Rawlins Paint Mines

Rawlins Paint Mines. . , The hills located to the south and west (your left) are part of the Rawlins Uplift, a 40 mile long, north trending fold in the earth's crust. The geologic feature rises a thousand feet above the surrounding plains. Granite rocks that range in age from 2.6 billion years to 10 million years are exposed along its crest and slopes. The reddish rocks that comprise much of the distant hills are the Flathead Sandstone (Cambrian) which is 520 million years old. The grey strata that overlie the Flathead Sandstone are part of the Madison Limestone (Mississippian Period), a 360 million year old rock unit. Both the Flathead Sandstone and Madison Limestone were deposited in shallow seas which once covered this area. The Flathead Sandstone contains hematite, a red iron mineral, that was mined in this area from 1870 to the early 1900s. , The now abandoned mines were located in the rock outcrops located a mile to the south of this sign. Some of the mined hematite was used as a "barn red" paint pigment noted for its durability and covering qualities. This popular "Rawlins Red" enjoyed the distinction of being selected in 1893, as paint for the newly constructed Brooklyn Bridge. Hundreds of tons of ore were extracted annually between 1879 and 1886, and the paint made from it was used all across the country on a wide variety of building and structures. Cost increases for extracting, shipping and processing the ore as well as technical advances in paint manufacture eventually led to permanent closure of the mines.