| The Wenshan Guanfang Tungsten Mine is located in Xiaojie Township Wenshan County in Yunnan Province. Through detailed mining area investigation, we have discovered that it is a medium-sized ore deposit. The ore type of this mining area is skarn scheelite. According to the mine owner's planning, its capacity is 60,000 tons yearly. It has already reached medium-sized ore deposit. The mining prospect is rather considerable. At present, a great deal of mining areas at home and abroad lack hydrogeology survey. The mine water calamity always happens during mining. In order to take measures in time, it is very necessary to make a hydrogeological investigation in Guanfang Mining area.The main study area of this paper is Guanfang Mining area Tuanshan ore block in Wenshan. Tuanshan ore block is located in the southwest of Bozhu Mountain. The fracture structure development and the hydrogeology conditions in the mining area are rather complicated. In order to find out the hydrogeologic features of the mining area, the paper has carried out research work as the following four aspects.(1)Firstly, this paper makes a research in areal geology and hydrogeologic features.①The research area is located in the southwest of Wenshan county, which is in southeastern Yunnan Province. The landform of this area is formed after high land eroding valley. The terrain slopes sharply. In general, it is higher in the north and lower in the south. The transport is rather convenient. The electric power resources are adequate, which can satisfy the living and production need of the mining area.②The paper has found out that the main exposure strata are D1p,O1,∈3b—∈2l,∈2t,∈2d,∈1ch andηγ53(a). The fracture and fold in this mining area have developed. The faulted structure plays the main part. The fold is mainly Bozhu Mountain dome structure. The faults mainly consists three groups:NW, NE and nearly EW direction. The main structural line is NE direction. The magmatic rock of this district is mainly granite intrusion in Bozhu Mountain. There are also few diabase and gabbro.③The groundwater types in this mining area are pore water, fissure water and karst water. According to formation lithology, karst fissure development and stratum watery, this paper has divided this mining area into six aquifer and aquifuge groups:pore aquifer of loose ground water-bearing formation(Q), clastic rock weathering crack water-bearing formation (D1p,O1), carbonatite karst weathering crack water-bearing formation (∈3b—∈2l), carbonatite and clastic rock karst weathering crack water-bearing formation (∈2t,∈2d), metamorphic rock weathering crack water-bearing formation (∈1ch), granite weathering crack water-bearing formation (ηγ53(a)).④A complete geohydrologic unit should possess independent supply-passage-discharge relationship, according to the principle, this paper divides the whole mining area into two parts:geohydrologic unit I and geohydrologic unitⅡ. The ground water receives recharge from the boundary of cretaceous granite and Cambrian marble. The mining area is located in the supply-runoff district of geohydrologic unitⅠ. Besides, it also drains through the way of spring falling in the south of the mining area.(2) This paper analyzed geothermal feathers and its influence on the mining area. There are three springs outcropped in this area. They are Changputang spring, Yaodianhe spring and Erhegou spring. The three springs distribute uniformly from NW to SE. The length is seven kilometers. The springs outcrop from (ηγ53(a)) biotite adamellite. While eroding the bottom of ravine, the springs pour forth from diluvial layers and alluvial layers, in the form of flake. The outcrop area of the spring is located in the south of Bozhu Mountain's anticline. The fault and fold develop in this area. It is mainly NE faulted structure. The temperature, hydrochemical features, outcrop area's geological conditions and genesis of the three springs are similar, so the geothermal feathers of the three springs are the same. Since the discharge of Yaodianhe spring and Erhegou spring is little, it is difficult to get water from them. This paper used Changputang spring, which is easy to get water, as a sample to analyze the geothermal feathers and its influence on the mining area. This paper applied SiO2 geothermometer (Fournier,1981, proposed that there is no steam damage during the heat transport) and Na-K geothermometer to calculate the cycling temperature of the spring. The book Geologic Exploration Standard of Geothermal Resources recommends a calculation formula to calculate the spring's depth of round, and has received the spring temperature is 114.6℃and111.9Z℃. The error is rather small. The calculating result through the two ways is reasonable. According to geothermal degree, we can estimate the heating depth of ground water cycling. The formula of estimating depth of round (Wang Dachun,1986) concluded the spring depth of round is 2641. According to the method of milligram equivalent, while the percentage is big than 25%, zwitterion can participate in water's denominating. Yaodianhe spring should be dominated HCO3-Na+. Ground water of mining area should be dominated HCO3-Ca2+. The surface water of Yaodianhe should be dominate HCO3-SO4-Ca2+. The temperature of the spring is 46-53℃. The temperature of mining area's water is 17-21℃. Changputang spring and Erhegou spring outcrop far away from the mining area. The two springs outcrop from granite. They have no effect on the mining area. Yaodianhe spring outcrops along F3 fault. However, the NE F3 fault is compresso-shear fault. The rock mass of the fault is splitting. There is mud filing the fault. Besides, the fault has water-proof feature. For these above reasons, F3 fault cannot become the water conducted passage between the spring and ground water of the mining area. From the spring's depth of round, we can find that spring has the feature of deep circulating. There is a big difference between the water quality of spring and mining area. There is no permeable structure between spring and ground water. So we can find that there is no water conservation relationship between them. From the contrast of spring and ground water's temperature, we can learn that the ground water does not receive heating supply from the spring.(3) The result of studying the hydrogeologic condition of the mining area shows that: the mining area is located in the South of Bozhu Mountain's anticline. Fold structure develops in the mining area. In general, it is SSE monoclinal structure. The mining area is belongs to the relief of middle and high mountain eroding valley. There are mainly two surface rivers, Yaodianhe River in the west of the mining area and Erhegou River in the east of the mining area. The two rivers both emanate from the south of Bozhu Mountain. They flow from north to south along the border of the mining area and form a river in the south of it, which is called Namuguo River. Then this river flows towards the south into Nanxi River, and finally flows into Hong River. The fracture and fold develop well in the mining area. They are mainly NE fracture structure. The NE fracture is mainly compresso-shear fault, which has the feature of water-proof. According to the lithology of water-bearing formation, ground water geological condition, hydropower nature and character, this paper divided the water-bearing formation of the mining area into eleven groups. The quaternary system pore aquifer of loose ground aquifer (Q), the limestone karst cracks aquifer (∈2t4), the clastic rock fracture aquitard (∈2t3), the clastic rock fracture aquitard (∈2t2-2), the limestone karst cracks aquifer (∈2t2-1), the clastic rock fracture aquitard (∈2t1-3), the limestone karst cracks aquifer (∈2t1-2), the clastic rock fracture aquitard (∈2t1-1), carbonatite the clastic rock fracture aquifer (∈2d), the clastic rock fracture aquitard (∈1ch), the granite weathering fracture aquifer (ηγ53(a)).The mining area belongs to the supply-discharge district. The main orebody of Tuanshan ore block is located above local base level of erosion. Under the surface river of the mining area, the structure commonly does not develop. The wall rock of the ore body's roof-floor is skarn. The fracture of granite is aquitard. All the above matters are the main origin of deposit's water filling. Water can flow into the roof-floor of ore bed, however, the topography is not good for natural drainage. A preliminary study suggests that the hydrogeology condition of this mining area is one kind of water filling fissure ore bed with intermediate complicated water filling roof-floor.(4) This paper makes a prediction research of mine's water gushing. The calculating region chooses the north of the mining area, which makes the granite and marble's boundary of Bozhu Mountain as constant flow borderline. The south direction chooses Yingpan Mountain as constant flow borderline. The west direction chooses F3 fault as impervious boundary. Firstly, we should generalize the actual hydrogeological condition, and build a hydrogeololgy conception model. This thesis makes a prediction of mine's water gushing based on applying analogue method? ultimate spacing pattern method and numerical method. The analogue method adopted Guanfang ore block of this mining area as an analogy object. This paper chooses PD4 to measure its water yield, and uses the result as reference data to calculate. The ultimate spacing pattern method budget and resources estimate distribution range adopt ground surface drilling line to ascertain. It calculated the final lower limit is 1300m. The calculation formula adopts the ground water well formula to calculate the mine's water gushing. Firstly, the numerical method choose the boundary of the granitic mass and marble of the north Bozhu Mountain and the south Yingpan Mountain as constant flow supply borderline. The west direction chooses F3 fault as impervious boundary. This paper revised the model, and finally adopts two dimensional motion's partial differential equation and definite condition of ground water to simplify. It applies trimesh finite difference method to construct numerical model. After debugging and identifying the numerical model, the mine's water gushing has been calculated. The above three methods respectively studies the lithological characters of marble, skarn and hornstone, and mine the following five level developments:1400,1350,1300,1250 and 1200. Besides, the paper respectively calculate the mine's water gushing of the five level developments. A comparison has been made on the data, the error is 2.6%—15.1%. The paper has made a conclusion that the calculating result is reasonable. This method of analyzing the hydrogeologic condition of the mining area and the prediction of mine's water gushing has provided scientific basis for different quarry operation plan's designing and the development system's arrangement. Moreover, it provides the basis for the selecting of undermine drainage and the working out of water disaster preventing and controlling methods. |
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