Ice pigging is an innovative pipe cleaning and product recovery method, patented at the University of Bristol. An ice pig is formed from an ice slurry, which is a two phase mixture of ice crystals suspended in an aqueous solution, most commonly brine. The process involves the flow of ice slurry through a pipe network, driven by a positive pressure differential. The process is capable of effectively removing fouling from internal pipe walls, and recovering product that would otherwise be wasted, in situations where conventional pigging is impossible or impractical. Ice pigging is becoming the worldwide industry standard cleaning technique in the water industry, and is also used for a range of further applications in many industry sectors. Additionally, it is being developed for nuclear and hydrocarbon applications. This thesis investigates the determination of ice fraction , which has been shown to be the critical ice slurry characteristic upon which the performance of an ice pig depends. However, existing ice fraction diagnostic processes are limited, either by inaccuracy or process practicality. Research set out addresses these flaws , and proposes two new ice fraction determination techniques. The first is an improvement to the existing cafetiere test, which is used primarily as a rapid, low cost approximation method. The second is ice fraction determination through electromagnetic interrogation. Development of this process included in-line investigations and the development of a salinity calibration technique. The complete process provides an in-line and near instantaneous ice fraction prediction, shown to be as accurate and reliable as the current gold standard, calorimetry method, which was used to monitor the performance of this novel technique during experimental work. This thesis concludes with a discussion regarding the simplification of the process, shown to not significantly increase process error, and the design of a testing component fit for industrial use.