Rocks. The building blocks of a civilized society. Without rocks you can't make concrete. And without concrete you can't make buildings. At least not a building worth being in.

A quarry has been located that serves as Red's primary source of gravel for concrete mixing. A mostly autonomous facility primarily run by droid labor, the lack of a human presence should make it an easy target. With a forward base set up all that's needed is a well positioned payload pushed along Red's rail lines, and their construction capabilities will be immediately halted.

Our sources have indicated traces of Australium on site as well. It appears that due to an over specificity in the droids programming only requiring them to collect stone, they've begun hoarding bits inside of their private quarters. Once the mission is complete the droids can be retired and the full source of Australium can be extracted.