Engebøfjellet: prospect of a major rutile deposit

Abstract

Engebøfjellet is a large rutile deposit within eclogite rock on the northern side of Førdefjord in Naustdal municipality, Sogn og Fjordane county, West Norway.\rThe deposit comprises minimum 300 Mt (million metric tons) of eclogite rock containing 2.5-5 wt% rutile (TiO2, titanium oxide). With an estimated average grade of 3,8 wt% rutile the entire ore deposit contains 11.4 Mt rutile. With a current rutile proce at 675 USD per tonne, the total in-situ value amounts to 8.6 billion USD. With conventional mineral separation processing with 50% recovery, the recoverable rutile represents a value of 4.3 billion USD. Improved mineral processing using novel techniques allows for significantly higher value, perhaps up to 7.0 billion USD.\rIt is likely that adjacent areas north of Førdefjord, particularly eastwards from Engebøfjellet towards Naustdal including the known Steinkrossen deposit, contain additional large amounts of rutile-rich eclogite, similar to Engebøfjellet. Thus, potential additional rutile resources on the north side of Førdefjorden are very significant.\rIn case of rutile extraction with 50% rutile recovery, roughly 98% of the ore comprises mine waste with main silicate constituents garnet, pyroxene, amphibole, etc. The mine waste can safely be deposited, for instance in the adjacent fjord at 300-400 m depth. However, both the bulk availability and the mineral composition of the waste material provide a major opportunity for the development of by-products, increasing value production while at the same time decreaseing the environmental burden.