Kure-Bakibaba pyritic copper ore of Turkey is easily altered and, therefore, is not floated and separated readily front gangue minerals, in particular from pyrite. During alteration first iron sulphates are formed which have presumably depressing effects oil copper minerals flotation. Flotation tests were carried out with additions of CaCO3, and CaO separately during grinding and with CuSO4 addition in flotation. Flotation tests with improved results were obtained. (C) 2004 Elsevier B.V. All rights reserved.