Abandoned mines in Colorado

A USGS feature is a symbol on a historical topographic map, there when the map was surveyed; it may since have been sealed, reclaimed, built over or reopened, and the map does not say which. An OSMRE row is a problem the abandoned mine land program tracks, not a mine, and several problems make one problem area (PAD), which is the unit a state program counts and reports; the public extract can also hold more problem areas than a state's live inventory, because areas since merged or ruled ineligible stay in the published file, so a state figure that differs from this one is not a contradiction. An MSHA mine is a registered operation whose operator reported abandonment, a record that starts in the 1970s; that is a regulatory status rather than a physical one, and it also holds operations merely between jobs, portable crushers above all, which is why over a thousand mines carrying it have been inspected in the last two years. The three overlap and are never added together. Counties are assigned from each feature's coordinates against the Census 2023 county boundaries. The full method and every source are on the national page.