Six records break an international monopoly, and a Chinese deep-sea heavy-duty operations mining vehicle passes 4,000 meters of sea trial depth for the first time.
Touching down at 4,102.8 meters and successfully recovering deep-sea polymetallic crusts and nodules, Kaituo 2 (Pioneer 2), the deep-sea heavy-duty operations mining vehicle engineering prototype independently developed by Shanghai Jiao Tong University, recently returned to Xiamen aboard the Xiang Yang Hong 03 research vessel after completing its deep-sea trial voyage, with the sea trial a complete success. Over five prospecting and mining dives, Kaituo 2 set six records in China’s deep-sea mining field, with technical performance assessed as leading domestically and advanced internationally. The result is a major breakthrough by Shanghai Jiao Tong University, serving the national maritime power strategy and the building of Shanghai as a science and technology innovation center and modern marine city, in organized research on key technologies for deep-sea heavy-duty operations equipment through the Shanghai Changxing Marine Laboratory, a new type of research institution centered on high-end marine equipment development.
Five dives: a Chinese deep-sea heavy-duty mining vehicle passes 4,000 meters in sea trials for the first time.
The ocean floor holds rich mineral resources such as polymetallic nodules, cobalt-rich crusts and polymetallic sulfides, containing copper, cobalt, nickel, manganese and other important critical materials of very high application value. Deep-sea mineral resource development is a quintessential marine high-technology industry, combining deep-sea engineering technology, ocean science exploration and green development of marine resources. It will drive frontier and disruptive technology research across many marine industries, create new points of industrial growth, and provide new momentum for the national economy and social development.
“The seabed terrain is rugged and sea conditions are complex. Seabed mining equipment must not only move freely in such an environment, it must also be able to extract and collect minerals and be recovered effectively. Every one of these steps has to pass the test of sea trials,” said sea trial chief scientist Yang Jianmin, professor at Shanghai Jiao Tong University’s School of Naval Architecture, Ocean and Civil Engineering. He explained that deep-sea mining has long faced three major technical challenges internationally: first, seabed terrain in mining areas is extremely complex, making safe equipment movement difficult; second, deep-sea minerals occur in complex and varied forms with diverse physical properties, making efficient extraction and collection difficult; third, deploying and recovering heavy-duty deep-sea equipment in wind and waves at sea is difficult.
In this deep-sea trial, Kaituo 2 completed five consecutive successful dives in seabed polymetallic crust and nodule areas, one to the 4,000-meter class and four to the 2,000-meter class, reaching seabed depths of 1,802.4 meters, 1,929.9 meters, 1,955.8 meters, 2,048.5 meters and 4,102.8 meters. This was the first time a Chinese deep-sea heavy-duty operations mining vehicle carried out trial extraction of deep-sea mineral resources on the seabed below 4,000 meters. Kaituo 2 also demonstrated powerful seabed rock drilling and collection capabilities, efficiently extracting and collecting different types of seabed minerals, from polymetallic crusts tightly bonded to hard bedrock to polymetallic nodules shallowly buried in soft deep-sea sediments, and successfully recovered more than 200 kilograms of deep-sea mineral samples of various types, including polymetallic crusts, polymetallic nodules and seabed bedrock.
Six breakthroughs: moving and mining across rugged seabed terrain as if on flat ground.
Whether on steep, rugged seamounts with slopes of more than 30 degrees or on seabed flats of highly viscous, soft sediment, Kaituo 2 was able to drive, climb and turn in place smoothly. To give the mining vehicle freer movement, the team developed technology that requires no human operation: the vehicle autonomously senses the mining environment, and its four tracks adjust their direction and state in real time according to the actual seabed terrain, adapting to complex seabed conditions, a first in China.
According to the team, the development of Kaituo 2 achieved six firsts among comparable Chinese research programs. It raised the deployment operating depth of a deep-sea heavy-duty operations mining vehicle past the 4,000-meter mark for the first time, to 4,102.8 meters, and recovered large quantities of deep-sea mineral samples including polymetallic crusts and nodules. It pioneered high-mobility driving technology for complex deep-sea terrain, achieving safe, stable movement across steep seamounts of more than 30 degrees, soft deep-sea sediments and other complex seabed terrain. It pioneered multi-mineral composite drilling and extraction technology, enabling efficient extraction and collection of different ore types such as polymetallic crusts and polymetallic nodules. It pioneered intelligent fine control technology for deep-water heavy-duty operations, providing intelligent path planning, tracking and obstacle avoidance, and achieving centimeter-level positioning accuracy in deep water. It pioneered non-metallic cable deployment and recovery technology for deep-sea heavy loads, deploying and recovering heavy equipment at 4,100 meters of water depth with safe working load among the highest in China. And it innovated technology for monitoring and assessing disturbance to the deep-sea environment: the vehicle carried an environmental monitoring system that comprehensively tracked and assessed the generation and spread of seabed plumes, underwater operating noise and other environmental impacts, providing valuable first-hand material and data for China’s deep-sea mineral exploration and green, environmentally sound extraction.
Huang Wei, deputy head of the deep-sea geology and minerals office at the Qingdao Institute of Marine Geology, who joined the sea trial aboard ship, said Kaituo 2 can extract deep-sea polymetallic crust ore efficiently and stably. For crusts attached to sloping bedrock, its cutting capability can rapidly separate crust from bedrock and draw the crust ore into the collection bin efficiently. The vehicle’s slope-climbing and obstacle-avoidance capabilities also allow it to work in multiple directions over complex terrain, covering a crust mining area extensively and improving ore recovery. Deployment and recovery of a deep-sea mining vehicle is a recognized technical difficulty, he added, and Kaituo 2 operated for five consecutive days in force 6 winds and sea state 4, successfully completing multiple consecutive deep-sea deployments, seabed operations and lift recoveries, proving the equipment’s safety and reliability.
From the laboratory to the open sea, the program is the product of a decade of work by three generations of naval architecture and ocean engineering researchers.
“In 2013, overseas development of deep-sea mining equipment had already reached a certain level, but related development in China had barely started. I felt then that China needed to fill the gap in deep-sea prospecting and extraction,” said Yang Jianmin, chief scientist of the Kaituo series of deep-sea mining vehicles, who has spent ten years taking the program from an initial concept to blue-water sea trials. Leading his team to address major national strategic needs, he successively developed the deep-sea heavy-duty operations mining vehicles Kaituo 1 (Pioneer 1) and Kaituo 2. Kaituo 1 successfully completed a 1,305-meter deep-sea trial in 2021. The new-generation Kaituo 2 consists of the mining vehicle itself, a high-capacity opto-electric composite umbilical cable and a heavy-load deployment and recovery winch, among other equipment. It is 6.0 meters long, 3.0 meters wide and 2.5 meters high, weighs about 14.0 tonnes, and has a design operating depth of 6,000 meters, with the ability to extract multiple mineral types including polymetallic crusts, polymetallic nodules and deep-sea sulfides. Its technical performance is assessed as leading in China and first-class internationally.
Over the decade of development, the team steadily added new talent. Ten years ago, Zhao Guocheng was a graduate student at the School of Naval Architecture, Ocean and Civil Engineering who chose deep-sea mining as his research direction under his advisor’s influence; he joined this sea trial as a young core faculty member. “From tank tests in a few meters of water in the laboratory to seabed mining operations at thousands of meters of depth on this trial, I gained invaluable learning and training. The sea trial results are inspiring, and I am more certain than ever that deep-sea mining will be my future research direction,” he said.
“The Kaituo 2 sea trial is a system-level project. It tests not only the mining vehicle’s performance in the high-pressure deep-sea environment but also poses a major challenge for the heavy-load deployment and recovery system. The mining vehicle, the opto-electric composite cable and the winch had never been verified at sea, so we faced many uncertainties,” said team member Liu Mingyue, associate professor at the School of Naval Architecture, Ocean and Civil Engineering. During the sea trial, three generations of the university’s naval architecture and ocean engineering researchers worked across disciplines to solve one problem after another.
In recent years, Shanghai Jiao Tong University has served the national maritime power strategy and the building of Shanghai as a science and technology innovation center and modern marine city through its “Greater Marine” strategy, pooling disciplinary strengths to build a cross-disciplinary innovation research platform for marine equipment. In 2019 it was approved to build the Ministry of Education’s integrated research platform for deep-sea heavy-duty operations equipment, and on that basis it was approved in 2021 to establish the Shanghai Changxing Marine Laboratory, a new type of research institution centered on high-end marine equipment development that is building a quasi-industrial laboratory, with deep-sea equipment and resource development among its four priority research directions.
The successful development of the Kaituo series of mining vehicles will help make the Shanghai Changxing Marine Laboratory an important research base for China’s deep-sea mining technology. Going forward, the university will continue to use the Greater Marine initiative to consolidate key technology research results, steadily advance the development of high-end deep-sea mining equipment, and work toward the transfer of results into products and industry.
