Kind of a variation to the “blow ‘em up” technique is something someone told me just last year. They fill up a 5 gallon propane tank (like the ones you use on a barbecue) and empty it deep into one of the mole holes (with any other open holes plugged up). Apparently the properties of the propane will cause it to settle into the lowest point of its environment which is the nesting place of the mole. This will kill them deader than dead. He said he has a 100% success rate with this technique with NO NEED TO IGNITE. The gas does the job on its own.
NO NEED TO IGNITE.