 CANONSBURG, Pa.--BUSINESS WIRE-- ETRN--Equitrans Midstream Corporation NYSE: ETRN today announced that its wholly owned subsidiary, EQM Midstream Partners, LP the Partnership, has commenced tender offers each, an Offer and, collectively, the Offers to purchase up to 350 million in aggregate principal amount as such amount may be increased or eliminated by the Partnership pursuant to the terms of the Offers, the Aggregate Maximum Principal Amount of its outstanding notes listed in the table 