Thanks to its rich gold deposits, the Cajamarca region in northern Perú has been home to gold mines since the Inca times. One of the current mines is Cerro Corona, where Robit recently became the preferred supplier of DTH drill bits.

Cerro Corona mine, owned by Gold Fields Inc, is located on the eastern slope of the western Andes, some 80 km north of the regional capital of Cajamarca. The open pit mine is expected to produce some 2.1 Moz (about 60,000 kg) of gold and 407 kt of copper in concentrate over its 15-year mine life.

The rich gold deposit is hosted by diorite porphyry, an extremely hard rock embedded in limestone. MUR-WY, the drilling contractor at Cerro Corona, uses the so-called pre-splitting method, where closely spaced holes are drilled and lightly charged, causing fractures that isolate the gold-bearing rock from the surrounding rock mass. Successful pre-splitting requires very straight holes, and, as always, this should be achieved with optimal cost, penetration rate, and tool lifetime performance.

Robit believed their tools might improve productivity, so they contacted MUR-WY in 2021 to arrange test drillings for 5” DTH bits at Cerro Corona. Test drilling is typically a very hands-on type of work where you monitor and make adjustments on the spot with the contractor. However, the COVID pandemic complicated things.

“In 2021, access to the mine was heavily restricted, so we had to get creative with MUR-WY to follow up on the tests. We ended up monitoring the performance remotely through WhatsApp videos and messages”, says José Luis Cisneros, General Manager of Robit SAC.

Luckily the restrictions were eventually lifted, and Robit’s Regional Sales Manager, Martín Rodriguez, was able to revisit Cerro Corona and conclude the tests, which proved highly successful.

“On average, compared to the tools they had used, we reached 20 to 25% better yields with our DHD340 Flat Face Premium bits and 40 to 50% better with our D45 HD hammers.

“We detected several ways to improve productivity. Not only did Robit’s components perform better, but a key factor is also the service we can provide. We are now the preferred supplier for DTH consumables at Cerro Corona. There are still challenges to tackle, but we will work with our strategic partners from MRU-WY to articulate better ways to approach their needs and increase security regarding the project’s required logistics”, Martín says.

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