Discussion on the application of the comprehensive method of flat-bottom structure retention in the Makeng mining area

0 Preface

With the vigorous development of the mining industry and the improvement of mechanized operations, some of the original mining methods have been further enriched and improved in the production process. Based on the mining design of the 390 middle section of the Makeng mining area and the technical guidance experience on the site, the design and application of the comprehensive mining method for the remaining mine is further explored.

1 Characteristics of the Ma Hang Deposit

Fujian Ma Hang iron ore mine is a large body buried magnetite ore body mainly occur in the unconformity surface of Nanjing Qixia Formation sandstones and limestones, bedded output. The ore body is generally NE, tending to NW, and the inclination is 20°-50°. Due to the influence of post-mineralization faults, the ore body is cut into multiple sections, and the occurrence and occurrence state of each section of the ore body changes greatly. The Makeng mining area is currently divided into one and two stages of mining. The main ore body of the middle section of the first-stage mining area is about 1600m long and extends 620-1080m. The average thickness is 870m, the maximum thickness of the ore body is 101.72m, the average is 21.76m, the height of the reservoir is +600m-120m (the hole of 71 line 68), and the depth from the surface is 40-700m.

Of roof rock ore mainly skarn and marble, floor rocks are mainly skarn and sandstone, with stone main skarn, sandstone, angular rock gangue minerals garnet, diopside-based , followed by calcium iron pyroxene, Fushan stone, quartz , amphibole, are hard rock. The ore is mainly his grain-like structure, and the ore structure is mainly disseminated and block-shaped.

2 Brief description of the comprehensive method of staying in the flat bottom structure

The comprehensive method of flat-bottomed structure retention is the mining method combined with the flat bottom structure and the comprehensive method of retaining ore, as shown in Figure 1. The trackless shovel equipment is put into use in the mine production process. The original bottom structure of some bottom pillars is gradually replaced by the flat bottom structure, which makes the mining block mining and cutting more economical and simple, and the ore arching, The clogging phenomenon has been significantly improved, the shovel loading efficiency has been significantly improved, and the production capacity of the mine has been greatly enhanced.

Figure l Flat bottom structure retention method

Fig. 1FuIlshrinkagemethodwith. Flat, a bottomstructure

3 mining process

3.1 nugget components

Considering that the ore body of the first-stage ore section of the Makeng mining area is a veined vein ore body, the ore body has a dip angle of 20°-50° (which is a gently inclined to inclined ore body), and the ore body has a large change in occurrence and occurrence. The ore block is arranged along the ore body. The length of the ore block is 50m, the width is the thickness of the ore body, the stage height is 30m, the top column thickness is 5m, the column width is 5m, and the temporary pillar size is (4-5)m×( 4-5) m.

3.2 mining cutting

3.2.1 Mining block mining

The mining block mining projects mainly include: mining block transportation lanes and cross lanes, loading and unloading roads, mine pedestrian ventilation ducts, and communication roads. The mining block is mainly determined by the order of the stage transportation level. At present, the level-level mining methods are mainly in the form of simple mining and joint mining. The joint mining is suitable for thick and multi-vessel ore bodies. When the transportation volume is large, the circular joint mining of the upper and lower flat roads and the cross-span can be adopted. Considering that the ore body of the first stage of the Makeng mining area is strip-shaped, medium-thick, gently inclined to the inclined ore body, the ore block along the ore body orientation and the stage transportation capacity requirements are large, and the stage adopts a circular arrangement.

The annular alignment arrangement is divided into two types: an intrapulmonary, an outer annular arrangement and a pulse outer annular arrangement. What kind of mining form is used in the specific work depends mainly on the stability of the roof of the ore body and the mining order of the ore block. Is it the first mining or the first mining in the upper plate? When the roof of the ore body is relatively stable, the mining sequence of the ore block It can be carried out by adopting the upper plate first or the lower plate first. At this time, the mining can also adopt two forms: inner pulse, outer annular arrangement and outer pulse annular arrangement. However, considering the problem of the safe management of the loading and unloading operation and the top management of the mining operation during the actual mining operation, in the above case, it is generally preferred to use the top plate along the vein and the pulse along the vein and the vein. The form of the inner and outer annular arrangement. When the roof of the ore body is relatively broken, the karst is developed, and the stability is poor, the mining sequence of the ore block can only be harvested by the method of mining the next plate. When it is harvested close to the upper plate, it can reserve 1-2m. The ore is used as a top column to support the broken top plate and ensure the safety of the mining operation. Its mining form can only consider the outer annular arrangement. The top, bottom and gangue minerals of the Ingakeng iron ore body are hard rock, and the ore body is a medium-thick ore body. Therefore, the inner and outer rings of the inner and outer rings along the vein and the outer vein are used. Arranged in the form of approval.

The loading and unloading route can be divided into two types: from the upper plate to the lower plate and the lower plate to the upper plate according to the different forms of the pulse inner and outer evaluation images and the outer pulse arrangement. Considering that the design is designed with inner and outer annular arrangements, the loading route is in the form of playing from the upper plate to the lower plate. From the "metal mining deposits" learned. The specifications of the loading route are generally: 3-3.2m high and 3-5m wide. The length is 8-10m, the radius of curvature of the loader is 6.5-8m, and the scraper is 9-20m. . But this design takes into account the top of the Ma Hang iron ore body. The lithology of the bottom plate and gangue minerals are all hard rock, so the new specifications are adopted in the design of the loading route. The specific dimensions are: 3.5-4m high, 10-10.5m wide and 8m long. The production process is verified, the application is ideal and safe, and it provides good conditions for the use of large-scale trackless shovel loading and transportation equipment in underground mines.

The form and arrangement of the pedestrian air duct of the mine has a great relationship with the angle of the ore body, the thickness of the ore body and the order of the mining. When the ore body is a steeply inclined ore body, the pedestrian air duct of the mine room is arranged in the form of a patio instead of The layout of the uphill mountain is mainly to save the amount of engineering. When the ore body is gently inclined or inclined ore body, it adopts the uphill form, and is arranged according to the mining order and the thickness of the ore body. When the upper plate is firstly taken and the ore body is thicker, the upper plate is adopted near the upper plate, and vice versa. When the disc is first taken, it is used to go uphill near the lower disc. It is arranged in the above manner, and the main consideration is the safe entry and exit during stratified recovery. The mine connection road is 5m, and the left and right uphill contact roads are staggered. The topmost contact road of Shangshan is arranged under the top pillar, which serves as the boundary line of the top pillar. When the mining operation reaches the contact road, the operation should be stopped. So as not to damage the top column.

3.2.2 Nugget cutting

The cutting of the ore block is divided into two types of cutting before the first plate and the first plate. The cutting of the nuggets first taken on the upper plate is developed by the approach. When the approach reaches the predetermined position, the accesses pass through each other, and then the V-groove is pulled from bottom to top until the top plate has a slope angle greater than 45°. Conducive to falling ore to slip. The mined block that was first taken in the next plate is cut. When the approach reaches the lower line, the approach is pulled along the lower line, and then the layer is pulled down from the bottom to the top.

4 mining

4.1 rock drilling

The flat-bottom structure retaining ore mining method adopts shallow hole falling mine, and the slope layered mining is carried out in the order of operation. The stratified mining height is 2m. According to the stability of the ore, the upward blast hole or horizontal blast hole is used, and the horizontal blast hole is generally used. Use a long step working face or a full working face without a step to facilitate the organization of work and reduce the time of the dome and the field. When the horizontal blasthole is used, the length of the working face of the step is 2-4m, the height is 2m, and the falling section is used for collapsing. The thickness of the ore body is large, the ore is hard, and the ore that needs to be collapsed is uniform. The holes are staggered. Arrangement parameters of the blasthole: row spacing 0.75-0.8m, hole spacing 0.75-0.8m, hole depth -4m.

4.2 Blasting

2# rock nitramine explosives are generally used. In order to prevent the uneven distribution of explosives in the blasthole, it collapses into large chunks, and the coefficient of charge of the blasthole is generally 60%-70%. The detonation uses a single ignition to detonate, and the blasting sequence should be retreated from the center to the pedestrian line.

4.3 Local ore deposit, dome flat field and secondary crushing

After the ore collapses, in order to continue to maintain the original working space height, 35%-40% of the ore must be released in time, and the ore discharge of each loading lane should be balanced as much as possible. During local mining, the loader and the planner should work closely together to carefully observe the drop of the remaining ore surface of the loaded mineway to prevent the formation of overhanging arches or voids in the retained mine. After the ore release, the working platform should be cleaned and leveled in time, and the industrial site should be prepared for the next cycle operation. At the same time, the top plate and the side support must be loosened without falling ore and surrounding rock. Can not be squatted, must also be blasted. The large blocks found in the flat field and the dome should be crushed in time to prepare the site and safety for the next cycle of rock drilling.

4.4 top board management

The mining room from the mine floor to the final mine room with the flat-bottom structure retention method is all supported by the pillars. The maximum allowable exposed area of ​​the mine space is 800-l500m. . The column between the mine and the mine is 10m wide and the top column is 5m high. The size of the temporary pillar used to support the roof is (4-5)m×(4-5)m, in the mining operation. At the end of the process, some temporary pillars can be recovered, and the remaining pillars are reserved for permanent support. For the broken roof, some small pillars can be added to support the roof during the mining process. The specific position and specifications are determined according to the specific conditions, and in the process of mining, there must be someone to track and manage the movement of the roof. To ensure the safety of mining operations.

5 Application evaluation of comprehensive method for mining of flat bottom structure

The comprehensive method of flat-bottomed structure retention has been fully applied in the production of 390 middle sections of the Makeng mining area. It has been proved by practice that the mining process of the flat-bottom structure retention method is technically feasible, economically reasonable, and safe. Its recovery loss rate is about 20%-25%, the depletion rate is about 5%, and the single mine housing production can reach 250-300 tons. Compared with the traditional comprehensive method of mineral retention, the economic and technical indicators have improved significantly.

The comprehensive method of flat-bottomed structure and retention of minerals should pay attention to several problems during the mining operation: 1) The mining operation of the upper mining first, the surrounding rock of the roof must be cleaned once in the process of mining, so as not to affect the mining operation of the lower layer. Safety; 2) The mining operation of the first mining in the lower plate must strengthen the management of the roof of the road during the operation. When there is a crack in the roof of the road, it must be processed in time to ensure the safety of loading.

6 Conclusion

The comprehensive method of flat-bottomed structure retention provides a good operating platform for underground mine mechanization operations, creating favorable conditions for the large-scale development of enterprises, and further improving the labor productivity of mines. The above is the author's design experience and on-site technical guidance work experience, only for reference and reference of similar mining and mining workers.

references

『1】Song Yongguo. Discussion on mining technology of ore block in Makeng mining area [J]. Non-ferrous metals (mine part), 2006, 58 (1): 4-5.

『2】Liu Wugang, Chen Youzhi. Geological characteristics and genesis of the middle section of Mikeng Iron Mine[J].Nonferrous Metals(Mine),2006,58(2):14-16.

"31 Zhongyi, Wu Fengmei, Chen Zhongjing, et al. Metal deposit mining [M]. Beijing: Metallurgical Industry Press, 1993.

『4】 Li Zhixin, Li Rongkun, Zhang Yushu, et al. Geology and mine geology [M]. Beijing: Metallurgical Industry Press, 1991.

"5] General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China. China National Standardization Administration Committee. Safety regulations for metal non-metallic mines (B16423-2006)

『s]. Beijing: 2006.