Discovery of a Cu-Au porphyry system at Come By Chance (CBC)

Situated in the prolific copper-gold porphyry belt of British Columbia

B.C. Porphyry Belt

BC-copper-gold-porphyries

Over 80% of the world’s copper production comes from large-scale open-pit porphyry copper mines.

In Canada, British Columbia enjoys the lion’s share of porphyry copper/ gold mineralization.

These deposits contain the largest resources of copper and 50% of the gold in the province.

The Prolific Greenwood Mining District

Belmont Resources B.C. Projects

The prolific Greenwood mining camp of southern British Columbia is considered to be one of the most concentrated mineralized areas in western North America with over 30 past producing mines, each only scratching the surface.

B.C. Porphyry Belt

CBC-Rocks-over-LIDAR

High-gold and copper values at surface are indication of rising hydrothermal fluids via structures/fractures from a concealed mineral-bearing intrusive.

Crook Lake Caldera is an indicated collapsed breccia, an ideal location for the deposition of circulating mineral-bearing hydrothermal fluids.

Classic Copper-Gold Porphyry Geophysical Signatures

Airborne Magnetics – RTP

CBC_DRILL-OVER-MAG-w-Section

A magnetic low anomaly surrounded by a magnetic high anomaly in a copper-gold porphyry system is an important exploration tool because it reflects the zoned nature of alteration and mineralization in these systems. The magnetic low often corresponds to the intensely altered and mineralized core of the system, where magnetite has been destroyed, while the magnetic high corresponds to the outer, less altered zones where magnetite is preserved. This pattern is a strong indication of a porphyry system.

IP – Resistivity

CBC DRILL-OVER-RESISTIVITY-w-Section

High-grade cores of porphyry copper systems often contain copper sulfide vein networks with approximately 1-3% copper sulfides, which are highly conductive (resistivity low).

IP – Chargeability

CBC-DRILL-OVER-CHARGE

 Surrounding this core is a chargeable halo with up to 10% disseminated pyrite. This pyrite halo encircles the porphyry core and consists of 5-15% pyrite.

2022 Drilling Intercepts Extensive Propylitic Alteration  ‘Halo of Porphyry’

Alteration Zoning provides clues to hidden ore bodies.

Provides Vectors Towards Potential Porphry Core

  • Copper-gold porphyry deposits are generally characterized by an association with porphyritic intrusions, by overprinting Propylitic, Phyllic and Potassic alteration.
  • Propylitic alteration, characterized by the occurrence of chlorite and epidote, is typically the most extensive and peripheral alteration facies developed around porphyry ore deposits.
  • Belmont’s CBC copper-gold porphyry target has all the key elements enabling it to vector towards the core of a potentially large porphyry system.
idealized-alteration-zoning of porphyry

Cross section of porphyry copper deposit showing idealized alteration zoning (after Lowel and Guilbert, 1970)

All six drill holes encountered extensive Propylitic Alteration

CBC- 2022Drill area zoom
CBC 2022-drilling-alteration
  • The 2022 -2,304 meter drill program focused on the south west area of the property. Drilling confirmed porphyry style alteration, veining and mineralization over an initial area measuring 1,300 meters by 900 meters.
  • Extensive Propylitic (chlorite, epidote & serecite) alteration encountered in all six drill holes.
  • In a copper-gold porphyry system, propylitic alteration represents one of the outermost alteration zones, typically surrounding the more economically significant potassic and phyllic zones closer to the core of the deposit. 

All six drill holes encountered extensive Pyrite Mineralization

CBC- 2022 Drill area zoom over Chargeability
CBC 2022-drilling-pyrite
  • Pyrite, which is reflected by high chargeability,  is commonly associated with the outer zones of porphyry systems, particularly in propylitic alteration, where it can form extensive halos around the more mineralized cores. These halos can act as geochemical guides during exploration. Elevated pyrite content in the propylitic zone can often be used to trace back toward more copper- and gold-rich areas, which are typically found in the phyllic and potassic zones closer to the system’s center.

All six drill holes encountered extensive Quartz Veining

CBC- 2022 Drill area zoom over Chargeability
2022-drilling-Qtz-veins
  • The presence of extensive quartz veining in the propylitic zone is important for several reasons:
  • Quartz veining, which is reflected by high chargeability, often indicates the presence of fluid pathways through which hydrothermal fluids traveled during the formation of the porphyry system. These veins can show that the propylitic zone has been affected by hydrothermal processes, even though it’s farther from the deposit’s center. The fluids responsible for the alteration may have carried metals or other elements that were deposited in more central zones.
  • Quartz veining in the propylitic zones  typically carry only minor quantities of copper and gold  compared to the inner alteration zones (potassic and phyllic),

Minimal copper gold intercepted in outer Propylitic halo which is expected in a porphyry zonation

CBC- 2022 Drill area zoom over Resistivity
CBC 2022-drilling-CuEQ
  • Copper and gold mineralization is typically associated mainly with the Potassic and Phyllic alteration zones of the porphyry system with the peripheral Propylitic alteration zone being more distal from the porphyry core containing less copper and gold.

Summary

2022 drilling results were highly encouraging in that the results, in combination with the geophysical interpretations, are interpreted to be the alteration “halo” around a large intrusive centre.

All the data to date has provided important vectors pointing to the potential core of the copper-gold porphyry system.

CBC-Propylitic Zone
idealized-alteration-zoning of porphyry

Planned drilling will focus primarily on vectoring to the central porphyry potassic core in the search for a
mineralised porphyry Cu-Au intrusion.

Airborne Magnetics – RTP

CBC-planned-drill-over-mag

IP – Resistivity

CBC-Planed-Drill-over-Res

IP – Chargeability

CBC-Planned-drill-over-charge