There is a huge hole, about the size of one cinder block, that the heating oil tank piping goes through in my basement (see attached pictures). It follows under my front porch concrete slab and "elbows" up to the surface, to the oil fill outlets. Obviously, this needs to be closed up (from the inside basement side) to prevent "critters" from entering into my basement. However, I'm not sure what is the best approach. I'm guessing expanding foam wouldn't work, since the hole is too large. I could patch it with some partial bricks or cinder blocks, but I'm not sure if this would interfere with any future work that may be done on the pipes. The pipes go through dirt and have a pretty good open area around it, so I'm wondering if I need to throw some gravel around it. I'd appreciate any advice that anyone in the know can give me. Thanks.