Ivanhoe Mines Ltd. unveiled a 50% surge in indicated resources at the Kakula deposit, part of the larger Kamoa-Kakula copper project in the Democratic Republic of the Congo.
The company said in its Feb. 26 release that the update results in the project ranking the world's fourth-largest copper discovery, with copper grades beating those of the world's top 10 copper deposits.
Ivanhoe Mines has a 39.6% interest in the joint venture, which includes Zijin Mining Group Co. Ltd. with a 39.6% stake and the DRC government with a 20% stake.
Using a cutoff of 3% copper, Kakula hosts indicated resources of 174 million tonnes grading 5.62% copper for 21.5 billion pounds of copper, with inferred resources of 9 million tonnes at 3.66% copper for 700 million pounds.
The previous resource estimate, released in May 2017, outlined indicated resources containing 15.6 billion pounds of copper and inferred resources containing 1.1 billion pounds of copper at the same cutoff grade.
Using a lower cutoff of 1% copper, Kakula's indicated resources increased 58% to 585 million tonnes at 2.92% copper for 37.7 billion pounds of copper, with inferred resources of 113 million tonnes grading 1.90% copper for 4.7 billion pounds.
"If we lower the copper cutoff 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," Ivanhoe Executive Chairman Robert Friedland said.
Combined with the Kamoa deposit and using the 1% copper cutoff, the project hosts indicated resources totaling 1.34 billion tonnes grading 2.72% copper for 80.7 billion pounds and inferred resources of 315 million tonnes grading 1.87% copper for 13 billion pounds.
The updated estimate is based on data from about 151,000 meters of drilling completed through the end of 2017. Drilling is ongoing with nine rigs and is expected to result in further increases and upgrades to resources
Ivanhoe Mines said the Kakula deposit has been defined over a strike length of 13.3 kilometers and remains open for expansion, while the remainder of the southern parts of the Kamoa-Kakula mining license remains virtually untested.
Geophysical surveys are also underway to help identify new exploration targets within the Kamoa-Kakula mining license.
The company also said it has been assured that a detailed consultation process over the DRC's proposed mining code will start in the near future, with a view to reaching a more collaborative and sustainable framework for development in the resource sector.