Filters provide defence against internal erosion in embankment dams. Natural sand sources with suitable quality for filter construction may be limited on the site, creating interest in alternative materials. This paper reviews current filter design principles for embankment dams, including the no-erosion filter concept, and examines the application of coke as an internal filter material for oil sands mining dams. The study builds on earlier work by presenting additional laboratory testing and field observations relevant to evaluate filter performance and constructability. Slot erosion tests at expected service hydraulic gradients were undertaken to assess compatibility of the coke with various materials, including low-grade oil sands and Clearwater Formation soils. The results indicate that, if the coke is screened to a specified gradation, it may be suitable as a filter under the conditions evaluated for low-grade oil sands / interburden and for silty non-dispersive Clearwater Formation (Wabiskaw member), but it showed marginal to unsuitable performance for the dispersive Clearwater Formation clay. Triaxial compression testing indicated limited particle crushing under expected static dyke loading, while field placement trials showed that excessive construction traffic on the filter can locally degrade the material and alter filter gradation. The study indicates that screened coke provides effective filter performance under the conditions evaluated when properly screened to a specified gradation, validated through laboratory testing under expected field conditions, and placed under rigorous construction quality assurance and quality control procedures.