La Buena Project
|Location:||Northern Zacatecas, Mexico, 4km North of Goldcorp's La Negra/Noche Buena resource area, 9km North of the Peñasquito mine, 1.5km west of the Dia Bras Las Coloradas resource area|
|Area:||Three concessions, approximately 8,500 hectares|
|Minerals:||Gold, Silver and Base Metals|
|Status:||No drilling, past artisanal mining|
|Ownership:||100% (Subject to a sliding scale NSR royalty to Golden Minerals)|
An option was granted to Exeter Resource Corporation to acquire interests in La Buena property:
- $15M of exploration funding and $650,000 in cash payments over 5 years to earn 60% interest.
- Year 1 exploration must include 2,500 meters of drilling.
- 60% earn-in must include a preliminary economic assessment as defined by NI43-101 standards.
- San Marco to operate until $6M of exploration expenditures completed.
- All cash payments to be by way of private placement purchase by Exeter of San Marco's common shares.
- The La Buena property is next door to one of Mexico's largest open pit mines - Goldcorp's Peñasquito Mine
- La Buena property hosts a similar geological environment to Peñasquito, a world-class gold, silver, lead and zinc deposit
- Detailed geological mapping, ground magnetometer surveys, IP surveys & surface geochemistry has been completed, resulting in multiple drill targets
- Permitting for drilling as well as surface rights contracts are in place
- Drilling of coincident geophysical and gold in soil geochem anomaly in Julia Zone
- Soil geochem has confirmed a coincidence of elevated gold content with the previously identified and undrilled geophysical anomaly
- Four hole 2000m drill program
- Field work and drilling in the San Lucas Zone
- San Lucas has old workings including shafts and geological features that are similar to features underlying Goldcorp's Penasquito Mine
- Four hole 1200m drill program
- Continued geological mapping, geophysical and geochemical works in other areas of the property to identify new drill targets
There are at least 2 different areas on the property where artisanal mining occurred and it was done from surface cuts, shallow stopes and is mainly exploratory in nature. Kennecott staked a concession over the zone of metasediments that occurs in the northwest part of the concession in 1998, but the concession was abandoned shortly thereafter and declared open ground in November 2002. Golden Minerals (Minera de Las Cordilleras) staked much of the ground that comprises the La Buena project and received title to the concession in June 2007. Their exploration effort consisted of limited reconnaissance rock-chip sampling. San Marco acquired the Golden Minerals concessions in 2010.
Shallow alluvium covers nearly half of La Buena property, however where outcrop exists, Caracol Formation (mainly calcareous siltstones) dominates the property geology. The same shelf carbonates that host ore in the Zuloaga, Noche Buena, and Providencia districts are found at the north end of La Buena property along the hinge-line of an east‑west anticline that forms a prominent ridge called the Sierra de Zuloaga. Subvolcanic pyrite‑rich monzonitic intrusives occur a few kilometers to the south of the ridge, forming a halo of metasediments in the local Caracol Formation that San Marco refers to as the Julia zone. The Julia zone is situated along the axis of an east-west syncline that is overturned to the north.
On La Buena property, prospect pits and shallow workings have been found on chimneys and mantos in reef limestones, as well as along structures in metasediments and Tertiary intermediate subvolcanics. The Cupido Formation hosts the chimney-style mineralization. Within the Julia zone, gold of economic interest occurs as disseminations in Caracol Formation metasediments as well as subvolcanics. Soil sampling in the Julia zone returned anomalous values (between 50 and 665ppb gold) over an area of roughly 1km by 1km. Limited sampling of the dumps and workings found on La Buena property have returned gold assays as high as 5.56 g/t gold. Intrusive and sub-volcanic rocks are associated with ore throughout the Concepción del Oro district.