On February 27, 2001, at approximately 1430 mountain standard time, a Eurocopter-France AS-350-B2 helicopter, C-GEYN, operated by Venture Helicopters Ltd., Calgary, Alberta, sustained substantial damage when it collided with a utility box while landing on an snow and ice covered field near Powder River, Wyoming. The commercial pilot and sole occupant on board was not injured. Visual meteorological conditions prevailed and no flight plan had been filed for this local flight being operated under Title 14 CFR Part 91. The flight originated at approximately 1330. According to the pilot, he had just completed a mission repositioning seismic equipment and was landing on a snow and ice covered field in a confined staging area. He locked the collective control lever in the full down position, reduced power to 70 percent and opened the door to see if he had landed on one of his long lines. He inadvertently bumped the cyclic resulting in the helicopter turning to the right approximately 70 degrees allowing the lower vertical fin on the tail boom to come in contact with a metal gear/equipment cage. The structural integrity of the fin was compromised and required replacement.