Upon inspection of the hole, the soil seems to have some type of white powdery substance mixed in with it, and the soil around the iside of the hole seems quite crumbly. A few days ago i was pulling weeds from a nearby (and overgrown) flower bed and notcied the roots had perhaps some type of white mold or fungus on nearly everything i pulled. I'm not really too concerned about the flower bed (or the weeds accompanying them), but what is this stuff? Will it hurt future plantings in this bed, and would have anything to do with the sinkhole?

I'll try to get a picture ASAP.

Where are you located? Is your area prone to sinkholes?

What kind of soil do you have?

Are you having unusual weather this summer - drought for example?

Are there storm drains or sewers near the area? Any unusual wet spots or runoff?

If the sinkhole is under your driveway, did part of the driveway cave in? Is your driveway concrete, asphalt, or gravel?

My first thought is that the base course or substrate under your concrete driveway is something like limestone quarry fines, which can look white, but that may be a stretch.

Dig down into the hole a bit. Is the soil damp or dry? Ram a piece of rebar into the bottom. Do you feel resistance, or does it feel like the hole will be getting deeper? If the soil is dry, your water table may be dropping. If so, you and your neighbors may experience more sinkholes. If the soil is damp but the soil a few feet away is dry at the same depth, I would suspect a break in the water line.

The white stuff may be beneficial mycorrhizae if it is intertwined with plant material, or mineral salts if it feels kind of grainy and is mostly on the surface.

Sue