On Saturday morning the kid and I arrived in Jamestown, Colorado, in search of mill sites and mine tailings. It does have a post office, but unlike many mountain towns it has managed to remain free of yuppie development. No Aspenization … yet.

This mining district lies on the northeastern extreme of the Colorado Mineral Belt. Once a hotbed of gold and silver mining, the area also produced considerable U3O8 and separately, fluorspar. Au and Ag ore bodies were enriched in copper, zinc, lead (galena), fluorite (CaF2), gold, silver, arsenic and tellurides.

UraniumCore announced in December of 2006 its purchase of 60 % interest in 88 claims in Colorado, including 46 unpatented claims in the Jamestown area. As seems to be the case in most minerals exploration activity in Colorado that I am aware of, the action is being driven by Canadian, Australian, and South African companies. The prinicpals heading up UraniumCore are Canadian.

While my brother-in-law is Canadian and while I would actually like to retire in BC, I can’t help but say that I would like to see more US companies involved in mineral exploration. There has to be a back story here.

Initially we tried to visit the 11 acre Burlington fluorspar mine site. This site was the focus of some environmental trouble for the locals in Jimtown. Unfortunately, the site was thoroughly fenced off, so interesting photos were not to be had. According to one website, Honeywell has completed remediation of the site.

Driving back towards Jimtown from the Burlington mine the kid spotted some old timbers jutting out of the hillside, so we stopped. Following what could only be a tiny stream of tailings runoff (having orange iron sediment) we found the remains of a mill site along a small creek.

Jamestown Fluorspar 9-26-09 near Burlington Mine

Jamestown Fluorspar 9-26-09 near Burlington Mine

On the tailings pile we found some purple fluorspar and some rocks which under magnification, resemble gold ore I have seen elsewhere. There was the familiar sulfide odor in the area indicating the presence of surfaces of unoxidized sulfide minerals.

Fluorspar is used in iron and steel manufacture in quantities of up to 10 kg/ton of steel. Limestone and dolomite are added to molten iron in the steelmaking process (fluxing) to bring impurities out into a slag phase. We synthetic chemists have an analogous situation with “rag layers” or emulsions. Near as I can tell, slag resembles lava in the sense that it is a molten silicate.

Metallurgists apparently have to provide conditions for extraction and phase separation of unwanted components in a melt. A slag phase may be rich in silicates among other things. According to references I have seen, fluorspar is added to the mix as a fluxing agent to “increase the fluidity” of the slag, which I interpret as causing a decrease the slag viscosity. Whether this is purely a rheological effect or also a sequestering effect is inclear at present to me.