Morrison, KF, Johnson, JM, Augello, AJ & Doughty, B 2010, 'Innovative expansion of a large centreline constructed tailings storage facility in a seismically-active area', in R Jewell & AB Fourie (eds), Mine Waste 2010: Proceedings of the First International Seminar on the Reduction of Risk in the Management of Tailings and Mine Waste, Australian Centre for Geomechanics, Perth, pp. 205-215, https://doi.org/10.36487/ACG_rep/1008_18_Morrison (https://papers.acg.uwa.edu.au/p/1008_18_Morrison/) Abstract: The Bruno Creek Tailings Impoundment, located in seismically-active central Idaho, United States of America, retains tailings behind one of the tallest centreline-raise cyclone tailings sand dams in the world. From a current height of approximately 170 m, the dam is proposed to be raised to a height of nearly 230 m based on projected life of mine (LOM) ore reserves. An alternatives evaluation indicated the preferred option for tailings expansion is to raise the existing facility using the centreline raise method over most of the dam alignment, but modifying the design to employ a partial realignment of the dam crest at the left abutment. This change will result in a length of the previously centreline-raised dam being constructed over an existing tailings beach. The design also includes steepening of the downstream dam slopes, as well as construction of a raise on the existing rock toe dam to limit downstream impacts. This paper presents the geotechnical design aspects of the project, focusing on the site seismicity and assessment of dynamic liquefaction potential.