MarkWest Liberty Midstream & Resources – a majority-owned joint venture of MarkWest Energy Partners L.P. (MWE) – yesterday announced the signing of definitive agreements with subsidiaries of Chesapeake Energy Corp. (CHK) and Statoil Hydro ASA (STO) to process gas at its proposed facility in Majorsville, West Virginia.   MarkWest Liberty is a partnership between natural gas pipeline operator MarkWest Energy Partners and energy infrastructure private equity fund NGP Midstream & Resources L.P. MarkWest has a 60% operated interest in the venture (remaining 40% owned by NGP) that has been formed to construct and operate natural gas midstream services to support producers in the emerging Marcellus Shale play in western Pennsylvania and West Virginia.   The new processing deals are in addition to a previously announced agreement with independent oil and gas company Range Resources Corp. (RRC) that was executed earlier this year. All three contracts include