Improved methods for prediction of mine water inflow and determination of accuracy of results

Being mindful of issues such as ambiguity in how to define and determine mine water inflow (including normal water inflow and maximum water inflow) and releasing water, the large gap between the predicted results and measured ones for mine water inflow and difficulty for refining results plus lack of consensus on the accuracy of predicted values, after reviewing currently available specifications and research results, we present triple attribute characteristics for mine water inflow: statistical attribute, hydrological attribute and production attribute, on the basis of which the basic definition of mine water inflow was discussed; The mine water inflow is generalized as the result of the joint action of the water filling source and the water filling channel, with special attention on the dynamic characteristics of the water filling channel and the recharge relationship between the aquifer and the mining space. This work analyzes the fine composition of water inflow and relevant calculation methods under “large well method”, and propose to employ “same frequency magnification method” to improve hydrogeological analogy method and obtain the predicted dynamic curve of water inflow; By combining time series analysis with hydrogeological analogy, the prediction step size (prediction periodic) increased and the applicability of time series analysis was enhanced. By reviewing the statistical differences existing in all specifications, literature definitions and the flood control practice in actual mines for the normal water inflow, the maximum water inflow and the predicted values for both normal water inflow, the maximum water inflow, it is concluded that there is lack of consensus on understanding the prediction results of water inflow and the present main issue posed in determining the accuracy in prediction of water inflow is neglecting the technical conditions .In this paper, we discussed two main methods for determining the accuracy of mine water inflow prediction, the “absolute difference method” and the “relative difference method”, proposed standards for how to classify water inflow prediction results into economic type, safety type and deviation type depending on main functions of mine water inflow prediction, the advantages and disadvantages of the two methods are discussed by comparison, and we concluded that the two methods should be combined in practical application for a accurate prediction of mine water inflow. By unifying the technical backgrounds, we could achieve the technical mutual verification on mine water inflow prediction, real water inflow statistics and determining the accuracy of predicted results, hence improve the technical system for mine water disaster prevention and control.