Gold, Silver
Oaxaca, Mexico
Nearest City:
Oaxaca City 170 km (Combined Population ~ 350,000)
Excellent road access, skilled labor nearby
Water and power access
Experienced Mexican geologists and local technical labor
San Juan LaJarcia, San Bartolo Yautepec
12,260 hectares
Option to acquire 100%



  • Comprises over 12,000 hectares of high-potential epithermal targets  22 km’s southeast of Gold Resource Corporation’s currently producing Arista-Switchback mines and 8km to the northwest of  Gunpoint Exploration’s La Gitana project. 
  • Epithermal veining and alteration are focused along a 17 km northwest-striking caldera structural margin that matches the  orientation of the high-grade polymetallic Au-Ag veins at Gold Resource Corp’s Arista-Switchback mines. 
  • Important geologic indicators include the presence of multiple mineralized veins, paleo-hot-spring (sinter) deposits, iron-rich travertines, rhyolite domes, and hydrothermal breccias, all of which are locally anomalous to well-mineralized with Au-Ag and base metals.
  • A newly discovered multiple-kilometer high-potential epithermal center was recently identified in the southern portion of the project.
  • Flanking the caldera-margin structures to the east and southwest are Ag and base metal-rich skarns, the full extents of which are not yet known.
  • Outside the areas of active mining the region has seen little systematic exploration, and the Yautepec project is the most highly prospective segment of the regional structural trend.


Caldera associated-tertiary volcanic rocks highly prospective for hosting epithermal precious metal mineralization, similar to nearby producing mines. The mapped altered rocks along the trend are part of a nearly 100km-long structural- volcanic corridor that extends from the San Jose mine (Fortuna Silver) to the northwest, to Chesapeake Gold’s Gitana project to the southeast. 

Trace of 20km Caldera Margin with high potential for undiscovered Bonanza grade epithermal Systems.


Two rounds of reconnaissance mapping and geochemical sampling that have revealed widespread metal anomalies in multiple areas on its Yautepec project. The exploration efforts are being focused on a 22-kilometer zone consisting of a geological structure similar to those known to host bonanza type epithermal systems at the nearby producing San Jose (Fortuna Silver Mines Inc., TSX: FVI) and Arista-Switchback (Gold Resource Corp., NYSE: GORO) mines.

A total of 162 samples were taken of prospective rock types, with a focus on high potential areas identified during the first period of work as discussed in a prior news release dated July 16, 2019. Significant new results include:

Yautepec Project: Significant 2nd period sample results (ALS Labs)

  Element Maximum values Lithology of highest value Samples with Significant values
Precious metals Ag 308 grams Quartz vein bounding silica sinter complex 11 > 10 grams
Au 1.07 grams Quartz vein bounding silica sinter complex 11 > 0.20 grams
Base metals Cu 99 ppm Sinter complex: silica-carbonate 12 > 50 ppm
Pb 464 ppm Quartz vein - brecciated 17 > 100 ppm
Zn 548 ppm Quartz vein bounding silica sinter complex 14 > 100 ppm
Mo 102 ppm Quartz vein - brecciated 3 > 50 ppm
Pathfinder elements As 9.26% Felsic intrusion - brecciated 18 > 1000 ppm
Ba 3780 ppm Hydrothermal breccia 17 > 1000 ppm
Hg 29.5 ppm Sinter: silica - carbonate 18 > 1 ppm
Sb 307 ppm Sinter complex: breccia 8 > 100 ppm
Se 16.7 ppm Felsic intrusion - brecciated 30 > 2 ppm
Te 5.27 ppm Quartz vein bounding silica sinter complex 19 > 0.20 ppm
Tl 3.35 ppm Sinter complex: silica 10 > 1 ppm

To date, exploration sampling has yielded silver values up to 308 grams and gold values to 1.07 grams in an historically undocumented quartz vein system of impressive length with structural widths up to 7 meters, based on surface mapping to date. In tandem with the adjacent mineralized hot springs complex (sinter), we have generated a series of high priority drill targets after only two periods of fieldwork.

Exploration Potential

The majority of new samples were collected from a quartz vein system exposed along a 530-meter northwest-southeast trend, and as well from an immediately adjacent fossil hot springs system (sinter), developed along the same trend for 770 meters with widths up to 215 meters (~95,000 square meters minimum surface area).  These and prior results show that both the quartz vein system and sinter complex are mineralized and are logically genetically related. The presence of sinter indicates that the full vertical extent of potential bonanza style epithermal mineralization is conserved at depth, this inferred from the fact that most known systems of this style are not well mineralized within 150 meters of documented ‘paleo’ surfaces (Sillitoe, 2015*). The northwest-southeast structural trend of the quartz vein and sinter complex is similar to that of nearby producing mines on the Oaxaca epithermal Au-Ag belt, such as Gold Resource Corp’s [NYSE: GORO] Arista-Switchback mine, and Fortuna Silver Mines’ [TSX: FVI] San Jose mine.

Work Plan

The targets identified to date represent a small portion of the greater Yautepec project; multiple outlying exploration targets await further work which could potentially yield similar encouraging results.  Madoro has planned additional field work to test soil samples and is planning a maiden drill program to test high priority targets in areas with previously-encountered mineralization. 

Rob Johansing, M.S., C.P.G. Consulting Geologist, a qualified person in accordance with NI 43-101, has reviewed and accepted the technical information in this news release.