Types of underground mining

Hard rock mines, the type always shown in old cowboy movies where there are long passages held up with wooden beams are used in the mining of:

* Minerals such as gold, lead, uranium and silver * Halite (rock salt) * Coal * Opals * Diamonds Open pit mines are used to extract materials like coal and are essentially hust large holes that grow bigger as more material is removed. Open pit mines also describe some types of oil sands operations.

Solution mines use liquid to remove minerals from undergroud strata by pumpimg down a solvent (water) and pumping up asolution of the water and the sesired mineral (salt, sulfur, potash)