Superlarge lead-zinc deposit, mined since 1996.

The large lead–zinc deposit of Qiandongshan–Dongtangzi can be divided into two sections: the Qiandongshan ore section and the Dongtangzi ore section. A total of five lead–zinc bodies have been delineated in the large lead–zinc deposit of Qiandongshan–Dongtangzi, of which No. I-1 and No. II-1 ore bodies are the main ore bodies (Figure 5). The two main ore bodies currently have an estimated resource of approximately 2 million tons of lead and zinc. The ore bodies mainly occur near the Si/Ca interface in the contact zone of the biocrystalline limestone of Gudaoling Formation and the carbonaceous calcareous phyllite of Xinghongpu Formation.
The No. I-1 ore body is located on both wings and the saddle of the northern secondary fold of the “M” complex anticline, and is strictly controlled by the northern secondary fold. The total length of ore body control exceeded 1700 m (402 m in the Dongtangzi ore section and 1304 m in the Qiandongshan ore section), with thicknesses ranging from 0.91 m to 9.36 m, and an average thickness of 8.14 m. The Pb grade varies from 0.17% to 3.93%, with an average of 1.21%, while the Zn grade ranges from 0.27% to 7.61%, with an average of 5.68%. The ore body is stratified and stratiform-like in shape, consistent with the common occurrences of the medium-low temperature hydrothermal lead–zinc deposit.
The No. II-1 ore body is located on both wings and the saddle of the southern secondary fold of the “M” complex anticline and is strictly controlled by the southern secondary fold. The total length of ore body control is 2300 m (1400 m in the Dongtangzi ore section and 900 m in the Qiandongshan ore section), with a thickness ranging from 0.48 to 40.29 m and maximum thickness in the saddle portion. The average thickness is 12.23 m. The Pb grade ranges from 0.21% to 4.60%, with an average of 1.44%, while the Zn grade ranges from 0.21% to 11.88%, with an average of 5.51%.
The deposit exhibits zonation of Pb, Zn-Zn, and Pb-Au from east to west on the plane of the deposit. The Pb-Zn grade decreases from east to west along the trend of the ore body and correlates closely with the variation in thickness of the ore body.
the paragenetic association can be divided into two periods, namely the sedimentary period and the hydrothermal mineralization period. The hydrothermal mineralization period can be further divided into three stages: Stage I, a polymetallic sulfide–ankerite–quartz stage; Stage II, a quartz–pyrite-rich sulfide–ankerite stage; and stage III, a quartz–carbonate–sulfide stage.

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References