A ceremony was held to mark the occasion on September 12, during the Eastern Economic Forum.
The London-headquartered miner said that its new heap leach flagship operation in Yakutia is expected to produce 200,000oz of gold annually for a life-of-mine of 17 years - an achievement which will give it the first-ever distinction of being a one-million-ounce-per-year producer.
CEO Nikolai Zelenski said the opening of Gross, which was on time and budget, has brought 900 new jobs to the region and the company is expecting it will be a major economic contributor.
"I believe we have firmly cemented Nordgold as a truly world leading developer of new gold mine assets," he said.
"This gives us even greater confidence as we look to develop our Montagne d'Or asset in French Guiana, which is expected to be a major catalyst for much-needed economic growth in the country."
Gross' mineral resources from the Tabornoe deposit, according to its 2012 JORC report, are estimated to be 9.74 million ounces; ore reserves are estimated at 4.4 million ounces. Construction first began at the site in June 2016.