Great TR, as always. Also as always, CA and NV provide some great geology. The Blue Sphinx is the type locality of the Blue Sphinx tuff, an otherwise unremarkable Tertiary quartz latite tuff. As usual, the mining stuff appeals to me the most, especially with the plans to visit Terlingua, TX towards the end of the year. In its heyday, the Terlingua District produced around 25% of the US supply of mercury. At the Poinsettia Mine, NV, as at many of the Terlingua mines, a simple retort was erected to extract the mercury in its elemental liquid form. Cinnabar is mercury sulfide and the mercury metal is readily extracted by crushing the ore crudely into gravel-sized chunks, charging an iron cylinder with the crushed ore, and heating the vessel. The mercury boils at around 700 deg F so the resulting mercury vapor rises up through the inclined vessel and is captured and directed through a condenser coil to become liquid mercury at room temperature. Thus the retort is a crude distillation process. The distilled mercury was captured in an iron flask with standard weight of 76 lbs. Due to its high density, a flask of mercury is only around 2 liters (roughly a half gallon) of liquid metal. With the relatively simple/crude milling requirement and similarly simple/crude distillation process to recover the metal, there was no reason to transport the ore long distances, so many mines had milling and distillation facilities on site.
Foy
