The safety lamps prevented explosions from which gas? and the canaries indicated the presence of the same or another gas?

Safety lamps – methane.
Canaries – carbon dioxide and/or carbon monoxide

Geoff D, thankyou

What % of CO2 in the air will snuff out a candle flame? Or what % of O2 is required to sustain a candle flame?

A burning candle will draw available O to it.

A canary will do the same.. as too will a human..

when each of the above runs out of enough % of O.. they all extinguish.

>>when each of the above runs out of enough % of O.. they all extinguish.

Yes but what is the % figure please roughy?

bob(from black rock) said:

>>when each of the above runs out of enough % of O.. they all extinguish.

Yes but what is the % figure please roughy?

Depends on the situation an which gases are present. Plus other things ie: whether you are crouched down or standing up, halfway up the ladder.. working or not working.. but I can dig the ground I’m in a fair way due to the fact that there may or may not be air coming in from drive dug in the initial opal digging frenzy.. but in virgin ground I’d say that you cannot get far away – up a drive – from the bottom of a 10m deep shaft without providing ventilation in some way or other.

CO2 concentrations; 10% approx to asphyxiate a human, 40% to extinguish a flame. Clearly, less than 10% to shuffle a canary off its mortal coil.

Thanks, Geoff D

Whoops – extinguishers try to up the conc to 40%. 10% in still air will also extinguish a flame as well as threaten a human. So if a candle was used to warn of CO2 in a mine, once it went out the miners would also be feeling groggy.

roughbarked said:

bob(from black rock) said:

>>when each of the above runs out of enough % of O.. they all extinguish.

Yes but what is the % figure please roughy?

Depends on the situation an which gases are present. Plus other things ie: whether you are crouched down or standing up, halfway up the ladder.. working or not working.. but I can dig the ground I’m in a fair way due to the fact that there may or may not be air coming in from drive dug in the initial opal digging frenzy.. but in virgin ground I’d say that you cannot get far away – up a drive – from the bottom of a 10m deep shaft without providing ventilation in some way or other.

As I said, I do have possible ventilation.. I always check this out.. In most of my situational mining experience.. I can be so hot while working as to require removal of all clothing including such as safety helmet and goggles.. Stop for a few seconds and the breeze coming through from old drives.. causes me to put all clothing back on plus maybe a jacket.

If I don’t notice this.. I will have to provide my own ventilation as @ 6 to 10 m deep.. air is difficult to recirculate.. Physically working.. sending up buckets of mullock etc.. do help circulate air.. fans are useful.. in the old days they set up wind socks but in general since they were at a time reduced to 12 sq ft..claim size.. most shafts arent too far away from fresh air.. if you can read the surrounding diggings.

Geoff D said:

Whoops – extinguishers try to up the conc to 40%. 10% in still air will also extinguish a flame as well as threaten a human. So if a candle was used to warn of CO2 in a mine, once it went out the miners would also be feeling groggy.

It flickers before that.

there will be blood

wookiemeister said:

there will be blood

There definitely is if you bump the walls with your hand gloved or not, while jackhammering.

Basicaly what I am saying.. is that there is a depth at which you can no longer dig downwards without forcing air down to you. As there is also a distance away from the main shaft you can travel without needing a ventilation shaft or other method of supplying refreshed air

see.. no edit button so I cannot fix error..

sure it is barefaced and all that.. so it has advantages and many sniping points. Maybe on a larger post I would type it up in a text app..