Mines are a typical example of places where there is no stable or constant horizontal surface in which to set a control point. The floor of any mine is routinely covered over with dust or debris or disturbed by mechanical traffic. A vertical surface is the only place to set your control points. The BenchTie is the only control point designed specifically for a vertical surface. The shank was specifically designed for a dry fit after drilling a 1/4 inch hole with a masonry or rock bit. The dimple gives a fixed location for the tip of a range pole.
The body is made from a high-density impact resistant plastic which is molded around a 5" hardened spike. A recessed dimple on the top accepts the point of a prism pole for positive location. The flat surface around the dimple can be the stable location for any other measuring devices or stadia rod.
The secured bright yellow tag can be used to record critical information, control elevation or coordinates. Since the product has been on the market for two years, it will also serve as an indicator that a new electronic survey has recently been performed in this mine.
BenchTie is currently working with Mine Safety Divisions to establish this standard.