Positive Metallurgical Studies On Mag Open Pit

GOLDEN, CO - Atna Resources Ltd. reported results of metallurgical test work completed as part of feasibility study on the Mag Open Pit project on the Pinson property in Humboldt County, Nevada. Column leach testing of weakly oxidized to oxidized samples indicated an average 65 percent gold recovery from all ore types at a minus 2 inch crush size over a 60-day leach cycle. Nearly 90 percent of the ultimate recovery was realized in the first 30 days of the leach cycle. These results confirm heap leach recovery achieved from the previous operation.

"The Mag Open pit is a proven gold producer with over 360,000 ounces of historic gold production from 1984 through 1999. The present measured and indicated gold resource totals 982,000 ounces grading 0.039 ounces per ton. The high gold recovery achieved at a course crush size is positive news that justifies advancing feasibility work on the project", said James Hesketh, President and CEO.

Large diameter core holes (~3.5 inch; PQ-size) were drilled in the Mag pit to capture metallurgical samples. Test work included bottle roll cyanide solubility tests, solution chemistry optimization, and column leach testing as part of the on-going project feasibility work.

Three column leach composites were selected from the drilled sample materials to evaluate three ore types: 1) Weak to moderately oxidized ore-grade material (Column P-1); 2) visually unoxidized ore-grade material with low preg-borrowing characteristics crushed to 80% passing 2 inch size (Column P-2) and? Inch size (Column P-5); and 3) Unoxidized ore-grade material with high preg-borrowing characteristics and low bottle roll cyanide solubility (Column P-3). Additionally, a fourth column (P-4 a composite of P-1, P-2, & P-3) was tested which combined the three ore-types to simulate the real leach pad environment where all ore types are stacked on the leach pad and become part of the overall leach column.

NaCN consumption was moderate with an average of 2.79 pounds per ton and lime additions were elevated at 17.4 pounds per ton of ore. Lime additions were made specifically to elevate the pH of the leach solution to a 11.5-12.0 to optimize gold recoveries based upon bottle roll testing which yielded, on average, an eight percent increase in gold recovered when compared with conventional leach solution standards at a pH of 10 to 10.5. Elevation of the pH, in the case of the Mag Pit mineralization has the effect of decreasing the preg-borrowing characteristics of the materials allowing for a greater overall gold recovery. Another material result of the testing was the comparison between the -2" crushed column (P-2) with a duplicate sample split crushed to the finer, -1/2" sized material. There was nearly no difference in the ultimate recovery and which indicates the project will not require a tertiary crushing circuit to liberate the gold.

The Mag Open Pit project is located adjacent to Atna's Pinson Underground Mine site in Humboldt County, Nevada. The Mag project is a Carlin-type gold system located along the southern portion of the Getchell Gold Belt in north-central Nevada. The Company is currently working on feasibility-level studies on the project.