A recently launched iron ore mine in China's northeastern Heilongjiang province flooded May 17 leaving nine workers trapped underground, Reuters reported, citing Chinese state media.

The flood at Xilin Iron & Steel Group Co. Ltd.'s Cuihongshan mine in the city of Heihe, on the border of Russia's Amur Oblast, occurred at around 3 a.m. while 43 people were working underground, according to China Central Television.

China's second-largest privately owned steel company, Jianlong Steel Holdings Co. Ltd., bought Xilin Iron & Steel in 2018.

By 3:40 a.m. GMT, 34 of the miners had been rescued, but nine remained trapped below ground. The local government dispatched 300 rescuers to save them.

The Cuihongshan mine has an annual capacity of 1.6 million tonnes and reserves of 70 Mt of iron ore and 80 Mt of nonferrous metals.

Operations began in February at the mine, which has an annual magnetite output capacity of 850,000 tonnes, iron-zinc capacity of 700,000 tonnes and lead-zinc-copper capacity of 50,000 tonnes, according to the website of Xunke county, where the mine is located, Reuters added.

While still under construction, the mine clocked up 26 safety violations in 2017, briefly halting building work to improve safety conditions.