Gold Road Resources (ASX:GOR) has determined the Gruyere underground exploration target estimate to be in the range of 25 to 31 million tonnes at 1.20 to 1.47 grams per tonne grade of gold for 1 million to 1.5 million gold ounces on a 50% basis, according to a Tuesday filing with the Australian bourse.

The target is based on results from its underground scoping study, the filing said.

The assessment outlined a sub-level cave underground mining option, determined at AU$2,240 per ounce of gold, which can sustain production at Gruyere at scale, per the filing.

The company's mineral resource exclusive of the ore reserve at Gruyere is 45 million tonnes at 1.51 g/t gold for 2.2 million ounces on a 50% basis, the filing stated.

Gruyere is a 50-50 joint venture with Gruyere Mining Company.

Gold Road's shares were up 3% in recent trade.