Respuesta :
Answer:
Hard rock mining is a technique used to excavate hard minerals...
Explanation
Hard rock mining refers to various underground mining techniques used to excavate hard minerals, usually those containing metals such as ore containing gold, silver, iron, copper, zinc, nickel, tin and lead, but also involves using the same techniques for excavating ores of gems such as diamonds or rubies.
Hard rock mining requires removing ore from other substances such as quartz. Ores have different qualities and impurities depending on how they were formed. Often gold occurs as veins in quartz, which is mined as rocks from within a mine. This requires special machinery and often requires the skills of a geologist.