P.O. Box 643
47 Cox Gulch Road
Thompson Falls, MT 59873

NYSE: UAMY

Phone: 406-827-3523
Fax: 406-827-3543
Email: tfl3543@blackfoot.net

TERMINOLOGY

• “Hand sort” (considered “direct furnace feed”) in Mexico is typically oxide ore (the mineral is senarmontite or valentinite) that has been upgraded by hand sorting to a grade of 30-60% contained antimony. Alternatively it can be sulfide ore (the mineral is stibnite) that has been upgraded by hand sorting to 30-60% contained antimony. Hand sort  from Mexico is often a mixture of sulfides and oxides.
   

• “Sulfide concentrates” are usually flotation concentrates produced in a mill that will range from 50-68% contained antimony. The mineral is usually stibnite and the theoretical maximum antimony content is 71.1%. Recoveries from flotation mills are generally 80-95%.
   

•  “Oxide concentrates” are produced using gravimetric methods such as jigs, tables, and spirals. They are generally either senarmontite and/or valentinite that are both antimony trioxide with a theoretical maximum antimony content of 83.53%. Gravity concentrates are typically much lower grade than sulfide concentrates and are in the 25-40% antimony content range. Recoveries from oxide plants are generally less than 50%.
   

• “Crude” means crude antimony trioxide, typically 82.5% antimony metal contained. The desirable mineral is senarmontite. This can be refumed directly to “finished” oxide or converted to metal, or sold directly as a feed for other plants. It is typically an off-white color (gray or light brown).
   

• “Finished” means finished antimony trioxide. It typically is senarmontite and has an antimony content of  82.5 –83.3%. It is brilliant white.
   

•  “Fuming” refers to the process of fuming hand sort, oxide concentrates, sulfide concentrates, or crude to either crude or finished.
   

• “Reduction” refers to reducing oxide hand sort, sodium antimonite or crude to metal. Carbon is generally used.