The Chochi zone is hosted by intermediate volcanic rocks, probably of Devonian age (Stikine Assemblage) and dioritic phases of the Late Devonian McLymont Plutonic Suite (equivalent to Forrest Kerr Plutonic Suite(?)). The area is a local focus of alteration, with coincident potassium-feldspar, white mica, epidote, and chlorite. Although alteration is patchy, it is generally elongate in a northeast orientation, with epidote and potassium-feldspar coalescing into more coherent bodies near the toe of the local glacier. White mica alteration is structurally controlled, forming narrow zones of northeast oriented alteration.

A 350 by 450 metre zone of greater than 0.5 per cent pyrite is present with minor chalcopyrite and is focused in the eastern portion of the showing. Chalcopyrite is most abundant towards the southeast, indicating a vector towards the glacier. Gold mineralization also increases to the southeast, with values of 0.1 to 1.0 grams per tonne reported coincident with the chalcopyrite zone (Assessment Report 39128).

Copper-gold mineralization occurs as clots, stringers and very finely disseminated chalcopyrite, pyrite and bornite associated with an intense potassic alteration assemblage of fine, ‘shreddy’ secondary biotite with veins and dikelets of pink potassium feldspar. Alteration and mineralization overprint and crosscut primary textures within the diorite and are thought to be related to a later phase of magmatism.

The copper-gold mineralization, although variable in intensity, was observed over an area of 1.5 kilometres. The most consistent mineralization was traced for over 600 metres along a west-northwest trend in rugged, glacially polished outcrops before disappearing under an extensive cover of glacial debris to the northwest and under a large glacier to the southeast. The most intensely mineralized zone observed is reported to be approximately 150 by 220 metres in size and is the area from which most of the preliminary sampling was carried out. Copper mineralization is pervasive in the vicinity of the Chochi Zone. Pendants of sedimentary rocks within the pluton are mineralized with chalcopyrite, malachite, azurite, and pyrite within and adjacent to the larger zone of copper-gold mineralization.

Romios Gold Resources discovered the zone in 2007 and collected a total of 19 chip-channel and rock-grab samples randomly over the intensely mineralized area. A single grab sample (686577) assayed 2.61 per cent copper and 0.8 gram per tonne gold (Assessment Report 30449). Chip-channel samples were collected across one metre of exposed bedrock, generally perpendicular to foliation where present. Assays for 1 metre chip-channel samples ranged up to 0.5 per cent copper and 0.159 gram per tonne gold (Assessment Report 30449).

In 2019, Crystal Lake Mining collected a heavily weathered, grey-brown sample of sericite and quartz altered, intermediate, volcanic rock hosting, minor chalcopyrite, and pyrite with malachite staining. Ankerite veins occur in the area, with massive graphite banded within. The sample assayed 0.03 gram per tonne gold, 14.46 grams per tonne silver, 0.28 per cent copper, 41.3 parts per million nickel, and 16.9 parts per million cobalt (Sample A0039487, Assessment Report 39128).

In 2019, Crystal Lake Mining (later changed to Enduro Metals Corporation) collected 2070 rock samples and 6125 hyperspectral measurements were collected throughout the Newmont Lake property. In total, 714 rock samples and 1480 hyperspectral measurements were collected from Chachi corridor alone. The area was also extensively covered by the property-wide soil sampling program. A total of 2624 soils samples were collected from the property, with a main focus around the Chachi Corridor, Cuba, North/Kerr Glacier, and Thumper areas. In addition to geological and geochemical work, approximately 18 line-kilometres of an Induced Polarization (IP) survey was completed along the northern portion of the west side of the Chachi corridor over known showings that included QS (104B 446), Tetra (104B 448), Chochi (104B 461), Tic 5 (104B 549), Leo (104B 717), Brass Rose (104B 723) and Grey Rose (104B 728).

In late 2019, Crystal Lake Mining Corporation announced the discovery of a new multi-element hydrothermal system in the Chachi Corridor (“Chachi”) containing high-grade gold, silver, copper, nickel, cobalt, zinc and lead mineralization spread over an 8 kilometre long by 4 kilometre wide area along the eastern side of the McLymont Fault. The fault separates the Chachi Corridor on the east from the “Newmont Lake Gold Corridor” on the west. The Chachi Corridor includes a variety of notable MINFILE occurrences including: QS (104B 446), Tetra (104B 448), BC (104B 450), Everest (104B 451), North Ridge (104B 452), Chochi (104B 461), Tic 5 (104B 549), RNT (104B 550). The 2019 exploration efforts led to the discovery of several new mineral occurrences: Leo (104B 717), Brass Rose (104B 723), Grey Rose (104B 728), Artemis (104B NEW), Flying Dutchman (104B NEW) and Silver Rose (104B NEW).

The 2019 mapping of the Chachi Corridor was the most comprehensive this area has seen to date. It defines a multiphase intrusion which ranges from dioritic to granitic in composition, with several distinct textural variations. In many areas, the geology could be simplified to an intrusive breccia, with the granitic phase cutting the dioritic ones. Overall, the Chachi Corridor displays various fault blocks containing intrusions of the Forrest Kerr and McLymont Plutonic suites (which (in this area) appear to be equivalent intrusions). Most of the mineralization in the Chachi Corridor is vein hosted. Different alteration and mineralization styles throughout the Chachi Corridor suggests that porphyry like zonation may be present. A central porphyry domain could be focused at the Chochi and RNT occurrences, extending east beneath glacial cover. It remains unclear how the nickel-cobalt arsenide veins fit into the interpretation. Multiple samples from at least three different styles of mineralization over the Chachi Corridor have yielded assays (in-situ grab and chip samples from outcrop) ranging up to 21.03 grams per tonne gold, 2,350 grams per tonne silver, 5.4 per cent copper, 7.7 per cent nickel, 0.85 per cent cobalt, 15.2 per cent zinc and 6.2 per cent lead (Crystal Lake Mining Corp., News Release, Oct.10, 2019).

See Northwest (104B 281) for a general summary of the Newmont Lake property work history. See Cuba North (104B 440) and Cuba South (104B 334) for related details.