The project is about the investigation of reliability of the dumper and its availability throughout the year. At first the trend analysis performed for the understanding of the failure behavior of the dumpers. It will make an arena for the further analysis and investigation over the dumpers to know its reliability component and availability assessment. Further based on the outcomes of the reliability and availability with reference to the bath tub curve the maintenance policy formulation can be done. In this work the trend analysis have used the following tests namely: eye ball test , cumulative plot test, serial correlation tests and karl pearson coefficient of correlation tests. So based on these outcomes the non homogeneous poison models have been chosen to find out the reliability and availability. As a part of that the maximum reliability is obtained for the dumper-2019 as 83.8% and lowest reliability is obtained for the dumper-2018 i.e., 47.8%. Similarly the availability of the dumper is found to be maximum for dumper 2018 i.e., 58.35% and the lowest availability is observed for dumper 2019 i.e., 31.3%. With above investigation & results it is concluded that the dumper performance as per the bath-tub-curve is in the third or declining stage but there is a supportive thing about it is its availability is improving hence the condition based and corrective maintenance will certainly uplift the reliability of dumper. As a last option the replacement of the elements of the dumper are advised.