NI 43-101 Technical report, Surface diamond drilling ... - Iamgold

R a r e E a r t h E l e m e n t E x p l o r a t i o n P r o g r a m M a r c h - 2 0 1 3
W i n t e r - S u m m e r 2 0 1 2 P a g e | 17
This carbonatite is known as the host of two individual deposits:
• Niobium deposit in the south part of the carbonatite, which constitute the principal
Niobec mine;
• REE Zone mineralized in lanthanides elements, located in the central part of the
carbonatite.
9.2.1 The St-Honoré alkaline complex
9.2.1.1 Geological Highlights
The first complete geological map, using the different geophysical surveys and drill holes
data realized between 1967 and 1975, has been produced by Soquem geologists (Gauthier.A
and al.) in 1978. This map, based on petrographic and geochemical studies which allow the
definition of the different carbonatite terms (Fortin, 1977), has been actualized and
reinterpreted in 1986 by Niobec Mine geology staff using the additional drill holes data
realized by Soquem in 1985.
The geological compilation map of Figure 5 is the result of a synthesis of these entire maps
and the drill holes data since 1967.
The Alkaline complex is composed by a central carbonatite core, surrounded by mainly an
alkaline syenite, a feldspathoid bearing syenite and syenitic foidites (Ijolites and urtites)
(Fortin, 1977; Figure 5). The contact of this complex with the country rocks is marked by a
phlogopite calcitite in the northern part and in the southern part by the presence of a
cancrinite bearing syenite (Dénommé, 1986).
A chronology has been established for this Alkaline complex as follow from older to younger
(Fortin, 1977):
Ijolite - Urtite - Foidites syenite – Feldspathoid syenite – Alkaline syenite – Lamprophyre -
Carbonatite
Following a petrographic and geochemical study (Fortin, 1977) of different drill holes cores
realized in the carbonatite by Soquem (Gagnon and al., 1973), different carbonatite units with
different geochemical characteristics have been established. Four Sovites (Calcitites) types
and three Rauhaugites (dolomitites) types have been recognized and constitute the different
units of the carbonatite core. These units consist of a series of crescent shape lenses of
carbonatite with younger compositions progressively inwards from calcitite through
dolomitite to ferro-carbonatite (Fortin, 1997). This evolution is attested by the numerous
xenolithes of the alkali syenite rocks in the carbonate at the scale complex and at a smaller
scale between the different carbonates facies themselves.
3400, chemin du Columbium, St-Honoré-de-Chicoutimi, QC G0V 1L0 Canada – tel. : 418 673-4694 Fax : 418 673-3179
E-mail : info.niobec@iamgold.com www.niobec.com