Eastside Project Yields 95% Gold Recoveries

VANCOUVER - Columbus Gold Corporation reported the results of initial metallurgical tests on gold and silver mineralization at its Eastside gold project in Esmeralda County, Nevada.

Fourteen samples of rotary drill cuttings were selected for the initial metallurgical tests using 92 hour, cyanide-leach, bottle roll tests. Test work was performed by Kappes, Cassiday, and Associates (KCA) in Reno, Nevada. The samples were selected to represent a wide range of gold and silver grade, differing depths below the surface, differing areas of the deposit, and differing oxidation.

One split of each of the fourteen samples was ground to 80%passing 200 mesh. The average recovery from cyanide leaching of this ground material was 95% for gold and 52% for silver. The gold recoveries ranged from 85% to 99%and the silver recoveries ranged from 27% to 79%.

Almost all gold mineralization drilled at Eastside is oxidized with the exception of only one deep intercept in Hole ES-32 which was unoxidized and sulfide-bearing, but is amenable to leaching with cyanide as shown by the KCA leach results of the sample taken from the 965-970 ft. deep intercept in vertical hole ES-32. The gold recovery from this unoxidized sample was 95% and the silver recovery was 79%.

In addition a second split of each of the 14 drill samples was processed as is, or exactly as collected at the drill, with no grinding or crushing. These samples varied greatly from sample to sample in the amount of coarse and fine material present. The largest fragments of solid rock ranged up to .75 of an inch in size. On the other hand, some of the samples had little rock above .5 inch in size. A visual estimate of the amount of coarse versus fine material in each sample, and the maximum fragment sizes present, is contained in the KCA report linked above.

The recoveries from the 14 as is samples by cyanide leaching for 92 hours averaged 57% for gold and 18% for silver. The range of recoveries from the as is samples was extreme, ranging from 20% to 85 % for gold, and from 6% to 52% for silver. The wide range in results does not seem to be due to grade, depth, oxidation, or alteration type, but rather to the variation in the amount of coarse material in the samples. Further testing is in progress, beginning with screen analysis of raw samples.

The purpose of metallurgical tests on as is materials is to begin to understand if Eastside gold mineralization might be processed by heap leach techniques, although it is impossible to predict actual recoveries from such preliminary testing. Much larger samples, usually obtained by core drilling, and metallurgical testing of that core, including column leach tests, will be necessary before one can more accurately predict heap leach recoveries and properly evaluate crushing. Columbus management believes that these results are sufficiently encouraging to proceed with further testing. Core drilling is planned as part of the next drilling program currently being permitted.