The present study investigates the feasibility and efficiency of river sand replacement with copper mine tailing waste as fine aggregate in cement mortar. The scope of the present study includes durability, microstructure, and morphology of mortar mixes created by different percentages replacing copper tailing. The study ranges from 0% to 50% by volume replacement levels of sand by CT with an interval of 10% in 1:3 (rich Mortar) mortars. The quantity of cement remains constant in all the mixes, and the amounts of fine aggregate and tailings are adjusted properly. Compressive, flexural, and tensile bond strength are different mechanical properties of all the mix that will be evaluated at 7 and 28 days. The effects of the replacements are to be analysed on the formation of structure, C-S-H gel, and composition with regard to the studies through morphology and microstructure tests conducted on the mortar specimens. The study shows positive results by doing up to 20% replacement with CT. After 3CT2, the results show a decrease in the results obtained from various durability tests. It will be carried out using codes, standard specimen casting, and testing methods. The results of this research will be very valuable in terms of the knowledge to be provided on copper tailing potential as a viable replacement in cement mortar and contribute much to developing far more environmentally friendly materials and construction processes.