Clay is generally used to line ponds, to reduce seepage. There is no study about using rock dust fines to seal ponds. We look at some literature on this issue.
Farm ponds hold surface water that can be used to raise fish.
Clay at the bottom of the pond usually reduces seepage. There is a technique where organic matter left to rot, will lead to a anerobic bacterial slime layer, called gley, that acts as a water proof seal .
Using rock fines as clay, along with organic compost to create the anerobic slime layer, can be an eco-friendly way to seal ponds. Plastic liners degrade over time, and can tear easily.