The Cerro Bayo Mine Project is centred approximately 10km west of the township of Chile Chico in Chile’s XI Region,and features historical production of 650koz Au, 45Moz Ag at average grades of 5.42 g/t AuEq1 (2.81 g/t Au, 196 g/t Ag). The project comprises 285 sq.km of highly prospective epithermal gold and silver brownfields & greenfields potential with +100 identified veins and an existing gold-silver flotation plant.
Following shareholder approval obtained on 27 November 20212, Equus completed its acquisition of the Cerro Bayo Project in Region XI, Southern Chile from Mandalay Resources Corporation (TSX:MND, OTCQB: MNDJF) and took control of the Cerro Bayo Project area and mine infrastructure (Figure 1). Consideration for the acquisition was the issue to Mandalay of 19% of Equus’s share capital at the time of exercise. Additionally, Equus will pay a 2.25% NSR on future production from the Cerro Bayo Mine District claims, payable once production reaches 50,000 gold equivalent ounces, which is subject to a re-purchase option in favour of Equus.
The turn key mine infrastructure is central to the larger exploration package and existing resources2.
Figure 1 – Location plan of Equus Mining’s Cerro Bayo mining district and logistics routes, and other projects
The project includes an operational 1,650tpd flotation processing plant which under Mandalay commenced processing of low-grade stockpiles in late February 2021, having been on care and maintenance since 20163. The mine infrastructure also includes a permitted tailings storage facility, power generation, and some of the fixed and mobile plant required for a restart of mining of insitu resources. Mandalay produced 5,304 oz Au and 266,596 oz Ag from the processing of low-grade stockpiles from 20 Feb 2021 until the acquisition by Equus on 1 December 2021. Equus continued processing until suspension of stockpile processing on the 17 October 20224. Equus produced a total of 5,328 oz Au and 281,216 oz Ag over the 12 months ending 31 December 2022.
On the 17th October 2022, the Company announced5 the suspension of stockpile processing and a return to an exploration focus at Cerro Bayo.
Within the expansive mining claim package at Cerro Bayo, Equus is evaluating potential for future higher grade feedstock for the plant based on several potential sources which include the JORC 2012 compliant inferred resource at Taitao of 302koz gold equivalent at 2.5 g/t Au equivalent6 and the remnant 2017 NI 43.101 resource at the Marcela-Raul Mine of 73.0 Koz AuEq7 @ 6.3 g/t AuEq7 (29.7Koz Au @ 2.56 g/t Au, 3.25Moz Ag @ 280 g/t Ag)8.
In parallel, the Company is aggressively exploring what it believes to be compelling potential at our Appaloosa, Taitao and Pegaso Targets and other highly prospective areas throughout the Cerro Bayo district that the Company considers underexplored.
EXPLORATION: TAITAO- APPALOOSA VEIN-BRECCIA TARGET DRILLING
To date the Company has announced significant high-grade gold and silver drill results principally from within an approximate 150m long, north-south trending extension of the Appaloosa fault – breccia complex, below and to the east of the central eastern margin of the Taitao Pit, and subvertical splay veins in the hangingwall to the Appaloosa Fault- Breccia (Figures 2 & 3).
Drilling was primarily focused on testing extensions of:
- Epithermal vein-hydrothermal breccia hosted in the 10-30m wide, low-angle (35-45°) easterly dipping Appaloosa Fault complex, both along strike and down dip, of the previously reported holes CBD0829: 4.14m @ 17.9 g/t AuEq7and CBD10210: 8.76m @ 8.05 g/t AuEq7and CBD10410: 4.89m @ 8.5 g/t AuEq7 and 7.44m @ 5.68 g/t AuEq7
- High-grade steeply dipping hangingwall splay epithermal veins adjacent to the Appaloosa fault-breccia complex which are not exposed at surface in outcrop.
The westernmost surface expression of the Appaloosa vein-breccia complex is interpreted to broadly correspond to the historic Taitao Pit (see Figure 3). Historical production from the Taitao Pit from between 1995-2002 totaled approximately 153Koz AuEq7 @ 3.4 g/t AuEq7 (1.9 g/t Au, 115 g/t Ag)11 over pit dimensions of <35m depth x 30-200m wide x 1,400m length.
Figure 2 – Plan view showing location of Appaloosa Fault-Pegaso II- V targets, location of cross section A -A´ with summary results (Figure 3), historic production of the Taitao Pit, and historic underground mine workings and summary resources of the Delia, Dagny, Fabiola and Coyita Mines
Drilling was focused on testing extensions of epithermal vein-hydrothermal breccia hosted in the 10-30m wide, low-angle (30-45°) easterly dipping Appaloosa vein-breccia complex, both along strike and down dip, of previously reported holes including CBD082: 4.14m @ 17.9 g/t AuEq7, 9, and CBD102: 8.76m @ 8.05 g/t AuEq7,12, which is located approximately 350m north of the operating Cerro Bayo processing plant.
These results report to a newly defined mineralized zone located outside a previously interpreted Stockwork Vein domain of the existing maiden December 2020 Taitao Inferred Mineral Resource Estimate of 302koz AuEq6. The new results extend well beyond the limits of the 2020 MRE to the east and at depth (Figure 3 & 4).
The principal intercepts included12:
- 0.73m @ 31.71 g/t AuEq7 (16.97 g/t Au, 1105.1 g/t Ag) from 117.12m including 0.49 @ 46.67 AuEq7 (24.80 g/t Au, 1,640 g/t Ag) from 117.36m
- 3.60m @ 3.20 g/t AuEq7 (2.20 g/t Au, 74.77 g/t Ag) from 172.51m including 1.49 @ 7.00 AuEq7 (4.91 g/t Au, 157 g/t Ag) from 174.62m
- 7.5m @ 8.7 g/t AuEq7 (6.0 g/t Au, 206.3 g/t Ag) from 86.08m including: 2.47m @ 24.1 g/t AuEq7 (17.7 g/t Au, 483.9 g/t Ag) from 87.87m
- 8.76m @ 8.05 g/t AuEq7 (4.9 g/t Au, 237.4 g/t Ag) from 70.44m including: 1.25m @ 29.3 g/t AuEq7 (20.5 g/t Au, 667.0 g/t Ag) from 77.25m
- 29.91m @ 1.84 g/t AuEq7 (1.0 g/t Au, 63.5 g/t Ag) from 84.81m including: 8.0m @ 3.53 g/t AuEq7 (1.4 g/t Au, 162.7 g/t Ag) from 84.81m
- 1.46m @ 12.1 g/t AuEq7(6.46 g/t Au, 422 g/t Ag)from 83.99m
- 4.89m @ 8.5 g/t AuEq7 (4.31 g/t Au, 313.9 g/t Ag) from 101.57m including: 3.0m @ 12.81 AuEq7 (6.43 g/t Au, 478.4 g/t Ag) from 103.46m
- 7.44m @ 5.68 g/t AuEq7 (4.59 g/t Au, 81.57 g/t Ag) from 117.46m including: 2.23m @ 12.61 AuEq7 (10.34 g/t Au, 170.0 g/t Ag) from 119.88m
Drill intersections from progressively shallower, interpreted up-dip extensions of the higher-grade intercepts mentioned above, approximately 60m below and 80m to the east of the base of the Taitao open pit, include:
- 5.82m @ 4.38 g/t AuEq7 (1.76 g/t Au, 195.84 g/t Ag) from 60.53m including: 1.56m @ 5.9 g/t AuEq7 (2.6 g/t Au, 250.4 g/t Ag) from 63.66m
- 5.83m @ 3.16 g/t AuEq7 (1.43 g/t Au, 130.1 g/t Ag) from 58m including: 0.73m @ 13.24 g/t AuEq7 (4.73 g/t Au, 638.0 g/t Ag) from 60.34m
- 15.5m @ 3.32 g/t AuEq7 (2.97 g/t Au, 26.5 g/t Ag) from 114.38m including: 7.02m @ 5.2 g/t AuEq7 (4.27 g/t Au, 69.9 g/t Ag) from 114.38m
- 6.01m @ 6.89 g/t AuEq7 (5.62 g/t Au, 95.2 g/t Ag) from 140.91m including: 3.09m @ 9.6 g/t AuEq7 (9.05 g/t Au, 41.32 g/t Ag) from 140.91m
- 2.6m @ 9.2 g/t AuEq7(8.93 g/t Au, 19.95 g/t Ag) from 52.13m
- 2.61m @ 9.5 g/t AuEq7 (6.14 g/t Au, 249.7 g/t Ag) from 128.57m
- 2.71m @ 6.88 g/t AuEq7(4.56 g/t Au, 174.2 g/t Ag) from 205.61m
- 3.5m @ 2.9 g/t AuEq7 (2.0 g/t Au, 66.4 g/t Ag) from 44.98m including:0.93m @ 4.53 g/t AuEq7(4.17 g/t Au, 27 g/t Ag) from 47.52m
Deeper high-grade intercepts of breccia and stockwork veining related to the Appaloosa vein-breccia structure were reported from subsequent holes which returned results including:
- 1.76m @ 4.5 g/t AuEq7(1.87 g/t Au, 197.4 g/t Ag) from 246.35 including 0.54m @ 13.48 g/t AuEq7(5.05 g/t Au, 632 g/t Ag) from 247.57 m
- 0.47m @ 16.71 g/t AuEq7(13.1 g/t Au, 272 g/t Ag) from 260.74m
Encourgaing results have also been received for a newly discovered, steeply north easterly dipping high grade epithermal vein along an approximate 160m long horizontal extension representing a hangingwall splay adjacent to the Appaloosa fault-breccia.
- 1.95m @ 5.92 g/t AuEq7(3.73 g/t Au, 164.4 g/t Ag) from 170.93m including 0.94m @ 10.27 g/t AuEq7(6.5 g/t Au, 283 g/t Ag) from 170.93m
- 1.54m @ 8.32 g/t AuEq7 (3.80 g/t Au, 339.2 g/t Ag) from 109.2m including: 0.54m @ 37.68 g/t AuEq7 (8.1 g/t Au, 2221 g/t Ag) from 110.2m
- 1.43m @ 23.9 g/t AuEq7(19.0 g/t Au, 367.8 g/t Ag) from 140.55m including 0.55m @ 61.4 g/t AuEq7(48.9 g/t Au, 937 g/t Ag) from 140.55m
- 1.64m @ 6.83 g/t AuEq7(3.55 g/t Au, 245.9 g/t Ag) from 162.56m including 0.67m @ 13.32 g/t AuEq7(5.68 g/t Au, 573 g/t Ag) from 162.56m
These results collectively report to newly defined mineralized zones located within approximately 600m of the Cerro Bayo processing plant infrastructure. Importantly, these zones are located outside the dominantly Stockwork Vein domain component of the existing underground resource of the maiden December 2020 Taitao Inferred Mineral Resource estimate of 302koz AuEq16, and are considered to likely extend the potential of the MRE to the east and at depth.
Figure 3 – A-A´ Section view showing a summary of Equus drill results interpreted mineralisation and exploration targets along and at intersections of low and high angle splays along the Appaloosa Fault and Pegaso I-II zones
Figure 4 – Orthogonal view showing a summary of Equus and historic drill results, interpreted mineralisation and exploration targets along and at intersections of the Appaloosa Fault and Pegaso I-II zones
PEGASO VII TARGET- HISTORIC DRILL RESULTS
The Pegaso VII target is located 2.5km to the north-east of the Cerro Bayo plant infrastructure and sits 1km in a subparallel north west trend from the partially exploited Coyita Mine (approximately 140kOz AuEq1 @ 6.6 g/t AuEq1 in mine production/remaining NI 43.101 resources17) (Figure 5). Veining defined to date throughout the Pegaso VII Target predominantly occupies the footwall position with respect to the district scale, southeasterly dipping Appaloosa Fault (see Figure 5).
A total of 14,134.67m in 64 holes were drilled on the Pegaso VII target by previous operators, initiating in 2004 and for which the majority (>90%) was completed prior to 2013.
Historic drilling throughout the Pegaso VII target was broadly focused over a 450m wide x 1400m long corridor hosting a series of sub-vertical veins mapped and interpreted from core logging principally along, north-south and north-northwest trends (Figure 6). A large proportion of historic drilling was concentrated in the southern 400m of this corridor throughout which high-grade mineralization was intersected over a vertical interval of +250m (Refer to Section in Figure 7).
Significant drill results from the above historic drilling include18:
- 1.13m @ 166.06 g/t AuEq1 (95.51 g/t Au, 5291.05 g/t Ag) from 235.50m
- 1.70m @ 35.46 g/t AuEq1 (13.76 g/t Au, 1627.61 g/t Ag) from 259.10m
- 1.48m @ 39.00 g/t AuEq1 (5.55 g/t Au, 2508.95 g/t Ag) from 36.37m
- 1.00m @ 39.44 g/t AuEq1 (20.86 g/t Au, 1393.46 g/t Ag) from 169.15m
- 5.45m @ 5.13 g/t AuEq1 (4.53 g/t Au, 45.09 g/t Ag) from 322.30m
- 1.45m @ 9.41 g/t AuEq1 (2.04 g/t Au, 552.96 g/t Ag) from 127.00m
- 2.5m @ 5.36 g/t AuEq1 (1.78 g/t Au, 268.25 g/t Ag) from 129.80m
- 0.36m @ 30.55 g/t AuEq1 (10.01 g/t Au, 1540.64 g/t Ag) from 151.64
Importantly, 30 of the 64 historic holes drilled at Pegaso VII returned downhole intercepts of greater than 2.5 AuEq1 gram-metres19.
The above high-grade results generally correlate to weakly banded and brecciated individual veins of between 0.3-0.8m width which are commonly enveloped by zones of stockwork veining and brecciation varying in width between 1-5m.
Figure 5 – Plan view showing location of Pegaso VII, Appaloosa Fault vein-breccia and Pegaso II- VII targets and historic production/resources of the historic open pit and underground mines
Figure 6 – Pegaso VII Target – Plan view of southern portion showing summary high grade historic drill results and location of Section 4842820N (refer to Figure 3)
Figure 7 – Pegaso VII Section 4842820N – showing summary high grade historic composited drill results and unsampled drill core intervals (purple hole trace)
FOLLOW UP DRILLING
Planned follow-up drilling will test the geometry and continuity of high-grade mineralization over a vertical interval of +250m, both along strike and at depth, throughout a +400m long portion of the Pegaso VII vein corridor.
1 Gold Equivalent (AuEq) is based on the formula AuEq g/t = Au g/t + (Ag g/t / 75)
2 ASX Announcement 11 Oct 2021 – Equus Executes Option to Acquire Cerro Bayo & ASX Announcement 2nd Dec 2021 – Equus Acquires Cerro Bayo
3ASX Announcement 15 Apr 2021 Cerro Bayo Plant Back in Production
4 ASX Announcement-17th Oct 2022 Suspension of Processing, Cerro Bayo Project
5 ASX Announcement-17th Oct 2022 Suspension of Processing, Cerro Bayo Project
6 ASX Announcement – 22 Dec 2020 Maiden Inferred Mineral Resource Estimate, Cerro Bayo Project & Gold equivalent (AuEq) is based on the formula AuEq g/t = Au g/t + 0.0128 x Ag g/t
7 Gold Equivalent (AuEq) is based on the formula AuEq g/t = Au g/t + (Ag g/t / 75)
8 Based on Mandalay Resources Corporation, Cerro Bayo Mine NI 43-101 Technical Reports dated May 14, 2010. & March 21, 2017 Report #2699
9 ASX Announcement – 20th Jan 2022 Cerro Bayo Exploration Update
10 ASX Announcement – 26th July 2022 Cerro Bayo Update
11 Based on Mandalay Resources Corporation, Cerro Bayo Mine NI 43-101 Technical Reports dated May 14, 2010. & March 21, 2017 Report #2699
12 ASX Announcement -26 Jul 2022 Cerro Bayo Update
13 ASX Announcement -28 Oct 2022 Cerro Bayo Exploration Update
14 ASX Announcement – 30 September 2022 Quarterly Activities Report
15 ASX Announcement -30 Jan 2023 Cerro Bayo Exploration Update
16 ASX Announcement – 22nd Dec 2020 Maiden Inferred Resource Estimate at Cerro Bayo
17 Reported effective December 31, 2016 by Mandalay Resources Corporation – Cerro Bayo Project, Project #2559 according to Canadian Institute of Mining definitions in an independent National Instrument 43-101 Technical Report filed March 31, 2017.
18ASX Announcement -24 Feb 2023 Standout historic drill results at Cerro Bayo
19 The term gram-metre refers to the grams per tonne of gold equivalent , multiplied by the intersection length