Questar Southern Trails Pipeline Company

Original Volume No. 1

Effective Date: 01/23/2006, Docket: RP06-154-000, Status: Effective

First Revised Sheet No. 85 First Revised Sheet No. 85 : Effective

Superseding: Original Sheet No. 85

GENERAL TERMS AND CONDITIONS

adjustments in order to maintain a thermal balance of receipts and deliveries.

(b) Southern Trails shall monitor, to the extent of its ability,

receipts and deliveries of gas as compared to quantities nominated by Shipper,

and, based upon available information, advise Shipper of any imbalances. Upon

notification, Shipper shall be obligated to adjust its receipts and deliveries

to correct or avoid any imbalance between nominations and actual receipt or

delivery. Any adjustment to receipts and deliveries by Shipper, whether or

not pursuant to notification from Southern Trails, shall be coordinated with

Southern Trails' Customer Service representatives and in accordance with

Southern Trails' scheduling procedures.

15.2 Daily Operating Tolerance. A Shipper must maintain a daily

thermal balance between receipts and deliveries within the ± 2.5% daily

imbalance tolerance.

Southern Trails will notify a Shipper upon determination that the

Shipper's receipts and deliveries exceed the ± 2.5% daily imbalance tolerance.

After notification by Southern Trails that an adjustment is necessary to keep

its system in balance, a Shipper will be afforded reasonable opportunity to

remedy its imbalance consistent with existing operational conditions. If the

imbalance is not corrected within the time specified, Southern Trails will

take whatever action it deems necessary to remedy the imbalance situation.

Southern Trails will make daily imbalance information available through

Questline each day for the prior gas day.

If required to maintain operational stability and system integrity,

Southern Trails will adjust all receipts and deliveries on its system, even if

Shippers are within the ± 2.5% imbalance tolerance limits.

Adjustments at each transmission transfer meter will be made according

to the applicable Operational Balancing Agreement (OBA) or pre-determined

allocation arrangement (PDA) with operators upstream and downstream of

Southern Trails' transmission system. Absent an OBA or PDA, adjustments will