ARTIST: Robert Smithson ART: Spiral Jetty DATE: 1970 MATERIALS: 1,500-foot-long, black basalt coil. LOCATION: Salt Lake, Utah (Rozel Point) In April 1970, two dump trucks, a tractor, and a front loader began moving the 6,650 tons of rock and earth needed to create Spiral Jetty. A film crew recorded the venture, and Smithson directed rock placement to the workers. Despite how disruptive this process sounds, the Spiral Jetty now seems at home in this vast, deafly quiet la