Arma Reforger

This one is pretty self-explanatory, but to clarify, you have to be on a non-modded server and you have to place all 20 mines in that same server without disconnecting or leaving. The fastest way to do this is to spawn at a MOB (Main Operating Base) or a spawn point that you know has an ammunition supply point (when you fully zoom in on the map while picking a spawn location you can see what amenities each location is currently providing and what can be constructed) drop your primary weapon and interact with the left arsenal box, this one has explosives and ammo and the right box has medical and gear. Scroll to the last page and pick up 2 mines, if they don't automatically take the place of your primary weapons, move them there (they have to be here for you to properly place them and get credit) and finally, find where you want to place the mines, and select the mine how you would normally pull out a weapon and press right trigger to place. NOTE: You cannot drop them on the ground or drop them, then arm them, the previously described method is the ONLY way to get credit towards the achievement. Now just repeat 10 times and you have your achievement. One big note: Do not rush to equip the next mine while you are placing the first one, if you select it while in the placing/arming animation of the first mine, your game will crash and this counts as a disconnect/leave and you will lose your current progress towards the 20 mines, I unfortunately had this happen on my 19th mine and had to replace all 20 again, so take it slow (I just kept my stick forward, and when my character started moving I placed the next one, because I knew I was out of the animation)