外文翻译-深矿区喀斯特水的运动特征

英文原文Movement characteristics of Karst water in a deep mining areaCHAO Chen-ming1，BAI Hai-bo2，MIAO Xie-xing2,3，YAO Bang-hua3 1China Coal Research Institute，Beijing 100013，China 2State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of MiningTechnology, Xuzhou，Jiangsu221008，China3School of Sciences，China University of MiningTechnology，Xuzhou，Jiangsu 221008,ChinaAbstract：In order to study the movement characteristics of groundwater in a deep mining area and solve the dispute of the distribution rule of hydrochemical zoning which is contradicted by lixiviation water zoning in a horizontal direction, we directed our attention to the source Of degroundwater, its seepage and hydrochemical characteristics in a typical mining areaWe used a neotectonic water-control theory,chemical and isotope methods, as well as a method for analyzing dynamic groundwater conditions.The results indicate that 1)Karst water in the deep and medium parts of this mining area is recharged by vertical leakage through neotectonic fractures rather than seepage along strata from subcrop parts or surrounding flows；2)From surface to deep leakage paths, the variation in the types of chemical groundwater agrees with the normal lixiviation water distribution rule and the age of mixed groundwater increases；3)The warer-rich zones along neotectonic fractures correspond with water-diluted zones in a horizontal direction；4)The leakage coefficient and water capacity of aquifers increases during the flow process of Karst water along the antidip direction(from west to east)and 5) Karst water in shallow mining areas forms a strong runoff belt along strikes and quickly dilutes the water from deep and mediuln mining areas. Overall, chemical and dynamic water characteristies actually agree with in terms of the entire consideration for differences in vertical leakage and abnormalities in the zone of water chemical distribution, along a horizontal runoff directionKeywords：deep mine area；Karst water；vertical leakage；water chemicals；dilution1 Introduction A number of studies demonstrate that the extent of mineralization of Karst water increases,with its chemical water type changing gradually and regularly from HC03-，Ca2and Mg2to S042-, Ca2，Mg2 and finally to Cl-，Na+，along the direction of flow. However,the opposite phenomenon is found in some mining areasTake the Luan mining area as an example，where precipitation water is the only recharge source for groundwaterBoth the extent of its mineralization and its chemical groundwater type obey the rule，along the dip direction，mentioned above(from east to west)，which seems to indicate that groundwater flows deep into the mining areaOn the other hand，the flow direction of groundwater should be against the dip direction(from west to east)for the simple reason that the water head in the west is higher than in the eastIn the pastmost exploration and geological studies show that Karst water in this deep mining area is recharged by Karst water from the shallow parts along this stratum or from surrounding flows. As a result, misunderstanding arise. Based on our investigations and studies in this areaover many years，we attempt to demonstrate that the recharge source，channels and chemical type distribution characteristies of deep Karst water in this mining area agree with the direction of its movement，i.e. from west to east，by studying several aspectsThese aspects include neotectonic fractures and their ability to control water distribution and movement, the dynamic water environment，stable isotopes and radio ones，paths and conditions of vertical leakage，etc2 Recharge source of deep Karst water and its mode21 Landform characteristics around the basin The Lu-an mining area is located in the Chang-zhi basin which is in the southeast of Shanxi Province and consists of the Wuxiang，Xiangyuan and Changzhi basins，with their central elevation of 900 mThe eastern side of the basin is the western slope of the Taihang MountainThere are many Torso Mountains and loess hills accumulated bv tlle effect of erosion on the eastern side ofthe mining area where the average elevation is between 1000 m and 1200 mThe Taiyue Mountains is situated to the west of the basin. With the elevation 0f its main peak at 2567 m，while the average elevation ofthe surface watershed in this area is between 1600 m and 1800 mIn the south, the Fajiu Mountains separate the Changzhi basin from the Jinclleng basinIn the north，it borders on the Jinzhong basin through a watershed in the Wuxiang basinThe southern，western and northern sonrce regions of the Zhuozhang River are all in this basin，where rainfall is the only source ofwater recharge for the entire water resonrce in the Changzhi basinBoth surface water and groundwater eventually flow into the Zhuozhang River and then flow out of the Taihang Mountains，without any other river passing through this area Geologically，the mining area belongs to the eastern margin 0f the Qinshui coal field and its overall strike is south-north, with a slight westward deflectionOutside the coal deposit subcrop(east side)is a point with exposed dissoluble rocks of the Cambrian-Ordovician system，where new Karst on the surface and underground is developedThis is recharged by both rainfall and local surface water and water deep in the mining area slowly moves and changes 22 Neotectonic movement and distribufion characterisfics of neotectonic fractures The neotectonic movement starts in the Pleistocene. This area is not only affected by the tensile stress field caused by the subduction of the Pacitic plate，but also by the impact stress fieId produced by the collision between the India and Eurasian plates. It survived the genesis of two rift valleys in the Tertiary Period with the uplift of the entire Shanxi-Shaanxi plateau(the second step)，reviving and reproducing new crannies and cracks, resulting in the formation of relative subsidence in this mining area The eastern mountain area of the Changzhi fault rises by 670 m while the western Changzhi basin decreases by 290 m，so that the difference in height between both sides increased by 960 mThe Taihang Mountains rises by 410 m，reinforcing the erosion ability of the riversDuring the first occurrence of the neotectonic movement, the Zhuozhang River cut off the Taihang Mountains，captured the water system of the ancient Changzhi Lake and caused it to disappear graduallyThe height difference between the eastern and western sides of the Taihang Mountains is so great that the effect of incision by rivers in the western side becomes quite intensive，with a relatively low erosion base-level，so that the depth of buried of groundwater increasedConsequently,the groundwater flow deep into the earth and the depth of the Karst increasedIn the mining area, many old structures，especially some faulted structures，revive and move in different periodssuch as the horst of the Wenwang mountains，the horst of the Ergang mountains，as well as the Changzhi and Lucheng faultsAt the same time，there are some new structures such as the Wangzhuang-Changcun fracture zonesThese newly produced fracture zone-consisting of a series of dense small fracture zones，have no uniform and fixed main horizontal fracture direction(one ofthe reasons why they are not found and identified by past geological coal explorations)，leading the drop in height between the two sides of up to 50 mA steep slope in a NWW direction was produced in the landform which caused a height difiefence of up to 30一50 m in the terrain. These newly produced and reactivated neotectonic fracture zones run through shallow and deep parts of the mining area and divide it into different parts(Fig1)Fig1 Hydrogeology concept model plot23 vertical leakage recharge mode The reactivated old fractures and newly produced ones have become the main leakage channels for surface water to recharge Karst water deep in the mining areaUnder the strata of the coal deposits Ordovician Karst water is recharged by the Carboniferous-Permian fissure water，mentioned earlier,which is replenished by pore water of the Quaternary system，i.e ,the final recharge source is rainf-all and surface waterThe groundwater level of the Quaternary systern in this mining area ranges from+900 m to+930mthe level of hydraulic pressure water in the pores at the bottom of the Quaternary system is+960+880 mThe level of water in sandstone fissures of the Permian is between+770+790 m，the level of the water in limestone-fissures ofthe Carboniferous is +750+770 mEven in the Ordovician Karst aquifers，the water level in the Fengfeng Formation at the topexceeds that of its lower Majiagou Formation by l()-40 m, which is the driving force for vertical leakageThe difference between water levels of the Quaternary system and that of bedrock fissures and Karst is so large that a non-pressure area is formed at the top of the bedrock，which means that the amount of recharge of bedrock water from the Quaternary system almost remains constantThis recharge mode is illustrated in Fig2 with arrowsFig2 Vertical leaking recharge model outline3 Runoff characteristics31 Main runoff direction The level of Ordovician Karst water declines from west to east, with the high level(+660 m) in the Tunliu Mine(deep area)，at a medium level(+650 m) in the Changcun Mine and a low level(+643 m)in the Wangzhuang Mine respectivelyThis indicates that the flow direction of Karst water is from west (deep) to east(shallow)along the antidip direction. It is the point where some earlier hydrodynamic explanations are contradicted by past chemical distribution rules of water, i.e. the flow direetion of Karst water should be from west to east judging from the water headOn the basis of the number of chemical water ions and their distribution rules. It seems that Karst water seeps from east(shallow)to west(deep)along the dip after being recharged at the outcrop32 Development features It is owing to the fact that Karst in this area either belongs to the old Caledonian-Hercynian period or to the new tectonic movement period that water cycle conditions are differentFor this reasonold Karst mainly exists in the Fengfeng Formation(at the top of the Ordovician)and new Karst only evolves into horizontal multistrata Karst caves，based on old Karst on the surface or in shallowburied areasThe three cyclothem of the Ordovician system enable new Karst，inthe shallow parts，to develop and behave as strata-controlling Phenomena with strong and weak interlacingThe effect of dissolution of gypsum leads，in turn，to the appearance of a dissolved breccia zone，a crushed rock zone and a fracture zone above the gypsum stratum and a strong regional water-bearing stratum(from the bottom up)formed under the effect of further dissolutionThe interaction between a strong runoff zone in the shallow and weak parts，opposite the dip and penetrating from the shallow to the deep part，limits the size of the area for dissolved CaC03 and MgC03It is in the shallow part where both the new and old Karst interact；Karst of the Caledonian period at medium depth is filled by sediment3.3 Water capation of neoteetonic fractures The reactivated old fractures and newly produced fracture zones are fan-shaped horizontally and link the weak，middle and strong water-rich Ordovician areaswhich become the main leakage channels for groundwater in the shallow parts to recharge deep Karst water as well as the collection places for Karst water on both sidesThese neotectonic fractures receive recharge water through vertical leakage and horizontal seepage from both sides and flow into the centralized runoff channels to discharge simultaneously(Figs1 and 2)4 Chemical characteristics41 Distribution characteristics of constant ions The media in Karst water of this mining area are carbonate and sulfate rocks，which suggests that the chemical compositions in Karst water are mainly Ca2+，Mg2+，HC03- and S042-The water chemicals gradually change from HC03-Ca2+, Mg2+ toS042-Ca2+,Mg2+，which seems to agree with the characteristic of lixiviation watert，i.e., the direction of groundwater flow is from east to west and the extent of its mineralization increases and changes from HCO3-Ca+, Mg+ to SO42-Ca+,Mg+ and eventually becomes a Cl-Na+ , K+ water type，with an increase in flow distance. Essentially，the formation model of lixiviation water in this area is different from that of normal lixiviation wateralthough it is formed under lixiviationThe great difference for Karst in a vertical leakage coefficient and in water-rock interaction over time，leads to huge differences in the extent of mineralization before the water reaches the aquifcr through vertical leakageTo the west of the mining area，the buried depth of the Ordovician is so great，that the extent of mineralization of Karst water is high as a result of the high mineralization level of recharge water through vertical leakageThe level for recharge water through vertical leakage is low due to the shallow，buried depth in the east and so Karst water is dilutedAt the same time，the ability of water to renew itself in neotectonic fractures is better than that of both sides and so it can obtain more recharge water in shallow parts through leakage，forming a water dilution zone(Fig.1).4.2 Saturation index and characteristics of dissolved material From the calculation of the saturation indices of the main minerals in Karst water,like calcites，dolomites and gypsum，we found that the carbonate minerals are in a dissolved state to the east of the mining area with the amount of Karst still becoming larger,while they are in a state of saturation in both the middle and the west of the mining area with the saturation level and the degree of fill by sediment becoming higher towards the westSulfate minerals in most places are in a dissolved state and tend to be more saturated from east to westA11 old Karst in the west is being filled and becomes compactable43 Distribution eharacteristies of stable isotopes The Changcun mine lies，in a horizontal direction，in the deep part between the An-Chang graben and the Wenwang horstIts western place, 18O is from -0994to-1163and D is from-717 to -808which is the minimum value in this area. 18O, in the area from the Wenwang horst and the Huangnian town to Lucheng town ranges from -0894 to -0947and the D is between-6-3 to -73, which are the maximum values in this areaIn contrast, the 18O and D in deep Karst water are lower over the large recharge distance and are mainly recharged from remote mountain areasCorresponding values in the east(shallow)are higher over small recharge distancesThis proves that the main recharge source and areas for deep and shallow parts of this mining area are different. In the vertical directionthe 18O and D in water of the Quaternary system are larger than in fissure water of the Carboniferous-Permian system which in turn are larger than the values in Karst water of the upper parts of the Ordovician(02f) and the least in Karst water of the lower part of the 0rdovician(02f+s)The proportions of 18O and D in water of the Quaternary syrstem are_一082076 and -658一567 respectively,while corresponding values in the water of the CarboniferousPermian system are109094and-728_717respectivelyValues in Karst water of the upper part of the Ordovician(02f) are usually higher than those in Karst water of the lower part of the Ordovician (02f+m)from the same drill hole，which indicates that upper Karst water in deep places is recharged by overhead water bodies with a high level of isotopes (compared with the number of isotopes in Karst water) or waterbearing strata44 Distribution characteristics of radio isotopes In a horizontal direction，the residual volume of 3H in eastern Karst water is significantly larger than that in the west with a difference of one order of magnitudeThe volume of Karst water deep in the mining area is usually below 2 TU，which indicates that its leakage path is long and the age of groundwater increases In this section，from pore water ofthe Quaternary system and fissure water of the CarboniferousPermian system to Karst water of the Ordovician，the residual volumes ofH become smallerThis difference in residual volume exists even between the Fengfeng and the Majiagou FormationsThe residual volume ofH in groundwater of the same stratum is also higher towards the east and lower towards thewest，while that for both precipitated water and surface water is consistentThese difrerences indicate that groundwater receives its recharge from rainfall and surface water through leakage(from top to bottom)and its age increases with a much smaller leakage velocity in the west than that in the east.5 Conclusions 1)The recharge source for Karst water deep in the mining area comes from water in the higher western mountain areas through vertical leakage，which is proven by the differences in water levels of each stratum，their stable isotopes and residual volumes of 3H 2)In a horizontal direction，Karst water flows along the antidip from a deep，stagnating flow area where the amount of water is small, to a strong runoff area in shallow places which contain abundant waterThe leakage coefficient and the amount of leakage both increase from west to east and the recharge source of Karst water becomes fresher when the age of the mixed water decreases 3) The main channels for vertical leakage and horizontal runoff are neotectonic fractures which connect deep and shallow parts of the mining area The fact that their mixed water is fresher than the surrounding water shows that the recharge and runoffconditions are ex