A few Andreas Feninger photos found at the Library of Congress are shown below.The New Idria mine was a productive mine and smelting operation in central California.Note the fellow at the tiltedsorting table, physically agitating the mercury from the solid soot and allowing it to run down the table for collection. This is a gravity sorting process. Hard to know what kind of occupational exposure the poor fellow is into.
Worker collecting mercury from soot from smelter at New Idria mine, ca 1942. Library of Congress.
Since the early days of Spanish mercury trade, mercury has been packaged in iron flasks. According to my sources, the 76 lbsizing of the flask was based what laborers and pack animals could plausibly carry all day. In the picture below, a flask is being filled with mercury at the New Idria smelter.
Mercury Filling Station at New Idria Mercury Smelter, 1942. Photo by Andreas Feninger, Library of Congress.
Cinnabar ore was crushed and then roasted in a rotary kiln. This process not only released the sulfur from the cinnabar (HgS), but also decomposed the oxide and volatized the mercury. The mercury vapor was knocked down from the exhaust gas in condensers.
Rotary Kiln at the New Idria Mine and Smelter, 1942. Photo by Andreas Feninger, Library of Congress.