... Factory prices groove tools/notching tools/drilling toold/rock drill/cutting tools/hydraulic splitterA new powerful and extremely cost-effective alternative ... prove: after notchinghole, it can get good effect with hydraulic splitter, static expand powder or explosive blasting, the distance ... 1.5-2 times, thus reduce drilling and powder cost.Drill first, then notch, notching time is only 0.1 ...