SOMK UkcKNT VlKWS ON I'llE SuiMKCT OF MlNK VlCNI'l I.ATloN. ().'] 



US bore on my subject. 1 take this oppoituiiity of again tliaiikiii;^ 

 tliese gentlemen, iind it" 1 have not been able to ineorpoi-ate all that 

 they have so kindly put into my liands at tlie present time, 1 hope 

 tliey will unilei'stand the reason and rest assured tliat I will take the 

 earliest opportunity ot" utilising it in some othei* way. 



2._S0ME RECENT VIEW.S ON THE SUBJECT (3F 

 MINE VENTILATION. 



By AV. CULLKN. 



Prior to the war, the question of ventilation of the mines of the 

 Witwatersrand hardly received that amount of attention which its 

 importance demanded : but perhaps after all that could scarcely be 

 expected, seeing that serious mining to siny depth had onl}' been 

 carried on for about ten years — if indeed so long. In the early daj's 

 the workings were of no great depth, so that the \entilation problem 

 was seldom acute ; but nowadays, when the (jre is drawn from depths 

 of 4000 feet and over, it is becoming increasingly ditficult, but not by 

 any means insurmountable. 



It is a truism to sa}' that the greater the purity of the air under- 

 ground, the better will be the health of the workers. Indeed, it is the 

 terrible mortality amongst both whites and blacks which has directed 

 public attention to the matter, and within the last few years very great 

 progress has to be recorded. In the following notes I propose only to 

 direct attention to one important aspect which has not escaped obser- 

 vation by others, but which still opens up a large field of inquiry. 



The atmosphere of the mines of the Witwatersrand is perhaps as 

 good as, if )iot better than that of any othei* mines of equal depth in 

 the whole world, but in few other places is mining carried on v.ith 

 such intensity. In other words, there are always large numbers of 

 people underground, and to get out the large tjuantities of ore equally 

 large quantities of explosives have to be used. These two factors have 

 an immense intiuence on the mine atmosphere, and it is to them that I 

 propose to direct your attention. Fortunately the question of venti- 

 lation is not greatly complicated by other factors, for there is little 

 so-called ground gas produced : carbonates are seldom met with ; 

 sulphides are only present in small (juantities, and the only organic 

 matter is that introduced by workers. The main contamination, 



