Regionally, the area is underlain by equigranular biotite- and hornblendebearing granitoids and leucocratic aplite dykes of inferred Early Cretaceous age, comprising the Nisling Range batholith. In general, the Nisling Range batholith varies from non-magnetic granitic compositions in the west to magnetic dioritic compositions further east. Porphyritic dykes are locally noted nearby cutting the Nisling Range granitoids; these dykes may be Cretaceous in age, or may correspond with nearby Early Tertiary intrusive ages documented by Murphy (2011).

The Nisling Range batholith intrudes Snowcap and Finlayson assemblage rocks of the Yukon Tanana terrane (YTT). In the area, the Snowcap assemblage is dominated by siliceous meta-clastic rocks (quartz-biotite and quartz-muscovite schists). Subordinate marble and carbonaceous meta-clastic rocks likely correlate with the Finlayson assemblage.

The Hailstorm zone is marked by large sub-angular to sub-rounded granitic boulders along a rounded NW-SE trending ridge, approximately 1.5km from the northern edge of the Nisling Range batholith. Host rocks comprise a black and white biotite-hornblende-granodiorite with up to 10% sheeted quartz veining. The granodiorite is predominantly unaltered, with only localized zones of weak argillic alteration of plagioclase and chlorite after biotite and hornblende. Chlorite-clay veinlets are also present in some zones, with associated iron-carbonate (ankerite?) and trace pyrite. Mineralization is hosted within the sheeted quartz veins, and includes pyrite, chalcopyrite plus malachite, arsenopyrite, molybdenite and rare visible gold. Disseminated molybdenite and pyrite are also observed in some samples. Overall sulphide concentrations are low (<0.1%), but locally reach 1- 2% in select samples. Quartz veins are on average 1-4mm wide, with an average spacing of 10- 20cm. Locally wider (5-15cm) smoky grey to milky white quartz veins were also observed in the granodiorite, but no sulphides were observed in hand sample of these veins.

Prospecting in 2012 returned values of 1.7 g/t Au, however diamond drilling confirmed only weak to moderate sheeted quartz and quartz-chlorite veining.
(AR 09662), (AR 96330)