How to pump sand or kaolin clay with a dredge?

Sand and kaolin clay are two unique types of material.  Sand is much more abrasive and must be pumped with hardened steel pumps and cutterhead wear parts.  Kaolin is less abrasive but must be pumped efficiently, often at long distances to be economical.  Hydraulic mining is often used when the source is dry.  Dredges are used when the water table is above the source of material.