| The Bayanhar Obo gold deposit in inner Mongolia,located in the secondary structural belt of Xilinhaote-Erdaojing,is a medium scale tectonic alteration rock type gold deposit.The study on ore-smelting performance and reserves estimation of the deposit can provide an important basis for mine construction and production.Guided by the theory of mineral exploration,through topographic survey,geological mapping and different geological working methods,the exploration type of the deposit is determined to be type I-II.By surface trench exploration and deep drilling,the geological characteristics,ore body distribution and characteristics,mineral composition and structure of ore are systematically identified,which lays a foundation for the experimental study of ore washability and the study of resource reserve estimation methods.The outcropping strata in the area are very simple,mainly sericite-quartz-schist,chlorite-quartz-schist and ferruginous quartzite of Wenduermiao Group.The structure of the mining area is NE~EW trending as a whole.The ductile shear zone in Sonid Left Banner provides favorable conditions for mineralization and hydrothermal transport.The secondary NE,NW and near SN fault are the main ore-hosting structures.Magmatic activities are frequent and magmatic rocks are widely distributed in the area,mainly including ultrabasic rocks,quartz-diorite in the early Variscan,biotite granite in the middle Variscan,granodiorite in the late Variscan and small-scale granite,diorite and quartz-porphyry in the Yanshanian,and a small number of granite dikes and quartz dikes.The ore bodies are mainly layered,stratoid or lenticular in the contact area between Wenduermiao Group and Variscan granite and quartz-diorite,and the main wall rocks are chlorite-quartz-schist and sericite-quartz-schist.The ore structure is mainly scaly metamorphic structure,semi-automorphic to heteromorphic grain structure,and disseminated tectonic.Metallic minerals include natural gold,hematite,siderite,tungsten-manganese-iron ore,pyrite and so on.Natural gold is mainly distributed in pyrite crystals;gangue minerals mainly include quartz,mica minerals,garnet and chlorite.Based on the theory of mine construction,combined with the structural characteristics of ore,according to the study of ore characteristics,cyanide leaching test,column leaching test and heap leaching test,it can be concluded that the ore in this area belongs to low-grade gold ore(Au 0.830g/t),with medium hardness,medium wear resistance and deep oxidation.Applicable to cyanide gold extraction,cyanide leaching(leaching rate 97.71%)and column leaching(leaching rate 83.73%)can achieve a high leaching rate.However,due to the low gold grade of the ore and the comprehensive consideration of production cost and other factors,heap leaching scheme is recommended to treat this kind of ore according to the test results.By using ordinary Kriging method,3D mineral resource evaluation software version SURPAC5.2 for data processing,the establishment of geological model is established and the reserves of resources are estimated.There are five orebodies involved in the estimation of reserves,numbered as I-1,I-2,II-1,III-1 and III-2,and No.II-1 is the main orebody.By fitting the theoretical curve,the variation function is finally determined and the reserves are estimated.By comparing the results of “Inverse distance weighted method” and “Block model volume method” with the results of the block model results with established in the paper,the error is within the allowable range,which ensures the accuracy of the block model results in this area.The results are as follows: No.I-1,ore quantity: 581923 tons,metal quantity: 394kg;No.I-2,ore quantity: 511871 tons,metal quantity: 450kg;No.II-1,ore quantity: 1421988 tons,metal quantity: 13144kg;No.III-1,ore quantity: 29 394 tons,metal quantity: 24kg;No.III-2,ore quantity 83244 tons,metal quantity: 211 kg. |
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