Support of underground openings is much the same for both large and small mining operations. Essentially, the difference lies in the depth and in the extent to which the two types of wo… See more

Ordinarily, one must know rock mechanics to estimate ground loads. For the underground conditions usually encountered in shallow- to medium-depth operations… See more

Posts are ordinarily selected to act as columns which must resist bending from the side pressure ph, and are also checked for bearing against the spreader on the bottom sid… See more

The cap and posts in the preceding discussion were selected by methods using conventional working stresses for the material; these values were originally selected fo… See more

With few exceptions, humid conditions underground promote decay. Treatment of mine timber helps to slow down or prevent decay. Timber from which the bark is removed h… See more