China's mineral sector shifting to green exploration

A heavy-lift helicopter swung over a mountain clearing in Guangyuan, Sichuan province, a cable dangling from its belly. Below, workers grabbed the hook, clipped it to a bundle of drilling equipment wrapped in heavy-duty straps, and watched it rise toward a ridgetop where no road had ever reached.

Over the course of a day in September 2023, the helicopter ferried 26 metric tons of rigs and supplies for seven boreholes across three drill platforms in Wangcang county, where steep canyon walls and dense forest had made road construction impossible.

The operation is part of a growing shift toward low-disturbance, green exploration in China's mineral sector, where geological teams are trading high-impact methods for alternatives to reconcile mineral exploration with environmental protection.

"The bill came to around 1.4 million yuan ($209,000), but that number alone misreads the job," said Hu Dong, general manager of a mining company at the seventh geological brigade of the Sichuan provincial geological bureau, who was responsible for the project.

Hu said that if a road had been cut into the mountain, it would have meant months of negotiating compensation with villagers for their farmland, filing forestry permits and rerouting around ecological red lines.

"No slope was cut, no tree fell, and no worker hauled steel up a 60-degree face by hand. When you consider the saved safety risk, the avoided vegetation loss, and the shortened schedule together, the lift was cheap," he added.

The airlift was not the end of the environmental chain. The project used biodegradable drilling mud in a closed-loop circulation system, sealed waste oil and drill cuttings for off-site disposal, and restored all platforms with native vegetation after the geological report was filed.

The experience also pointed the way forward. In subsequent projects, the team has continued with helicopter transport and added heavy-duty drones for lighter loads, which are cheaper to operate and equally capable of bypassing roads.

Two thousand kilometers north, Liu Xiangxu, a senior engineer at the Heilongjiang provincial institute of geological sciences, was solving a different problem — how to see what lies beneath weathered rock without scarring the forest that blankets the mountains.

Traditional mineral exploration in the Greater and Lesser Hinggan Mountains relied on mechanical trenching, which involved digging channels sometimes hundreds of meters long and 10 meters wide to expose the bedrock beneath. "From satellite images, traditional trenching looks like scars on the mountains — wounds that take decades to heal," Liu added.

Recognizing the ecological value of these ranges — home to vast swaths of old-growth taiga, or coniferous forest, and the headwaters of the Heilong and Songhua rivers — the region, which is also a nationally designated key metallogenic belt rich in lead, zinc, silver and molybdenum, tightened environmental approvals around 2014.

To replace the trench, Liu's team developed a small-angle steel-cable coring system — a portable full-hydraulic rig drilling at zero to 45 degrees, pushing a core barrel down with a steel strand instead of a gravity-fed rope and pulling it back the same way.

The method solved two industry headaches at once — near-surface rock is fractured and unstable, and at angles below 30 degrees, traditional rope tools simply fail.

"We started by hand, about 10 people pulling the steel cable on a shift," Liu recalled of the first field test in September 2015. "It took two months of trial and error before we automated it."

The numbers tell the story. A 100-meter trench consumes 1,000 to 1,500 square meters of forest and takes a decade to heal, while a small-angle drill pad occupies just 16 sq m, leaving behind only a 10-centimeter-diameter borehole after the work is done. Core recovery rates exceed 92 percent, and mineral deposits identified through the method are more than three times those found by traditional trenching.

Since 2019, the Heilongjiang institute has completed over 50,000 meters of small-angle drilling across more than 50 projects, sparing over 600,000 sq m of forest and saving over 50 million yuan in forestry compensation, according to Liu.

The technique has obtained invention patents in China, the United States, Russia, Canada and Australia, and has been applied in places such as the Inner Mongolia and Xinjiang autonomous regions, as well as Liaoning and Jilin provinces.

These field-level innovations reflect the country's institutional push. China's Ministry of Natural Resources requires all fiscal-funded exploration projects to include green exploration measures in their plans, list environmental fees as separate budget items, and prioritize remote sensing, geophysics and drilling in place of trenching in forested and wetland areas.

Shandong province published the country's first comprehensive provincial-level standard for green exploration in 2021, covering 11 core areas from survey design to site restoration. In the Qihe-Yucheng area of western Shandong, exploration teams followed the standard to protect farmland — drilling fluid circulates through fiberglass pipes rather than open pits, and the top 30 cm of arable soil is stripped in layers, stored, then returned in the same order afterward. During the 14th Five-Year Plan period (2021-25), the zone added 142 million tons of rich iron ore reserves with every hectare of temporary exploration land reclaimed and returned to farming.

A national industry standard for green exploration was issued in 2021 by the ministry, and green exploration specifications for solid mineral resources were released last month. Together they embed green requirements at every stage of the project life cycle, and non-compliant projects are ordered to halt operations.

Both Hu and Liu see the same trajectory — from compliance to instinct.

"When I started working in 2010, people had very little environmental awareness. But now the concept has taken root in the heart of every geological team member," Liu said.

"We must protect our land — its forests, grasslands, black soil and farmland — as carefully as we protect our own eyes," he added.

limenghan@chinadaily.com.cn