What must not occur after the placement of cement grout in well casing?

After the placement of cement grout in well casing, moving or driving the permanent well casing must not occur. This is because once the grout is in place, it needs to set and harden to create a stable seal around the well casing. Any movement of the casing during this time can disrupt the integrity of the grout, potentially leading to voids or weak points in the seal. This could result in contamination of the groundwater or failure to properly support the casing, which is crucial for the well's structural integrity.

The other options do not interfere with the cement grout's role. Inspection of the casing may be necessary to ensure that the casing is properly positioned and that there are no defects. The placement of additional materials, as long as it's done following the grouting procedure and does not disturb the grout itself, is also permissible. Likewise, withdrawal of the casing typically occurs before grouting is applied and should not impact the hardened grout once it has set.