Subsequent Events

6 Months Ended

Jun. 30, 2013

Subsequent Events

Subsequent Events

18. Subsequent Events

Approximately four million Class B units converted to common units on July 1, 2013.  These converted units will participate in the distributions declared on July 24, 2013.  All of the Partnership’s Class B units were issued to and are held by M&R MWE Liberty, LLC, an affiliate of The Energy and Minerals Group (“EMG”), as part of the Company’s December 31, 2011 acquisition of the non-controlling interest in MarkWest Liberty Midstream & Resources, L.L.C. (“MarkWest Liberty Midstream”). The remaining Class B units will convert to common units on a one-for-one basis in four equal installments beginning on July 1, 2014 and each of the next three anniversaries of such date.