Original Title: Detailed Comparison and Interpretation of 5 Common Blasting Methods in Open-pit Mining.. Editor's note: We know that open-pit mining operations mainly include drilling, blasting, mining, transportation and dumping. Blasting is a very important part of it, and the cost of blasting accounts for 15-20% of the total cost of open-pit mining. Moreover, the quality of blasting directly affects the efficiency of mining, transportation, coarse crushing and other equipment and the total cost of the mine. Today, Xiaobian will share several common blasting methods in open-pit mining and their application. Classification of blasting methods In open-pit mining, the commonly used blasting methods are as follows: Classified by blasting delay time: simultaneous blasting, second delay blasting and millisecond delay blasting. Classification by blasting method: shallow hole blasting, medium-length hole blasting, chamber blasting,mining dth bit, multi-row hole millisecond blasting, multi-row hole millisecond extrusion blasting, springing blasting, external application blasting and hole-by-hole detonation technology. Five common blasting methods Shallow hole blasting The diameter of the blast hole used for shallow hole blasting is relatively small, generally about 30-75mm,dth button bits, and the depth of the blast hole is generally less than 5m, sometimes up to about 8m. If the drill jumbo is used for drilling, the depth of the hole can be increased. Expand the full text Applicable conditions: Shallow-hole blasting is mainly used for the excavation and secondary blasting of open-pit mines or quarries, caverns and tunnels with small production scale, the treatment of new open-pit mine hills, the formation of single-wall trench transportation channels on hillsides and other special blasting. Deep-hole blasting Deep-hole blasting is a blasting method that uses drilling equipment to drill deeper boreholes as the charging space of mining explosives. The deep-hole blasting of open-pit mine is mainly the production blasting of bench. Deep-hole blasting is a widely used blasting method in open-pit mines. The depth of the blast hole is generally 15 to 20 m. The aperture is 75 ~ 310 mm, and the common aperture is 200 ~ 250 mm. Characteristic Applicable conditions: Deep-hole blasting is widely used in the production links of ditching, stripping and mining in large mines. Its blasting volume accounts for more than 90% of the total blasting volume of large mines. Classification Deep holes can be divided into vertical deep holes and inclined deep holes. Vertical deep holes are mostly pierced by impact piercers. Inclined deep holes are mostly drilled by rotary drills or down-the-hole drills. Its inclination is generally 75 ° to 80 °. Chamber blasting Chamber blasting is to place explosives in a pre-chiseled chamber and charge them centrally. There are no rules for the amount of explosives detonated each time, some of which are loaded with tens, Mining Drilling Equipment ,DHD Drill bit, hundreds or thousands of tons. Because of the large amount of blasting, it is also called large blasting. Applicable conditions: Open-pit mines are used only during the capital construction period and under specific conditions, and quarries are used when conditions permit and when the demand for mining is high. Advantages and disadvantages: Advantage 1, the preparation workload is less, and the blasting work of a large number of rocks can be completed in a short time; 2. It is suitable for rocks of various hardness, especially in places with complex terrain and is not limited by construction conditions; 3, special rock drill equipment is not needed, and a rock drill is generally use for tunneling that chamber; 4. There are no special requirements for the explosives used, and all the explosives used in deep-hole blasting can be used in chamber blasting. Shortcoming The rock drilling conditions of the tunneling operators are poor, and there are many large blasting blocks. Millisecond blasting method with multiple rows of hol In recent years, with the rapid increase of excavator bucket capacity and open-pit mine production capacity, the normal excavation blasting of open-pit mine requires more and more blasting quantity each time, so the blasting method with larger blasting quantity each time must be adopted to meet the needs of new excavation machinery. At present, multi-row millisecond blasting and multi-row millisecond extrusion blasting are the blasting methods with a large amount of blasting at one time in China. These two methods can blast 5 to 10 rows of holes at one time, and the amount of ore and rock blasted can reach 300000 to 500000 tons. Millisecond blasting refers to the blasting method in which the medicine bags in adjacent holes are detonated in a very short time (calculated in ms) according to the pre-designed sequence. Advantages of multi-row millisecond blasting: (1) The blasting quantity at one time is large, the blasting times and the time for avoiding blasting are reduced, and the utilization rate of stope equipment is improved; (2) improving the crushing quality of ore and rock, and reducing the boulder rate by 40% -50% compared with single-row hole blasting; (3) The efficiency of perforating equipment is increased by about 10% ~ 15%, which is due to the increase of working time utilization coefficient and the decrease of the number of operations of perforating equipment and filling area after blasting; (4) Improve the efficiency of mining and transportation equipment by about 10% ~ 15%. Millisecond extrusion blasting with multiple rows of hol Multi-row hole millisecond extrusion blasting refers to the multi-row hole millisecond blasting in the case of residual blasting pile 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. Compared with multi-row millisecond blasting, multi-row millisecond extrusion blasting: The advantages are: (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 the mine using railway transportation, it is not necessary to dismantle the road before blasting, so as to improve the efficiency of mining, loading and transportation equipment. The disadvantages are: (1) High explosive consumption; (2) The working platform is required to be wider to accommodate the ballast pile; (3) The blasting pile height is large, which may affect the safety of excavator operation. In addition, no matter what kind of blasting method is used,dth rock bit, the Blasting Safety Regulations must be strictly implemented during blasting operations, safety warning signs must be set up, and warning work must be done to ensure the safety of personnel and property. 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