The lead and zinc beneficiation plant at Dandi with a capacity of about 140 tons per hour is located 100 km southwest ofZanjan town. Oxidized lead- and zinc ore from the Anguran mine (situated at a distance of 20km from the plant) is used as the feed for this plant. The primary minerals of this mine are cerussite and smithsonite. The plant has been designed to handle two types of feeds i.e. low- and high grade zinc ores. The plant has been equipped and installed from1973-1979. The high grade ore contains 10% lead and 35% zinc while the low grade ore averages 7% lead and 22% zinc. The normal products of the plant include lead concentrate grading 60% lead, zinc concentrate with 38% zinc and a calcined zinc concentrate with 52% zinc. This plant includes the following sections: rock crushing, HMS, milling, filtration and calcination. If the feed is of the low-grade type, it is first upgraded by HMS cyclones and the concentrate obtained is introduced along with the high grade feed into the milling circuit and subsequently concentrated in the flotation unit. Material <2mm in size which is not introduced into the HMS circuit, is milled and added to the low grade flotation route. Finally, after the rougher, cleaner and scavenger stages of the lead flotation route, a concentrate with 60% lead is obtained and the corresponding tailing is dewatered and sent to the zinc concentrate stockpile. A part of the zinc concentrate is sent to the calcination unit to obtain a calcined product containing 52% zinc.