Cooperative efforts by the Bureau of Mines and Agapito & Associates, Inc., Grand Junction, Colorado, achieved the research objective of showing that data from measurements of the rate and change in rate of mine roof movement can be effective in detecting roof instability. Several instruments and techniques have been used to monitor roof movement and to detect imminent roof caves during pillar robbing. Early detection of unstable conditions can provide time either to withdraw personnel and equipment or to allocate supplemental support to prevent injury or downtime. Critical convergence rates were determined both manually and electronically. The detection of critical rate of movement has been shown to be an effective tool in ground control efforts.