Figure 1.
Schematic diagram of pillar stress.
Figure 1.
Schematic diagram of pillar stress.
Figure 2.
Schematic diagram of pillar bearing calculation.
Figure 2.
Schematic diagram of pillar bearing calculation.
Figure 3.
Picture of pillar in Bainiuchang mine.
Figure 3.
Picture of pillar in Bainiuchang mine.
Figure 4.
Arrangement and mining sequence of rooms and pillars.
Figure 4.
Arrangement and mining sequence of rooms and pillars.
Figure 5.
Finite element calculation model.
Figure 5.
Finite element calculation model.
Figure 6.
Finite element model meshing.
Figure 6.
Finite element model meshing.
Figure 7.
Dead-weight stress field calculation results.
Figure 7.
Dead-weight stress field calculation results.
Figure 8.
Maximum principal stress distribution in the ore block at 1480 mL before mining (parameters before optimization: stope height 3 m, pillar diameter 3 m, pillar spacing 7 m, pillar row spacing 9 m).
Figure 8.
Maximum principal stress distribution in the ore block at 1480 mL before mining (parameters before optimization: stope height 3 m, pillar diameter 3 m, pillar spacing 7 m, pillar row spacing 9 m).
Figure 9.
Minimum principal stress distribution in the block at 1480 mL before mining (parameters before optimization: stope height 3 m, pillar diameter 3 m, pillar spacing 7 m, pillar row spacing 9 m).
Figure 9.
Minimum principal stress distribution in the block at 1480 mL before mining (parameters before optimization: stope height 3 m, pillar diameter 3 m, pillar spacing 7 m, pillar row spacing 9 m).
Figure 10.
Maximum principal stress distribution in the ore block at 1480 mL after mining the strip room (parameters before optimization: stope height 3 m, pillar diameter 3 m, pillar spacing 7 m, pillar row spacing 9 m).
Figure 10.
Maximum principal stress distribution in the ore block at 1480 mL after mining the strip room (parameters before optimization: stope height 3 m, pillar diameter 3 m, pillar spacing 7 m, pillar row spacing 9 m).
Figure 11.
Minimum principal stress distribution in the ore block at 1480 mL after mining the strip room (parameters before optimization: stope height 3 m, pillar diameter 3 m, pillar spacing 7 m, pillar row spacing 9 m).
Figure 11.
Minimum principal stress distribution in the ore block at 1480 mL after mining the strip room (parameters before optimization: stope height 3 m, pillar diameter 3 m, pillar spacing 7 m, pillar row spacing 9 m).
Figure 12.
Maximum principal stress distribution in the ore block at 1480 mL after mining of strip pillars (parameters before optimization: stope height 3 m, pillar diameter 3 m, pillar spacing 7 m, pillar row spacing 9 m).
Figure 12.
Maximum principal stress distribution in the ore block at 1480 mL after mining of strip pillars (parameters before optimization: stope height 3 m, pillar diameter 3 m, pillar spacing 7 m, pillar row spacing 9 m).
Figure 13.
Minimum principal stress distribution in the ore block at 1480 mL after mining of strip pillars (parameters before optimization: stope height 3 m, pillar diameter 3 m, pillar spacing 7 m, pillar row spacing 9 m).
Figure 13.
Minimum principal stress distribution in the ore block at 1480 mL after mining of strip pillars (parameters before optimization: stope height 3 m, pillar diameter 3 m, pillar spacing 7 m, pillar row spacing 9 m).
Figure 14.
Nine schemes of room and pillar configurations (a) Scheme 1; (b) Scheme 2; (c) Scheme 3; (d) Scheme 4; (e) Scheme 5; (f) Scheme 6; (g) Scheme 7; (h) Scheme 8; (i) Scheme 9.
Figure 14.
Nine schemes of room and pillar configurations (a) Scheme 1; (b) Scheme 2; (c) Scheme 3; (d) Scheme 4; (e) Scheme 5; (f) Scheme 6; (g) Scheme 7; (h) Scheme 8; (i) Scheme 9.
Figure 15.
Maximum principal stress distribution of scheme 1 pillars at 1480 mL (parameters of scheme 1: stope height 2.5 m, pillar diameter 2 m, pillar spacing 4 m, pillar row spacing 6 m).
Figure 15.
Maximum principal stress distribution of scheme 1 pillars at 1480 mL (parameters of scheme 1: stope height 2.5 m, pillar diameter 2 m, pillar spacing 4 m, pillar row spacing 6 m).
Figure 16.
Maximum principal stress distribution in the middle of the pillar at 1480 mL of scheme 1 (parameters of scheme 1: stope height 2.5 m, pillar diameter 2 m, pillar spacing 4 m, pillar row spacing 6 m).
Figure 16.
Maximum principal stress distribution in the middle of the pillar at 1480 mL of scheme 1 (parameters of scheme 1: stope height 2.5 m, pillar diameter 2 m, pillar spacing 4 m, pillar row spacing 6 m).
Figure 17.
Minimum principal stress distribution of scheme 1 pillars at 1480 mL (parameters of scheme 1: stope height 2.5 m, pillar diameter 2 m, pillar spacing 4 m, pillar row spacing 6 m).
Figure 17.
Minimum principal stress distribution of scheme 1 pillars at 1480 mL (parameters of scheme 1: stope height 2.5 m, pillar diameter 2 m, pillar spacing 4 m, pillar row spacing 6 m).
Figure 18.
Minimum principal stress distribution in the middle of the pillar at 1480 mL of scheme 1 (parameters of scheme 1: stope height 2.5 m, pillar diameter 2 m, pillar spacing 4 m, pillar row spacing 6 m).
Figure 18.
Minimum principal stress distribution in the middle of the pillar at 1480 mL of scheme 1 (parameters of scheme 1: stope height 2.5 m, pillar diameter 2 m, pillar spacing 4 m, pillar row spacing 6 m).
Figure 19.
Maximum principal stress distribution of scheme 2 pillars at 1480 mL (parameters of scheme 2: stope height 2.5 m, pillar diameter 3 m, pillar spacing 6 m, pillar row spacing 8 m).
Figure 19.
Maximum principal stress distribution of scheme 2 pillars at 1480 mL (parameters of scheme 2: stope height 2.5 m, pillar diameter 3 m, pillar spacing 6 m, pillar row spacing 8 m).
Figure 20.
Maximum principal stress distribution in the middle of the pillar at 1480 mL of scheme 2 (parameters of scheme 2: stope height 2.5 m, pillar diameter 3 m, pillar spacing 6 m, pillar row spacing 8 m).
Figure 20.
Maximum principal stress distribution in the middle of the pillar at 1480 mL of scheme 2 (parameters of scheme 2: stope height 2.5 m, pillar diameter 3 m, pillar spacing 6 m, pillar row spacing 8 m).
Figure 21.
Minimum principal stress distribution of scheme 2 pillars at 1480 mL (parameters of scheme 2: stope height 2.5 m, pillar diameter 3 m, pillar spacing 6 m, pillar row spacing 8 m).
Figure 21.
Minimum principal stress distribution of scheme 2 pillars at 1480 mL (parameters of scheme 2: stope height 2.5 m, pillar diameter 3 m, pillar spacing 6 m, pillar row spacing 8 m).
Figure 22.
Minimum principal stress distribution in the middle of the pillar at 1480 mL of scheme 2 (parameters of scheme 2: stope height 2.5 m, pillar diameter 3 m, pillar spacing 6 m, pillar row spacing 8 m).
Figure 22.
Minimum principal stress distribution in the middle of the pillar at 1480 mL of scheme 2 (parameters of scheme 2: stope height 2.5 m, pillar diameter 3 m, pillar spacing 6 m, pillar row spacing 8 m).
Figure 23.
Maximum principal stress distribution of scheme 4 pillars at 1480 mL (parameters of scheme 4: stope height 3.5 m, pillar diameter 2 m, pillar spacing 5 m, pillar row spacing 8 m).
Figure 23.
Maximum principal stress distribution of scheme 4 pillars at 1480 mL (parameters of scheme 4: stope height 3.5 m, pillar diameter 2 m, pillar spacing 5 m, pillar row spacing 8 m).
Figure 24.
Maximum principal stress distribution in the middle of the pillar at 1480 mL of scheme 4 (parameters of scheme 4: stope height 3.5 m, pillar diameter 2 m, pillar spacing 5 m, pillar row spacing 8 m).
Figure 24.
Maximum principal stress distribution in the middle of the pillar at 1480 mL of scheme 4 (parameters of scheme 4: stope height 3.5 m, pillar diameter 2 m, pillar spacing 5 m, pillar row spacing 8 m).
Figure 25.
Minimum principal stress distribution of scheme 4 pillars at 1480 mL (parameters of scheme 4: stope height 3.5 m, pillar diameter 2 m, pillar spacing 5 m, pillar row spacing 8 m).
Figure 25.
Minimum principal stress distribution of scheme 4 pillars at 1480 mL (parameters of scheme 4: stope height 3.5 m, pillar diameter 2 m, pillar spacing 5 m, pillar row spacing 8 m).
Figure 26.
Minimum principal stress distribution in the middle of the pillar at 1480 mL of scheme 4 (parameters of scheme 4: stope height 3.5 m, pillar diameter 2 m, pillar spacing 5 m, pillar row spacing 8 m).
Figure 26.
Minimum principal stress distribution in the middle of the pillar at 1480 mL of scheme 4 (parameters of scheme 4: stope height 3.5 m, pillar diameter 2 m, pillar spacing 5 m, pillar row spacing 8 m).
Figure 27.
Maximum principal stress distribution of scheme 6 pillars at 1480 mL (parameters of scheme 6: stope height 3.5 m, pillar diameter 4 m, pillar spacing 6 m, pillar row spacing 9 m).
Figure 27.
Maximum principal stress distribution of scheme 6 pillars at 1480 mL (parameters of scheme 6: stope height 3.5 m, pillar diameter 4 m, pillar spacing 6 m, pillar row spacing 9 m).
Figure 28.
Maximum principal stress distribution in the middle of the pillar at 1480 mL of scheme 6 (parameters of scheme 6: stope height 3.5 m, pillar diameter 4 m, pillar spacing 6 m, pillar row spacing 9 m).
Figure 28.
Maximum principal stress distribution in the middle of the pillar at 1480 mL of scheme 6 (parameters of scheme 6: stope height 3.5 m, pillar diameter 4 m, pillar spacing 6 m, pillar row spacing 9 m).
Figure 29.
Minimum principal stress distribution of scheme 6 pillars at 1480 mL (parameters of scheme 6: stope height 3.5 m, pillar diameter 4 m, pillar spacing 6 m, pillar row spacing 9 m).
Figure 29.
Minimum principal stress distribution of scheme 6 pillars at 1480 mL (parameters of scheme 6: stope height 3.5 m, pillar diameter 4 m, pillar spacing 6 m, pillar row spacing 9 m).
Figure 30.
Minimum principal stress distribution in the middle of the pillar at 1480 mL of scheme 6 (parameters of scheme 6: stope height 3.5 m, pillar diameter 4 m, pillar spacing 6 m, pillar row spacing 9 m).
Figure 30.
Minimum principal stress distribution in the middle of the pillar at 1480 mL of scheme 6 (parameters of scheme 6: stope height 3.5 m, pillar diameter 4 m, pillar spacing 6 m, pillar row spacing 9 m).
Figure 31.
Maximum principal stress distribution of scheme 7 pillars at 1480 mL (parameters of scheme 7: stope height 4.5 m, pillar diameter 2 m, pillar spacing 6 m, pillar row spacing 7 m).
Figure 31.
Maximum principal stress distribution of scheme 7 pillars at 1480 mL (parameters of scheme 7: stope height 4.5 m, pillar diameter 2 m, pillar spacing 6 m, pillar row spacing 7 m).
Figure 32.
Maximum principal stress distribution in the middle of the pillar at 1480 mL of scheme 7 (parameters of scheme 7: stope height 4.5 m, pillar diameter 2 m, pillar spacing 6 m, pillar row spacing 7 m).
Figure 32.
Maximum principal stress distribution in the middle of the pillar at 1480 mL of scheme 7 (parameters of scheme 7: stope height 4.5 m, pillar diameter 2 m, pillar spacing 6 m, pillar row spacing 7 m).
Figure 33.
Minimum principal stress distribution of scheme 7 pillars at 1480 mL (parameters of scheme 7: stope height 4.5 m, pillar diameter 2 m, pillar spacing 6 m, pillar row spacing 7 m).
Figure 33.
Minimum principal stress distribution of scheme 7 pillars at 1480 mL (parameters of scheme 7: stope height 4.5 m, pillar diameter 2 m, pillar spacing 6 m, pillar row spacing 7 m).
Figure 34.
Minimum principal stress distribution in the middle of the pillar at 1480 mL of scheme 7 (parameters of scheme 7: stope height 4.5 m, pillar diameter 2 m, pillar spacing 6 m, pillar row spacing 7 m).
Figure 34.
Minimum principal stress distribution in the middle of the pillar at 1480 mL of scheme 7 (parameters of scheme 7: stope height 4.5 m, pillar diameter 2 m, pillar spacing 6 m, pillar row spacing 7 m).
Figure 35.
Maximum principal stress distribution of scheme 9 pillars at 1480 mL (parameters of scheme 9: stope height 4.5 m, pillar diameter 4 m, pillar spacing 7 m, pillar row spacing 8 m).
Figure 35.
Maximum principal stress distribution of scheme 9 pillars at 1480 mL (parameters of scheme 9: stope height 4.5 m, pillar diameter 4 m, pillar spacing 7 m, pillar row spacing 8 m).
Figure 36.
Maximum principal stress distribution in the middle of the pillar at 1480 mL of scheme 9 (parameters of scheme 9: stope height 4.5 m, pillar diameter 4 m, pillar spacing 7 m, pillar row spacing 8 m).
Figure 36.
Maximum principal stress distribution in the middle of the pillar at 1480 mL of scheme 9 (parameters of scheme 9: stope height 4.5 m, pillar diameter 4 m, pillar spacing 7 m, pillar row spacing 8 m).
Figure 37.
Minimum principal stress distribution of scheme 9 pillars at 1480 mL (parameters of scheme 9: stope height 4.5 m, pillar diameter 4 m, pillar spacing 7 m, pillar row spacing 8 m).
Figure 37.
Minimum principal stress distribution of scheme 9 pillars at 1480 mL (parameters of scheme 9: stope height 4.5 m, pillar diameter 4 m, pillar spacing 7 m, pillar row spacing 8 m).
Figure 38.
Minimum principal stress distribution in the middle of the pillar at 1480 mL of scheme 9 (parameters of scheme 9: stope height 4.5 m, pillar diameter 4 m, pillar spacing 7 m, pillar row spacing 8 m).
Figure 38.
Minimum principal stress distribution in the middle of the pillar at 1480 mL of scheme 9 (parameters of scheme 9: stope height 4.5 m, pillar diameter 4 m, pillar spacing 7 m, pillar row spacing 8 m).
Figure 39.
Maximum compressive stress in the ore pillars of schemes 1 to 9 (compared with the uniaxial compressive strength of the ore (97.62 MPa)).
Figure 39.
Maximum compressive stress in the ore pillars of schemes 1 to 9 (compared with the uniaxial compressive strength of the ore (97.62 MPa)).
Figure 40.
Designed ore recovery rate of schemes 1 to 9.
Figure 40.
Designed ore recovery rate of schemes 1 to 9.
Table 1.
Physical and mechanical parameters of Bainiuchang’s ore rocks.
Table 1.
Physical and mechanical parameters of Bainiuchang’s ore rocks.
Ore Rock Type | σc /MPa | σt /MPa | τ /MPa | c /MPa | φ /(°) | E /GPa | ρ /g·cm−3 | μ |
---|
Argillaceous Limestone | 58.30 | 3.76 | 36.81 | 3.47 | 28.38 | 9.37 | 2.74 | 0.25 |
Mudstone | 35.42 | 1.99 | 30.64 | 1.14 | 17.79 | 4.51 | 2.79 | 0.19 |
Siltstone | 77.14 | 2.78 | 37.57 | 4.08 | 35.97 | 14.88 | 2.64 | 0.27 |
Ore body | 97.62 | 2.07 | 50.86 | 6.58 | 42.93 | 12.60 | 4.00 | 0.22 |
Table 2.
Numerical simulation results of the recovery process before optimization.
Table 2.
Numerical simulation results of the recovery process before optimization.
No. | Stress Parameter | Step 1 (Before Mining) | Step 2 (Mining Strip Rooms) | Step 3 (Mining Strip Pillars) |
---|
1 | σ1 (MPa) | −1.84~−0.49 | −14.2~4.68 | −26.0~4.42 |
2 | σ2 (MPa) | −2.07~−0.98 | −16.3~−1.3 | −36.4~1.41 |
3 | σ3 (MPa) | −16.4~−12.5 | −68.5~−16.4 | −142.0~−10.9 |
4 | τxy (MPa) | −0.15~0.12 | −1.70~−1.54 | −9.48~9.63 |
5 | τyz (MPa) | −0.67~0.70 | −21.7~22.9 | −25.3~25.8 |
6 | τzx (MPa) | −0.007~0.177 | 2.16~2.83 | −32.3~34.7 |
Table 3.
Nine optimization schemes for orthogonal design.
Table 3.
Nine optimization schemes for orthogonal design.
| Factor | Stope Height/m | Pillar Diameter/m | Pillar Spacing/m | Pillar Row Spacing/m |
---|
Scheme | |
---|
1 | 2.5 | 2 | 4 | 6 |
2 | 2.5 | 3 | 6 | 8 |
3 | 2.5 | 4 | 8 | 10 |
4 | 3.5 | 2 | 5 | 8 |
5 | 3.5 | 3 | 7 | 7 |
6 | 3.5 | 4 | 6 | 9 |
7 | 4.5 | 2 | 6 | 7 |
8 | 4.5 | 3 | 5 | 9 |
9 | 4.5 | 4 | 7 | 8 |
Table 4.
Numerical calculation with stope height of 2.5 m.
Table 4.
Numerical calculation with stope height of 2.5 m.
No. | Stress Parameter | Scheme 1 | Scheme 2 | Scheme 3 |
---|
2 m × 4 m × 6 m | 3 m × 6 m × 8 m | 4 m × 8 m × 10 m |
---|
1 | σ1/MPa | −25.6~5.83 | −20.3~4.04 | −19.6~4.33 |
2 | σ3/MPa | −143.0~−1.98 | −118.0~−6.25 | −123.0~−6.22 |
3 | τxz/MPa | −33.7~36.3 | −27.9~27.4 | −28.0~25.0 |
Table 5.
Numerical calculation with stope height of 3.5 m.
Table 5.
Numerical calculation with stope height of 3.5 m.
No. | Stress Parameter | Scheme 4 | Scheme 5 | Scheme 6 |
---|
2 m × 5 m × 8 m | 3 m × 7 m × 7 m | 4 m × 6 m × 9 m |
---|
1 | σ1/MPa | −24.6~4.96 | −17.9~4.34 | −14.4~3.18 |
2 | σ3/MPa | −155.0~−1.08 | −123.0~−3.91 | −86.8~−6.46 |
3 | τxz/MPa | −39.9~37.3 | −28.0~27.2 | −19.6~19.6 |
Table 6.
Numerical calculation with stope height of 4.5 m.
Table 6.
Numerical calculation with stope height of 4.5 m.
No. | Stress Parameter | Scheme 7 | Scheme 8 | Scheme 9 |
---|
2 m × 6 m × 7 m | 3 m × 5 m × 9 m | 4 m × 7 m × 8 m |
---|
1 | σ1/MPa | −25.3~6.01 | −19.3~4.61 | −16.3~3.89 |
2 | σ3/MPa | −155.0~−1.1 | −113.0~−2.68 | −92.5~−4.78 |
3 | τxz/MPa | −35.3~37.8 | −27.6~28.3 | −20.6~21.0 |