It said the deal covered Con and adjacent areas, and superseded the exploration agreement struck between the pair in September 2020, under which Gold Terra could earn up to 60% of Newmont's holdings south of the former mine.
Gold Terra chairman Gerald Panneton said the new option agreement was a significant step towards increasing the company's inferred resource base of 1.21Moz.
"The additional land package along the Campbell Shear, and all the surface access assets and associated infrastructure, will allow Gold Terra to accelerate its exploration strategy with the aim of adding a target of 2Moz of high-grade resources base to sustain the development of the project in the future," he said.
Gold Terra had reported results last month including 8.35m at 5.07g/t from drilling on the Campbell Shear.
The high-grade Con mine was said to have produced 6.1 million ounces and was closed in 2003 due to low gold prices by Miramar Northern Mining, which was acquired by Newmont in 2008.
Con had remaining historical proven and probable reserves of 562,921 tonnes at 0.33oz/t for 188,161oz, based on a $370/oz gold price, Gold Terra said.
Under the new deal, Gold Terra must spend at least $8 million over four years, including the $3 million spent to date under the earlier agreement.
It must complete a prefeasibility study and establish a minimum 1.5Moz in all categories, obtain approvals to purchase and transfer Miramar's assets and liabilities to Gold Terra, post a cash bond to reflect the status of the Con mine reclamation plan at the time of closing, then make a final cash payment of $8 million.
Newmont would retain a 2% net smelter return royalty, which could be halved for $10 million, and a two-year back-in right for a 51% stake.
Newmont's strategic investment at 21c per share would give it less than 5% of Gold Terra.
Gold Terra said it planned to use the Newmont funds primarily for exploration at Con.
Gold Terra had raised $2.88 million in March at 36c per flow-through share and had $3.2 million in cash and equivalents at July 31.
Its shares (TSXV: YGT) have ranged from 16-38c over the past year and closed up 2.1% yesterday to 23.5c, capitalising it at $44.5 million (US$35 million).