Abstract: In order to provide theoretical support for a modification of the original process of cyanidation leaching process,the chemical composition,mineral composition,particle size distribution and dissemination characteristics of gold ore in Chaihulanzi were detailed using chemical analysis,microscopy，automatic mineral analyzer,scanning electron microscopy,X-ray energy spectrum analysis and optical microscope analysis.The results indicated that the Au contents of the ore was 2.83 g/t,and the gold mainly exists in the form of electrum.The main gangue minerals were quartz,epidote,chlorite,sericite and calcite.The mineral composition of gold ore was complexed,and the distribution of gangue minerals was very fine,which belonged to quartz vein type gold deposits.The occurrences of electrum in the gold mine was wrapped gold,intergranular gold and fissure gold.Pyrite and pyrrhotite were the main gold bearing minerals with the relative content of 41.61% and 23.77%,respectively.Based on the results of process mineralogy analysis,an environmental protection process of stage grinding with gravity separationflotation combined process was proposed.

Key words: process mineralogy,gold mine,mineral composition,dissemination characteristics,green and environmental protection