Sunstone Metals (ASX:STM) said it is well advanced in its due diligence investigations in relation to a partnership opportunity where a confidential and incomplete non-binding indicative offer could be finalized in the short term, according to a Wednesday Australian bourse filing.

This stage would be followed by a confirmatory diligence phase and the firm is engaging with the party, per the filing.

It is separately progressing due diligence and commercial discussions for a material transaction, which may result in a nearer-term, privately owned gold development asset being combined with Sunstone's two large gold-copper assets.

There is no certainty or assurance that any of the proposals will be received, or will result in a binding transaction, it warned.