National Mine Map Repository

The National Mine Map Repository (NMMR) is part of the United States Department of the Interior (DOI), Office of Surface Mining Reclamation and Enforcement (OSMRE or OSM). The NMMR resides in the Pittsburgh suburb of Green Tree, Pennsylvania, and collects and maintains mine map information and images for the entire country, including data and maps of coal mines in the anthracite coal region of northeastern Pennsylvania.

Source: Wikipedia — National Mine Map Repository (CC BY-SA 4.0)