Hi, I am just wondering about ventilation requirements in Canada. I read that you require 100cfm per diesel HP of equipment in a single circuit - but what does a single circuit mean?

I basically want to know if your total cfm entering the mine must provide for the sum of all simultaneously operating headings, or if it can be reused on each heading to provide each heading with supple used air as long as gases limits are not reached.

If it is the former case, is it in writing anywhere legitimate?

  Basically the answer is yes in all cases.  Yes you can re use the air but you have to maintain the 100 cfm / hp formula at every location where diesel equipment is in use.  Each development heading,  with say 300 operating HP requires 30,000 cfm but if you have three such headings in an area developed off a ramp , you need  90,000 cfm in the ramp and if the theoretical mine had two ramps in parallel, exhausting thru a single vent raise,  you need 180,000 cfm total to feed the  1800 operating HP.

The details and actual rules vary by province,  but seek out either British Columbia or Ontario Mines Regs.


Other factors do come into play  and the 100cfm / hp becomes an effective minimum.   

Fantastic, that is what I though. I was in an argument with my employer and they seemed to think that if you had a mine with say 60 000cfm total fresh air intake, you could reuse that air to any extent and as long as auxiliary ventilation was sufficient, you could even have a single heading with more than 600HP.

I guess it is time to get a new employer!

Thanks a ton for your response.