• Advanced Exploration

Growth | Pitarrilla

Pitarrilla, one of the largest undeveloped silver projects in the world, is expected to form one of the key cornerstones of Endeavour’s long-term growth profile.

Pitarrilla Project, Mexico

Pitarrilla is a large undeveloped silver, lead, and zinc project located 160 kilometres north of Durango City, in northern Mexico. The project is within the Municipality of Santa María del Oro and Indé on the eastern flank of the Sierra Madre Occidental mountain range. There are several mines in operation in Durango, including our Guanacevi mine, which has been in operation since 2005. The property comprises of 4,950 hectares across five concessions and has significant infrastructure in place with direct access to utilities, including access to the grid. A number of key permits are already in place for underground mining and development, including permits for water use and discharge, general use of explosives, change use of soil, as well, underground mining and development are permitted under an Environmental Impact Statement.

Prior to Endeavour’s acquisition, Pitarrilla was owned by SSR Mining Inc. (NASDAQ/TSX: SSRM; ASX: SSR). From 2003 to 2012, SSR Mining conducted extensive drill campaigns on the project. Concurrently, SSR Mining published two technical reports, consisting of a prefeasibility study in 2009 focused on a high-grade underground mine scenario and a feasibility study in 2012 which evaluated an open-pit concept. Endeavour acquired the Pitarrilla Project from SSR Mining in 2022. Endeavour plans to evaluate various scales of production, including an underground option, which would strengthen the long-term production profile of the Company and provide significant value to shareholders.

Endeavour Silver published an initial mineral resource estimate on the Pitarrilla project, following the completion of the acquisition and filed a technical report, prepared by SGS Geological Services.

The following information is derived from the 2022 Pitarrilla Report:

The total Indicated Mineral Resources (open pit and underground) at Pitarrilla totals 158.6 million tonnes containing 491.6 million ounces (oz) silver (Ag) grading 96.4 grams per tonne (gpt), 1.1 billion pounds (lbs) of lead (Pb) grading 0.31%, 2.6 billion pounds of Zinc (Zn) grading 0.74% for a total of 693.9 million ounces of silver equivalent (AgEq) grading 136 gpt.

The Inferred Mineral Resource (open pit and underground) totals 35.4 million tonnes containing 99.4 million oz Ag grading of 87.2 gpt, 281 million lbs Pb grading 0.36%, 661 million lbs Zn grading 0.85% for a total of 151.2 million ounces AgEq grading 132.7 gpt.

Silver equivalent grades are calculated using this formula: Ag (gpt) + [Pb (%) X 2204.6 X Pb Price / Ag Price X 31.1] + [Zn (%) X 2204.6 X Zn Price / Ag Price X 31.1] with price assumptions of Pb $1.00, Zn $1.30 and Ag $22.00.

Pitarrilla Mineral Resources Summary (effective as of October 6, 2022):

Cut-off Grade
(AgEq g/t)
Grade Contained Metal
Ag (gpt) Pb (%) Zn (%) AgEq (gpt) Ag (Moz) Pb (Mlb) Zn (Mlb) AgEq
In Pit (Oxide and Transition)
50 133.9 87.1 0.19 0.48 112.3 375.1 547 1,409 483.2
50 25.6 76.4 0.14 0.48 100.2 63.0 80 272 82.7
Underground (Sulphide)
150 24.8 146.1 1.01 2.14 264.4 116.5 551 1,172 210.7
150 9.8 115.5 0.93 1.80 217.5 36.4 202 389 68.6
Total In-pit and Underground (Oxide, Transition and Sulphide)
50 and 150 158.6 96.4 0.31 0.74 136.0 491.6 1,098 2,580 693.9
50 and 150 35.4 87.2 0.36 0.85 132.7 99.4 281 661 151.2


  1. The classification of the current Mineral Resource Estimate into Indicated and Inferred Mineral Resources is consistent with current 2014 CIM Definition Standards - For Mineral Resources and Mineral Reserves.
  2. All figures are rounded to reflect the relative accuracy of the estimate and numbers may not add due to rounding.
  3. All Mineral Resources are presented undiluted and in situ, constrained by continuous 3D wireframe models, and are considered to have reasonable prospects for eventual economic extraction.
  4. Mineral Resources which are not mineral reserves do not have demonstrated economic viability. An Inferred Mineral Resource has a lower level of confidence than that applying to an Indicated Mineral Resource and must not be converted to a Mineral Reserve. It is reasonably expected that the majority of Inferred Mineral Resources could be upgraded to Indicated Mineral Resources with continued exploration.
  5. It is envisioned that parts of the Pitarrilla deposit (oxide and transition mineralization) may be mined using open pit mining methods. In-pit mineral resources are reported at a cut-off grade of 50 g/t AgEq within a conceptual pit shell, which has been limited to the base of the transition mineralization.
  6. The results from the pit optimization are used solely for the purpose of testing the “reasonable prospects for economic extraction” by an open pit and do not represent an attempt to estimate mineral reserves. There are no mineral reserves on the Property. The results are used as a guide to assist in the preparation of a Mineral Resource statement and to select an appropriate resource reporting cut-off grade.
  7. It is envisioned that parts of the Pitarrilla deposit (sulphide mineralization) may be mined using underground mining methods. Underground (below-pit) Mineral Resources are estimated from the bottom of the pit (base of transition mineralization) and are reported at a base case cut-off grade of 150 g/t AgEq. The underground Mineral Resource grade blocks were quantified above the base case cut-off grade, below the constraining pit shell and within the constraining mineralized wireframes. At this base case cut-off grade the deposit shows good deposit continuity with limited orphaned blocks. Any orphaned blocks are connected within the models by lower grade blocks and are included in the Mineral Resource estimate.
  8. Based on the size, shape, location and orientation of the Pitarrilla deposit, it is envisioned that the deposit may be mined using low cost underground bulk mining methods (i.e. longhole mining).
  9. High grade capping of Ag, Pb and Zn was done on 1.50 metre composite data.
  10. Bulk density values were determined based on physical test work from each deposit model and waste model.
  11. AgEq Cut-off grades consider metal prices of $22.00/oz Ag, $1.00/lb Pb and $1.30/lb Zn and considers variable metal recoveries for Ag, Pb and Zn: oxide and transition mineralization - 75% for silver, 70% for Pb and 65% for Zn; sulphide mineralization - 86% for silver, 91% for Pb and 85% for Zn.
  12. The pit optimization and in-pit base case cut-off grade of 50 g/t AgEq considers a mining cost of US$2.50/t rock and processing, treatment and refining, transportation and G&A cost of US$22.40/t mineralized material, an overall pit slope of 42° for oxide and 48° for transition and metal recoveries. The below-pit base case cut-off grade of 150 g/t AgEq considers a mining cost of US$46.50/t rock and processing, treatment and refining, transportation and G&A cost of US$30.90/t mineralized material.
  13. The estimate of Mineral Resources may be materially affected by environmental, permitting, legal, title, taxation, socio-political, marketing, or other relevant issues.


Located in Durango State, which has a history of mining and is known as a mining-friendly jurisdiction, Pitarrilla is ~160 kilometres north of Durango City, where Endeavour’s exploration office and team reside. The project is easily accessible and has excellent infrastructure, including access to the power grid and a skilled workforce.


4,950 hectares (1.3 km x 0.6 km), consisting of 5 mineral concessions.


Intermediate sulphidation epithermal system.


Pitarrilla is expected to be one of the key cornerstones of Endeavour’s long-term growth profile. It is anticipated that it will be accretive on a silver equivalent resource per share, provide optionality in a rising silver price environment and help us to maintain our high exposure to silver.

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