Antero Resources Battlement Mesa Natural Gas Development Plan Meeting 7 (TPD0910034)

Today’s Meeting Purpose

• Review Major Aspects of Environmental Program

–     Air Quality and Odor Mitigation

–     Surface Water Resource Protection

• Spill Prevention
• Stormwater/Erosion Control

–     Mitigation Strategies

• Noise
• Dust
• Light
• Weeds
• Visual/Aesthetics
• Question and Answer Session

Slide 3

Air Quality Modeling Study – Brief Overview

• What are the major potential emission sources involved in natural gas development?Temporary

–      Truck Traffic and Construction of Pads and Pipelines – fugitive dust

• Controls = reduce traffic (water pipeline), gravelling pads and dust suppression via water/Soiltac®

–      Drilling Rig Generators – diesel fumes and exhaust emissions

• Controls = electric grid power-substitute for diesel generators, low NOX engines where grid unavailable

–      Drilling Reserve Pits

• Controls = pitless drilling

–      Fraccing Operations – diesel fumes and exhaust emissions, flowback tanks

• Controls = Green completion skids and covered flowback tanks

Long Term

–      Production Tanks – VOC emissions from condensate flashing (> 90% of potential)

• Controls = Combustor flare controls and automatic igniters

–      Separators and Wellheads – fugitive VOC emissions from valves and flanges

• Controls = Low bleed valves and routine maintenance of connection integrity

–      Water Handling Facility – VOC and bacterial odors

• Controls = Eliminate through use of covered pit design and vapor collection/combustion

Slide 4

Air Quality Modeling Study – Brief Overview

• What did Antero model and why?
  • The community expressed concerns about air quality

−    Expansion of voluntary Antero programs

• Antero modeled VOC emissions from production tanks because:

–          Continuous source of emissions over the productive life of a natural gas well

–          Uncontrolled emissions can be relatively significant compared to the other emission sources

• Purpose of modeling study

−   To identify and evaluate the potential air quality impacts at nearby residences from production tanks at planned well pads

Slide 5

Air Quality Modeling Study – Brief Overview

• Potential Air Quality Impacts

–      EPA approved air model (AERMOD) used to estimate air quality impacts

–      Air Quality Impacts = Predicted benzene concentrations around well pads

–      EPA model used Rifle Airport meteorological data and worst case production tank emission rates

• Modeled Benzene Concentrations

–      Compared to EPA Health Based Standards and

–      Colorado Air Monitoring Data

• Conclusion – Modeled Worst Case Benzene Concentrations at Nearby Residences Are Significantly Below EPA Health Based Standard

Slide 6

Modeling Inputs – Worst Case Emissions Scenario

• Assumptions

–        No tank emission controls

–        Up to 20 wells on a completed pad (2x Antero actual dev. plans)

–        11 proposed pads

–        1.78 bbls condensate per MMscf  (Grand Valley and Parachute Field)

–        Each well makes 2 MMscf/day

–        Each pad was modeled assuming 75 bbls/day condensate

• Antero Tank Emission Factor

–        EPA Approved Model (E&P Tanks 2.0) –  Used  to determine condensate tank VOC/benzene emission rates

–        Uncontrolled Benzene emissions ~ 0.36 tpy from each well pad

–        Uncontrolled Emission Factor = 0.026 lbs benzene/bbl condensate

Slide 7

Modeling Inputs – Worst Case Emissions Scenario (cont.)

• Why Model Worst Case Uncontrolled Emission Scenario?

–        Actual production tank well pad emissions controlled by flare with potential to be fitted with auto igniter

–         Actual modeled emissions (controlled) will be significantly less than worst case modeled emissions (uncontrolled)

–         If worst case modeled benzene concentrations are below EPA health based standards then actual benzene impacts will be significantly less

Modeling Inputs – Meteorology

• Used a Rifle Airport 5-yr meteorological dataset
• Rifle Airport dataset provided by Colorado Department of Public Health & Environment (CDPHE)
• Rifle Airport – Wind direction/speed data

–      Most representative of Battlement Mesa meteorological conditions

–      Prevailing wind direction are from west and south (see Rifle Airport Wind Rose Slide)

• Rifle Airport – Terrain influences

–      Similar to Battlement Mesa

–      Both locations immediately south of river and I-70

–      Rifle Airport at 5,500 ft, Battlement Mesa at 5,100 to 5,500 ft

• Closet meteorological dataset is Williams’ Parachute Creek Gas Plant (PCGP), however it was not used because:

–       Located in Grand Valley oriented NW to SE

–       PCGP Wind Rose shows prevailing winds parallel to Grand Valley

–       Dataset limited to 1-yr

Slide 9

Air Quality Modeling – Predicting Impacts from Well Pad Production Tanks

• Modeled potential offsite impacts at “Receptors” out to 1,500 feet in all directions from each well pad location

• Receptor = residence, golf course clubhouse, schools, etc.

• Impacts = Modeled 24-hr Benzene Concentrations

• Identified location of Potential Maximum 24-hr impacts relative to each pad location

• Modeled Results – See Area Specific Well Pad Impact Maps

–      Area specific maps include setback distances

• 350 ft – COGCC Setback in high density areas
• 500ft – Antero Internal Setback
• 1,000 ft

Slide 11

Benzene Air Quality Data – Monitored

• Compared modeled worst case uncontrolled 24-hr benzene concentrations to monitoring data in Denver, Grand Junction and Piceance Basin.

• Average monitored 24-hr benzene concentrations

–           Denver = 2.5 to 3.2 µg/m3   (data collection follows EPA monitoring protocols)

–           Grand Junction = 1.6 µg/m3  (data collection follows EPA monitoring protocols)

–           Parachute = 3 µg/m3 (likely less than 3 µg/m3 because benzene “non-detects” not counted – Garfield County monitoring data)

• Benzene monitoring data for Colorado are presented in following table

Location

24-hr Conc. (ug/m³)

Average

Maximum

¹Denver – Urban Site 1

3.2

7.4

¹Denver – Urban Site 2

2.5

7.2

¹Denver – Urban Site 3

2.8

7.0

²Grand Junction (Powell)

1.6

4.2

Glenwood – Courthouse

1.2

3.5

New Castle – Library

2.0

15.0

Rifle – Henry Bldg

2.9

6.9

Parachute

3.0

5.1

Silt – Cox

1.0

1.9

Silt – Bell

2.0

7.4

Butterfly

2.0

7.7

Isley

1.2

3.0

West Landfill

4.4

7.5

Sebold

1.1

2.7

Haire

1.0

2.3

Benzene Air Quality Data – Modeled

–       Worst case modeled benzene concentrations were compared to:

• EPA acceptable 24-hr exposure of 30 µg/m3 = benzene health based standard (U.S. EPA. Integrated Risk Information System (IRIS) on Benzene. National Center for Environmental Assessment, Office of Research and Development, Washington, DC. 2002)

–       Residential (receptor) locations are all below the EPA standard of 30 µg/m3

–       9.2 µg/m3 was the highest modeled 24-hr concentration (house north of N Pad). (maximum out of 365 X 5 yrs = 1825 days)

–       Background benzene 24-hr concentration of 3 µg/m3 in Parachute was added to modeled results for comparison to the health based 24-hr standard.

–       Maximum Modeled benzene 24-hr concentrations for each well pad are presented in the next slide.

Antero Resources – All Proposed Production Pads

Table 1: AERMOD Modeled Benzene Impacts from Uncontrolled Tank Emissions

– Rifle Garfied County Airport Meteorological Data

Maximum Modeled Benzene Concentrations (µg/m3)

Distance to Sensitive Receptor (feet)

Closest Sensitive Receptor²

Average of Monitored Benzene Samples

collected in Parachute

Total

Comparison To Acceptable Health-Based Threshold Concentrations (µg/m3)

Pad Location

24-hr (acute)

24-hr Background

Acute (24-hr) – EPA¹

Acute (24-hr) – Utah TLV²

Pad N

~615′

6.17

3.0

9.2

30 (µg/m³)

53 (µg/m3)

~515′

0.67

3.0

3.7

Watson Pad

~680′

0.90

3.0

3.9

Pad A

~529′

0.55

3.0

3.6

Pad B

~585′

0.80

3.0

3.8

Pad C

~535′

3.79

3.0

6.8

Pad D

~540′

3.10

3.0

6.1

Pad E

~730′

1.56

3.0

4.6

Pad G

~1030′

1.65

3.0

4.7

Pad K

~2600′

0.24

3.0

3.2

Pad L

~1056′

4.52

3.0

7.5

Pad M

~745′

1.20

3.0

4.2

** Acute exposures are considered short-term 24-hr exposures

1 EPA accepted standard for short-term exposures below which no inhalation health impacts are anticipated