The Blachford Property consists of four mineral claims, covering approximately 7130 acres of land in south-eastern portion of the Northwest Territories. It is located about 95 km southeast of Yellowknife, and is contiguous with the Nechalacho Project, of Avalon Rare Metals Inc, which is known for its heavy rare earth element (HREE) potential.
The Blachford Property is located within the Precambrian Shield, and encompasses part of the Aphebian alkalic, plutonic Blachford Lake Complex (BLC). The BLC is an igneous domain, in which successive intrusive phases range from older mafic bodies, through intermediate intrusions, to alkali-rich and increasingly felsic plutons. The property is situated near the centre of the BLC within the youngest Grace Lake Granite domain. It is south of Blachford Lake and north of Thor Lake. The Grace Lake Granite appears to represent a more felsic penecontemporaneous equivalent of the Thor Lake Syenite.
Nepheline syenite outcrops in the central sector of the BLC, in the environs of Thor Lake, contain rare earth element (REE)-rich mineralization. What is now known as the Nechalacho REE-Zr-Nb-Ta Deposit (formerly the Thor Lake Deposit) is hosted by a subhorizontal, layered nepheline syenite body situated below the uppermost Thor Lake Syenite-Grace Lake Granite lithologies of the BLC.
In 2010, the hydrothermally altered REE-Zr-Nb-Ta-bearing nepheline syenite intrusion was shown not to be confined to the environs of Thor Lake. It is now thought that this REE-rich layered intrusion, the Nechalacho nepheline syenite, is a larger sill-like entity with lateral extensions to the north around Cressy Lake and perhaps even beyond that point.
Two sites (Localities 1 and 2) were visited based upon aeromagnetic anomalies identified by the GSC (1988) and geological investigations were performed. The Grace Lake Granite outcrops examined had crosscutting fractures and narrow veins (<2m) that often weathered to a chocolate-brown colour and often proved to be radioactive (scintillometer readings of up to 650 cpm). The occasional medium-grained aplitic lithologies encountered during cursory ground surveys were also slightly radioactive. Many of the brown weathering fractures and narrow veins were clearly enriched in U±Th and possibly originally contained sulphides. Six samples of these veins and their altered wall rocks were collected, together with one background sample of pristine, unaltered Grace Lake Granite.
The altered Grace Lake Granite and veins contain significant introduced contents of Zr, Nb, Ta, Th, and U with lesser but significant quantities of light rare earth elements (LREE) La, Ce, Pr, Nd, Sm, and heavy rare earth elements (HREE) Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu, and Y. Total rare earth element oxides (TREO) within the veins show a maximum of 0.126%; heavy rare earth element oxides (HREO) are 21.99% of the TREO in this sample. This ratio is similar to the HREO distribution recorded by Avalon for the Basal HREE zone of the Nechalacho Deposit below Thor Lake, where average HREO content is about 20% of the TREO content (Avalon Rare Metals, 2011). Percentage-level concentrations of Nb2O5 in three samples are highly significant. The contents (up to 0.455%) compare with average concentrations of Nb2O5 in the Nechalacho Syenite REE-Zr-Nb-Ta-(U-Th) Deposit around Thor Lake to the southeast.
Subsequent structural interpretation of satellite images of the Blachford Property revealed a series of topographic lineaments that could have resulted from uplift or roof collapse of an underlying younger intrusive body. These lineaments are parallel to NW-trending anisotropic features visible on a preexisting aeromagnetic data map (magnetic highs) and on an airborne radiometric survey (Th equivalent). This has led the author of the NI 43-101 report to hypothesize that the REE-Zr-Nb-Ta-bearing Nechalacho nepheline syenite intrusion could extend northwestward from Thor Lake at depth to the Blachford Property. The newly discovered Zr-Nb-Ta-Th-U-REE bearing veins may be caused by upward venting of hydrothermal fluids from an underlying REE-Zr-Nb-Ta-(U-Th)-enriched intrusion.
The Blachford Property is considered under-explored for syenite-hosted REE-Zr-Nb-Ta deposits and is of sufficient merit to warrant further exploration.
The technical content within this webpage was been reviewed and approved by Dr. Roger D. Morton, P Geol., who is the Qualified Person for purposes of NI 43-101.
