Anhydrite | 157 | Roof rocks |
Limy dolomite (I) | 8 | |
Limy dolomite (I) | 9 | |
Compact limy dolomite (II) | 1.0 | |
Compact limy dolomite (II) | 0.7 | |
Compact limy dolomite (II) | 0.5 | |
Dolomite + shale | 2.0 | Copper deposit |
Grey sandstone | 4.4 | Floor rocks |
Red sandstone | 200 |
Anhydrite | 3.60 | 2.25 | 34.0 | 2.40 | 1.10 | 2950 |
Dolomite, limestone upper | 2.70 | 1.84 | 45.0 | 2.20 | 0.93 | 2750 |
Dolomite, limestone lower | 2.40 | 1.70 | 42.0 | 1.70 | 0.70 | 2650 |
Copper deposit | 1.80 | 1.40 | 27.0 | 1.35 | 0.60 | 2600 |
Grey sandstone | 1.30 | 1.10 | 32.0 | 1.25 | 0.50 | 2200 |
Red sandstone | 0.80 | 0.70 | 30.0 | 1.08 | 0.45 | 1900 |
Rockbolt diameter, m | 0.02 | Cable diameter, m | 0.0155 |
Young's modulus, GPa | 200 | Young's modulus, GPa | 200 |
Cross-sectional area, m2 | 3.14e-4 | Cross-sectional area, m2 | 1.89e-4 |
Exposed perimeter, m | 0.063 | Exposed perimeter, m | 0.049 |
Axial tensile yield strength, N | 153e3 | Tensile yield strength, N | 250e3 |
Normal coupling spring cohesion, N/m | 2e6 | Grout cohesive strength (force), N/m | 190e3 |
Shear coupling spring | 0.5e6 | Grout stiffness, | 0.4e10 |
cohesion, N/m | N/m/m | ||
Normal coupling spring stiffness, N/m/m | 1e10 | ||
Shear coupling spring stiffness, N/m/m | 40e6 |
Dolomite, limestone lower | 2.40 | 1.70 | 42.0 | 1.70 | 0.70 | 2650 | 32 | 0.7 | 0.15 |
Copper deposit | 1.80 | 1.40 | 27.0 | 1.35 | 0.60 | 2600 | 22 | 0.35 | 0.10 |
Anhydrite | 21.6 | 13.5 | 34 | 14.5 | 6.4 | 92.6 | 2950 |
Dolomite, limestone upper (I) | 16.07 | 11.07 | 45 | 12.8 | 5.5 | 115.5 | 2750 |
Dolomite, limestone lower (II) | 14.72 | 10.13 | 42 | 10.0 | 4.2 | 60.0 | 2650 |
Copper deposit | 11.27 | 8.44 | 27 | 8.0 | 3.5 | 68.0 | 2600 |
Grey sandstone | 5.12 | 4.32 | 32 | 5.6 | 2.0 | 37.0 | 2200 |
Red sandstone | 3.72 | 3.36 | 30 | 4.8 | 1.1 | 25.6 | 1900 |
Tip-to-face distance | 3.0 m | 1.5 m |
Average load-bearing capacity | 2600 kN | 4000 kN |
Spacing of box crib | Every 6.0 m | Every 3.0 m, 1.5 m |
Roof control method – hydraulic backfilling (sand) instead of box crib | No | Yes |