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![Thornton Construction in progress](/sites/default/files/styles/project_hero/public/2023-12/Photo%20for%20Website_%20Thornton%20Connecting%20Tunnels%20and%20Shaft%232.jpg?itok=V2fgT6Hi)
![Thornton Connecting Tunnel & Gates](/sites/default/files/styles/project_hero/public/Connecting%20Tunnels%20and%20Gates%2C%20Thornton%20Composite%20Reservoir_Carousel.jpg?h=418bbcf4&itok=0YfmopRO)
![Thornton Connecting Tunnel & Gates](/sites/default/files/styles/project_hero/public/Connecting%20Tunnels%20and%20Gates%2C%20Thornton%20Composite%20Reservoir_Carousel1.jpg?h=418bbcf4&itok=YxX8L6ud)
![Thornton Connecting Tunnel & Gates](/sites/default/files/styles/project_hero/public/Connecting%20Tunnels%20and%20Gates%2C%20Thornton%20Composite%20Reservoir_Hero.jpg?h=da6cf0c2&itok=SLApLjfb)
Thornton Connecting Tunnel & Gates establishes connections between the existing underground water system and the Thornton Quarry through the construction of connecting tunnels and a gate shaft. The Thornton Quarry serves as a temporary holding reservoir for wastewater before undergoing treatment and eventual release into Lake Michigan.
The project was executed in two distinct phases. In Phase One, which spanned 18 months, a series of critical tasks were successfully completed. This included the excavation of a 63-foot-diameter shaft through a layer of common overburden measuring 14 feet in thickness. Additionally, drill and blast excavation was performed over a length of 335 feet through hard rock. Phase One also encompassed the drill and blast excavation of a bifurcation chamber, measuring 215 linear feet with dimensions of 60 feet in width and 40 feet in height. 970 linear feet of a 33-foot-diameter horseshoe drift were excavated. To ensure structural integrity, the excavation was reinforced using a combination of resin-grouted dowels, rock bolts, and fiber-reinforced shotcrete.
During the second phase of the project, the focus shifted to the drill and blast excavation of a tunnel connection, measuring 50 feet by 33 feet in diameter. Additionally, 70 feet of reinforced concrete lining with a diameter of 30 feet were installed. Access to Phase Two was facilitated through an existing shaft, measuring 340 feet in depth and 30 feet in diameter.
![Thornton Connecting Tunnel & Gates](/sites/default/files/styles/gallery_image/public/Connecting%20Tunnels%20and%20Gates%2C%20Thornton%20Composite%20Reservoir_Carousel.jpg?h=418bbcf4&itok=CIgGi2UU)
![Thornton Connecting Tunnel & Gates](/sites/default/files/styles/gallery_image/public/Connecting%20Tunnels%20and%20Gates%2C%20Thornton%20Composite%20Reservoir_Carousel1.jpg?h=418bbcf4&itok=jPkRJegZ)
![Thornton Connecting Tunnel & Gates](/sites/default/files/styles/gallery_image/public/Connecting%20Tunnels%20and%20Gates%2C%20Thornton%20Composite%20Reservoir_Carousel3.jpg?h=418bbcf4&itok=GaakqW54)
![Thornton Connecting Tunnel & Gates](/sites/default/files/styles/gallery_image/public/Connecting%20Tunnels%20and%20Gates%2C%20Thornton%20Composite%20Reservoir_Carousel4.jpg?h=418bbcf4&itok=SYi-pj2p)