This item is a special case of the classic refractory problem, but with a very important difference, the problem is detected by microscopic devices. Previously was mentioned the effect of particle size on gold recovery. When there are tools to detect the problem at the beginning of the test work program, the metallurgist will be able to prepare a testing program considering this problem. The problem is basically gold liberation. As gravity concentration is not a good option, the next two alternatives are flotation and or cyanidation. The first one could concentrate part of the gold, but some losses will be related to two factors, gold particles liberation was not achieved and excessive presence of fine particles are a poison for the process due to they take part of the flotation reagents and modify the rheological properties of the slurry.
The success of cyanidation is related to the gold particles liberation obtained during the primary grind. If the problem is not very serious, the process could solve the problem, but if there are encapsulated gold particles, the process could not give an acceptable recovery.