A FALL OF ROOF OCCURRED AT THE TAILGATE OF 3T LONGWALK IN 3 AC OF 25 @ 89 + 20. USING 8'RIB BOLTS FOR TRUSSES AND 6' COMBINATION DOUBLE FORK IN CENTER AND 2 ROWS OF 6X6 TIMBERS BETWEEN XC'S. SLIP RUNS THROUGH AREA LOST POWER ON FACE COULD NOT PULL SHIELDS AND LOST THE ROOF.