Hot work in the desert: One of the six ROC F7 rigs at the mine sites in northern Chile.

New ROC F7 crawler fleet makes its mark in Chile

PRODUCING A HIGHER RATE OF NITRATES

At the five mines and seven production plants of the Soquimich company in the Atacama Desert region of northern Chile, there is an ongoing policy of continuous improvement in all operative units.

This includes all drilling operations in the mines - and higher performance and lower costs have been achieved through a smooth transition from pneumatic to the very latest hydraulic drilling equipment and techniques.

Leading producer

Chile is virtually the only country to produce sodium and potassium nitrates, commonly known as saltpetre, and Soquimich is the world-leading producer. It is estimated that the deposits of nitrate ore have reserves which can be mined for another 50 years.

The crude nitrate ore is mined in open excavations, using a quarrying system. The operations include removing overburden, drilling, blasting, loading and hauling the nitrate to the crushing plants.

There, 71% of it is leached in shallow pans to recover nitrates, iodine, sulphates and other salts, which are then treated in different plants to obtain the final products. The remaining 29% is sent to leaching stacks, where salts are also recovered.

Somich, a subsidiary of Soquimich, operates the five mines and Atlas Copco equipment has played a major role in the evolution of current drilling methods at the sites.

When operations began in 1926, 58 wagon drill rigs were needed for production. In 1981, five Atlas Copco ROC 302 drill rigs and 18 drilling units from another supplier were needed to produce 15.5 million tonnes of ore annually. Today, just six Atlas Copco F7 crawler rigs are producing at the rate of 18 million tonnes per year.

The six new new rigs were delivered in August last year and quickly proved their worth, providing even more drilling power, longer drill steel life and better all-round production performances.

In fact, with a rate of production now running at 450 m/shift, it has been possible to further reduce the size of the fleet by keeping one rig on standby - and still meet the demanding targets.

In addition, Soquimich signed a new five-year service and maintenance contract for work at the mines, where Atlas Copco had already been supplying drill steel under a cost-per-metre contract agreed in 1993.

Mine Manager Eduardo Arce: "Atlas Copco's support is very important to us."

Excellent supply

Says Mine Manager Eduardo Arce: "We are more than satisfied with the ROC F7 rigs. Compared with the crawler rigs from another supplier which we previously used, performance is 20 per cent better and the number of effective operational hours has increased by five per cent.

"The service and spare parts supply contract is excellent and enables us to maintain a constant level of drilling costs over a long period.

"And, for the first time, we are virtually dependent on a single supplier as we also have the drill steel supply contract with Atlas Copco Rock Tools.

"With the exception of the rig operators, everything to do with drilling is now in the hands of Atlas Copco and the support we get from the company is very important to us." Mr Arce concludes: "The operators at the mines are also extremely happy with the new rigs.

"They like the very comfortable cabin design, the excellent visibility - and the fact that they can now start collaring holes immediately, without wasting time finding the hole position as they did previously."