Affiliation: | 1. Department of Construction and Manufacture Engineering, Engineering School of Gijon, University of Oviedo, Campus de Viesques, 33201 Asturias, Spain;2. Department of Mining Engineering, Mining Engineering School, University of Oviedo, Independencia 13, 33004 Asturias, Spain;3. Department of Mathematics, Mining Engineering School, University of Oviedo, Independencia 13, 33004 Asturias, Spain |