The former manager of a Northern Territory Manganese mine has given evidence about explosive blasting that may have damaged an Aboriginal sacred site.

The miner, OM Manganese, is accused of damaging a sacred site called Two Women Sitting Down, at the Bootu Creek mine, north of Tennant Creek, in July 2011.

It pleaded guilty in the Darwin Magistrates Court to that charge but not guilty to other offences, including allegations of damage a few months later.

Former manager Paul Carrick told the court some blasting had taken place about 25 metres from the sacred site.

He admitted that if they had doubled that distance, parts of the site would not have collapsed.

He said they had blasted so close to the site because if they didn't, a large amount of manganese ore would not have been accessible.

The hearing is continuing.