Statistics show that falls of ground (i.e., roof or rib rock) are responsible for a high number of mining injuries and fatalities. In all of mining, workers in the underground stone sector face the most serious risk from fall of ground, according to Mine Safety and Health Administration injury statistics from 1992 to 1996. In addition to the present dangers associated with underground stone mining, national trends indicate that this sector will expand in future years. A proactive approach toward understanding roof behavior allows for mine planning and development that affords the safest condition for the mine worker. In the United States, there are currently approximately 95 underground stone mines (predominantly limestone). The stone produced is used primarily for construction and secondarily for lime in chemical applications. During the past few years, the Pittsburgh Research Laboratory of NIOSH examined and characterized conditions at 43 underground stone mines. Observations during these visits revealed a limited degree of roof monitoring beyond visual inspection. Existing monitors typically require the miner to measure movement at the roof. If conditions are unstable, the miner may be in harm's way while recording data. Based on these circumstances, researchers concluded that a simple, inexpensive monitoring instrument with the capability for remote readings could lead to a safer way of recording data, as well as more widespread monitoring and understanding of roof movements. A monitor to meet this need was subsequently designed and tested.