Mine

Mines are your first way of producing Metal, and are pretty expensive to build.

Main use
They are used to produce Metal. You need to build at least one mine at the start of ANY match, since 2 mines are never enough to make you win.

You'll need Metal Store in order to store the metal produced by your mines, unless you spend the metal fast enough, so you don't have floating ressources.

Other info
Mines can be upgraded into upgraded mines (yeah...). Those produce more metal (6 instead of 4) but also consume a bit more energy (10 instead of 5).

Knowing a mine needs 30 seconds to be built and it costs 300 metal, you'll need to wait a whole 105 seconds after placing a mine for it to pay for itself.

Upgrading a mine takes 22 seconds, which means it doesn't produce for 22 seconds, so you lose 88 metal, it costs 75 metal, meaning it'll pay for itself 103.5 seconds after starting the upgrade process.

There exists a Rush called "eco rush", that consists in building and upgrading most mines the fastest possible, giving you a total of 35 metal/second, which is pretty tremendous. The issue with such a rush is that you have no weapons before your enemy gets heavy weapons out.