Right now, once you get a miner Mk2, your resource extraction rate is doubled. If you put 2 slugs in and push it to 200%, those bonuses fully multiply giving you 4 times the productivity on the ore vein you are mining. Mk2 miners already make impure ore bodies undesirable on their own. Past a certain point, it's obvious that pure ore is the only thing you would want to be mining. It makes vast areas of the map just worthless. Very few games use multiplicative multipliers this way for similar reasons. Theses bonuses need to be reigned in so that they don't just scale out of control.
The standard way to do things is that multipliers only multiply the base. In other words, if I have 2x and 2x, the base amount of 1x should only be counted once giving a final result of 3x.
