Six people were killed after inhaling poisonous gas while trying to illegally dig gold in an abandoned mine in the northern Shanxi province, domestic media reported Monday.

The deaths were attributed to inhalation of highly fatal hydrogen cyanide gas released during the chemical process used to extract gold from low-grade ores, domestic media reported, citing local police. Law enforcement officials found the miners — all from the neighboring Henan province — lifeless some 2,700 meters inside a cave in Jiangxian County after they were reported missing.

Commonly known as “cave wash,” the practice of using sodium cyanide solution to dissolve gold ores, and which emits hydrogen cyanide during the reaction, is widely used in illegal gold mining in China. Over the past year, rising gold and coal prices have led to an influx of illegal mining, as people try to cash in from the trend, according to media reports.

The risky practice has led to several poisoning-related deaths, including seven in the central Henan province earlier this year. Police in the eastern Shandong province — home to some of the country’s largest gold mines — also arrested nine people for partaking in illegal activities this year.

Meanwhile, in Shanxi, officials last week vowed to crack down on illegal mining after more than 20 people were trapped and two killed in a flooded coal mine earlier this month. Multiple government officials, including the mayor of Xiaoyi City, where the mine was located, were removed from office after the Dec. 15 incident.

Following the flooded mine incident, the central government has ordered all relevant departments in coal-producing provinces to strengthen supervision against illegal mining, which had largely disappeared before being “resurrected” amid increasing coal demand.

Editor: Bibek Bhandari.

(Header image: People Visual)