In the lac de la Haute Sauvage area, approximately 30 km to the south of the Company's claim blocks, but within the same lithologies, van der Leeden (1994) noted that pegmatite containing dark gray quartz and / or hematite were more radioactive than the enclosing host rocks. It was also noted that shear zones cutting porphyritic granite and rocks containing fluorite were noticeably radioactive.
Geological mapping in the lac Mina area approximately 50 km south of the Company's properties discovered a uranium showing, described as a quartz rich layer 30 cm thick within paragneiss, and traceable for 100 m along strike. The radioactive mineral is identified as very fine grained colloform pitchblende, and two assays returned values of 0.39 % U and 0.85 % U accompanied by anomalous quantities of lead, thorium and yttrium (Bourque, 1988).
The geology of the area indicates that the uranium deposit model with relevance to the Company's properties is the "intrusive type" associated with intrusive rocks including alaskite, granite, pegmatite and monzonites. The major primary ore mineral is uraninite (UO2) or pitchblende (U2O5.UO3), though a range of other uranium minerals is found in particular deposits. These include carnotite (uranium potassium vanadate), the davidite-brannerite-absite type of uranium titanates, and the euxenite-fergusonite-samarskite group (niobates of uranium and rare earths) (Lambert, 1996).
Major world deposits include Rossing (Namibia), Ilimaussaq (Greenland), Palabora (South Africa), Radium Hill (Australia) and Crocker Well (Australia) are examples of "intrusive type" deposits.
Lake sediment sampling is a useful exploration tool regardless of the deposit type. Results are interpreted in light of several variables. The two most important are: (1) differences in type and composition of the source material from which the lake sediments are derived, and (2) differences in the chemical and mechanical dispersion processes that move the material from source to sampling site. Other factors affecting interpretation include scavenging by organic material, scavenging by hydrous oxides iron and manganese oxides and contamination.
There are three primary sources from which elements in lake sediments are derived: bedrock, glacial deposits and mineralization. The most important source is bedrock, as most elements are preferentially concentrated in certain rock types because of igneous or sedimentary processes. Numerous studies have shown that the geochemical distribution patterns of elements in lake sediments are largely related to and reflect the variations in the chemical composition of the underlying bedrock (Garrett et al, 1990). Although the size of a given mineral occurrence is small relative to the total area of a catchment basin draining into a lake, it can exert a significant influence on the sediment composition. Economically interesting mineralization contains element concentrations several orders of magnitude greater than in the surrounding bedrock, resulting in an anomalous value.
Most areas in which lake sediment surveys are conducted are covered to a greater or lesser extent by glacial deposits, of which till is the most common. These deposits are generally composed of material that has been transported only a relatively short distance (Shilts, 1976) and have a chemical composition similar to the underlying bedrock.
Geophysical methods used in the search for radioactive mineralization use airborne gamma-ray spectrometers for surveys, and gamma-ray spectrometers / scintillometers for ground surveys. Airborne magnetic surveys are ancillary techniques that can provide information on lithologies and structures which may be important in follow-up exploration programs.
There does not appear to be a sympathetic relationship between positive magnetic features and anomalous uranium values in lake sediment samples. The magnetic fabric trends generally north-northwest, faults trend generally north and the distribution of anomalous lake sediment samples appears to spatially coincide with felsic intrusions in the bedrock.
