MarkWest Energy Partners, L.P. (NYSE: MWE) (“MarkWest and “the Partnership”) today announced an expansion of rich-gas processing capacity in the Marcellus Shale. The Partnership will continue developing its leading presence in America’s most productive natural gas resource play with the addition of two new cryogenic processing plants at its Sherwood complex in Doddridge County, West Virginia and its Mobley Complex in Wetzel County, West Virginia. At the Sherwood complex, MarkWest will construct an additional 200 million cubic feet per day (MMcf/d) processing plant at the request of Antero Resources Corporation (NYSE: AR) (Antero). The new plant is anchored by a long-term, fee-based contract and will expand total capacity at the Sherwood complex to 1.2 billion cubic feet (Bcf/d) by the second quarter of 2015. Antero continues to develop its prolific rich-gas acreage position in northern West Virginia and is the anchor producer supporting the Sherwood complex. At the Mobley complex, MarkWest will increase total processing capacity to 920 MMcf/d with the construction of an additional 200 million cubic feet per day processing plant at the request of EQT Corporation (NYSE: EQT). The new plant is anchored by a long-term, fee-based contract and is expected to be in service by the second quarter of 2015. The Mobley complex currently consists of three plants with 520 MMcf/d of total processing capacity and during the fourth quarter of this year, MarkWest will begin operations of a fourth plant at the complex, increasing capacity to 720 MMcf/d. The Mobley complex supports growing Marcellus rich-gas production from EQT, Magnum Hunter Resources Corporation (NYSE: MHR), Stone Energy Corporation (NYSE: SGY), CONSOL Energy Inc. (NYSE: CNX), and Noble Energy, Inc. (NYSE: NBL). MarkWest continues to develop its leading midstream position in the Marcellus and Utica shales with 17 major processing and fractionation projects currently under development. In 2014, MarkWest expects to complete 11 of these projects, bringing total Northeast processing and fractionation capacity to 4 Bcf/d and 250,000 barrels per day, respectively.