During its boom, Picher's population peaked at 20,000. Saloons and movie parlors lined the streets.
But the mines closed around 1970, and the town never fully recovered.
In the 1990s, a study found elevated blood lead levels in Tar Creek-area children, and teachers began noticing years ago that students were learning more slowly and couldn't focus.
In 2006, a U.S. Army Corps of Engineers study found more than 100 homes in Picher were in danger of collapsing into old mines.
Last spring, just weeks after residents gathered to mark the town's final days with a parade, a massive tornado tore through the area, killing six people.
A federal buyout has hastened the town's closure.
For Barr, next month's graduation will be bittersweet, as the school that was once the focus of the small community closes its doors for good.
"Any time an era ends for people who've graduated from a school, it leaves a void somewhat in their hearts," he said. "It's difficult."
Copyright 2009 The Associated Press.