New mining project will create new jobs, and thus people will get an income, adding to the nations income.
Secondly, whatever the mine is mining will presumably have a value and be sold, wither domestically or overseas. It is not important wheter what is mined is gold, diamonds, salt or guano. If it can be sold, it will contribute to income.
Add Without Wings's material, and you might have yourself an essay. Cuz otherwise i cant see how you can write 2 pages for this question. Essay, my butt...