· Hi, We are interested in a limestone mine for GCC production. At the moment, we are trying to achieve GCC powder of 15 micron. We intend to grind limestones and to produce GCC using three successive processes. The first process is to grind down to 30 micron and the second process is to grind to the final ultrafine size of 15 micron and the third process is the separation of the powders .