TA/chart, page-311

I read that too. It's not new. It was discovered 5 years ago and it might be many years before it's mined. It's good that there is a large phosphate deposit there to help with future global supply when needed but the majority is deep so what will it cost to mine?
MNB's fertiliser will be locally produced (much less freight cost to local markets) from a high grade open pit resource (low mining cost).
On top of that, MNB's phosphate is ideally suited to Angola's soil so that a beneficiated product, produced and sold at relatively low cost makes imported products less attractive. Most phosphate (unlike MNB's) needs to be processed further to make a useable product.

From your link;

"The ore body in the ground, which was originally estimated to extend 300 meters below the surface was in fact running 4,500 meters deep, the company found out.

“When we discovered that, we did two drilling programmes in two zones. And on those two zones, down to 400 meters, we established two world-class resources, which allows each of the zones to supply raw materials for at least 50 years,” Wurmser said.

It is currently impossible to drill at depths of 4,500 meters so the geologists working on the project evaluated only a third of the volume, down to 1,500 meters from the surface."