The Evaluation Of Ore-Rock’s Blastability In Metal Mine And The Theoretical And Experimental Study Of Deep-hole Blasting Parameters’ Optimization In Underground Stope

Characterized by large diameter borehole blasting, underground deep-hole mining technique is a large-scale and high efficient technique applied in major underground mines which has high mining intensity and high productivity. The blasting parameters often originate from experience and engineering analogy analysis, which is not quite scientific and systematic. The thesis based on the Science and Technology Innovation Project of Yunnan Province named "the Industrialization and Key Techniques Study of Kafang Tungsten Polymetallic Ore Development and Utilization" trys to apply "Mining Environment Regeneration and Continuous Mining with Subsequent Filling Mining Method" and deep-hole blasting technology in test mine and in order to reach the set productivity target. The thesis focuses on the theoretical and testing research of parameter optimization for deep-hole blasting under the condition of mining environment regeneration. The main research contents are as follows:(1) Combining environment reconstructing technique and the design and optimization of deep-hole blasting parameters, the thesis investigates the geological structure of test mine and gathers statistics on joint fissure. Then it takes indoor experiments to test the physical and mechanical properties of mine rock and evaluate the rock quality of the test mine.(2) The blasting crater test has been done based on Livingston theory. The mine rock similar to the test mine has been chosen to take on single-hole blasting crater tests and variable distance multi-hole simultaneous blasting crater test. The blasting parameters of deep-hole blasting test mine have been determined preliminarily, namely the interval of holes is2.0m, the distance between two rows (minimum resist line) is2.3m, and the unit explosive consumption is above0.57kg/m3. VC++6.0is used to establish a calculation program for blasting crater volume to reduce the workload.(3) The blasting parameters’s prediction model based on Rough Set and BP Neural Network is founded to testify and optimize the main parameters of blasting test experiment. It is assumed that the prediction model based on Rough Set and BP Neural Network is more accurate than the prediction model based on BP Neural Network and the predicted optimum crater radius is close to the experimental result, which proves the validity of blasting crater test. Excel2007and VBA language are used to design data discretization and normalization software based on Excel2007to process the sample data used in Rough Set which improve the efficiency.(4) Based on the data mining technology and on the basis of previous studies, the original rock blastability test datas’attributes reduction have been done by using rough set software, and the accuracy of reduction rules and KNN classification are verified. Based on the SPSS software, the calculation formula of ore-rock’s explosibility index is modified by using multiple nonlinear regression method, and the reliability of the modified formula is verified. The ore-rock’s blastability prediction model are set up respectively by single BP Neural Network and joint Rough Set and BP neural network, and the two kinds of models’ precision are compared, the study conclusion is that should give priority to the latter. The calculation results of the rock blasting index and explosive level in the test mine have been made by the modified formula and the results of calculation and evaluation are verified by the Rough Set and BP Neural Network prediction model, the final underground stope’s estimated value of blasting explosive unit consumption is0.62kg/m3by using empirical formula.(5) LS-DYNA is applied for numerical simulation analysis of test mine’s backfill’s security and stability in deep-hole blasting process and implements parameter argumentation. According to the different depth of pre-splitting crack, the7kinds of maximum initiating section blasting models are established, and the fill pillar’s vibration amplitude and stress intensity are analyzed and the fitting curve is gotten by the obtained data based on the principle of least square method, the optimized pre-splitting length is12.0m. On the basis of the previous research, the near point initiating section blasting models are established and analyzed, and the study show that the millisecond minute difference which defers time is longer than35ms between the main blasting holes. (6) Based on the main blasting parameters obtained by theory and experimental method, the deep-hole blasting experiment has been done in the test mine and the TC-4850blasting vibration monitors are used to monitor the main protected object in real time in which blasting vibration attenuation law is achieved and vibration signal and energy are analyzed through wavelet analysis.