GPR based RTM imaging technology for estimating rhizome diameters and application in the western China mining area

The rhizome functions are of great significance to the ecological protection of the western China mining area,whose ecological management can be provided with technical support via accurate calculations of the rhizome biomass.The rhizome diameter is an important index parameter of rhizome biomass.In this study,we propose an estimation of rhizome diameters based on ground penetrating radar(GPR)-based reverse time migration(RTM)imaging technology.First,the spatial distribution of shallow rhizomes is simulated using the finite difference time domain method.The simulation data are examined via RTM imaging and single-channel rhizome analysis to obtain the rhizome index parameters:Δh,the width of the maximum positive peak amplitude measured at an amplitude of zero,andΔH,the distance between the zero-amplitude position above the largest positive peak in the shallow region and the zero-amplitude position below the largest positive peak in the deeper region.The experiments of physical models verify the effectiveness of the two parameters(Δh andΔH).and indicate that the values ofΔh andΔH are independent of the rhizome burial depth;instead,they are only related to the diameter of the rhizome.For both the numerical simulations and the physical model experiment,the estimation errors ofΔh andΔH for the rhizome diameters can be constrained to less than 6%and 5%,respectively,which shows that the estimation of the rhizome diameters using GPR based RTM imaging technology is reasonable and effective and its high estimation accuracy meets the technical requirements.

Technology Development and Engineering Practice for Protection and Utilization of Water Resources in Coal Mining in Western China

Shanxi,Shaanxi,Inner Mongolia,Ningxia,and Gansu(hereafter generally referred as "the Western Area")are major coal-producing areas in China due to rich coal resources and good mining conditions.However,the Western Area has a serious water shortage.The surface evaporation is huge and a great amount of mine water generated in coal mining is evaporated and lost after discharging to surface.In order to protect and utilize the water resources during large-scale coal mining in the Western Area,Shenhua Group has put forward a technological idea to store mine water in underground mined areas and successfully researched and developed the coal mine underground reservoir technology by solving the technical difficulties of water source prediction,reservoir site selection,reservoir capacity design,dam construction,safety guarantee,water quality control and so on through20 years of exploration.Now Shenhua Group has successfully established a batch of reservoir in the Shendong Mining Area,obtaining great economic and social benefits.The technology is also extended to other western mining areas,providing an effective path for harmonic mining of coal and water resources in western China.