Sentence Examples

  • The subdrift caving system, fig.
  • The bottom-slice caving system of mining begins at the bottom of a hundred-foot block of ground, a floor being excavated under the whole area, leaving pillars of sufficient size to support the ground above.
  • While the mine workings are small the overlying rocks support themselves of and the full pressure does not come upon the mine Caving p i llars.
  • The caving-in of the mine, however, is rarely so complete that avenues of escape are not open.
  • 9 illustrates the working of a block of ground by the top-slice caving system.