The Mill carbonatite showing is located approximately 1600 metres due north of the Verity occurrence (083D 005). The Mill is easily reached by logging roads which cross the North Thompson River and intersect highway 5 at Lempriere Station, 40 kilometres north of Blue River.

Carbonatite consisting of sovite and lesser beforsite occurs as sills within quartz-hornblende-mica schist of the Semipelite Amphibolite division of the Hadrynian Horsethief Creek Group. For a comprehensive description of the regional geologic setting of the Mill showing refer to the Verity carbonatite (083D 005).

The Mill showing consists primarily of two major sovite units similar to the lower two sovite units of the Verity. This zone can be traced discontinuously in a north-south direction for up to 300 metres. The gneiss and carbonatite have been folded into a tight fold and carbonatite appears to be concordant with the gneiss foliation. To the west of the fold axis the carbonatite dips steeply to the west.

A banded texture caused by layering of the accessory minerals apatite, amphibole, olivine, magnetite, biotite, pyrite, pyrrhotite, pyrochlore, columbite, and zircon is common in the sovite unit and less developed in the beforsite unit.

Anomalous values of niobium occur in the lower half of the lower sovite unit. Values up to 0.42 per cent Nb2O5 over 1.5 metres occur for a strike length of 100 metres (Assessment Report 10274). Drill intersections from holes M-1 and M-2 assayed up to 0.24 per cent Nb2O5, 0.089 per cent tantalum, and 4.62 per cent P2O5 (Assessment Report 9566). A drill hole intersection between 120 to 133 feet in hole M-2 assayed 0.24 per cent Nb2O5, 0.011 per cent tantalum, and 3.38 per cent P2O5 (Assessment Report 9566).