MarkWest Pioneer, L.L.C.

Original Volume No. 1

 Contents / Previous / Next / Main Tariff Index

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

Original Sheet No. 52 Original Sheet No. 52

GENERAL TERMS AND CONDITIONS

(Continued)

6.10.2. Reservation of Capacity for Expansion Projects – Transporter may

reserve for a future expansion project any currently available

unsubscribed capacity or capacity to become available at some future

date, provided such capacity is not subject to a Right of First

Refusal (“ROFR”). Transporter may reserve capacity only for a

future expansion project for which an open season has been held or

will be held within one (1) year of the date Transporter posts such

capacity as being reserved. Capacity may be reserved for up to one

(1) year prior to Transporter filing for certificate approval for

the expansion project, and thereafter until such expansion is placed

into service. Transporter shall, on a limited-term basis up to the

in-service date of the expansion project, make generally available

any capacity reserved under this section.

7. CREDITWORTHINESS

7.1. General – Transporter shall not be required to (a) execute a FT or IT

Agreement providing for service under the applicable Rate Schedule for any

Shipper who fails to meet Transporter’s standards for creditworthiness, or

(b) initiate service for a Shipper who fails to meet Transporter’s standards

for creditworthiness, or (c) continue service for any Shipper who is or has

become non-creditworthy or who, at Transporter’s request, fails within a

reasonable period to demonstrate creditworthiness pursuant to Transporter’s

standards. If Shipper is found to be non-creditworthy, Transporter will,

upon request, inform Shipper in writing as to the reasons Shipper has been

deemed non-creditworthy.

7.2. Credit Appraisal Information – Transporter shall perform a credit appraisal,

if applicable, by utilizing any or all of the following information which

Shipper shall furnish to Transporter:

7.2.1. A copy of Shipper’s most recent audited financial statements;

7.2.2. A copy of Shipper’s most recent twelve (12) month audited financial

statement or Annual Report and, if applicable, SEC 10-K form;