Report - Cononley Lead Mine - 03/09/17

[pirate]

You didn’t read CC’s post........he didn’t deny rotting props cause methane just not in the amount needed (5-15%)in volume to cause firedamp

 

[JoanneCard?]

"Wet wood without any air circulating can cause firedampt" is the comment I was pulled up on and something that is very possible. The speed of the decay and the confinements around it are what could possibly create the percentage in the area around the wood.

Baryte, (Barium oxide), a major mineral in Cononley, is permeable and would soak up these gasses and disperse them effectively unless totally saturated.

I've tried looking for the report where is says the air was bad possibly due to the rotting pit props and we made a hasty retreat and what their gas meter was reading...
but I've not found it yet... I will, but I'm not going to get all compulsive over it but I'm pretty sure it was for methane ...
TBC

 

[cunningcorgi]

"Wet wood without any air circulating can cause firedampt" is the comment I was pulled up

Joanne

You weren't 'pulled up' on this comment. My reply was actually -

'More likely to be blackdamp - a mixture of carbon dioxide, water, nitrogen and other shit that replaces oxygen - from rotting wood in unventilated areas.

Nasty fucker.'

It didn't say you were wrong, it didn't diss you, it didn't try and make you look a fool, etc. It simply said that what you described, in the type of mine you described and in the conditions you described meant that any bad air you might encounter would more likely to be blackdamp and not firedamp.

There is no general rule / one glove fits all scenarios for the air you encounter in different types of mine. A lead mine is different to a gold mine which is different to a coal mine which is different to a stone mine, etc. (the same sort of mines, coal as an example, can have completely different types of air too - see Forest v South Wales mines with regard to safety lamp use).

Methane can be produced in ANY mine...it is the quantities it is produced in that matters. And in a de-watered metal mine, these quantities should not be at a level to produce firedamp (5-15% of air volume).

As for gas meters, most 4 gas are calibrated to LEL so a reading of 10% for LEL does not mean that you are in an atmosphere with 10% methane in the air (the most explosive limit). It means you have reached 10% of the LEL which is usually 5% (depending on calibrating gas) or in other words, 0.5% of methane in the air by volume. If the meter was showing a reading of 80% LEL then there still would only be 4% methane in the air by volume.

It is great that you are looking at mines (everyone should IMO !) but it is also good to know everything that can be encountered and how to notice it. Your life might depend on it someday.

 

[OrchardLeaf]

To complicate matters slightly coal _was_ encountered in Cononley Lead Mine, intersecting the Deep Adit level in the workings around Hope Shaft (described as a 15 inch seam in the workings north of Weasel Green in old documents), half a mile or so north west from Engine Shaft and the engine house. Flat rods were extended across the valley from the engine to Hope Shaft in order to pump water out of workings below the Deep Adit).

There is no record of the coal being worked but there could be some gases associated with it. I think I read that Hope Shaft was capped with concrete so I don't know how well ventilated that area would be (and it is at the western extremities of the mine) the area around it looks a bit overgrown so I haven't looked there. A horse whim was used for winding in Hope Shaft and the horse circle apparently was still visible a few metres to the west of the shaft in 1987, I may go for a look to see what can be seen at some point.

Barytes or Barite which the mine was worked for in its later years is Barium Sulphate (not Barium Oxide from what I can see) is insoluble, hence its use in Barium meals (Barium usually being as poisonous as lead).