 In order to minimise the casualties to his brigade , Porter decided to isolate the Pocket with two infantry companies while a heavy artillery barrage was fired into the area over several days . An attempt to capture the Pocket would only be made once it was judged that the Japanese were no longer capable of resisting effectively . As part of this plan , the 2 / 12th Field Regiment eventually fired 140 tons of shells into the Pocket between 15 and 20 June . 
