The U.S. Bureau of Mines is conducting research on a computer- assisted mining machine. Such a machine holds great promise for increased productivity and improved health and safety in the working section. A key element of such a machine is a coal interface detection (cid) system that can distinguish coal from noncoal material, no matter how complex the geology. Although much research has been done in the past by others in this area, there is still no general solution to the problem. Present Bureau cid research is focused on adaptive signal discrimination methods for analyzing the vibration of the mining machine, advanced infrared thermography, modern video systems, natural gamma emissions, advanced radar methods, and geological conditions. It appears that a suite of sensors with associated data analysis may result in a practical system.