Peñasco Quemado, is located in northern Sonora, 60 km south of the town of Sasabe on the US-Mexican border and comprises 3,746 hectares in seven concessions. A 2006 drilling program outlined a historical measured and indicated resource of 2.57 million tonnes at a grade of 117 g/t Ag for a silver resource of 9.63 million ounces. The silver mineralization is associated with manganese oxides in a near surface shallow westerly dipping zone of polymictic conglomerate in the northern part of the deposit and in stockwork quartz and manganese oxides in a rhyolite dome in the southern part of the deposit. The mineralization has been traced along a 2 km strike length and drilling to date has been relatively shallow, less than 100m deep, mainly focused on the silver-bearing conglomerate.

Historical Mineral Estimate

** Silvermex Resources Limited reported in a technical report titled “Updated NI 43-101 Technical Report and Resource Estimate for the Penasco Quemado Silver Property” dated March 9, 2007 (filed on SEDAR on March 16, 2007), prepared by William J. Lewis and James A. McCrea, the above historical mineral estimate.  The historical mineral estimate used “measured mineral resource”, “indicated mineral resource” and “inferred mineral resource”.  Although these categories are set forth in NI 43-101 and CIM, CIM has revised its definitions for mineral resources since the completion of the technical report that supports this resource estimate.  Accordingly, Plymouth considers these historical estimates reliable as well as relevant as it represents a target for exploration work by Plymouth.  The data base for the historical resource estimate consisted of 24 reverse circulation holes from a 1981/82 program, 17 reverse circulation holes from a 2006 program and 8 diamond drill holes from a 2006 drill program.  Assay data was available for all 49 of the drill holes and 12 trenches.  The mineral resource estimate used a kriging estimation method to establish mineralized zones with a cut-off grade of 30 g/t Ag and assay’s capped at 700 g/t Ag. Resource blocks were estimated by ordinary kriging with samples within a search radius of 25 meters classified as a measured mineral resource, within 47 meters classified as an indicated mineral resource and within 70 meters classified as an inferred mineral resource. As required by NI 43-101, CIM definitions (August, 2004) were used to classify mineral resources with the classification of each kriged mineralized block dependent upon the number of penetrating holes. An in-situ block density of 2.50 t/cu meter was assigned the mineralized blocks.  The qualified person has not done sufficient work to classify the historical estimate as a current mineral resource therefore Plymouth is treating these historical estimates as relevant but not current mineral resources.