1. Dept. of Construction Engineering and Management, Univ. Católica de Chile, Escuela de Ingeniera, Casilla 306, Correo 22, Santiago, Chile.
2. Professor of Civil Engineering, Dept. of Construction Engineering and Management, Univ. Católica de Chile, Escuela de Ingeniera, Casilla 306, Correo 22, Santiago, Chile.
3. Associate Professor of Mining Engineering, Mining Center, Univ. Católica de Chile, Escuela de Ingeniera, Casilla 306, Correo 22, Santiago, Chile.