Mike Mueller, Brent Willeford and Greg Snellen - Land Reclamation Program, Abandoned Mined Lands Unit recognized for work to repair collapsed mine shaft sinkhole in eastern Springfield.

Greg Snellen, Mike Mueller and Brent Willeford photo.

On Jan. 31, 2013, DNR’s Southwest Regional Office in Springfield notified the Land Reclamation Program of the collapsed mine shaft, which caused a large sinkhole and significant structural damage to two houses directly adjacent to the collapse. The damage to the footing and foundation of the two homes created an immediate safety and health hazard to the occupants living there.

Upon learning of the collapse, Mike Mueller, Brent Willeford and Greg Snellen responded to a mine shaft collapse in eastern Springfield. All three work for the department’s Land Reclamation Program, Abandoned Mined Lands Unit, or AML, in Jefferson City. Mueller, Willeford and Snellen took swift action, dropping all other duties, to better coordinate the investigation and initiate a remedy. As a team, responsibilities were divided and the men immediately coordinated with the regional office, landowners, the department’s Missouri Geological Survey and the Greene County Resource Management Department.

Before taking physical action, it was imperative to obtain any current and historical data regarding the abandoned mine. After confirming the collapse to be mine-related and collecting as much information as possible, the staff rushed to Springfield and established an on-site project coordination and command post. Mueller, Willeford and Snellen arrived at 1 p.m. on Jan. 31.

From there, the AML staff worked expeditiously, late into the evening and the next day, to characterize the site and situation and devise a plan for correcting the problems. It also was critical to eliminate the immediate safety risk to the homeowners and residences and assure them the collapse would be mitigated without labor or materials costs to them.

“We couldn’t just go in and start operations without approval from the federal Office of Surface Mining,” said Kevin Mohammadi, director of DNR’s Land Reclamation Program. “Staff worked swiftly with the OSM to declare the situation an emergency, approve the mitigation plan and complete the project as soon as possible.”

The AML team worked continuously during this period to assure all contracting and OSM administrative requirements were satisfied in accordance with regulation. The employees took the initiative and made the extra effort to successfully stabilize the homes to prevent further damage and risk. Once the immediate risks were remedied, Mueller, Willeford and Snellen devoted all of their time to coordinate the design and construction of the cast-in-place concrete beam, structural support piers, and concrete seal, using emergency procurement procedures to pay for the work. Mueller focused his expertise on project oversight and funding procurement. Willeford directed his efforts toward engineering oversight and contractor coordination, and Snellen worked as a liaison between landowners and contractors.

The short-term effort to temporarily stabilize both homes required the installation of base rock materials into the collapse and the construction of temporary supports for the footings and foundations of both homes. This was necessary in order to excavate the sinkhole and explore it in order to determine the exact dimensions of the mineshaft and associated collapse. Once complete, their work was directed toward a long-term solution. This required that a rebar-reinforced concrete plug be installed to permanently seal the shaft subsidence and prevent any future collapse or structural damage from occurring.

“All three employees recognized the urgency of the situation with regard to safety of the residents, potential for the loss of properties, and inconvenience to the residents – they made the project ‘high priority,’” said Mohammadi.

Mike Mueller resides in Jefferson City and joined the Missouri Department of Natural Resources in 1995. Brent Willeford lives in Rolla and started with DNR in 2004. Greg Snellen is from Henley and began his employment with the State of Missouri in 2002, joining DNR in 2009.