The dark wooden timber platform above the public? No, it's a raised keeper area for hosing down the mountain, the white structure you see up there houses a fire hose. The mountain is hosed down every morning from this vantage point. Due to OH&S regulations, keepers are not permitted to climb on the mountain without explicit permission from management, and only for special circumstances. As the concrete can be slippery when wet, it's a fairly good rule. So the mountain gets hosed from an elevated position outside the enclosure. Luckily, tahr defecate small pellets which easily wash down the mountain.
I was lucky enough to climb the mountain some time ago (with the required permission) and the view from the top is spectacular.
