Chinese engineers have revealed plans to drill a 10-kilometre-deep borehole into the Earth’s crust in an attempt to further our understanding of the planet’s inner workings.
Drilling began in late May in the Tarim Basin and will penetrate rock formations from a time when dinosaurs ruled the world.
Scientists are hopeful the megaproject will reveal rich mineral and rare earth deposits, but also say the work can help assess geological risks in the area.
Construction on what will be the country’s deepest borehole began at the end of May and represents another landmark in China’s exploration of areas beneath the Earth’s outer layer, as per a report from a state media outlet, Xinhua News.
Last week, China completed a behemoth 12 000-tonne offshore drilling platform in the Bozhang gas field. Once operational, the seven-and-a-half-story tall rig will produce a steady supply of clean and reliable energy for the Beijing-Hebei-Tianjin tri-city cluster.
The Tarim Basin is in the southern half of China’s north-western Xinjiang province. The region is sparsely populated – much of the Basin’s territories lie within the Taklamakan Desert, the Tibetan Plateau and the Tian Shan mountain range, marking its borders in the south and north.
Drilling ten kilometres below the surface brings about some unique challenges, with the geology in the region is not conducive to easy drilling.
The Tarim Basin is dry, rocky and ancient. It began forming between Carboniferous and Permian periods and ended sometime during the early Triassic Period, roughly 250-200 million years ago.
As a result, there are successive layers of strata, or sedimentary rock formations, from the Paleozoic, Mesozoic and Cenozoic periods up to 15 kilometres thick.
Sun Jinsheng, a China Academy of Sciences researcher, compared the difficulty of the task to driving a truck on a pair of thin steel cables.
Despite its impressive depth, China’s new borehole falls shy of the Russian Kola Superdeep Borehole in Siberia which, at a little over 12 kilometres, is the deepest artificial hole ever created. The Soviet-era borehole took 20 years to drill, reaching the 12-kilometre milestone in 1989.
Work at the site was forced to halt when temperatures inside the borehole reached dangerous highs. According to a BBC report, the mercury reached 180 degrees Celsius at certain times – more than double what engineers had estimated.
Another area of concern when drilling superdeep boreholes is the cost, according to International Continental Scientific Drilling Programme representative, Uli Harms. Harms said drilling megaprojects require an ever-increasing investment, much of it dedicated towards operational costs.
In fact, in the 1960s, the US’s attempt at a superdeep borehole, Project Manhole, reached a depth of 183 metres before being abandoned due to rising costs.