(7) Zhongtiaoshan is full of copper mines.

There are almost copper mines in every mountainous area in Shanxi, but those that form deposits and have mining value are limited to Zhongtiao Mountain. Zhongtiaoshan copper mine is widely distributed, with a long history and considerable output. Shanxi's copper reserves are the fifth in China, and Zhongtiaoshan is the third largest copper base in China (the first in Yunnan and the second in Liaoning). Zhongtiaoshan copper deposit occurs in five strata from Neoarchean to Paleoproterozoic. Bizigou and Tongkuangyu in Yuanqu have formed two large industrial deposits. Small copper mines are scattered all over the place, concentrated at the junction of Wenxi, Jiangxian and Yuanqu counties, becoming the famous "copper triangle".

Exploration on the trend of copper vein in mine

Copper is the largest non-ferrous metal in China, and its domestic output can't meet the rapidly developing industrial demand. Therefore, the industrial grade of copper mine is very low. As long as the content of metallic copper in the ore reaches 3 kg per ton, it can be included in the scope of the deposit, and 5 kg can be extracted per ton, which is an industrial recoverable requirement.

The average recoverable grade of Zhongtiaoshan Copper Mine is between 0.5%- 1%, but due to its large reserves, it has formed an annual production capacity of10 million tons of ore. What's more gratifying is that deposits like Tongkuangyu are accompanied by useful metal elements such as molybdenum, cobalt and gold, which can be recovered as important by-products and improve the comprehensive utilization value of copper mines. Before local energy smelting in 1990s, ores were transported to Shenyang for refining through Liyuan-Tongkuangyu special railway line, and dozens of kilograms of gold were returned to Yuanqu every year.

There are copper mines everywhere in Zhao Zhong, which means that green malachite, an oxidized mineral of copper, can often be found in rocks working in the field. However, in order to form industrial deposits, besides the lowest industrial grade, a certain amount of reserves is needed, and this second condition is difficult to meet. In Zhongtiaoshan area, an exploration team of metallurgical department and a survey team of geological department have been looking for reserve bases for mines, but the speed of prospecting can't keep up with the speed of mining, so the shortage of mine resources has not been alleviated.

Zhongtiaoshan copper mine has a long history. According to legend, during the Warring States period, there were 30 copper casting furnaces in Jiangzhou, which was one third of the national copper smelting furnaces in that year. There is no direct archaeological basis for where the copper in the Central Plains came from, but the copper of so many bronzes in the Bronze Age in the Central Plains did not always come from distant Central Asia (the birthplace of the earliest bronzes in the world), did it? In the Central Plains, that is, today's Henan, Shanxi, Hebei and Shaanxi, only Zhongtiaoshan can provide rich copper resources. Chalcopyrite, the main mineral of copper mine, has the shiny metallic luster like metallic copper and the golden yellow color of copper, so it is easy to be found and even cast (actually melted) like metallic copper. Although Zhongtiaoshan Mountain has been mined for thousands of years, most of the rich mines have been lit by the ancients, but many places, such as Hu Ping and Luojiahe, Tongshan Town, Yuanqu, still have rich mines. During the mining process of Bizigou and Tongkuangyu, ancient mining remains were also seen. Therefore, Zhongtiaoshan copper mine is the main copper-producing area in the Bronze Age in the Central Plains.