La Parrilla Project
Durango, Mexico
Overview
La Parrilla is located in Durango State, Mexico, approximately 76 kilometres southeast of Durango's capital and comprises 41 contiguous mining concessions in good standing, covering 69,478 hectares.
The property was in production continuously between 2005 and September 2019, when it was placed on care and maintenance. During this period, the complex collectively produced 34.3 million silver-equivalent ounces. La Parrilla hosts five underground mines surrounding the mill, including Rosarios, La Rosa, San Jose, Quebradillas and San Marcos, and the Quebradillas open pit. Silver Storm owns 100% of The La Parrilla Project, which was acquired in August 2023 from First Majestic Silver.
Processing Plant
The metallurgical processing plant at La Parrilla consists of parallel 1,000 tpd flotation and 1,000 tpd cyanidation leach circuits to treat both oxide and sulfide ores for a total capacity of 2,000 tpd, using a conventional flowsheet.
Both ore types are polymetallic, containing silver as their principal economic component as well as significant amounts of lead and zinc and minor amounts of gold. Oxide ore is processed by cyanide leaching to produce doré bars while sulphide ore is processed by differential flotation to produce a silver-rich lead concentrate and a zinc concentrate.
Mineralization at La Parrilla occurs in veins and replacement deposits, the locations of which are structurally controlled by pre-existing faults, fractures, and bedding planes.
Veins can be either open space filling, forming massive sulphide and breccia veins, or fault-related, consisting of matrix-supported breccias or gouge containing disseminated sulphides and oxides. The La Parrilla deposits contain primary sulphides. Due to supergene oxidation, the primary sulphides in the upper parts of some deposits have been altered.
Geology and Mineralization
Mineral Resource Estimate
Mineral Resource Estimates have been completed for 22 veins of the Rosarios, San Marcos and Quebradillas zones comprising both oxide and sulphide mineralization.
The validated data effectively used in the Mineral Resource estimation includes 2,025 core samples (1,271 metres), from 392 different boreholes piercing the mineralized structures of La Parrilla, and 9,676 chip samples (5,148 metres), taken from 3,190 underground channels by FMS within these structures. The solid models representing 22 veins were built by FMS using implicit modelling guided by the borehole geological logging, core and channel samples grades, and, where available, underground mappings.
La Parrilla Mineral Resource Estimate
Initial Silver Storm Resource – August 2023
SRK Consulting (Canada) Inc., May 31, 2023.
| Category and Mineral Type | Quantity (kt) | Grade | Contained Metal | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Silver (g/t) | Gold (g/t) | Lead (%) | Zinc (%) | AgEq (g/t) | Silver (koz) | Gold (koz) | Lead (kt) | Zinc (kt) | AgEq (koz) | ||
| Indicated Oxides | 93 | 238 | 0.16 | - | - | 253 | 713 | 0.5 | - | - | 756 |
| Indicated Sulphides | 522 | 165 | 0.07 | 1.83 | 1.63 | 264 | 2,770 | 1.2 | 9.6 | 8.5 | 4,437 |
| Total Indicated Resources | 615 | 176 | 0.08 | 1.55 | 1.39 | 263 | 3,483 | 1,7 | 9.6 | 8.5 | 5,193 |
| Inferred Oxides | 445 | 246 | 0.10 | - | - | 256 | 3,525 | 1.5 | - | - | 3,657 |
| Inferred Sulphides | 812 | 161 | 0.113 | 1.53 | 1.56 | 255 | 4,207 | 3.5 | 12.4 | 12.7 | 6,672 |
| Total Inferred Resources | 1.257 | 191 | 0.12 | 0.99 | 1.01 | 256 | 7,731 | 5.0 | 12.4 | 12.7 | 10,328 |
Notes for the Mineral Resource Estimate for La Parrilla as described in the ‘Independent Technical Report for the La Parrilla Silver Mine, Durango State, Mexico’, prepared by SRK Consulting, dated August 10, 2023 and available under the Company’s profile on www.sedarplus.ca or the Silver Storm website www.silverstorm.ca.
Block model estimates audited by David F. Machuca-Mory, PhD, PEng, Principal Consultant (Geostatistics), and Ilkay Cevik, PGeo, Associate Consultant (Geology), SRK Consulting Canada Inc.
Mineral Resources are not Mineral Reserves and do not have demonstrated economic viability.
Mineral Resources have been classified in accordance with the Canadian Institute of Mining, Metallurgy and Petroleum ("CIM") Definition Standards on Mineral Resources and Mineral Reserves.
All figures are rounded to reflect the relative accuracy of the estimates.
Reasonable prospects of eventual economic extraction were considered by applying appropriate cut-off grades, removing unrecoverable portions of the estimates, and reporting within potentially mineable shapes.
Metal prices considered were US$22.50 /oz Ag, US$1,800 /oz Au, US$0.94 /lb Pb and US$1.35 /lb zinc.
The cut-off grade considered for oxide and sulphide block model estimates were, respectively US$140 g/t Ag-Eq and US$125g/t Ag-Eq. They are based on 2017 costs adjusted by the inflation rate and include sustaining costs.
Metallurgical recovery used for oxides based on weighted 2015-2017 actuals was 70.1% for silver and 82.8% for gold
Metallurgical recovery used for sulphides based on weighted 2015-2017 actuals was 79.6% for silver, 80.1% for gold, 74.7% for lead and 58.8% for zinc.
Metal payable used was 99.6% for silver and 95% for gold in doré produced from oxides.
Metal payable used was 95% for silver, gold and lead and 85% for zinc in concentrates produced from sulphides
Silver equivalent grade is estimated as: Ag-Eq = Ag Grade + [ (Au Grade x Au Recovery x Au Payable x Au Price / 31.1035) + (Pb Grade x Pb Recovery x Pb Payable x Pb Price x 2204.62) + (Zn Grade x Zn Recovery x Zn Payable x Zn Price x 2204.62) ] / (Ag Recovery x Ag Payable x Ag Price / 31.1035)
Tonnage is expressed in thousands of tonnes, metal content is expressed in thousands of ounces or thousands of tonnes
Totals may not add up due to rounding
Independent Technical Report for the La Parrilla Silver Mine, Durango State, Mexico
Technical Report - NI 43-101
