Enrichment Mode And Metallogenic Potential Of Au In Coal And Ash In The Target Area, Southwestern Guizhou Province

Based on regional and vertical distribution character of Au in Southwestern ofGuizhou, occurrence characteristics of Au in coal and migration mechanisms of Au incoal ash were analyzed in detail by the method of coal petrography and quality,mineral petrology and geochemical. According to geological and geochemistrybackground of Au in Southwestern of Guizhou, main factors of Au enrichment inthree geochemical zone were studied respectively then the mode of Au enrichment incoal and ash in Southwestern of Guizhou was established. The forecast region wasdelineated and the geological resource of Au in coal was reckoned by analyzingmetallogenic potential of Au in coal and ash in Southwestern of Guizhou. The mainconclusions and achievements are listed below:(1)The content of Au in coal in Southwestern of Guizhou is generally high. Theyare higher than the rest of mines in Shuicheng Mine, Xingren Mine, and Anlong Mine.Au content in the upper Longtan Formation is lowest among the overlying ChangxingFormation and the underlying lower Longtan Formation, and Au content inChangxing Formation is highest. Because of the effect of Au occurrencecharacteristics in coal, Au is volatile in the progress of coal combustion in general,therefore most of Au is volatilized into air and Au assigned in ash is lower. Au mainlyexist pyrite (hydrothermal alteration), quartz, clay minerals and organic matter withnano-Au, lattice Au, Au+, Au3+etc. in coal.(2)Emeishan basalt, Goldfield (provide Au source), Low-TemperatureHydrothermal Fluid, Deep faults, Solution caves, Fractured zone (activate and migrateAu), Lithologic combination, Minerals in coal, Coal quality (precipitate and enrich Au)such geological-geochemistry conditions effect Au enrichment in coal. Establish Auenrichment mode in coal and ash in Southwestern of Guizhou.(3) Fixative nano-MgO (addition quantity is0.2%coal-fired), Fe2O3(additionquantity is3.58%coal-fired) and low-temperature ashing have significant influenceson enrichment of Au in coal ash. They can make the utilization of Au in coal ashmore practicable. The matallogenetic prognosis areas are delineated and thetheoretical geological reserve of Au in coal and ash is reckoned. Results showed thatAu in coal and ash have metallogenic potential.