EJAS-13599.pdf

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European Journal of Applied Sciences – Vol. 10, No. 6

Publication Date: December 25, 2022

DOI:10.14738/aivp.106.13599. Yin, J., He, D., Yin, Y., Shi, H., & Xiang, S. (2022). On Ore from the Dashuigou Tellurium Deposit, Tibet Plateau, Southwest China.

European Journal of Applied Sciences, 10(6). 458-472.

Services for Science and Education – United Kingdom

On Ore from the Dashuigou Tellurium Deposit, Tibet Plateau,

Southwest China

Jianzhao Yin

Wuhan Institute of Technology, Wuhan 430074, China

Jilin University, Changchun 130061, China

Dongsheng He

Xingfa School of Mining Engineering and School of Resources &

Safety Engineering, Wuhan Institute of Technology, Wuhan 430074, China

Yuhan Yin

Xuchang Electrical Vocational College, Xuchang 461000, China

Hongyun Shi

Orient Resources Ltd., Richmond, B.C., Canada V7E 1M8

Shoupu Xiang

Silvercorp Metals Inc., Suite 601-Building 1

China View Mansion, #A2 East GongTi Road, Chaoyang District

Beijing 100027, China

ABSTRACT

The Dashuigou independent tellurium deposit is the first and only tellurium deposit

discovered in the world so far. Studies have shown that tellurium will be the best

replacement for the next generation of green batteries. Therefore, a comprehensive

study of this unique deposit has both theoretical and practical significance. This

paper studies both the physical and chemical properties of the ore in the Dashuigou

independent tellurium deposit, and provides a theoretical basis for mining and ore

processing. The ore of the Dashuigou tellurium mine is composed of more than 30

kinds of minerals including carbonates, silicates, sulfides, oxides, tellurides, and

native element minerals. The ore contains Te between 0.01% and 34.58%. The ore

also contains beneficial elements such as Bi, Au, and Ag that can be comprehensively

utilized. The main types of ore are massive, veined, and disseminated.

Key words: ore; texture and structure; Dashuigou tellurium deposit; Tibet Plateau

INTRODUCTION

Tellurium (Te) is usually categorized as one of the scattered metals, semimetals, and/or

nonmetals that have similar geochemical characteristics with Clark values too low to enrich

into independent deposits, but that play very important roles across modern science, industry,

national defense, and the frontiers of technology. In the traditional theory of mineral deposits

and geochemistry, it is thought that Te cannot form independent deposits, but only exists as an

associated component in other metallic deposits. The abundance of Te in the Earth’s crust is

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Yin, J., He, D., Yin, Y., Shi, H., & Xiang, S. (2022). On Ore from the Dashuigou Tellurium Deposit, Tibet Plateau, Southwest China. European Journal

of Applied Sciences, 10(6). 458-472.

URL: http://dx.doi.org/10.14738/aivp.106.13599

very low. According to Li [1]

, the average content of Te in the Earth’s crust is only 2.0 × 10–8 in

China, and an even lower 1.34 × 10–9 worldwide.

At present, the world’s supply of refined tellurium is mainly recovered from Te-bearing

minerals including pyrite, sphalerite, chalcopyrite, galena, pyrrhotite, volcanogenetic sulfur,

bismuthinite, arsenopyrite, and cassiterite, etc. Generally, only sulfide ores containing more

than 0.002% Te can be used. As a result, the amount of refined tellurium that can be recovered

is very limited. Most of the recoverable Te in the world is from copper deposits, and it is

estimated that only 0.065 kg of Te can be produced in the refining process of one ton of copper

[2-3]

REGIONAL GEOLOGY

The Dashuigou tellurium deposit is located in the transitional belt between the Yangtze

platform and Songpan-Ganzi folded belt as part of the Tibetan Plateau, and nestled in the

convergence between the Indian, Eurasian, and Pacific Plates. The crust-mantle structures and

properties in the region are the result of tectogenesis throughout various geological periods.

Geophysical data indicate that the upper mantle below the region uplifts obviously. As a result,

the area has characteristics of high heat flow. There is also a low-velocity, low resistivity zone

in the middle crust that is interpreted as a decollement. In summary, this region is both very

active geologically and a very important south-north trending tectonomagmatic-mineral belt [3-

The strata, igneous rocks, and structures observed at the Dashuigou deposit trend south- northward. The strata are low-grade metamorphic rocks of the Silurian, Devonian, Permian

systems and middle-lower Triassic series. The well-developed igneous rocks in the region were

produced in different geological periods and include ultrabasic, basic, neutral, acidic, and

alkaline. Different types of mineral resources in the region are very rich; many of these are well

known, including Ti, V, Cu, Pb, Zn, SM, REE, coal, asbestos, and the Panzhihua vanadium titano- magnetite deposit [3-7]

MINE GEOLOLGY

The strata of the area are low-grade metamorphic rocks of the lower-middle Triassic age,

including marble, slate, and schist. The main wall-rocks of the ore bodies are schist and slate.

All the Triassic strata make up a NNE-trending dome. The geological and geochemical

characteristics in the area indicate that the protolith of the tellurium ore veins’ direct wall-rocks

is poorly differentiated, mantle-derived basalt [3-9]

Both faults and folds are well-developed in the area. The annular and linear structures together

make up special “Ø” pattern structures, which control the formation of different types of

endogenetic mineral deposits, including the Dashuigou tellurium deposit.

No intrusive rock emerges within a 5 km radius around the deposit. Only two small Permian

ultrabasic-basic rock bodies emerge within a 10 km range of the deposit. Large neutral, acidic,

and alkaline intrusive bodies exist beyond 10 km, which are unrelated to the deposit.

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European Journal of Applied Sciences (EJAS) Vol. 10, Issue 6, December-2022

Services for Science and Education – United Kingdom

Quantitative chemical analyses of Te, Bi, Se, As, Au, Ag, Cu, Pb, and Zn were conducted on

various rock samples including granites, metamorphic rocks, altered rocks, and carbonate veins

of different geological periods. The main findings are summarized below [3-11]

The Te content in the granites is under 1 × 10–7, which is similar to its Clark value in the Earth’s

crust. Te in the metamorphic rocks is slightly higher than in the granites and varies slightly

between metamorphic rocks of different geological periods, while being relatively higher in the

Triassic metamorphic rocks. Of the metamorphic rocks from the same geological period, the Te

content in the slate and schist is higher than in the marble. Te content in rocks of the same

stratohorizon of the same geological period also varies; namely, it is higher in rocks within the

mining area than in those beyond the mining area. Te content is closely related to the intensity

of alterations, whereby the ore-forming elements are not derived from the country rocks, but

instead from the mantle.

The deposit is located at the northeastern end of the Triassic metamorphic dome. The ore

bodies are controlled by and fill a group of shear fractures. Nine tellurium ore veins have been

discovered, which strike from 350 to 10 degrees and dip at 55 to 70 degrees westward. Widths

of the ore bodies vary between 25 and 30 cm. The narrow ore bodies are in the shape of

lenticular veins and have sharp contact with the wall rocks.

The altered rocks occur in narrow bands ranging between several centimeters to one meter in

thickness. Altered zones beside the massive ore veins are narrower, at only several centimeters

wide. The dominant alterations include dolomitization, silicification, biotitization,

muscovitizaion, tourmalinization, sericitizaion, greisenization, and chloritization.

Approximately thirty minerals are identified in the ore, which include tetradymite, pyrrhotite,

pyrite, dolomite, quartz, chalcopyrite, tsumoite (BiTe), tellurobismuthite (Bi2Te3), galena,

magnetite, gold, silver, electrum, ilmenite, calcite, calaverite, siderite, mannesite, rutile,

muscovite, biotite, sericite, hornblende, chlorite, plagioclase, K-feldspar, tourmaline, hematite,

garnet, apatite, and epidote. The first five minerals are the most important and comprise 85%

of the ore [3-13]

, though tetradymite is so rare that many monographs on mineralogy do not have

any related data on it [14-16]

Two mineralization epochs and five stages exist in the deposit: the Pyrrhotite epoch

(177.7~165.1 Ma): including three mineralization stages: carbonate stage (I) → pyrrhotite

stage (II) → chalcopyrite stage (III) (from early to late); and the Tellurium epoch (91.71~80.19

Ma): including two mineralization stages, namely: tetradymite stage (I) → tsumoite ±

tellurobismuthite stage (II) [3-4 & 17-18]

MINERAL COMPONENT

As mentioned above, there are more than 30 minerals in the ore according to mineral

identification and confirmed by electronic probe inspection. These minerals are mainly

carbonates, silicates, various sulfides and tellurides, and a small amount of oxides. These

minerals constitute different types of ores in different proportions, forms, occurrences,

textures, and structures. They are briefly described as follows:

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Yin, J., He, D., Yin, Y., Shi, H., & Xiang, S. (2022). On Ore from the Dashuigou Tellurium Deposit, Tibet Plateau, Southwest China. European Journal

of Applied Sciences, 10(6). 458-472.

URL: http://dx.doi.org/10.14738/aivp.106.13599

Carbonate

The carbonate minerals in the mining area are extremely developed, and are produced in large

quantities in both pyrrhotite and telluride veins. The carbonate minerals formed in the early

stage mostly appear in the form of coarse-grained veins. The carbonate minerals are also

important carriers of telluride minerals.

The carbonate minerals in the mining area are mainly dolomite, calcite, and siderite (Tables 1,

2 and Figure 1). Compared to the respective theoretical values of the chemical compositions of

these three minerals (Table 2), the dolomite in this mining area is poor in magnesium and rich

in iron but cannot reach the level of iron dolomite, so it can instead be called iron-bearing

dolomite.

Table 1. Electron probe analysis results of carbonate minerals from the mine (wt.%)

Figure 1. Siderite veinlets are interspersed in the fissures of the calcite veins (thin section (-)

×200)

C a M g F e M n S r B a C O 3

II-1 1 3 0.3 5 13.12 9.3 4 0.8 8 0.0 0 0.0 0 4 4.51 9 8.2 0 1.0 7 1.0 7 0.2 6 0.2 6 0.0 0 0.0 0 2.0 0

2 3 1.9 0 13.3 8 7.6 8 0.9 1 0.0 0 0.0 0 4 4.9 1 9 8.78 1.11 1.11 0.2 1 0.2 1 0.0 0 0.0 0 2.0 0

3 2 9.51 10.50 13.4 7 1.75 0.0 0 0.0 0 4 3.9 6 9 9.19 1.0 5 1.0 5 0.3 8 0.3 8 0.0 0 0.0 0 2.0 0

4 3 1.4 3 15.0 2 7.16 0.0 0 0.0 0 0.0 0 4 5.4 5 9 9.0 6 1.0 9 1.0 9 0.19 0.19 0.0 0 0.0 0 2.0 0

5 2 8.54 12.9 6 11.4 1 1.0 4 0.0 0 0.0 0 4 4.18 9 8.13 1.0 1 1.0 1 0.3 2 0.3 2 0.0 0 0.0 0 2.0 0

6 3 3.2 5 15.6 5 4.3 4 0.76 0.0 0 0.0 0 4 6.3 1 10 0.3 1 1.13 1.13 0.11 0.11 0.0 0 0.0 0 2.0 0

7 0.3 7 2 0.6 7 3 3.4 1 0.4 2 0.0 0 0.0 0 4 3.59 9 8.4 6 0.0 1 0.0 1 0.9 4 0.9 4 0.0 0 0.0 0 2.0 0

8 0.3 7 2 4.0 9 3 0.0 7 0.4 2 0.0 0 0.0 0 4 5.2 8 10 0.2 3 0.0 1 0.0 1 0.8 1 0.8 1 0.0 0 0.0 0 2.0 0

9 3 0.0 7 16.2 2 6.17 0.57 0.0 0 0.0 0 4 5.4 4 9 8.4 7 1.0 4 1.0 4 0.17 0.17 0.0 0 0.0 0 2.0 0

10 3 0.58 13.4 9 9.4 2 0.57 0.0 0 0.0 0 4 4.8 5 9 8.9 1 1.0 7 1.0 7 0.2 6 0.2 6 0.0 0 0.0 0 2.0 0

11 2 9.4 3 14.3 1 10.54 0.4 1 0.0 0 0.0 0 4 5.4 3 10 0.12 1.0 2 1.0 2 0.2 8 0.2 8 0.0 0 0.0 0 2.0 0

12 3.3 7 1.8 7 54.2 3 0.0 4 0.0 0 0.0 0 3 7.9 3 9 7.4 4 0.14 0.14 1.75 1.75 0.0 0 0.0 0 2.0 0

I-4 13 3 0.13 16.11 6.10 0.57 0.0 0 0.0 0 4 5.3 3 9 8.2 4 1.0 4 1.0 4 0.16 0.16 0.0 0 0.0 0 2.0 0

14 50.3 4 1.2 2 2.8 5 0.6 0 0.0 0 0.0 0 4 3.3 4 9 8.3 5 1.8 4 1.8 4 0.0 8 0.0 8 0.0 0 0.0 0 2.0 0

15 2 9.0 5 15.3 6 9.0 3 0.6 8 0.0 0 0.0 0 4 5.52 9 9.6 4 1.0 0 1.0 0 0.2 4 0.2 4 0.0 0 0.0 0 2.0 0

16 2 9.11 14.8 7 8.6 2 0.77 0.0 0 0.0 0 4 4.8 4 9 8.2 1 1.0 2 1.0 2 0.2 4 0.2 4 0.0 0 0.0 0 2.0 0

17 3 0.17 16.0 9 6.4 9 1.0 2 0.0 0 0.0 0 4 5.8 5 9 9.6 2 1.0 3 1.0 3 0.17 0.17 0.0 0 0.0 0 2.0 0

18 53.6 1 1.0 9 0.3 1 0.0 0 0.0 0 0.0 0 4 3.4 5 9 8.4 6 1.9 4 1.9 4 0.0 1 0.0 1 0.0 0 0.0 0 2.0 0

19 54.4 1 1.0 8 0.0 0 0.0 0 0.0 0 0.0 0 4 3.8 8 9 9.3 7 1.9 5 1.9 5 0.0 0 0.0 0 0.0 0 0.0 0 2.0 0

2 0 54.6 4 0.0 0 0.8 0 0.0 0 0.0 0 0.0 0 4 3.3 7 9 8.8 1 1.9 8 1.9 8 0.0 2 0.0 2 0.0 0 0.0 0 2.0 0

2 1 56.2 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 4 4.10 10 0.3 0 2.0 0 2.0 0 0.0 0 0.0 0 0.0 0 0.0 0 2.0 0

2 2 54.75 0.2 6 0.12 0.0 9 0.0 0 0.0 0 4 3.3 8 9 8.6 0 1.9 8 1.9 8 0.0 0 0.0 0 0.0 0 0.0 0 2.0 0

2 3 54.4 7 0.9 2 0.0 0 0.0 9 0.0 0 0.0 0 4 3.8 1 9 9.2 9 1.9 5 1.9 5 0.0 0 0.0 0 0.0 0 0.0 0 2.0 0

D1 2 4 55.0 0 0.3 2 0.0 8 0.0 1 0.0 0 0.0 0 4 3.57 9 8.9 8 1.9 8 1.9 8 0.0 0 0.0 0 0.0 0 0.0 0 2.0 0

I-8

S rO B aO C O 2 total at o mic numb er FeO M nO

II-2

s amp le # t es t p o int C aO MgO

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European Journal of Applied Sciences (EJAS) Vol. 10, Issue 6, December-2022

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Table 2. Theoretical values of chemical compositions of some carbonate minerals19

The calcite in the mining area is generally rich in magnesium with some being rich in iron, and

can be called magnesium-bearing calcite and iron-bearing calcite respectively.

The magnesite in the mining area also clearly exhibits iron-rich chemical characteristics, while

the siderite is slightly iron-poor but calcium-rich. Test points 7 and 8 in Tables 1 and 2 are

actually the isomorphic substitution series between MgCO3 and FeCO3.

On the frequency diagram of CaO, MgO, and FeO content (Figure 2), most carbonate samples

from the study area are concentrated in the dolomite and calcite range, with little siderite and

no magnesite. Figures 3 and 4 reflect the same results.

C aO MgO FeO C O 2

II-1 1

4 (Ca, Mg, Fe)(CO3)2

12 (Fe1.75, Ca, Mn)(CO3)2 siderite 62.01 37.99

I-4 13 (Ca, Mg, Fe, Mn)(CO3)2 dolomite 30.41 21.86 47.73

14 (Ca1.84, Fe, Mg, Mn)(CO3)2 Fe-Mg calcite 56.03 43.97

18 (Ca1.94, Mg, Fe)(CO3)2

19 (Ca1.95, Mg)(CO3)2

20 (Ca1.98, Fe)(CO3)2 Fe calcite

21 (CaCO3 calcite

22 (Ca1.98, Mg)(CO3)2

23 (Ca1.95, Mg)(CO3)2

D1 24 (Ca1.98, Mg)(CO3)2

(Mg, Fe, Ca, Mn)(CO3)2

(Ca, Mg, Fe, Mn)(CO3)2

56.03 43.97

30.41 21.86 47.73

dolomite 30.41 21.86 47.73

dolomite

Mg calcite

I-8

o xid e theo ret ic al value 1 9

II-2

30.41 21.86 47.73

s amp le # t es t p o int c hemic a l f o rmula minera l

dolomite

Fe-rich magnesite 47.81 52.19

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Yin, J., He, D., Yin, Y., Shi, H., & Xiang, S. (2022). On Ore from the Dashuigou Tellurium Deposit, Tibet Plateau, Southwest China. European Journal

of Applied Sciences, 10(6). 458-472.

URL: http://dx.doi.org/10.14738/aivp.106.13599

Figure 5. Lead grey-silvery colored tetradymite ± tsumoite (BiTe) ± tellurobismuthite (Bi2Te3)

fine veinlets in massive pyrrhotite (dark colored background) + dolomite (brownish white)

from the deposit (sample #: SD40, Ore body #I-1 in Drift 3)

Figure 6. The Kα X ray image indicating chemical composition distributions of telluride

including tetradymite and tsumoite (white): the denser the white spots, the higher the Te

content, the black colored is pyrrhotite from the deposit (×540)