To thin in metal, not heavy cast iron, with three-four holes to put the pick axe into & there is no way you can pick up a true manhole cover from the sides UNLESS the ones in the States are different. Besides true man-hole covers are made to stand the weight of the most heavy of vehicles. One uses the pick axe to free it from road, to let it drop & pick-axe in again to DRAG it away from the hole or drag it back in again. I spent 3 or 4 years dealing with man-hole & other covers.
The side-walk covers are about 1/3 thickness, of sheet steel, or even ligher with some that have one or two grab bars that can be brought up so a simple one man operation with no sweat of WCCB bitching that the worker is picking up to much weight.