In World Class Gold and Silver District, 100% EXMIN
In December 2006, EXMIN acquired rights to approximately 7,500 hectares in the northern extension of the Guanajuato district of Central Mexico, a region with historical production estimated to be 1.0-1.5 billion ounces of silver and 5.0 million ounces of gold. Mining and exploration in the district has recommenced in recent years by Canadian junior mining companies such as Great Panther Resources and Gammon Lake Resources. The land package acquired by EXMIN covers a major portion of a series of vein systems that measure 12 kms along strike by 3 kms, and contains several past producing mines. The concessions lie in the state of Jalisco near the boundary with the state of Guanajuato.
A major international mining company explored part of the district in 2004 and 2005. The owner of the concessions has provided information from this exploration program to EXMIN. Detailed geologic maps were completed and more than 600 surface samples were taken. Twelve diamond drill holes totaling 3570 meters were also completed. This exploration program tested the veins at depth from easily accessible areas, but generally did not test the areas of past mining and the immediate extensions along strike.
There are several types of mineralization known within the boundaries of the Horcon land package. The current focus of exploration is a system of epithermal veins that generally strike northwest and appear to be the northern extension of the veins exposed at Guanajuato. Approximately 25 linear kilometers of veins have been delineated within the optioned land package. The veins are dominantly hosted by a granitic pluton and a sequence of Mesozoic volcano sedimentary rocks that form the basement in the region. Five major vein systems transect the district and have been exploited in several places by old mines and prospects. Work commenced in the vicinity of the Horcon mine where high grade polymetallic veins are exposed at the surface and in underground workings, and is extending to other areas of the project.
The main presently accessible working at the Horcon mine is the Horcon adit, which cuts across several of the veins and also intersects several stopes that exploited the low angle veins. Sample data from the walls of old workings and from pillars, provided to EXMIN by the concession owner, yielded up to 67 grams per metric ton (g/t) gold along with important concentrations of silver, lead and zinc from veins that vary from 10 centimetres to 2 metres in width. EXMIN geologists also collected samples to verify the values. Only limited modern exploration, consisting of geologic mapping and sampling, has occurred in this area.
Weighted averages of historical samples, Horcon mine
|
Specific Vein
(Number of samples) |
Average
Width |
Gold
|
Silver
|
Copper
|
Lead
|
Zinc*
|
|
|
cm |
g/t |
g/t |
% |
% |
% |
|
Raton Veins (12) |
63 |
|
4.8 |
|
79 |
|
0.2 |
2.1 |
3.1 |
|
Unnamed Vein 1 (4) |
59 |
|
3.0 |
|
27 |
|
0.1 |
1.6 |
1.9 |
|
San Guillermo Vein (21) |
44 |
|
15.7 |
|
85 |
|
0.3 |
2.9 |
3.9 |
|
La Galvana Vein (9) |
41 |
|
17.9 |
|
134 |
|
0.1 |
3.5 |
1.5 |
|
Diamantillo Vein (5) |
141 |
|
1.5 |
|
20 |
|
0.1 |
0.8 |
0.8 |
| |
|
|
|
|
|
|
|
|
|
|
*Samples from all of the veins except for Diamantillo contained assays with >5% Zn that were averaged using 5%.
A few drill holes were completed at Horcon in 2005, but only tested the veins at depth below the old workings, and no holes have been drilled in the main area of past mining activity or directly along strike. EXMIN completed a preliminary core drilling program at the Horcon mine in mid 2007. The results confirmed the potential for high grade epithermal vein mineralization on the Diamantillo vein as indicated by the assay results. Further drilling using surface and underground core rigs is planned to be able to define a resource at the Horcon mine.
Samples from the Diamantillo vein
|
Sample |
Width |
Au |
Ag |
Cu |
Pb |
Zn |
|
|
metres |
g/t |
g/t |
% |
% |
% |
|
Underground workings* |
|
|
|
|
|
|
|
25643 |
0.75 |
0.62 |
2.0 |
0.01 |
0.29 |
0.20 |
|
25644 |
1.20 |
1.28 |
25.0 |
0.09 |
1.07 |
0.37 |
|
25697 |
2.00 |
2.78 |
20.0 |
0.09 |
0.67 |
0.93 |
|
25698 |
1.30 |
2.43 |
42.0 |
0.10 |
2.29 |
2.28 |
|
25699 |
1.80 |
0.09 |
7.0 |
0.02 |
0.07 |
0.08 |
|
5301-5302 |
2.35 |
2.13 |
140.8 |
0.14 |
0.91 |
1.30 |
|
5303 |
1.60 |
3.16 |
69.6 |
0.31 |
1.23 |
1.82 |
|
5304-5305 |
2.45 |
1.08 |
120.4 |
0.04 |
0.30 |
0.42 |
|
5306-5307 |
2.10 |
2.18 |
54.2 |
0.29 |
1.15 |
1.37 |
|
5308 |
1.65 |
2.27 |
36.8 |
0.11 |
1.53 |
2.12 |
|
5309-5310 |
1.95 |
1.12 |
30.1 |
0.07 |
1.10 |
0.51 |
|
5311 |
1.80 |
3.13 |
257.0 |
0.08 |
0.31 |
0.28 |
|
5312 |
1.20 |
0.89 |
15.8 |
0.06 |
0.92 |
0.60 |
|
5313-5315 |
2.10 |
2.77 |
178.0 |
0.61 |
1.49 |
1.89 |
|
5316 |
1.50 |
0.76 |
22.7 |
0.14 |
1.77 |
1.82 |
|
Average |
1.72 |
1.86 |
77.6 |
0.15 |
0.98 |
1.08 |
|
|
|
|
|
|
|
|
|
Drill Holes |
|
|
|
|
|
|
|
HOR-07-1 |
3.60 |
2.88 |
60.9 |
0.22 |
2.76 |
2.18 |
|
Including |
0.30 |
18.20 |
124.0 |
0.67 |
13.00 |
8.17 |
|
|
|
|
|
|
|
|
|
HOR-07-4 |
1.70 |
0.48 |
86.4 |
0.20 |
0.69 |
0.78 |
|
|
0.60 |
0.71 |
23.9 |
0.19 |
1.08 |
0.54 |
* Samples 25643 to 25699 are from the database of a previous major international exploration company provided by the mine owner. All other samples were taken by EXMIN.
In addition to the vein mineralization, skarn and replacement mineralization are present where the intrusive rocks are in contact with limestone. Also, volcanogenic massive sulfide lenses have been discovered in the Mesozoic volcano sedimentary rocks; these deposits were previously explored by Noranda. Both types of mineralization are known to contain economic deposits elsewhere in the region and will be evaluated by EXMIN geologists in early 2008.
