LJR
Member
Sorry for the late reply, I am abroad on hols at present and missed things. However, I have still been exploring. Did anyone see the Aditnow Facebook post about the iron mine in France near Nancy? We went last week, interesting place.
Bad air in mines is a fascinating subject. Over the years (50 of ‘em) that I have been facing such problems, I have found that each case is unique. You can generalise a bit but you must not assume anything.
We re-opened a decline in North Lincolnshire, next to a railway line. We descended about 200 yards to a fall. Air fine to this point. The fall was about 6 feet high in a roadway of maybe 20 feet arch section. Up and over the pile and into a lake of bad air. Hold the meter up and all is fine lower to knee level and we all die. Cure - install a small extractor fan on another entrance and come back 18 months later and all is fine.
Generally methane is produced when ground is cut. Old coal mines do not usually present methane as a problem, it is bad air that causes the trouble.
We descended Mawstone mine (lead) and found methane still issuing at the shaft bottom. We ventilated with fan and loads of ducting to try and get to where the explosion happened in 1936. As we went inbye the air got worse with 2% methane in the general body after 60 years!
Treat each mine as a new experience and test everything until you get to know the normal for that particular site. Don’t underestimate the power of atmospheric pressure, on a large iron mine it can have a huge effect on the air. It can overcome forced ventilation at especially bad times.
In the olden days, coal mines were given a heads up by the Met Office if there was to be a pressure drop of more than a certain amount in a short period (can’t remember the amount, sorry) so that Deputies could be warned to look out for gas expanding out of waste areas and flooding working areas.
Bad air in mines is a fascinating subject. Over the years (50 of ‘em) that I have been facing such problems, I have found that each case is unique. You can generalise a bit but you must not assume anything.
We re-opened a decline in North Lincolnshire, next to a railway line. We descended about 200 yards to a fall. Air fine to this point. The fall was about 6 feet high in a roadway of maybe 20 feet arch section. Up and over the pile and into a lake of bad air. Hold the meter up and all is fine lower to knee level and we all die. Cure - install a small extractor fan on another entrance and come back 18 months later and all is fine.
Generally methane is produced when ground is cut. Old coal mines do not usually present methane as a problem, it is bad air that causes the trouble.
We descended Mawstone mine (lead) and found methane still issuing at the shaft bottom. We ventilated with fan and loads of ducting to try and get to where the explosion happened in 1936. As we went inbye the air got worse with 2% methane in the general body after 60 years!
Treat each mine as a new experience and test everything until you get to know the normal for that particular site. Don’t underestimate the power of atmospheric pressure, on a large iron mine it can have a huge effect on the air. It can overcome forced ventilation at especially bad times.
In the olden days, coal mines were given a heads up by the Met Office if there was to be a pressure drop of more than a certain amount in a short period (can’t remember the amount, sorry) so that Deputies could be warned to look out for gas expanding out of waste areas and flooding working areas.