The Legacy of the Past: Geotechnical challenges from coal mining impacting major rail infrastructure.

The legacy from a long history of mining, quarrying and subsequent landfilling can present significant geotechnical challenges to infrastructure schemes. When upgrading existing rail lines through congested urban corridors there is little opportunity to avoid the risk. Understanding the legacy of the past and the risk posed to the construction and operation of both existing and new track and structures is key to building resilient structures and a sustainable railway for the future. The paper discusses how the coal mining risk was managed and through dialogue with Network Rail a balanced approach (considering safety, cost and resilience) was adopted to determine appropriate mitigation. It then discusses the challenges implementing drill and grout mitigation in a live rail environment, around buried infrastructure, through landfill areas and adjacent to water courses. All required as mitigation for a new flyover and viaduct structure between Huddersfield and Dewsbury.