The Distribution, Character, and Rhenium Content of Molybdenite in the Aitik Cu-Au-Ag-(Mo) Deposit and Its Southern Extension in the Northern Norrbotten Ore District, Northern Sweden

Abstract

Molybdenite in the Aitik deposit and its southern extension was studied through mineralogical/chemical analysis and laboratory flotation tests. It is demonstrated that molybdenite varies considerably in grain size, ranging from coarse (>20 μm) to very fine (<2 μm) and occurs predominantly as single grains in the groundmass of the rocks, as grain aggregates, and intergrown with chalcopyrite and pyrite. The dominating molybdenite-bearing rocks are the mica schists, the quartz-monzodiorite, and the Salmijärvi biotite-amphibole gneiss, the latter containing mostly medium-coarsegrained OPEN ACCESSMinerals 2014, 4 789 molybdenite. Later geological features, such as garnet-magnetite-anhydrite-K feldspar alteration and pegmatite dikes appear to be responsible for a significant part of the distribution pattern of molybdenite. Molybdenite grains contain up to 1587 ppm Re, with an average of 211 ± 10 ppm in Aitik molybdenite and 452 ± 33 ppm in Salmijärvi molybdenite. The higher Re concentrations are found in molybdenite associated with sericite-and quartz-amphibole-magnetite altered rocks, whereas low Re values occur in rocks in which potassic alteration is prominent. Molybdenite recovery is influenced by the mineralogy of the host rock and the alteration grade; hence both of these factors will have an impact on potential recoveries. The recovery of molybdenite was lower from flotation feeds with significant amounts of Mg-bearing clay-micas.

2.5D geophysical model of the Gällivare mining area: An integrated study to model the top 4 km of the subsurface and guide for future exploration activities

“…The Aitik deposit was discovered in 1932 by drilling a geophysical anomaly, and the deposit was further delineated by additional drilling which resulted in identifying a large volume of the low‐grade copper ore. The base metal mineralization has been proven down to a depth between 400 and 800 m. Known as the largest open‐pit mine in Europe, the Aitik deposit extends over 3 km in length, 1.1 km in width and ∼435 m in depth (Wanhainen et al ., 2014) with an annual production of ∼40 Mt (Boliden, 2019). The Nautanen deposit is suggested as an iron oxide copper–gold (IOCG) deposit, and most of the sulphide mineralizations are epigenetic and vary from disseminated to vein style which are hosted within Paleoproterozoic volcanosedimentary units of the Nautanen deformation zone (NDZ; Zweifel, 1976; Martinsson and Wanhainen, 2004a; Wanhainen et al ., 2006, 2012).…”