Specifications include, but are not limited to: Forestville Mystery Cave consists of approximately 13 miles of underground passages and caverns carved out of compressed layers of limestone, shale and sandstone. In 2008, a section of unconsolidated fill along a wall of the Cathedral Passage collapsed blocking the entrance to the cavern. The Minnesota Department of Natural Resources (DNR), Operations Services Division, and Parks and Trails Division requests proposals from consulting firms to perform an initial assessment to perform a detailed survey to identify hazards, develop plans, specifications and estimate for the safe removal of the rubble and provide technical support for administration of the construction contract. After completion of the removal, perform stability analysis and risk analysis of the cavern’s structural stability, and potentially provide final design as necessary for structural supports or protective walkway enclosures.
