Marble Underground Mining Technology and Comparative Analysis with Open-Pit Mining

Marble Underground Mining Technology and Comparative Analysis with Open-Pit Mining

I. Underground Mining Process Flow

1. 3D Exploration & Positioning

Utilizes geological radar (100MHz frequency) combined with core sampling (Φ110mm drill bit) to precisely locate high-quality ore veins, establishing a 3D underground model with positioning accuracy of ±0.5m.

2. Tunnel Excavation

Employs TBM (Tunnel Boring Machine, 3.5m diameter) to advance along ore veins, with simultaneous installation of steel arch supports (0.8m spacing). Ventilation systems maintain oxygen concentration >19.5%.

3. Mechanical Cutting

Diamond wire saws (11mm diameter) cut along vertical joint surfaces at 0.8-1.2m²/h, assisted by high-pressure water mist dust suppression (3.5MPa pressure).

4. Block Transportation

Custom rail carts (15t capacity) transport blocks through inclined tunnels (8° slope), with in-tunnel haulage distance limited to 500m.

II. Comparative Analysis with Open-Pit Mining

Key Difference: Underground mining achieves "point development," while open-pit causes "areal destruction." Tunnel support accounts for 35% of total underground costs, versus 18% for open-pit reclamation expenses.

III. Technical-Economic Analysis of Underground Mining

1. Geological Adaptability

Optimal for steeply dipping deposits (>60° inclination), e.g., Cangshan Mine in Yunnan. Efficiency drops 40% for horizontal ore bodies.

2. Economic Threshold

Economically viable when deposits meet:

Block recovery rate >50%

Ore body thickness >8m

Proximity to sensitive areas (<1km from settlements)

3. Innovation Trends

5G remote control systems reducing underground risks

Real-time laser scanning modeling (±2cm accuracy)

Backfill mining (waste recycling rate >90%)

Case Study: Italy's Carrara mining area maintains 120km+ tunnels with 100-year continuous production, achieving 25% higher recovery than open-pit. Currently, China's underground mining accounts for <8% of total production, projected to reach 20% by 2030 under ecological red line and smart mining policies.

This technology proves particularly suitable for urban periphery mines and scenic protection zones. Although initial investments are 60% higher, full lifecycle benefits increase 2-3 fold.