This is a story related achievement and cannot be missed.
SPOILER
Mission: Relic
Once the cutscene finished you will have to go to a huge camp. Grab a vehicle and drive along the street until you come to another outpost (the one with the bridge over the chasm). Once you have done your job there you will be prompted togo to an excavation site. Again follow the street which is kind of hidden. get into the vehicle which is already wating for you: Once you entered the huge dome a cutscene will start and afterwards the achievement should pop.