Continental Gold Inc. (TSX:CNL; OTCQX:CGOOF) has commenced drilling a deep diamond drill hole from the Higabra tunnel elevation at its Buriticá project in Antioquia, Colombia. The planned 1,600-meter hole has been designed to test for gold and copper mineralization within a known porphyry intrusive body located in the footwall of the Veta Sur vein system and along the western extension of the Yaraguá vein system. This hole will also test the depth extensions of both high-grade vein systems.
The company currently has 11 diamond drill rigs operating presently as part of its 73,500-meter definition and exploration drill program for 2019. Construction of the Buriticá project remains on schedule for first gold pour in H1 2020.
Continental Gold continues to advance with construction on or ahead of schedule. While the company previously stated that mechanical construction would be complete in the first half of 2020, it now says that the construction will be complete in the first quarter of 2020, then commercial production commencing another 6 to 9 months after completion.
Highlights (see below graphics)
- The planned 1,600-meter diamond drill hole will be the deepest one drilled to date at the Buriticá project and will span a final vertical depth of more than 2,000 meters below surface. The hole is collared at the Higabra tunnel elevation (up to 700 meters below surface) and is targeting the depth extensions of both the Yaraguá and Veta Sur high-grade vein systems as well as the final target, the gold-copper porphyry intrusive. Results from the drill hole are anticipated in Q4 2019.
- The new drill hole has the potential to extend the high-grade vein mineralization by more than 400 meters vertically from the deepest intercept drilled to date, as well as extend the porphyry mineralization by greater than 700 vertical meters.
- A two-year program—involving extensive core relogging and reinterpretation of the geology of the Buriticá deposit—highlights that the high-grade gold-carbonate-base metal (“CBM”) veins at Buriticá are formed by a gold-bearing porphyry intrusive system (see Figure 2). The Yaraguá veins are located within a porphyry intrusive complex (herein referred to as the Buriticá Intrusive Complex (“BIC”) and the Veta Sur veins occur along the contact zone between the BIC and the surrounding country rock.
- The BIC displays alteration mineralogy and metal zonation which is typical of gold-dominant porphyry deposits. The copper-to-zinc ratio increases with depth and is associated with changing alteration patterns indicating progressively higher temperatures of formation. This is reflected by a change in alteration mineralogy from sericite / chlorite / pyrite to magnetite / biotite / pyrrhotite at depth.
- The deeper part of the BIC is associated with a Quartz Feldspar Porphyry (“Porphyry”) which is coincident with a strongly magnetic body as defined by modelling of the airborne geophysical data and magnetic susceptibility data collected in the drill holes (see Figure 1). Previous exploration drilling into the Porphyry was confined only to the top of the magnetic body due to steep topography and a lack of underground development limiting access for drill rigs and returned multiple thick intercepts including:
- 65.1 meters @ 10.42 g/t gold and 8.8 g/t silver (BUSY291)
- 26.45 meters @ 2.61 g/t gold and 2.74 g/t silver (BUUY291D04)
- 27 meters @ 2.28 g/t gold, 19.2 g/t Silver and 0.1% of Copper (BUUY339D02)
The modelled magnetic data widens and intensifies as it progresses vertically, indicating that the Porphyry mineralization potentially extends considerably deeper.
With more than 18 kilometers of commercial-scale underground development now in place and advancing at more than 1 kilometer per month, drilling access has materially improved.
“The company has been waiting a long time for underground development to advance to the point that a suitable location for a drilling chamber could be established in order to drill-test the depths of the vein and the potential porphyry feeder systems,” said Continental Gold CEO Ari Sussman.
David Reading, Special Advisor to Continental Gold, stated: “Buriticá is clearly analogous to the famous Porgera mine in Papua New Guinea and demonstrates a clear genetic relationship between high-grade carbonate base metal (“CBM”) veins and an underlying potassic altered porphyry. The target is very tangible as we have already drilled into the top of this body and intersected high gold grades for a porphyry deposit. We are very excited for this new hole as it has been designed to target the core of the porphyry intrusion body at depth.”
All images courtesy of Continental Gold