Study on the Inlay Characteristics and Occurrences of Yunnan Porphyry Polymetallic Gold Deposits

Abstract

BACKGROUND In the Western Yunnan, there is an abundance of low-grade gold resources with uneven grain size, complicated ore structure and incomplete separation. Using the traditional mineralogical analysis process, it is difficult to achieve accurate and rapid determination of the occurrence of gold and the inlay characteristics of gold-bearing minerals. OBJECTIVES To study the mineralogy process of polymetallic gold ores in Western Yunnan. METHODS:The mineral composition, dissemination size, and inclusions characteristics of gold ores were analyzed, and the effect of mineralogical properties of gold-bearing minerals on the recovery of gold was determined. The X-ray Fluorescence Spectrometer and eight-lamp flame graphite furnace integrated Atomic Absorption Spectrometer were used for the analysis of ore properties, and the ore samples were analyzed by Mineral Liberation Analysis. RESULTS The results show that gold is mainly in the form of free gold, with superfine dissemination size of gold minerals, mainly concentrated on the 0.01 mm to 0.02 mm granularity level. Gold smaller than 0.074 mm presents as free monomer natural gold, which accounts for 50.08% of the total gold. Other gold occurs as inclusions in pyrite, magnetite and chalcopyrite. However, the gold-bearing minerals have small grain size, poor dissociation, and uneven embedding. CONCLUSIONS Increasing the dissociation degree of major gold-bearing minerals is an important method for increasing gold recovery.

Keywords

• porphyry type polymetallic gold deposit
• process mineralogy
• mineral liberation analysis
• dissociation degree of minerals