Light Grey Conglomerate

You would think that this is a poor concrete core.
No, it was extracted 11m depth below the ground, not far from the junction of Pan Borneo trunk road to Simunjan.

It is not a common sedimentary rock, characterised by cemented gravels and cobbles. The gravels appear to be only slightly rounded, indicating that it did not roll down the stream long enough before it got buried and cemented.

If the fragments are finer, angular and irregular, then the rock is called Breccia.