Magma V Outpost is not one of the largest, but at places can be quite dangerous. Watch out for the Hornet and Weevil in this level. There are a number of steps you must follow to complete the basic objective, and you do not actually destroy this mine in this mission. Try to look for as many secret areas as possible - it could help you throughout the rest of the mission.
Your primary objective is to destroy as many triggers as possible, and then escape the facility. First you need to destroy the trigger above the start point, and then search for two mini-reactors, which you need to destroy to access the triggers behind them.
At this point, you can blast the control panel at the top of the outpost. This will unlock the door blocking your access to the yellow key. With the yellow key, you can destroy two more control panels, then obtain the blue key, and reach the exit room.