Collapsed mines kill three, trap three in Rwanda

* Collapsed gallery traps three in Nyakabingo

* Rock crushes three in Rwanda's Rutongo mine



By Hereward Holland

KIGALI, Oct 26 (Reuters) - Three Rwandan miners remained trapped underground near the capital Kigali after part of the gallery they were working in collapsed on Saturday, the government said on Monday.

In a separate incident a week earlier, three others were crushed to death in a cassiterite and coltan mine in Rutongo, northern Rwanda, said natural resources minister Vincent Karega.

The Rwandan government and foreign companies are investing heavily in the central African country's nascent mining sector, hitherto dominated by small-scale artisanal mining.

Eurotrade Interational and Gatumba Mining Concessions are conducting surveys of old Belgian concessions and are poised to begin industrial mining of cassiterite, coltan and wolfram next year, Karega has said.

"In Nyakabingo, 10 people were locked up in an underground passage which was blocked by a big amount of (fallen) residue. Seven were rescued by local people who dug another quick entrance, three remain inside," Karega told Reuters.

Leonidas Simpenzwe, a geologist at Eurotrade, confirmed three of its miners were still trapped in the Nyakabingo mine.

The small landlocked country's mineral sector represents its second largest foreign exchange earner after tourism, bringing in $91.3 million in 2008, according to central bank statistics.

But the incidents this month highlight the dangers of renovating mines which have lain largely dormant since the end of colonial Belgian rule.

"In Rutongo, three people have passed away. A block of rock crushed them," said Karega.

"Old mines are always risky when you go to rehabilitate because no one knows the risk areas ... more intense mining and the use of explosives have increased in preparation for industrial mining," he said. "We are pushing the companies to strengthen the safety measures." (Editing by David Clarke)