The cutting work with the sub-column sublevel caving method is mainly based on the bottoming of the roadway, the compensation space is explored, and the leakage work is carried out. [Reference content] The range of the bottoming should be determined according to the shape of the ore body, the scope of the ore and the area under the mine. When the ore is stable, the bottoming range should generally exceed 0.5 to 1.0 m of the falling boundary to ensure good blasting effect. (1) The concept of compensation space The compensation space is when the ore falls from the ore body, its volume is larger than the original volume, so before the blasting, a certain amount of space must be excavated to accommodate the enlarged volume. We call this space a compensation space. That is, the compensation space is used to compensate for the swell of the falling mine. (2) Method of forming compensation space For this typical scheme, there are two methods for forming the compensation space depending on the stability of the ore. 1 When the ore is stable, it can be formed by the shallow hole method and the medium-deep hole method. 2 If the ore is not stable, the compensation space can be formed by cutting several lanes. 1) When the ore is stable 1 shallow hole method to explore compensation space That is, at the level of pulling the bottom, tunnel one or several lanes. (2 × 2 m 2 ) and cut one or several cross lanes at appropriate positions as the blasting free surface. In these bottoming lanes, use shallow holes to open the state, gradually form the bottom space, and then top up to a certain height. Form the required compensation space. Advantages: Not limited by rock drilling equipment. Disadvantages: low work efficiency, high labor intensity, increased processes, and increased difficulty in production management. Therefore, there are many used. 2 medium deep hole (deep hole) method to explore compensation space This method is to dig the flat road and the cross road at the level of the bottom, to use the flat road as the free surface, to drill the middle or deep hole in the cross road as the free surface, and to drill the middle depth in the roadway. hole. In the ore-mining method, these medium-deep holes are pre-blasted, and after cleaning, a compensation space is formed. When the ore is not stable, when the cross-shaped bottoming roadway can not meet the necessary compensation space, the following two methods can be used: 1 increase the number of bottoming roadways; 2 use the square bar pillar method to mine 1~2 layers, and mine When blasting, attach explosives to the pillars and blow them up (some mines use this method). The blasthole: W=1.2~1.5 meters, three blastholes are arranged in each row, and the free-face blasting is performed by using the bottom crossing. Each row blasts 3 to 5 rows of holes to form a bottoming space. On the basis of the bottoming space, several rows of horizontal holes are blasted according to the size of the compensation space to form a sufficient compensation space. 2) When the ore is not stable Since the ore is not stable, it is not allowed to form a large horizontal compensation space before falling. Therefore, the space of the cross roadway is often used as a compensation space. That is, drilling at the bottom level (ie, the upper part of the funnel neck): grouping of alleys and cross-spans, and drilling deep holes in the pillars between the alleys and the cross-spans. These medium-deep holes and the deep holes of the falling mine are blasted in advance. Thereby a cushion layer and a compensation space are formed. (The bottom roadway specification is generally 2 × 2 m 2 ) The advantages of using the medium-deep hole method to excavate the compensation space are: high efficiency, safe operation and simple process. Therefore, it is an effective method of pulling down when the rock drilling equipment allows. Ethylene Glycol Tertiary Butyl Ether Etb Price,Cas7580 85 0,Ethylene Glycol Tertiary Butyl Ether,Ethylene Glycol Tertiary Butyl Ether Price ShanDong DeXiang International Trade Co.,Ltd , https://www.dexiangchemical.com