Multisource Seismic Full Waveform Inversion of Metal Ore Bodies

The seismic exploration method could explore deep metal ore bodies (depth > 1000 m). However, it is difficult to describe the geometry of the complex metal ore body accurately. Seismic full waveform inversion is a relatively new method to achieve accurate imaging of subsurface structures, but its success requires better initial models and low-frequency data. The seismic data acquired in the metal mine area is usually difficult to meet the requirements of full waveform inversion. The passive seismic data usually contains good low frequency information. In this paper, we use both passive and active seismic datasets to improve the full waveform inversion results in the metal mining area. The results show that the multisource seismic full waveform inversion could obtain a suitable result for high-resolution seismic imaging of metal ore bodies.

Monitoring analysis and environmental assessment of mine subsidence based on surface displacement monitoring

Over the past several years, a metal mine by block caving method has experienced a long-term and progressive surface deformation and fracturing, and then we start our investigation based on this background. The location of surface rupture was based on a series of mapping activities and the deformation data was collected by GPS from 2013 to 2016. In this paper, emphasis was put on the analysis of the fissures, deformation and stress of surface subsidence. Results reveal the diversity magnitude and structural features of surface deformation and ground fissures. In addition, the time dependent behavior is comprehended and the subsidence zone reflects different types of time-displacement curve – regressive phase, steady phase and progressive phase, all these achievements indicate the complexity and diversity of the subsidence zone. On the other hand, stress calculation which inspired from the mechanical model of the cracking of hole wall is carried out, it is meaningful to understand the relation between fracture features, displacement vectors and horizontal stress.

Numerical Simulation of Cracking Failure and Weakening Law of Roadway Surrounding Rock under High Stress

In deep roadway mining, high water pressure causes rock mass cracking and weakens the overall strength, affecting the stability of underground metal mine mining roadways. Therefore, using a numerical simulation method, we analyzed the strain softening characteristics of rocks after the inflexion point of elasticity and studied the strain distribution and the minimum support resistance under high-pressure groundwater conditions. Considering the groundwater pressure and effective porosity on the strain softening characteristics of the surrounding rocks, we investigated the critical groundwater pressure under which the surrounding rocks would remain stable. Actual engineering verification helps to obtain the supporting characteristic curves under different influencing factors. We found that water pressure and effective porosity are the significant factors that decide the development scope of the plastic zone. The more significant the increase of the plastic zone, the more notable the changes in the support curve. Moreover, the plastic zone is likely to occur when the hydraulic head is between 30 and 50 m; when the hydraulic head exceeds 50 m, it is likely to produce a relaxation zone.