This paper discusses through a case study, some of the challenges in construction of a supplementary deep shaft (15 m long, 2.6 m wide and 23 m deep) located adjacent to an existing deep shaft (38 m long, 10 m wide and 24 m deep) and in close proximity of a bored tunnel in River Channel deposits of Kolkata. The shaft construction also included connections to both the existing shaft and to the tunnel. The support system for the fresh excavation consisted of a 1000 mm diameter secant pile wall comprising of hard and soft piles overlapping with each other. Six levels of strut/waler arrangement and base slab formed the lateral restraining system. Soil Investigation was earlier carried out in the area to assess the geotechnical properties of the native soils which were used to establish geotechnical parameters to be used in the analysis and design. Geotechnical profile for the excavation zone indicated predominance of silty fine sands and sandy silts. Groundwater table was present at 4 m below existing ground level. Analysis was performed using FEM viz. Plaxis-2D to study the impact on adjacent structures as well as for designing the braced excavation system. Instrumentation and Monitoring played a major role during the excavation process. Based on our analyses, AAA (Alert-Action-Alarm) values were set for allowable secant pile, existing tunnel movements and allowable deflections in the existing shaft. Additional mitigation measures including ground improvement and precautionary distortion controlling measures inside bored tunnel and existing shaft were administered to ensure safety of the whole system.