EE was changing C-1 belt in the primary crusher pit. He attached a 1.5 ton chain hoist to a I beam to raise the new belt. The hook on the chain hoist was positioned on the I beam at an angle. When the mechanic pulled the slack out of the hoist, the head of the hoist turned allowing hoist to fall hitting EE in head & face. He sustained 2 cuts on upper lip requiring 5 sutures.