Operator of (ULD59) was remote mucking a floor pull in the 4430-141. The mucker was 100 feet from the operator when the left rib began to work, trapping ULD59. MSHA 800 line was called. EE of MSHA placed a (k)order on potentially affected areas yet said we over reported. MSHA supervisor EE advised that a 7000-1 still needed to be filed.