The Qilian Mountains that separate Qinghai and Gansu provinces have been identified as an important ecological safety shelter for the country's vast western region, runoff formation area of the Yellow River's source, and a high priority area for biodiversity protection.

Such unique ecological significance prompted the central authorities to establish the Gansu Qilian Mountains National Nature Reserve way back in 1988. Yet that didn't prevent the Qilian Mountains from reckless human exploitation, thanks to the area's rich mineral reserves.

Since 2015, the Ministry of Environmental Protection has found itself in a tough fight against rampant illegal mining that has been damaging the biosphere, polluting the environment, and impairing the already fragile ecology, which can have grave consequences on the source of the Yellow River. Following a request for rectification the ministry issued to Gansu provincial authorities, a 2016 survey found that the problem "remains serious", leading to three vice-governor-level Gansu officials being disciplined last year for "inaction".

That accountability storm prompted both the central and local authorities to vow that the issue would be thoroughly investigated, heralding the largest-scale ecological protection campaign for the Qilian Mountains in Gansu.

Perhaps we overestimated the efficacy of the periodical environmental protection campaigns. And, more important, we neglected the fact that the Qilian Mountains sit on the border of two provinces, and those pledges applied only to Gansu. In fact, a major company in neighboring Qinghai has engaged in large-scale, "predatory" mining for over a decade on the other side of the Qilian Mountains, raking in about $2 billion in illicit profits.

Those large, open-pit coal mines, in existence for more than 10 years, couldn't have remained invisible to local authorities. Or did they turn a blind eye to them? Especially considering the blanket screening ordered in the wake of Gansu's investigation, and the fact that such sophisticated equipment as drones are widely available to local government agencies charged with surveillance missions.

Several prefecture-level officials have been dismissed after the scandal became public. More are subject to disciplinary actions as the authorities in Qinghai have promised to leave no stone unturned. But the focus has been on dereliction of duty, the reason why officials downplayed the nature of problems involved.

Local police and disciplinary and supervision commissions have set up a special task force to thoroughly investigate the issue and bring the unscrupulous mining barons and the rest of those responsible for the environmental damage to book.

Given the astronomical profits at stake, no probe should be called thorough until they take potential corruption into account. Let's hope this time, the thorough investigation not only helps to bring the guilty to justice, but also leads to the restoration of nature on the Qilian Mountains.