plug-and-feather method

plug-and-feather method

[¦pləg ən ′feth·ər ‚meth·əd]
(mining engineering)
A method of breaking large quarry stones into smaller blocks; a row of holes is drilled in the stone along a line where the break is desired; a pair of feathers (semicircular cross-section rods) is inserted in each hole; a plug (steel wedge) is inserted between each feather pair; the plugs are hammered in succession until the stone fractures.