Eleanora I. Robbins 1999 <p>Acid drainage from abandoned coal mines is affecting thousands of miles of rivers in the eastern United States.&nbsp;U.S. Geological Survey (USGS) scientists are finding that neutral drainage is sometimes being mistaken for acidic drainage because both involve the formation of iron oxide-rich materials.&nbsp;USGS scientists are adapting microbial techniques to learn about the processes that form the acidic and neutral iron oxide-rich flocculates and&nbsp;are developing spectral reflectance techniques that differentiate between acid and neutral materials.&nbsp;Federal and State regulatory agencies are using these data to help make land-use decisions.</p> application/pdf 10.3133/fs11899 en U.S. Geological Survey Microbial and spectral reflectance techniques to distinguish neutral and acidic drainage reports