Shandong Gold Ridge iron ore is located in Zibo City, is a medium-sized mine has a long history of mining, Jinling Iron current annual extraction volume reached 1.5 million t, of Iron Mountain, Zhaokou, Hou Zhuang, Wang Zhuang composed of mining and other production . Since the conversion from open pit mine to underground mine in 1970, the comprehensive method, shallow hole retention method, sublevel caving method and section rock drilling stage mining method have been adopted successively, in which the staged rock drilling stage is applied. The ore produced by the house method accounts for about 70% of the total mined. The ore bodies in the mining area have different morphological forms, with a dip angle of 10° to 70° and a thickness of 2 to 50 m. The shapes are layered, lenticular, and lenticular. The deposit is contacted with skarn type magnetite, the density is 4t/m 3 , the hardness is f=8～10, the upper plate is Ordovician limestone, f=8～10, the lower plate is diorite , f= 10～12, there is an uneven distribution of skarn zone between the ore body and the diorite. The boundary of the ore is clear and moderately stable. The inclined or steeply inclined ore body with 10~15m and upper middle to thick thickness is mining in the staged rock drilling stage. The structural parameters of the mining house are basically not more than 3300m 2 according to the exposed area of ​​the surrounding rock, and the exposed area of ​​the roof is not more than 800m. 2 left. After decades of practice and scientific research, the Jinling Iron Mine has matured its use in the sectioned rock drilling stage mining method for medium to thick and steeply inclined ore bodies.

I. Low-stage stage

At the beginning of the Jinling Iron Mine, this method is used to mine medium and thick ore bodies. The method is characterized in that the ore blocks are divided into mine houses and pillars. The bottom structure of the flat bottom receiving ore and the lower double lane plus connecting channels is used in the mining room. The cutting vertical channel and the cutting patio are combined with the vertical deep hole drawing method, the mining is carried out in the staged rock drilling stage, the working surface is vertically arranged, the mining mode is blasting by row, and the waste space is filled with waste rock and tailings.

(1) Structure parameters of the nugget

The height of the development stage is 40-70m, and the height of the section is 12~14m. When the mine is arranged along the strike, the length of the mine is 40-60m, the width is the horizontal thickness of the ore body, the column is 6m, and the top and bottom columns are 8m. When the mine is vertically oriented, the width of the mine is 20~25m, and the length is The horizontal thickness of the ore body is 8~10m wide and the thickness of the top column is 8~10m. The BBC-120F or YGZ-90 rock drill is used to form a fan-shaped medium-deep hole in the section rock drilling roadway. At 4 to 18 m, the hole diameter is Φ65 mm. The selected blasting parameters are 1.5m row spacing, hole bottom distance 1.8～2.2m, blasthole density coefficient 1.2～1.4; manual loading 2# rock ammonium ladder block explosive or chargeer powder, charge density is 3.0kg /m, the detonating cord is detonated.

(2) Approved cutting engineering layout

The mining work includes excavation of pedestrian equipment wells, sectional contact roads, cutting roadways, cutting back wind uphills, rock drilling flats, rock ore slipping wells, etc. The use of the extra-pulse lower-panel pedestrian equipment well and the extra-pulse outlet section to contact the flat lane alignment arrangement. The pedestrian equipment well is arranged in the lower part of the ore body, the inclination angle is 45°, and the spacing is about 200m; the sub-distribution of each sub-section is parallel to the direction of the ore body and the communication roadway is connected with each mining room; the slip mine is also arranged in the ore body The lower plate has an inclination of 55° or 90° and serves to dig and pour the miners with a spacing of less than 100m.

The mining roadway firstly cuts into the equipment wells by cutting up the mountain and returning to the wind uphill side. After the upper stage is connected, the initial ventilation system is formed. At the same time, the sectioning well is drilled, and the mining system is formed as soon as possible, and then the tunneling of the section roadway is started. Beginning with the upper section, the first step is to pass through the slippery well, and the boundaries of the orestones are explored in detail to guide the tunneling of the subdivision tunnel. The 7555 pneumatic rock drill is used for rock drilling, and the gold-WJD-0.75 electric scraper is used for excavation. The waste rock is not discharged from the well and is used as a filling filling filling area. The basic mining and cutting engineering layout is shown in Figure 1.
Figure 1 Jinling iron ore section rock drilling stage mining method

1--shooting retreat; 2-mining approach; 3-pulse outer lane; 4-cut patio;

5-rock drilling roadway; 6-person equipment well; 7-ore slipping well; 8-transportation alley; 9-slipping alley

(3) Mining work

The cutting groove is used as a free surface, and the hole blasting is performed. Starting from the upper segment, the rupture operation is performed in a trapezoidal downward section. Each time blasting 1 to 2 rows of blastholes, the special conditions are determined according to the ore-mining conditions. The upper and lower sections maintain the lead distance of the 2 rows of blastholes to ensure the safety of the upper section blasting operation. The falling ore is borrowed from the ditch at the bottom of the mine. The gold-WJD-0.75 electric scraper is used to transport the ore to the slip or directly into the mine car. The large ore is crushed in the alley.

Second, the high-segment stage mining method

With the increase of mine output and the requirement of lowering mining cost, the shortcomings of the low-segment medium-deep-hole stage mining method are becoming more and more obvious. For example, the section height is small and the number of horizontal sections is large, resulting in a large amount of mining block mining. The cutting capacity is 75m/million, the preparation time of the mine is long; the amount of deep hole collapse per meter is small, about 4~5t/m, the blasting efficiency is low, the cost of drilling rock is high; the mining parameters are small, the pillar The ore ratio is significant and the ore recovery rate is low. Therefore, after research and demonstration, the Jinling Iron Mine changed the stage mining method from the low segment with a segment height of 12 to 14 m, which was generally used, to a high segment of 18 to 20 m and a maximum of 26 m (Fig. 1). .

(1) High segmentation blasting parameters

The original low-stage medium-deep phase mine blasting parameters have not been adapted to the blasting requirements of the same-stage deep-hole mining. Therefore, the original blasting parameters are improved. In order to ensure the blasting effect, the cutting alley and the cutting patio/uphill are combined. In order to reduce the clamping property of the blasting method, the width of the groove is increased from 3m of the original low-segment deep hole to 5-6m, and the comparison of the blasting parameters of the two arrangements is shown in Table 1.

Table 1 High-segment and low-segment stage mining room method parameters
Mining method
High-segment stage mining method mining house
High-segment stage mining chamber
Low-segment stage mining method mining house
Low-segment stage mining chamber
Row spacing / m
Hole bottom distance / m
Borehole density factor
Charge per metre of gun hole / kg
Charge factor
Borehole diameter / mm
Pull groove width / m
2.0 to 2.5
2.5 to 3.0
1.5
7.0 to 7.58
0.8
100
1.2 to 1.5
1.5
1
8.0~8.5
0.9
100
5~6
1.5
1.8 to 2.2
1.2 to 1.4
3.0
0.8
60/65
1.2
1.5
1.2
5.0
0.9
60/65
3

(2) Rock drilling equipment

Replace the YGZ-90 medium-deep hole drilling rig with KQJ-100B DTH drilling rig . The drilling rig is not only easy to operate, but also has low noise and flexible use. The rock drilling quality is reliable and efficient. The cost of drilling rock is low and can be drilled. Φ100mm, deep hole with a depth of 30~60m. The comparison of the working performance and technical and economic indicators of the two types of drilling rigs is shown in Table 2.

Table 2 Working performance and technical and economic indicators of two types of drilling rigs
Rig model
KQJ-100B
YGZ-90
Drilling diameter / mm
Rock drilling type (f)
Maximum depth / m
Use wind pressure / MPa
Use water pressure / MPa
Air consumption / (m3 / min)
Applicable roadway (width × height) / m
Monthly efficiency / m
Class effect / m
Drill cost / (yuan / m)
Drill pipe cost / (yuan / m)
Impactor cost / (yuan / m)
Labor fee / (yuan / m)
Other / (yuan / m)
Total cost / (yuan / m)
80～130
8~16
Up 60/down 30
0.3 to 0.7
0.8 to 1.0
12
2.8×2.8
1200
20
1.12
1.11
1.24
6.97
10
20.44
50-80
8~16
30
0.3 to 0.7
0.4 to 0.6
<12
2.8×2.5
1200
20
0.50
1.41
6.97
10
18.88

(3) Charge equipment and explosives

The pressure-transporting charge is used, and the viscous granular emulsified ammonium explosive is selected to increase the viscosity and reduce the amount of powder returned, thereby ensuring the charge density. The charging equipment uses BQF-100 type charger. The charger has 2 kinds of drug delivery tubes with diameters of 25.4mm and 32mm respectively. Use the 25.4mm drug delivery tube in the mining area where the low-segment medium-deep hole continues to be used. The use of a 32mm drug delivery tube in the high-section mining area is more flexible and avoids repeated investment.

(4) Detonation method

It adopts high-precision detonating tube hole bottom detonation, millisecond micro-differential section blasting, and implements internal section blasting, which is generally 1 hole and 1 section to reduce the damage of blasting shock wave and ensure good blasting effect.

Third, the stage rock drilling stage mining method technical and economic indicators

The main economic and technical indicators of the two layouts of the sectioned rock drilling stage mining method adopted by Jinling Iron Mine are shown in Table 3.

Table 3 Main economic and technical indicators of the mining method in the staged rock drilling stage
Mining method
Low-segment medium-deep phase stage mining method
High-segment deep-hole stage mining method
Production capacity / (10,000 t / month)
Recovery rate /%
Depletion rate /%
Drilling class efficiency / [m / (台台·班)]
Collapsing amount / (t / m)
Mining cutting capacity / (m / 10,000 t)
Explosive total unit consumption / (kg / t)
Production cost / (yuan / t)
0.8
70
17
20
6.5
63～75
0.594
62
0.9
85
17
20
10~11
42~55
0.587
58

Fourth, the comparison of the two arrangements

(1) The high-segmented ore block has a low pick-up ratio. After the stage mining method was changed from low to high, the practice proved that the high-segment stage mining method effectively reduced the number of sections, and the amount of ore excavation was correspondingly reduced. The mining ratio was 75.35m/ The 10,000 t dropped to 43.58 m / 10,000 t, which significantly shortened the mining block timing and reduced the cost per ton.

(2) The effect of high-stage blasting is obviously improved. On the basis of the original low-segment deep hole, the high segmentation uses new blasting parameters, which increases the blast hole spacing and hole bottom distance, which not only reduces the amount of rock drilling in the stope, but also makes the deep hole collapse. The amount of ore is increased to 11t/m, the amount of blasting is increased, and the blasting block is moderate, the blasting quality is obviously improved, and the secondary crushing workload is reduced, which correspondingly increases the effective working time of the shovel and design. The recovery rate increased from 77% to 85.5%.

(3) Low-segment drilling is easy to control. When the deep hole and the medium-deep hole exceed a certain depth, the blasthole will be deflected in the plane and in the vertical plane, and the greater the depth of the blasthole, the more severe the deflection. Low-segment drilling medium-deep boreholes are generally within 20m. For relatively high-segment, the borehole deflection is small, the quality of the drilled blasthole is higher, and it is easier to control the changed ore body, especially for the boundary of the rock. Clear, the shape of the ore body changes greatly.

V. Conclusion

The mining method in the staged rock drilling stage has obvious advantages such as high recovery intensity, high labor productivity, low mining cost and safe mining operation. This mining method is the main mining method of Jinling Iron Mine. The research, exploration and improvement of several generations of Jinling Iron Mine have been developed from the initial low-stage stage mining method to the current high-segment stage mining method. Now the design, application and process technology of this mining method All of them are mature, and the experience of using this mining method can be used for reference.

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April 30, 2023