At present, most shallow mine resources in China are about to be exhausted or have been exhausted, and underground mining has gradually turned to deep mining. Deep mining faces complex geological conditions such as “three highsâ€. These complex geological conditions, including high stress environment and high temperature environment, will lead to higher mining costs. Some mining methods applicable to shallow mining may not solve the problem of deep mining, so it is necessary to find an efficient mining method that is more suitable for deep mining. According to the -665, -650, -635m, the cutting groove is blasted from top to bottom, and the previous segment advances the next segment 2 to 3 rows (3 to 4.5 m) until the blasting is completed. After the mining of the stope is completed, the bottom trench is discharged into the mine, and the three-segment approach takes over, and the full tail sand cement fills the goaf, which is convenient for the second step back to the mining pillar stop. Article source: Mining Technology; 2017.17(2) Author: Wang Yao; Daye Nonferrous Metals Group Holdings Co., Ltd., Hubei Huangshi 435500; Copyright: Epp Packing,Expanded Polypropylene Packaging,Expanded Polypropylene Foam,Expanded Polypropylene Block Taizhou Tianma Plastic Products Co. LTD , https://www.tztmslepp.com
After the segmentation of the empty field, the filling method is essentially a sublevel caving, concentrated mining, and finally the formation of the empty field. The mining method has certain requirements on the geological conditions and occurrence of the ore body:
(1) The ore body and surrounding rock must be medium and stable, otherwise it will lead to large-scale collapse of the stope and loss of control, causing serious depletion of ore;
(2) The layout of the mining area must be continuous, otherwise it will cause loss of ore depletion;
(3) The dip angle of the stope suitable for caving is large, otherwise the declining rate of the inclined inclined ore body is large, the loss rate of the lower plate is large, and the technical and economic indicators are not up to the requirements;
(4) The division of the ore block, if the thickness of the ore body is less than 8~15m, it is arranged along the strike; if the thickness of the ore body is greater than 8~15m, it is arranged vertically.
The segmentation empty field and post-filling method charge blasting are carried out in the rock drilling roadway. The exposed area of ​​the mining work roof is small, the stope operation is safe, the mining process is simple, the operation efficiency is high, and it has certain advantages compared with other mining methods. Conduct mining method tests for deep mining for deep mining applications.
1 a copper ore mining deep geological conditions of a copper ore mining main current number Ⅲ, Ⅳ number, Ⅺ orebody. The ore body is approaching north and south, with a total length of about 1000m. Wherein Ⅲ orebody about 350m, angle 50 ° ~ 70 °, a thickness of 6 ~ 60m, copper-containing ore to ore-based magnet, dense and hard, f = 8 ~ 12, secured to a moderate stability; followed by containing Copper marble and copper-bearing skarn, copper-bearing marble f=7～8, moderately stable, containing copper skarn f=3～6, poor stability, but mainly composed of mixed ore and copper The skarn is dense and hard, f=9～17, which is relatively stable.
The surrounding rock of the III or IV ore body is mainly marble or dolomitic marble, which is generally dense and hard, with good integrity and moderate stability, f=7~15. The ore body has complex lithology, mainly skarn, plagioclase and granodiorite porphyry. The skarn and plagioclase are moderately stable, and the granodiorite porphyry is hard and stable. The local skarnized plagioclase and granodiorite porphyry are characterized by kaolinization , serpentine petrification, soft lithology and poor stability. The test site was selected for the No. III ore body. The ore body is about 30m thick, and the ore body has a dip angle of about 75°. The upper part of the ore body is igneous rock and the lower plate is skarn. The height of the middle section of the ore body in the test area is 60m, the section height is 15m, and the test stope is arranged in a vertical direction. The test stope range is -620~-665m.
2 empty field å—£ post filling method test plan
2.1 Test plan for ore placement The thickness of the ore body in the test area is about 30m, and the test stop is arranged in a vertical direction. In the selection of the test plan, the selected test plan must be representative for later use.
(1) The test plan should be operable, the equipment is easy to construct, and it is easy to be mastered.
(2) Technical and economic indicators such as test depletion loss rate and mining efficiency are better.
(3) The technical parameters of the test should be reasonable, the block rate of the stope should be low, and it is easy to shovel.
Based on the above characteristics, the test equipment is selected to use YGZ-90 drilling rig , rock drilling aperture 65mm, pneumatic loader charging, WJD-2 electric scraper mining, rock drilling road section 3m × 2.8m.
The test block width is designed to be 8,6m. When the width of the ore block is 6m, the span of the stope is small, and the goaf of the stope is small, but the equipment is not easy to be placed, and the ore loss is large, and the efficiency is low. When the width of the nugget is 8m, the equipment is easy to arrange and the mesh arrangement is relatively uniform. High efficiency, in the management of ground pressure, try to take less early mining, after the completion of the later collapse,
A large number of rapid mining, filling as soon as possible to prevent the goaf. It is more appropriate to determine the span of 8m.
The bottom of the stope adopts the gutter mining structure, and an excavation approach is arranged every 6m. The end cutting trough position is specially arranged to arrange a tapping route to cut the rock, blast and mine to form a compensation space.
2.2 Sectional empty field post-filling method reasonable technical parameters
2.2.1 Design of Cutting Patio and Cutting Groove The position of the cutting trough is arranged on the upper part of the ore body. The design of the cutting trough should consider the safety of the construction of the cutting patio and optimize the technical indicators of the depletion loss rate. The cutting patio is constructed by YT-28 drilling rig . The section size of the cutting well should be reasonable to prevent the blasting effect of the cutting blasting rock from being too large, resulting in an unsatisfactory blasting effect. The cutting patio section is designed to be 2m×2m and the height is about 12m. The parameters should not be too large or too small. Excessively large may cause the rock blasting effect to be unsatisfactory. Too small may cause damage to the rear blasthole. The design cutting groove adopts a row spacing of 1.2m, a hole spacing of 1m, and 3 holes per row. A total of 5 rows of layout.
2.2.2 Hole network parameter design Figure 1 is a sectional hollow field mining method design scheme. The design blasting row spacing is 1.5m, and the minimum blasting hole hole angle of each row of holes is 50°. According to the previous blasting explosiveness and blasting It is reasonable to determine the bottom distance of the block test hole to be 1.5 m, and the depth of each hole is in the range of 12 to 13.5 m. The blasting adopts the bottom-bottom detonation method. The detonator device is installed in the new type of detonating bomb. The orifice is filled with a space charge, and the explosive is connected in series in the detonating cable hole. The detonating bomb is detonated and the sub-differential blasting is performed (as shown in Fig. 2). When the detonation begins, one row is blasted once, and when the blasting space is large at the end, two rows are blasted at a time.
2.3 Sectional empty field, post-filling method construction and mining sequence, segmented empty field, post-filling method, first construction of bottom sulcus structure, three-dimensional parallel construction in section rock drilling roadway, -665,-650,-635m rock drilling The roadway needs to pass through the ore body, and the construction of the -620m roadway is determined according to the blasting limit range for later filling. Then use YT-27 construction cutting patio, according to the -650,-635m construction sequence from top to bottom construction. Finally, YGZ-90 is used to construct deep holes in each segment from top to bottom. 
In the test, the deep hole was detonated after completion of the charge, and it was not completely detonated or part of the blasthole was not detonated, and there was a partial failure to form a vertical wall. To this end, after the medium-deep hole blasting, first check whether the detonating tube has detonated. If the detonating tube has detonated, it is necessary to re-wash the hole to set up the detonating equipment, and then detonate; if the detonating tube is not detonated, the detonating equipment can be set up again. Detonation; for the blasting residual eye, the construction parallel hole detonation, the hole distance is greater than 15 times the blasthole distance, and then the charge detonation, if the vertical wall still can not collapse, the wrong position can increase the number of holes to detonate.
When the mine exits in the early stage, the ore volume is adjusted according to the space after the blasting. If the space is enough for one blasting, the efficiency of the mine can be slowed down, so that sufficient ore reserves are left in the stope to support the empty area, preventing the gangs from appearing in the stope. Roofing; after the mining blasting mining is nearing the end or the blasting mining has ended, the mining site will be as large as possible to reduce the exposure time of the goaf, and prevent the goafs from falling and roofing.
3 conclusions
(1) Sub-stage empty field post-filling method is suitable for deep mining, which is safe and efficient in mining, and saves a lot of excavation engineering, low cost; simple construction process, greatly reduces labor intensity, high degree of mechanization, easy to be on site Test promotion.
(2) According to the segmental empty field method in the test plan, each time the caving amount is about 2000t, it is beneficial to adjust the production capacity, reduce the middle of the operation, and concentrate the production operation points, which is conducive to reducing the cost. For low-grade ore mining, A superior mining method.
(3) Sectional empty field post-filling method The test parameters are mostly based on the experience data of a mine. The optimum technical process parameters are selected in the test and need to be tested in the test.
(4) The nature of the post-filling method is still the empty field method. In the application range, the stability of the ore body and the surrounding rock of the upper and lower plates must be considered. Otherwise, due to the instability of the ore body, the large-scale roof of the stope will be caused to collapse. If the surrounding rock is not stable, the loss rate of ore depletion will be large, and good economic and technical indicators cannot be obtained.
references:
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Hubei Engineering Research Center for Nonferrous Metal Resources Development and Comprehensive Utilization, Huangshi City, Hubei 435500, China