On Thursday, May 09, 2019 08:32:46 AM rhkramer@... wrote:
Works a treat, holds up mountains! ;-) (Well, at least in drift mines --
in deep mines it holds up the earth's surface ;-)
Well, I guess I should / could go a little further -- they do hold up
mountains (or the earth's surface) until you do either longwalling or
pillaring at which time you intentionally want the mountain (or earth's
surface) to collapse ;-) (to relieve the pressure on the remaining pillars).
(Aside: Usually the collapse doesn't have much effect at the earth's surface,
depending on how deep the mine is.)
