Sulphate supergene minerals: An intuitive indicator for deep deposit in plateau regions.

The world‐class Rongna Cu(Au) deposit, located in the Duolong mining district, is the first epithermal‐porphyry deposit along the Bangong–Nujiang metallogenic belt. The acidic spring developed in the centre of the Rongna Deposit and its basin has a high amount of heavy metals. Therefore, metal elements (Cu, Pb, Zn, Cd, As, Cr and Hg), pH, SO42− of the Rongna River and the composition of its supergene minerals are studied to discuss the environmental influence and provide a theoretical basis for the comprehensive utilization and environmental management of the Rongna Deposit. The result shows that there are eight kinds of supergene minerals: natrojarosite, hexahydrite, tamarugite, anhydrite, pickeringite, bloedite, gypsum and naujakasite, among which, naujakasite is discovered for the first time in China. The material sources of these sulphate minerals and acidic water are from the sulphate in the ores that experience the leaching process and oxidation. The spring is severely acidified, whose pH values are 2.70–3.08, the single pollution index of Cr, Cd, Pb, Hg and As are less than 1, but the index of Cu and Zn exceed the Class III National Water Standard by about twice, showing a mild pollution, its comprehensive pollution index values 0.8 ~ (<2.5), showing good quality. The pH of Rongna River water values are 7.70–7.92, the single pollution index is less than 1, indicating no pollution, and the comprehensive pollution index is less than 0.8, indicating good quality. However, considering the vulnerable ecological environment in Tibet, the acidic spring still needs manual intervention. An open‐air reservoir can be built upstream of the acidic spring, and the pollutants can precipitate by natural evaporation and then be recycled. [ABSTRACT FROM AUTHOR]