Research On Source Determination Of Mine Water Inrush Based On Laser Induced Fluorescence Technology

In the development of national economy, coal occupies an important position. About 95% of coal production are from underground mining in China, and as time goes by, shallow coal mining are exhausted, many mines gradually developing in depth, which was followed by harsh hydrogeological environment, and a vast territory, diverse geological structure, resulting in coal mine water inrush probability and risk also increases. At this stage to the mine water inrush prevention using a combination of several techniques:1, the geological exploration technology, obtain hydrogeological structure, to avoid dangerous water in advance; 2, water source determination technology, obtain the source of aquifer or water inrush, to determine the distribution of groundwater or assess risk of mine water inrush; 3, water parameters real-time monitoring technology, obtain the parameters such as water pressure, inflow, conductivity, so as to realize the real-time monitoring and early warning of water inrush. In the three technology, analysis of hydrogeological structure in the late of the geological exploration technology need the support of water source determination technology, in view of the occurrence of water inrush, water parameters real-time monitoring technology is useless for water inrush warning. Therefore, How to determine source of the mine water rapid, it is of great significance for no matter research or prevention of geological disasters, and hydrology mine water inrush. And the current technology in the actual production of coal mine also has the following disadvantages:1, Have a high level dependence on the hydrogeological and tectonic survey data; 2, It’s difficult to find out the relatively small water structure; 3, Water source determination is given priority with chemical methods, which takes a long time(1-2 hours), and the accurate rate is relatively low,4, Most of the equipment adopt mechanical sensor or resistance sensor, which need explosion-proof processing, and have a poor performance on anti-interference.For this situation, we proposed a new rapid source determination of mine water inrush method which based on the laser induced fluorescence(LIF) technology, using different coal mine water aquifers as the research object, by getting different fluorescence spectral information of the coal aquifer water, build the water spectral database of inrush water, which as a basis to build the rapid source determination model of mine water inrush. The entire system can cost only few seconds to complete the rapid source determination of mine water in case of a complete database, which laid the theoretical and technical basis for the further development of laser-induced fluorescence techniques to source determination model of mine water inrush, thus achieve the coal mine safety production, and to provide rapid discrimination basis for the mine flood relief The main results and conclusions are as follows:(1) According to optical principles and characteristics of the coal mine, built the rapid source determination system of mine water inrush based on laser induced fluorescence which is suit for the coal characteristics, and designed the corresponding intrinsically safe power supply, developed the rapid source determination software of mine water.(2)Using the ordovician limestone water, old kiln water, alluvium water, sandstone water and limestone water collected in Xinji mine of Huainan as experimental subjects, established the rapid water source determination model based on SIMCA and PLS-DA In SIMCA model, the original spectral by Gaussian-Filter pretreatment, under the condition of the principal component number is 2 and the significant level α=5% to classify the water inrush samples in calibration set, the accuracy of 5 kinds water models to the water samples are all reached 100%, which to the water inrush samples in validation set, the accuracy of 5 kinds water models to the water samples also are reached 100%. In PLS-DA model, established 5 kinds of water samples PLS-DA model in accordance with the principles of PLS, the accuracy of all kinds water models in calibration set are all reached 100%. The correlation coefficient r successively reached 0.976,0.996,0.982,0.971, 0.993, RMSECV successively reached 0.087,0.040,0.073,0.079,0.047; The accuracy of all kinds water models in validation set are all reached 100%, which RMSEP successively reached 0.116, 0.054,0.089,0.123,0.061, which indicated the LIF technology combined with PLS-DA model can be used to rapid source determination for Xinji mine of Huainan.(3) Using the old kiln water, sandstone water and alluvium water collected in Yanzishan mine of Datong as experimental subjects, verified the rapid water source determination model based on SMCA and PLS-DA. In SIMCA model, the original spectral by Moving-Average pretreatment, under the condition of the principal component number is 2 and the significant level a= 5% to classify the water inrush samples in calibration set, the accuracy of 3 kinds water models to the water samples are all reached 100%, which to the water inrush samples in validation set, the accuracy of 3 kinds water models to the water samples also are reached 100%. It verified that LIF technology combined with SMCA is useful for rapid source determination of mine water. In PLS-DA model, established five kinds of water samples PLS-DA model in accordance with the principles of PLS, the accuracy of all kinds water models in calibration set are all reached 100%. The correlation coefficient r successively reached 0.997,0.991,0.987, RMSECV successively reached 0.037,0.065,0.069; The accuracy of all kinds water models in validation set are all reached 100%, which RMSEP successively reached 0.062,0.093,0.151, which verified 1hat LIF technology combined with PLS-DA is useful for rapid source determination of mine water.(4) Based on the water rapid source determination model of mine water, combined with the water inrush instance, established a mine water inrush warning model. Using the water samples collected in Yanzishan mine of Datong as experimental subjects to verify the model, based on the SIMCA and PLS-DA model established and alluvium water & sandstone water, old kiln water & sandstone water and a normal water samples of sandstone water to rapid source determination of mine water. In SIMCA model, the original spectral by Moving-Average pretreatment, under the condition of the principal component number is 2 and the significant level α=5%to classify the water inrush samples in calibration set, the accuracy of 3 kinds water models to the water samples are all reached 100%, which to the water inrush samples in validation set, the accuracy of 3 kinds water models to the water samples also are reached 100%. It verified the feasibility that LIF technology combined with SIMCA is useful for rapid source determination and early warning of mine water. In PLS-DA model, established five kinds of water samples PLS-DA model in accordance with the principles of PLS, the accuracy of all kinds water models in calibration set are all reached 100%. The correlation coefficient r successively reached 0.992,0.989,0.985, RMSECV successively reached 0.041,0.073,0.087; The accuracy of all kinds water models in validation set are all reached 100%, which RMSEP successively reached 0.075,0.108,0.197, which verified the feasibility that LIF technology combined with PLS-DA is useful for warning of mine water inrush.(5)Compared the result with SIMCA and PLS-DA model for mine water source determination, it can found that they all have a better determination to the water sources, but relatively, PLS-DA model has a higher discriminatory power, and without the need for spectral pretreatment which the step is relatively simple.Integrated use of the technical conclusion of this study, constructed the rapid water source determination model, used the water samples in Xinjin mine of Huainan and Yanzishan mine of Datong to test and verify the classification modeL Get fluorescence spectral of water samples by LIF system, through spectral pretreatment to analyze the data, then fluorescence spectrum will be treated to the classification model, which could determined the source of the mine water and have a assessment on the risk of the mine water inrush. Construction of the model is of great significance for controlling and preventing water inrush, the equipment which developed on the basis of the model has been applied to several coal mines as a part of water inrush monitoring and early warning system, economic and social benefit is remarkable.