In February 1999, Hecla drilled 25 reverse circulation ("RC") drillholes totaling 1,610m. Most of the holes were drilled to a depth of 50m, with a few holes to more than a 100m depth. The RC Samples were collected at 2m intervals and analyzed for gold and with some also analyzed for copper. The average gold content of all samples was 306 ppb Au with the best single value over the 2m interval at 3,388 ppb Au. The best 2m interval analyzed for Cu was 3,188 ppm. Of the total 805 RC samples collected, all but 37 samples contained measurable gold values with 152 of the samples containing more than 500 ppb. Although Hecla estimated a potential resource of 12.85 million tonnes of 0,50 g/t Au and 211 ppm Cu with an in-situ mineral inventory of 206,998 oz Au, the gold grades were at that time considered uneconomic. The historical mineral resource does not conform to NI 43-101 standards and the reader is cautioned that this is historical reported mineral resource and cannot be relied upon but the author believes it relevant to be included herein.
HECLA "RC" DRILL RESULTS
|
Hole ID |
From |
To |
Au |
Cu |
Interval |
Ratio |
|
99MHM1 |
0 |
10 |
1.1 |
0.02 |
10 |
.02 |
|
99MHM1 |
30 |
40 |
0.9 |
0.02 |
10 |
.02 |
|
99MHM3 |
0 |
40 |
0.9 |
0.02 |
40 |
.02 |
|
99MHM9 |
28 |
44 |
1.2 |
0.00 |
16 |
0 |
|
99MHM10 |
2 |
20 |
0.9 |
0.02 |
18 |
.02 |
|
99MHM11 |
0 |
12 |
1.1 |
0.01 |
12 |
.01 |
|
99MHM14 |
4 |
30 |
0.7 |
0.04 |
26 |
.02 |
|
99MHM16 |
30 |
42 |
0.6 |
0.04 |
12 |
.06 |
|
99MHM23 |
0 |
24 |
1.1 |
0.02 |
24 |
.07 |
|
99MHM23 |
46 |
58 |
0.9 |
0.03 |
12 |
.03 |
|
Average |
|
|
1.0 |
0.02 |
|
0.02 |
The above table illustrates the gold and copper values of intervals of more than 10m at a 0.5 g/t Au cutoff, allowing up to 2m intervals of 0.3 g/t Au.
The Hecla RC drillhole sample data shows a very
low %Cu to Au ppm ratio, ratios almost identical to the porphyry gold
(copper) deposits of the Maricunga Belt in Chile (Muntean and Einaudi,
2000). Porphyry gold (copper) deposits are associated with subvolcanic
andesitic to dacitic intrusions emplaced into coeval volcanic rocks and form
at shallower crustal depths than porphyry copper deposits; near the
epithermal transition zone. Porphyry gold ( copper) deposits are
believed to be a subset of IOCG type deposits (iron oxide-copper gold;
Sillitoe, 2003). The drillhole and channel sampling by Hecla suggest
that La Calerita could contain a porphyry gold (copper) deposit.
Hecla Drill Results
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