Tommyknockers of Maryland Gold Mines A type of spirit linked to mining, Potomac’s tommyknocker sprang from a deadly explosion in 1906 at the now-abandoned Maryland gold mine located near the entrance of the C&O Canal’s Great Falls Tavern Visitor Center. Early last century, Montgomery county, Maryland had over 28 gold mines. Wander the woods off … Continue reading Tommyknockers of Maryland Gold Mines