Need asap some minerals are widespread throughout earth’s crust, but occur in such low that miming is not economically practical

Some minerals are widespread throughout Earth’s crust, but occur in such low quantities that miming is not economically practical. Examples are Cerium, Copper, Cryolite ore that is mined for the production of Aluminium, are all present in low quantities on the Earth's crust. The extraction of Gold and Platinum from deep within the Earth's crust is also very difficult and the economics is very complicated.