The Magnetite Deposit Characteristic And Prospecting Assess In Zharigen Area, Golmud City, Qinghai Province

Zharigen Iron Producing Area locates at Tuotuo River segment of the Three-RiverMetallogenic Belt. It locates on the side of Qiangtang Landmass between Bayangala LateIndo-China Period Folding Orogenic Belt and Qiangtang Landmass. The mining areapresents as an anticline with approximately east-west axial direction and incomplete form,and the ground layer is formed by the set of gray-ash black argillaceous and carbonlimestone, feldspar lithic sandstone plus complex conglomerate, intermediate-basicvolcanic lava (andesitic basalt) of Nuoribagaribao Fm of the lower permian seriesKaixinlin. Influenced by the faulting and the invasion activity of sub-volcanic rock mass,each lithology layer exposure is extremely unstable, the occurrence is relatively inordinate,and the layer relationship of each lithology layer is not clear. Through several years ofwork in the study area,78magnetite ore bodies have been found, among which68are orebodies reaching production-grade, and it is estimated that the resource quantity of332+333+334ores is7.1496million tons, reaching medium-and large-scale mineraldeposit standard. The ore bodies are all occurred in intermediate-basic sub-volcanic lava,whose mineral types are relatively simple, and mainly are magnetic pyrite and magnetiteores, and a small amount of hematite and limonite ores. The ore grade is relatively highand even, and the ore body in western ore block is relatively thick: the maximumthickness for single engineer is23.73m, and the average thickness is8.98m; the thicknessof ore bodies at the central and eastern ore blocks is generally1-3meters. The ore-hostingrocks are intermediate-basic sub-volcanic lava formed in Indo-China Period, and theore-bearing rock-body at eastern ore block locates at the anticlinal core and south wing,and the ore-bearing rock-body at central and western ore blocks locates at the north wingof the anticline. The rock bodies are mainly controlled by the sub-volcanic lava and itsinternal structural factures at the early stage, and the ore deposit cause is the postsub-volcanic magmatic hydrothermal type. The tectonic position of the ore-bearingrock-body is in favor of forming relatively large-scale magnetic ore deposit. It isrecommended to apply the magnetic method to seek for magnetic ore in the study area,while the current magnetic anomaly in the mining area has not gone through deepengineering verification or sufficient verification. The drilling engineering controlleddepth is insufficient. Further enhancement of the verification on the existing anomaly willexpand the resource vision; the magnetic anomaly at the south part of the mining area hasnot been entrapped yet, the high-precision magnetic survey range is to be enlarged to discover new anomaly and conduct inversion on the anomaly to determine the distributionrange and spatial form of the magnetic substance, so as to target the advantageous locationof the ore. Thus, it is expected to find relatively large-scale magnetic ore body in the deep.