The Department of Geochemistry has been engaged, since 1991, in an extensive study of Niobium ores and related rocks, in the framework of two EC-Funded BRITE-EURAM projects, directed successively on two targets: first on the Lueshe Mine in North Kivu (Congo Dem. Rep.), and, from 1996, on deposits related with the Sokli carbonatite complex in Eastern Lapland (Finland).

1991-1993: Applied mineralogy of pyrochlore and related minerals in the weathering zones of the niobium deposits of the Lueshe and Bingo carbonatites, Zaire.  EC Contrat MA2M - CT90-0038.

1996-1999: Development of new technology for utilisation of the unique Nb deposit at Sokli, Finland, for the European super-alloy industry. EC Contract BRPR-CT95-0015 (DG 12 - RSMT)

The objective of these projects, under the guidance of industrial partners from Germany (Gesellschaft für Elektrometallurgie, Nuernberg, for both projects) and Finland (Kemira Oy, for the Sokli project), has been the precise characterization of the ores, as a prerequisite for the optimisation of the beneficiation processes.

The objective has been completed through a close cooperation between the three teams engaged in complementary analytical programs:
• XRD quantitative determination of modal compositions: Département de Minéralogie, Louvain-La-Neuve University, Belgique;
• mineral compositions: EPMA at British Museum of Natural History, London;

XRF and ICP-AES at Saint Etienne.

Besides these industrial projects, academic studies have been carried out by research students:

Mohamed NASRAOUI presented a thesis entitled 'Le gisement de Niobium de Lueshe (Nord-Est Zaïre) : évolutions géochimique et minéralogique d'un complexe carbonatitique en contexte hydrothermal et supergène' (to be available in 1997);

Mijung LEE is currently working on the petrochemistry of the Sokli complex; she will present her thesis before end 2001.

_We participate to the Project INTAS-97-0722,
entitled "Mineralogy and genesis of rare metal, noble metal, PGE and REE mineralisation in carbonatite complexes, and its petrogenetic significance"

_The Project involve the Teams from the following Institutions:

• From EC Countries:
• The Natural History Museum, Department of Mineralogy, London, United Kingdom  (responsible Dr C.T. Williams, Project Coordinator)
• Institut für Mineralogie un Lagerstattenlehre, Faculty of Geology, Department of Geochemistry, Aachen, Germany (responsible Prof. U. Kramm)
• Ecole des Mines, Centre SPIN, Département Géochimie, Saint Etienne, France (responsible Dr. J. Moutte)
• From Russia:
• St. Petersburg State University, Faculty of Geology, Department of Mineralogy, St. Petersburg, Russia (responsible Dr A. Zaitsev)
• Mechanobr Research Institute, Regional Mechanobr Analit Centre, Scanning Electron Microskopy Laboratory, St. Petersburg, Russia (responsible Dr. N. Rudashevsky)
• Kola Science Centre of the Russian Academy of Sciences, Geological Institute, Apatity, Russia (responsible Dr G. Ivanyuk)

_Our main Task in this project is to provide bulk chemical analysis  of carbonatites and associated rocks. The objectives are to acquire major and trace element chemical analyses of the rocks hosting the rare element mineralisation, in ultrabasic alkaline carbonatite complexes (Kola), in order to define and model their geochemical characteristics, and compare them with those for carbonatites associated with peralkaline nepheline syenites (Khibina) and miaskitic syenites (Ural Mountains).