The blasting quantity at one time is large, the blasting times and the blasting avoidance time are reduced, and the utilization rate of the stope equipment is improved The broken quality of ore and rock is improved, Mining Drilling Equipment , and the large block rate is reduced by 40% -50% compared with the single-row hole blasting. The efficiency of perforating equipment is increased by about 10% -15%, which is due to the increase of working time utilization factor and the decrease of the number of operations of perforating equipment and filling area after blasting. Improve the efficiency of mining and transportation equipment by about 10% -15%. 5. Multi-row hole differential extrusion blasting method It refers to the multi-row millisecond blasting in the case of residual muckpile in the working face. The existence of the muck pile creates conditions for extrusion. On the one hand, it can prolong the effective action time of blasting and improve the utilization of explosive energy and crushing effect; on the other hand, it can control the width of the muck pile and avoid the scattering of ore and rock. The millisecond interval of multi-row hole millisecond extrusion blasting should be 30% ~ 50% longer than that of ordinary millisecond blasting, and 50 ~ 100ms is often used in open-pit mines in China. The advantages of multi-row hole millisecond extrusion blasting are as follows: (1) The ore rock crushing effect is better. This is mainly because the front is blocked by the slag heap, and each row of boreholes, including the first row, can increase the charge and be fully crushed under the extrusion of the slag heap; (2) The muckpile is more concentrated. For mines using railway transportation, the road can not be removed before blasting, so as to improve the efficiency of mining, loading and transportation equipment. The disadvantages of multi-row hole millisecond extrusion blasting are that the consumption of explosive is large, the working platform is required to be wider to accommodate the muck pile, and the height of the muck pile is large, which may affect the safety of excavator operation. III. Blasting measures near the slope With the downward extension of open-pit mine, the problem of slope stability has become increasingly prominent. In order to protect the slope, the blasting near the slope should be strictly controlled. According to the experience at home and abroad, the main measures are millisecond blasting, presplitting blasting and smooth blasting. 1. Adopt millisecond blasting to reduce vibration One of the main functions of millisecond blasting is to reduce the seismic effect of blasting. In order to give full play to the shock absorption effect of millisecond blasting, the key is to try to increase the number of blasting segments and control the millisecond interval. 2. Adopt presplitting blasting to isolate the slope. The presplitting blasting near the slope is to drill a row of dense parallel boreholes along the slope boundary, fill each hole with a small amount of explosives, and detonate before the excavation zone is blasted, so as to obtain a crack with a certain width and running through each borehole. Due to the separation of the excavation zone from the slope by the pre-fracture, the seismic wave of the subsequent excavation blasting will produce a strong reflection on the fracture surface, which will greatly reduce the seismic wave passing through it, thus protecting the slope. 3. Adopt smooth blasting to protect the slope. Smooth blasting near the slope is to drill a row of dense parallel boreholes along the boundary line, fill a small amount of explosives in the holes, and then blast after the excavation of boreholes, so as to form parallel rock walls along the dense boreholes. The difference between smooth blasting and presplitting blasting lies mainly in the initiation time. The initiation of the smooth blasthole is later than that of the previous rows of excavation holes, usually 50 to 75 ms later. In addition, another measure is to control the blasting of the last few rows of boreholes. The explosive quantity and resistance line of the last rows of boreholes near the slope should be reduced, which is called “buffer blasting”, which can reduce the damage of drilling blasting to the slope. IV. Purchase, loading and transportation Mining and loading operation is to use loading machinery to excavate ore rock directly from the ground or blasting pile, and load it into the carriage of transport machinery or unload it directly to the designated place. It is the central link in the process of open-pit mining, and other production processes such as drilling and blasting, transportation and so on serve for mining and loading. Main mining and loading equipment: excavator, dragline, hydraulic shovel and rubber-tyred front loader. In the process of open-pit mining, the capital construction investment of mine transportation accounts for about 60% of the total investment of mine capital construction, and the transportation cost and labor volume account for more than half of the total ore cost and labor volume respectively, which shows the important position of transportation in open-pit mining. Transportation modes of open-pit mines: automobile transportation, railway transportation, belt transportation, slope skip lifting transportation and combined transportation, among which dump truck transportation is the most common. Mining and transportation are inseparable, and they influence and restrict each other. At present, the development trend of mining and transportation technology is mainly reflected in the large-scale of mining and transportation equipment, the integration and continuity of mining, loading and transportation links, and computer automation. 5. Rock discharge Rock dumping is the operation of the transport terminal, which transports the stripped topsoil and waste rock to the waste rock yard for disposal. Rock dumping process: rock dumping by railway transportation, road transportation and belt transportation 6. Dump Waste dump (waste rock dump): a place where stripped materials are piled up, which refers to the place where mining wastes are discharged in a centralized manner. According to the stacking sequence, the dump can be divided into single-bench dump, covering multi-bench dump and slope-pressing multi-bench dump. The dump is mainly divided into road transport dump, railway transport dump, belt transport dump and hydraulic transport dump according to the dumping process. Source: Mining Engineering Disclaimer: The content contained in this article is online information, and the copyright owner cannot be contacted. If there is infringement in the text and pictures of the article,dth drilling hammer, please contact the public number operator, WeChat ID: zjks2016, and we will delete it! Return to Sohu to see more Responsible Editor:. wt-dthtools.com
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