Following rock sampling, "scout" drilling of skarn was conducted using a hand portable, 2-cycle gasoline powered drill manufactured in Canada known in the mineral exploration industry as a "Winkie" drill. Highlights of drilling include the following intervals. All holes were drilled at a high angle to relict bedding surfaces which are known to define the boundary of mineralized horizons (referred to as "mantos") and are believed to be close to true widths.
| Hole | UTM | Az/dip | Depth m | Interval m | Ag gpt | Cu % | Pb % | Zn % | Comments |
|---|---|---|---|---|---|---|---|---|---|
| RA-1 | 4476N 6160E | 030/-60 | 0-4.88 | 4.88 | 57 | 0.29 | 6.05 | Entire hole mineralized | |
includes |
0-0.9 | 0.9 | 131 | 0.058 | 1.03 | 10.9 | |||
| and | 4.0-4.88 | 0.88 | 14 | 0.03 | 7.56 | Hole ends in mineralization | |||
| BR-1 | 5744N 8434E | 200/-70 | 3.81-8.86 | 5.05 | 461 | 9.22 | 8.5 | ||
| includes | 6.42-7.64 | 1.21 | 1235 | 0.11 | 26.24 | 11.5 | |||
| and | 7.64-8.86 | 1.22 | 162 | 3.08 | 17.9 | ||||
| BR-3 | 5660N 8353E | 120/-70 | 9.3-11.59 | 2.29 | 780 | 17.9 | 10.9 | ||
| 11.59-14.18 | 2.59 | 7 | 0.2 | 6.15 | Hole ends in mineralization | ||||
| BR-5 | 5803N 8586E | 135/-70 | 0-3.66 | 3.66 | 73 | 1.3 | 1.57 | ||
| BR-6 | 5431N 8541E | 120/-70 | 0-1.53 | 1.53 | 65 | 0.18 | 0.76 | 11.58 | |
| 9.61-12.2 | 2.59 | 49 | 0.46 | 1.32 | Hole ends in mineralization | ||||
| BR-8 | 5406N 8564E | 150/-57 | 0-9.61 | 9.61 | 24 | 1.6 | Entire hole mineralized |
Note: UTM is the Universal Transverse Mercator coordinates of the drill holes, Az is the hole azimuth, dip is the deviation of the drill hole from horizontal. Ag is silver concentation in grams per metric tonne, Zn, Cu and Pb are weight percent.
This "scout drilling" program demonstrates the presence of widespread disseminated Zn mineralization between 0.3 and 2% Zn, plus high grade "manto" zones containing up to a maximum of 1235 grams per tonne silver (~39 ounces per tonne silver), 26% lead, 17.9% zinc. This "manto" zone typically contains approximately 5-10% Zn, 5-10% Pb, 200-500 gpt Ag over significant intervals distributed over a large area. A zone of mineralization containing 1.36% Cu, 1.57% Zn, 73 gpt Ag was also drilled. Geological mapping shows that these skarns continue for at least 1 kilometer length, 300 meters width and a minimum thickness of 50 meters. It is likely that this skarn is larger than this and continues underneath pediment cover.
A differentiated suite of intrusives ranging from diorite porphyry through granodiorite porphyry to quartz porphyry is associated with skarn development and is mineralized. Intrusives adjacent to the La Bronca skarn are predominantly granodiorite porphyry with stockwork quartz veining, iron and copper oxide minerals and sericitic alteration. Cross cutting the granodiorite stock are one or more 20 meter wide porphyryitic microgranular granodiorite dikes carrying copper mineralization with sericite alteration locally changing to epidote-propylitic alteration. Chrysocolla and neotocite occur within the dike over approximately 200m of strike length and extending to the west beneath pediment cover.