The value of the tailings Such as guangxi nandan tin polymetallic has 61 tailings, in total 25.22 million tons of tailings, contains a lot of non-ferrous metal tin, antimony, lead, zinc, silver, gold, indium, cadmium and arsenic, sulfur and other non-metallic mineral, grade is above the national industrial grade indexes, some already achieved large or…

Natural sand mining limit, make artificial gravel rapid development in society. Industry rapid development, the machinery industry is the rapid development of the s, was already gone. Artificial stone production investment, not just the need to consume huge Labour force, and the efficiency is not high also, the result is that took a lot of…