Study of the Gold Occurrence and Gold Minerals' Characteristics in the Laozhaiwan Gold Deposit,Yunnan Province

Laozhaiwan gold deposit is a micro-fine grain gold deposit of the sedimentry with the major gold mineralizated in four altered types which include silicification of the quartz sandstone,silicon arsenopyrite pyrite silicon-quartz sandstone,quartz sandstone and clay weak limonite-arsenopyrite clay diabase.The gold often occurred as independent gold mineral,while a few gold occurred in depersing state.Native gold is the main gold in ores,and natural silver is the the second.Gold minerals occur in the gold arsenopyrite,pyrite,stibnite and organic matter(colloids)and other major gold minerals in form of isomorphic,wrapped gold,gold and intergranular cracks.Gold mineral form are various,with particle size less than 1 μm,belonging to ultra particulate gold.Gold mineral characteristic reflecting the gold deposit forming materials mainly come from igneous rocks in this area,mineralization and Hualixi-Indo alteration of diabase-related.This consistent with the understanding about the mine formation in the past studies.