MarkWest Pioneer, L.L.C.

Original Volume No. 1

Effective Date: 04/01/2009, Docket: RP09-321-000, Status: Effective

Original Sheet No. 100 Original Sheet No. 100

GENERAL TERMS AND CONDITIONS

(Continued)

27. IMPAIRMENT OF DELIVERIES/FORCE MAJEURE

27.1. Routine Repair and Maintenance. Transporter shall have the right to

restrict the scheduling of service in whole or in part on all or a portion

of its system from time to time to perform routine repair, maintenance, and

other construction or testing procedures on Transporter’s System or to

comply with applicable regulatory requirements. Transporter’s repair and

maintenance plans should not disrupt the delivery of confirmed services.

Transporter shall exercise due diligence to schedule such activity so as to

minimize disruptions of service to Shippers. Transporter shall have no

liability to Shipper or any other party for such curtailment of interruption

of service. Transporter will post notice of such events on its Internet

website.

27.2. Non-Force Majeure Service Interruption. If, due to an event other than

described below in Section 27.4, Transporter is unable to deliver on any day

under an FT-1 Agreement at least 98% of the Shipper’s MDQ then the

applicable Reservation Charges and related reservation-based surcharges

shall be eliminated for the quantity of gas not delivered. This reduction

in Reservation Charges shall not apply if the Shipper uses alternate points

under the FT-1 Agreement. Transporter shall not be obligated to adjust the

Shipper’s Reservation Charges when Transporter’s failure to deliver on any

day is the result of the conduct of the Shipper or the operator of the

downstream facilities at the delivery point. Notwithstanding this reduction

in Reservation Charges, Transporter shall have no other liability to any

Shipper or any other party for the scheduling of service to accommodate the

routine repair and maintenance of its system.

27.3. Force Majeure. Service under this Tariff may be interrupted or curtailed

for reasons of Force Majeure as defined in Section 27.4, and Transporter

shall give Shipper notice as soon as reasonably possible of such

interruptible or curtailment.