Ranch Gold-Silver Project
The Ranch Project Is Located In The Prolific 'Golden Horseshoe’
The Ranch Property covers 178 km2 of highly prospective rocks in the northeastern region of the prolific metal-endowed Stikine Terrane, British Columbia, Canada. Magmatic events in Stikine during the Late Triassic and Early Jurassic were the driving source for the development of mineralizing porphyry and epithermal systems. On both the east and west sides of the Bowser Basin the same magmatic and mineralizing events are recognized (Logan and Mihalynuk, 2014), forming an arch of gold and polymetallic mineralization; which is depicted herein as the 'Golden Horseshoe' which includes the Golden Triangle (Figure 1).
The Ranch Project straddles a key stratigraphic horizon between rocks of the Upper Triassic Stuhini Group and Lower Jurassic Toodoggone Formation. The boundary between these units delineates a major geological unconformity with a regional significance demonstrated by the many deposits concentrated along its extent within the Golden Horseshoe. The project is also located within the historic Toodoggone region, a proven and profitable mining jurisdiction that is host to multiple copper-gold porphyry and high grade gold-silver deposits that includes the Kemess gold-copper mine only 60 km to the southeast (Figure 2). The Golden Horseshoe concept provides a visual context for the mines, discoveries and common geology that extends from the Golden Triangle to Toodoggone regions, forming a prolific metalliferous arch that encompasses the Quesnel and Stikine terranes.
Exploration on the Ranch property and surrounding area began in the early 1970s, followed by extensive exploration throughout the 1980s that identified numerous showings, prospects, and deposits. This activity culminated in 1991 with surface mining of the prospective Bonanza, Thesis III, and BV Zones that produced 10,000 oz gold over a 1-year period. None of these prospective zones were ever developed beyond shallow surface pits that were later backfilled. The surrounding areas were never systematically explored for gold-silver mineralization, with a significant amount of historic drilling being largely restricted to testing identified surface exposures of mineralization. With previous exploration the Ranch property contains a number of key assets for rapid development, including 34,117 metres of diamond drilling and road accessibility from the southeast.
1980 vs 2020
At the heart of the Ranch Trend are 21 zones of structurally controlled gold mineralization over a 25 km2 area. Surface expression of the mineralization is coincident with pervasive argillic and silica alteration, large gold and silver-in-soil anomalies, and anomalous rock and trench results.
On the Ranch property significant gold and silver mineralization occurs with silicification flanked by widespread argillically altered zones, associated with a high-sulphidation epithermal system (Figure 3). Historic production is minimal, consisting of three small pits where surface mining in 1986 and 1991 processed a total of 41,209 tonnes of high-grade surface ore from the Bonanza, Thesis III, and BV Zones. The regional along-strike extent of all 21 zones of gold mineralization largely remains open and untested, as historic drilling concentrated on targeting only known high-grade zones of this large epithermal system.
By combining historic data with recently acquired geological data and modern reinterpretation there is significant potential to add gold and silver ounces across the entire mineralizing system. Re-analysis of historic drill results is providing context to previously unrecognized bulk-tonnage potential with near-surface intercepts enveloping higher-grade intervals of gold and silver mineralization. These results occur within the footprint of the historically surface mined areas, but also include significant gold-silver intercepts along strike and at depth.
Historic High-Grade Intercepts
Select historic high-grade intercepts from concentrated drilling at the Bonanza, Thesis III, Thesis II, and BV Zones includes:
|ZONE||High-Grade Intercepts||Bulk-Tonnage Intercepts|
|BONANZA||25.9 g/t Au over 19.40 m||6.58 g/t Au over 78.27 m|
|29.9 g/t Au over 25.60 m||14.42 g/t Au over 49.11 m|
|THESIS III||26.48 g/t Au over 11.00 m||7.20 g/t Au over 48.30 m|
|16.39 g/t Au over 8.26 m||4.94 g/t Au over 39.98 m|
|THESIS II||9.78 g/t Au over 7.00 m||2.36 g/t Au over 49.12 m|
|5.12 g/t Au over 6.51 m||2.15 g/t Au over 36.27 m|
|BV||39.83 g/t Au over 4.00 m||7.15 g/t Au over 24.00 m|
|8.11 g/t Au over 10.30 m||3.51 g/t Au over 28.01 m|
** Based on limited information parts of the surface exposures of the above results have potentially been surface mined. However, both high-grade and bulk-tonnage drill intercepts and surface mineralization extend beyond the known surface pits and the system remains open along strike and at depth.
The Ranch property is predominantly underlain by flat-lying to gently west-dipping volcanic and sedimentary strata of the Lower Jurassic Toodoggone Formation (Figure 3), part of the Hazelton Group that is exposed throughout the prolific metal-endowed Stikine Terrane. The Toodoggone Formation can be divided into upper and lower volcanic cycles as illustrated on the simplified stratigraphic column in Figure 4. The Ranch property is predominantly underlain by thick sequences (>300 m) of andesitic tuffs and flows belonging to the lower volcanic rock cycle. These volcanic strata erupted concurrently with the development of deeply rooted faults that focused both magmatism and mineralization (Figure 3). Magmatism occurs as local dike intrusions that share a similar composition to the host volcanic units and represent potential feeder systems. Felsic dikes and irregular bodies of dacitic to rhyolitic composition have also been encountered in drill holes and are thought to be genetically linked to late-stage ore-forming fluids. Similar relationships are often observed in the southern Toodoggone spatially associated with porphyry style mineralization, including at Kemess.
Localized conglomerates and volcaniclastics within the lower cycle are confined within blocks dropped by steeply dipping syn-volcanic faults and can potentially be used as a vector towards epithermal mineralization.
Figure #4 – Simplified stratigraphic section for the Ranch project and the broader Toodoggone region. The different types of intrusive rocks, mineralization, and the time period for which they span is illustrated on the right side of the diagram.
The Ranch property has undergone a relatively simple brittle deformation history of syn-volcanic graben development and subsequent strike-slip deformation. The most dominant structural features on the property are a series of well-developed steeply dipping NW-NNW (320-350°) striking faults. They typically show evidence of normal displacement to the NE and SW with localized, late, strike-slip reactivation. These are the oldest structures on the property and represent syn-volcanic growth faults that formed during Lower Jurassic extension and block faulting.
The orientation and characteristics of the mineralized zones within the Ranch Trend are consistent with the development of robust hydrothermal systems within a pre-existing NW-NNW trending fault and fracture system. This system is likely reflecting the original volcanic basin geometry with these structures acting as conduits for fluids to migrate and precipitate metals. The NW structures and associated mineralization are locally offset by SW-NE trending strike-slip faults with minimal lateral displacement. The structural relationships observed in outcrop and drill core are also observed in the magnetic data, providing numerous new exploration targets.
Alteration and Mineralization
Widespread argillization and silicification of volcanic strata is found throughout the Ranch property, with important alteration assemblages including alunite-quartz, hematite-illite-quartz, dickite-quartz, quartz-barite and quartz-pyrite. These alteration patterns work inwards and downwards in a typical, zoned epithermal alteration system, with all significant gold mineralization occurring within silica-sulphate and silica-sulphide bodies flanked by argillically altered zones. On surface, zones of argillic alteration weather recessively and are typically obscured by alpine vegetation or underlie linear swamps. Where exposed on surface, they comprise strongly limonite and jarosite-stained argillic and lesser vuggy silica altered felsenmeer. The variation and zonation of alteration on the Ranch property suggests that epithermal mineralization was part of a large-scale hydrothermal system.