Maria: Geology and Minerals

For more complete descriptions please see the recent 43-101 report by Luc Rioux, P.Geo.

Mineralization
The mineralization occurs as chimneys, veins and mantos that are mainly comprised of oxides and sulphides of silver, lead, zinc, copper, mercury and antimony. The surrounding wall rocks are the limestone’s of the El Doctor Formation. The lutites of the Soyatal Formation are associated with a deep rooted granodioritc to dioritic stock located at greater depths. Close to the contact there is some moderate temperature mineralization represented by silver, lead, zinc and copper, whereas the periphery of the contact is delineated by lower temperature type of mineralization such as mercury and antimony.

The 1998 COREMI study of this deposit has classified it as being of epithermal origin. The mineralization is defined as occupying the spaces between the layers of the sedimentary rocks, the crosscutting fractures and in some cases within cavities of dissolution. The suspected intrusive body (granodiorite to diorite) is not observed within the mine workings but is expected to possibly be found at greater depths.

Minerals of lesser importance are iron oxides and sulphides of silver, lead, zinc and antimony. Minerals such as stibnite, galena, sphalerite along with sulfosalts of silver and native silver and smithsonite, jarosite have been reported within the mine workings. The gangue minerals are for their part composed mainly of calcite and minor rhodochrosite.

90% of the deposit is found as a “manto” type deposit. The remaining 10% is located within mineralized fractures. The “manto” has a general strike of N280° with a dip of 30° to the SW, it is 80 meters long and varies between 30 centimeters and 5 meters in thickness.

Current State of Mine Workings
The current mine workings at the San Juan Nepomuceno mine now extend for a length of 1,440 meters subdivided into shafts, crosscuts, raises with average mining widths of 2.0 x 2.0 meters. These workings were done in order to extract mainly mercury.

The Socavon crosscut: it is a crosscut mostly located in gangue rock that was established to connect the Santo Entierro and Maconi mine workings with the El Doctor shaft. It is 720 meters long with a general azimuth of N283°. It was established mainly for ventilation purposes and hauling the ore to the mill site.

The El Doctor shaft: It was originally a 30 meters deep vertical shaft but was deepened for 500 meters on a 30° inclined angle.

Inclined shafts within the Socavon crosscut: At the far end of the Socavon crosscut an inclined shaft was made which is 100 meters long on a 20° incline. This inclined shaft communicates with another one which is 475 meters long on a 45° incline. Approximately 275 meters from this last working there is a 40 meters long crosscut with at the end a 20 meters deep vertical shaft.

Until the Pleistocene Era. Along with the withdrawing of the oceans more terrigenous sedimentary rocks were deposited which formed the Tarango Formation and in the Quaternary Period. These were the last expressions of the basaltic volcanism.

Local Geology
Within the property limits and the mine workings, the outcrops are comprised of the El Doctor Formation (Lower Cretaceous) and in concordance with this Formation was deposited the Soyatal-Mezcala Formation (Middle to Upper Cretaceous). All the mine workings are located within the El Doctor Formation in the La Negra and Cerro Ladron facies.

The La Negra Facies: is comprised of carbonated lutites and black coloured, moderately to strongly fractured limestones in layers of 10 to 30 centimeters thick which serve as country rock for the mineralization, not only within the mine itself but also in most of the San Joaquin area. The La Negra facies can be correlated with the Cuesta del Cura Formation in other areas of Mexico and is associated with a shallow carbonated basin type of depositional environment.

The Cerro Ladron facies: is a light to dark grey coloured, moderately fractured limestone with beds ranging in thickness from 90 centimeters to 5 meters.

In the general vicinity of the mine area, dioritic to granodioritic intrusive bodies outcrop here and there. They can be observed in the surrounding mines (el Monte, el Carrizal, Santo Entierro, and Flor de Mayo) in which skarn type deposits have been outlined.

No intrusive was ever delineated within the mine workings of the San Juan Nepomuceno mine. Although geophysics carried out by COREMI suggest that there might be some intrusive stocks at greater depths.

Structural Geology
The area has undergone intense fracturation associated with the Laramide Orogen and possibly with the intrusion of a granitic stock at lower depths. Locally the mine is located within the Maconi Syncline. Conjugated faulting exhibit two (2) preferred orientations: one is N-S with a dip of 40° to the E, the other one is NW-SE with a dip to the SW. It is believed that the mineralization is mostly concentrated within the second set of faults (NW-SE).