Ivanhoe Mines Ltd. on Jan. 23 said recent step-out drilling extended the length of the Kakula copper discovery by approximately 1.6 kilometers, or 40%, to about 5.5 kilometers.
The Kakula deposit, which forms part of the company's Kamoa-Kakula joint venture property in the Democratic Republic of the Congo, remains open along strike.
Ivanhoe Mines and Zijin Mining Group Co. Ltd. each hold an indirect 39.6% interest in the property, while Crystal River Global Ltd. has an indirect 0.8% interest and the DRC government has a direct 20% interest. Ivanhoe acts as project operator.
Assay results from 25 drill holes completed as part of an ongoing campaign returned highlights including 11.10 meters, true width, grading 5.82% copper, using a 3.0% copper cutoff grade, 1.6 kilometers northwest of Kakula's current resource.
"It is remarkable to drill a step-out hole more than 1.6 kilometers beyond the limits of the previous mineral resource boundary and intersect almost identical, high-grade, chalcocite-rich mineralization," Robert Friedland, Ivanhoe's executive chairman, said in a statement.
Ivanhoe reported that drilling 400 meters southeast of the Kakula deposit also intersected similar chalcocite mineralization, returning 3.51 meters grading 3.63% copper.
The company and Zijin Mining mobilized additional drill rigs to Kakula to accelerate exploration, with nine rigs now drilling on the deposit. Drilling efforts include a focus on expanding resources to the northwest, infill drilling in the central area of the deposit and step-out drilling to the southeast.
An updated resource estimate for the Kakula deposit is anticipated early in the second quarter. An initial estimate was completed in October 2016.
Ivanhoe also reported that an expanded preliminary economic assessment is underway, investigating the potential of a combined mining operation on the Kamoa and Kakula deposits with mining rates ranging between 8 million tonnes per annum and 16 Mtpa.
A December 2016 preliminary economic assessment outlined two development options for the Kamoa-Kakula property, with a single-mine option comprising Kakula starting production at a rate of 4 Mtpa and a two-mine option with a production rate of 8 Mtpa.