On Wed, 5 Mar 2008 20:30:06 -0000, "BRG" wrote:

blackbat,

It may well be screwed down to ensure an air-tight seal. Have a look in
those 'tiny holes' and you may find the screw heads (brass or non-ferrous) -
if they are there, simply unscrew them first and the cover will lift out.

I've cleared any debris out of the holes with compressed air. All I
can see is another threaded hole further inside. I guess there must be
some key etc that fits those threads to allow lifting.

Tips:

1 The 'concrete' is probably screed and will be no more than two inches
thick - so fairly light.
2 Before you start, nip down to the local builders merchants (Jewsons)
and buy yourself a couple of manhole lifting keys to suit for a couple of
pounds.

--

blackbat /\x/\