BHP Billiton and Antofagasta Minerals on Tuesday called for greater government dialogue to prevent a controversial copper mining royalty project from affecting competitiveness.
"We respect the dialogue with the authorities," Rag Udd, BHP's head of operations in the Americas, said on a panel at the World Copper Conference in Santiago.
"But the proposed royalty levels would put Chile in an uncompetitive position compared to other jurisdictions where BHP does business."
Chile is the world's largest copper producer and the mining industry claims the tax burden from the new royalties will increase further at a time when companies are already struggling to offset falling ore grades across the country.
A Senate committee is expected to vote on the royalty on Tuesday and, if approved, it would go to the full Senate.
Antofagasta's chief executive, Ivan Arriagada, said the latest changes raise the total tax burden to as much as 48%, compared with 41% in rivals such as Australia and Peru.
"I hope there will be an opportunity in the next (legislative) phase to continue to work together," Arriagada said.
The royalty program is part of a larger change in revenue pushed by the administration to fund campaign promises. The administration had already suffered a major setback when Congress shelved its tax reform proposal in early March.
