I've been thinking about this a lot, whether it's more fun/interesting if the player has to figure out the unlock conditions, instead of the game just telling you everything. Both approaches have various pros and cons. Perhaps a prestige upgrade telling you the requirements is a good solution. Would have to rework the GUI though, since atm you can't even hover over the hidden/locked upgrades/buttons.
I kinda like the chaos of many runners depositing ores hehe, but I actually have plans regarding a late game upgrade that makes the maw suck/vacuum in nearby ore. Another option would be to simply make them throw ore further. I'll also be adding a few rituals that collect ore, as well as couple new retrieval units, so that should help a bit too.
Thanks for feedback!