Africa-focused Ivanhoe Mines reported last week that it had inter- sected “unprecedented” min-eralisation in an exploration drill hole at its flagship South African Platreef precious metals project.

The company said it had found 4.51 g/t of platinum, palladium, rhodium and gold (4E) over 90.64 m, at a 1 g/t platinum, palladium, rhodium cutoff in Hole TMT006 at the underground Flatreef 4E/nickel/copper discovery, which is part of the company’s Platreef project in South Africa’s platinum-rich Bushveld Igneous Complex.

The intersection also had more nickel and copper, grad-ing 0.37% nickel and 0.20% copper, and a platinum-to-palladium ratio of about 1:1, over the entire 90 m intersection. Company founder and executive chair-person Robert Friedland previously described the deposit’s copper and nickel content as being potentially enough to allow it to produce 4Es at negative cost.

“This is an extraordinary drill hole. The 90 m thickness of the intercept, which roughly is the same height as a 30- storey building, is unprece-dented at Flatreef and I believe it also is without precedent in an underground platinum discovery in South Africa.

“The scale of the mineralised intercept has obvious implica-tions for the contained plat-inum-group metals (PGMs) and base metals in the open-ended Flatreef polymetallic discovery. “The combined grade and thickness of the PGMs and base metals mineralisation seen in this hole far exceeds anything we’ve previously encountered in all our years of delineating resources on our Platreef project,” Friedland said.

The company said the gentle dips in the Flatreef discovery area meant that the drilled thickness was close to the deposit’s true thickness.

The high-grade mineralisa-tion starts at a depth of 803.43 m below the surface and continues to a depth of 894.07 m. The two mineralised reefs that comprise the upper-most mineralised portion of the Flatreef discovery – T1M and T2 – are next to each other in this area, which was a contributing factor to the size of the intersection.

Hole TMT006 is collared about 360 m south of the loca- tion of the $80-million bulk- sample shaft, which recently received approval to proceed from the South African govern-ment’s Mineral Resources Department.

Previous drilling by Ivanhoe Mines at the Flatreef discovery produced combined intercepts of the T1M and T2 zones that averaged 24 m in thickness. This was exceptional for the Bushveld, where many under-ground platinum mines have averaged thicknesses of 0.4 m to 1.5 m.

Since drilling resumed at the Platreef project in June, a total of 24 759 m had been drilled in 22 holes and 11 deflections, representing about 70% of the planned 2013 development drilling programme. Ivanhoe expects to com- plete the 2013 drilling pro-gramme in mid-December, which will bring the total drilling to 709 400 m at the Platreef project since the pros-pecting rights for the Turfspruit and Macalacaskop licences were acquired in February 1998.

Ivanhoe intends to undertake a three-dimensional (3D) geophysical seismic survey over the Flatreef discovery before beginning site preparation work for the bulk-sample shaft. The seismic survey was expected to begin last week and will be complete early next month.

Terrace and collar designs for the 7.25-m-diameter bulk-sample Shaft 1 have started and contractor mobilisation and site preparation are expected to start in December, once the preliminary results from the 3D survey have been received.

About 250 contract employees will be working on the 800-m-deep shaft once the sinking work begins, raising the number of people employed at the Platreef project to 550. The vertical shaft will facil-itate Ivanhoe collecting a mineralised bulk sample in the second half of 2015 to complete the company’s development assessment of the Flatreef.

Shaft 1 construction will be funded from the $180-mil-lion in dedicated funds remain- ing in Ivanhoe’s treasury from the $280-million received in 2011 from the Japanese consor-tium of Itochu Corporation, Japan Oil, Gas & Metals National Corporation and JGC Corporation for an 8% interest in the Platreef project.