YE Qin-fu¹, SU Hang², ZHANG Deng-min¹

(1. Hualian Zinc & Indium Co. Ltd, Maguan 663701, China;
2. Yunnan Hualian Mineral Resource Exploration Co.Ltd., Qujing 655000, China)

Abstract: The Dulong super-large Sn-Zn polymetallic deposit in Maguan County, Yunnan Province is one out of three cassiterite sulfide deposits in the southeastern Yunnan, China. The Tongjie-Manjiazhai ore block is the uppermost one of the deposit. With the expansion of mining and developing scales for years, geological resources of the Dulong mine are gradually consumed, so it is an urgent task for the mine to explore new alternative mineral resources. The researches show that there are widely distributed large amounts of ‘low-grade ore resource’ in the Tongjie-Manjiazhai ore block with important exploiting value. Based on the summary of the geological exploration and production data of the Tongjie-Manjiazhai ore block, it is found that the spatial distribution of “low grade ore resource” is consistent with those of Sn-Zn polymetallic industrial orebodies. Especially, carbonate rocks with schist of the 2nd and 3rd members of the Lower Cambrian Xinzhaiyan Formation are the most favorable host strata for the low grade ore resource, which occurred dominantly around the main industrial orebodies, in fault zone of detachment between marble and schist, and shattered fault zone. The mineral components and metal mineral distribution characteristics of the low-grade ore resource are similar to those of the industrial ore, only its proportion of ore minerals is lower than that of the industrial ore. The low-grade ore resource can be classified as the major skarn type sulfide ore, minor marble type and schist type sulfide ore. Furthermore, the positive relationships of two elements out of Sn, Zn and Cu in the low grade ore resources indicate that there are close paragenetic relationship among valuable elements of Sn, Zn and Cu. In addition, there is obvious zonation of ore-forming elements in the plane of the deposit, as the Zn grades of ores are decreased, but the Cu and Zn grades of ores are increased gradually from west to east, whereas the association of ore-forming elements is changed from Cu+Zn (northern) to Zn (central) to Sn+Zn (southern) from north to south in the plane of the deposit. This research has provided new evidences for the mining, mineral separation and recycling of the low grade ore resources of the Dulong mine.

Keywords: Low-grade ore resource, ore type, quality characteristics, distribution rule, Tongjie-Manjiazhai ore block, Dulong Sn-Zn polymetallic deposit.

ACTA MINERALOGICA SINICA Vol.41, No.6, 2021, page 635-642