Depending on the soil type their runs can be as deep as 2 feet and more.
None of the mole deterrents work and believe me we have tried them all.
The only solution is to kill them. Sorry.

I chased one away using empty drinks cans on canes, just stick a cane in every molehill and upend can on top
everytime a hill comes up push canes and cans in.....I eventually drove it in the ditch , must be 15 or 20 years ago now........

the garden looked very odd but it was a talking point for a while :0)

Dynamite!

Our cat caught all three of the ones in our garden.It was funny to see her crouched over a molehill obviously listening for the best time to stick a paw in...

Thanks to everyone regarding my cast iron fire pit and my potential mole problem.
I think I will use the fire pit as a water feature. If it works I will post a photo, probably next year.
Regarding the mole, the tin can on a stick is well worth a try. I'm grateful for the info on the electronic systems. It will save me money.
The dynamite could be the answer, but I wonder what the neighbours will think.
Many years ago back in about 1962, my uncle and aunt lived in deepest Kent without close neighbours. In their orchard they found a hornets nest in the roots of and under an ancient pear tree. Being resourceful and of a certain age , Peter, my uncle knew how to make explosives from fertiliser and various other household components. He made a batch stuffed it into a 2LB cocoa tin set a fuse and rammed it under the tree. He lit the fuse and we all stood well back at the other end of the orchard.
There was an almighty bang, the blast blew off my auntie's hat, a dusty mushroom cloud climbed above the orchard, and we were showered with leaves twigs and dead hornets.
We went back to the tree and it had been transformed into a mangrove tree at low tide. There was a complete canopy of roots holding the tree up.
That tree, in that state, lasted another several years, and was great fun for the kids and dogs to play under, making their own bare rooted tepee. [What Health and Safety]
Thanks to all and especially to Myron for dredging up a memory of a happier time.
SouthportSmith

What a wonderful story, it made me laugh and also brings back memories of a similar situation that happened about 20 years ago. A friend of mine chopped down a large tree to make room for a big workshop he wanted to build. He was left with the remnants of the trunk and the roots. He asked me what was the best way to get rid of it and a bit tongue in cheek I told him that if he went to the police station, told them what he wanted to do and give them all the details of where the tree trunk was, etc, then the police can issue a licence to buy explosives for him to do the job as I Had heard that this is possible but when he inquired at the local police station they said no way. I then said, why don't you make your own? I'd done some time with the bomb disposal in the army so I knew about these things and told him to go and buy a couple of 50 lb bags of ammonium nitrate. He went to a farmer friend of his, got the stuff and we mixed it with diesel to make ANFO. We dug around the tree as best we could, buried the explosive and set it off. The explosion was huge, debris was everywhere. It did the trick though and left a 5 foot crater. Unfortunately the police turned up to see what was going on, we both scarpered, but they put two and two together and turned up at his house. He never did dob me in though :o)