In a nutshell, there's a new mining frigate on the way, and current mining frigates will no longer be mining frigates. "The goal here is to allow players to choose a barge that fits their specific play style rather than lead them on a journey from the worst barge to the best one," CCP says.
Other changes include reduced skill requirements for both barges and exhumers. This "might not make [mining] any more exciting, but at least miners will have to make some meaningful decisions before they undock," according to the devs.
That's just the tip of the iceberg, of course, so head to the official EVE Online website for more.