a few hints
at start, use all your 4 miners on teters mine and set on earth metals or bone. collect until your good to start selling. rocks are too cheap to sell.
certain 'mining' place needs different people.. miners wont always do the trick.
a way to mutate your rat for free is to use radiation. use it and keep it around 3. dont go over. it will cause toxins. if you overload your rat with it, it will cause toxins to rise very high and your creature's health go down fast.