This is Brother Slater from Rogue Trader! Also known as Bolter and Sensor.
He appears as Brother Slater in the RT3 flyer in April 1988.
No date on this tab!
Undercoat: Vallejo Mecha Black
Blue: Scale75 Cobalt Blue, highlighted with Primary Blue and Pro Acryl Titanium White
Red: Pro Acryl Bold Pyrrole Red, shaded with Targor Rageshade, highlighted with Bold Pyrrole Red + Pro Acryl Golden Yellow
Silver: Black Metal, Heavy Metal, Speed Metal, shaded with Targor Rageshade
Base: Natural Soil, then Sand, then Gypsum for highlighting the rock
Green: Sap Green, Spring Green mixed with Titanium White