Born-Digital or AnalogAnalogTranscriptRobert B. tunnel Irwin district. Colorado Development; description; character of ore R.M, News. Dec. 11, 1883 p.1 c.1 Rich strike described RX. News. Jan. 13, 1884 p.8 c.3CollectionWestern History Subject IndexRelated MaterialWestern History Subject Index AbbreviationsType of MaterialIndex CardLanguageeng
Robert B. tunnel Irwin district. Colorado, [527409]. Denver Public Library Digital Collections, accessed 25/01/2026, https://digital.denverlibrary.org/nodes/view/1637365
