Is the concrete well covered or made of pig iron?
If the manhole cover on the road, oh, feel good cast iron, maintenance costs are low, you can say that after the basic repair will not be good, the concrete is easy to bad, often replaced, and later maintenance costs are too high;
As for the cast iron that everybody says is easy to throw, it is really a problem, but now the well rings and manhole covers are all connected together. It is not the cast iron manhole cover of the past few years.
Pig iron, high strength, generally will not be crushed, crushed, can often be stolen. Concrete has no iron resistance, but it costs less and maintains simpler points. The thief won't be able to steal a big piece of cement.
