GASES FROM CERTAIN EXPLOSIVES. 95 



" The cost is insignificant compared to the valuable results obtained, 

 and under the circumstances some system of artificial ventilation should be 

 adopted in practically every mine on the Rand. Not only from a health 

 point of view, but from an economical point of view, the ;^25,ooo spent has 

 been repaid us many times over."* 



Of course, some mines' are mvich worse in respect of 

 ventilation than others, and some again are very bad, but on 

 account of their short hves it is not worth while to equip them 

 with ventilating' appliances. On the whole, however, I do not 

 believe that the mines of the Witwatersrand are worse than 

 those of other parts of the world, and they are certainly better 

 than most. Matters have undoubtedly improved also since 

 the system of doing all the blasting on one shift was adopted 

 — generally the day shift. During the night the mine, being" 

 practically empty, has, therefore, a chance of getting filled 

 up with fresh air. To all who are interested in this subject 

 I would strongly recommend a perusal of the report of the 

 Commission, to which I have already referred, and so far as 

 our particular subject is concerned, the following recommenda- 

 tions, if put into effect by legislation, will be the Miners'^ 

 Magna Charta. 



" (a) That the legal maximum for noxious CO., permissible in mines in 

 the Transvaal be fixed at 8 parts by volume in lo.ooo of air. 



" {'->) That an amount of 4 parts of CO.^ by volume in 10 000 of air shall 

 be allowed in addition to the aforesaid maximum as representing 

 innocuous CO._, normally present in the atmosphere. 



" (';) That where candles or similar illuminants are in use a further addition 

 of 3 parts of CO.^ by volume in 10,000 of air shall ue allowed as 

 representing innocuous CO.^ resulting from the combustion of 

 such illuminants. 



" (d) That in order to meet, from the point of view of practical adminis- 

 tration, difficulties in regard to possible innocuous CO,^ from 

 ' country rock ' and other uncertain sources in the mines of the 

 Rand, a further allowance of 5 parts per 10,000 be made, making 

 a total limit of 20 parts of CO. per 10,000 of air. 



" (e) That in the Lydenburg and other districts where there is geologically 

 strong presumptive evidence of a production of ground CO.,, early 

 investigation he undertaken by Government, and that a proper 

 and reasonable allowance be made therefor, the total amount 

 in the mine air not to exceed i per cent, by volume."! 



With these recommendations I must associate myself in a 

 most wholehearted manner. 



* Proceedings of the Chemical, Metallurgical and Mining Society, " Venti- 

 lation and health conditions on the Mines of the Witwatersrand, with special 

 reference to the Ventilation System of the East Rand Proprietary 

 Mines by S. Penlerick, Member. 



t Page 266. Vol. I., Final Report, Mining Regulations Commissicn. 



