White Rock has chosen to focus exploration on the Bonnifield East area where the two most significant deposits of Dry Creek and West Tundra Flats are located on opposite limbs of a regional syncline (Figure 6). The syncline controls the distribution of the prospective VMS horizon with the upper metasiliciclastic rocks of the Totalanika Schist forming the hangingwall to VMS mineralisation throughout the district. The prospective footwall sequence dips steeply to the north along the southern limb (where the Dry Creek deposit is located) and shallow to the south along the northern limb (where the West Tundra Flats deposit is located).
White Rock has compiled all available data sources of the Bonnifield East district, for use in defining WMS targets through the power of modern vector analysis and 3D processing. Targeting has focused on specific extensions to the known mineralisation as well as district wide targets that could represent additional zinc – silver deposits in the Red Mountain VMS camp
Dr Jim Franklin, a recognised global VMS expert, completed an assessment of compiled surface geochemical data. The study aimed to use modern vector analysis to identify new exploration targets from old data. Dr Franklin was able to use the known deposits at Dry Creek and West Tundra Flats to calibrate his assessment of the regional data. The resulting assessment prioritises the Dry Creek West, ReRun, West Tundra Flats, Smog and Glacier target areas as highly prospective for additional VMS deposits (Figure 6). Observations based on the zonation of geochemical alteration and detailed geological mapping provided by the DGGS suggest that each target area shows extensive lateral and vertical footwall alteration, and the potential for a number of mineralised horizons and indicators for proximal base metal (zinc-lead) and precious metal (gold-silver) mineralisation.
Condor Consulting, Inc., recognised experts in the field of airborne electromagnetics (“EM”), completed a detailed interpretation of the EM and magnetics survey flown by the Alaskan Division of Geological and Geophysical Surveys (“DGGS”) in 2007. Condor was able to use the known deposits at Dry Creek and West Tundra Flats to calibrate the assessment of the EM and magnetics data. A number of high priority conductors were identified as having the potential of being caused by massive sulphide mineralisation (Figure 7). The highest priority conductors are located within the identified geochemical target areas, some of which are coincident with strong base metal and precious metal anomalies from historic sampling (Conductors 1 to 30).
Subsequently White Rock expanded the Red Mountain tenement package to 143km², which covers the best geochemical targets along both limbs of the syncline (Figure 6), including a significant area down dip of the exposed prospective VMS horizon. The expanded tenement position provides White Rock with a significant land package containing numerous targets with the potential for additional deposits that could transform the Red Mountain project into Alaska’s next development project.
Figure 6: Red Mountain project tenement outline on the DGGS geology map (sourced from the DGGS Preliminary Interpretative Report 2016-3 by Freeman et al., 2016) with locations for the Dry Creek and West Tundra Flats VMS deposits, and the geochemical target areas.
Figure 7: Red Mountain high priority conductors (pink) on a conductivity depth slice at 40m below surface from the 1D inversion of airborne electromagnetics. Locations for the Dry Creek and West Tundra Flats VMS deposits, and target areas (ReRun, Dry Creek West, Rod, WTF, Smog South, Smog North, Glacier East, Glacier West and Sheep Rogers) are defined by geochemical alteration (in green boxes), and the corridor of conductors along the northeast trend from Dry Creek to West Tundra Flats (dashed yellow line).
Preliminary analysis of the geologic setting of the Bonnifield District and the Dry Creek and West Tundra Flats deposits indicates that the Red Mountain Project has the volcanic, geochemical, alteration and sulphide assemblage characteristics of a very shallow water, boiling hydrothermal system. Such conditions enhance the prospectivity for gold-rich systems since gold is transformed as a bisulphide complex that has inverse solubility and is precipitated only on oxidation of the fluid, usually at the top of massive sulphide deposits or in the immediate hangingwall sediments. Since gold behaves differently to the base metals the gold bearing host rocks are not necessarily enriched in base metals and consequently are often missed during sampling. The gold bearing host rocks are not enriched in base metals and consequently are often missed during sampling.
On the basis of the above the company is moving forward planning a range of follow-up exploration work that will lead to future drill testing. The focus of these programs is to discover:
- Gold-rich deposits previously not sampled for or targeted.
- A large (10Mt) deposit rich in zinc, lead and silver.
- Additional small deposits.
- Extensions to known mineralisation.
White Rock notes that Alaska is ranked sixth (6th) on the Investment Attractiveness Index released by the Fraser Institute Annual Survey of Mining Companies 2015 out of 109 jurisdictions. The index is weighted 40% by policy and 60% by mineral potential. This also provides the necessary encouragement to invest in this part of the world.