1. Professor, Dept. of Biosystems Engineering and Soil Science, Univ. of Tennessee, Knoxville, TN 37996-4531 (corresponding author).
2. Research Assistant, Faculty of Engineering, Dept. of Geological Engineering, Univ. of Akdeniz, Dumlupinar Bulv. 07058, Antalya, Turkey; Ph.D. Candidate, Department of Geological Engineering, Middle East Technical Univ., 06531 Ankara, Turkey; formerly, Visiting Scholar, Dept. of Civil and Environmental Engineering, Univ. of Tennessee, Knoxville, TN 37996-2010.
3. Professor, Dept. of Geological Engineering, Middle East Technical Univ., 06531 Ankara, Turkey.
4. Associate Professor, Dept. of Mining Engineering, Middle East Technical Univ., 06531 Ankara, Turkey.