rumble on

To continue at a low but consistent level or degree, especially when no clear conclusion or resolution seems imminent or likely. Said especially of some argument, complaint, debate, discussion, etc. The issue has been rumbling on in the background of our industry for nearly 10 years now, but we're still no closer to figuring out a solution to it. Recently, a dispute between environmentalists and archaeologists has rumbled on regarding the latter's intent to excavate an ancient burial site for the sake of studying the hieroglyphs scrawled on the stone slabs inside.