In the first few minutes of grouting:

The pressure should be kept down to a low pressure such as 15 psi [1 bar] (or less) for a few minutes (typically 10 to 15 minutes) while checks are made for

• surface leaks
• connections to other holes
• rock movements
any other problem which could become worse if pressure is built up

Attention should be given to pressure gauge responses and to visual observation of the grout level in the agitator.

Maximum Pressures

Values of recommended maximum pressures are listed separately for traditional units and for metric units.

Modifications to these pressures may sometimes be necessary as discussed in the book Construction and Design of Cement Grouting by this author.