MarkWest Pioneer, L.L.C.

Original Volume No. 1

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

Original Sheet No. 45 Original Sheet No. 45

GENERAL TERMS AND CONDITIONS

(Continued)

3.6. Measurement of Gross Calorific Heating Value, Carbon Dioxide, Oxygen,

Nitrogen and Hydrogen Sulfide

Transporter’s Gas chromatograph installed at the Receipt Point shall be used

to measure the gross calorific heating value, carbon dioxide, oxygen and

nitrogen levels in the Gas stream. The standard for calculation of gross

calorific heating value, specific gravity and compressibility of Gas

mixtures from compositional analysis shall be Gas Processors Association

Standard No. 2172-84, as amended or supplemented from time to time. If

Shipper accepts delivery of any Gas that contains moisture in excess of the

limit for dry Gas designated by the specifications referenced in Section 2

of the GT&C, the gross calorific heating value will be adjusted to reflect

the actual water vapor content of the Gas accordingly for billing purposes.

3.7. Determination of Total Delivered MMBtu

The total number of MMBtus delivered shall be determined by multiplying the

delivered gross calorific heating value, as determined in Section 3.1, by

the total volume of Gas. If the total MMBtu results obtained by use of

Transporter’s equipment differ by one percent or more from the results

obtained by use of Shipper’s check metering equipment, then Transporter and

Shipper shall each be required to calibrate its measurement equipment. If

such calibrations indicate that Transporter’s measurement equipment is not

within the tolerance levels set forth in Section 3.3 and that Shipper’s

measurement equipment is within the tolerance levels set forth in Section

3.3, then Shipper’s measurement equipment shall be used. If such

calibrations indicate that neither parties’ measurement equipment is within

the tolerance levels set forth in Section 3.3, then the provisions of

Section 3.4 shall be followed to resolve any measurement inaccuracies.