Long-Term Stability of a 13.7 × 30.5-m (45 × 100-ft) Undercut Span Beneath Cemented Rockfill at the Turquoise Ridge Mine, Nevada

内华达州绿松石岭矿水泥岩填料下方13.7米×30.5米（45英尺×100英尺）底切跨度的长期稳定性