我队在單机單掌作业中,曾經广泛的应用了二次掏槽爆破,取得了显著的良好效果,特別是在工作面少的情况下,保証了平均台班效率1.74公尺的記录。实际証明采用这种方法能比一次掏槽深孔爆破获得較高的爆破率,并且基本上避免了发生,“放筒”、“挤死”現象。我們是在一晝夜兩次循环的条件下組织二次掏槽爆破的,同时,由于坑道不甚深,通风条件比較好,因此对爆破工作也是一个有利因素。每台班除原有的工种以外,再适当的配备1—2名运搬工人搗掌。在作业力法上:由岩工首先將8个規格眼及第一次掏槽眼打完。規格眼的深度按着进尺要求和根据凿岩时間一般为1.8～2.2公尺,第一次采用錐形掏槽,眼数为3～5个,眼深为1.2～1.4公尺(如图1);第一次凿岩工作結束后,进行第一次 In our single-unit single-clan operation, our team has extensively applied the secondary undercutting blasting and achieved remarkable good results, especially in the case of a small working face, which ensured the record of the average working efficiency of 1.74 meters . It has been proved that this method can get a higher blasting rate than the one cut deep-hole blasting, and basically avoid the phenomenon of “discharge tube” and “squeeze-out”. We organize the second undercut blasting under the condition of two circulations day and night. At the same time, because the tunnel is not deep and the ventilation condition is good, it is also a favorable factor for the blasting work. In addition to each class in addition to the original type of work, and then properly equipped with 1-2 transport workers pounded on the palm. In the force method: the rock will be the first of eight eye and the first tipped eye finish. The specifications of the depth of the eye according to the requirements of the footage and according to rock drilling time is generally 1.8 to 2.2 meters, the first use of taper cut, the number of eyes 3 to 5, the depth of 1.2 to 1.4 meters (Figure 1); After the first drilling work, the first time