MarkWest Pioneer, L.L.C.

Original Volume No. 1

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

Original Sheet No. 44 Original Sheet No. 44

GENERAL TERMS AND CONDITIONS

(Continued)

3.4. (continued)

performed. During any period when any item of equipment installed at the

Delivery Point(s) by Transporter is inoperable or known to be in error, the

measurements provided by the corresponding item of equipment installed by

Shipper, if any, shall be used if determined to be accurate. If neither

item of equipment is operable or accurate, or available in the case of

Shipper’s equipment, the specification to be measured shall be determined by

the parties hereto on the basis of the best data available using the first

of the following methods which is feasible:

3.4.1. By correcting the error if the percentage of error is ascertainable

by calibration, test, or mathematical calculations; or

3.4.2. By comparing deliveries made during the preceding period under

similar delivery conditions when the equipment was registering

accurately.

3.5. Measurement of Moisture

Transporter may install on-line at the Delivery Point(s) the most accurate

and reliable technology currently available at reasonable cost to

continuously monitor the moisture content of the Gas being delivered by

Transporter. Moisture content monitoring equipment installed by

Transporter, if any, will have the capacity for an alarm, which may be

installed by Shipper, to inform Shipper whenever the moisture content of the

Gas being delivered to Shipper exceeds the maximum designated by the Tariff

specifications referenced in Section 2 of the GT&C. If Transporter does not

install moisture monitoring equipment as permitted by this section,

Shipper’s moisture monitoring equipment located on-line at the Delivery

Point(s) will be used to determine the moisture content of Gas being

delivered by Transporter, if that equipment has been properly installed and

maintained and is registering correctly. Shipper will promptly notify

Transporter if the moisture content of Gas being delivered to Shipper

exceeds the maximum designated by the specifications referenced in Section 2

of the GT&C.