Hanson Material Service and the Metropolitan Water Reclamation District of Greater Chicago (MWRD) recently celebrated the “Last Blast” removing the final 36,000 tons (32,659 t) of rock from the southwest corner of the reservoir being created at the Thornton Quarry in Thornton, Ill., south of Chicago.
On hand were many local dignitaries and representatives from groups with a stake in the success of the MWRD’s project to protect the waters and communities of Chicago and surrounding suburbs.
“During the past 15 years, 76 million tons of dolomite stone have been removed from this north lobe of the Thornton Quarry,” Jeff Brasuell, Hanson Material Service’s area operations manager, said during the ceremony.
This quarry project is one of many mine reclamation and sustainability projects undertaken by Hanson, which include the old Sterns Quarry in Bridgeport, now a public park offering area residents varied recreational opportunities.
Edward Paesel, executive director of the South Suburban Mayors and Managers Association, said he was pleased the reservoir will help easy flooding in local communities. “This is recycling and reusing at its best,” Paesel said.
Thornton Composite Reservoir is an important part of the MWRD’s Tunnel and Reservoir Plan (TARP), which is designed to improve water quality and prevent flooding caused by combined sewer overflows. TARP, also known as the “Deep Tunnel,” is a huge project, now in its 15th year, consisting of more than 100 mi. (161 km) of tunnels deep below the surface of the Chicago region and three reservoirs designed to capture and hold stormwater and combined sewage for treatment at water reclamation plants.
Combined sewers, present in many older cities like Chicago, receive water from the drains in homes, businesses, and storm drains on streets.
They can quickly become overwhelmed during heavy rains and are designed to overflow into waterways. TARP is being built to eliminate these combined sewer overflows and resulting pollution by capturing the excess stormwater and sewage in a reservoir until it can be treated.
John Lemon, principal engineer of MWRD, led a tour of the quarry floor and highlighted ongoing work at Thornton Quarry.
“We’ve recently completed one of the largest dams in Illinois which now separates the reservoir from the active mining operations at the quarry,” he said. Cement will be injected into 350 to 500 ft. (107 to 152 m) deep holes around the perimeter of the 350 ft. (107 m) deep north lobe of the quarry which ensures up to 7.9 billion gal. (29.9 billion L) of water stays inside the reservoir until it can be treated.
Contractors for the MWRD are finishing connecting tunnels to the Thornton Composite Reservoir. Work is on schedule to be completed by 2015. The reservoir will be part of the Calumet TARP tunnel system protecting 182,000 structures while serving 556,000 people in 14 communities throughout the south side of Chicago and south suburbs of Cook County, and will help protect water quality in the Calumet Rivers and Calumet-Sag Channel.
“This is one of the most visionary projects in our history,” said MWRD executive director David St. Pierre. “This is no small plan!”
The Thornton Composite Reservoir will be utilized alongside a similar reservoir in the early stages of construction at the Vulcan Materials Company’s McCook Quarry. TARP will ultimately combine three reservoirs, including the Majewski reservoir, providing 20.5 billion gal. (77.6 billion L) of storage capacity serving four million people living and working in a 352 sq. mi. area in and around Chicago.
For more information, visit www.mwrd.org.