That's what a lot of people have been asking as they've witnessed low-flying helicopters carrying a large hoop-like device overhead. Low Flying Helicopters Surveying LandI saw a post on Facebook that showed images from a door camera over Esko. The United States Geological Survey issued a press release earlier this summer about planned helicopter mapping flights over the region. The helicopters are using airborne geophysical technology to survey the Lake Superior Basin in western Michigan, Northern Wisconsin, and northeastern Minnesota. USGS.GOV USGS.GOVUSGS Looks To Find GraphiteOne of the minerals the USGS is looking for is graphite.