The photo on the left was taken on Aug 2 and shows the initial pour for the “mud mat” placed directly on clean, solid bedrock.
The photo below shows the tank slab floor forms placed on the mud mat on August 4.
Many thanks to SMRC Dave Blanchette for guiding the structural nuances of the concrete work and to Kumar and Associates' Greg Demming and Steve Mulligan for regular materials testing including concrete quality control.
Solid as a rock we will be!