Mines

Natural gas storage in excavated mines has been limited to only a few mines worldwide. The primary issue with CAES storage in a mine is the integrity of the mine structure: high-pressure air containment is typically poor because of the active geological environments associated with mined ore deposits. The Norton mine is unique because of a very stable geological environment and extremely low permeability limestone mine host rock.

Hydrodynamics and Sandia National Laboratories investigated the Norton Mine from 1999 to 2005 to characterize and analyze the mine for performance as a CAES storage vessel. Because high-pressure air has never been stored in a mine, Hydrodynamics and Sandia performed one of the most complex & extensive research programs of any mine in the United State and included:

• Geologic Mine Mapping for Integrity
• Exploratory Coring & Geophysical Borehole Logging
• Microscope Core Analysis & X-Ray Diffraction Analysis
• Rock Core Strength & Permeability Analysis
• In-Situ High Pressure Permeability Testing
• Finite Element Model of Mine for Stability Under Pressure
• Air Migration from Mine Face Numerical Modeling
• In-Situ Stress Measurements & Rock Strength Testing
• Mine Shaft Ground Penetrating Radar Survey
• Mine Shaft Spectral Analysis of Surface Waves

Specifically, Hydrodynamics and Sandia drilled over 600 feet of core samples, performed laboratory analysis of the core for rock strength and hydraulic properties, performed microscopic thin-section analysis, performed high pressure in-situ testing, performed in-situ stress measurements, numerical modeled air migration from the mine, and conducted a finite-element rock strength modeling analysis.

Additionally, Hydrodynamics prepared a conceptual mine shaft plug design, and designed the air injection and withdrawal well system for CAES performance. We also provided mine development support services that included:

• Mine Maintenance & Safety
• Underground Project Permitting
• Environmental Site Analysis
• Geotechnical Soil Foundation Investigation

The results of our research demonstrated the Norton Mine is cable of supporting approximately 2,700 MWe CAES power plants.