long hole meaning in English

长洞
长距离球穴
深炮眼

Exploding technology about long hole blasting in rock roadway
岩巷中深孔爆破技术
Drilling technology of long hole using for discharging gas from coal seams
抽放瓦斯顺煤层长钻孔施工技术
Gas drainage from underground mine with 1000m branched long holes along seam
煤矿井下顺煤层千米枝状长钻孔抽采瓦斯技术
Preliminary application of gas pre - drainage from coal seam by long holes in heading face to prevent coal and gas outburst
掘进工作面应用长钻孔预抽煤层瓦斯防止煤与瓦斯突出的效果
Prospect of application of foam pump increasing pressure equipment in construction of drilling long hole for sucking and exhaling mash gas
泡沫增压技术在煤矿瓦斯抽放长钻孔施工中的应用前景