Fine milling of Stoilensky oxidized quartzite

Abstract

The development and technological advance strategy of Stoilensky GOK (Mining and Processing Plant) includes modernization of crushing and milling facilities. The top-priority objective in this regard is resource-saving based on higher energy efficiency of ore pretreatment. The pretreatment process flow is added with high pressure grinding rolls (HPGR) manufactured by Köppern, Germany. The test subject is ferruginous quartzite from Stoilensky deposit. This is a finely disseminated and very strong rock. Dissociation of metal and nonmetal phases takes place in milling to the size of –0.045 mm. Milling was implemented in three stages, with preliminary size screening of stage III product, which offered a finely milled product with the weighted average size dav of 5.5 mm at the content of size +15 mm up to 2.5 %. Some aspects of the roller technology introduction are discussed, and the main stages of the technology application at the commercial scale are described. The informational measures are selected to compare ferruginous quartzite pretreatment circuits with and without HPGR. Fine milling enhances efficiency of processing by 8 % owing to the reduced size of feed of the head-end mills at the maintained iron ore concentration quality.