Re: Mine Safety Subordinated to Mining Company Interests

In article <11rvthb931b9223@xxxxxxxxxxxxxxxxxx>, Jo Schaper wrote:
> Interesting, since what I was referring to was first prototyped in 1987,
> and first manufactured commercially in the 1990s. These are chemical
> 'scrubber' rebreathers used by cave divers and originally engineered by
> Bill Stone.
>
Jo, check your caving history. Re-breathers were in use for cave
diving exploration in the late 1940s and 1950s. Indeed, they were the main
equipment used in Britain until about 1960. They were developed in WW2 for
'frogman' applications. Their advantages (long duration, no bubble stream
to stir down silt from the ceiling) were sufficient to offset their
disadvantages (10m working depth limit ; nitrogen purging time ; the joys
of drinking a 'cocktail' if you got water into your absorbent cylinder ;
cantankerous equipment). Bill Stone is well aware of this history - when he
was working on his first rebreathers he was also working with Martyn Farr
on the (a ?) Wakulla project while Farr was working on his definitive "The
Darkness Beckons", and Stone was a significant source of Farr's.
I'm trying to remember when I was first put through the Draeger
course for an oxygen-generating fire-safety re-breather ... I certainly
used them in 1994, and I think I'd met them several years before that.
That's not a stored-gas device (IIRC, permanganate decomposition
accelerated by the heat and moisture of re-breathed air ; the manufacturers
are less than forthcoming ; there's a caustic CO2 absorbent in there too)
because of the requirement for regular re-testing of the cylinders and the
risk of them rupturing in fires.

While John's obviously got some issues with the "MHSA", he's not
being implausible with his technology description.

--
Aidan Karley FGS
Aberdeen, Scotland,
Location: 57°10'11" N, 02°08'43" W (sub-tropical Aberdeen), 0.021233

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