1. Department of Mining Exploitation and Prospecting, School of Mining, Energy and Materials Engineering, University of Oviedo, C/Independencia 13, 33004 Oviedo, Spain
2. Instituto Nacional de Silicosis, C/La Minería 1, 33011 Oviedo, Spain
3. Global Service, C/Suero de Quiñones 24, 24002 León, Spain
4. Recuperación y Renovación SL, C/Santa Susana 29, 33007 Oviedo, Spain