You should deal with snipers near Kungenga Mine when completing the mission for the first time, because two of them can make it more difficult for you to rescue the children from the mine. There is also an optional objective connected to the snipers. You need to extract all five of them alive to complete it.
Two snipers are located south from the mine, near guard place number 13. Their exact location is marked on the screen above.
There are three snipers located south-east from the mine, near guard place number 2. They are marked on the screen above.
The snipers from each group are located close to one another so they range of view may collide. You have to be very careful not to be noticed. After approaching a given group of snipers, use D-Dog or the binoculars to located them and then start crawling (preferably in some high grass). Approach any of the snipers (from behind or from the side) and put him to sleep without standing up. When you do that, start heading towards another sniper. Fulton the snipers when all of them are knocked out.