Despite pleas from area landowners, state leaders on Thursday approved underground mineral exploration on 22,000 acres of mostly wilderness land between Ely and Lake Superior.

The unanimous vote came after more than an hour of emotional testimony from residents who had traveled 250 miles to the Capitol in hopes of a better outcome.

Some residents teared up during testimony, one muttered "joke" as state officials explained their rationale for supporting the leases and another resident slammed a baseball in front of the governor and demanded a "fair game."

"This could be devastating," said Steve Brodigan, who owns a hand-built cabin on about 40 acres in the area.

For more than a year, mineral exploration companies have sought leases to explore for nickel and copper on vast tracks of mostly government-owned land in the area. Roughly 100 private landowners tried to get the state to only sell the leases on government owned land.

Many of the landowners have owned their property for decades, but either didn't know or didn't understand that the state owned the mineral rights beneath their land. With soaring demand for cell phones and laptop computers that require the lucrative minerals, mining companies are broadening the exploration in hopes of future riches. State proceeds for the leases and its take from any eventual mining helps pay for public schools.

DFL Gov. Mark Dayton, who serves on the little-known Minnesota Executive Council, said that for more than 100 years state law has required officials to grant of mineral leases. It remains far from certain the exploration will result in any new mining.

"I don't have the legal authority to say, 'Now we should try something different,'" Dayton said before the vote. "The law doesn't give us any leeway in that regard."