Usually, when I spawn a big pack, first I do is to start running away to lose the slow ones if there are any.
When I lose the aggro on slow ones, I just turn and fight rest of them. After they take some damage , they dive down, so you can use that to move away from them ( They de-aggro by diving under).
Repeat until you have just one worm on you.
One boreworms should be easy pickings at that point. And if its a good Q node, just kill the rest of them

I use exclusively Uppercut/ Full circle combo. Mostly because Uppercut does not deal any damage on its own, so I can fight slimes without actually spliting them to often. I cannot one tap slimes on l9 like this, but at worst I get them to split only once, which is good.
Downside is that it's not to fast to clear packs like this, but yeah, you'll spawn a fucktone of slimmes /boreworms by just mining like this.
When mining, always try to have a straight way back, because if you are mining like an autist and pop boreworms, they will spawn around you in available tiles. Which means you are FUCKED.