China is killing the race for critical minerals with the largest antenna on Earth

Hidden within the granite wilderness of central China lies an antenna so vast it dwarfs New York City five times over – a 500-kilowatt electromagnetic leviathan originally built to whisper to submarines. Now, it is broadcasting China’s dominance in the global scramble for critical minerals. As nations race to secure lithium, cobalt and rare earths for green tech supremacy, Chinese geologists are deploying this monster – and its cousins – to detect ore and energy resources buried kilometres deep. In recent years, researchers have reported a large number of game-changing finds including the world’s largest gold deposit, ultra-large lithium reserves and never-before-seen deep uranium ores. Their world-leading electromagnetic arsenal, systematically revealed for the first time in a China Geological Survey (CGS) study published in the peer-reviewed journal Geophysical & Geochemical Exploration in August, leaves competitors in the dust. Every ultra-high-power system exceeding 100kW operates in China, while the most potent American tool manages a mere 30kW. “The development of these systems marks China’s world-leading position on electromagnetic exploration theory and technology,” wrote the team of authors led by senior engineer Chen Hui with the CGS Development and Research Centre in Beijing. For decades, mineral exploration has relied on traditional methods like direct current resistivity and induced polarisation. And as surface-level deposits have been exhausted, the search has moved deeper into what geologists now call the “second mineral space”, between 500 and 2,000 metres (1,640 and 6,560 feet) underground. Geologists believe that most mineral resources on our planet have remained untapped because the continental crust can be as thick as 70km (43 miles), and human mining activities at present have barely scratched the surface. At these depths, signals from ore bodies are faint, masked by cultural noise from power lines, urban infrastructure and mining operations. China has responded by redefining the scale of electromagnetic exploration. By dramatically increasing transmitter power to over 100kW, Chinese scientists are amplifying the signals sent into the Earth, effectively drowning out interference and penetrating deeper than ever before. But greater power can reduce precision. Traditional electromagnetic (EM) surveys have often relied on two-dimensional measurements, making it difficult to accurately model complex underground structures. Now, China is deploying distributed sensor arrays and multidirectional field sources to conduct true three-dimensional imaging. In Tibet’s Jiama copper mine, a high-power tensor CSAMT (controlled-source audio-magnetotellurics) survey achieved unprecedented resolution at depths of over 3,000 metres, according to Chen and his colleagues. The data, when compared with core samples, revealed a clear “low-high-low” resistivity pattern consistent with known ore zones – a result that outperformed even natural-source magnetotellurics, which struggle in noisy environments. The most striking example of this technological ambition is the wireless electromagnetic method (WEM) project – a 500kW, continent-scale transmitter system with two massive antenna lines, one 80km and another 120km long, laid out in near-perpendicular directions across central China. Designed initially for naval communication, it has become a game changer for mineral exploration. In a nationwide test in 2023, signals from the WEM system were successfully detected from Tibet to Inner Mongolia to Guangdong – distances exceeding 2,000km. At the Xiong’an New Area, researchers recorded a magnetic field signal of up to 2,444 femtotesla during transmission – seven times stronger than the natural background noise at targeted frequencies. Thanks to these powerful systems, Chinese scientists have developed new methods like the wide field electromagnetic method. Pioneered by renowned geophysicist Professor He Jishan, this method is unlike conventional techniques that require measurements far from the source. Instead, it uses advanced mathematical models to extract reliable data even in the “near-field” zone, greatly increasing efficiency and depth. Meanwhile, time-frequency electromagnetic systems are being used to extract not just resistivity but also polarisation and permeability. These parameters are crucial for distinguishing between different types of ore bodies. With control over the technology and data, China is positioning itself to lead in the next phase of resource discovery with ultra-high-powerful systems up and running as Western companies rely heavily on low-powered EM equipment, according to Chen’s team. “Except for Russia, Western land-based electromagnetic exploration rarely uses ultra-high-power electromagnetic instruments, and the most powerful instruments they produce are also custom-designed at China’s request,” they added.

China is killing the race for critical minerals with the largest antenna on Earth

.css-1c6uqr6{color:inherit;font-weight:inherit;font-size:inherit;font-family:inherit;line-height:inherit;overflow-wrap:break-word;}Chinese-built high-powered device is five times bigger than New York City and leads the global search for lithium, cobalt and rare earths

Chinese-built high-powered device is five times bigger than New York City and leads the global search for lithium, cobalt and rare earths