White Rock’s project portfolio includes exposure to high-grade zinc and silver through its wholly-owned Red Mountain Project in Alaska.
The Red Mountain Project is located in central Alaska, 100km south of Fairbanks in the Bonnifield Mining District. The tenement package comprises 760 mining claims over a total area of 475km².
Red Mountain Project Location.
Minerals Resources and Historic Exploration
The Red Mountain Project contains polymetallic VMS mineralisation rich in zinc, silver and lead, as well as gold and copper. Previous exploration has resulted in the discovery of two deposits: Dry Creek and West Tundra Flats.
White Rock used historical drilling to determine a maiden Mineral Resource estimate for the Dry Creek and West Tundra Flats deposits (ASX Announcement 26th April 2017). The Inferred Mineral Resource contains an impressive base metal and precious metal content with 678,000t zinc (Zn), 286,000t lead (Pb), 53.5 million ounces silver (Ag) and 352,000 ounces gold (Au).
Above: Red Mountain April 2017 Inferred Mineral Resource Estimate prepared and reported in accordance with the JORC Code (2012)
Table 2: Red Mountain April 2017 Inferred Mineral Resource Estimate at a 3% Zn cut-off (contained within Table 1, not additional) prepared and reported in accordance with the JORC Code (2012)
Zinc equivalent grades are estimated using long-term broker consensus estimates compiled by RFC Ambrian as at 20 March 2017, adjusted for recoveries derived from historical metallurgical testing work and calculated with the formula:
1ZnEq =100 x [(Zn% x 2,206.7 x 0.9) + (Pb% x 1,922 x 0.75) + (Cu% x 6274 x 0.70) + (Ag g/t x (19.68/31.1035) x 0.70) + (Au g/t x (1,227/31.1035) x 0.80)] / (2,206.7 x 0.9).
White Rock is of the opinion that all elements included in the metal equivalent calculation have reasonable potential to be recovered and sold.
Previous drilling highlights (ASX Announcement 15 February 2016) include:
4.6m @ 23.5% Zn, 531g/t Ag, 8.5% Pb, 1.5g/t Au & 1.0% Cu from 6.1m
5.5m @ 25.9% Zn, 346g/t Ag, 11.7% Pb, 2.5g/t Au & 0.9% Cu from 69.5m
7.1m @ 15.1% Zn, 334g/t Ag, 6.8% Pb, 0.9g/t Au & 0.3% Cu from39.1m
West Tundra Flats
1.3m @ 21.0% Zn, 796g/t Ag, 9.2% Pb, 10.2g/t Au & 0.6% Cu from 58.6m
3.0m @ 7.3% Zn, 796g/t Ag, 4.3% Pb, 1.1g/t Au & 0.2% Cu from160.9m
1.7m @ 11.4% Zn, 372g/t Ag, 6.0% Pb, 1.7g/t Au & 0.2% Cu from 104.3m
Mineralisation occurs from surface and is open along strike and down-dip.
Good preliminary metallurgical recoveries of >90% Zn, >75% Pb, >80% Au, >70% Ag and >70% Cu.
Geological Setting and Exploration Opportunity
VMS deposits typically occur in clusters (“VMS camps”). Typically, deposits are evenly spaced within a camp. Within almost all camps, deposit sizes are log normally distributed. In mature camps this means one “giant” (> 40Mt of ore, 1.8Mt of total base metal: upper 10% of all VMS deposits), two large (>10Mt ore, 550,000t of base metals: upper 25% of all deposits) and 3-8 small (<3.3Mt ore, 150,000t of base metal, 50% of all deposits) deposits /occurrences.
Typical VMS camps consist of 4-8 deposits, each spaced about 4km to 6km apart. The known deposits at Dry Creek and West Tundra Flats provide valuable information with which to vector and target additional new deposits within the Red Mountain camp.
Interpretation of the geologic setting indicates conditions that enhance the prospectivity for gold-rich mineralisation within the VMS system at Red Mountain. Gold mineralisation is usually found at the top of VMS base metal deposits or adjacent in the overlying sediments.
Gold-bearing host rocks are commonly not enriched in base metals and consequently often missed during early exploration sampling. This provides an exciting opportunity for potential further discoveries at Red Mountain.
White Rock sees significant discovery potential, given the lack of modern day exploration at Red Mountain. This is further enhanced by the very nature of VMS clustering in camps, and the potentially large areas over which these can occur.