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Fort Gratiot in Saint Clair County, Michigan — The American Midwest (Great Lakes)
 

Lake Huron Water Supply Project/Tunnel Explosion

 
 
Lake Huron Water Supply Project/Tunnel Explosion Marker image. Click for full size.
By Joel S., September 19, 2015
1. Lake Huron Water Supply Project/Tunnel Explosion Marker
Inscription.
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
Lake Huron Water Supply Project/Tunnel Explosion Marker image. Click for full size.
By Joel S., September 19, 2015
2. Lake Huron Water Supply Project/Tunnel Explosion Marker
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.)
 
Marker series. This marker is included in the Michigan Historical Commission marker series.
 
Location. 43° 4.928′ N, 82° 28.201′ W. Marker is in Fort Gratiot, Michigan, in Saint Clair County. Marker is on Park Road east of Michigan Highway 25, in the median. Touch for map. 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. Marker is at or near this postal address: 3325 Lakeshore Road, Fort Gratiot MI 48059, United States of America.
 
Other nearby markers. At least 8 other markers are within 6 miles of this marker, measured as the crow flies. The 1971 Water Tunnel Explosion Memorial (here, next to this marker); Seeing the Light (approx. 5.7 miles away); Fort Gratiot Light (approx. 5.7 miles away); The Storm (approx. 5.7 miles away); Learning from Lake Huron
Lake Huron Water Supply Project/Tunnel Explosion Marker image. Click for full size.
By Joel S., September 19, 2015
3. Lake Huron Water Supply Project/Tunnel Explosion Marker
(approx. 5.7 miles away); Sending a Signal (approx. 5.7 miles away); Keepers Duties (approx. 5.7 miles away); a different marker also named Fort Gratiot Light (approx. 5.8 miles away).
 
Also see . . .
1. Remembering Those Who Died. Account of the tragedy from the Detroit Water and Sewerage Department. (Submitted on September 24, 2015, by Joel Seewald of Madison Heights, Michigan.) 

2. Port Huron, MI Water Tunnel Explosion, Dec 1971. Report from the Benton Harbor newspaper, The News Palladium, that includes an interview with a former safety inspector on the tunnel project. (Submitted on September 24, 2015, by Joel Seewald of Madison Heights, Michigan.) 
 
Categories. DisastersMan-Made Features
 
 
Credits. This page was last revised on June 16, 2016. This page originally submitted on September 24, 2015, by Joel Seewald of Madison Heights, Michigan. This page has been viewed 252 times since then and 64 times this year. Photos:   1, 2, 3. submitted on September 24, 2015, by Joel Seewald of Madison Heights, Michigan.
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