A drilled hole, also called a drill hole is a hole drilled in bedrock or a large boulder. Some drill holes are used as reference marks or witness marks, while others are used as the station mark. Drill holes used as a station mark usually have metal in them, such as a brass or copper bolt, or are filled with lead. Drill holes can be in various diameters from about a half inch to two inches.

drilled hole (last edited 2009-03-21 21:03:18 by localhost)