![](http://upload.wikimedia.org/wikipedia/commons/thumb/e/e9/VKG_Ojamaa_kaevandus.jpg/340px-VKG_Ojamaa_kaevandus.jpg)
Photo credit: Greenpeace
Oil shale is a source of unconventional oil, which combustion and thermal processing generate atmospheric emissions. Pictured is oil shale being mined by the Viru Keemia Grupp.
Photo credit: Greenpeace
Oil shale is a source of unconventional oil, which combustion and thermal processing generate atmospheric emissions. Pictured is oil shale being mined by the Viru Keemia Grupp.