Mr. Eoin McGrath:

The manufacturer has to get a geologist before they produce any aggregate that is going to be used in concrete products. That is prior to a block being made. Once the rock goes into a block I know nothing else about it. Once it is not rock anymore my expertise is done. The geologist has to come in and make a statement this particular rock is suitable for use in concrete, use in subfloor fill or use in mortar, those being SR 16, SR 21 and SR 18.