Analysis Of Field Information Of Geogas And Its Application In Concealed Metallic Ore Exploration

Geogas survey is a new prospecting technique which was born in the 80 century, it has Characteristics of accurately projection plane positioning, high detection sensitivity in the detection of concealed metal deposits, it is one of the important means in the detection of hidden ore deposits. This paper discusses the gas migration disciplinarian and gas source area based on gas migration model experiment, it also analyzes the gas filed source of metal deposit for example North Guangxi Dachang concealed zinc copper mine, then uses gas detection means to do exploration and prediction in Dongshan lead-zinc deposit and Hongnipo-Banshantou that located outside the Lala copper deposit.Gas migration experiment shows whether it is a single layer model or the ore body and surrounding rock model, both main ore-forming elements and other trace elements show different degree emigration under updraft effection that driven by heat, this shows that main ore-forming elements geogas anomaly in the rising air flow that caused by deep concealed ore is objective existence. Because every element has different activity compared with geogas current, different element has different migration rate and emigration ratio. Wall rock has obvious effect on gas field, on one hand, wall rock has trapping effection on rising air, so the content of main ore-forming elements in updraft reduces, but the content of element in wall rock will increase along with the accumulation of time,then this leads the element increasing in updraft and increases the abnormal; on the other hand, the content of main ore-forming elements in wall rock has effect on geogas current that flows through wall rock, this suggests metal elements in wall rock was extracted by geogas current that flows through, then enhances abnormal that abtained from near surface or from surface. But in general, geogas anomaly that can form high abnormal comes from concealed orebody.This paper uses clustering analysis and factor analysis of elements in geostatistics to study gas field source tracing of Guangxi Dachang concealed zinc and copper deposit, the result shows, because the determined anomaly comes from system data derived from geological body composition that after normalization, strong anomalies that under this background of the system are ore induced anomalies and they have the character of a relatively large anomaly intensity and anomaly range is relatively small.This paper also dose prospecting and prospecting prediction on Dongshan leadzinc deposit and Hongnipo-Banshantou area that outside the Lala copper deposit using gas detection means, this shows geogas survey is effective on halfhiddenconcealed metal deposit exploration, the main metallogenic element anomaly forms above the orebody, it has high sensitivity and it can detect orebody that buried deeper than 500m(Dongshan deposit). At the same time, it does prospecting prediction on Fault 18 and Fault 3 in Dongshan ore district and Pointes out the prospecting direction; prospecting prediction on Hongniban-Banshantou area shows there is obvious Geogas anomalies and Cu, Zn, Pb anomalies in soil at sodic volcano rock area, delineates the key anomaly which is prospecting target area.