As the first light of dawn breaks, frost crystals float over the meadows of Jiangcang No.1 Well in the Muli Mining Area of Qinghai Province, and a herd of yaks leisurely graze by the lakeside.

Tashi, a herder, rubs his hands together to warm them, stroking the grass shoots, and reflects: "A few years ago, this place was covered with mining pits, like an open wound. Now, the grass has grown as tall as the yaks' legs, and even the marmots have returned to settle down."

This 4,200-meter-high land bears witness to the ecological miracle created by the engineers of China Coal Science & Technology Group’s subsidiary, Zhongmei Eco-environmental Technology Co., Ltd. (referred to as Ke Gong Ecological), who used technology and craftsmanship to restore the land.

The Muli Mining Area is the largest coal mining area in Qinghai Province, consisting of four districts, including the Jiuquhe and Jiangcang districts. Due to years of intensive mining and illegal coal extraction, the high-altitude grassland wetlands in the Muli Mining Area have suffered significant damage. The scars left by open-pit mining stretch for miles, with dark mining pits filled with water, forming glaring "black lakes." The rupture of the permafrost layer has caused surface subsidence, breaking up surrounding meadows. The area's vegetation coverage dropped sharply from 80% to less than 15%.

"This is not just simple environmental damage; it represents a crack in the ecological barrier of the Qinghai-Tibet Plateau," said Han Keming, the project manager for the Jiangcang No.1 Well slag hill integrated management project in the Muli Mining Area.

In 2020, the Qinghai Provincial Party Committee and Government fully halted coal mining in the Muli Mining Area and began comprehensive ecological restoration. Among these, the Jiangcang District, with higher mining intensity, became a key area for restoration.

To address this, China Coal Science & Technology Group immediately formed an expert team, led by Wang Shuangming, an academician of the Chinese Academy of Engineering, to conduct field research and surveys in Jiangcang District. The team members overcame severe plateau reactions, mapping the site during the day, and delving into ecological problems caused by coal mining, such as grassland degradation, permafrost degradation, river diversion, and slope instability. At night, they discussed ecological restoration plans in tents while bundled in military coats.

After persistent efforts, on September 2, 2020, the comprehensive restoration plan proposed by Ke Gong Ecological, which included "slag hill slope reduction, mining pit backfill with a gentle slope (for plateau lakes), rock wall restoration, micro-topography reshaping, soil reconstruction, and vegetation restoration," received high recognition from Qinghai's natural resources department. The Qinghai Muli Mining Area Jiangcang No.1 Well slag hill integrated restoration project officially entered the substantive implementation phase.

In the early stages of the project, protecting the unmined underground mine passages at the bottom of Jiangcang No.1 Well became the most challenging problem.

"Conventional backfilling might crush the mine structure and destroy future mining conditions. Restoration must not only address the present but also leave room for future development," said Han Keming.

"We innovatively adopted the 'zoned construction—bi-directional backfilling—gentle slope covering' technique, scientifically determining the backfill height, optimizing the slag stone cleaning pattern, reducing slope weight, and completing the backfill, thus reshaping the topography and laying the foundation for future soil reconstruction and improvement," said Yin Lei, the on-site manager for the Jiangcang No.1 Well slag hill integrated restoration project.

Greening the High-altitude, Cold Plateau Mining Area

Since 2021, the project has faced its most difficult task—restoration of vegetation. In the high-altitude cold plateau areas, mining area grass planting and greening projects are a first in China, and there was no mature technical support available. How to improve the soil? What grass species to plant? What is the survival rate? Everything had to be "trial and error."

The approach adopted by Yin Lei was to maximize the exposure of in-situ soil, make the most of the stripped soil, and align as much as possible with nature, setting the tone for efficient greening at Jiangcang No.1 Well.

"We proposed three types of soil matrix improvement methods for cold mining areas, utilizing local sheep dung resources to form an efficient soil improvement plan: 'mature sheep dung base expansion—commercial organic fertilizer optimization.' We also selected six plant species suitable for local growth, such as short awned alkali grass, and optimized the mix. The construction process included 'matrix layer planting, drainage ditch construction, slag soil improvement, organic fertilizer and grass seed broadcasting, raking and compacting, nonwoven fabric coverage, and removal of secondary stones,' which significantly improved grass seed survival rates," said Yin Lei.

Due to the unpredictable climate in the Jiangcang No.1 Well mining area and a lack of meteorological data support, Han Keming and Yin Lei set up a small weather station and installed soil moisture and temperature monitoring systems to collect meteorological and soil data. This data supports later greening management, replanting, and long-term climate monitoring.

After years of relentless effort by Ke Gong Ecological, Jiangcang No.1 Well has undergone a dramatic transformation. A 1,900-acre ecological restoration area has formed a stable vegetation community with an average of 14,000 plants per square meter and 89% coverage, creating a near-natural, low-maintenance, and sustainable high-altitude mining area landscape.

"Today, the ecological system of Jiangcang No.1 Well has significantly improved its self-restoration capacity and stability, effectively reducing geological hazards such as landslides, river blockages, and permafrost thawing," said Yin Lei.

While ecological benefits continue to emerge, the economic benefits of the Jiangcang No.1 Well mining area have also grown significantly. Thanks to the improved ecological environment, the area's livestock and tourism industries are booming, bringing in over 7 million yuan in direct economic benefits annually and saving more than 4 million yuan in ecological restoration costs.

The Jiangcang No.1 Well slag hill integrated restoration project, undertaken by Ke Gong Ecological, was selected as a typical case of multi-party collaborative governance for national mine ecological restoration in 2024 and won the "Classic Engineering" Award for Construction Quality in the Coal Industry.