The purpose of this paper is to outline the findings of the evaluation of the grinding process of limonite and serpentine minerals present in oxidized Ni-Co ores, which are contained in the lateritic soils of the north-eastern region of Cuba. The grindability study supporting this paper was based on the execution of various tests aiming to determine the influence of mineral content in breakage and selection functions, and in the Bond work index. The results obtained shows that grinding behaviour of each mineral component does not depend on the mineral content in the sample. (c) 2007 Elsevier B.V. All rights reserved.