1. Dept. of Natural Resources and Environmental Engineering, School of Mining Engineering, Univ. of Vigo, Maxwell s/n, 36310 Vigo, Spain (corresponding author).
2. Dept. of Natural Resources and Environmental Engineering, School of Mining Engineering, Univ. of Vigo, Maxwell s/n, 36310 Vigo, Spain.
3. Dept. of Materials Engineering, Applied Mechanics and Construction, School of Industrial Engineering, Univ. of Vigo, Torrecedeira 86, 36208 Vigo, Spain.