This AP article says the United Mine Workers of America has reorganized its organization, including the elimination of districts as separate entities from the international union.
The ability of the districts to conspire with the international was a bone of contention in a case we litigated long ago, called Ramar v. UMWA, 814 F. Supp. 502 (W.D. Va. 1993), In that opinion, on the defendants' post-trial motions, Judge Wilson ruled that they had waived the issue of whether it was legally impossible for the different unions to conspire, for purposes of a claim under the Virginia Business Conspiracy statutes, Va. Code 18.2-499 and 18.2-500.
(I call them the Virginia Business Conspiracy statutes - there is however an interesting law review article by Professor Ulrich of Washington & Lee explaining that this statute was passed during the age of the civil rights movement to create a civil (and criminal) remedy for sit-ins seeking the integration of lunch counters and the like.)