Retreat mining in the #5 entry pillar block when the roof started working in the previously mined #4 entry block. The roof fell in the #4 entry and took out the breaker timbers. The timbers were replaced and mining continued. The roof began working again, mining ceased. The roof in the #4 entry fell again, the fall maesured approx. 80'L x 22'W x 5'H. The entry was timbered off.