I'm currently playing Iron Will, and am at the point where I need tons of coal. Normally, the Deep Mining upgrade adds a coal per tick for each miner you have, however, since I don't have any kittens, I don't have any miners.

Does this upgrade have a hidden extra effect in Iron Will mode, like, say, meteors made of coal? Or is this upgrade completely useless if you don't have any miners?

1 Answer 1


Yes. I decided that the best way to find out was to try it out. The "Deep Mining" upgrade gives a 0.01 coal/sec production rate to your mines. And this isn't just Iron Will mode. A quick glance at the game code finds this in the code that defines the effects for the Mines:

if (game.workshop.get("deepMining").researched){
            //fun but ugly hack
            self.effects["coalPerTickBase"] = 0.003;
            //coal.value += self.effects["coalPerTick"] * self.val;

It doesn't check for Iron Will mode anywhere here. Therefore, you can get coal without any miners at all if you have this upgrade.

  • 2
    Deep Mining doesn't affect your miners at all. It only affects the Mines themselves. It's only Geologists that produce coal as a job. Commented Nov 6, 2014 at 14:11

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