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San Martin Mine, Mexico

The San Martin project is located 50 km east of the City of Querétaro in Querétaro State, and about 250km northwest of Mexico City. High grade mineralization was discovered at San Martin in the 18th Century, and is reported to have been mined over a period of 40 years; however, no production records exist. Between 1900 and 1924, an estimated 250,000 tonnes grading 15 g Au/t and 100 g Ag/t was reportedly mined.

Location Map

The San Martin project is located 50 km east of the City of Querétaro in Querétaro State, and about 250km northwest of Mexico City. High grade mineralization was discovered at San Martin in the 18th Century, and is reported to have been mined over a period of 40 years; however, no production records exist. Between 1900 and 1924, an estimated 250,000 tonnes grading 15 g Au/t and 100 g Ag/t was reportedly mined.

The San Martin Wedge

The "San Martin wedge" is located at the extreme northeast end of the San Martin portion of the mine. In this location the principle Northeast trending breccia zone was followed along a north northwest trend. Examination by Starcore subsequent to the acquisition indicates that this change in orientation is due to mineralization being dragged along a northerly trending fault with a westerly dip. The result of this is that the area below and northeast of this mineralized fault has seen little exploration between it and the main 28 zone limiting fault. The area between these two faults represents a good target to locate the unexploited Northeast breccia zones in the upper levels where grades were higher than we have in the lower levels. Work to date resulted in the development of a small fault controlled segment which produced 3,905 tonnes grading 3.83 g/t Au and 46 g/t Ag.

The 29 Gap

The "29 Gap" is the northern part of the 29 area of the mine property. To date no mineralized bodies have been discovered in this portion of the mine yet several orebodies have been mined to the north in areas 30 and 31. Within the southern part of the 29 area the mine has exploited both manto and tronco orebodies with grades in excess of 4 grams of gold and over significant thicknesses yet the numerous late stage faults have resulted in no economic mineralization in the northeastern part of this area being located to date. One piece of the orebody, located in the 29 area, during 2008 resulted in the production of 57,000 tonnes that year (roughly 21% of the annual production) with an average grade of 4.17 g/t Au and 63 g/t Ag.

 

The San Martin project is located 50 km east of the City of Querétaro in Querétaro State, and about 250km northwest of Mexico City. High grade mineralization was discovered at San Martin in the 18th Century, and is reported to have been mined over a period of 40 years; however, no production records exist. Between 1900 and 1924, an estimated 250,000 tonnes grading 15 g Au/t and 100 g Ag/t was reportedly mined.


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In 1982, the area was declared a National Reserve; however, by 1986, Luismin had reached an agreement to conduct exploration/exploitation in the area. Mining began in 1993 at 300 tpd and the production increased on a yearly basis to the present rate of 747 tpd with the capacity of 900 tpd. Exploration has been concentrated along the NE trending breccia zone however evidence of a northerly trend in area 30 leads us to suspect possible other structures.

Mineralization is generally made up of breccia that commonly is concordant with a limestone/shale contact (in the San Martin and San Jose areas) which forms the relatively steeply dipping tronco deposits, these troncos contact the younger volcanic flows (dacite and ignimbrite) where the have formed the more horizontal manto portions of the deposit. At depth in the San Martin area the Guadalupe vein was found in 2007. This vein is sub parallel with the San Martin segment is more vein like and somewhat higher grade than the San Martin structure at the same elevation. Drilling and lateral development are being used to prove reserves in this vein whhich indicatess the potential for other similar structures.

The mineralized economic breccia grades from 30 g Ag/t to 250 g Ag/t together with 2.0 g Au/t to 30 g Au/t over widths that vary from 1.0 to 17.0 m but average 4.0 m. Mineralization occurs in Upper Cretaceous black limestone and calcareous shales of the Soyatal Mexcala Formation as electrum, and silver selenide minerals principally associated with quartz and to a lesser degree with calcite. The deposit is an epithermal, probably high sulphidation precious metal (Ag-Au) type (metal ratio Au:Ag at 1:10), related to a Tertiary dacitic/andesitic intrusive dome.


Proven and Probable Mineral Reserves - San Martin*
The total Proven and Probable Mineral Reserves estimated as of July 01, 2009 at San Martin are 1.03 million tonnes at a grade of 43 g Ag/t and 3.66 g Au/t as follows:

 

Tonnes

g Ag/t

g Au/t

Proven Reserves

301,069

15

2.42

Probable Reserves

461,867

38

3.38

  1. Reserves were estimated by Minera de la Pena Bernal July 1, 2009.
  2. Cutoff grades based on total operating cost were US$34.33/tonne.
  3. All reserves are diluted by 10%
  4. For widths greater than 5m a mining recovery factor of 85% has been applied.
  5. The tonnage factor is 2.55 tonnes per cubic metre.
  6. Cutoff values are calculated at a silver price of US$10.00 per troy ounce and US$700 per troy ounce for gold.
  7. Numbers may not add up due to rounding.
  8. San Martin tronco has area expanded to reflect average 55 degree dip
  9. Blocks in Guadalupe vein had high gold values cut to 20 g/tonne
Inferred Mineral Resources by area at the San Martin mine property as of July 1, 2009 and total about 1.57 million tonnes at an approximate grade of 40 g Ag/t and 3.65 g Au/t.

* Excerpt from the San Martin Technical report titled 'RESERVES AND RESOURCES IN THE SAN MARTIN MINE, MEXICO AS OF JULY 1, 2009', August 29, 2009.

Click here to view a Technical Review of the San Martin Project, Mexico July 01, 2009 (PDF 4.7MB)