Antero Resources’ Mitigation Strategies and Best Management Practices: Wolf Springs, Mesa County (TPD1204025)

Fugitive Dust

• Well pad location and access roads graveled to reduce dust impacts
• Soiltac and/or liquid dust suppressants are used to mitigate fugitive dust emissions on access roads and well pad location
• Buried water lines to minimize fugitive dust emissions from truck traffic
• Limiting vehicle speeds during well pad location site access
• Road sweeping to reduce fugitive dust and mud tracking onto roadways where practicable

Groundwater and Surface Water Resources

• Closed loop (pitless) drilling systems; no reserve, drill cuttings or frac/flowback pits will be constructed
• Water used for well completions will be recycled as practicable
• Frac/Flowback tank area lined and/or tanks equipped with portable spill berm containment structures
• Production tank containment area bermed and lined with plastic
• Well pad location perimeter berms to contain unintended fluid releases
• Voluntary Water Well Testing Program
  • Pre – all water wells/springs within ½ mile radius of the surface-hole location for each well on a well pad location
  • Post – within one year a follow-up test on the pretest wells/springs or when all wells drilled and completed on a well pad location
  • Where practical water quality testing as requested by landowner for water wells, springs, potable water and agriculture water
  • Comply with provisions of water well testing in surface use agreements
• Wetland/drainage survey and mapping conducted prior to site disturbance
• Containment for well pad location within 500 feet of surface water is 110 percent secondary containment for any volume of fluids contained at a well pad location during drilling and completion operations

Planning Infrastructure and Development Activities which Minimize Impact

• Antero setbacks of 500 feet from dwelling units – COGCC setbacks are 150-200 feet
• Well pad location construction not to exceed 3.5 acres
• Bury all gas and water pipelines adjacent to roads whenever possible
• Water used for well completions will be recycled as practicable
• Above-ground facilities located to minimize visual effects (e.g. production tanks will be low profile tanks and painted to mitigate visual impacts)

Spill Prevention, Control and Countermeasure (SPCC Program)

• Annual SPCC Training
• SPCC inspections conducted quarterly
• Well pad location perimeter berms will be constructed
  • Purpose is to provide tertiary spill containment for production tanks and separators
  • Provides secondary spill containment for all material activities on site not just oil storage.
  • Provides a barrier between well pad location activities and surrounding areas
• Frac/Flowback tank area will be located in an area with down gradient well pad location perimeter berm

• Frac/Flowback tank area lined to mitigate seepage losses from the unintended spillage of well completion fluids, or frac/flowback tanks will be placed in portable spill berms
• Standard Operating Procedures (SOPs) training performed for handling and transfer of frac/flowback and produced fluids
• High level overflow alarms installed on production tanks
• Covered drip buckets for condensate and produced water tanks and loadout lines
  • Purpose is to minimize spillage and drips that occur during normal loading activities
  • Designed to catch residual liquids that remain in lines after the tank valves and truck valves have been closed
  • Covers minimize VOC emissions and exposure to storm water

Stormwater Management

• Facilities operated with a Water Quality Control Division (WQCD) stormwater construction permit
• Stormwater BMPs in accordance with the Stormwater Management Plan will be implemented in a manner that minimizes erosion, transport of sediment offsite, and site degradation
• Inspections will be conducted every two weeks/monthly and after a precipitation or runoff event in accordance with WQCD General Permit to confirm that applicable BMPs are in place, maintained and functioning properly
• Straw wattles and erosion blankets or other suitable erosion control devices are used to prevent sediment from leaving the site
• Site Preparation conducted to establish stable slopes, water courses and drainage features to minimize erosion and sedimentation

Invasive Non-Native Vegetation Control

• Weed management plan will be developed and implemented to monitor and control noxious and invasive weeds
• Noxious weed control includes three treatments per year
• Existing weed infestations will be mapped prior to the development of each pad, access road and pipeline when practicable
• Reclamation/revegetation will be used as a weed management tool