The commercial helicopter pilot was positioning the helicopter to move crew members from a drilling test site. As he approached and passed the approximately 70-foot high drill tower, he related that he was about 30 feet above the ground, when he heard a violent bang and lost control of the helicopter. The helicopter immediately became uncontrollable, and descended rapidly to the ground, where it caught fire. The pilot said he was able to release his seat restraints, and crawled through where the windscreen/bubble used to be. The drilling crew had previously stripped approximately 6,000 feet of 3/8-inch thick cable from the drum at the base of the drill tower, over the top of the tower, and onto the ground. The pilot was unaware of these activities, and did not see the wire until after he had collided with it. According to the operator, pulling the wire off the drum was a rare occurrence, and there was no active communication from ground personnel alerting the pilot that the wire was trailing away from the tower.