EMPLOYEE WAS HELPING TO CARRY A 7'X16""X1/4"" METAL PLATE INTO THE TUNNEL TO REPAIR SIDE SKIRTS ON FEEDER BOX. EMPLOYEE SLIPPED ON LOOSE GRAVEL AND CAUGHT RIGHT MIDDLE FINGER BETWEEN THE METAL P LATE AND GRAVEL. FINGER WAS LACERATED, REQUIRING SUTURES. EMPLOYEE WEARING GLOVES AT THE TIME OF THE INCIDENT.