The company's shares, which spent much of 2018 around C7c, hit their highest point in about two years in January when it announced the Salbora discovery and continued to climb to C18.5c last week.
Goldsource said it had initially drill-tested a gold mineralised footprint at Salbora of about 150m by 100m by 30-60m deep, which was open to depth and along strike and part of a potentially mineralised footprint of up to 1000m by 50-100m and open at depth.
"The grade and potential size of this new area has the possibility of being transformative for Goldsource," president Yannis Tsitos said.
Further step-out diamond drilling is planned.
The latest results included 39m at 2.78g/t gold and 49.5m at 2.9g/t, both from surface.
Salbora is about 1.5km from the company's Eagle Mountain resource, where Goldsource built and operated a gravity pilot plant in 2016.
The company is aiming to become a low-cost gold producer in Guyana.
It has working capital of C$1.3 million (US$0.97 million) according to a presentation last month, after closing an upsized $1.3 million placement at 5c per unit in January.
Its shares closed down 2c to 14.5c yesterday, putting its market capitalisation at $35.9 million.