Multi-Element Ratios to Define Estimation Domains: Kvanefjeld REE-U-Zn Deposit

Robin Simpson
Tuesday, October 1, 2013
First presented: 
AusIMM Bulletin

Kvanefjeld is the flagship orebody of Greenland Minerals and Energy Ltd’s (GMEL) Northern Ilimaussaq Specialty Metals Project. The project contains the world’s largest Mineral Resource of rare earth elements reported according to the standards of the JORC Code or NI 43-101, and one of the world’s largest uranium resources. Mineral Resources are given in TABLE 1. Prefeasibility work on the project was completed in 2012, and feasibility studies are underway.

The host rock for Kvanefjeld mineralisation is lujvarite – a form of nepheline syenite unique to the Ilimaussaq Complex in southern Greenland. The lujavrite occurs in a shallow dipping layer from about 250 m to over 500 m in thickness and extends laterally for several kilometres. The other main rock type in the area is naujaite, also a nepheline syenite. The visual contrast between the dark lujavrite and the lightly coloured, nonmineralised naujaite makes it easy to identify the contacts of mineralisation in core or during mapping. A challenge for GMEL was to identify higher grade zones within the lujavrite that could be accessed at the start of the mining schedule, to improve the economic viability of exploiting a large but essentially low-grade orebody. Delineating zones of common chemistry and ore mineralogy were also of importance, for focussing metallurgical studies and guiding the choice of processing methods.

Early work to establish criteria for subdividing the lujavrite, based either on core logging or statistical analysis of uranium and rare earth element (REE) grades, yielded inconclusive results. Initial resource estimations for Kvanefjeld were based on a single estimation domain, resulting in smoothing of local grade variability.

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