Fort Gratiot in St. Clair County, Michigan — The American Midwest (Great Lakes)
Lake Huron Water Supply Project / Tunnel Explosion
Registered Michigan Historic Site
Photographed By Joel S., September 19, 2015
1. Lake Huron Water Supply Project/Tunnel Explosion Marker
Inscription.
Lake Huron Water Supply Project, also, Tunnel Explosion. Registered Michigan Historic Site.
Lake Huron Water Supply Project. In 1968, to serve the water needs of a growing population, the Detroit Metro Water Department began work on the Lake Huron Water Supply Project. This massive feat involved erecting a submerged intake crib connected to a six-mile intake tunnel beneath Lake Huron. The mechanical mole that dug the 16-foot wide tunnel bored through the bedrock beneath the lake at a rate of 150 feet a day. The project excavated more than one billion pounds of rock. The water treatment plant pumped clean water into an 82-mile system of water mains supplying Detroit and Flint. When finished in 1973, the $123 million system boasted a capacity of 400 million gallons a day.
Tunnel Explosion. On December 11, 1971, a shotgun-like blast claimed the lives of twenty-two men working on a water intake tunnel beneath the bed of Lake Huron. A pocket of methane trapped within a layer of ancient Antrim shale fueled the explosion. An exhaustive inquiry determined that drilling for a vertical ventilation shaft from the lake's surface had released the trapped gas. A drill bit that fell ignited the gas. The blast created a shock wave with a speed of 4,000 miles an hour and a force of 15,000 pounds per square inch. Witnesses reported seeing debris fly 200 feet in the air from the tunnel's entrance. This tragedy resulted in stronger mining safety regulations and enforcement. It was one of the deadliest industrial accidents in Michigan history.
Lake Huron Water Supply Project
In 1968, to serve the water needs of a growing population, the Detroit Metro Water Department began work on the Lake Huron Water Supply Project. This massive feat involved erecting a submerged intake crib connected to a six-mile intake tunnel beneath Lake Huron. The mechanical mole that dug the 16-foot wide tunnel bored through the bedrock beneath the lake at a rate of 150 feet a day. The project excavated more than one billion pounds of rock. The water treatment plant pumped clean water into an 82-mile system of water mains supplying Detroit and Flint. When finished in 1973, the $123 million system boasted a capacity of 400 million gallons a day.
Tunnel Explosion
On December 11, 1971, a shotgun-like blast claimed the lives of twenty-two men working on a water intake tunnel beneath the bed of Lake Huron. A pocket of methane trapped within a layer of ancient Antrim shale fueled the explosion. An exhaustive inquiry determined that drilling for a vertical ventilation shaft from the lake's surface had released the trapped gas. A drill bit that fell ignited the gas. The blast created a shock wave with a speed of 4,000 miles an hour and a force of 15,000 pounds per square inch. Witnesses reported seeing debris fly 200 feet in the air from the tunnel's
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entrance. This tragedy resulted in stronger mining safety regulations and enforcement. It was one of the deadliest industrial accidents in Michigan history.
Erected 2011 by Michigan Historical Commission - Michigan Historical Center. (Marker Number L2219.)
Location. 43° 4.928′ N, 82° 28.201′ W. Marker is in Fort Gratiot, Michigan, in St. Clair County. Marker is on Park Road east of Michigan Highway 25, in the median. The marker is in Fort Gratiot County Park. The entrance to the park is about 0.1 mile east of M-25 on Metcalf Road. The park road is unnamed, but is a loop, with the marker about 0.3 miles into the park. Touch for map. Marker is at or near this postal address: 3325 Lakeshore Road, Fort Gratiot MI 48059, United States of America. Touch for directions.
3. Lake Huron Water Supply Project/Tunnel Explosion Marker
Credits. This page was last revised on June 5, 2022. It was originally submitted on September 24, 2015, by Joel Seewald of Madison Heights, Michigan. This page has been viewed 792 times since then and 42 times this year. Photos:1, 2, 3. submitted on September 24, 2015, by Joel Seewald of Madison Heights, Michigan.