Tunneling in abandoned coal mine areas: Problems, impacts and protection measures

• Conceptual intersection models and risk assessment methodology for tunneling in abandoned coal mine areas.
• Recommendations for remedial measures for tunnel construction in abandoned coal mine areas.
• A flow chart for assessing support requirements in abandoned coal mine areas.

The tunnel design and construction in abandoned coal mine areas confront many challenges. Because of the historical reasons as well as complicated geologic and mining features, it is difficult to track and predict the locations, dimensions and geometry of the abandoned mine workings. The typical problems during the construction are always related to residual voids, mine water, infillings and gases. In this paper, a series of conceptual intersection models for risk assessment are discussed, and each model is characterized by a combination of tunneling problems. This paper also presents a risk assessment methodology, which links various intersection models to potential geo-hazards. A discussion on the engineering solutions in order to cross abandoned mine workings is also presented. Based on lessons learned from case histories in China, a flow chart for assessing support requirements in abandoned mine workings is proposed. Therefore this paper provides a framework to assess and reduce the geo-hazards associated with tunneling in abandoned mine areas and some applicable remediation techniques are proposed.