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Dec 27, 2009, 9:40am

Coal, Colliery and Mining Forum. :: Mining Methods and Geology. :: Bord and Pillar Methods. :: Board & Pillar?

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Topic: Board & Pillar? (Read 1,978 times)

Ragger
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Board & Pillar?
« Thread Started on Feb 4, 2005, 11:05am »

(a) board and pillar
(b) pillar and stall
(c) room and pillar
(d) stoop and room.

The name varied depending upon the part of the country the mining took place, however the method was basically the same.

Anyone know of any other names.

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dazb
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Re: Board & Pillar?
« Reply #1 on Feb 4, 2005, 11:34am »

Bord and pillar, (same as board I guess),
Post and Stall,
Stall Worked,
and here is one up for grabs, for some reason I cannot shake off the thought that I recall this method being referred to as Pillar and Post locally at least, I know that it seems to be nonsensical by virtue of both terms being support methods, but we are a queer lot in this corner anyway (tail-gate corner that is, probably all the dust that causes it)

« Last Edit: Feb 4, 2005, 11:38am by dazb »

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John
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Re: Board & Pillar?
« Reply #2 on Feb 4, 2005, 4:27pm »

I knew of the names, but the two hard rock mines I worked in, in the UK it was Bord and Pillar, same in the coal mines I worked in down under.
Pillar dimensions varied with the depth and pillars according to strata loading. All but one mine used roof bolts and w straps. British Gypsum were the exception due to the low roof cover and strength of the rock strata forming the overburden.

Roof creep was another problem in deeper mines, at Boulby, being three quarter of a mile from the surface, they used to leave a curved piece from the rib to the roof. That all stopped with the introduction of continuous miners.
The conveyor road outside the control room "crept" from around fifteen feet in height down to less than six feet in around three years. It was backripped, bolted and steel arches set. CPL's site gives the amount of creep expected yearly on main roads.

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kabelo
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Re: Board & Pillar?
« Reply #3 on Aug 14, 2005, 6:08am »

Hi there,

What is the correlation between pillar size and depth. would there be a simple table perhaps that one could access showing this relationship, specifically for the Bushveld Igneous Complex in South Africa?

Regards,
Kabelo

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John
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Re: Board & Pillar?
« Reply #4 on Aug 14, 2005, 8:20am »

Pillar width, length and bord width are worked out according to geology, ie, seam stresses and seam depth. Rock mechanics and the Mine Manager work those out according to local conditions, ie depth from the surface and type of mineral.
When I worked at BG's East Leake mine, Marblaegis, roads were seven yards wide, pillars were uniform at seven yards square, depth of cover, anywhere from a couple of hundred feet to tens of feet.
Boulby mine on the other hand was three quarter of a mile depth of cover with a mineral that allowed "creep" . Hence the pillars were on the large size, long and fairly wide with narrow entries.
Coal in the NSW coalfield, we used uniform square pillars and entries were approx 20 feet wide.
There are loads of factors to take into consideration. Maybe we have a mining engineer who is a member who can answer you question better than myself.

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