I had gophers, really bad, in my back yard. In fact, they totally ruined it.
I learned, though, that gophers just love Juicy Fruit brand gum. They can't resist it. Trouble is, it gums up (pun intended) their digestive tract, so that they can't eat anything and have it pass through. They literally starve to death with a full belly.
I can testify to this fact, as I have used Juicy Fruit gum to eliminate gophers in my yard.
Such a thing may work for moles as well.
How to do it (if you feel inclined to accept my advice):
1) Find the mole hill (reasonably easy to do);
2) Using a steel rod (about 1/4 to 3/8 inch diameter and about 4 feet long or so), push into the mole hill, gently, at different angles; the purpose of this is to find the direction of the surface tunnel to the main tunnel, where the mole actually move around and lives and moves around; when you feel the rod pressing through without much resistance, you've found the surface tunnel; when the rod suddenly moves into the ground as you press it through, then suddenly stops, you have found the main tunnel;
3) Dig down to the main tunnel, using the angle of the rod as a guide;
4) When you reach the main tunnel, place some sticks of Juicy Fruit gum in the main tunnel, on either side of the hole; the mole (or gopher, as I suspect you may have) will come toward the light source, intending to close it up again, and come upon the gum, eat it, and then close up the hole again.
5) You may have to do this several times, at different holes, but it should be done with in about two weeks.
Hope this helps!