The Industrial Terrain from GrimDark Terrain is compatible with 6-8 mm Epic Sci-Fi games. It fits perfectly into your terrain. Whether Warhammer 40K or other sci-fi tabletop games, it simply fits many settings.The Underground Promethium Dump consists of 10 parts and measures approximately 158x158x35 mm. You can find assembly instructions here:
https://grimdarkterrain.com/template-construct/stc-103-pyraeus-underground-dump/
We have many other terrain models and also Greebles/Bitz on offer. Just take a look around.