The other story alluded to in that article is probably Wheal Ayr related.
There were 2 sets of mining related problems around there.
There were 2 houses, semi-detached, central shared wall (clearly). Once place went up for sale, mining search said "drill it". Drillers rolled up and broke into workings. I recall them trying to underpin it but having problems with multiple voids. The original firm doing the work gave up, from what I gathered.
The house went to auction and got £5k. Someone connected with the job commented that "you couldn't pay me to have it". The property description read "prospective clients are advised to read the legal pack". I gather the next door neighbour (who had lived there since St Ives was a mining/fishing town) said "There are no workings under my property". The whole challenge was remediating that half of the plot without causing any movement concerning the old boy's half. Obviously, there were massive liability/insurance issues with this.
"They just built over anything" is probably an apt description.
There is a mine which used to have lots of ivy on it's engine house and now doesn't. Some people have put their home brew bungalow over a major shaft nearby.
You only run into mining issues when you are dealing with a money lender!
Banks don't take risks (anymore).