>>21710925shaft sinking setup for air vents or rises. You start by drilling an access bore down between the levels you want to connect, then this massive derrick is installed with rock bolts to hold it in place. Below, a set of cutter heads is installed and pulled upwards, cutting as it goes. Each bore gets bigger until the desired diameter is achieved. You can also just use one massive boring head to cut the hole but thats stupidly time consuming and if something breaks your hooped.
https://www.youtube.com/watch?v=0Vgi7rHNvXw 