The Atkinson equation along with its friction factor is commonly used to estimate pressure requirement in mine ventilation. However, friction factor correlation of flow through broken rock, typically found in blasted stope, gob, rock pit or block caving rock deposits, etc., is currently unavailable. Also, it is imprac-tical to conduct direct measurements of flow resistance in an inaccessible broken rock zone. This paper aims to develop a new friction factor correlation of flow through broken rock that can be used directly in Atkinson equation. The proposed correlation is valid for broken rocks with diameter between 0.04 and 1.2 m and porosity ranging from 0.23 to 0.7.