Reducing smelting of preliminarily roasted copper sulfide concentrate even without addition of dope collector-phase, allows effectively extract copper and precious metals to the bottom phase (blister copper). Experimental investigation of impact of some parameters of smelting, such as concentrations of SiO₂, CaO, Na₂O in slag and temperature to the distribution of gold and silver was conducted, using charcoal as reductant. Obtained results show, that optimal slag composition in case of minimization of precious metals losses is: Na₂O 6–7 %, CaO — 12–18 %, SiO₂ — 32–36 %. Optimal process temperature is 1573 K.