>>1660624These mines are all dry hard rock mines. Most the timbering was in good shape. The support give way for a variety of reasons. Wood was not easy or cheap to get to these mines so they only used it in weak areas. Some areas this timbering in helping to support hundreds of tons of rock. Mines are typically dug near or on fault lines. The slow shifting of the rock makes certain areas weak over time.
The fault line in this mine is the right side of the haulage tunnel. Rock on fault lines is smooth and flat.
