In Jak II, Jak visited this location on multiple occasions. On one, the Metal Heads placed clusters of eggs all across the Platform that drained Eco power, but they were destroyed by Jak. Jak later destroyed the Main Control Tower with the Titan Suit, making it more difficult to operate. Jak also destroyed a Haven Tanker Ship.
The Drill Platform is a massive Haven City mining operation equipped with a massive drill that's mining in the mountains for Eco. It is held up with spider-like legs. The Drill Platform is located in the mountains west of Haven City and probably in the Icelands. It was also a docking area for Haven's Tanker Ships, one of which was destroyed by Jak.
There are apparently numerous Drill Platforms though, as seen in concept art.
There were many defence turrets - Gun Pods - as Jak used multiple in his missions on several occasions. There was also a Titan Suit, which could have been used as a means of defending the location. Despite its fortification, Drill Platform fell under the control of the Metal Heads.