miners' Phthisis Prevention Committee = Tussentijds rapport van de Kommissie ter voorkoming van mijntering.

  • South Africa. Miners' Phthisis Prevention Committee.
Date:
1913
Catalogue details

Licence: In copyright

Credit: Interim report of the Miners' Phthisis Prevention Committee = Tussentijds rapport van de Kommissie ter voorkoming van mijntering. Source: Wellcome Collection.

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    immediately after blasting. The most important inference is, that the currents of air in a mine, and the sequence of blasting, should be so arranged that men >? need not travel in—much less remain in—a return air-way, after blasting has taken place. An experiment made in 1912 at the Village Deep Mine, near the exhaust fan by which the whole air circulating in the mine is drawn upwards, gave the follow- ing results :— Time. — Mallugrams. ae p. B. : 3°5 2.40 p.m. 1-0 Fan stopped part of time. 3.15 p.m. 9-0 Smoke appeared at 3°35 p.m. 4.40 p.m 12-6 5.45 p.m. 9-0 6.40 p.m. bbs 8.45 p-m. 3-0 The effect of blasting on the amount of dust in the air is here clearly seen; but ‘the amount of dust is very much less than in the case of the Aurora West return alr-way. The amount of dust in the upcast air of the Simmer Deep Mine was measured by Mr. MeArthur Johnston at the top of the shaft, both before general spraying was installed underground and afterwards. The results are interesting : — é : April, 1912. | September, 1912. September, 1911. With sprays, and | With sprays, and . Without sprays p : Time. Milli ATA, wetting. | wetting. To kens Milligrams. | Milligrams. otal Dust. Total Dust. | Total Dust. (Mineral. ) (Mineral. ) (Mineral. ) ERO LO am... Sr 2800 ae 3220 Sd 11.30 a.m. to 12.30 p.m. … 130°0 21:0 0°2 SPAR too pm. =... pra elan 80°0 39°0 2° Ir. 4.15 pm.to5.15 pm ... 100-0 | 14°0 yea It will be seen that the introduction of sprays im the underground workings had a marked effect on the amount of dust in the air which had circulated through the miue. More recent experiments in the upcast air of mines, at times other than im- mediately after blasting, show very small quantities. Thus, at the City Deep, the average of 15 experiments was 1-6 milligrams. At the Brakpan Mines, the average was 1:5 milligrams. ; . (e) General. The amount of fine dust in the air of Johannesburg, as ascertained from 18 measurements taken in the streets during April and May, 1912, ranged from 2 milligrams to 16-5 milligrams of mineral dust. If these measurements had been taken in the same manner as in foreign cities, merely total dust, the results would have been much higher. The average amount of dust (total), present in the streets of Paris, is quoted at 7-5 milligrams, or, after eight days of dry weather, 23 milligrams. This is reduced to 6 milligrams after heavy rain. Hesse* states that in an iron foundry there are present from 72 to 100 rt. grams of. mineral dust, and in an iron mine about 14 milligrams. (These esti- mations are, presumably, total dust) * See Dr. Soper’s “ Air & Ventilation of Sub- „ways, page 201.