>To compensate, they mine essential minerals and other things from the ground. Using these pure minerals, they make a pure cocktail of sustenance which they take swigs from every so often. Sort of like a multivitamin for everything.

It's interesting to consider the effect of early technology on the course of evolution. Humans seem to have made one of our great leaps forward when we figured out how to cook food, meaning we could partially digest it outside of the body, so we could feed those growing brains.

If some alien found a way to feed on inorganic material (which would turn it from a consumer to a producer in its food web, incidentally) it might affect the course of their evolution if it happened early on; if it happened later it would alter their global environment since their cities would be fed with inorganic material and produce organic waste. This would presumably find its way into the environment and alter the energy budget of the local ecosystems, unless they found a way to recycle it.