LUSAKA, Zambia (AP) — Authorities in Zambia said Tuesday they were frantically pumping water and mud from a Chinese-owned copper mine where seven miners were trapped underground.

The two Chinese workers and five Zambian ones were caught on Monday when water and mud entered the shaft where they worked at the Macrolink mine in Ndola, about 400 kilometers (248 miles) from the capital, Lusaka. Another miner escaped.

Copperbelt Province police commanding officer Peacewell Mweemba told The Associated Press that authorities were mobilizing equipment from various mining companies for what they hoped was still a rescue mission.

“For now, we are still hopeful that they are still alive,” he said.

Local media reported that the miners were working at around 235 meters (257 yards) underground.

Local media reported that the miner who escaped, Penjani Kaumba, said he noticed water coming from a tunnel and immediately informed colleagues, but it was too late.

Zambia is one of the world’s largest copper producers, and Chinese firms have invested billions of dollars in mining there.

Another mine accident in Zambia in November killed at least 11 people, with others missing.