Economical Potential of an Ultramafic Rock at the Kvaløya Island, North Norway

Abstract

A low-grade metamorphic ultramafic rock at the Kvaløya Island, North Norway, shows Ni content up to 5,600 ppm and an average content of 2,500 ppm Ni. Olivine is absent from the rock, and Ni is principally bonded in pentlandite, violarite, and millerite. The rock might be considered as a low-grade ore, with 0.2–0.56 wt% Ni. Other metals that might be of economic interest to extract from the rock include Co (from pentlandite and violarite) and Cr and Fe (from magnetite).

However, traditional mining of such a low-grade ore would result in large volumes of waste material, which could represent a serious environmental problem. The future challenge for developing low-grade ore deposits like this is to find alternative uses of the minerals that are left after extraction of the economically interesting ore minerals, in order to reduce the volumes of waste materials from mining. One possible use of many of the traditional waste minerals from mining is for CO₂ sequestration, i.e., by reacting the waste minerals with CO₂ in order to permanently store CO₂ in carbonates. Traditional mining of the Ni-bearing ultramafic rock described here would result in large volumes of tailings dominated by serpentine. If value could be added by reacting serpentine from these tailings with CO₂ in order to sequestrate CO₂ in magnesite, extraction of Ni from such a marginal grade deposit could be of economical interest.