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MoDOT I-470 & Pryor Road Interchange

Owner: Missouri Department of Transportation (MoDOT) – District 4
Client: Pyramid Contractors, Inc.
Location: Lee’s Summit, Missouri
Services: Drilling, Non-Destructive Testing

The interchange project includes the remediation of the abandoned limestone mines from the old Union Quarries located next to the I-470 right of way near the proposed Pryor Road interchange in Lee’s Summit, Missouri. Room and Pillar mining occurred at this site between 1965 and 1981. In addition, two sets of tunnels were advanced under what is now I-470. During the surveying phase of the project in 2006, MoDOT personnel observed several “dome-outs” within or near the project site. Dome-outs occur where the bedrock roof above a mine fails. Progressive failure of the roof results in subsidence features visible at the ground surface. It was reported that the mined areas have experienced numerous subsurface roof failures and surface subsidence since the mine closure.

Geotechnology developed the technical requirements for the mine remediation, which included determining which portions of the mine had to be filled, what materials to use and the testing requirements. Project specifications developed by Geotechnology included materials properties, injection location, injection limits and verification requirements for remediation of the mine on this project site that is adjacent to an active interstate highway. Geotechnology also developed the remediation project estimate and construction schedule and investigated alternative solutions for mine remediation and selected the use of low-strength fly ash grout for infill and barrier walls.

Geotechnology was also available to provide consultation as requested during construction.