mat packs

mat packs

[′mat ‚paks]
(mining engineering)
Timbers laid side by side into a solid mass 2 by 2½ feet (61 by 76 centimeters) square and 4-6 inches (10-15 centimeters) thick, kept together by wires through holes drilled through the edges of the mass, carried into a mine and built up to make effective roof supports.