During my studies at the university, I've visited some industries in the field of metallurgy through student programs often.
One of the most fascinating of them was a visit to the Sarcheshmeh copper mine and factory as the biggest copper producer in my country in the Kerman province. This mine contains in average 0.65% copper in the form of Chalcopyrite which is mined about 240kt ore annually through the open-pit cycle method. According to the ore grade, it was loaded and hauled to stockpiles, heaps, or waste rock storage piles, which I've written about in this post.
Another one was visits of lead and zinc industries that are raised close to the unique Angouran mine in the Zanjan province. This mine has 16 million tonnes of ore with a zinc concentration of 26% and a lead concentration of 6% and consists of both oxide and sulfide ore. In the case of zinc constituent, the oxide concentrate is produced for manufacturing the zinc bar through the hydrometallurgical route, that this part is going to deplete. However, the majority of sulfide concentrate is exported due to lack of investment and technology. Here, there is more information about this visit.
Likewise, the lead oxide concentrate of Angouran mine is used to produce the metal through the pyrometallurgical route, but the sulfide part is exported. Read more.