Height of the Tallest Chat Piles in Northeastern Oklahoma

Chat—gravelly waste from lead and zinc mining in the Tri-State District (Oklahoma, Kansas, Missouri)—has accumulated into massive piles across northeastern Oklahoma (Ottawa County). The tallest of these piles exceed 500 feet (150+ meters) in height.

These mountains of mining waste, some covering hundreds of acres, are remnants of the region's early 20th-century boom. They pose environmental hazards (lead dust, heavy metal leaching) and have been the focus of EPA Superfund remediation (Tar Creek Superfund Site). Some stabilized piles are now capped and vegetated; others remain barren landmarks of the area's industrial past.