This article has a nice photograph of supports being installed.
Those supports are active - they move forward as the coal is being cut. They have something called a "Chock Control Interface" (it's the smallish box, at knee hight, on the hydrolic arm, with the big thick cables attached.)
I used to build and test those boxes. I was part of a sub-contract firm, the client was Dowty Mining, then Longwall, then Joy Mining. They were fun to build - you used a variety of different engineering.
Seeing that photo gave me a bit of a flashback.
EDIT: This article mentions a radio programme, but does not link to it. The BBC iPlayer makes it hard to find the programme the article talks about.
Those supports are active - they move forward as the coal is being cut. They have something called a "Chock Control Interface" (it's the smallish box, at knee hight, on the hydrolic arm, with the big thick cables attached.)
I used to build and test those boxes. I was part of a sub-contract firm, the client was Dowty Mining, then Longwall, then Joy Mining. They were fun to build - you used a variety of different engineering.
Seeing that photo gave me a bit of a flashback.
EDIT: This article mentions a radio programme, but does not link to it. The BBC iPlayer makes it hard to find the programme the article talks about.
Here are some about coal mining (including "The Light", the programme talked about): http://www.bbc.co.uk/radio4/collections/p02t6qzd
(One of those mentions the Forest of Dean, which is where one of the Stack Exchange devs is from.)
and here's a direct link to The Light: http://www.bbc.co.uk/programmes/b05y4f96
And here's another programme from that author about growing up poor: http://www.bbc.co.uk/programmes/b01nzqvr