The Cachinal epithermal silver-gold deposit is the most important exploration target on the project. This deposit was mined from underground workings during the 20th century. Sporadic drilling by previous owners of the project since 2005 has delineated near-surface silver-gold mineralization associated with a network of steeply dipping, north-to-northwest trending low-sulphide quartz veins.
The epithermal veins and breccias have been recognized by trenching and drilling over a strike length of at least 2 km and are known to have been mined to a depth of at least 300m. They range in thickness from a few centimetres to 2m, reaching up to 20m locally at the intersection of two structures. The main veins trend north-northwest and northwest with a secondary set trending east-northeast to east-west, best developed at the southern end of the deposit.
In September 2020, the Company published a current CIM2019 compliant Mineral Resource estimate for Cachinal, summarised in Table 1 below.
See amended and restated technical report entitled “Amended Independent Technical Report for the Cachinal Silver-Gold Project, Region II, Chile” with an effective date of September 11, 2020 has been filed under the Company's profile on SEDAR. It was prepared in accordance with the Canadian Securities Administrators’ National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”)
The Mineral Resource estimate was performed by independent qualified persons Glen Cole P.Geo of SRK Consulting (Canada) Inc., and Sergio Alvarado Casas, CMC of Geoinvest SAC E.I.R.L. (Chile).
Table 1. Summary of the CIM Compliant Mineral Resource Estimate for the Cachinal Silver-Gold Project
Notes on the Cachinal Mineral Resource Estimate
- For full details on the Cachinal Mineral Resource estimate please refer to the NI 43-101 technical report titled “Independent Technical Report for the Cachinal Silver-Gold Project, Region II, Chile.” By Qualified Persons G. Cole, (P.Geo) of SRK Consulting (Canada) Inc and S. Alvarado Casas, of Geoinvest SAC E.I.R.L. (Chile), dated September 11, 2020 with an effective date of August 10, 2020, filed on the Aftermath Silver SEDAR profile.
- Cachinal mineral resources were classified according to the CIM Definition Standards for Mineral Resources and Mineral Reserves (May 2014).
- Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability.
- All figures have been rounded to reflect the relative accuracy of the estimates.
- Cut-off grades are based on metal price assumptions of US$22.00 / ounce of silver and US$1,550 / ounce of gold, and metallurgical recoveries of 85% for both silver and gold using milling and cyanide leaching.
- The portion of the Mineral Resources that has been determined to be amenable to extraction through Open Pit methods uses a cut-off’s of 30 g/t Silver equivalent.
- The open pit Mineral Resource is constrained within Lerchs-Grossman optimised pit shells that assume mining dilution & losses of 2.5%, 50-degree overall slope angles, mining costs of $2/t rock, general and administrative costs of $2/t rock, processing costs of US$15/t for processing using milling and cyanide leaching.
- The portion of the Mineral Resources deemed to be amenable to extraction through underground methods are reported at a cut-off of 150 g/t Silver Equivalent. This assumes a mining cost of US$90/t, general and administrative costs of $2/t and a processing costs of US$15/t for agitated leaching.
The oxidation level bottoms at about 120 m to 150 m below surface; however, the down-dip extent of the mineralized structures remains unknown. Gold and base metal grades are generally observed to increase at depth.