1-Move an explorer to under the right of the left Metal hook, Build 2 ladders. Build a 3rd ladder at the left edge of the top step.
2-Block at the right of the top step, foot on edge, move another explorer to Build at the right edge of the 2nd ladder top.
3-Turning around, build at the 2nd topmost step, Build left, Mine, Bash, Mine, Dig at the column left, Build to turn around, and left.
4-Bash the group out. Last lemming must Dig after being turned right, two scoops, Build.
5-Blocker must use inmediate Build. Build to turn around down shaft.