Tin mining methods and processes

The Tin Mine is the world's largest antimony ore resource base, and the main ore body is a gently inclined layered medium-thick ore body. For a long time, traditional mining methods have mainly adopted cemented filling, open-pit room-and-pillar mining, etc. However, as the mining depth increases, the ore body becomes more complex - the inclination is steeper (from gently inclined) and the thickness becomes thinner (the section height increases from 36 meters to 50 meters), and the traditional method is inefficient. To solve this problem, we have developed innovative technologies for different ore body characteristics, which greatly improves recovery and safety.

1. Pillar Mortar Filling Mining Method

Applicable Conditions:

• Moderately stable or unstable roof with weak layers<1.5 m thick;

• Ore body dip ≤35°, thickness ≤6 m.

Workflow and Design:

1. Stope Layout: Stopes are arranged perpendicular to the strike, divided into ribs and rooms. Ribs (6 m wide) are backfilled with C10 cement; rooms are filled post-extraction.

2. Drilling and Blasting: YT28 drill rigs create 42 mm holes (2.0 m deep). 2# rock emulsion explosives with non-electric detonators are used.

3. Roof Support: Quick-hardening cement anchor bolts (1.8–2.2 m long, 0.9×0.9 m spacing) limit unsupported areas to ≤6 m².

4. Filling: Slurry (71% solid content, cement:tailing=3:1–4:1) fills stopes in one pass, cured for 24 hours.

Advantages:

• Eliminates roof ore layers, boosting recovery;

• Two-stage filling mitigates ground pressure risks.

2. Wall Filling (Hydraulic Pillar Roof Support) Method

Applicable Conditions:

• Ore thickness 0.8–3.5 m, dip<35°;

• Stable ore body with moderately stable hanging wall.

Key Techniques:

1. Stope Layout: Stopes (6–8 m wide) advance from low to high elevation.

2. Roof Support: SYZ hydraulic pillars (2–3 m spacing, 1.5 m intervals) are installed >5 m from blast points.

3. Filling Management: 0.6–0.8 m bulkheads ensure tight filling, minimizing roof exposure.

Innovations:

• Active hydraulic support replaces passive methods;

• Dynamic filling adjustments enhance stability.

• 3. Upward Continuous Mining for Steeply Inclined Thin Ore Bodies

Applicable Conditions:

• Dip >40°, thickness ≤4 m;

• Moderately stable roof with simple fractures.

Process Design:

1. Stope Structure: Stopes (50–60 m long) use 3 m lifts, with 2.0×2.0 m ventilation shafts and drawpoints.

2. Extraction Sequence: Retreat mining requires bolt installation within 24 hours post-blast (1.0×1.0 m spacing, 0.8×0.8 m in fractured zones).

3. Filling: Each lift is filled within 1 month, with 0.5–1.0 m cemented isolation layers and drainage systems.

Critical Controls:

• Strict blast hole angles prevent roof penetration;

• Continuous operations avoid stope interruptions.

• 4. Performance and Economic Benefits

Field data demonstrate significant improvements:

1. Recovery Rate: Pillar mortar filling reduces pillar loss, increasing recovery by 15%;

2. Safety: Hydraulic pillars cut roof collapse incidents by 60%;

3. Cost Efficiency: Cemented filling material utilization rises 20%, saving ¥8 million annually.

For example, upward continuous mining achieved 1,500 t/month per stope, reducing ore loss from 12% to 5% and boosting profits by 30%.