Stonehenge Energy Resources Sells Midstream Assets to MarkWest Energy Partners for $512 Million & Announces Formation of Stonehenge Energy Resources II

DENVER–(BUSINESS WIRE)–Stonehenge Energy Resources, L.P. (“Stonehenge”) announced today that it, together with its partners in Keystone Midstream Services, LLC (“Keystone”), closed on a transaction with a subsidiary of MarkWest Energy Partners, L.P. (NYSE: MWE) whereby MarkWest has acquired Keystone for a purchase price of $512 million, subject to adjustment for working capital. Stonehenge ( held a 60% interest in Keystone, with the remaining 40% owned by affiliates of Rex Energy Corporation (NASDAQ: REXX) and Sumitomo Corporation. Evercore Partners acted as exclusive financial adviser to Keystone on the transaction.

The Keystone system includes the Sarsen and Bluestone cryogenic gas processing plants with a combined 90 MMcf/d of capacity, a gas gathering system and associated field compression located in Butler County, Pennsylvania. The Bluestone plant has a nominal capacity of 50 MMcf/d and is in the final stage of commissioning.

Stonehenge, headquartered in Westminster, Colorado, is backed by Energy Spectrum Capital ( and supported by Kahuna Ventures LLC ( Energy Spectrum is a leading private equity firm located in Dallas, Texas. Kahuna is a midstream-focused engineering consulting company located in Westminster, Colorado.

Stonehenge Energy Resources II, L.P. (“Stonehenge II”) was recently formed to pursue natural gas midstream opportunities, focusing on the U.S. Appalachia and Rocky Mountain regions. Additionally, Stonehenge Ohio Partners, LLC (“Stonehenge Ohio”) has been formed to develop midstream projects in eastern Ohio. Stonehenge Ohio is owed by Stonehenge II and Hawk Midstream, LLC, an Ohio-based midstream company.