Marathon Petroleum Corp.'s midstream limited partnership, MPLX LP, and MarkWest Energy Partners LP have cleared initial federal approval for their $15.8 billion merger (see Shale Daily, July 13). The Federal Trade Commission and the Department of Justice sent notice of an early termination of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act. With early termination, the companies said the merger remains on track to close in the fourth quarter. It still requires the approval of MarkWest unitholders. The deal would pair MarkWest, the nation's second-largest natural gas processor and the Appalachian Basin's largest, with one of the Northeast's leading refiners.