In a recent project to reduce costs, the mine replaced two large DTH rigs of rotary design and found that it could cut costs but still sustain productivity.

For Cassio Schittini, Production Manager at Cimento Rio Branco, that was more than enough to meet the company's demands.

He says: "We made a comparison between the performances of the new ROC L8 drill rig from Atlas Copco and the two rigs from a different supplier. The comparison shows that the Atlas Copco equipment has a huge advantage.

"At first we could not believe that such a light machine as the ROC L8 could produce such a high performance. But its capability proved to be very high indeed and it provides all our production."

Innovative partnership

The Saivá mine - which belongs to the Votorantim Group, the largest cement producer in the country - has a current production of 7 million tonnes per year.

Atlas Copco is providing labour, spare parts and drilling consumables, which include the rock drill, according to a cost-per-metre contract.

Quarry Supervisor João Wilson says: "We like the continuous after-sales service and plan to extend it to other quarries in the group. Atlas Copco's positive attitude in helping us to solve our problems has created a genuine innovative partnership."

Now the Votorantim Group has purchased a second ROC L8 unit to use in another mine in the state of São Paulo.

The Saivá mine formerly drilled 6 1/2-inch (165 mm) diameter holes with low pressure, but now, with the new, high pressure ROC L8, it drills 5 1/2 -inch (140 mm) holes. The drilling pattern is 36 m², compared to 46.5 m² for the old rigs.

Advantage high pressure

The ROC L8 rig is operatational for two 8-hour shifts per day, 300 days per year. It uses a COP 54 QHD down-the-hole hammer from Secoroc with an average life of 12,000 drill metres. The 5.5-inch ballistic bits, which last for some 5,000 metres, are also supplied by Secoroc.

The drilling pattern in operation at the site is 4.8 m x 8.0 m. The benches are 15 m high and the drill holes are 15.5 m deep. Hole inclination is 15 degrees and some 7,000 m are drilled each month.

Data shows that changing from 6 1/2-inch to 5 1/2-inch percussive DTH drilling resulted in a saving of some 30% and reduced the consumption of explosives by 6%. This, in turn, resulted in an annual cost reduction of USD 91,000.

Concludes Cassio Schittini: "Atlas Copco is always concerned about every problem we face and thanks to the service contract we can now plan our production accurately.

"This means that the high availability and constant level of drill metres per month keep our costs stable and predictable."