From Halopedia, the Halo wiki
The Red Slate Plateau was a plateau on the human colony of Draetheus V. During the Battle of Draetheus V, Covenant forces had gathered at the plateau. After the remainder of the 23rd Armored Cavalry and Spartan Sarah Palmer made their way across the bridges on Epsilon Expanse, UNSC forces engaged the Covenant. M808 Scorpions and M850 Grizzlies from the 23rd Armored Cavalry battled Covenant Type-26 Wraiths on the plateau. Following the engagement, only eight of cavalry's eighty-six vehicles remained. Later in the battle, Covenant forces overran the position once again.
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