Research on Mode of Structural Control about Groundwater Pour-in Mechanism in Xiadian Gold Deposits of Shandong Province
As the typical vein struntural fissured water pour-in deposits, Xiadian Gold deposits of Zhaoyuan city in Shandong province have the history of exploitation of more than twenty year. The depth of mining increased from -155m in the initial period to -654m of nowadays (ground elevation at +157m), the problem of groundwater pour-in makes great difficult to exploit in depth, the research in groundwater pour-in mechanism has always been a great difficulty in mineral deposit hydrogeology study. With the increasing of mining depth and the extending of yield scale, hydrogeological conditions in deposits have changed a lot, groundwater pour-in brings in many bad influences, such as threatening manufacture safty, decending exploitation efficiency, increasing cost, etc. In the process of draining, source, passageway and affect factors of groundwater pour-in are not clear, and the draining effect is not satisfied, as lack of detailed research on the complication of hydrogeology conditions in the beginning of construction.As far as the formation of deposit hydrogeological types, it is different between groundwater pour-in mechanism of structural formation and the mechanism of other types, the study on deposit hydrogeology is particular, and in the aspects of theory and practice, it makes great sense of researches on the pour-in mechanism of Xiadian gold deposit.According to the discussion of area structural background and minal hydrogeological conditions, as well as the changes of pour-in conditions and deposit outlet characters, this paper analyzed the mode of structural contral about deposit pour-in mechanism basing on the theory of Zhaoping structural dynamic system. Through the analysis of water pour-in fissure structural mechanism, distinguished the controlling factors of Xiadian gold mine water pour-in, also demonstrated the structural mode of deposit pour-in mechanism. Finally, at the control mode of faulted structure, the formation and variety rules of deposit pour-in was discussed.The structural controlling factors of Xidian gold mine water pour-in is determined by Zhaoping faulted structure, and it is consistent with structural dynamic system. Its formation come through four phases of pre-Fenzishan transfigurate age, Fenzishan movement age, Hercynian-yanshanianblock-faulted structural age and Mesozoic Era dynamic-heat field working age, moreover, it has the charactors of multi-orientation, multi-period, shearing character and additiveity. Structural fissures interlude and connect with each other, and formate the fissured water-bearing rock attached to the ores. By inverstigating, the action of faulted structure controlling pour-in mechanism presents on water transimitting of several different oriented structure fissure, such as NE-NNE oriented press-wrest rupture, NW oriented wrest rupture and EW oriented tension rupture.Structural dynamic system of Zhaoping rupture makes the primary controlling affect on the groundwater pour-in, and the affects become weaken with the increasing of mining depth, such as precipitation and surface water etc. The controlling affect of rupture structural fissured water on the pour-in water is prominence.According to the investingation and researchs source, passageway and affect factors of groundwater pour-in, this paper explain that the vein structural fissured water is the direct source of groundwater pour-in in Xiadian gold deposits. As the depositing layer determine the mining layer of gold deposits, the vein structural fissured water became uncoverd with the increasing of depositing depth, and turned into the direct source of groundwater pour-in, it is confirmed the mode of structural control about groundwater pour-in mechanism in Xiadian gold deposits. Characteristics of groundwater pour-in are consistent with the source, passageway of water pour-in, affluenced by the rupture zone structural control. The positions are ununiform, flowing yield change feebly, it is incarnated the mode of structural control under the structural dynamic system of Zhaoping rupture. The changing characteristics of flowing yield are the embodiment of Zhaoping structural fissured system in the groundwater pour-in condition.Compared with surface water and superficial groundwater, the hydrochemical characteristic of water pour-in has typical”close”character, it shows that the hydraulic connectivity is badly related in plane orient, but is obvious related in vertical orient. There are some rules about the concentration change of hydrochemical factors with the increasing of depth. So the the hydrochemical characteristic of water pour-in reflect the pour-in mechanism under the mode of structural controlling.Above all, the situation of pour-in fissure zone distributing and development formatted from structural rupture control the groundwater pour-in condition. Mode of structural control about groundwater pour-in mechanism in Xiadian gold deposits is mainly incarnate in the source, passageway and character of waterflow yield. By the study on the mode of structural control about groundwater pour-in mechanism, it is ture that this mode of structural control could manifest the cause of formation about the groundwater pour-in mechanism in this gold deposits and hydrogeological characteristic actually, and explain the changing character of waterflow yield. This paper provided the scientific accordings for the mining of Xiadian gold deposits and the study on mining hydrogeology under similar conditions.