The inclination angle of the gently inclined medium-thick ore body is generally 15°～30°, and the ore body level is 4～15m thick. Due to the special geological structure features of the gently inclined medium-thick ore body, the mining difficulty is increased, and the mining and cutting ratio appears. Large, difficult ore transport, low recovery rate, high loss rate of depletion [1-3]. Thick orebody method gently inclined main room and pillar method [4], the approach to the filling method [5], is mainly used for room and pillar mining gypsum, potassium salt, etc. Non-metallic mineral, the approach to the filling The method is mainly used to mine precious metal deposits such as copper . This study takes a gently inclined copper ore body as an example, and introduces the application results of the large-section approach filling method in the mine in detail, which provides reference for similar mines.
1 mining technical conditions
A copper deposit is a sedimentary rock type copper deposit with a rock mass stability coefficient of 6-8. The rock mass of the ore body is slate , the rock mass is moderately stable, and the lower rock mass is metamorphic granite , medium stable-stable, ore. The body is slate, layered structure, moderately stable rock mass, the ore body inclination angle is about 25°, the ore body level is 8-10m thick, the ore body trend is about 1500m, and the copper ore grade is about 2.0%. The copper deposit adopts the joint development method of slope road and shaft. The designed annual production capacity is 1 million tons, the design middle section height is 100m, the middle section bottom column height is 20m, and each middle section is divided into 5 sections.
The section height is 16m, the main transportation lane has -200m and -300m2 transportation levels, and the middle section adopts rail transportation mode.
2 large section approach filling application
2.1 Mining process selection
In order to reduce the depletion rate of ore, reduce the damage of mining to the surrounding environment, ensure the safe and efficient mining of resources, and take into account the thickness of the ore body, the ore body design adopts mechanized approach-type horizontal stratified filling method. Due to the high height of the middle section and the long horizontal transportation distance, it is difficult to transport the ore. Five inclined long shafts are arranged in the sub-district roadway of the ore body. The ore passes through the slanting well to the main transportation level and is transported to the ore unloading station by rail transportation.
2.2 ore body mining cutting and mining
The mining body is cut as shown in Figure 1.

(1) The mining block is approved. The main slope of the ore body is arranged in the lower part of the ore body, and the slope road is connected with each section of the roadway or the middle section of the roadway. The designed nugget is 60m long, the width of the nugget is the thickness of the ore body, and a permanent isolation column of 3~4m thick is reserved between each nugget. Excavation and construction of rock drilling rigs for mining construction, the section size of the roadway is 4m×3.8m, firstly the lower part of the construction
Duan Pingxiang, then the construction of the 45m horizontal contact roadway perpendicular to the lower section of the section of the road, and through the ore body.
(2) Ore mining, handling and filling. After the contact road of the stope passes through the ore body, the drilling section is used to drill the section of the mine with a section size of 4m×4m, and the scraper is used to transport the ore to the main chute of the ore body, and the tunnel is digging into the mine. The block permanent isolation column is stopped, thus completing one layer of recovery. After the ore is harvested, the contact road 02 is pressed, and then the top of the stop is filled. During the filling process, the three-way hose is used to fill the top plate. After the filling is completed, the blasting is carried out on a layer. The cycle is continuously taken.
(3) Ventilation of the stope. The stratified roofs of the stope are filled, and the natural gas in the stope cannot be naturally ventilated. The local fan must be used for forced ventilation, and the fan-injection-extraction type mixed ventilation mode is adopted.
2.3 Large section filling road design
In the process of returning the ore, the original small section approach (Fig. 2) has the following disadvantages: 1 poor technical and economic indicators, high depletion rate of small section roadway (10%~15%), and recovery rate below 50 %, the ore body is depleted and has a large depletion loss; 2 the production efficiency is low, the production efficiency per 1 heading face per shift is about 134.4t, and the efficiency is low. It can be seen that this type of small section roadway has to be improved. Through theoretical analysis and field test, the pentagon-like cross-section arrangement (Fig. 3) is determined. This type of section can significantly reduce the ore depletion rate, and the ore recovery rate can be increased to more than 65%. Increase by more than 15%.

2.4 test results

In order to determine the most suitable section parameters, according to the site geological conditions, two types of section layout schemes were tested: 16m (input width) × 4m (input high); 28m (introgress width) × 4m (high approach). In order to ensure reliable test results, the two sets of tests were selected for a moderately stable lithology stope. The test results of the large-section access road show that the scheme 1 can achieve safe and efficient mining under the auxiliary support of the anchor and the 4m long anchor cable. The rock and the roof of the upper plate do not fall, and the rock stability of the lower plate is better; 2 Despite the auxiliary support of the anchor and the 4m long anchor cable, the rock and the roof of the upper plate have fallen, and the rock in the lower plate has a slippery phenomenon, and the ground pressure is difficult to control.
3 Conclusion
Aiming at the problems existing in the mining of the gently inclined medium-thick ore body by the approach filling mining method, taking a gently inclined medium-thick copper ore body as an example, the section of the roadway filling stop is optimized. The test results show that the optimized large The section approach (6m (intake width) × 4m (high approach)) significantly reduced the depletion rate, and the ore recovery rate increased by more than 15 percentage points.
The efficiency of each shift has increased by more than 15 percentage points, with remarkable results and certain promotion value.
references
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