70 Mg/day of fine grained waste gneiss in slurry condition, together with 700 m3/day or water from the wet bencfication plant flow from the Miklcuśka gneiss quarry (Croatia) into the Kamcnjaća stream. The stream flows between two gneiss quarries, originating in the northern catchment area or which approximately 15 km2 is predominantly covered by forest. The quality ofwater in the Kamcnjaća permanent stream should be protected from any contamination due to the activities in the Miklcuśka quarry. The paper describes the aspects of sustainable technical, environmental and economical protection ofthe water quality in Karncnjaća regarding gneiss mining.