Arch
Arch
A portion of rock left standing at the intersection of a mine wall and roof, to support the roof.
Curved roof of underground opening
A curved structural member used to span openings or recesses; also built flat. Structurally, an arch is a piece or assemblage of pieces so arranged over an opening that the supported load is resolved into pressures on the side supports and practically normal to their faces.
One of the five chambers of a brick kiln; also, the fire chamber in certain kinds of furnaces and ovens.
The roof of a reverberatory furnace.