nooo! contractors just burn $, be conservative, in house air leg miner bores 1.8 - 2 m round in a development round,,, takes say 2hrs, charge up say 30mins,,, if !!! vent is ok 30mins to clear smoke,,, 2hrs to bog,,, an easy day your looking at 2m advance,,, have seen 3.8m advance per 8hrs ,,,,, jus get ya shit together!!!!!
