Bertha mine. Rico district. Colorado Description. R.M.News.Sept.21,1879.p.4 c.1 production; description. R.M.News..Tuly 9,1880. p.3 c.2 Strike made; estimated output. R.M.News.Tune 14,1881 p:2 c.3 Description, Silver creek. R.M.News.Nov.17,1881 p.4 c.4 . Location; description; assay. R.M.News. May 28,3881 p.4 c.4 Description, Nigger Baby hill. R'M.NOws Mar. 8, 1981 p. 2 c. 2 0