https://www.usa.gov/copyrighted-government-workshttps://www.rawpixel.com/image/12289936Edit ImageSaveSaveEditCropCustom TextPittsburgh, Pennsylvania (vicinity). Montour no. 4 mine of the Pittsburgh Coal Company. Adjusting block signal. Sourced from the Library of Congress.View public domain image source hereMorePublic DomainFree CCO U.S. Government image for Personal and Business useInfoView CC0 LicenseEditorial use only JPEGTIFFSmall JPEG 1173 x 1200 px | 300 dpiLarge JPEG 3420 x 3500 px | 300 dpiBest Quality JPEG 4810 x 4922 px | 300 dpiTIFF 4810 x 4922 px | 300 dpi | 45.18 MBFree DownloadPittsburgh, Pennsylvania (vicinity). Montour no. 4 mine of the Pittsburgh Coal Company. Adjusting block signal. Sourced from the Library of Congress.More