加拿大道姆矿在掘进天井时使用喷射喷嘴降尘,其天井倾角为 50°斜长一般不超过60米,天井断面1．5×1．5米,天井内设有人行间和废石间,凿岩是在木板台上进行,板台距工作面2．1米;每个工作面有二名凿岩工,每人使用一台75毫米的上向凿岩机;用0．8-3米长的钢钎,十字形碳化钨钎头。喷射嘴包括内外两个管,内管通以压气,当压气从喷嘴 Canada Dumm. When using the jet nozzle to dredge the tunnel, the pit inclination is 50 °. The inclined length is generally no more than 60 meters and the cross section of the pit is 1.5 × 1.5 meters. The patio is equipped with interplayer and waste rock, The rock is carried on a wooden pallet with a pallet of 2.1 m above the face; two rock drills on each face, each using a 75 mm uphole rock drill; a 0.8-3 m long steel Brazing, cruciform tungsten carbide drill head. The jet nozzle includes two tubes inside and outside, the inner tube through to pressure, when the pressure from the nozzle