MarkWest Energy Partners, L.P. (NYSE: MWE) and MarkWest Liberty Ethane Pipeline, L.L.C. (“MarkWest Liberty”), collectively “MarkWest,” will hold a binding open season for the previously announced Liberty Ethane Pipeline. The open season will commence at 8:00 a.m. Mountain Time on November 8, 2013 and will end at 5:00 p.m. Mountain Time on December 9, 2013. This pipeline is part of MarkWest’s comprehensive ethane solution in the Northeast, which will include purity ethane transportation infrastructure and de-ethanization facilities located in Pennsylvania, West Virginia, and Ohio. Subject to the outcome of the binding open season and all of the necessary regulatory authorizations, the Liberty Ethane Pipeline will transport purity ethane from Majorsville, Pennsylvania, to Houston, Pennsylvania. From there, shippers will have direct access to multiple, major ethane takeaway projects including Mariner West, Mariner East, and ATEX. The Liberty Ethane Pipeline is expected to become operational in the fourth quarter of 2013. The binding open season will allow interested parties to make volume commitments and execute long-term transportation contracts with MarkWest Liberty for transportation on the Liberty Ethane Pipeline. Shippers electing to make long-term volume commitments to MarkWest Liberty will be eligible to receive priority transportation service at a premium transportation rate for their committed volumes. The Liberty Ethane Pipeline will provide transportation of purity ethane to ethane markets in North America and internationally. MarkWest is the first midstream operator in the Northeast to offer its producer customers the ability to recover and produce purity ethane and provide access to all announced large-scale ethane pipeline projects. Ethane produced in the Northeast has the potential to become a key driver for the future expansion of the global petrochemical industry. Parties interested in participating in the open season and shipping on the Liberty Ethane Pipeline should contact Joshua Hallenbeck, VP of Finance and Treasurer at (866) 858-0482 or firstname.lastname@example.org. Information on the Liberty Ethane Pipeline and the binding open season can also be found on MarkWest’s website at: http://www.markwest.com/operations/ferc-pipelines/liberty-ethane-pipeline. MarkWest Energy Partners, L.P. is a master limited partnership engaged in the gathering, processing and transportation of natural gas; the gathering, transportation, fractionation, storage and marketing of natural gas liquids; and the gathering and transportation of crude oil. MarkWest has a leading presence in many unconventional gas plays including the Marcellus Shale, Utica Shale, Huron/Berea Shale, Haynesville Shale, Woodford Shale and Granite Wash formation.