For most metals as well as cement, China produces about 45% of total world production plus - minus a few percentage.
I don't understand their copper production, they purchase copper concentrate from Chile for a pretty high price, and then in case of sulfide copper they generate SO2 (sulphur dioxie) that either is emitted ad pollutant or used to produce sulphuric acid.
I doubt it is too much money in it for them, interesting?