On a wide field in Wuchengdaren village in Laizhou, Shandong province, a 30-meter drilling tower rises against the flat farmland horizon. In about six months, this rig will have pierced nearly 3 kilometers into the Earth, retrieving rock cores that could verify the presence of gold deposits.

The project, launched on Wednesday by the Shandong Provincial Bureau of Geology and Mineral Resources, is part of a broader campaign comprising 36 exploration projects with a total investment of 76 million yuan ($11 million). The goal is to add 20 to 50 metric tons of gold reserves in the Jiaodong area within a single year.

Jiaodong, a peninsula along the southern coast of the Bohai Sea in eastern Shandong, already holds a quarter of China's proven gold reserves, making it the world's third-largest gold district.

However, after intensive mining for decades, even centuries in some places, easily accessible surface and shallow deposits have long been exhausted in the region.

Therefore, efforts in recent years have been redirected toward deeper explorations into the Earth.

In the past, drilling depths were mostly below 2,000 meters. Nowadays, the bureau has mastered the core technology of ultra-deep, ultra-inclined and ultra-difficult small-diameter drilling.

The bureau now undertakes 83 percent of the nation's scientific drilling projects that are above 3,000 meters. It even set a new record of full core extraction at a depth of 2,843.17 meters in global marine scientific drilling.

In 2023, the No 6 geological team uncovered a large gold deposit in Xilaokou village, Rushan of Weihai, with nearly 50 tons of gold metal identified, making it the largest gold deposit in the Weihai area to date and marking a significant breakthrough in deep mineral exploration in the northeastern margin of the Jiaolai Basin.

Contrary to traditional methods, modern gold prospecting no longer involves wandering onto a field and digging at random. The process begins months before the first drill bit turns.

"We conduct geological research with physical detection methods such as electrical and magnetic surveys, along with chemical analysis, to identify subsurface anomaly zones," said Ma Xiaopeng, deputy director of the exploration engineering division with the No 6 geological team of the provincial bureau.

"Once we pinpoint the target areas, drilling helps us further narrow down the scope," he said.

Once cores are extracted, field geologists will analyze the samples in laboratories. "After receiving assay results, we comprehensively analyze the ore body's occurrence conditions, grade and depth," Ma added.

With technological innovation, the bureau has continuously opened new frontiers.

In Laizhou Bay, the bureau has adopted 2D reflection seismic technology — typically used on land — for marine exploration of the gold-bearing fault zone in recent years.

"We are building digital models that integrate geological, geophysical, geochemical, and drilling data with artificial intelligence," said Zhang Chengwei, Party secretary and director of the provincial bureau. "We are shifting gold prospecting from an experience-driven to an intelligence-driven model."

At the end of 2025, 10 departments in Shandong jointly issued the implementation plan for high quality development of gold industry (2025-2027), focusing on promoting deep exploration in the Jiaodong region.

The push comes as China continues to lead the world in both gold production and consumption. Last year, demand for gold bars and coins surpassed that for gold jewelry for the first time, a structural shift in the market. Industrial demand, particularly from electronics and new energy sectors, is also rising steadily.

"Ensuring national resource and energy security is the primary responsibility of the geological and mineral system," Zhang said.

zhaoruixue@chinadaily.com.cn