You need to keep mining until you get enough to get runestones. The progress is exponential and rewards longer runs. The collapse mechanic should be locked out until there are actually runestones to be gained from using it.
There is a pretty common event that gives you a runestone time to time and those don't count towards the runestone cost, so you can use that option pretty early if lucky and actively playing.
Yea, I wasn't able to get those everytime they came up early on. But a tooltip and lock out so you can't collapse without getting any runestones would be good.
I'ts always available so some people can restart an early run and use a different approach without having to reset the whole game. But I take that into account and I'm adding a better warning if you don't have any runestones when colapsing.
