"Ahu" are stone platforms on which many moai sit. There are 313 known ahu and 125 of these carry moai. The biggest, Ahu Tongariki is 220 m (720 ft), and had the most (15) and tallest moai.
Of the 55 refineries closed in America in the last 10 years, they were all closed for economic reasons, mostly oil company mergers. Not a single one was closed for environmental purposes or objections.