There are now 572,100 ounces of the yellow metal in the higher measured and indicated category, and 544,300 ounces of gold in inferred.
That compares with the estimate in July last year, of 375,869 ounces in indicated and 166,141 ounces of inferred.
The overall measured and indicated resource now stands at 15.5 million tons at a gold grade of 0.037 g/t, while the inferred resource is18.5 million tons at 0.029 g/t of the yellow metal.
The Atlanta resource also contains 5.8 million ounces of silver in measured and indicated and 3.9mln ounces silver in the lower inferred category.
Consultants estimated the resource based on 34,919 feet of drilling in 21 core holes and 22 RC holes conducted by Meadow Bay in 2011 and 2012 as well as historical drill data.
Chief executive Robert Dinning told investors: "In the two years since Meadow Bay acquired the Atlanta project we have more than doubled the resource.
"And we did this at a discovery cost of under $10 per ounce. Based on the model put together by Gustavson Associates, we are confident that we can build upon this resource through additional cost-effective exploration."