JOHANNESBURG (miningweekly.com) - Canadian mineral exploration and development company Ivanhoe Mines has completed an independently verified and updated mineral resource estimate for the ultra-high-grade Kakula discovery at the Kamoa-Kakula copper project, near the mining centre of Kolwezi, in the Democratic Republic of Congo (DRC).

The tier-one Kamoa-Kakula project is a joint venture between Ivanhoe Mines, Zijin Mining and the government of the DRC.

The updated mineral resource estimate, prepared under the direction of independent consultant Amec Foster Wheeler, covers a mineralised strike length of 13.3 km. For the first time, the updated estimate incorporates mineral resources contained in the Kakula West discovery area and the saddle area between the main Kakula discovery area and Kakula West.

The new estimate boosts the total tonnage of Kakula's indicated mineral resource by 50%, at a 3% copper cut-off, compared with the previous resource estimate issued in May 2017 that covered a strike length of 7.7 km.

Kakula's new indicated mineral resources, at a 3% cut-off grade, have increased by 58-million tonnes to 174-million tonnes at a grade of 5.62% copper.

The Kakula high-grade mineralised trend remains open in multiple directions. Ivanhoe executive chairperson Robert Friedland said Ivanhoe expects ongoing in-fill and step-out drilling will yield significant expansions and further upgrades to the current resources.

"Kakula is the most remarkable mineral discovery we have seen during our 35-plus years in the exploration industry. The new, independently-verified resource estimate now places Kamoa-Kakula ahead of Indonesia's renowned Grasberg deposit as the world's fourth-largest copper discovery on the planet in terms of contained copper. And it still is growing."

He added that the exceptionally high copper grades, thicknesses and continuity of the mineralisation at Kakula distinguish this discovery from anything else in the Central African Copperbelt.

"Based on the findings of the independent preliminary economic assessment completed in November of last year, the resources we've discovered should allow us to build a world-scale, highly-mechanised, underground copper mine with an initial capital cost expected to be far lower than [that of] other operations of this size," he further elaborated.

With this initial mineral Resource estimate at Kakula West, he notes that the company can begin to evaluate technical and infrastructure options to expeditiously develop the zones of thick, high-grade, bottom-loaded chalcocite in this latest discovery area.

Friedland said a development scenario using a mining rate of six-million-tonnes a year and a copper cut-off grade of 3% indicates that Kakula already has enough indicated mineral resources to mine at an average grade of between 5.5% and 6% copper for about 30 years.

"If we lower the copper cut-off grade to 1%, which is higher than the mining grades at most of the world's major copper mines, we could be mining almost 3% copper at Kakula for approximately 100 years," Friedland said.

However, he adds that the western trend of Kakula's high-grade mineralised core appears to be open to the southwest, suggesting that potential extensions of the Kakula West discovery could remain within the Kamoa-Kakula mining licence for a considerable distance.

The ongoing gravity and geophysical seismic surveys will provide the Ivanhoe geological team with additional data to better assess the direction and extent of Kakula's high-grade mineralised zone, he averred.

"The unparalleled strength and continuity of the Kakula mineralised trend also bodes well for the potential for exploration success on Ivanhoe's 100%-owned Western Foreland licences, to the west of Kamoa-Kakula."

Given the accumulation of in-depth, proprietary geological insights gained by Ivanhoe's geological team into the features controlling the high-grade copper mineralisation during almost two decades of exploration in the region, the company is highly confident of further exploration successes this year and beyond.

The Kakula discovery is about 10 km southwest of Kamoa's initial Kansoko Mine development, with Ivanhoe and Zijin having been conducting an aggressive drilling programme totalling more than 181 500 metres at the Kakula discovery since April 2016.

The programme is expected to continue through 2018.