The suspects were caught mining coltan and cassiterite in a stream.
Those arrested are Vincent Habiyambere, Claude Twagirimana, Venuste Hakorimana and Vincent Nshimiyimana.
Others are Adrien Sinayobye, Patrick Mugabo and Sylidio Habirora.
According to Chief Inspector of Police (CIP) Bonaventure Twizere Karekezi, the Police spokesperson of the Western region, the operation was conducted between 11AM and 12:30 following information from local residents, who reported the unlawful acts.
"Local residents called Gatumba Police station reporting a group of people that was conducting illegal mining activities, which were affecting the stream and the environment in general," CIP Karekezi said.
"The Police station and local administrative security personnel worked together to arrest all the seven people red-handed.
Their unlawful mining activities had affected the stream, blocked and channelled the running water to people’s gardens and the waters turned dirty due to such human actions," he added.
The spokesperson noted that all the seven illegal miners came from different places, were not wearing facemask and protective gears.
"In any unfortunate case where one is infected with COVID-19, it was easy to infect others. They were also exposed to health risks since they had no protective gears.
Besides, they were also using minors in the unlawful and hazardous acts of mining."
The exhibits including minerals and the tools they were using, were impounded at Gatumba Police station where the suspects are detained.
CIP Karekezi thanked the residents for reporting the illegal practices to protect the stream and fight environmental degradation.
Last week, more than 40 people were also caught in illegal mining activities in closed coltan concession located in Rutsiro District, Rusebeya Sector in Kabona Cell.
The concession was closed on safety grounds.
Article 54 of the law on mining and quarry operations, states that; “any person, who undertakes mineral or quarry exploration, exploitation, processing or trading without a license commits an offence.”
Upon conviction, the offender is liable to imprisonment for a term of between two and six months and a fine of not less than Rwf1 million and not more than Rwf5 million or only one of these penalties.
The law also provides for the confiscation of any seized minerals or quarry in storage, trading or processing without a license.