Bridging of material in ore passes causes blockages in the flow of material. These blockages can be hazardous and must be removed before production can continue. Sensors are available that can determine fill level form the top of an ore pass, but there are presently no sensors available that can determine both fill level and the position of a blockage. If information can be obtained regarding the location of a blockage, the depth of the material above the blockage, and the distance form the outlet can be determined. This information is needed to determine the safest and most effective method for removing the blockage.