Drop in behind the picnic table at the Bobletts Gap parking lot onto a short trail that takes you to Boblett's Gap fireroad, also known as Chair Rock Road. Turn right, dropping down exactly 1 mile on a sometimes rocky, sometimes water-holed blast of a 5% downhill.
The singletrack is a hard right that cuts back, and straight up. Keep a close eye out, as the trail is hard to see following a left hand sweeper. Watch your odometer too, more than 1 mile exactly and you missed it. Mineshaft starts as a short, steep 25%+ gradient before reaching the shelf trail that becomes much more reasonable.
For 5 miles, enjoy a singletrack experience like no other, passing iron ore hollers with mineshafts and holes visible when you hike up the ore piles in certain crevasses of ancient Appalachian mountains.