https://creativecommons.org/publicdomain/zero/1.0/https://www.rawpixel.com/image/12148869Edit ImageSaveSaveEditCropCustom TextTimbered tunnel leading into mine. San Juan County, Colorado. Barren mountain sides attest to the amounts of timber which was used in construction of such tunnels as this by Russell LeeView public domain image source hereMorePublic DomainFree CC0 image for Personal and Business useInfoView CC0 LicenseJPEGTIFFSmall JPEG 1200 x 916 px | 300 dpiLarge JPEG 3500 x 2672 px | 300 dpiBest Quality JPEG 14147 x 10800 px | 300 dpiTIFF 14147 x 10800 px | 300 dpi | 145.81 MBFree DownloadTimbered tunnel leading into mine. San Juan County, Colorado. Barren mountain sides attest to the amounts of timber which was used in construction of such tunnels as this by Russell LeeMore