Article reprinted from "China Science News"
A sample of spodumene with a predominantly white and slightly greenish color courtesy of the interviewee
Lithium ore, known as "white oil", is an extremely rare white light metal resource. At present, 75% of the mainland's lithium resources rely on imports. With the development of the global new energy industry, the demand for lithium resources has increased sharply.
A few days ago, the reporter learned from the Institute of Geology and Geophysics of the Chinese Academy of Sciences (hereinafter referred to as the Institute of Geology and Geosciences of the Chinese Academy of Sciences) that the scientific investigation and research team of the Institute of The Tibetan Plateau discovered super-large lithium ore in the Qiongjiagang area of the Himalayas.
The lithium mine is considered to be "expected to become the third largest lithium mine in mainland China after Bailongshan and Chuanxi Methyl card in southern Xinjiang" and is "the first pegmatite lithium mine with industrial value in the Himalayas". The results were published in the Journal of Petrology.
On some issues of qiongjiagang super-large lithium mine, China Science News exclusively interviewed Qin Kezhang, head of the scientific research team and director of the Key Laboratory of Mineral Resources Research of the Chinese Academy of Sciences.
How did scientists find super-large lithium mines?
"We discovered this mine under the guidance of scientific theories that broke through traditional cognition." Qin Kezhang said.
He said that the reason why the lithium mine has not been discovered before is mainly because the traditional view is that the formation of large areas of pale granite in the Himalayas is due to the remelting of sedimentary rocks and in situ intrusion, which is usually not used as a target for prospecting.
"The large-scale Cenozoic pale granites exposed in the Himalayan orogenic belt, which stretches more than 2,500 kilometers from east to west on the southern edge of the Qinghai-Tibet Plateau, have long been recognized by the first Qinghai-Tibet scientific expedition, but have never been used as a prospect for rare metals for more than 40 years." Qin Kezhang told China Science Daily.
After more than ten years of investigation and research, the research team of Academician Wu Fuyuan of the Institute of Geology and Earth sciences of the Chinese Academy of Sciences created the theory of high heterogeneous genesis of pale granite in 2015, and systematically proposed that the Himalayan pale granite is a highly crystalline and differentiated granite and a deep invasive body in different places, which means that the pale granite in this area has good rare metal mineralization potential. The theory breaks with conventional wisdom.
"Based on academician Wu Fuyuan's new theory, we began to look for rare metal ores in the Himalayan pale granite belt." Qin Kezhang said.
Subsequently, a number of units investigated the regional rock mass and found that more than 20 rock masses contained rare metal mineralization, and the metal combination was mainly beryllium-niobium-tantalum (tin-tungsten) combination, of which the tin-tungsten-beryllium deposit in The cuonadong was evaluated to a large scale. Although spodumene minerals have been found in a handful of 4 pegmatites, no lithium ore bodies of industrial value have been found.
In view of the current situation of beryllium-rich and poor lithium in the Himalayas, in 2020, Qin Kezhang proposed a scientific prediction of "finding lithium to the farther and higher ends of strongly differentiated granites" on the basis of comparing and summarizing the symbiotic separation laws of lithium and beryllium ore symbium in the rare metal mineralization belt of the mainland Altai and East Qinling Mountains, preferring the prospect area for key inspection, and found lithium ore in the summer of 2021.
Where are the super large lithium mines?
Qiongjiagang lithium mine landform. Courtesy of respondents
"We found this lithium mine 3,000 meters south and west of the Poor Family Gang Peak in the Himalayas." Qin Kezhang said that out of the idea of giving good wishes, researchers named the lithium mine "Qiongjiagang Lithium Mine" according to the harmonic sound of "Poor Family Gang".
Qin Kezhang introduced that they found more than 40 spodumene pegmatite belts with a width of 10 meters to nearly 100 meters, which formed 4 rock vein groups and 4 mineral belts.
"The surface outcrops of the Qiongjiagang lithium mine are very good, so we can clearly see the length, width and surface outcrop drop. The length of the four belts is more than 1000 meters, of which 2 are about 100 meters wide, and are concentrated in high altitude areas from 5390 meters to 5581 meters. Qin Kezhang said.
How "big" is a super-large lithium mine?
Pegmatite lithium ore body with researchers as the "reference". Courtesy of respondents
Generally speaking, the "large" lithium mine contains more than 100,000 tons of lithium oxide resources, so how "large" is the Qiongjiagang lithium mine known as "super large"?
Qin Kezhang told China Science Daily that the lithium oxide resources in the ore body can reach 1.0125 million tons, "this value is calculated based on conservative estimates of the volume of the ore body and the content of lithium oxide resources."
"The reason why we say 'conservative' is because when we estimate the volume of lithium ore, the length is only taken 2/3 of the actual length, the width is only taken 1/2 of the actual width, and the thickness is only taken 1/2 of the inferred depth, that is, the total volume is only taken 1/6." Qin Kezhang said.
In terms of lithium oxide content, Qin Kezhang introduced that the scientific research team selected a total of 59 representative samples, selected areas with large volume, representative structure and more uniform mineral distribution for cutting and crushing, and the weight of a single fragment was not less than 1 kg, and then they mixed each powder sample thoroughly and evenly, and finally sampled according to the amount of samples required for the test.
The results of the analysis showed that the average lithium oxide content was 1.30%. "The whole rock trace elements were tested separately in the Aoshi Mineral Laboratory and Wuhan Shangpu Analysis Technology Co., Ltd., and retested in the laboratory of the Institute of Geology and Earth science of the Chinese Academy of Sciences, and the relative error of trace elements measurement was less than 10%." Qin Kezhang added.
Is there a dispute?
The series of articles on the discovery of the Qiongjiagang lithium mine was published in the journal Journal of Petrology, an academic journal of Chinese, in November 2021.
"Before the publication of the paper, some peers questioned the scale of the Qiongjiagang lithium mine after hearing about it, because such a large-scale pegmatite rare metal deposit is only a handful at home and abroad." Qin Kezhang said.
Qin Kezhang said that after the publication of the paper, the above doubts were largely eliminated, but the controversy since then began to focus on "why only 1/6 of the ore volume is estimated" when estimating the volume of the ore body.
"A lot of people ask me after perusing the article, 'Why is the discount so big', 'Why don't you take 1/3, 1/2', I said, 'Take 1/3 is actually OK, but taking 1/2 is a bit too optimistic'." Qin Kezhang said.
He said that the reason why only 1/6 of the ore volume was estimated was because they thought that they should be more cautious in the early stage. "The situation inside the ore body is now invisible, it doesn't matter if it is a little less at the beginning, if you find better grade and larger scale later, of course, it is better."
In addition, the reporter learned that the Journal of Petrology is supervised by the Chinese Academy of Sciences, sponsored by the Chinese Society of Mineralogy, Petrology and Geochemistry and the Institute of Geology and Geoscience of the Chinese Academy of Sciences, and is included in the Science Citation Index (SCI), with a compound impact factor of 3.316 in 2021.
For the paper published this time, the journal anonymous review believes that "this is a huge breakthrough in the prospecting and exploration of rare metals in the Himalayas" and "not only has important scientific value for understanding the mineralization of rare metals in pale granite, but also has outstanding practical significance for prospecting and exploration".
What is the industrial value?
The newly discovered lithium mine was evaluated by the scientific research team as "the first pegmatite lithium mine with industrial value in the Himalayas". So, what is its industrial value?
Qin Kezhang said that it is generally believed that when the lithium oxide resource content exceeds 0.8%, lithium ore has the industrial value of mining, and of the 59 samples they collected, 44 samples have an industrial grade of lithium oxide resource content (more than 0.8%), and the highest sample has a lithium oxide resource content of 3.3%.
In addition, he told reporters that in addition to lithium oxide, there are about 39,800 tons of beryllium resources in the ore body, reaching a large scale; about 2358 tons of tantalum oxide resources, which have also reached a large scale; about 7074 tons of niobium oxide resources, which are small scale. Moreover, more than 90% of the mineral composition in the Qiongjiagang ore body is quartz, potassium feldspar and sodium feldspar, as well as some mica, which are used to manufacture glass, ceramics and insulating materials in the Cocoto Sea Mine in Xinjiang, and the main rock ore in the area is expected to be effectively utilized, generating corresponding economic benefits and greatly reducing waste emissions.
Are there any mining conditions?
In the paper, the scientific research team proposed that "the Himalayan Belt is expected to become the most important reserve base for rare metal mineral resources in China". So, does the Qiongjiagang lithium mine have the conditions for mining?
"Qiongjiagang Lithium Mine has good mining conditions." Qin Kezhang responded, "Spodumene particles are coarse, about 10 cm to 20 cm, which belongs to the ore dressing; the location of the mining area is conveniently located, and it has been connected to the rural cement road; it is in positive terrain, which is conducive to mining; the ore body is exposed, no need to dig deep; and it is far away from the core nature reserve of Mount Everest." ”
However, he said that at present, the lithium ore is still in the initial "pre-investigation" stage, but it is basically determined the distribution range of the ore body and the types and contents of useful elements. From the discovery to the mining of a mine, it is generally necessary to go through four stages of pre-inspection, census, detailed investigation and exploration, of which pre-inspection is to determine the location and general situation of the mine, the census is to eliminate the uncertainty of the pre-inspection stage through engineering means, the detailed investigation is to explore the availability of the deposit, and the exploration is to determine the specific mining plan.
For the next step, Qin Kezhang said that the researchers will also enrich and improve the theoretical system and prospecting mark of rare metals in highly differentiated granite, further carry out scientific investigation and research on the area where the lithium mine is located and look for new lithium-containing pegmatites to determine whether the Qiongjiagang lithium mine and its surroundings can form a larger complete lithium ore belt, so as to make greater contributions to the construction of the mainland Himalayas into a new strategic replacement base for lithium beryllium rare metal resources.
Related paper information:
https://doi.org/10.18654/1000-0569/2021.11.02
https://doi.org/10.18654/1000-0569/2021.11.06
China Science News (2022-02-15 1st Edition Highlights)
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