1 geological overview
Xinqiao mine is located in the middle of the Yangtze Taiwan Pass, Tongling Fanchang fault-fold belt to the southern section of Tongling to wear the home of Central fault block area, the Yangtze River is an important metallogenic belt in mineral deposits.
There are two groups of faults in the mining area, one is a nearly parallel inter-layer fracture zone, and the other is a north-west transverse fault perpendicular to the anticline axis.
The magmatic rocks in the mining area mainly include the Iwate rock series, followed by the Niushan rock branches.
The Jutou rock strain is distributed in the middle of the deposit, and the plane is like an elliptical shape with an area of ​​0.3km2. The surrounding and surrounding rocks are curved and steeply contacted. In the strata surrounding the rock strain, there are rock branches extending, especially in the southeast, corresponding to the limestone layer forming a gentle tongue-like extension, which is in contact with the surrounding rock, forming part of the primary and secondary ore bodies. Top floor. The rock mass is clearly separated:
The central phase is dominated by quartz diorite , the transition phase is dominated by diorite, and the marginal phase is dominated by diorite. Niushan rock branches are distributed near the No. 2 pyrite ore body in the western part of the deposit, invading along the F3 fault, cutting off the nose of the Dachengshan anticline, and the plane is northwest and turns to the northeast. The length is about 800m. The rock branches are mainly composed of quartz. The diorite is composed of a part of the diorite. Other sporadic diorites distributed in a plane or section have a spatial relationship with the above-mentioned rock or rock branches.
2 West Wing - below 270m structure and stratum
2.1 West wing - below 270m structure
The area is located in the “knee-shaped†curved part of Xinqiao Mine. The ore body is thicker, mainly formed in the Chuanshan and Huanglong Formations, and a small number of ore bodies are formed in the Qixia Formation. The bottom of the ore body is the Gaochunshan Formation, and the top plate is a diorite body. The contact zone with the rock mass produces skarnization, and the contact zone skarn is relatively broken. In some areas, veins are inserted into the interior of the ore body.
(1) The interlayer slippage and fracture zone in this area is similar to the stratum, which occurs between the lower part of the Maokou Formation and the Gaochunshan Formation, and becomes the main part of the ore body, so that the Huanglong Formation is completely missing in some parts or Be confessed. There are obvious between the slip layer occurs with broken bits Chihsia layer, such as a position or magmatic occupied, the presence of copper or of iron sulfur spatial silver gold ore.
(2) There are many faults in this area, one of which has a fault, passing through the W301, W403, W505 stope, tentatively designated as fault No. 1. In addition, in each stope, there are still many small faults that traverse the ore body along the stratum or tend to longitudinally cut along the stratum.
2.2 West Wing - below 270m stratum
The west wing - below 270m exposed to the northwest, tends to the north east, about 30 ° in the eastern part of the dip, about 10 ° ~ 20 ° in the west. The top of the ore body is mostly skarn, which is about 10-20 m thick and is distributed on the contact zone between the ore body and the diorite. The exposed strata are from bottom to top:
(1) The exposed rock formation in the Upper Devonian Wutong Formation (D3w) is mainly quartz sandstone , which is partially silicified and has pyrite mineralization in the rock formation;
(2) Lower Carboniferous Gaochunshan Formation (C1g) sandy shale with thin layered clay shale, medium-thick layered quartz sandstone and quartzite , thickness 10~30m;
(3) The Middle Carboniferous Huanglong Formation (C2h) thick layered limestone, dolomitic limestone, dolomite , and 0.1-0.8m quartz fine conglomerate at the bottom, 30m thick, is an important metallogenic horizon, most The lot is occupied by the ore body and the local marble is calcified ;
(4) The Upper Carboniferous Chuanshan Formation (C3c) thick layered limestone, 60m thick, is one of the important metallogenic horizons, and some sections are occupied by ore bodies, localized lithology;
(5) The Lower Permian Qixia Formation (P1q) thick layered asphaltic limestone, suture limestone, thick layered meteorite nodules, is the secondary metallogenic horizon.
3 West wing - below 270m ore body characteristics
The ore body below the west wing -270m is mainly the No. 1 ore body, and the ore body is annihilated downward. At -320m, it is divided into east and west ore bodies, in which the eastern ore body is completely annihilated at -370, and the western ore body is divided into two ore bodies at -360m. The lower the extension, the narrower the ore body becomes, and gradually Divided into a number of small ore bodies. The main types of mineral ore pyrite, pyrite copper, copper-containing magnetite, and a small amount of lead zinc ore. In addition, it contains considerable secondary gold and silver ore bodies in the ore.
3.1-300m middle section ore body characteristics
The middle part of the -300m ore body is gripped by a fist. The ore body is enriched by copper deposits at the bottom plate; the middle part of the ore body has more magnetite content; the bottom plate is pyrite. The ore body belongs to a polymetallic deposit. In this middle section, the ore body contains 5.98 million tons of copper-sulfur ore and 4.17 million tons of magnetite, which contains 15 tons of gold metal, 130 tons of silver and 50,000 tons of copper (see Table 1).
(1) In the middle of -300m, the ore body gradually becomes narrower and the ore body shape becomes slower.
In the W601 stope, the ore body is divided into two ore bodies, and the main ore body becomes extremely narrow, about 20m wide. However, when the W703 is used, the ore body is an ore body, and the width of the stope is widened to about 40m. From W703 to the west ore body, it is divided into two. One of them saw a small amount of pyrite secondary products at the bottom of the river, and a pyrite secondary product was seen near the roof, which was about 10 m wide. There is a section of fresh rock wall in the ore body, which is inserted into the ore body through the junction of W603 and W604.
(2) In the northern top of the ore body, 50m ore body is exposed, but the actual stope only has the W301 stope to the top rock roadway, and the other stopes are not collected. At the same time, according to the W505 stope ZK2703 drilling It can be seen that there are still some ore bodies at the front end, but the 15m rock mass has actually been drilled, and no ore has yet been seen. In the second layer W301, W403 stop, there is a fault No. 1 across the stop. Therefore, it is speculated that there is a near-east-west fault cut at the northern end of the stope, causing the northern ore body to slide westward.
(3) In the eastern part of the ore body, there are many rock masses in the middle of the ore body, mainly appearing in the boreholes ZK2608 and ZK2406. However, the eastern ore body has not yet fully developed, so the location of the ore body may be biased. The ore body at this site can be further drilled after the end of the -270 east expansion project.
Ore body characteristics below 3.2-300m
Below -300m, the ore body gradually shrinks. The -320m ore body is completely disconnected and exists in the form of two ore bodies; when it reaches -370m, the eastern ore body has been annihilated, while the western ore body still exists in the form of a lens and extends to -580m.
(1)-330 The middle ore body exists in the form of a dumbbell. At -320m, the ore body is divided into two pieces. The magnetite in the ore is reduced by about 1.15 million tons, and the rest are copper-sulfur ore, about 5.95 million tons (see Table 2).
(2) The ore body below -339m exists in two inclined inverted cones. The ore body of the north west extends down to -580m, and the ore body of the south east extends to -370m. The magnetite in the ore is about 725,000 tons, and the rest is about 3.03 million tons of copper-sulfur ore (see Table 3).
4 Influence of ore body characteristics on mining
The influence of the ore body characteristics of the middle section of 4.1-300m on mining
According to the characteristics of the ore body of the W601 stope in the middle of the -300m section and the W703 stope, this part of the ore body is prospected.
(1) In the W601 stope, first drill a prospecting lane along the direction of the ore body, and then prospect the mine. According to the specific conditions of the ore body, the stope is arranged, which can optimize the layout of the stope.
(2) At the forefront of the W703 stope, the No. 2 prospecting alley is headed north to find the northern ore body. In the west, in the west, because there is no drilling, you can only refer to the ore body in the -300m roadway and the appearance of the exposed rock. The shape of the ore body can be inferred. Direct mining to the west.
At the northern end of W301~W403, the top rocky alley sees the mine, but except for the W301 stope, the other stope is not collected. This is mainly due to the fault cut-in, resulting in some ore bodies not being mined.
Therefore, it is recommended that this part of the ore body be considered for mining the unmined body when mining the column.
Due to the complex and variable shape of the ore body, the geological data may be biased, which makes the individual sections unreasonable when designing the roadway of the stope. In the E105～E206 stope, there are two stratifications. Because the roadway is too close to the stope, a small part of the ore body in the upper part of a stratified main road cannot be mined for safety reasons. At the same time, it is in the W103~W405 stope, because the alley is away from the stope. Too far, the average distance is about 40m, which leads to long road intake, increased tunneling cost and mining cost.
In the W603~W605 stope, there is a rock wall cut in. In the north of Lianxiang, the rock wall is just in the middle of the two stopes of W603 and W604. This part of the rock wall can be used as a natural pillar to increase the safety of mining. On the south side of Lianxiang, the rock wall is just interspersed with the W604 stope. This part of the rock wall can be used as part of the filling material to fill the stope that has been completely emptied, which can reduce the lifting pressure of the measure well and reduce the transportation cost and filling cost.
Influence of ore body characteristics of 4.2-330m on mining
Specific issues are specifically analyzed during mining. In the shovel to a layer, the stope can be arranged less, two or three layers, and more layout.
During the construction of the middle section of the -330m, the bottom of the ore body is too far away from the bedrock tunnel. The floor of a layer of ore body is about 100m away from the main roadway, and the floor of the three-layer ore body is about 60~70m away from the main roadway. Therefore, it is proposed to modify some areas of the bottom rock roadway, which will not only reduce the cost of roadway excavation, but also make it easier to mine later.
5 Conclusion
(1) The middle of the 300m middle ore body also has mining value. The W703 stope has a stratified ore of about 10,000 tons, the western one layer can mine no less than 40,000 tons, and the sulfur taste is about 34%. And the higher the ore body, the more it can continue to mine.
(2) The middle part of the -300m ore body is greatly affected by the fault. The large fault in the middle part cuts through the stope in the vertical direction, and the northern part of the stope is cut off, resulting in a small part of the ore body temporarily being unexploited.
(3) The middle section of the -300, -330m ore body is too far away from the main road in the horizontal direction, which will definitely cause a lot of trouble for subsequent mining. Therefore, it is recommended to optimize the individual lanes of the main lane according to the design drawings.
references:
[1] Chen Bin, et al. Xinqiao Mine 2007 Annual Reserve Report [R]. Tongling: Tonghua Group Xinqiao Mining Co., Ltd., 2008.
[2] 803 Geological Team. Xinqiao Mine 1971 Reserve Report [R]. Ma'anshan: 803 Geological Team, 1971.
[3] 321 Geological Team. Xinqiao Mine 1991 West Wing Encryption Exploration Report [R]. Tongling: 321 Geological Team, 1991.
[4] 321 Geological Team. Gold and silver mine report [R]. Tongling: 321 Geological Team, 1995.
[5] 321 Geological Team. Reserve review report [R]. Tongling: 321 Geological Team, 2005.
[6] Li Jiaojiao. Geological characteristics and ore-controlling geological factors of Cu-S-Au polymetallic deposit in Xinling, Anhui Province [D]. Wuhan: Wuhan University, 2012.
Superb; Changsha Institute of Mining Research Co., Ltd., Changsha 410012;
Source: Mining Technology: 2016.16(5);
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