Metalla will make an upfront payment of $2.2 million cash and 2.6 million shares.
"FMS represents the next leg in the growth at the Moose River Consolidated gold mine that has undergone extensive drilling aimed at expanding the resource," Metalla CEO Brett Heath said.
FMS is being developing as part of Atlantic's multi-phase mine plan outlined in a January 2018 pre-feasibility study. Production of 80,000 ounces of gold is expected to start in 2021 following an investment of C$123 million with the mine-life set at five years.
The gold concentrate will be processed at Atlantic's central milling facility at Touquoy, 57km away.
FMS has proven and probable reserves of 432,000oz from 10.8 million tonnes grading 1.24g/t and measured and indicated mineral resources of 452,000oz from 10.6Mt grading 1.33g/t.
In January, Metalla closed a C$6.8 million private placement to secure funds to use to finance royalty and stream acquisitions.
Metalla has royalties on two producing assets and four assets in development, in addition to exploration assets.
Metalla (TSXV:MTA) shares rose 2.88% Monday to C$1.07 per share, an increase of 21c since the start of the year.