Complex sentence: These rats are also becoming useful in some areas for detecting land mines: their acute sense of smell is very effective in detecting explosives such as TNT, and at the same time they are light enough to not detonate any of the mines.
Split into simpler sentences: These rats are also becoming useful in some areas for detecting land mines, as their acute sense of smell is very effective in detecting explosives such as TNT. They are light enough to not detonate any of the mines.