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Splitting boulders under water

Stone Trust Professional Member John Sandri writes:
A customer recently contacted us about a unique project, after having heard we could split boulders.  They were trying to move boulders from their swimming area that were a danger to swimmers jumping or diving off the dock.  A customized crane boat was brought in to move the boulders, but was only able to lift 3 tons, and many of these rocks were 6-52 tons in size.  We were tasked with figuring out a way to split the boulders underwater into small enough pieces for the crane boat to move.  With the proper permitting in place and not being able to use explosives, we decided to utilize a 70 lb. pneumatic rock hammer drill that we could submerge underwater to drill the holes.  We dove using snorkels to insert the feathers and wedges, and again dove to pound them in using large sledges and weight belts to keep us down.  There were many original challenges we faced trying to complete the work underwater and found that each boulder’s unique size, shape and position in the water required a new set of problems to be solved.  I thought this project may have been of interest to the Stone Trust newsletter readers and decided to share!
-John Sandri, Sandri Stone, Harrisville, NH
feathers&wedges underwater 2
feathers&wedges underwater