Which would be Sunsoft Level 9 on the Genesis. This is what I have so far roughly. 1 Climber, 3 Builders, 10 Bashers and 2 Miners.
(http://img.photobucket.com/albums/v240/dm-48/750e4d42.jpg)
And then I go on to do this.
(http://img.photobucket.com/albums/v240/dm-48/1db4899f.jpg)
I bash through the things at the top and build from the pit on the left to release the rest of the Lemmings. (Why I wasted a basher on the left where I build to release the Lemmings I don't know, the Lemmings can walk over that) This would all work if they could make it over the bit where I've mined to the left through the pillar but they can't. Also, with this "solution" I have 2 Bashers left over, 3 if you don't count the one I wasted. The one way wall leads me to believe it's part of the solution, but I can't see how.
So in other words, I need help. =P
Try mining the lemming a little earlier. Then your solution 'should' work. I find excecution of that level complete hell, thanks to the lack of a replay feature.
The mining is more lateral than the beam, the beam descends pretty quickly so surely the earlier I mine, the higher I will come through on the other side? =/
This picture should help:
(http://www.geocities.com/guestlevels/lemmings/coalmine.png)
The red line is where you mined. Mining at the green line will just barely make the step traversible. So to be safe, you should start mining left at a position behind the green line.
D'oh! Now why didn't I think of that? >_< It's so blatantly obvious now you've pointed it out, I don't know why I didn't think to try that.
Thanks. ^^