The IE felt a piece of coal/stone hit L.hand from an elevation while hoisting a new siding panel with a rope & pulley. Prior to removing the old siding, the floors were cleaned near the panels to be removed. Not certain how/from where it fell. The whole bldg vibrates and there is a lot of area. Non-displaced transverse fracture of the 1st metacarpal. Restricted duty 4-6 weeks.