Bengaluru to Kolkata OFC Corridor Contractor

The eastern diagonal is the longest of the routes we work and the one where survey contributes most, because a larger share of it crosses ground nobody holds a reliable record of. Mining country brings subsidence and abandoned workings; heavy industrial estates carry live and disused servicing side by side; and the river crossings are the widest on any Indian trunk alignment.

Why void detection belongs in the scope here

On most corridors the survey question is where services run. Through the Jharkhand and Odisha sections it is frequently whether the ground beneath the route is intact at all. Old workings, sometimes a century old and rarely mapped, produce subsidence risk that no utility survey grid would detect, because a cavity smaller than the line spacing is stepped over entirely. We run void detection at a density set for cavities and issue those findings as their own schedule, since merging them into a utility plan buries the more urgent of the two.

What is delivered on this corridor

A utility crossing schedule by chainage per section. A separate void and subsidence schedule where the route crosses worked ground, with grid density stated because a void survey's value depends entirely on it. River crossing designs against bank geology and scour depth. Six separate state permission workstreams. Estate permits held with the file where plant land is crossed, with live and disused servicing distinguished as far as the evidence allows and everything unconfirmed reported as potentially live. As-built profiles tied to coordinates, OTDR per fibre and restoration closed in each state.

Beyond the basics

Can radar find old mine workings? It finds cavities within its depth range at the grid density used, which is why we state the density. Deep workings need geotechnical investigation rather than radar.

Why treat disused industrial cable as live? Because on estates re-let repeatedly nobody can reliably say what was decommissioned, and a feed disconnected at one substation can be live from another direction.

How wide are the river crossings here? The widest on any Indian trunk route, which makes profile design against bank geology and scour considerably more consequential than span alone.

Is the Kolkata approach worth surveying separately? Yes. Deltaic ground limits achievable depth to among the lowest we report, and quoting it at plateau confidence would be misleading.

Would you decline a section of this route? Where a client requires a fixed-price bore across suspected worked ground without allowing survey, yes. That transfers a risk nobody has measured.

Terms used on this page

Worked ground — land previously mined, where subsidence and cavities are a structural risk. Void detection — surveying for cavities rather than services, at a grid set by the smallest cavity that matters. Deltaic ground — soft saturated silt and clay near a river delta, limiting radar depth. Potentially live — a service treated as energised until an owner confirms otherwise. Grid density — how closely survey lines are spaced, which determines what size of void can be found.