MarkWest Pioneer, L.L.C.

Original Volume No. 1

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

Original Sheet No. 34 Original Sheet No. 34

GENERAL TERMS AND CONDITIONS

1. DEFINITIONS

Except where the context expressly states another meaning, the following terms when

used in this Tariff and in any Transportation Agreement or Rate Schedule

incorporating this Tariff, shall be construed to have the following meanings:

1.1. “Authorized Overrun” is a nomination accepted by Transporter that exceeds

Shipper’s Maximum Daily Quantity.

1.2. “Authorized Overrun Service” (or “AOS”) means service provided by

Transporter for Shipper’s Authorized Overrun quantities. Authorized Overrun

Service is subject to available capacity, and subject to an Authorized

Overrun Charge shown on the Statement of Rates and Charges.

1.3. “Available Capacity” is the capacity in Transporter’s system that is not

subscribed or scheduled for service under the terms of Transporter’s Rate

Schedules.

1.4. “Btu” shall mean one (1) British Thermal Unit. The reporting basis for Btu

shall be 14.73 dry psia and 60 degrees F.

1.5. “Business Day” is Monday through Friday, excluding Federal Banking Holidays

for transactions in the U.S., and similar holidays for transactions

occurring in Canada and Mexico.

1.6. “Central Clock Time” or “CCT” means Central Daylight Time when Daylight

Savings Time is in effect and Central Standard Time otherwise.

1.7. “Commission” means the Federal Energy Regulatory Commission or any

successors thereto.

1.8. “Commodity Charge” means the commodity charge component of the rate

applicable to service under Rate Schedules FT-1 and IT, as specified in

Transporter’s Tariff and the FT-1 Agreement or IT Agreement between Shipper

and Transporter.