Summary:
The Revel Ridge Property lies within the Selkirk Mountains near the north end of the Kootenay Arc, a complex sequence of east dipping Neoproterozoic to Lower Paleozoic metasedimentary and metavolcanic miogeosynclinal rocks. The Kootenay Arc is characterized by tight to isoclinal folds and generally west verging thrust faults with greenschist grade regional metamorphism. The Revel Ridge Property is underlain by north to northwest-striking, moderate to steeply east-dipping metasedimentary and metavolcanic rocks of the Hamill and Lardeau Group and Badshot and Mohican Formation rocks. Gold mineralization at Revel Ridge is spatially related to a property scale, ductile deformation zone which ranges in width from approximately 5- 25 m and which has a strike length exceeding 5 km: The MDZ forms approximately 500 m into rocks of the hanging wall of the Akolkolex Thrust, which is an arc parallel regional scale thrust. Formation of the mineralized deformation zone may in part be related to the development of the larger regional scale thrust.
The RRMZ is the principal mineralized zone hosted within the MDZ which is considered to be a structurally controlled orogenic gold-polymetallic deposit. The RRMZ is a sheet-like tabular sulphide vein system hosted in a large planer deformation zone composed of banded massive and stringer arsenopyrite-pyrite-sphalerite-galena mineralization with appreciable content of gold and silver. The RRMZ has been traced on surface by drilling, geological mapping and soil geochemistry for a minimum strike length of 5.7 km and on-strike mineral showings occur along a structural trend up to approximately 8 km long. Concentrated drilling has intersected the RRMZ over a 2,200 m strike-length and at least 1,175 m in down-dip extent. The RRMZ generally dips approximately 55° to 60° to the northeast with an average true thickness of 2.5 m, but it may exceed 15 m locally in true thickness and has the potential to be expanded beyond the current drilled limits.
The silver-lead-zinc-rich RRYZ is considered to be a silver-zinc rich carbonate hosted replacement deposit composed of multiple parallel siliceous sphalerite-galena-bearing zones. The individual zones making up the RRYZ occur as lenticular bodies within silicified and marbleized limestone horizons. In comparison to the RRMZ, the RRYZ tends to have shorter strike lengths and shorter down dip lengths in the range of 500 m of strike and 200 m downdip. The zones may demonstrate periodicity with mineralization re-starting at permissive lithologic and structural points and potentially folded repetitions of carbonate stratigraphy.
Mineralization
At Revel Ridge, two main styles of mineralization have been documented: (1) a structurally controlled orogenic goldpolymetallic deposit; and (2) a silver-zinc rich carbonate hosted replacement deposit. The bulk of the economic resource within this deposit is hosted by the orogenic gold-polymetallic deposit, or the RRMZ.
Additional mineralized zones are principally mineralogic and spatial variations on the RRMZ, namely the RRHZ, RRFZ and RR28Z. Significant differences in mineralogy and deformational history suggests that the carbonate hosted silver-zinc-lead rich RRYZ did not developed contemporaneously with the RRMZ. Both the RRMZ and RRYZ have significant potential for expansion.
Revel Ridge Main Deformation Zone
The RRMZ is a structurally controlled orogenic precious and polymetallic (Au-Ag-Pb-Zn-As) deposit. The deformation zone that hosts the RRMZ has been traced along strike for >8 km and down-dip for at least 1,200 m. The deformation zone is effectively a mylonitic shear zone with a dominantly reverse and sinistral movement history. The zone has an average dip direction of 052°/58°. Mineralization occurs over an average true width of approximately 2.5 m.
Three styles of mineralization are associated with the RRMZ:
1. Early mineral quartz veins. Both in drill core and in underground workings, white quartz veins locally containing moderately coarse-grained black sphalerite occur throughout the Revel Ridge Mine area. The veins appear to boudinaged and embayed into fine-grained massive sulphide bands and appear to pre-date them. These veins range from a few centimetres up to 1.0 m in true width.
2. Syn-mineral banded massive to semi-massive sulphides – main stage mineralization. Massive sulphide bands consisting of compact grains of arsenopyrite, red-brown sphalerite, pyrite and minor galena form the dominant sulphide phases and are one of the principal hosts to gold mineralization, and higher-grade gold mineralization. Massive sulphide bands range from a few centimetres to decimetre wide and may continue for tens of metres unabated. The bands are commonly best developed at or near major lithologic changes, including quartzite-limestone contacts and quartzite-phyllite contacts. 3. Sheeted quartz – sulphide veins and veinlets. Narrow, cm- to mm-scale quartz-sulphide veinlets are noted throughout the RRMZ. These veinlets formed parallel to the dominant shear fabric and may contain sphalerite, arsenopyrite and pyrite along their margins. These veins and veinlets may carry significant base and precious metals and serve to increase the width of mineralized zones beyond that which would solely be accounted for by massive sulphide veins and replacements.
Deposit Types
The Revel Ridge Property area contains two distinctly different styles of mineralization: (1) highly planar, arsenical- and Au-rich, structurally controlled polymetallic sulphide zones and with no definitive host rock association, exemplified by the RRMZ; and two Ag-Zn-Pb deposits hosted only in marbleized and silicified limestone units, exemplified by the RRYZ.
RRMZ – Structurally Controlled Orogenic Au Deposit
Most of the Revel Ridge technical data suggests that the RRMZ is an orogenic Au deposit. Using the model developed Groves et al. (1998) and summarized by Sillitoe (2020), orogenic Au deposits are characterized globally by:
• Formation in the late stages of regional scale orogenic events.
• Commonly hosted in accretionary or collisional orogens at relatively deep paleo-depths of 5 km to 20 km below surface.
• Association with low salinity, Au- and arsenic-bearing fluids generated during the transition from the greenschist to amphibolite metamorphic grades.
• Productive mineralized zones forming over very significant vertical distances, potentially exceeding 2.0 km; and
• Association with the dilatant points of deep structural zones within segments of orogen-parallel, deep crustal faults (Sillitoe, 2020).
RRYZ Ag-Pb-Zn Occurrence – Deposit Model
At Revel Ridge, the second style of mineralization is associated with Ag enriched Zn-Pb deposits. Two deposit models have been used to describe Pb-Zn deposits in the northwestern portions of the Kootenay Arc, such as: (1) Shuswap Metamorphic Complex Pb-Zn Deposits; and (2) Kootenay Arc Carbonate Replacement Deposits.