SANTIAGO, July 6 (Reuters) - A Chilean enquiry into whether attempts to move a herd of chinchillas to make way for a gold mine harmed the endangered animals should be completed in the coming months, the environmental regulator's head told Reuters.

South Africa's Gold Fields Ltd, which is building the $860 million Salares Norte mine high in the Andes mountains, has been working with Chilean authorities since 2020 to relocate the chinchillas.

The Superintendency of the Environment (SMA) in November 2020 ordered a halt to efforts to relocate 25 chinchillas after one of the four moved so far suffered a broken leg and two others died.

Cristobal de la Maza, the head of the environmental regulator, told Reuters on Tuesday it was weighing a finding of serious failure, which could result a fine or the suspension of the mine's environmental permits, which could halt the project.

"Right now the investigation is wrapping up and we hope to be able to establish in the coming months whether the company complied with the measures laid out in its environmental permit," he said.

A Gold Fields spokesperson said the company would wait for the outcome from the SMA and for any guidance on how to improve on the relocation strategy, which the spokesperson said was developed by independent environmental experts and approved by the regulator.

"Since the two surviving chinchilla appear to be healthy and thriving, there are lessons from their relocation that could be applied, but we do not want to pre-empt the recommendations of the SMA," Gold Fields said by email.

The company said construction activities at the project were on track in areas where environmental experts say no chinchillas are living.

Hunted for centuries for their thick, soft pelt, the short-tailed chinchilla is classed as critically endangered and is found only high in the Andes Mountains.

Salares Norte is located 1,000 kilometers north of the capital Santiago at an altitude of between 3,900 and 4,700 metres (15,420 feet) above sea level, close to the Argentine border.

The mining project's original environmental impact assessment committed to the removal of 25 chinchillas from rocky outcrops at the intended site of the mine. The project to move them, which cost $400,000, began last August.

Gold Fields had planned to complete construction by the end of 2022, to start production in 2023. (Reporting by Fabian Cambero in Santiago and additional reporting by Tanisha Heiberg in Johannesburg Writing by Aislinn Laing; Editing by Matthew Lewis and Barbara Lewis)