Building the foundation for Chimney Hollow requires complex work to ensure the base of the dam is firmly set in place and subsurface seepage is mitigated. 

To accomplish that task, crews are using the Sandvik Ranger DX800 drill rig to drill into the bedrock at the site. The self-propelled drill unit is marketed as being “engineered for work in challenging terrain,” which certainly is the case in the undulating bedrock of the Chimney Hollow Reservoir site. 

Crews use the approximate 4-inch holes drilled by the unit as ground anchor holes, effectively tying the ground to the overlying embankment and to provide the means for construction of additional features in the foundation in the coming months.  Additionally, crews will use the 4-inch holes as a conduit for injecting grout into the foundation subsurface, which will fill fissures and voids in the bedrock reducing the potential for seepage.