SPOKANE, Wash. (AP) — Workers this weekend finished installing a protective cover over a partially-collapsed tunnel that contained radioactive waste on the Hanford Nuclear Reservation, the U.S. Department of Energy said Monday. The tunnel that contained highly radioactive wastes left over from production of plutonium for nuclear weapons partially collapsed on May 9, prompting evacuation of nearby workers. The hole left by the partial collapse was filled with more than 50 truckloads of soil the next day. The Energy Department has said no workers were injured and no airborne radiation escaped into the environment as a result of the incident.