Ivanhoe announces more high-grade copper results from Kakula discovery

JOHANNESBURG (miningweekly.com) – The 2016 drilling campaign at Ivanhoe Mines’ Kakula discovery, in the Democratic Republic of Congo, is continuing to demonstrate that it is substantially richer, thicker and more consistent than other mineralisation at the Kamoa project.

The Kamoa project is a joint venture between Ivanhoe Mines and Chinese miner Zijin Mining.
“Given the consistent and thick intercepts at shallow depths of very high-grade copper mineralisation, Kakula is quickly becoming a key focus in our planning for the development of the Kamoa project,” CEO Lars-Eric Johansson said in a statement on Friday.

The company noted that Kakula’s copper mineralisation was consistently bottom-loaded and chalcocite dominant.

The consistent, bottom-loaded nature of Kakula mineralisation supports the creation of selective mineralised zones at cutoffs of between 1.0% and 3.0% copper, and potentially higher.
The Kakula copper mineralisation displays vertical mineral zonation from chalcopyrite to bornite to chalcocite, with the highest copper grades associated with the siltstone unit consistently characterised by chalcocite-dominant mineralisation.

Chalcocite is a high-tenor mineral that is opaque and dark-gray to black with a metallic lustre.
Owing to its very high percentage of contained copper by weight and its capacity to produce a clean, high-grade concentrate, chalcocite is considered to be the most valuable copper mineral.
The Kakula discovery remains open along a northwesterly-southeasterly strike, while high-grade copper mineralisation has been outlined along a corridor that is now at least 3.5 km in length.

The high-grade copper zone is less than 300 m below surface in the central section and gently dips to the south-east and north-west.

Initial metallurgical test results received in July from a sample of drill core from the Kakula discovery zone showed copper recoveries of 86% and produced a copper concentrate with an extremely high grade of 53% copper.

The July results also indicated that material from Kamoa's Kakula and Kansoko zones could be processed through the same concentrator plant, which would yield significant operational and economic efficiencies.

Earlier metallurgical testwork had indicated that the Kamoa concentrates contain arsenic levels of 0.02%, which are extremely low by world standards.

Given this critical competitive marketing advantage, Kamoa's concentrates are expected to attract a significant premium from copper concentrate traders for use in blending with concentrates from other mines.

The Kamoa concentrates will help to enable high-arsenic concentrates from mines in Chile and elsewhere to meet the limit of 0.5% arsenic imposed by Chinese smelters to meet China's new environmental restrictions.