Abstract: Tailings generated by mining account for the largest world-wide waste from industrial activities. Copper is relatively uncommon, with low concentrations in sediments and waters, yet is very elevated around mining operations. On the Keweenaw Peninsula, 140 mines extracted native copper from the Portage Lake Volcanic Series, part of an intercontinental rift system. Between 1901 and 1932, two mills at Gay sluiced 22.7 million metric tonnes of copper-rich tailings into Grand Traverse Bay. About 10 MMT formed a beach which migrated 7 km to the Traverse River Seawall. Another 11 MMT are moving underwater along the coastal shelf, threatening Buffalo Reef. Remote sensing techniques documented geospatial environmental impacts and initial phases of remediation. Aerial photos, ALS LiDAR/MSS surveys, and recent UAS overflights aid comprehensive mapping efforts. Because natural beach quartz and basalt stamp sands are silicates of similar size and density, percentage stamp sand determinations utilise microscopic procedures. Copper leaching is elevated by exposure to high DOC and low pH waters, characteristic of riparian environments. Lab and field toxicity experiments, plus benthic sampling, all confirm serious impacts of tailings on aquatic organisms. Mining companies should end coastal discharges and also adopt the UNEP “Global Tailings Management Standard for the Mining Industry”.