According to the preliminary design, a mine has built a transportation system for the east (including the south and north mining sites) and the west two open pits. Both mining sites use road development and automobile transportation. The average transportation distance has exceeded 4km, and the driving height difference is about 150m. If we continue to use a single car transportation, as the stope extends downward, the ore rock transport distance will increase year by year, and the transportation cost will rise sharply, seriously affecting the safe and economic production of the mine. Therefore, the use of the car- crusher -tape joint transportation system in the deep part of the stope is imminent.
1 tape transport system introduction
The preliminary design of the mine has arranged 5 sets of tape transportation systems in the east and west mining sites. There is a set of ore belt transportation system in the West Stope. It is located in the section of the E-slope of the South Section of the stope. It consists of the former chute, XKC flat belt machine, XK2 inclined well belt machine, late slip, XK1 and XK2 inclined well belt machine. The mouth elevation is 1614.40m; the first set of rock tape transportation system is located in the B side slope of the north side of the stope, and the side belt XYI3 extends from the north end of the north end of the mining center to the southwest end of the road to the 1440m platform in the stope. XYI2 tape machine connection, XYI2 tape machine is connected with the side belt conveyor XYI1 at 1428m platform, XYI1 extends to the east end of the 1248m platform to the east end; the second set of rock tape transportation system is located in the south side E slope section, side help tape The machine XYII1 extends from the 1616m at the west end of the south side of the stopway to the northeast to the 1392m platform in the stope. The East Stope has a set of ore belt transportation system, which is located in the E-slope section of the South Section of the stope. It consists of a slip well, DK1 and DK2 inclined well belt machine. The upper part of the material mouth elevation is 1617.40m; a set of rock tape transportation system is located in the mining area. At the east end of the field, the H slope is divided into sections, and the belt conveyor DY1 is arranged at the eastern end of the north stop. The bottom elevation of the belt conveyor is 1469m, and the final unloading height of the rock is 1488m. The original design tape transport system layout is shown in Figure 1.

2 problems in the original design tape transport system

In 2013, the mine has geological conditions such as rock type, structure and structural characteristics of the slope in the open pit slope, unfavorable geological phenomena such as landslides, collapses and fault fracture zones developed by the slope rock mass, and hydrogeology of the stope. The engineering geological survey and stability study were carried out, and it was found that the B-slope section 8-12 lines above 1396m, the 12-19 line above 1224m and the 19~24 line over 1260m stage have the possibility of composite failure, while the west stop field A set of rock tape transportation system passes through some of the above areas and is in an unstable state. The slopes of other ore belt transportation systems are relatively stable. Therefore, it is important to change the position of the first set of rock tape transportation system in the West Stope.
3 tape transport system location selection program
3.1 Scheme 1
The geological survey and stability study of the mining slope of the mine pointed out that the overall slope of the north side of the west stop has the possibility of composite failure, and the stability of the slope can only be achieved by changing the mining design. According to the calculation results of the slope angle sensitivity analysis, when the B-slope section 8-12 line is above 1396m, the slope is slowed to 42°, the 12~19 line is more than 1224m, the slope is slowed to 43°, and the 19~24 line is more than 1260m. When the slope slows down to 43°, the slope can reach a steady state. Therefore, the solution does not change the position of the tape system, but the above-mentioned potential unstable region of the B slope is expanded according to the final slope angle and the step slope angle recommended in the slope stability study. Finally, the 12th to 19th lines are extended to the north by 65m, resulting in a final slope angle of 60° for all steps above 1224m, and the stage slope is slowed to 43°; the 19th to 24th lines are extended to the north by 87m, resulting in the final edge of each step above 1260m. The slope angle is 60° and the stage slope is slowed to 43°. After calculation, the program increased the amount of rock stripping by 32.639 million tons, which was taken as the infrastructure for rock stripping. After the boundary expansion, the position B slope of the first set of rock tape system reached a steady state, and the system was stable.
3.2 Option 2
Due to the possibility of compound failure in the overall slope of the North Side of the West Stope, this program changed the installation position of the first set of rock tape transportation system in the West Stope to the west side of the West Stope. After the change, when the west mining field enters deep mining, the rock in the stope adopts two sets of cars—semi-mobile crushing station—the side help tape machine—the dumper transport system. The first set of belt conveyor system is arranged in the west side of the stope. The side belt XYI5 extends from the 1600m north end of the west side of the stop to the southwest to the 1476m platform in the stop. The XYI4 belt conveyor is connected by the transfer facility. The XYI4 belt machine is at 1440m platform. The XYI3 tape machine is connected with the side belt conveyor XYI3. The XYI3 belt machine is connected with the side belt conveyor XYI2 at the 1416m platform. The XYI2 belt machine is connected with the side belt conveyor XYI1 at the 1368m platform, and the belt conveyor XYI1 extends to the northeast of the stop. The west end of the stope is 1248m platform. The second set of tape transportation system is located in the south side slope section, and the belt conveyor XYII1 extends from the 1616m at the west end of the south side of the mining field to the northeast to the 1392m platform in the stope. Scheme 2 tape transport system layout is shown in Figure 2.

The modified rock tape system of the West Stope is located in the A, B, and E2 slope sections. After analysis, the XYI1～XYI5 rock side help tape system does not pass through the unstable area of ​​the B slope. The A and E2 slope sections are in a stable combination relationship, and there is no fault passing. Therefore, the rock tape transportation system is in a stable state.
3.3 program comparison
3.3.1 Technical comparison
Scheme 1 needs to be expanded, the amount of rock stripping is increased more than the original design, the capital investment is higher, the production organization is difficult; the belt transport distance is long, and the car transport distance in the pit is short.
In Scheme 2, the roads in the pit changed, the amount of rock stripping was reduced compared with the original design, the capital investment was low, the production organization was convenient, the belt transportation distance was short, and the car transportation distance in the pit was long.
3.3.2 Investment comparison
The expansion and stripping amount of the scheme 1 is taken as the infrastructure rock-peeling treatment. The difference between the investment costs of the two schemes is mainly reflected in the cost of expanding the rock stripping, the cost of dumping the farm, the cost of road reconstruction and the investment cost of the belt machine construction. After calculation, the investment in Option 1 is more than 502.34 million yuan compared with Option 2. The comparison of the two scheme investments is shown in Table 1.

3.3.3 Business Comparison
Because the configuration, transfer and system traffic of the two schemes are basically the same, only the differences in rock weighted distance and operating cost are compared. According to the planned mining schedule, the static comparison results of the two schemes are shown in Table 2.
In summary, it can be seen that, firstly, in terms of operating costs, Scheme 1 has certain advantages in the early stage of the tape system being put into use due to the short rock transportation distance in the stope, and this advantage will gradually weaken after the peak period of stripping. Secondly, due to the need for expansion of the scheme 1, the boundary of the mining site of the 12~24 exploration line of the west side of the stope has been expanded to the north, resulting in the formation of some soil and road sections on the north side of the stope. Within the realm of the situation, it needs to be cleaned up and rebuilt, so that the difficulty of production organization and the capital investment cost of the scheme 1 are higher than that of the scheme 2; again, the tape system selected by the scheme 2 is located at the west end of the west mining field, belonging to A , E2 slope division, these two slopes have no large faults, and the slope stability is better.
Based on the above reasons, it is considered more reasonable to change the position of the west side of the west side of the stop rock to the west end of the stop.

4 Conclusion
Based on the increasing average vehicle transportation distance of the ore mining in a mine, the economic irrationality, according to the engineering geological exploration and stability research results of the exposed mining slope, combined with the actual situation of the mining site, optimize the position of the original design tape transportation system, avoiding The establishment of unstable slope areas, built in a safe and reliable rock body, has a positive significance for the mine to achieve safe, stable and efficient production.
Article source: "Modern Mining"; 2016.10;
Author: Zhou Rui; Institute of Mining and coal Inner Mongolia University of Science and Technology; Baotou Steel Group Mining Institute;
Zhao Yajun ; School of Mining and Coal , Inner Mongolia University of Science and Technology;
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