The navy has cut the number of days it's minesweepers are at sea for training from 104 days a year to 72. The reduction wasn't because the navy wasn't keen on maintaining it's minesweeping skills, but because the diesel engines on the Avenger class minehunter ships are not very reliable. In the past, this has made it difficult for miniehunters to get out to sea 104 days a year. So the number of sea days is being reduced and more emphasis is being placed on pier side and electronic (simulation) training.
The navy also has a dozen smaller Osprey class coastal mine hunters (900 tons displacement, crew of 51), in addition to the 14 older seagoing Avenger class (1,300 tons displacement, crew of 83.) The 56 new LCS (Littoral Combat Ships) class vessels will have mine hunting modules that can be quickly installed to turn any LCS into a mine hunter equal in capability to the current mine hunter ships.
One (largely unspoken) reason the navy wants to use the LCS ships for mine hunting is to get mine hunting ships and equipment out of Texas. The Texas Congressional delegation thought they had scored a coup when they forced the navy to base its mine hunting ships at Ingleside, Texas. But this was the last place the navy wanted it's mine hunting ships. That's because the most likely places mine hunters would be needed in wartime are at the major ports on the east and west coasts, not in the Gulf of Mexico. But the Texas Congressional delegation has made keeping the minesweepers, (and all the local jobs and business for Texas firms) right where it is, a major issue. Not even a president from Texas has been willing to go up against that. The LCS ships are not, strictly speaking, mine hunters. The LCS has a large "cargo bay" designed to accept freight container like modules designed to plug right into the ships electrical and communications systems and add different types of capabilities (gun fire, mine hunting, anti-aircraft). So the LCS ships won't have to be based at the Texas port. The legislators from Texas may dispute that point, but the navy is confident they can start phasing the older Avenger mine hunters out of service and shrinking the Ingleside, Texas, base.