Miner's Revenge Mountain Bike Race still under construction.

GREENLAND -- While you might expect to see bats on a tour of the Adventure Mine in Greenland, running into a mountain biker would be a surprise.

Rob Peters, chief course designer of the Miner's Revenge Mountain Bike Race, says it's easier than it looks.

The race that is set for Sunday, July 12, might be one of the few races to go underground.  The cost is $25 dollars.  A headlamp is required.

"I figured it would be a little bit looser, a little bit bumpier," said Peters, "and after riding through it, it turned out a little smoother and little bit easier than I thought."

The course, a five-mile loop will run through through the unlit, sometimes narrow, mine adits, where guides give tours in the summer.  At one point, riders will have to get off and push because the ceiling is too low to pass.

"I'm not an experienced mountain biker and I found it passable," said mine owner and organizer, Matt Portfleet.  "It's challenging.  Obviously it's a hard landing if you do fall.  So that's one thing to be aware of."

And the challenge for riders won't end once they leave the adit.  Course designers decided to use the natural landscape to make the ride difficult, like the two mountains on the property.

"It's going to be one of the more difficult courses just due to the steep climbs that we have around here," Peters said.  "But it's nothing you can't climb up and just walk the bike with you."

Racers will also see old mine buildings along the way as the course weaves through broken stone walls and doorways.

Bike organizations and news agencies from around the country have contacted mine owners, expressing interest in the race.

"We had a radio interview from Washington, D.C. about two weeks ago," Portfleet said.  "They called and wanted some information on the race."

Originally they expected 50 racers to compete, but now they're thinking over 100.