The Chinese corporation China Railway Construction Corporation has developed a unique drilling machine “Gante Jiliang” (translated as “Steel Ridge”). This is the world’s first tunneling shield capable of drill vertical shafts more than 1000 meters deep in hard rock. The device, weighing 500 tons and with a diameter of 8.1 meters, has already begun work at an iron ore project in the northeast of the country.
China’s surface deposits are being depleted, and huge mineral reserves are hidden in the depths. According to the Geological Survey of China, antimony resources at a depth of up to 2 km are 5.3 times greater than known reserves. For lead, zinc and gold, this ratio is about four, for tungsten, lithium, rare earth metals and coal – about three to one. But getting to them using traditional methods is difficult and dangerous.
The main engineering problem of vertical drilling is the removal of crushed rock. Unlike horizontal tunnel shields, here gravity forces debris to accumulate directly in front of the cutting head. For six months, the design team searched unsuccessfully for a solution, until a walk in the park suggested the answer. After seeing the ancient Chinese dragon water wheel (used over 2,000 years ago), engineers created a clever vertical rock transport system. Its performance is equivalent to operating 10 trucks simultaneously.
Another problem is extreme rock pressure and water pressure at a kilometer depth. Without immediate fixation, the shaft walls become deformed or collapse. Together with scientific institutes, the developers created a system for strengthening the trunk in real time.
The machine has already been tested in action. China has built more than 40 coal and almost 20 metal mines deeper than 1 km, of which seven exceed 1.5 km. “Steel Ridge” is designed to make such excavation safer and more efficient, replacing blasting operations with their risks for people.
In addition to mining, similar technologies can be used for the construction of underground protected complexes. Chinese energy experts are proposing the creation of a network of underground structures in the west of the country to protect critical infrastructure.
Chief designer Ding Zhangfei said the team intends to apply the Gante Jiliang to a wider range of applications to help China “seize technological dominance” in deep mining.
Thus, the new drilling machine opens up access to colossal underground wealththat were previously unprofitable or impossible to extract. This is a revolution for the global mining industry: instead of drilling many small holes, you can descend vertically, like an elevator, directly to the ore body.
Source: www.scmp.com
Image: CRCC
