GR Silver Mining Ltd. [GRSL-TSXV; GRSLF-OTCQB; GPE-FSE] reported high-grade silver results from underground infill drilling at the 100%-owned Plomosas project 94 km southeast of Mazatlan, Sinaloa state, Mexico. The results continue to support the potential to increase Ag grades in the Plomosas Mine Area resource. The drilling targeted high grade Ag mineralization in the upper levels of the underground workings, in areas where unsampled intervals from historical drill holes within the 2021 resource block model were previously assigned zero values.
Core drilling, in un-mined shallow areas (up to 160 metres below surface) of the historical Plomosas Mine, continues to define attractive wide and high-grade Ag mineralization. The presence of high-grade results with predominance of silver mineralization only in areas with potential to increase silver grade in planned update of resource model, including drill hole PLIP22-013 that returned 6.5 metres at 1,458 g/t silver (1,485 g/t AgEq – Silver Equivalent), including 0.9 metres at 3,118 g/t silver (3,266 g/t AgEq).
PLIP22-012 returned 14.0 metres at 146 g/t silver, including 0.4 metres at 2,474 g/t silver (2,542 g/t AgEq). PLIP22-011 returned 2.9 metres at 190 g/t silver, including 0.4 metres at 626 g/t silver. PLIP22-010 returned 8.3 metrres at 100 g/t silver.
Silver mineralization on the hanging wall of the main polymetallic Plomosas Breccia, in the upper levels of the underground workings, supports the upside potential for silver grades in the mineral resource update scheduled for Q1|23.
The combination of systematic underground mapping, 3D modelling of different styles of mineralization and underground infill drilling at the historic Plomosas Mine has defined attractive, wide, high-grade gold-silver (Au-Ag) mineralized zones. These new zones will be incorporated into the upcoming mineral resource block model and estimation.
Recent silver drill results provide encouragement for the Company to continue drilling underground at the Plomosas Mine Area in 2022 (Figure 1) with the objective of significantly increasing the Ag grade in areas of the resource model.
GR Silver Mining Chairman and CEO, Eric Zaunscherb, commented, “The 2022 infill drill program at the Plomosas Mine has been carefully designed to address upside potential in the resource block model. It has been our thesis that historical sampling lacked detail in some unmined areas resulting in the adoption of zero grade in unsampled drill hole intervals in the current resource model. This is supported by the observation that current resource model grades in areas already mined are lower than suggested by historical production grades. Further, it is very encouraging to see such high-grade Ag results confirming the existence of new, high-grade Ag zones associated with previously ignored cross-cutting structures. It is highly satisfying to see further proof of concept on both themes, with the potential for a commensurate re-rating.”
The underground infill drilling program at the Plomosas Mine Area commenced in March 2022 and is ongoing. The drill holes are predominantly short holes planned to target zones where recent geological mapping identified opportunities to improve the 2021 NI 43-101 mineral resource block model Ag grade, utilizing areas of the underground development that provide good access.
The underground drilling program is designed to, not only address the shortcomings in the 2021 resource model, but also delineate high-grade Ag-Au mineralized zones located between level 775 RL and 1025 RL.
A total of 13 holes have been completed underground to date in 2022. These intervals confirm consistent high-grade silver mineralization and have also delineated new mineralized zones in areas not previously drilled. Upon completion of the underground infill drill program in Q4|22, the company anticipates commencing a resource upgrade for the Plomosas Mine Area.
Drill holes PLIP22-10, PLIP22-11, PLIP22-12 and PLIP22-13 successfully discovered wide, high-grade silver mineralization hosted by hydrothermal breccias located in the hanging wall of the previously mined polymetallic (Ag-Au-Pb-Zn) hydrothermal Plomosas Breccia.
Drill holes from PLIP22-01 to PLIP22-09 consistently intersected high grade Ag-Au mineralization hosted in a polymetallic (Pb-Zn) hydrothermal breccia. All nine holes indicate the presence of multiple hydrothermal zones with silver results generally >200 g/t silver and individual gold grades up to 4.5 g/t gold in locations drilled along strike on the 1025 RL level.