Rutile ore characteristics, Engebøfjellet.

Abstract

During the DuPont\/Conoco\/NGU Engebøfjellet project (1995-97) 49 boreholes were drilled, altogether 14527 meters. All cores were analysed forTiO2 and Fe2O3 using a portable XRF instrument (Dutokumpu X-Met); approximately 50.000 X-Met analyses were made. \rA number of core sections, for most of the drill hoies one 10m-section per 100 m core, were also analysed in the laboratory by a combined XRF and ICP-AES \"rutile analytical procedure\" in which rutil was determined as the difference between TiO2 (total,analysed by XRF) and Ti O2 (acidsoluble, analysed by ICP-AES), giving precise information about total whole-rock TiO2 and other major elements, and semi-quantitative information of the amount of rutile present.\rThe X-Met (XRF) core analyses in combination with surface analyses were the basis for a 3D-model ore resource developed by DuPont.\rEvaluation of the analytical data from the DuPont-project confirms that the core analyses carried out by the X-Met portableXRF are semi-quantitative. Adjusted X-Met data based on comparison with reference XRF analyses, give a correct overall picture of the TiO2-distribution along the cores as well as providing reliable average numbers for large coresections, but they are not reliable on meter-scale and are only indicative on 10-meter scale.