Circular 69 — How to Measure Rock Pressures: New Tools and Proved Techniques Aid Mine Design

By George B. Griswold, 1963, 8 pages.

For a rock pressure measurement to have significance, it must be performed in solid rock beyond the blast-fractured zone adjacent to a mine opening. Furthermore, if premining stress is desired, the measurement must be made at a distance sufficient to escape the deflected s_tress envelope surrounding the mine opening. While Hast and USBM techniques satisfy these requirements, a newly developed 3-axis gage can make a stress determination for each stress relief core -a real asset when measurements are made in highly fractured rock.

Besides describing this gage, this article will detail the development of rock pressure measuring systems. Tools, techniques and mathematical formulas will be reviewed.