Cornerstone Pipeline Begins Operations, Provides Connectivity to Utica Shale

FINDLAY, Ohio, Oct. 11, 2016 - MPLX LP MPLX today announced that its newly constructed Cornerstone Pipeline is now fully operational.

"Cornerstone is a state-of-the-art pipeline that adds superior safety, reliability and economics to existing transportation alternatives," said MPLX Chairman and CEO Gary R. Heminger. "As the first Utica shale liquids pipeline, Cornerstone is the initial step in MPLX's plan to provide better connectivity to the basin, which creates another condensate and natural gas liquids (NGL) transportation and marketing option for Marcellus and Utica producers and benefits end users."

The new 50-mile pipeline is designed to transport condensate and natural gasoline in a batched system from origination facilities in Harrison County, Ohio, to a tank farm in East Sparta, Ohio, where it can then continue on to Marathon Petroleum Corporation's MPC 93,000-barrels-per-day refinery in Canton, Ohio. MPLX is currently constructing and expanding additional pipelines, to provide further distribution to the Midwest and Canada, which are expected to be complete in 2017.

"Cornerstone is the backbone of our Utica shale strategy," Heminger added. "It is routed to provide optimal connectivity from condensate stabilizers and fractionators and aggregate Utica and Marcellus shale production for further distribution."

Cornerstone Pipeline is comprised of a 42-mile, 16-inch pipeline from Cadiz to East Sparta with 180,000 barrels per day of capacity and an 8-mile, 8-inch pipeline from East Sparta to Canton with 45,000 barrels per day of capacity. Marathon Pipe Line LLC, a subsidiary of MPLX, will operate Cornerstone Pipeline from its operations center in Findlay, Ohio, and with local operational personnel.

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About MPLX LP
MPLX is a diversified, growth-oriented master limited partnership formed in 2012 by Marathon Petroleum Corporation to own, operate, develop and acquire midstream energy infrastructure assets. We are engaged in the gathering, processing and transportation of natural gas; the gathering, transportation, fractionation, storage and marketing of NGLs; and the transportation and storage of crude oil and refined petroleum products. Headquartered in Findlay, Ohio, MPLX's assets consist of a network of common carrier crude oil and products pipeline assets located in the Midwest and Gulf Coast regions of the United States, an inland marine business, a butane storage cavern located in West Virginia with approximately one million barrels of storage capacity, crude oil and product storage facilities (tank farms) with approximately 4.5 million barrels of available storage capacity, a barge dock facility with approximately 78,000 barrels per day of crude oil and product throughput capacity and gathering and processing assets that include more than 5,000 miles of gas gathering and NGL pipelines, 54 gas processing plants, 13 NGL fractionation facilities and two condensate stabilization facilities.

Investor Relations Contacts:
Lisa D. Wilson (419) 421-2071
Teresa Homan (419) 421-2965

Media Contacts:
Chuck Rice (419) 421-2521
Sid Barth (419) 421-2850

Forward-looking Statements
This press release contains forward-looking statements within the meaning of federal securities laws regarding MPLX LP ("MPLX") and Marathon Petroleum Corporation ("MPC"). These forward-looking statements relate to, among other things, expectations, estimates and projections concerning the business and operations of MPLX and MPC. You can identify forward-looking statements by words such as "anticipate," "believe," "design," "estimate," "expect," "forecast," "goal," "guidance," "imply," "intend," "objective," "opportunity," "outlook," "plan," "position," "pursue," "prospective," "predict," "project," "potential," "seek," "strategy," "target," "could," "may," "should," "would," "will" or other similar expressions that convey the uncertainty of future events or outcomes. Such forward-looking statements are not guarantees of future performance and are subject to risks, uncertainties and other factors, some of which are beyond the companies' control and are difficult to predict. Factors that could cause MPLX's actual results to differ materially from those implied in the forward-looking statements include: negative capital market conditions, including a persistence or increase of the current yield on common units, which is higher than historical yields, adversely affecting MPLX's ability to meet its distribution growth guidance; risk that the synergies from the acquisition of MarkWest Energy Partners, L.P. ("MarkWest") by MPLX may not be fully realized or may take longer to realize than expected; disruption from the MPLX/MarkWest merger making it more difficult to maintain relationships with customers, employees or suppliers;  the adequacy of MPLX's capital resources and liquidity, including, but not limited to, availability of sufficient cash flow to pay distributions, and the ability to successfully execute its business plans and growth strategy; the timing and extent of changes in commodity prices and demand for crude oil, refined products, feedstocks or other hydrocarbon-based products; continued/further volatility in and/or degradation of market and industry conditions; changes to the expected construction costs and timing of projects; completion of midstream infrastructure by competitors; disruptions due to equipment interruption or failure, including electrical shortages and power grid failures; the suspension, reduction or termination of MPC's obligations under MPLX's commercial agreements; modifications to earnings and distribution growth objectives; the level of support from MPC, including drop-downs, alternative financing arrangements, taking equity units, and other methods of sponsor support, as a result of the capital allocation needs of the enterprise as a whole and its ability to provide support on commercially reasonable terms; compliance with federal and state environmental, economic, health and safety, energy and other policies and regulations and/or enforcement actions initiated thereunder; changes to MPLX's capital budget; other risk factors inherent to MPLX's industry; and the factors set forth under the heading "Risk Factors" in MPLX's Annual Report on Form 10-K for the year ended Dec. 31, 2015 and Quarterly Report on Form 10-Q for the quarter ended March 31, 2016, filed with the Securities and Exchange Commission (SEC). Factors that could cause MPC's actual results to differ materially from those implied in the forward-looking statements are set forth under the heading "Risk Factors" in MPC's Annual Report on Form 10-K for the year ended Dec. 31, 2015, filed with the SEC. In addition, the forward-looking statements included herein could be affected by general domestic and international economic and political conditions. Unpredictable or unknown factors not discussed here, in MPLX's Form 10-K and Form 10-Q, or in MPC's Form 10-K could also have material adverse effects on forward-looking statements. Copies of MPLX's Form 10-K and Form 10-Q are available on the SEC website, MPLX's website at http://ir.mplx.com or by contacting MPLX's Investor Relations office. Copies of MPC's Form 10-K are available on the SEC website, MPC's website at http://ir.marathonpetroleum.com or by contacting MPC's Investor Relations office.