Qinghai province has initiated a three－year plan to repair the environment in the Qilian Mountains, where a serious case of illegal mining was reported.

Last month, media reported that the local Xingqing company had been excessively mining a coal field in Muli town since 2006. More than 25 million metric tons of coal had been mined by the company under the guise of ecological restoration, creating around 15 billion yuan ($2.19 billion) of profit.

Standing on the border of Gansu and Qinghai provinces, the Qilian Mountains were designated a nature reserve in 1988. Neighboring the mountains, the Muli coal mine is Qinghai's only site with rich coal resources.

On Monday, the Qinghai provincial government announced the action plan, which will be implemented over the next three years in Muli and the neighboring regions suffering from environmental destruction.

The plan requires local departments to shut down all mines in the region and draft repair plans for each mine by the end of the year. Between 2021 and 2023, a comprehensive program should be conducted to further improve the local environment.

Regions included in the plan will become a high plateau ecological park with mine sites restored by 2023.

As of midnight on Monday, 485 pieces of construction equipment and 965 workers had arrived at the Muli coal mine, Xinhua News Agency reported.

In the past two decades, many illegal mining projects and hydropower stations have sprung up as a result of lax supervision in the Qilian Mountains, inflicting significant damage on the environment.

Since 2017, the central government has initiated two rounds of high－profile inspections related to the environment－including one in the mountains－which has been plagued by decades of logging, mining, the building of factories and tourism.

After the illegal mining in Muli was reported in August, a special inspection team lead by the province's vice－governor was sent to Muli. The Haixi prefecture government, where the mine is located, also sent a special team to investigate.

On Aug 9, two top officials of Haixi prefecture were removed from their posts for dereliction of supervision duty on illicit mining. Another three officials from local supervision departments in Haixi have also been removed from office and put under investigation.

Moreover, some other officials from the prefecture's government, the Qaidam Circular Economy Pilot Zone that oversees the mountains, the natural resource department and the ecology and environment department are also being investigated.