Construction technology of bedrock in vertical shaft wellbore - drilling blasting
Drilling blasting work accounts for about 20% to 30% of the total cycle time. Most of the boreholes are pneumatic rock drills , such as the YT-23 light rock drill , and the YGZ-70 rail heavy duty rock drill. The latter needs to be drilled with an umbrella-shaped drill stand, and the depth of the eye is generally 3~5m. The blasting work includes the selection of blasting equipment , the determination of blasting parameters and the preparation of blasting charts. (1) Blasting equipment In the construction of vertical shafts, water-resistant explosives are required. Commonly used water-resistant explosives are water-resistant rock ammonium nitrate explosives, water-gel explosives and nitrifying sweeteners. Water gel explosives are widely used. Detonation equipment usually uses domestic second detonator, millisecond delay detonator and detonating cord. When there is danger of explosion of methane and coal dust explosion wellbore or wellbore through the coal seam, the coal mine safety must be no more than an extension of explosives and electric detonators millisecond delay of 130ms. The power of the shooting gun is mostly AC power supply or special detonator. When using AC power, the voltage should not exceed 380V. (2) Blasting parameters Including the depth of the blasthole, the number of blastholes, the consumption of explosives, and so on. When using artificial hand-held drills, it is suitable for 1.5~2.0m; when using umbrella drills, it is suitable for 3.0~5.0m. (3) Blasting chart The blasting chart includes: blasting raw conditions, blasting parameters, blasthole layout and expected blasting effects. Nitrile Exam Gloves Formers apply to produce nitrile gloves. Glove Mold,Nitrile Exam Gloves Former Mold,Nitrile Glove Former ,Nitrile Glove Former Mold ZIBO HAOXIANG CERAMICS TECHNOLOGY CO.,LTD. , https://www.haoxiangceramics.com