Report of the Coloured Labour Compound Commission appointed to enquire into the cubic amount of air-space in the compounds of the mines of the Witwatersrand.

Date:
1905
Catalogue details

Licence: In copyright

Credit: Report of the Coloured Labour Compound Commission appointed to enquire into the cubic amount of air-space in the compounds of the mines of the Witwatersrand. Source: Wellcome Collection.

Provider: This material has been provided by London School of Hygiene & Tropical Medicine Library & Archives Service. The original may be consulted at London School of Hygiene & Tropical Medicine Library & Archives Service.

    40/130 (page 14)
    Uliiiiites of Kvidence. Mr. J.R. ]] illiams. 20 Sep. 1904. {Dr. Turner,) Can you give us any explanation of the fact that two samples of the supplementary tests are nearly double the average ?—Well, it is rather unfortunate that during that night we took no outside samples, because, had we taken outside air samples the difference might be explained. Some time ago I was on another mine taking samples, and I found as high as .75 in the outside air. It was easily explainable, because there was a chlorination plant working next door, having two stacks, which would give off a large amount of carbon dioxide, and also a large amount of SO2, which would react in the same manner as CO2. These last three tests were put in by special request, but in their case samples of outside air weie not taken. I notice the outside air is very fairly constant, and only varies from •3 to -38 ?—We have had some cases in which the variations are considerably greater, but unfortunately not during the work of the Commission, although there is an abundance of authority in Europe to tell you that you will get up to 7 and 12 per 10,000 on a foggy night, which would very materially affect a sample of that kind. It is very unfortunate that these last samples only showed the purity of the air to a certain extent, because samples of the outside air were not taken. {Sir Kendal Franks.) You are speaking of the supplementary tests given at the foot of this statement ?—Yes. {Dr. Sansom.) I believe that when series i and 2 were done you had special arrangements at the door-ways ?—In all the samples except- ing the supplementary tests a special storm-door was put on as requested, and while speaking of that I would like to draw the Commission’s attention to the hrst set of samples where, instead of having ordinary ventilation, there was a louvre over the door with a hood over the stove- pipe which accounts for the very high results obtained on the hrst day. I was slightly at a loss to account for this, but on going to the same hut the following day when we were not sampling, I took an anemometer with me, and found that the air was going directly from the louvre to the hood over the stove- pipes in such a manner as to cause short-circuiting of the general ventilation, which is proved by the fact that two samples taken almost simultaneously in the same room varied from 0-97 to 2 • 14. On the next night, when sampling, the only alteration in the set of conditions was that the hood over the stove-pipe was lowered so as not to be more than five feet from the ground, which stopped the short-circuiting. We also proved that the gratings, instead of a louvre, over the- roof are a distinct disadvantage, and became very deleterious to ventilation, for fhis reason, that the grating acted as an intake, thus only circulating the air in the upper part of the hut. I therefore consider that the first set of samples should have been left out of the list, because the very same room, with small modifications, taken again on the 12th September, gave excellent results. It was then suggested to me that it might be thought that the hood was causing too much ventilation at one point. In the last set of samples I went purposely to the compound in the morning and prevented any fires being lit, and the result, therefore, shows what could reasonably be expected in the summer when there are no fires in the huts. I would like, however, to point out from 24 years’ ex- perience of the Kaffir, that you would not find these conditions in the summer, because the Kaffir will then sleep in the yard, and the doors and windows would be left open. {Dr. Turner.) I gather, then, from your remarks that this very high sample was due to the fact that there was a direct draught of air from the louvre right up to the hood ?—That is so. It was an experimental hut, which had never before been tried in this country. It was recommended for the test, so we gave the result of the analyses from those particular huts. And after that you modified the conditions by lowering the hood to within five feet of the ground ?—AYs, we made the hood telescopic, and brought it down lower so as not to exceed five feet from the ground, placing it just midway between the two tiers of bunks. And that condition was maintained after the first sampling right up to the end ?—Yes. So that when later on you got '78, the same conditions prevailed as in the sample in which you got -qi and -56 of CO2 ?—A'es, except that in the case of '91, giving a difference between the outside air of - 58 it was blowing a perfect hurricane, and on that night I particularly raised a very strong objection to that grating being put in the place of a louvre, because it was not ordinary ventilation.