0 preface
Where lead-zinc mine mouth twists and expansion in 2009 after lead-zinc ore daily processing reached 5500t, annual output of 180 000 t of lead and zinc metal volume of the highest yield, after years of 180,000 t mining, mining resources less and less, especially The thick ore body in the underground is drastically reduced. At present, the remaining ore bodies are mostly top, bottom and inter-columns, as well as small ore bodies in the remote areas. It is more and more difficult to recover from the stope, and when the mining field recovers during the mining process. Occasionally, it is easy to cause injury to personnel and equipment. Fankou Mine is currently actively exploring the control measures to deal with the fall of the stope.
1 stop field
From the statistics of the occurrence of caving and mining in recent years, there are mainly VCR large blasting stope, gently inclined ore body stope along the strip and bottom pillar stope; VCR large blasting stope is mainly for side-supporting The delamination of the body along the tectonic plane and the fault of the filling body are mainly caused by the landslide of the gently inclined ore body along the strip, and the landslide of the surrounding rock is mainly dominated by the detachment of the surrounding rock. The bottom column is mainly for finding the side. In the process, the roof ore body is generally collapsed or the bottom column filling body is delaminated and collapsed. Among them, the VCR large blasting stope accounts for a large proportion of the mining volume of the Fankou mine, and the annual returning ore volume is about 450,000 tons. Therefore, the VCR large blasting stop is also the most frequent stoppage of the occurrence of the fall phenomenon. Table 1 lists several occurrences of the occurrence of the mine in recent years.
2 Analysis of the causes of the fall of various types of stope
2.1 Causes of the bottom column stoppage
(1) After the mining of the upper and two sets of mining ore bodies, the overall structure of the original ore body of the ore body is destroyed, which reduces its stability. When the bottom column is harvested, the exposed space of the stope is taken after cutting and finding the side. When it becomes larger, the ore body is easy to delaminate and fall under its own weight.
(2) The ore structure of some stope is poor, containing many small tectonic planes and small faults, which are easy to cause caving.
(3) Some of the stope has water seepage, and the water easily penetrates into the contact surface between the ore body and the filling body, which is easy to cause the roof to help fall.
(4) After the topping of the stope is completed, the roof filling body is completely exposed. If the first layer of the original upper section is recovered, the grounding grid is unqualified, the quality of the first layer of filling body is not up to standard or the one-time filling thickness is not in accordance with the technical requirements, so that the filling body integrity Poor structure, easy to cause the filling body to detach and fall.
2.2 Reasons for the fall of the mining site in the gently inclined ore body along the strip
(1) The surrounding rock of some of the gently inclined stope is a thin layered structure. When the blasting is completed, the exposed space after the shovel is enlarged, and the surrounding rock is destroyed when it is shot and shot, which is easy to cause off. The layer fell.
(2) The shape of the stope top is not well controlled, and a negative stern is formed near the rock side of the upper plate, which is easy to cause under the action of self-weight.
(3) There is water seepage in the stope, and the water penetrates into the interface of the upper ash and the ash, so that the adhesion is weakened, and it is easy to cause the upper plate to fall along.
2.3VCR large blasting stope
(1) There are obvious structural belts in the west or the two gangs of some mining houses. After the blasting, the expansive space is large, and the ore rocks in the tectonic surface are easy to slide down to the empty field, causing the west or side to fall.
(2) When some mining houses are harvested, the control is not good, and there are super and under-extraction phenomena, which makes the two-pack filling body uneven. After the blasting of the column, the two-pack filling body is exposed, which easily causes the filling body to fall.
(3) Some stope structure broken ore containing pyrite and more small faults, blasting vibration by impact, easily lead to caving.
(4) Some of the stope has water seepage phenomenon, and the water penetrates into the structural surface, which reduces the bonding force between the structural faces, and easily causes the top plate to help fall.
3 fall control measures
(1) Strengthen the treatment of the accumulated water around the stope to prevent the accumulated water from penetrating into the stope through the structural belt.
(2) When designing the blasting of the stope, it is necessary to control the single consumption of the explosive should not be too high, and try to control the total amount of blasting. For the critical surface of the stope (cutting surface or filling side), smooth blasting technology is required to reduce the impact of blasting vibration.
(3) When picking up the stope, do a good job of controlling and controlling the top work, and the picking shape of the stope should meet the design requirements as much as possible.
(4) The first floor of the stope must be filled in strict accordance with the requirements of the first layer filling, including the requirements of grounding and one-time filling thickness, and establish a strict acceptance system.
(5) Strict control of the height and width of the VCR large blasting stope, requiring the design height of the stope to be controlled within 30m.
(6) VCR large blasting stope should fully consider the mutual influence between the stope, the adjacent stope must be separated by a certain distance, and the adjacent stope with only one stop should not be arranged for simultaneous blasting.
4 safety precautions
(1) For the bottom column and the gently inclined ore body stope, try to use small trolleys to recover, manually drill the small section into the bottoming lane, effectively control the exposed space of the stope, and then use the small trolley to play the fan-shaped hole and retreat side collapse, and The use of a remote-controlled scraper to match the mining, fundamentally eliminate the risk of human work.
(2) According to the actual situation of the stope, develop a safe and reliable mining plan on site, install spotlights to enhance the stope lighting, and observe the change of the stope at any time. For the stope where the structure is prone to fall, special personnel management and shovel should be designated. Mine operations, no change in the middle of the road, in order to know the ground.
(3) The lower remote control chamber of the VCR large blasting stope must be constructed according to the specified safety distance, and the remote control personnel must be ensured to be safe.
(4) For the stope where the fall has occurred, it is necessary to immediately suspend the stop operation, reorganize the safety and technical department personnel to formulate the mining plan on the spot, and designate the responsible person in charge of the safety to shovel the site until the safe mining is completed.
(5) For the stope where a large fall occurs, it is necessary to organize safety, technical and other departments to hold an analysis meeting, analyze the cause of the fall, and propose preventive measures.
5 Conclusion
Regarding the current mining technology and mining technical conditions of Fankou Mine, it is impossible to completely avoid the fall of the stope. Only by adopting effective control measures and preventive measures, the stoppage of the stope can be controlled and reduced. Departure, analyzed several main types of landings in Fankou Mine, found out the main reasons leading to the fall of all kinds of stope, and proposed targeted control measures and preventive measures, hoping to collect for Fankou Mine. Field mining control provides a reference to reduce personnel and equipment injuries.
references:
[1] Huang Peisheng. Mining method and application status of Fankou lead-zinc mine [J]. Mining Research and Development, 2001, 21(4).
[2] Lu Zhen, Jiang Xinjian. Analysis on safety technical measures for mining of Fankou lead-zinc ore body [J]. Mining Technology, 2007, 7(1).
[3] Xiong Wansheng, Dai Zhou, et al. Groundwater comprehensive treatment and land reclamation in Fankou deposit, Guangdong Province [J]. Guangdong Geology, 2001 (2).
[4] Ji Zhaoning, Huang Guangzhu. Application status of approach mining method in China [J]. Mining and Metallurgy, 2000 (1).
[5] "Mining Handbook" writing group. Mining Manual [M]. Beijing: Metallurgical Industry Press, 1990.
Source: Mining Technology: 2016, 16(4);
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