AT 8:30PM APPROX 2 TONS OF FINES WAS SPILLED FROM THE 2600 SKIP POCKET. EMPLOYEE STATED HE CLOSED THE BACK GATE, THE FRONT GATE OPENED. ALL COMPARTMENTS WERE INSPECTED AND MINIMAL DAMAGE OCCUR RED. SPOOL VALVES FUNCTIONING PROPERLY WHEN INSPECTED. CLEARED AT 1:15 PM. REPORTED TO MSHA AT 8:15 AM ON 3-29.