The caving mining method is applicable to the surface to allow for caving. There is no large body of water and quicksand in the upper part of the ore body. The value of the ore is below medium, it will not agglomerate, the grade is not high, and the medium and thick ore bodies with certain loss and depletion are allowed. In particular, it is ideal for ore bodies with large natural collapse and moderately stable ore bodies. The caving mining method mainly includes wall caving method, sub-column sublevel caving method, sub-column sublevel caving method and stage caving method.
(1) Safety requirements for wall caving mining method
Safety measures for suspension, roofing, topping and roofing shall be specified in the design.
A thorough inspection is required before topping to ensure smooth outlets, good lighting and safe equipment.
When laying the roof, people are prohibited from staying in the roadway near the topping area.
In the dense pillars, every 3 to 5 m, there must be a safety outlet with a width of not less than 0.8 m. When the dense pillars are under pressure, reinforcement measures must be taken in time.
If the topping does not achieve the expected results, careful design should be made before the second topping can be carried out.
After the topping, the ceiling area should be closed in time, and personnel should not be allowed to enter.
When the multi-layered ore body slicing, must wait until after the upper stone slate roof caving and stable, before being allowed to the lower seam mining.
When the two adjacent middle sections are simultaneously harvested, the upper middle section mining working surface shall be inclined longer than the lower middle section working surface ahead of the working surface, and shall not be less than 20m.
The roof that cannot be self-propelled after the column is withdrawn shall be re-drilled and blasted to the topping area at 0.5m outside the dense pillar to force a caving.
The mechanical withdrawal of the column and the manual withdrawal of the column shall be carried out from the bottom up and from the far side. If the inclination of the ore body is less than 10Â°, the order of withdrawing the column is not limited.
(2) Safety requirements for sublevel caving mining method and stage caving method
The stopway of the stope shall have independent inlet and return air passages; the direction of transport of the electric raft shall be opposite to the direction of wind flow.
The communication path between the electric ramps shall be located on the wind side and on the side or rear of the electric winch.
Beside the electric tunnel, there must be a sidewalk with a width of not less than 0.8m.
Unrepaired electric ramps are not allowed to mine.
When using extrusion blasting, the compensation space and the amount of ore-mining should be controlled to avoid the occurrence of overhanging.
The bottom space should form a loose mat layer with a thickness of not less than 3 to 4 m.
The top of the stope shall have a covered rock layer with a thickness not less than the height of the caving layer; if the roof of the stope cannot fall by itself, it shall be forced to collapse in time or filled with filling material.
(3) Safety requirements for sublevel caving mining without sill
Above the mining face, there should be a covered rock layer larger than the section height to ensure the safety of the mining work. If the amount of rock that cannot be self-propelled or collapsed on the upper plate does not reach the specified thickness, forced topping must be carried out in time to make the thickness of the covered rock layer reach about twice the segment height.
When the upper and lower sections are simultaneously harvested, the upper section shall be ahead of the lower section. The excess distance shall be such that the upper section is outside the range of the displacement of the lower section of the mining face, and shall not be less than 20 m.
Each segmental contact road should have sufficient fresh air flow.
After the completion of each section, the slippery port of this section shall be closed in time.
(4) Safety requirements for stratified caving
The width of each stratified approach shall not exceed 3m and the stratified height shall not exceed 3.5m.
When the upper and lower layers are simultaneously harvested, the upper layer (in the horizontal direction) must be maintained above the adjacent lower layer for more than 15m.
When the false top is collapsed, personnel are prohibited from staying in the adjacent approach.
When the false top landing is blocked, it is forbidden to continue mining stratification. When the roof is dropped, it is forbidden to work in the adjacent or lower part of the roadway.
When the roof is collapsed, it is forbidden to use the felling method to withdraw the pillars. When the first layer is mined, it is forbidden to withdraw the pillars.
For the gently inclined ore body whose roof cannot be collapsed naturally in time, it should be forced to ceiling.
Rock drilling, charging, mining and other operations should be carried out in the support area.
After the mining area is finished, a reinforced false roof should be laid at the entrance of the patio.
Mining should be carried out from the side of the nugget to the direction of the patio to avoid a poorly ventilated single working face. When the excavation approaches the patio, the stratified veins (the veins) must communicate with the other patio within the stratification.
To clean the work surface, it must start from the exit to the caving area.
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