NiSource Midstream Services and MarkWest Liberty Midstream & Resources Announce Commencement of Majorsville Processing Complex

HOUSTON and DENVER
PRNewswire via COMTEX News Network

September 27, 2010 - PRESS RELEASE
Source: NiSource Gas Transmission & Storage

NiSource Gas Transmission & Storage unit NiSource Midstream Services (NMS), and MarkWest Liberty Midstream & Resources, L.L.C., a partnership between MarkWest Energy Partners, L.P. and The Energy & Minerals Group, today announced the commencement of operations of jointly developed natural gas gathering, processing, and transmission projects in Majorsville, West Virginia.

The Majorsville complex is the first integrated gathering and processing system serving Marcellus production in northern West Virginia and significantly augments the midstream infrastructure that NMS and MarkWest Liberty independently operate in southwest Pennsylvania. The gathering and processing facilities are fully contracted and will serve various producers, including affiliates of Chesapeake Energy Corporation, Chief Oil & Gas, CONSOL Energy/CNX Gas, Range Resources, and Statoil.

On August 1, 2010, NMS completed a re-functionalization of pipeline and compression assets in West Virginia and Pennsylvania, including the re-commissioning of the Majorsville compressor station. The pipeline and compression assets allow NMS to gather and deliver 88,000 dekatherms per day (Dth/d) of liquid-rich Marcellus gas production from Washington and Greene Counties in Pennsylvania and 250,000 Dth/d from Marshall, Wetzel, and Doddridge Counties in West Virginia to the new MarkWest Liberty Majorsville processing plant. Residue gas from the processing plant is currently delivered into the NGT&S interstate pipeline system and, in October, construction will begin on a pipeline to deliver residue gas to the Texas Eastern Windridge compressor that will provide significant additional outlet capacity to eastern markets. A January 2011 in-service date is planned.

On September 7, 2010, MarkWest Liberty commenced operations of a 120 million cubic feet per day (MMcf/d) cryogenic natural gas processing plant at the Majorsville complex and a 35-mile natural gas liquids (NGL) pipeline that connects the Majorsville complex to MarkWest Liberty's midstream complex in Houston, Pennsylvania, where NGLs are fractionated, transported, stored, and marketed into high-value markets in the northeastern United States.

In 2011, MarkWest Liberty plans to expand its cryogenic processing capacity at the Majorsville complex to 270 MMcf/d. Concurrently, the Houston cryogenic processing capacity will be expanded from 155 MMcf/d to 355 MMcf/d. To accommodate the significant increase in NGL production resulting from the processing expansions, MarkWest Liberty is constructing fractionation capacity of 60,000 barrels per day, which will allow for the production of commercial iso-butane, normal butane, and natural gasoline in addition to the current capabilities of producing purity propane. When combined with an existing 24,000 barrel per day fractionation, storage, and marketing facility near Portsmouth, Ohio, MarkWest's combined NGL infrastructure in the Marcellus and Appalachian basin will include nearly 85,000 barrels per day of fractionation, storage, and marketing capacity.

"With the commencement of the Majorsville processing complex, producers in the Marcellus Shale region will now have access to the additional capacity they have long needed to move their gas to downstream markets," said Christopher A. Helms, executive vice president and group CEO for NGT&S. "A significant initiative for NGT&S is to offer new solutions to customers for transportation of supplies to valuable markets, and our joint project with MarkWest Liberty is a great example of this. We will continue our strategy of disciplined investment in growth projects to adapt our system to provide critical services to our customers."

"We are pleased to jointly announce with NiSource Midstream Services the commencement of the Majorsville gathering, processing, and transmission complex," commented Frank Semple, Chairman, President and Chief Executive Officer of MarkWest. "MarkWest Liberty is the largest provider of midstream services in the Marcellus and we continue to invest a significant amount of capital to provide the critical midstream infrastructure necessary to economically develop this world-class resource. The Majorsville expansion further demonstrates MarkWest Liberty's commitment to develop the facilities required to meet our producer customers' long-term needs."

For more information about NiSource Gas Transmission & Storage, please visit www.ngts.com.

As units of NiSource, Inc., the NGT&S companies include Columbia Gas Transmission, Columbia Gulf Transmission, Crossroads Pipeline, Hardy Storage, Millennium Pipeline and NiSource Midstream Services. Combined, the companies operate about 15,000 miles of interstate natural gas pipeline and 37 storage fields, delivering over 1 trillion cubic feet of natural gas per year.

About NiSource

NiSource Inc. (NYSE: NI), based in Merrillville, Ind., is a Fortune 500 company engaged in natural gas transmission, storage and distribution, as well as electric generation, transmission and distribution. NiSource operating companies deliver energy to more than 3.8 million customers located within the high-demand energy corridor stretching from the Gulf Coast through the Midwest to New England. Information about NiSource and its subsidiaries is available via the Internet at www.nisource.com. NI-F

About MarkWest Energy Partners

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 in the Appalachian region.

About The Energy & Minerals Group

The Energy & Minerals Group is the management company for a series of private equity funds totaling in excess of $2 billion of commitments. EMG focuses exclusively on making direct investments across the natural resources industry in conjunction with experienced management teams focused on hard assets that are integral to existing and growing markets.

NiSource Forward-Looking Statements

This news release includes forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. Those statements include statements regarding the intent, belief or current expectations of NiSource and its management. Although NiSource believes that its expectations are based on reasonable assumptions, it can give no assurance that its goals will be achieved. Readers are cautioned that the forward-looking statements in this news release are not guarantees of future performance and involve a number of risks and uncertainties, and that actual results could differ materially from those indicated by such forward-looking statements. Important factors that could cause actual results to differ materially from those indicated by such forward-looking statements include, but are not limited to, the following: weather; fluctuations in supply and demand for energy commodities; growth opportunities for NiSource's businesses; increased competition in deregulated energy markets; the success of regulatory and commercial initiatives; dealings with third parties over whom NiSource has no control; actual operating experience of NiSource's assets; the regulatory process; regulatory and legislative changes; the impact of potential new environmental laws or regulations; the results of material litigation; changes in pension funding requirements; changes in general economic, capital and commodity market conditions; and counter-party credit risk, and the matters set forth in the "Risk Factors" section in NiSource's 2009 Annual Report on Form 10-K and subsequent Quarterly Reports on Forms 10-Q, many of which risks are beyond the control of NiSource. NiSource expressly disclaims a duty to update any of the forward-looking statements contained in this release.

MarkWest Energy Partners Forward-Looking Statements

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 operations, financial performance, and other factors as discussed in filings with the Securities and Exchange Commission. Among the factors that could cause results to differ materially are those risks discussed in periodic reports filed with the SEC, including MarkWest's Annual Report on Form 10-K for the year ended December 31, 2009, and Quarterly Report on Form 10-Q for the quarter ended June 30, 2010. 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.