Scuba Diving at Bonne Terre Mine

Located about 60 miles south of St. Louis, Missouri is one of the best inland sites for scuba diving in America, the Bonne Terre Mine. A lead mine dating to before the Civil War and shut down in 1961, much of Bonne Terre is flooded and these parts are now the "Billion Gallon Lake," essentially a man-made freshwater cave that constitutes what is considered by many experts to be the largest freshwater scuba resort in the world. It also offers divers without specialized training an entry into the exhilarating world of cave diving.

Bonne Terre Mine has 24 established "dive trails" within it, and since dive trips within the mine are normally held only on Fridays, Saturdays and Sundays, a diver would need two months to explore the entire mine. Like a natural cave dive, the water in the Bonne Terre Mine rivals the tropics for crystal clarity, with visibility routinely in the 100-foot range. Unlike a natural cave, the floor of the mine does not have a thick layer of sediment, so in many places the shafts of the Bonne Terre mine have substantially less risk of a diver making a mistake and stirring up a thick cloud of silt, thereby causing a black out. This is one of the incidental, yet important safety elements that make Bonne Terre a safe way for a normal recreational diver to explore the world of cave diving. Adding to the safety is the 600,000-watt lighting system, providing ample light for most of the mine network.

As an exercise in "deep earth diving," Bonne Terre Mine shares many features in common with caving. The water temperature in the mine is always 58 degrees Fahrenheit. Chilly temperatures like that demand either a drysuit or the thickest of wetsuits, and divers who do not normally dive with such an exposure outfit will need to conduct a thorough buoyancy check before setting out. Also, just because the Bonne Terre Mine offers a reasonably controlled introduction to the cave diving environment does not mean diving there does not require a full set of gear. A diver should have two dive lights, at least one dive knife or pair of sheers, and a helmet would not be a bad idea either.

Bonne Terre Mine is a dive shop and school as well as a resort, so rental gear and classes are available. The resort operates on a two-dive minimum basis, and offers room-and-dive packages in the Inn and Depot Bed and Breakfast or the bunkhouse Park and Allen Divers Lodge. For non-divers, the mine has walking tours of the dry parts of the mine, as well as a boat tour of some parts of the mine. The town of Bonne Terre is also home to a roadside attraction-style Space Museum.