A court in the Democratic Republic of Congo has sentenced three Chinese nationals to seven years in prison for engaging in activities related to illegal mining.

The court, in Congo’s eastern city of Bukavu, the capital of Congo’s gold-rich South Kivu province, sentenced the men late Tuesday for the illegal purchase and possession of minerals, money laundering and other offenses.

The suspects were found in possession of $400,000 in cash and a substantial amount of gold on Sunday, raising concerns about the scale of their operations and the potential involvement of organized networks.

Speaking to reporters on Monday, the governor of South Kivu province, Jean Jacque Purusi, said people there are tired of those who plunder the country’s resources.

“This is only one-tenth of what they have already taken from us. We will not let it go. This is the wealth of the people of South Kivu. We are determined to go all the way because enough is enough,” Purusi said.