This image gives a comparative indication at just how big the excavation of the mine is. What is pictured here on the mine wall is an unplanned movement of the stepped ridges. Although rare, such movements do occur, however, because of Kennecott's safe and efficient mining practices, ongoing training of its work force, state-of-the-art geological monitoring equipment, zero tolerance safety programs, practices and requirements, such occurrences are prepared for and safely handled. Kennecott's safety record is among the best in the industry.