In the first 15 minutes the grout taken down the hole was 24.00 cu ft [680 litres]. This is a very large take.
This grouting was done with 0.8:1 grout. It is obvious that the hole will take thicker grout without getting blockages. However the grouting would not be impaired by continuing to use this mix for the next 15 minutes, if you wish - but it is not the best thing to do. More water would be injected than is really necessary and this is contrary to best practice, which is to use as little water as possible.
It is necessary to decide what to do next. The choice is from one of the following: