The design of a ventilation systems in deep underground coal mines is a critical endeavor to ensure the workplace safety and productivity of miners operating in extremely challenging conditions. This paper presents a comprehensive exploration of the different strategies involved in revamping the ventilation systems for two interconnected deep underground coal mines with multi-seam workings having liabilities of upper seam sealed-off fire areas and goaved out seams. Both the deep underground coal mines of Jharia coalfield, India are connected to each other having a common ventilation scheme. The efficient ventilation system design process involves a thorough ventilation survey of both the mines, an analysis of the mine layout, geological and technological factors, etc. Presently both the mines are in operation having overall fan efficiency of 42.8%. Accordingly, the redesign of the ventilation system has been carried out through computer simulation of the combined ventilation networks to operate a single fan to reduce energy cost. The result of the computer simulation reveals that one mechanical ventilator will provide the required air quantity to operate both the mines. The above study helps to save 45.19% of air power cost in ventilation for both the mines.