DENVER--(BUSINESS WIRE)--May. 29, 2012--
MarkWest Energy Partners. L.P. (NYSE:MWE) today announced the closing of
the previously announced acquisition of Keystone Midstream Services, LLC
(Keystone) from Stonehenge Energy Resources, L.P., and subsidiaries of
Rex Energy Corporation (Rex Energy) (NASDAQ:REXX) and Sumitomo
Corporation (Sumitomo).
The acquisition consideration was $512 million. Keystone’s existing
assets are located in Butler County, Pennsylvania and include two
cryogenic gas processing plants totaling 90 million cubic feet per day
of processing capacity, a gas gathering system and associated field
compression. Concurrent with the closing of the transaction, Rex Energy
and Sumitomo have dedicated an 895 square mile area to MarkWest.
MarkWest will gather and process rich gas, and fractionate the natural
gas liquids under long-term, fee-based agreements.
MarkWest’s acquisition of Keystone expands the Partnership’s leading
position in the liquids rich Marcellus Shale area into northwest
Pennsylvania and eastern Ohio.
MarkWest Energy Partners, L.P. is a master limited partnership
engaged in the gathering, transportation, and processing of natural gas;
the transportation, fractionation, marketing, and storage of natural gas
liquids; and the gathering and transportation of crude oil. MarkWest has
extensive natural gas gathering, processing, and transmission operations
in the southwest, Gulf Coast, and northeast regions of the United
States, including the Marcellus Shale, and is the largest natural gas
processor and fractionator in the Appalachian region.
This press release includes “forward-looking statements.” All
statements other than statements of historical facts included or
incorporated herein may constitute forward-looking statements. Actual
results could vary significantly from those expressed or implied in such
statements and are subject to a number of risks and uncertainties.
Although MarkWest believes that the expectations reflected in the
forward-looking statements are reasonable, MarkWest can give no
assurance that such expectations will prove to be correct. The
forward-looking statements involve risks and uncertainties that affect
its operations, financial performance, and other factors as discussed in
MarkWest’s filings with the Securities and Exchange Commission. Among
the factors that could cause results to differ materially are those
risks discussed in the periodic reports filed with the SEC, including
MarkWest’s Annual Report on Form 10-K for the year ended December 31,
2011, and its Quarterly Report on Form 10-Q for the quarter ended March
31, 2012. You are urged to carefully review and consider the cautionary
statements and other disclosures made in those filings, specifically
those under the heading “Risk Factors.” MarkWest does not
undertake any duty to update any forward-looking statement except as
required by law.

Source: MarkWest Energy Partners
MarkWest Energy Partners, L.P.
Frank Semple, 866-858-0482
Chairman,
President & CEO
or
Nancy Buese, 866-858-0482
Senior
VP and CFO
or
Josh Hallenbeck, 866-858-0482
VP
of Finance & Treasurer
investorrelations@markwest.com