War Games - Evaluating Risk-PPT Presentation

PPT Presentation

Pdf Summary

The presentation reviews geologic hazards and risk management at Cheyenne Mountain Air Force Station, home to NORAD southwest of Colorado Springs. Built in granite between 1961 and 1964 and opened in 1965, the facility is also surrounded by slopes with a history of landslides.<br /><br />The site geology includes granite bedrock and colluvium over upturned, sloping shale. Heavy rainfall in September 2013—up to 8 inches in one hour and 15 inches over several days—triggered major debris movement. An estimated 10,000 cubic yards were removed, and ringnets were installed.<br /><br />A broader risk assessment identified seven areas of concern, including the North Portal Ravine and six slope-stability areas. In the ravine, investigators estimated another 30,000–40,000 cubic yards of potential debris, compared with existing ringnet and basin capacities totaling about 13,000 cubic yards. Options included adding ringnets and maintaining them through proactive inspections; significant debris had already accumulated within two years.<br /><br />Slope investigations used geotechnical drilling, rock coring, geophysical testing, and laboratory analyses. Findings highlighted sloping shale as a key hazard, particularly when wet or affected by previous failures. Its measured peak strength fell by 73% under wet conditions, and testing also found substantial swell potential. One evaluated slope had factors of safety ranging from 0.8 to 1.7, averaging 1.15. After considering options such as slope flattening and soil nails, a retaining wall was recommended.<br /><br />The presentation’s main lessons are to conduct a comprehensive risk assessment, use creative methods when conventional exploration is impractical, and help clients manage risks affecting mission-critical operations. It also advises visitors not to move around the station without an escort.

Keywords

Cheyenne Mountain Air Force Station

NORAD

geologic hazards

risk management

landslides

granite bedrock

shale slopes

debris flow

ringnets

slope stability