2.1. Visual examination Fig. 1 (A and B) shows the location of leakages on the coal ash slurry pipeline in two different areas. Fig. 1B shows the cut portion of same failure pipeline considered for the present investigation. The pipeline which had failed was inspected and a large crack (hole) was observed. A small portion of the pipeline with failure region crack (hole) (Fig. 1(B)) was cut along the two cutting lines and observed with naked eyes. The external and internal surface had oxide scale over it branching at the subsurface. In addition to that several localized pitting and ploughing attacks were observed in inner top and bottom surface of the pipeline respectively as shown in Fig. 1C. This is because of large size and mass of coal ash particles which comes in contact with the bottom inner surface of the pipeline when coal slurry is flowing through the pipeline. Similarly, the top inner surface mostly comes in contact with air bubbles which have occurred due to variation in particle size, shape and temperature of ash particle flowing through the pipe.