Cachinal is a low-sulphidation epithermal deposit located in one of Chile’s top regions for silver and gold. Shallow drilling has defined the current mineral resources principally to a depth of 150 m below surface and provides sufficient evidence to interpret the presence of high-grade shoots within the vein system extending below the base of a potential open pit. Aftermath’s initial exploration focus is to test for mineralization that can potentially be mined using more economical, open pit extraction.
Located in Chile’s administrative Region II, Cachinal lies about 40 km east of the Pan American Highway in a nearly flat plain at an elevation of around 2,700 m above sea level. The project is situated 16 km north of Austral Gold’s Guanaco gold-silver mine.
Cachinal is located within the Paleocene Precious Metal Belt, to the west of, and parallel to the prolific northern Chilean porphyry copper belt. The Paleocene Belt hosts several significant low and high sulphidation epithermal gold-silver and silver-gold deposits including current producers such as Yaman’s El Peňón Mine, Austral Gold’s El Guanaco/Amancaya Mines and the former producing mines at San Cristobal and Vaquillas.
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
Classification | Material type | Tonnes (Mt) | Silver (g/t) | Gold (g/t) | Silver (Moz) | Gold (Koz) |
---|---|---|---|---|---|---|
Indicated | Open Pit | 4.83 | 97 | 0.13 | 15.03 | 20.05 |
Underground | 0.22 | 182 | 0.22 | 1.29 | 1.65 | |
TOTAL | 5.05 | 101 | 0.13 | 16.32 | 21.70 | |
Inferred | Open Pit | 0.17 | 73 | 0.07 | 0.41 | 0.43 |
Underground | 0.36 | 180 | 0.19 | 2.07 | 2.18 | |
TOTAL | 0.53 | 145 | 0.15 | 2.48 | 2.61 |
Notes on the Cachinal Mineral Resource Estimate
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.
Following completion of a detailed data compilation and the March site visit, the initial program for Cachinal has been finalised. Again, this work will commence as soon as practicable after the COVID-19 movement restrictions are lifted.
Field work will commence with a remote 3D laser survey of the historic mining voids. The Company is in the process of obtaining quotations. This will provide an accurate assessment of the historic mining.
On the main mineralised structures, a program of 3,500 m of reverse circulation and diamond drilling has been designed. This program will utilise existing drill sites to minimise disturbance and covers the 2 km of known strike length. Core from this program will also be used to advance metallurgical test work.
We will also conduct an inventory of existing historic run-of-mine stockpiles and leach pads. Historic sampling of these could provide sufficient evidence to warrant more detailed systematic surface sampling. If results are positive, they will be used to justify a sonic drilling program over the stockpiles.