An ongoing drill program at the Navidad polymetallic property in Argentina has returned the highest silver grades yet for IMA Exploration (IMR-V).
To date, IMA has completed just over half of a planned 8,500-metre program, with hole 27 now under way. The first-phase program is following up the discovery of surface silver-copper-lead-zinc in early 2003.
The latest batch of results come from holes 12-14. Results for the remainder are pending.
Hole 14, collared 160 metres northwest of holes 3-5, at the Navidad Hill prospect, cut 115.1 metres grading 453.6 grams silver per tonne, 0.08% copper, 5.26% lead and 0.5% zinc. The mineralized interval included 18 metres at a whopping 1,421.2 grams silver (41.5 oz. per ton), 0.42% copper, 5.24% lead and 1.69% zinc.
The intersection includes sulphide-rich mudstones and underlying volcanic breccias known as Galena Matrix Breccia. The presence of copper sulphides suggests that the contact is the subsurface equivalent of copper-bearing carapace (clast supported) breccias outcropping at surface.
IMA believes the interval reflects a feeder zone, or the surrounding environment, of replacement mineralization in the volcanic stratigraphy. Capping this type of mineralization is stratiform-type mineralization at the base of the overlying mudstone unit.
Results from hole 12 lend further support to the model. It cut through 9 metres of mineralized mudstone grading 41.6 grams silver, 8.01% lead and 2.56% zinc, followed by 7.7 metres of volcanic breccias running 70.8 grams silver, 9.6% lead and 0.54% zinc.
The units dip gently to the west.
Meanwhile, hole 13 tested the Galena Hill showing, where mineralization is associated with the margin of a felsic flow dome. The hole cut 44.7 metres of breccia grading 223.4 grams silver, 0.16% copper and 0.56% lead.
Although texturally distinct from Navidad Hill, Galena Hill also is characterized by low concentrations of sulphide with high silver tenors. Unfortunately, the paucity of sulphides makes the prospect a poor candidate for induced polarization surveys now under way.
Both Navidad Hill and Galena Hill are close to surface and hence considered prospective bulk-tonnage deposits.