The pit's cross-section is a fixed radial profile — a bowl-shaped excavation with a berm ring around its rim, h(x) = pit(r) + berm(r) + roughness(x) where r = |x|. Backfilling gradually raises the pit floor toward grade as the reclamation year advances:
filled(x) = h(x) + max(0, year−8) · 0.035 · max(0, −h(x))
cover% = min(98, year·4.2 + soil·0.32 + (rain−250)·0.028)
stability%= min(98, 42 + soil·0.45 + year·1.6)
Vegetation cover depends on time since reclamation began, soil cap thickness (thicker caps hold more moisture and nutrients) and rainfall. Slope stability depends mainly on soil thickness and how long roots have had to establish. When the wetland toggle is on, the deepest part of the pit floods and its water level rises slowly with the reclamation year, capped at a fixed depth; trees only take root on land that stays above the waterline. Tree and shrub density both scale with cover, but trees additionally need years 3+ to establish, so young sites show shrubs first and a forest only fills in later.