Summary:
The iron formations of the Kami deposits are of the Lake Superior-type.
Iron formations consist mainly of iron and silica-rich beds; common varieties are taconite, itabirite, banded hematite quartzite, and jaspilite; composed of oxide, silicate and carbonate facies and may also include sulphide facies. Commonly intercalated with other shelf sediments: black.
Mineable deposits are sedimentary beds with cumulative thicknesses typically from 30 m to 150 m and strike lengths of several kilometres. In many deposits, repetition of beds caused by isoclinal folding or thrust faulting has produced widths that are economically mineable. Ore mineral distribution is largely determined by primary sedimentary deposition. Granular and oolitic textures are common.
The oxide iron formation ("OIF") consists mainly of semi-massive bands, or layers, and disseminations of magnetite and/or specular hematite (specularite) in recrystallized chert and interlayered with bands (beds) of chert with iron carbonates and iron silicates. All variations of the magnetite- or hematite-rich layers exist, mostly as a transition between the two endmembers. Other variants exist, generally with minor amount of magnetite and hematite, dominated by chert (lean iron formation), iron silicates, iron carbonates, iron silicates and carbonates, or quartz-rich iron formations. Grunerite is the most common mineral of the silicate iron formations and is often observed at the footwall for the Rose Central ("RC") mineralization. Some sub-members of the OIF contain increased amounts of hematite (specularite) associated with manganese silicates and carbonates.
In the Mills Lake area, approximately 3 km south-southeast of Rose, the iron formation consists of a gently east-northeast dipping tabular main zone with several parallel ancillary zones. The iron formation in the Rose area consists of a series of corrugated steeply plunging, northeast-southwest oriented sub-parallel upright to slightly overturned anticlines and synclines.
The portion of the Property east of the western shore of Mills Lake is dominated by gently dipping (15°-20°E) Denault Formation marble with quartz bands paralleling crude foliation.
The Wabush Basin on the Property contains (from south to north) the South Rose/Elfie Lake deposit, the Rose Central deposit (“RC”) and the Rose North deposit (“RN”). These deposits represent different components of a series of gently plunging NNE-SSW upright to slightly overturned anticlines and synclines with parasitic smaller-scale folding. The Rose syncline appears to be dismembered by thrust faulting parallel to the D1 deformation from the SSE. The lateral extent of the southeast limb is limited, while the NW limb forms the long linear trend shown by the airborne magnetic and gravity anomalies and Rivers’ (1985) maps. This fold system continues NNE from the western end of the Rose North deposit toward Long (Duley) Lake. The Wabush Mine deposit lies across the lake where the structure opens into a broad open syncline truncated by a northerly trending late normal fault just west of Wabush.
The Mills Lake Basin is developed south of the Wabush Basin. It is considered to be a separate basin because the amount and distribution of non-oxide facies iron formation is different from the Wabush Basin package at Rose and Wabush Mine.
Mineralization and Structure
Mineralization of economic interest on the Property is oxide facies iron formation. The oxide iron formation ("OIF") consists mainly of semi-massive bands or layers, and disseminations of magnetite and/or specular hematite (specularite) in recrystallized chert and interlayered with bands (beds) of chert with iron carbonates and iron silicates. Several nomenclatures were used to code rock types depending on its magnetite and/or hematite content, with MIF and HIF as endmembers and MHIF and HMIF as intermediate members. Where magnetite or hematite represents minor component of the rock comprised mainly of chert, the rock is named lean iron formation (“LMIF”, “LHIF”). Where silicate or carbonate becomes more prevalent than magnetite and/or hematite, the rock is named silicate iron formation ("SIF") or carbonaceous iron formation (“CIF”), and/or silicate-carbonate iron formation (“CSIF”) and its variants (“QSIF”, ”QCIF”, “QCSIF” for quartz-rich variants). Mafic dykes (“HBG_GN” and variants) and muscovite and/or biotite schists (“B_MS_SCH”, “MS_SCH”, “MS_B_SCH”) are also observed. Throughout its field investigations, GMS found that logged rock types are often inconsistent from one hole to another. For example, several types of SIF were observed, some of which are similar to HBG_GN or CIF.
SIF consists mainly of amphibole and chert, often associated with carbonate and contains magnetite or specularite in minor amounts. The dominant amphibole on the Kami Property is grunerite. Where carbonate becomes more prevalent, the rock is named silicate- carbonate or carbonate-silicate iron formation. However, in practice, infinite variations exist between the OIF and silicate-carbonate iron formation composition end members. SIF and its variants and lean iron formation are also often interbedded with OIF.
The OIF on the Property is mostly magnetite-rich and some sub-members contain increased amounts of hematite (specularite). Hematite appears to be more prominent in Rose North mineralization than at either Rose Central or Mills Lake, but all zones contain mixtures of magnetite and hematite. At both Rose North and Rose Central and at Mills Lake, a bright pink rhodonite, which is a manganese silicate, is associated with hematite-rich OIF facies. Deeply weathered iron formation in the Rose North deposit also contains concentrations of secondary manganese oxides. There may also be other manganese species present.
Mineralization by Rock Type
Samples logged and coded as magnetite-rich are indicated by assay results to contain more magnetic Fe than samples logged as hematite-rich or carbonate and silicate IF. Samples coded as hematite-rich contain more hematitic Fe. At both Rose and Mills, hematite-rich samples contain higher levels of manganese. This can be observed particularly in the groups coded as HIF and HSIF, respectively Hematite Iron Formation and Hematite-Silicate Iron Formation. Carbonate IF (CIF, QCIF) samples are generally higher in CaO, but some misclassification of QSIF may alter its CaO values. Mafic intrusive rocks (HBG-GN) contain higher levels of TiO2, Al2O3 and Mg than IF. Quartz schists, which generally represent Wishart Formation, are high in SiO2 and Al2O3, as are Menihek Formation samples. Denault Formation samples are high in CaO and MgO as this rock is marble or dolomitic marble. There are, however, some anomalies probably resulting from mis logging. Dolomitic samples can be mis-logged as quartzite. Some intervals or samples logged as mafic dykes (HBG-GN) contain high levels of hematite Fe. Samples or units logged as “Lean” iron formation with a Leading “L” in Alderon’s lithology nomenclature often have assays with significant oxide-iron grade.