# R ESOLUTE

N ATURAL 

### R ESOURCES



### for Resolute Natural Resources Company 1675 Broadway, Suite 1950 Denver, CO 80202



# McElmo Creek Unit Oil Production Facility - Main Flare, Gas Compression Facility PSD Permit Application and Support Document Resolute Natural Resources Company

Revised April 2008 MMA Project Number 2220-08

by McVehil-Monnett Associates, Inc.

44 Inverness Drive East, Building C Englewood, CO 80112

### i TABLE OF CONTENTS

Page No. in Section



### 1.0 INTRODUCTION ............................................................................................... 1 1.1 GENERAL INFORMATION ...................................................... .................1 1.2 PERMIT APPLICATION ..............................................................2 2.0 PROJECT DESCRIPTION............................................................1 2.1 FACILITY AIR QUALITY PERMIT HISTORY ........................................... 1 2.2 EXISTING FACILITY OPERATIONS ........................................................... 2 2.3 MODIFICATION ................................................................................................ 3 2.4 MAIN FLARE REGULA TORY REQUIREMENTS ...................................... 3 2.4.1 New Source Review ............................................................................................... 3 2.4.2 Consent Decree Requirements ............................................................................. 4 2.4.3 New Source Performance Standards (NSPS) and National Emission Standards for Hazardous Air Pollutants (NESHAP) ....................................... 4 2.4.4 Other Air Quality Requirements ......................................................................... 5 2.4.5 Title V Requirements ............................................................................................ 5 3.0 MAIN FLARE EMISSIONS .............................................................................. 1 3.1 CRITERIA POLLUTANTS ............................................................................... 2 4.0 BEST AVAILABLE CONTRO L TECHNOLOGY ANALYSIS ................... 1 4.1 ALTERNATIVE CONTROLS ON FLARES .................................................. 2

4.1.1 Volatile Organic Compounds (VOC) ..................................................2 4.1.2 Carbon Monoxide (CO) ...................................................................................... 5 4.1.3 Nitrogen Oxides (NO x 

### ) ........................................................................................ 6 4.1.4 Sulfur Dioxide (SO 2 

### ) ............................................................................................ 8 4.2 COMPRESSOR ENGINE MODIFICATIONS ......................................9 4.2.1 Past Flaring Due to Compressor Downtime ..........................................9 4.2.2 Options to Improve Reliability of HOS-6 Compressor Engine Operations ..10 4.2.3 Other Compressor Changes ...........................................................11 4.3 FLARE GAS RECOVERY SYSTEMS ..............................................12 4.4 OPERATION & MAINTENANCE (O&M) PLAN .............................. 14 5.0 EXISTING ENVIRONMENT ............................................................................ 1 5.1 TOPOGRAPHY .................................................................................................. 1 5.2 AIR QUALITY .................................................................................................... 1 5.3 AREA CLIMATE AND METEOROLOGY .................................................... 2 5.4 SOILS AND VEGETATION ............................................................................. 4 6.0 IMPACT ASSESSMENT APPROACH ............................................................ 1 6.1 AIR QUALITY MODEL DESCRIPTION ....................................................... 2 6.2 MODEL INPUT .................................................................................................. 3 6.3 METEOROLOGICAL DATA ........................................................................... 3 6.4 SOURCE CHARACTERISTICS AND EMISSION RATES ......................... 4 6.4.1 Fuel Rate and Heat Release ................................................................................. 4

### ii 6.4.2 Flare Height ........................................................................................................... 5 6.4.3 Modeled Emission Rates ...................................................................................... 5 6.5 RECEPTOR SELECTION ................................................................................ 6 6.6 CLASS I AREA IMPACTS .............................................................6 6.7 ADDITIONAL IMPACTS ..............................................................7 6.8 ENDANGERED SPECIES ..............................................................8 7.0 AIR QUALITY IMPACTS ................................................................................. 1 7.1 NITROGEN DIOXIDE (NO 2 

### ) ............................................................................ 2 7.1.1 Increment Consumption ....................................................................................... 2 7.1.2 National Ambient Air Qu ality Standards (NAAQS) ......................................... 3 7.2 SULFUR DIOXIDE (SO 2 

### ) .................................................................................. 3 7.2.1 Increment Consumption ....................................................................................... 4 7.2.2 National Ambient Air Qu ality Standards (NAAQS) ......................................... 4 7.3 CARBON MONOXIDE (CO) ............................................................................ 6 7.3.1 National Ambient Air Qu ality Standards (NAAQS) ......................................... 6 7.4 CLASS I AREA IMPACTS ..............................................................7 7.4.1 Class I Increments .........................................................................7 7.4.2 Visibility ......................................................................................8 7.4.3 Deposition ....................................................................................8 8.0 REFERENCES ......................................................................................1

LIST OF TABLES

TABLE 3-1 PRE-PROJECT & POST-P ROJECT ACTUAL & PTE EMISSIONS TABLE 3-2 MAIN FLARE CRITERI A POLLUTANT EMISSION LIMITS TABLE 4-1 BACT/LAER CLEARINGHOUSE DATABASE SUMMARY -VOC TABLE 4-2 BACT/LAER CLEARINGHOUSE DATABASE SUMMARY -CO TABLE 4-3 BACT/LAER CLEARINGHOUSE DATABASE SUMMARY -NOx TABLE 4-4 BACT/LAER CLEARINGHOUSE DATABASE SUMMARY – SO 2 

### TABLE 4-5a McELMO GAS COMPRE SSION FACILITY – CHANGE HOS-6 COMPRESSOR PROCESS CAPITAL COST SUMMARY TABLE 4-5b McELMO GAS COMPRE SSION FACILITY – CHANGE HOS-6 COMPRESSOR PROCESS OPERATING COST SUMMARY TABLE 4-6a McELMO GAS COMPRE SSION FACILITY – REPLACE HOS-6 COMPRESSOR CAPITAL COST SUMMARY TABLE 4-6b McELMO GAS COMPRE SSION FACILITY – REPLACE HOS-6 COMPRESSOR OPERATING COST SUMMARY TABLE 4-7a McELMO GAS COMPRESSION FACILITY – FLARE GAS RECOVERY SYSTEM CAPITAL COST SUMMARY TABLE 4-7b McELMO GAS COMPRESSION FACILITY – FLARE GAS RECOVERY SYSTEM OPERATING COST SUMMARY TABLE 5-1 AIR QUALITY IN THE MCELMO CREEK AREA

### iii TABLE 5-2 JOINT FREQUENCY DISTRIBUTION OF BLANDING, UTAH TABLE 5-3 ANNUAL STABILITY CLA SS DISTRIBUTION AT BLANDING,UT TABLE 5-4 MONTHLY AVERAGE TEMPERATURE & TOTAL PRECIPITATION TABLE 6-1 SUMMARY OF NATIONAL AMBIENT AIR QUALITY STANDARDS & PSD INCREMENTS TABLE 6-2 SCREEN3 MODELED ST ACK PARAMETERS & EMISSIONS FOR THE MAIN FLARE TABLE 7-1 COMPARISON OF MODELED MAIN FLARE NO 2 

### IMPACTS TO THE PSD INCREMENTS TABLE 7-2 COMPARISON OF MODELED CUMULATIVE NO 2 

### IMPACTS TO THE NAAQS TABLE 7-3 COMPARISON OF MODELED MAIN FLARE SO 2 

### IMPACTS TO THE PSD INCREMENTS TABLE 7-4 COMPARISON OF MODELED CUMULATIVE SO 2 

### IMPACTS TO THE NAAQS TABLE 7-5 COMPARISON OF MODELED CUMULATIVE CO IMPACTS TO THE NAAQS TABLE 7-6 CLASS I AREA AMBIENT AIR IMPACTS TABLE 7-7 CLASS I AREA DEPOSITION IMPACTS

LIST OF FIGURES

FIGURE 2-1 LOCATION MAP OF McELM O CREEK OIL PRODUCTION FACILITY FIGURE 2-2 FLOW DIAGRAM OF EXISTI NG GATHERING SYSTEM OPERATIONS FIGURE 2-3 BLOCK FLOW DIAGRAM OF GAS COMPRESSION PLANT FIGURE 5-1 WIND ROSE OF 2004 BLAN DING, UTAH METEOROLOGICAL DATA

LIST OF APPENDICES

APPENDIX A EXXONMOBIL MCEL MO CREEK OIL PRODUCTION UNIT CONSENT DECREE APPENDIX B DERIVATION OF ESTIMA TED PRE-PROJECT AND POST-PROJECT ACTUAL AND POTENTIAL TO EMIT EMISSIONS APPENDIX C SCREEN3 MODELING INPUT AND OUTPUT RESULTS APPENDIX D E-MAILS FROM MR. JO HN NOTAR of the NATIONAL PARK SERVICE and MR. HENRY MADDUX, UTAH ENDANGERED SPECIES SUPERVISOR APPENDIX E SCREEN3 AND VISCR EEN PRINT-OUTS FOR CLASS I AREA IMPACTS

### 1-1 1.0 INTRODUCTION

1.1 GENERAL INFORMATION

Resolute Natural Resources Company (Resolute) is submitting this revised Prevention of Significant Deterioration (PSD) pe rmit application for its Main Flare at the McElmo Creek Oil Production Facility, located on th e Navajo Nation near Aneth, Ut ah. This revised PSD permit application is submitted to meet the terms of a Consent Decree (DOJ Case No. 90-5-2-1-2237, filed June 8, 2005) issued to the previous owner/operator of the facility, ExxonMobil Corporation (ExxonMobil). No modification is proposed with this pe rmit application.

ExxonMobil installed an automatic air-assisted system on the Main Flare on May 8 – 12, 2006, pursuant to the provisions of 40 CFR § 60.18 (c)(5) and (f)(6), as required in Paragraph 11.b of

its Consent Decree.

This PSD permit application doc ument presents a facility process description for existing operations, criteria pollutant permit emission limits for the Main Flare, a Best Available Control Technology (BACT) analysis fo r the Main Flare, air modeling methodology, and air modeling results. Impacts are evaluated in both Class I and II areas.

This permit application contains informa tion submitted on March 22, 2007 with revisions intended to respond to recent EPA Region IX comments concerning increased emissions due to processing flare gas with a higher BTU c ontent than previously cited. Specific additions/revisions to the application document submitted on March 22, 2007 in response to EPA Region IX comments include:

1. Emissions Data: Post-project potential to emit (PTE) emissions have been reestimated per EPA’s request to estimate th e maximum post-project PTE for all criteria pollutants, using the higher BTU content values tested during 2005-08 operations. Section 3.0 presents a summary of previous ly estimated pre- a nd post-project actual emissions and pre-project PTE and revised post-project PTE. Appendix B contains detailed emission calculations and fuel gas co mposition used to provide these estimates. These calculations include the basis for the revised post-project PTE estimates.

### 1-2 2. BACT Analysis: The Top-Down BACT analysis presented in Section 4 has been revised to consider the re-estimated post-project PTE for all criteria pollutants and to address the potential range of control effici encies provided by compressor improvements. The cost effectiveness analys es presented in Tables 4-5 through 4-7 were revised to consider the higher estimates of post-projec t PTE for each criteria pollutant and the maximum control efficiency estimated for compressor improvements.

Description of BACT, Class I area, addition al impacts and endangered species analyses presented in the March 22, 2007 submittal have been retained to provide for an all-inclusive support document of PSD review and analyses performed for this permit application.

1.2 PERMIT APPLICATION FORM

A completed permit application form providing information on the existing facility, including the Main Flare, is attached at the end of this sec tion. Flare specification sheets are attached after the permit application form to provide inform ation on flare manuf acturer and model.

### PSD Permit Application Form Page 1 of 4



### General Information Company Name and Address: Resolute Natural Resources Company 1675 Broadway, Suite 1950 Denver, CO 80202 Phone No.: 303-534-4600 Fax No.: 303-623-3628 Company Contact for En vironmental Matters: Patrick E. Flynn Environmental Health & Safety Manager 1675 Broadway, Suite 1950 Denver, CO 80202 Phone No.: 303-534-4600 Fax No.: 303-623-3628 Facility Name and Address: McElmo Creek Unit Oil Production Facility P.O. Box 100130 Aneth, UT 84510

Phone No.: 303-534-4600 Fax No.: 303-623-3628 Owners Name and Address : Resolute Natural Resources Company 1675 Broadway, Suite 1950 Denver, CO 80202 Phone No.: 303-534-4600 Fax No.: 303-623-3628

County where facility is located: San Juan Latitude and Longitude or UTM coordinates: 37 o 15' 37.58" N 109 o 12' 12.07" W

Directions to facility (street add ress and/or directions to site): From Cortez Airport, take Hwy 160 South for 30 miles. Turn right (heading Northwest) on CO 41 to Utah. CO 41 turns into UT 262 at the state line. Continue on UT 262 for 14 miles, through the town of Aneth. Turn Right at the Resolute sign and follow the road 3.1 miles to the office. The office is on the left and the gas compression plant is on the right. List current air quality permits for facility: U.S. EPA Region VIII PSD Permit 8AT-AP (last amended April 18, 1991)

If request for a modification, identify permit # to be modified: Permit No.: 8AT-AP Dated: April 18, 1991 Type of business at this facility: Oil & Gas Production Are the total number of company employees greater than 100? Yes Standard Industrial Code Classification : 1311

Application for: ___ New construction X Modification

X Existing equipment operatin g without permit ___ Permanent site for portable equipment ___ Change of permit condition ___ Change of location

For new construction or modification, enter estimated start date : Flare Upgrade will begin in March 2006 estimated completion date : Must be completed by June 8, 2006 For change of permittee, location, or condition, enter date of occurrence: N/A For existing equipment in operation without prior permit, enter initial operation date : 1991

### PSD Permit Application Form Page 2 of 4



### Process Information Name of process: Oil & Gas Production; Gas Dehydration and Compression; CO2 and Water Injection End product of this process: Oil

Primary process equipment: Separators, Heaters, Tank Batteries, De hydration System, Compressors, and Flare



### Operating Data Maximum Operating Schedule: 24 hours/day

7 days/week 52 weeks/year Percent annual produc tion by quarter: Winter 25% Spring 25% Summer 25% Fall 25%

Daily production rates: Average: 3,700 bopd Maximum: 5,000 bopd Maximum annual production: 1,825,000 bbls of oil Projected percent annual increase in production: N/A Type of operation: X Continuous

__ Batch

__ Intermittent If batch, indicate minutes per cycle: N/A Minutes between cycles: N/A

Materials used in process: (1) raw material, (2) principal use, and (3) amounts: 3,700 bbls of oil produced (bop) and sold each day on average from the tank batteries 26,000 bbls of water produced (bwp) and injected each day on average 10-18 million cubic feet of gas produced each day on average 6-14 million cubic feet of CO2 is purchased each day to supplement injection to 24 million total cubic feet per day

### PSD Permit Application Form Page 3 of 4



### Flare System Information

Manufacturer: Zeeco, Inc. will perform upgrade in March 2006; Originally by American Steel and Iron Works

Model No: N/A Fuel Minimum Expected Flowrate Design Max Temp oF Pressure (psig)

Waste gas stream: Dehydrated Produced Gas (approx. 70% CO2 and 0.05% H2S) - Up to 14 million cubic feet per day Fuel added to gas stream: N/A

Heat Content of flared gas 500-682.4 BTU/scf Number of pilots: Currently 1 Pilot fuel type : Natural Gas Pilot fuel flow rate, per pilot (scfm 70oF & 14.7 psia): 1.0 Flare height : Currently 195 feet Flare tip inside diameter: 24 inches

Steam Injection NA Steam pressure (psig): NA Minimum expected: NA Design maximum: NA Total steam flowrate (lb/hr): NA Temperature (oF): NA Velocity (ft/sec): NA Number of jet streams: NA Diameter of jet streams (in.): NA

Water Injection: Water pressure (psig): NA Minimum expected: NA Design maximum: NA Total water flowrate (gpm): NA Minimum expected: NA Design maximum: NA Number of water jets: NA Diameter of water jets (in.): NA

Air Assist: Air pressure (psig): Minimum expected: Design maximum: Total air flowrate: Currently in Design Velocity (ft/sec): Number of air jets: Diameter of air jets (in.):

### PSD Permit Application Form Page 4 of 4



### Certification Statement

I certify under penalty of law that I have examined and am familiar with the information submitted in this document and all attachments and that this document and its attachments were prepared either by me pers onally or under my direction or supervision in a manner designed to ensure that qua lified and knowledgeable personnel properly gathered and presented the information contai ned therein. I furthe r certify, based on my personal knowledge or on my inquiry of t hose individuals immediat ely responsible for obtaining the information, that the informati on is true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fines and imprisonment for know ing and willful submi ssion of a materially false statement.

Signature:_____________________________________ Date:___________

Name (type): Dale E. Cantwell

_____________________ Title: Vice President, Operations

Phone:_303-534-4600

_______________________________________

### 2-1 2.0 PROJECT DESCRIPTION

This section presents an overview of the Mc Elmo Creek Oil Production Facility, including a summary of the facility’s air permit histor y, overview of operations including the gas compression plant and the Main Flare, and a review of applicable air quality requirements.

2.1 FACILITY AIR QUALITY PERMIT HISTORY

The McElmo Creek Oil Production Facility is lo cated in San Juan County, Utah near Aneth, Utah in Section 23 of T40S, R24E on Navajo Nation land. A location map of the facility is presented in Figure 2-1.

The original oil well production fa cility, owned by Superior Oil, started operations in the 1950s. Mobil Exploration and Producing U.S., Inc. (Mobil) purchased the facility from Superior Oil in 1984. In 1986, Mobil constructed a gas processing pl ant at the facility, including an upright flare, dehydrator, amine treater, refrigeration se paration unit, a natural gas liquids recovery unit and compressors to transport the produced liqui d natural gas. In 1991, the equipment was switched out with an emergency flare added as a control device for the dehydrators. Petroleum liquid storage tanks and heater treat ers were also installed in the early 1990s. At that time, the emergency flare was not permitted because it was viewed as an emergency control device. The permit and facility operations have been overseen by EPA Region IX. EPA has delegated oversight authority of this facility since it is on tribal land and is assisting the tribe in administering its recently approved regulatory program.

In 1997, following a fire, all processing equipment except for one dehydrator was removed, the compressors were converted to r un on electricity, and the flare wa s kept for emergency flaring, flaring closed drain system fumes, and control of dehydrator emissions. The former gas processing plant is now referred to as the gas compression plant.

In 1997 and 1999, EPA issued NOVs (Notice of Violat ions), asserting the fl are should have been permitted. The NOVs also cited the lack of fugitive VOC (volatile organic compounds) monitoring per the New Source Performance St andards (NSPS) of 40 CFR 60, Subpart KKK.

### 2-2 The following is a summary of the PSD permit hi story associated with the McElmo facility:

• March 14, 1985 - U.S. EPA Region VIII determ ined Stage I of McElmo Creek Unit does not require a PSD permit;

• May 8, 1986 - Mobil Exploration and Producing North America submitted PSD Permit Application for CO 2 

### Project Stage 2;

• February 2, 1987 - U.S. EPA Region VIII issued PSD permit to Mobil;

• September 1, 1987 - Mobil submitted letter re questing to replace three reciprocating internal combustion engines with two natural gas fueled turbines;

• October 27, 1987 - U.S. EPA Region VIII issu ed amended PSD permit for the change;

• February 21, 1991 - Mobil requested amendmen t of PSD permit to a llow construction of waste heat recovery unit turbine, replac ing two existing pieces of fuel-burning equipment;

• February 22, 1991 - Mobil requested EPA appr oval for temporary replacement of turbine with an identical unit, during turbine overhauls;

• April 18, 1991 - U.S. EPA Region VIII issues amended PSD permit for requested changes and also, rescinded approval of the second turbine since Mobil had no plans to

install it.

Resolute acquired ExxonMobil’s ow nership interest in the McEl mo facility in April 2006 and assumed operation effective June 1, 2006

2.2 EXISTING FACILITY OPERATIONS

Currently, produced fluids at the oil production facility are processed, sold, and re-injected through a series of satell ite facilities, main tank batteries, and injection plants. Produced fluids are gathered and separated at one of eleven satellite facilities located throughout the field. Gases

from the satellite facilities are directed to the gas compression plant, and liquids are pumped to

one of four central tank batteries . Gases sent to the gas compression plant are compressed, dried through a glycol dehydrator, ble nded with carbon dioxide (CO 2 

### ), and re-injected into the field. Liquids are further separated at the central tank batteries, with oil being sold and transported through a pipeline system. Water from the central tank batteries is pumped to the water flood injection plant.

### 2-3 The Main Flare at the gas compression plant co mbusts gases that have been bypassed around the plant’s electric-driven compressors or that come through various em ergency relief valves in the compression plant. Additionally, the vent stream from the plant’s glycol dehydrator is directed

to the Main Flare.

A flow diagram of the facility’s gathering sy stem operations is presented in Figure 2-2, illustrating the flow through the sa tellite facilities, central tank batteries, water flood injection plant, and gas compression plant. Figure 2-3 pres ents a simple block flow diagram for the gas compression plant, including the stre ams directed to the Main Flare.

2.3 MODIFICATION

As noted in Section 1, no modification of existi ng operations is proposed with this PSD permit application. This application is submitted in or der to meet the requirements of a Consent Decree (DOJ Case No. 90-5-2-1-2237, file d June 8, 2005) issued to th e former owner, ExxonMobil. Paragraph 14.a requires ExxonMobil to submit an application for a PSD permit for the Main Flare, including “(i) an analysis of the best av ailable control technology for the Main Flare for [sulfur dioxide] SO 2 

### , [carbon monoxide] CO, [nitrogen oxide s] NOx, and [volatile organic compounds] VOC; and (ii) an air quality analysis ” within 180 days of the Consent Decree’s effective date of June 8, 2005.

2.4 MAIN FLARE REGULA TORY REQUIREMENTS

2.4.1 New Source Review

No modifications are being proposed to necess itate a PSD permit application. However, the Consent Decree requires a PSD pe rmit application submittal for the Main Flare, including a BACT analysis for SO 2 

### , CO, NOx, and VOC, and an air quality analysis to assess the impacts of

the Main Flare’s criteria emissions to ambient ai r quality standards. Based on EPA Region IX’s comments in their May 22, 2006 letter, assessment of the Main Flare’s emissions consider BACT criteria and impacts on Class II areas are modeled. Class I area impacts, additional impacts and effects on endangered species are not formally assessed per telephone and e-mail correspondence

### 2-4 with Mr. Notar of the National Park Servi ce and Mr. Henry Maddux, Utah Endangered Species Field Supervisor.

Consent Decree Requirements

The Consent Decree further requires in Paragr aph 14.a that the PSD application include “among other things, terms and conditions that are at least as string ent as the terms and conditions included in Paragraphs 9.a, 10, 11, and 25(i)-(ix) of this Consent Decree, with the exception that the quarterly report required by Paragraph 25 may be changed, at the discretion of the permitting authority, to a semiannual report.” Paragraph 9.a of the Consent Decree refers to the rolling 365- day cumulative emission limits for SO 2 

### , CO, NOx, and VOC, which will be discussed in Section 3 of this application document. Paragraph 10 of the Consent Decree addressing monitoring requirements for the Main Flare, and Paragr aph 11 presents operation and maintenance requirements for the Main Flare and compressors at the gas compression plan t. Paragraph 25 of the Consent Decree details a quarterly reporting system, the frequency of which may be changed by the permitting authority, as noted earlier. A c opy of the Consent Decree has been attached as an appendix to this application. The air permit for the Main Flare will contain the terms and conditions found in Paragraphs 9.a, 10, 11, and 25( i)-(ix) of the Consent Decree either by reference or by direct incl usion in the permit.

2.4.2 New Source Performance Standards (NSPS) and National Emission Standards for Hazardous Air Pollutants (NESHAP)

The Consent Decree specifies recordkeeping, maintenance, and operational procedures to demonstrate a 98 percent destruction effi ciency on VOCs consistent with 40 CFR § 60.18 (NSPS) and 40 CFR § 63.11 (NESHAP). These procedures and limitations are a pplicable to a

flare used as a control device for affected faci lities subject to individual NSPS and/or NESHAP subparts. Such is not the case here. Rather, the Main Flare at the McElmo Creek Gas Plant has been typically used as an emergency flare to co ntrol process gas and waste gas release emissions when the injection system (the primary cont rol “device”) is malfunctioning and/or undergoing maintenance. As such, it is the Consent De cree alone that compel s the flare destruction efficiency requirement.

### 2-5 2.4.4 Other Air Quality Requirements

Since the facility is lo cated on the Navajo Nation, it is the Navajo Nation, and not the state of Utah that has the authority (aside from EPA) to implement air quality programs relevant to the facility. Although the Navajo Na tion has been granted delegated authority as of October 15, 2004, EPA is acting as an oversight reviewi ng agency assisting the Navajo Nation in administering their approved program.

2.4.5 Title V Requirements

A Title V operating permit application must be submitted, as required by Paragraph 14.b of the Consent Decree, no later than 180 da ys after the Consent Decree’s e ffective date of June 8, 2005. Similar to the requirements for the PSD permit application, the Title V operating permit application must include terms and conditions at least as stringent as those in Paragraphs 9.a, 10, 11, and 25(i)-(ix) of the Consent De cree, with the exception that the quarter ly report described at Paragraph 25 may become a semiannual report.Figure 2-2Block Flow Diagram of ExistingGathering System OperationsMcElmo Creek Oil Production Unit

### 3-1 3.0 MAIN FLARE EMISSIONS

As requested in the EPA Region IX comment lett er of May 22, 2006, this se ction presents preand post-project actual emissions, as well as pre- project estimates of the potential to emit (PTE) for all criteria pollutants, including particulate matter (PM 10 

### and PM 2.5 

### ) and lead. Pre- and postproject gas flow rates to the flare are also incl uded. Per EPA’s comment letter, pre-project is defined as prior to the gas compression facility being dismantled in 1997, and post-project is defined as subsequent to the gas plant being dismantled. Thus, pre-project emission estimates provided in Table 3-1 are based on 1996 gas flare rates and a conser vative gas analysis from that year and post-project emission estimates ar e based on the 2005 emi ssion inventory, updated by gas analysis data from 2005-08. The post-project emissions presented in Table 3-1 reflect the updated estimates from 2005-08 gas analyses data.

As clarified in the EPA Region IX comment lett er of November 8, 2006, post-project PTE is for the period following the dismantling of the gas pl ant, but prior to the imposition of the Consent Decree limits. Therefore, the post-project PTE emissions provided are based on 2003 flare emissions data multiplied by a PTE factor of 1.2 since the annual flare rate in 2003 was the highest of the five year period 2001-2005. Upda ted post-project PTE emissions based on more recent gas analyses from late 2005 through 2008 and the natural gas flow rate from 2003 multiplied by 1.2 are also provided. These post -project PTE determinations were made in accordance with the methodology outlined in 40 CFR § 63.760(a)(1)(i)(B) (E&P MACT) and past Texas Commission on Environmental Quality (TCEQ) guidance on PTE calculations for oil & gas operations. Applicable calculation me thodology with input data used to estimate emissions are presented in Appendix B.

The gas flow rates to the flare used for the emission estimates are 1,145.96 MMscf in 1996 (for both actual and PTE emissions), 727.704 in 2005 (rounded off to 730.0 MMSCF) for postproject actual emissions, and 1,070.366 MMscf for post-project PTE emissions. Because the flare is only used for emergency relief and to c ontrol dehydrator still vent emissions, the daily rates vary.

### 3-2 Table 3-1 Pre-Project and Post-Project Actual and PTE Emissions

Criteria Pollutant Pre-Project Actual Emissions (tpy) Pre-Project PTE 1 

### (tpy) Post-Project Actual Emissions (tpy) Post-Project PTE 2 

### (tpy) CO 159.2 159.2 82.5 135.1 NO x 

### 29.3 29.3 15.2 24.8 VOC 183.6 183.6 91.7 151.8 SO 2 

### 138.1 138.1 30.1 44.2 Lead 0.00021 0.00021 0.000109 0.000179 PM 10 

### 3.2 3.2 1.7 2.7 PM 2.5 

### 3.2 3.2 1.7 2.7

1 Pre-project PTE is equivalent to 1996 actual emission estimates.

2 Post-project PTE is estimated by identifying the maximum annual gas flow rate from the most recent five-year

period with available data (i.e., 2001 – 2005) and multiplying by a contingency factor of 1.2 to provide a worstcase post-project PTE estimate. The maxi mum gas flow year of 2003 was select ed as the basis for this estimate. The maximum BTU content from 2005-08 gas analyses data (682.4 BTU/SCF) was assumed for emission estimates.



### 3.1 CRITERIA POLLUTANTS

Table 3-2 presents a summary of criteria pollutant emission limits for the Main Flare as listed in Paragraph 9.a of Exxon Mobil’s Consent Decree. Due to the higher BTU content occurring since issuance of the Consent Order, Reso lute is requesting revised emission limits corresponding to the last column of Table 3-1.

Table 3-2 Main Flare Criteria Pollutant Emission Limits 1



### Pollutant tons/year 2



### SO 2 

### 60

CO 73

NOx 13.4

VOC 95.4

1. As listed in Paragraph 9.a of Consent Decree (DOJ Case No. 90-5- 2-1-2237) 2. Cumulative 365-day rolling average.

### 4-1 4.0 BEST AVAILABLE CONTRO L TECHNOLOGY ANALYSIS

The 1977 Clean Air Act Amendments establishe d revised conditions for the approval of preconstruction permit applications under the PSD Program. One of these requirements is that Best Available Control Technology (BACT) be installed for a ll pollutants regu lated under the Act emitted in significant amounts from new major sources or modifications. BACT is defined

as an emission limitation based on the maximu m degree of pollutant re duction determined on a case-by-case basis considering technical, ec onomic, energy, and environmental factors. Additionally, a BACT limitation cannot be less stri ngent than emissions limits established by an applicable New Source Performanc e Standard (NSPS). For this sp ecific case, a BACT analysis will be performed for VOC, CO, NO x 

### , and SO 2 

### from the Main Flare as required by ExxonMobil’s Consent Decree (DOJ Case No. 90-5- 2-1-2237). Current and future operation of

the Main Flare will not otherwise trigger PSD review. The Main Fl are is used to incinerate the residual hydrocarbons and su lfur in the injection gas stream during times when injection is not possible, thus, controlling VOC and H 2 

### S emissions.

EPA has specified use of a “top-down” approach to BACT determinations, in order to bring consistency to the BACT process. The step s of a Top-Down BACT determination are:

1. Identify all available control options;

2. Evaluate and eliminate those options that are technically infeasible;

3. Rank remaining control alternativ es by control effectiveness;

4. Evaluate feasibility of each control option and combinations of control options on the basis of energy, environmental and economic factors;

5. The most stringent control option or combina tion of options found to be feasible on the basis of technical, energy, e nvironmental and economic fact ors is selected as BACT.

The first step, to determine all control options for the pollutant in question and emission unit(s) under review, requires research to determine what available control opti ons exist. The EPA

maintains a “RACT/BACT/LAER” clearinghouse of historical BA CT determinations, known as the “RBLC” database, which can be very useful in gathering an initial list of control options. Other resources may be used as available to comp lete the list. Following a technical feasibility assessment for all options, those found to be tec hnically feasible are ev aluated and ranked on the

### 4-2 basis of control effectivene ss (encompassing percent removal, amount of emission reduction, energy impacts, environmental impacts, and economi c factors). When inve stigating each control option in order of effectiveness, it is important to identify individual controls that can be combined on the basis of technical feasibility. These combinations may result in control alternatives that are more effective than the sepa rate individual control op tions. As the final step, the most effective control option or combination of options that has not been eliminated is

selected as BACT.

EPA Region IX has also requested the Top-Down BACT analysis to consider ope rating options that would reduce the need to flare. Specifi c options to be analyzed include improving the efficiency, reliability and/or capacity of the ga s compressors and measures designed to reduce flaring frequency and the quantity of gas flared. Thus, the options evalua ted in this Top-Down analysis are:

1. Increasing the reliability and efficiency of the existing Dresser HOS-6 compressor 2. Installation of a flare gas recovery unit (FGRU) that w ould capture most of the gas potentially flared for further processing

The Top-Down BACT analysis presented below cons iders control alternatives for the flare itself and alternative operating options designed to minimize the need for flaring consisting of modifications to the HOS-6 compressor or installation of a FGRU.

4.1 ALTERNATIVE CONTROLS FOR FLARE

4.1.1 Volatile Organic Compounds (VOCs)

The purpose of a flare system is to control pr ocess equipment operation through the safe and effective disposal of gases and liquids. Flare systems are considered as an emission control device for VOCs, since combustion through a flaring system prevents the release of hydrocarbons to the atmosphere. When combusti on is not complete, flares will emit VOCs in the form of unburned hydrocarbons. The EPA addr essed this issue thr ough regulations in the New Source Performance Standard’s (NSPS) Gene ral Control Device Requirements at 40 CFR § 60.18 and in the Control Device Requirement s for the National Emission Standards for

### 4-3 Hazardous Air Pollutants (NESHAP) regulations at 40 CFR § 63.11. These requirements establish specifications on visible emissions, cont inuous presence of a flame, exit velocities, fuel heating value, and monitoring for flare system s applicable to any NSPS, 40 CFR Part 61 NESHAP, or 40 CFR Part 63 NE SHAP, with the intent to ensure 98 percent control (hydrocarbon destruction) efficiency for applicab le flares. This objective was based on tests confirming 98 percent control efficiencies for flares combusting organic emissions. Additionally, flare manufacturer s such as the John Zink Company LLC established that a “properly designed and operated” fl are burner will have a combustion efficiency of more than 98 percent. Flares not subject to an NSPS or NESHAPs are not required to meet these specifications.

In order to achieve the visi ble emission requirements of 40 CFR § 60.18 and 40 CFR § 63.11, “smokeless” flare systems are designed with some type of external mome ntum force, such as steam, air, water spray, natural gas, or a specialized high ve locity vortex design. An external momentum force provides for more comple te combustion by improving the fuel flow momentum, which allows a sufficient amount of combustion air to be educted into the combustion zone just outside the flare burner. Hi gh-pressure flares (5 to 10 psig or more) might not require a supplemental external momentum design in order to achieve smokeless combustion. However, many flare systems require some type of supplemental assist in order to achieve smokeless operation and 98 pe rcent control efficiency. Steam injection is common, as it

can add sufficient momentum and aid the chemistr y of the combustion proc ess. Low-pressure air can be used as an assist medium in loca tions where steam, water, or gas is not readily available or where cold temperatures present freezing issues. In this case, a blower is utilized to inject approximately 15 to 50 percent of the stoichiometric air requirement into the flame, providing adequate momentum to achieve sm okeless and complete combustion. Air-assist design is often used in remote locations. Gas-as sist with natural gas can provide an additional benefit by increasing the heating valu e to the fuel stream, in situations where the waste gas to be combusted does not have a sufficient heating valu e for safe combustion. Available literature suggests that each technology option for suppleme ntal external momentum provides similar

additional control to VOC emissi ons from flare systems.

Table 4-1 presents a summary of recent BACT determinations from the EPA’s RBLC database

for flare VOC emissions. The table shows that se ven of the twelve RBLC determinations did not

### 4-4 list any control technology for VOCs, although four of those seven de terminations noted flares as

the control device for VOC emissions. Three of th e entries which noted flares as a VOC control device went on to state the flare would have 98% control efficiency, and one entry also stated the flare would be designed and opera ted to meet 40 CFR § 60.18 specifications. Four of the twelve entries noted the use of “gas-a ssisted” smokeless flare systems as the VOC control technology. (Note that it is not clear in the RBLC if “gas-assisted” refers to the use of air or natural gas as the source of external momentum.) One of the twelve determinations noted “good combustion practices” as the control tec hnology. For those seven determinations where no control technology was specified, including those noting th e flare system as the control device for VOCs, it cannot be determined if those flare syst ems are designed and operated with any type of supplemental external momentum technology such as steam, air, or gas-assist . It is logical to conclude that some of these systems might have an “assisted” design, partic ularly in the case of the refinery flares, if the compliance with th e provisions of 40 CFR § 60.18 or 40 CFR § 63.11 is required.

Based on review of Table 4-1 and knowledge of controls used to reduce VOC emissions from flare systems, the possible VOC contro l options for the Main Flare are:

• No control/good combustion practices;

• Meet requirements of 40 CFR § 60.18 and/or 40 CFR § 63.11 for flare systems; and

• Supplemental external momentum design - steam, air, or ga s-assist technology.

Some overlap exists between the second and thir d options, because as e xplained previously, the visible emission requirements of 40 CFR § 60.1 8 and 40 CFR § 63.11 are frequently met by the use of a supplemental external momentum design, such as steam, air, or gas technology. Therefore, in some cases, compliance with th e requirements of the NSPS or NESHAP control device regulations can only occur by utilizing a supplemental external momentum design such as steam, air, or gas-assist technology.

Of the options listed above, steam-assisted t echnology is immediately determined to be infeasible. The McElmo Creek Gas Compression F acility is located in a remote area, where steam is not readily available. Therefore, th e only feasible supplemen tal external momentum designs are air and gas-a ssist technologies.

### 4-5 The McElmo Creek Gas Compression Facility’s Ma in Flare has not been previously viewed as subject to the requirements at 40 CFR § 60.1 8 or 40 CFR § 63.11, because its use was not specifically for compliance with a provision of a NSPS or NESHAP . However, Paragraph 11(b) of the Consent Decree with the EPA (DOJ Case No. 90-5-2-1-2237) states that “...[t]hereafter, Mobil shall operate and mainta in the Main Flare in complia nce with 40 CF R § 60.18(c)(1), (c)(2), (c)(3)(ii), (c)(5), (d), (e), (f)(1) through (f)(4), and (f)(6). Additi onally, Paragraph 11(b) of

the Consent Decree states that “W ithin three hundred sixty-five (365) days from the Effective Date, Mobil shall install an automatic air-assisted flare system on the Main Flare, pursuant to the provisions of 40 CFR §60.18(c)(5) and (f)(6). Therefore, Cons ent Decree conditions requiring compliance with NSPS requirements (typical star ting point for BACT), supplemented by one of the three supplemental ex ternal momentum technologies, repr esents the most stringent BACT currently implemented. On this basis, furthe r analysis of employing a gas-assist technology rather than air-assist is unnecessary, since ther e would be no additiona l environmental benefit from using gas-assist. VOC BACT is proposed to be the combination of air-assist technology and complying with the flare specifications of the General Control Device Requirements at 40 CFR § 60.18 as specified in the Consent Decree.

4.1.2 Carbon Monoxide (CO)

Carbon monoxide (CO) from flar e systems is formed in the sa me manner as any combustion process – through incomplete combustion. VOC em issions from flare systems also originate from incomplete combustion. Therefore, control options to address CO emissions from flares

will be the same as those for VOC emissions.

Table 4-2 presents a summary of recent BACT determinations from the EPA’s RBLC database

for flare CO emissions. Nine of the sixteen de terminations do not cite a specific CO control technology. It is uncertain how many of the flares represented by these determinations are designed and operated with any type of supplemental external momentum technology such as steam, air, or gas-assist technology; however, it is reasonable to conc lude that some of the listed flares, particularly those located at petroleum refineries, utiliz e an assist technology in order to meet NSPS and NESHAP requirements. Four of th e sixteen determinations note the use of “gasassist” smokeless technology (note th at it is not clear in the RBLC if “gas-assisted” refers to the use of air or natural gas as the source of external momentum ). Two entries cite “proper

### 4-6 operation and maintenance,” and one entry cites “good combustion practices ” as the CO control technology, with no further detail provided.

Based on review of Table 4-2, and typical flar e system operations, BACT options for CO are

considered to be identical as those for VOC. Therefore, CO BACT is proposed to be the

combination of air-assist techno logy and the requirement to meet the flare specifications under

the General Control Device Re quirements at 40 CFR § 60.18.

4.1.3 Nitrogen Oxides (NO x 

### )

There are three principal forms of NO x 

### , designated as “thermal” NO x 

### , “prompt NO x 

### ,” and “fuel”

NO x 

### . Thermal NO x 

### formation is the result of oxidation of atmospheric nitrogen contained in the inlet gas in the high-temperature, post-flame re gion of the combustion zone. The major factors influencing thermal NO x 

### formation are temperature, concentrat ions of nitrogen and oxygen in the inlet air, and residence time within the combustion zone. Prompt NO x 

### is formed through relatively fast reaction between nitrogen, oxygen, and hydrocarbon radicals and is an important mechanism in lower temperature combustion processes. Fuel NO X 

### is formed by the oxidation of fuel-bound nitrogen. It is not a concern for high- quality gaseous fuels such as natural gas or propane, because these fuels normally have no organically-bound nitrogen. Fuel NO x 

### is a concern when burning oil, coal, or waste fuels.

Generally, several options exist to reduce NO x 

### emissions from combustion processes, such as pre-treating the fuel or switching fu els and/or oxidizers to prevent NO x 

### formation, modifying the combustion process or equipment to lower NO x 

### formation, and post-treatment end-of-pipe technologies to remove NO x 

### . These options are listed below:

Pre-Treatment Combustion Modification Post-Treatment

• Fuel switching • Air Preheat Reduction • SCR

• Fuel additives • Burners Out-of-Service • SNCR

• Oxidizer switching • Low NOx burner

Post-treatment, end-of-pipe options are not technically feasible for flare systems, due to the inherent design of flaring and th e fact that literally, no end-of-p ipe exists after the combustion

### 4-7 zone. Combustion modification options have limite d technical feasibility for flare systems, as well. Reducing the amount of air preheat and ta king burners out of serv ice are options intended for process heaters and boilers, where the combusti on air is heated for more efficiency and where multiple burners exist. Low NO x 

### burners incorporate concepts such as lowering excess air, fuel staging, and gas recirculation, which can be succ essfully implemented with process heaters and boilers. However, flare burner de sign differs substantially from process heater and boiler burner design, because the primary objective of flare bur ner design is to achieve safe and complete combustion of unwanted hydrocarbons, sometimes in emergency situations, and often in unpredictable volumes, flowrate s, and temperatures. E ssentially, the best low-NO x 

### burner for a flare is a well-designed one, prop erly sized and constructed for a specific flare’s conditions. Thus, the only technically feasible options for NO x 

### control from the Main Flare fall within the pre-treatment category; however, few options in this category are technically feasible.

Fuel additives, intended to change the chem istry of the combustion process, operate under specific temperature conditions and stable operati ons, neither of which ar e possible with flare systems. Oxidizer switching, where pure oxygen is used for combustion rath er than air, is not widely used in the hydrocarbon, petrochemical, a nd power generation industries due to the cost and energy requirements of producing pure oxygen. Fuel switching from fuels with higher fuel-bound nitrogen contents to those with lower fu el-bound nitrogen contents is a possible option for reducing NO x 

### from flare systems, but only in specif ic cases where the fuel to the flare can be controlled and predicted.

Table 4-3 presents a summary of recent BACT determinations from the EPA’s RBLC database

for flare NO x 

### emissions. Eight of the twelve determinations do not cite a specific NO x 

### control technology. Two of the twelve determinations note “proper operation and maintenance” as the control technology, one notes a limitation on fuel type (use of natural gas only) and one notes the flare will be operated in accordance with 40 CF R § 60.18 General Control Device requirements. Based on review of Table 4-3, and th e previous discussion of possible NO x 

### control technologies for combustion processes, the list of possible NO x 

### control options for the Main Flare are:

• No control/good combustion practices;

• Meet requirements of 40 CFR § 60.18 and/or 40 CFR § 63.11 for flare systems; and

• Fuel switching.

### 4-8 Of these options, fuel switching has been determin ed to be technically infeasible for the Main

Flare. Fuel is sent to the Main Flare through various pressure -relief piping or compressor bypass piping, as a result of emergency or maintenan ce situations, and also continuously from the dehydration reboiler. This fuel stream to the Ma in Flare cannot be switc hed without inherently changing the compressor plant’s purpose and design. Furthermore, the fuel to the Main Flare consists of light hydrocarbons (methane, ethane, propane) and car bon dioxide, with very little fuel-bound nitrogen content.

Since the Consent Decree requires the site operato r to “operate and maintain the Main Flare in compliance with 40 CFR § 60.18(c)(1), (c)(2), (c)(3)(ii ), (c)(5), (d), (e), (f )(1) through (f)(4), and (f)(6)” following installation of an air-assist technology, BACT for NOx is proposed as meeting the General Control Device requirements of 40 CFR § 60.18 for flare systems. Compliance with these requirements also guarantees that good combustion practices are being followed.

4.1.4 Sulfur Dioxide (SO 2 

### )

Sulfur dioxide emissions from flare systems depe nd on the amount of sulfur in the fuel stream. Typically, sulfur dioxide from combustion proce sses can be controlled through limiting the fuel type or sulfur content, or th rough end-of-pipe control technology. As discussed in section 4.3, end-of-pipe control technol ogies are not feasible for flare syst ems. Therefore, the primary means of controlling SO 2 

### emissions from flare systems is to limit the fuel type or sulfur content, where possible.

Table 4-4 presents a summary of recent BACT determinations from the EPA’s RBLC database

for flare SO 2 

### emissions. Ten of the sixteen determin ations note some type of fuel sulfur

limitation as the control t echnology. Five entries do not list any type of SO 2 

### control technology, and one entry contains a reference to contin uous pilot ignition, flame monitors, and other specifications that can be found in the 40 CF R § 60.18 flare requiremen ts. Following this review, the SO 2 

### control options for the Main Flare are determined to be:

• No control/good combustion practices;

• Limit fuel type; and

• Limit sulfur content.

### 4-9 Limiting the fuel type has been determined to be a technically infeasible option for the Main

Flare. As discussed in Section 4.3 for NOx, the fuel sent to the Main Flare is a combination of the process gas which is compressed for re-injec tion and the vent stream from the dehydration

reboiler. This fuel stream cannot be switched to a different type without inheren tly changing the compressor plant’s purpose and design.

Additionally, limiting the fuel’s sulfur content has been determined to be technically infeasible. The compressor plant is designed and operated to co mpress gas and re-inject it into the field. The gas directed to the compressor plant is not pro cessed for sale or sold to outside customers. Its average hydrogen sulfide (H 2 

### S) content is 400-500 ppm , with the maximum H 2 

### S content potentially higher, depending on the quality of pr oduct from the field. Limiting the sulfur or hydrogen sulfide content in the gas directed to the Main Flare coul d result in an inherent change to the compressor plant’s purpose an d design, because the gas to the Main Flare is a combination of process gas and dehydrator vent gas, and because the plant’s design does not call for any sweetening process due to the fact th at it is re-injected, and not sold.

The only remaining technically feasible optio n is no control/good combustion practices. Therefore, BACT for SO 2 

### is proposed as good combustion practices, which will be achieved through compliance with 40 CFR § 60.18 flare operational requirements.

4.2 COMPRESSOR ENGINE MODIFICATIONS

4.2.1 Past Flaring Due to Compressor Downtime

The majority of the flaring at McElmo Creek Ga s Compression Facility is a result of downtime associated with the HOS-6 compressor. This unit is a 4-stage, 6-cylinder Dresser HOS model compressor, which is driven by an electric motor.

HOS-6 compressor reliability is influenced by th e interaction of the ga s composition and process requirements at McElmo Creek. The gas is pr imarily composed of carbon dioxide and has a tendency to liquefy at relative low temperatures . The gas pressure between the 3rd and 4th stages of compression is approximately 1000 psi. The gas at this pr essure liquefies at approximately 85 °F. Additionally, the discharge pr essure is above the critical pressure of the

### 4-10 gas. Therefore, the process st ream actually leaves the compre ssor and can simultaneously have the properties of a liquid and a gas. It is when the gas beha ves as a liquid that compressor damage can occur. This mixed gas stream allo ws for the potential of liquid drop-out throughout the compression process.

In an effort to reduce the potential for damage on the 4th stage of the compressor, the field operations group attempts to maintain the sucti on temperature of the 4th stage near 100° F. However, the large temperature swings that can occur in the McElmo Gas Compression Facility area, especially in the winter months, make this difficult. Some of the issues are:

• No automatic controls on the coolers

• Gas separation between stages located remotely from the compressor

• Piping between the separation equipment and the compressor having multiple elevation changes, which increase the poten tial for liquid accumulation in the lines.

The compressor has had downtime associated with 2nd stage failures due to liquids entering the cylinder. The implemented solution was to remove the liquid traps between the separation and compression equipment. This eliminated liquid collection and slugging, thereby reducing downtime events significantly.

4.2.2 Options to Improve Reliability of HOS-6 Compressor Engine Operations

A Top-Down analysis of options to increase reliability of compressor engine operation is presented below. Cost effectiveness based on annual emissions reduction of each pollutant is estimated for each option to evaluate economic feasibility. Cost estimation methodology is

based on the EPA Cost Control Manual. E xxonMobil experience with capital costs and maintenance labor is cited, but actual cost effectiveness estimates are based on the EPA costing factors. Implementing these options is assume d to achieve a minimum decrease of 75% and up to a maximum of 95% of base emissions for e ach pollutant. The maximum of 95% is based upon industry experience in which compressor downtime of 5% annually is considered acceptable. As discussed below, options for in creasing the reliability of compressor engine operation are changing the compression process and replacing the compressor engines.

### 4-11 Change Compression Process

Reducing the discharge pressure of the recipro cating compression, cooling the gas stream to liquefy it, and utilizing pumps to reach the requ ired pipeline pressure could provide increased reliability and minimize potential compression failu res at the McElmo Gas Compression Facility. However, this would require new refrigeratio n equipment, new pumps, and, at a minimum, restaging of the existing compression. Further co rrective actions would also be necessary, as described below, if the existing HOS-6 compressor was used.

The estimated equipment cost for this correc tive action would be $12,0 00,000, at a minimum, if the HOS-6 compressor was reconfigured for this process. Based on the cost-effectiveness analyses in Tables 4-5a and b, this method is consider ed economically infeasible. To achieve a 95% reduction in annual emissions of each pollu tant, the cost effectiveness is a minimum of $36,687 per ton of VOC removal.

Replace the HOS-6 Compressor

This option would replace the HOS -6 unit with one or more reciprocating compressors. The basic process would not change. Replacing the existing compre ssor may reduce the potential for liquid retention by utilizing differe nt piping configurations. Howe ver, problems inherent with the process would still remain.

The equipment cost for this corrective action would be approximately $10,000,000, at a

minimum. Based on the cost-effectiveness anal yses in Tables 4-6a and b, this method is considered economically infeasible. To ach ieve the maximum of 95% reduction in annual emissions of each pollutant, the cost effectiv eness is a minimum of $30,665 per ton of VOC removal. In addition, compression process issues contributing to potential flaring would remain.

4.2.3 Other Compression Changes

The following potential changes to compression operati ons were also considered, but their effect on reducing the frequency or duration of flar ing is uncertain and may be minimal since documented studies of the results from impl ementing these changes are not available.

### 4-12 Relocate the HOS-6 separation equipment

By moving the HOS-6 separation equipment closer to the compression e quipment, the potential for liquid forming in the intermediate piping an d entering the compressor would be reduced. A potential for liquid entering the compressor equipm ent would still remain because of the size of the separation equipment required on the HOS-6 compressor. A dditionally, relo cation of the separation equipment would not remove the inhe rent process issues and there would be no assurance of flaring freque ncy and duration reductions.

Reconfigure piping

Reconfiguring the piping between the separation and compression equipment, similar to replacing the compressor or relo cating the separation equipment, would reduce the potential for liquids to enter the compression equipment by removing liquid traps. The potential for downtime occurrences would still remain, however , and there would be no assurance of flaring frequency and duration reductions.

Insulate and heat-trace the piping

By insulating and heat-tracing th e piping between the separation a nd compression equipment, the probability of the gas cooling and liquids formi ng would be reduced. The potential for liquids entering the compression equipment would still remain and there would be no assurance of flaring frequency and duration reductions.

4.3 FLARE GAS RECOVERY SYSTEMS

Another method of reducing flaring emissions is to recover gas that woul d otherwise be flared and redirect for further processing in the exis ting gas compression facility. Description of a commercially available flare gas recovery unit (FGRU) is provided below to illustrate its operation.

• The Flare Gas Recovery Unit (FGRU) initially withdraws gas from the flare header upstream of the liquid seal drum and rec overs gas normally combusted by the flare;

### 4-13 • To prevent ambient air from being drawn in to the flare system or FGRU, the FGRU operates with a slight positive pressure upstream of the liquid seal drum;

• As the volume of gas increases within the FGRU , the pressure exerted in the flare header will increase until equaling the back-pressure cr eated by the liquid seal drum. Any gas in excess of the back-pressure will be flared;

• As long as the pressure of the collected gas remains below the liquid seal drum backpressure, gas is diverted back to th e suction header by staging compressors;

• The staging compressors typically use liquid ring compressor technol ogy; rotary screw, reciprocating sliding vane or rotary -lobed compressors can also be used;

• The recovered gases and some of the sealin g liquid combine inside the compressor and flow into a separator vessel to separate liquids and gases;

• The compressor sealing liquid from the separator goes through a heat exchanger and returns to the compressor;

• Compressed gas from the separator is then se nt by pipeline to its sales destination.

Various vendors of FGRUs use different methods for achieving the sealed system necessary to prevent recovered gas from simply flowing past the flare header and being flared into the atmosphere. However, the degree of difficulty in installing and operating th e variety of available FGRU systems is similar both in terms of costs and technical considerations.

Cost effective use of FGRUs are typically achiev ed by large oil and ga s production facilities where the volume of recovered gas becomes additional sales gas and its revenue from this can largely offset initial FGRU costs and future opera ting costs within a few years. Thus, facilities that have successfully used FGRUs and have f ound them to be both technically and financially feasible are large production faci lities. The amount of recovered flared gas at th ese facilities represents a significant revenue stream. The Main Flare at the McElmo Gas Compression Facility is used intermittently and the additional volume of gas that would be recovered as sales gas would minimally offset the substantial ec onomic costs associated with installing and operating the FGRU system.

The equipment cost associated with a t ypical FGRU is approximately $1,300,000. Since additional compressors are required and the cost a ssociated with their installation are similar to

### 4-14 those cited for the replacement of existing compressors in Section 4.2.2 (i.e., $10,000,000), the total equipment cost is estimated as $11,300,000. Based on the cost-effectiveness analyses in Tables 4-7a and b, this method is considered economically infeasible. To achieve the 75% reduction in annual emissions of each pollutant, the cost effectiveness is a minimum of $43,801 per ton of VOC removal. In addition, efficient use of a FGRU for an application of this small

size is uncertain. This uncerta inty in demonstrated efficien cy does not support the use of a control efficiency higher than 75%.

4.4 OPERATION & MAINTENANCE (O&M) PLAN

Since the above options are considered impr actical because of cost-ineffectiveness or uncertainty, the existing facility and equipment must be operated and maintained in such a manner to reduce compressor downtime and thereby, keep flaring to a minimum. This prudent operation and maintenance is conducted in accordance with Paragraphs 9.a, 10, and 11 and in accordance with Appendix B (the "O&M Plan") of the Consent Decree. This includes constant monitoring, inspecting and performing mainte nance on the compressors and associated equipment in accordance with the Life Cycle Ma intenance Plan in Appendix B of the Consent Decree, maintaining a supply of designated spare parts for th e compressors and associated equipment, and training all operators on the De cree requirements and the "O&M Plan." This practice, therefore, constitutes BACT for reduc ing the occurrence of flaring at the Facility.

Resolute has already taken measures to further reduce compressor downtime, thereby minimizing flaring, by installing a fifth electric-powered compressor/engine at the McElmo facility in 2007. This compre ssor is a 2,500 horsepower, f our-stage, five cylinder unit (designated as C5) with tota l installed costs of $5,459,950. This significant expenditure to further increase compressor reliability is indicative of Resolute’s intent to minimize flaring.Page 1 of 8BACT/LAER Clearinghouse Database SummaryDeterminations 1995 – 2005Industrial Flares (RBLC Report 8/4/05)Table 4-1. BACT Determinations for Flare VOC EmissionsCompany Location EmissionSourceThroughput(Size)Pollutant Emission Limit Control Technology BACT, LAER, orOtherPermit DateExxon MobilSalt Creek Gas PlantKent County,TX2 Flares Not provided VOC 42.82 lb/hr, each156.31 tpy,combinedNone listed –Notes flare as VOC controldevice,with 98% efficiencyBACT 1/31/2003Conoco, Inc.Ponca City RefineryKay County,OK1 Flare 0.20 lb/MMbtu –no further detailprovidedVOC 0.14 lb/MMbtu Good combustion practice BACT 7/1/2002Valero Refining Co.Corpus ChristiRefineryNueces County,TXMain Flare –2 groups ofequipmentvents to flareNot provided VOC 226 lb/hr39.6 tpy, and4,013 lb/hr1,544 tpy(2 sets of limits)None listed. Notes flare as VOCcontrol device, with 98%efficiency.Process notes indicate flare will bedesigned & operated per 40 CFR §60.18.BACT 6/11/2002Duke Energy FieldServices - MindenWebster Parish,LA1 Flare Not provided VOC 2.82 lb/hr8.73 tpyNone listed “other case by case”– this action was aminor modificationonly1/24/2002Orion Refining Co.St. CharlesParish, LA2 Flares 60,700,000 Btu/hr,eachVOC 25.4 lb/hr, each16.7 tpy, eachNone listed. Notes flare as VOCcontrol device, with 98% controlefficiency.BACT 1/10/2002Flint Hills ResourcesLPWest RefineryNueces, TX Flares Not provided VOC 4,036.26 lb/hr2,982.09 tpy,Both “initial” capsNone listed. “other case-by-case” 10/5/2001Trifinery PetroleumServiceTrigeant CorpusChristiNueces, TX 1 Flare Not provided VOC 12.74 lb/hr55.79 tpyNone listed. Notes flare as VOCcontrol device.“other case-by-case” 8/7/2000Citgo Refining &Chemicals Co LPCorpus ChristiRefinery – WestPlantNueces, TX 1 Flare (HP) 80,000 scf/day VOC None listed “Gas- Assist” smokelesstechnology“other case-by-case” 10/15/1999Page 2 of 8BACT/LAER Clearinghouse Database SummaryDeterminations 1995 – 2005Industrial Flares (RBLC Report 8/4/05)Company Location EmissionSourceThroughput(Size)Pollutant Emission Limit Control Technology BACT, LAER, orOtherPermit DateCitgo Refining &Chemicals Co LPCorpus ChristiRefinery – WestPlantNueces, TX 1 Flare (LP) 20,000 scf/day NG430,000 scf/dayproduced gasVOC None listed “Gas- Assist” smokelesstechnology“other case-by-case” 10/15/1999BP Exploration Inc.NorthstarDevelopment FacilityAK 1 Flare (HP) 660,000,000 scfd VOC None Gas-assist smokeless flaretechnology“other case by case” 2/5/1999BP Exploration Inc.NorthstarDevelopment FacilityAK 1 Flare (LP)Natural andProducedGas18,022,000 scfd VOC None Gas-assist smokeless flaretechnology“other case by case” 2/5/1999Mobil Exploration &Producing US, Inc.Salt Creek Gas PlantKent County,TXProcessEmergencyFlareNot provided VOC 0.01 lb/hr0.01 tpyNone listed “other case by case” 10/13/1998Page 3 of 8BACT/LAER Clearinghouse Database SummaryDeterminations 1995 – 2005Industrial Flares (RBLC Report 8/4/05)Table 4-2. BACT Determinations for Flare CO EmissionsCompany Location EmissionSourceThroughput(Size)Pollutant Emission Limit Control Technology BACT or LAER Permit DateExxon MobilSalt Creek Gas PlantKent County,TX2 Flares Not provided CO 37.2 lb/hr, each135.8 tpy, combinedNone listed BACT 1/31/2003Conoco, Inc.Ponca City RefineryKay County,OK1 Flare 0.20 lb/MMbtu –no further detailprovidedCO 0.37 lb/MMbtu Good combustion practice BACT 7/1/2002Valero Refining Co.Corpus ChristiRefineryNueces County,TXMain Flare Not provided CO 472 lb/hr90.5 tpyNone listed. BACT 6/11/2002Duke Energy FieldServices - MindenWebster Parish,LA1 Flare Not provided CO 0.26 lb/hr1.14 tpyNone listed “other case by case”– this action was aminor modificationonly1/24/2002Orion Refining Co.St. CharlesParish, LA2 Flares 60,700,000 Btu/hr,eachCO 149 lb/hr, each98.3 tpy, eachNone listed. BACT 1/10/2002Flint Hills ResourcesLPWest RefineryNueces, TX Flares Not provided CO 901.5 lb/hr2,657.98 tpy,Both “initial” capsNone listed. “other case-by-case” 10/5/2001Trifinery PetroleumServiceTrigeant CorpusChristiNueces, TX 1 Flare Not provided CO 16.3 lb/hr71.36 tpyNone listed. “other case-by-case” 8/7/2000Tesoro Alaska CoKenai RefineryAK 1 Flare 1,000,000 Btu/hr CO 0.04 lb/MMBtu None listed. “other case-by-case” 3/21/2000Tesoro Alaska CoKenai RefineryAK 1 Flare (HP) 261,000,000 scfd CO 0.37 lb/MMBtu Proper Operation & Maintenance “other case-by-case” 3/21/2000Tesoro Alaska CoKenai RefineryAK 1 Flare (LP) 212,000,000 scfd CO 0.37 lb/MMBtu Proper Operation & Maintenance “other case-by-case” 3/21/2000Citgo Refining &Chemicals Co LPCorpus ChristiNueces, TX 1 Flare (HP) 80,000 scf/day CONone listed “Gas- Assist” smokelesstechnology“other case-by-case” 10/15/1999Page 4 of 8BACT/LAER Clearinghouse Database SummaryDeterminations 1995 – 2005Industrial Flares (RBLC Report 8/4/05)Company Location EmissionSourceThroughput(Size)Pollutant Emission Limit Control Technology BACT or LAER Permit DateRefinery – WestPlantCitgo Refining &Chemicals Co LPCorpus ChristiRefinery – WestPlantNueces, TX 1 Flare (LP) 20,000 scf/day NG430,000 scf/dayproduced gasCO None listed “Gas- Assist” smokelesstechnology“other case-by-case” 10/15/1999BP Exploration Inc.NorthstarDevelopment FacilityAK 1 Flare (HP) 660,000,000 scfd CONone Gas-assist smokeless flaretechnology“other case by case” 2/5/1999BP Exploration Inc.NorthstarDevelopment FacilityAK 1 Flare (LP) 18,022,000 scfd CONone Gas-assist smokeless flaretechnology“other case by case” 2/5/1999Mobil Exploration &Producing US, Inc.Salt Creek Gas PlantKent County,TX1 Flare Not provided CO 1.1 lb/hr4.8 tpyNone listed “other case by case” 10/13/1998Equistar Chemicals,LPNueces, TX 2 Flares Not provided CO 0.05 lb/hr, each0.23 tpy, eachNone listed. BACT 10/8/1998Page 5 of 8BACT/LAER Clearinghouse Database SummaryDeterminations 1995 – 2005Industrial Flares (RBLC Report 8/4/05)Table 4-3. BACT Determinations for Flare NOxEmissionsCompany Location EmissionSourceThroughput(Size)Pollutant Emission Limit Control Technology BACT or LAER Permit DateExxon MobilSalt Creek Gas PlantKent County,TX2 Flares Not provided NOx 4.37 lb/hr, each15.85 tpy, combinedNone listed BACT 1/31/2003Conoco, Inc.Ponca City RefineryKay County,OK1 Flare 0.20 lb/MMbtu –no further detailprovidedNOx 0.068 lb/MMbtu Limit fuel to pipeline-grade naturalgasBACT 7/1/2002Valero Refining Co.Corpus ChristiRefineryNueces County,TXMain Flare Not provided NOx 75.8 lb/hr18.8 tpyNone listed. BACT 6/11/2002Orion Refining Co.St. CharlesParish, LA2 Flares 60,700,000 Btu/hr,eachNOx 33.6 lb/hr, each45.3 tpy, eachNone listed. BACT 1/10/2002Flint Hills ResourcesLPWest RefineryNueces, TX Flares Not provided NOx 1,409.8 lb/hr5,266.82 tpy,Both “initial” capsNone listed. “other case-by-case” 10/5/2001Trifinery PetroleumServiceTrigeant CorpusChristiNueces, TX 1 Flare Not provided NOx 3.2 lb/hr14.01 tpyNone listed. “other case-by-case” 8/7/2000Tesoro Alaska CoKenai RefineryAK 1 Flare 1,000,000 Btu/hr NOx 0.14 lb/MMBtu None listed. N/A 3/21/2000Tesoro Alaska CoKenai RefineryAK 1 Flare (HP) 261,000,000 scfd NOx 0.068 lb/MMBtu ProperOperation & Maintenance “other case-by-case” 3/21/2000Tesoro Alaska CoKenai RefineryAK 1 Flare (LP) 212,000,000 scfd NOx 0.068 lb/MMBtu ProperOperation & Maintenance “other case-by-case” 3/21/2000Conoco, Inc.Lake CharlesRefineryCalcasieuParish, LA1 Flare Not provided NOx 1.2 lb/hr5.0 tpyOperate in accordance with40 CFR § 60.18 General ControlDevice RequirementsBACT 12/22/1998Mobil Exploration &Producing US, Inc.Salt Creek Gas PlantKent County,TX1 Flare Not provided NOx 0.08 lb/hr0.4 tpyNone listed “other case by case” 10/13/1998Page 6 of 8BACT/LAER Clearinghouse Database SummaryDeterminations 1995 – 2005Industrial Flares (RBLC Report 8/4/05)Company Location EmissionSourceThroughput(Size)Pollutant Emission Limit Control Technology BACT or LAER Permit DateEquistar Chemicals,LPNueces, TX 2 Flares Not provided NOx 0.01 lb/hr0.04 tpyNone listed. “other case-by-case” 10/8/1998Page 7 of 8BACT/LAER Clearinghouse Database SummaryDeterminations 1995 – 2005Industrial Flares (RBLC Report 8/4/05)Table 4-4. BACT Determinations for Flare SO2EmissionsCompany Location EmissionSourceThroughput(Size)Pollutant Emission Limit Control Technology BACT or LAER Permit DateExxon MobilSalt Creek Gas PlantKent County,TX2 Flares Not provided SO250.48 lb/hr, each184.24 tpy,combinedNone listed “other case by case” 1/31/2003Conoco, Inc.Ponca City RefineryKay County,OK1 Flare 0.20 lb/MMbtu –no further detailprovidedSO20.0006 lb/MMbtu Limit fuel to pipeline-grade naturalgasBACT 7/1/2002Valero Refining Co.Corpus ChristiRefineryNueces County,TXMain Flare Not provided SO251.1 lb/hr12 tpyNone listed. BACT 6/11/2002Orion Refining Co.St. CharlesParish, LA2 Flares 60,700,000 Btu/hr,eachSO2133 lb/hr, each87.6 tpy, eachNone listed. BACT 1/10/2002BP Exploration(Alaska) Inc.Milne PointProduction FacilityAK 1 Flare Max rate83,000,000 scfdNominal rate340,000 scfdSO2500 ppm, 3-hraverageBurn fuel oil with no greater than0.3 wt% sulfur, andBurn natural gas with no greaterthan 100 ppmvd H2SSIP 7/13/2001Flint Hills ResourcesLPWest RefineryNueces, TX Flares Not provided SO2962.12 lb/hr118.76 tpy,Both “initial” capsNone listed. BACT 10/5/2001Trifinery PetroleumServiceTrigeant CorpusChristiNueces, TX 1 Flare Not provided SO271.48 lb/hr263.31 tpyContinuous ignition with twopilots, UV fire-eye flame monitor,KO pot & seal druml; 98% controlefficiencyBACT 8/7/2000Tesoro Alaska CoKenai RefineryAK 1 Flare 1,000,000 Btu/hr SO2500 ppm, 3-hraverageFuel sulfur content limits:0.35% sulfur in diesel,0.01% sulfur in natural gas,0.01% sulfur in LPG, and168 ppmv H2S in refinery gasBACT 3/21/2000Page 8 of 8BACT/LAER Clearinghouse Database SummaryDeterminations 1995 – 2005Industrial Flares (RBLC Report 8/4/05)Company Location EmissionSourceThroughput(Size)Pollutant Emission Limit Control Technology BACT or LAER Permit DateTesoro Alaska CoKenai RefineryAK 1 Flare (HP) 261,000,000 scfd SO2None listed Fuel sulfur content limits:0.15% sulfur in distillate, and200 ppm H2S in fuel gasBACT 3/21/2000Tesoro Alaska CoKenai RefineryAK 1 Flare (LP) 212,000,000 scfd SO2None listed Fuel sulfur content limits:0.15% sulfur in distillate, and200 ppm H2S in fuel gas“other case-by-case” 3/21/2000Citgo Refining &Chemicals Co LPCorpus ChristiRefinery – WestPlantNueces, TX 1 Flare (HP) 80,000 scf/day SO2500 ppm, 3-hraverageH2S content limited to 50 ppmv “other case-by-case” 10/15/1999Citgo Refining &Chemicals Co LPCorpus ChristiRefinery – WestPlantNueces, TX 1 Flare (LP) 20,000 scf/day NG430,000 scf/dayproduced gasSO2500 ppm, 3-hraverageFuel sulfur content limits:0.15% sulfur in fuel oil, and50 ppmv H2S in fuel gas“other case-by-case” 10/15/1999BP Exploration Inc.NorthstarDevelopment FacilityAK 1 Flare (HP) 660,000,000 scfd SO2500 ppm, 3-hraverageH2S content of the fuel shall notexceed 50 ppmv“other case by case” 2/5/1999BP Exploration Inc.NorthstarDevelopment FacilityAK 1 Flare (LP) 18,022,000 scfd SO2500 ppm, 3-hraverageH2S content of the fuel shall notexceed 50 ppmvm, andSulfur content offuel oil shall notexceed 0.15 wt%“other case by case” 2/5/1999Conoco, Inc.Lake CharlesRefineryCalcasieuParish, LA1 Flare Not provided SO20.3 lb/hr1.1 tpyNone listed “other case-by-case” 12/22/1998Mobil Exploration &Producing US, Inc.Salt Creek Gas PlantKent County,TX1 Flare Not provided SO239.74 lb/hr174.1 tpyNone listedFuel limited to pipeline qualitysweet natural gas with no morethan 5 grains sulfur/dscf“other case by case” 10/13/1998ItemExxonMobil Assumptions ExxonMobil CommentsDIRECT CAPITAL COSTS1. Purchased Equipment:A) Process ChangesBase Cost$12,000,000$12,000,000B) Instrumentation & Controls10% of Base Cost$1,200,000$1,800,000In the EM estimate, 15% is the factor used for Instrumentationbased on ExxonMobil experience instead of the EPA 10%basis. The EPA cost cost control manual states that factorsrange from 5% to 30%.C) Freight & Taxes4% Taxes; 4%Freight on 1A & 1B$1,056,000 $1,104,000Total Purchased Equipment Costs (TEC):Sum of 1A, 1B and1C$14,256,000 $14,904,0002. Installation Costs:A) Foundation & Supports8% of TEC$1,140,480 $1,192,320B) Erection and Handling14% of TEC$1,995,840 $2,086,560C) Electrical4% of TEC$570,240 $596,160D) Piping5% of TEC$712,800 $745,200E) Insulation2% of TEC$285,120 $298,080F) Painting1% of TEC$142,560 $149,040G) Site Preparation3% of TEC$427,680 $447,120Total Installation Costs (TINC):$5,274,720 $5,514,480Total Direct Capital Costs (TDCC):Sum of TEC andTINC$19,530,720 $20,418,480INDIRECT CAPITAL COSTS1. Engineering & Supervision15% of TEC$2,138,400$2,235,6002. Construction and Field Expenses5% of TEC$712,800 $745,2003. Contractor Fees10% of TEC$1,425,600 $1,490,4004. Start-up2% of TEC$285,120$447,120In the EM estimate, 3% is the factor used for Start-up basedon ExxonMobil experience instead of the EPA 2% basis.5. Performance Testing2% of TEC$285,120$447,120In the EM estimate, 3% is the factor used for Performance Testbased on ExxonMobil experience instead of the EPA 2% basis.6. Government Permitting & Fees1% of TEC$149,040In the EM estimate, 1% is added for Government Permittingand Fees based on ExxonMobil experience.EPA Cost Control ManualTABLE 4-5aMcElmo Gas Compression FacilityChange HOS-6 Compressor ProcessCapital Cost AnalysisItemExxonMobil Assumptions ExxonMobil CommentsEPA Cost Control ManualTABLE 4-5aMcElmo Gas Compression FacilityChange HOS-6 Compressor ProcessCapital Cost AnalysisTotal Indirect Capital Costs (TICC):Sum of 1, 2, 3, 4and 5$4,847,040 $5,514,480Total Direct & Indirect Capital Costs (TDICC):Sum of TDCC andTICC$24,377,760 $25,932,960Owners Cost$3,111,955In the EM estimate, 12% is added for Owner Costs based onExxonMobil experience to cover the project management teamrequired to oversee the design, construction andcommissioningcontractors.Contingency20% of TDICC$4,875,552$7,779,888In the EM estimate, 30% is the factor used for Contingencybased on ExxonMobil experience instead of the EPA 20%basis. The EPA cost control manual states that this type ofcost estimate (a "study estimate") has a +/- 30% accuracy.TOTAL CAPITAL COSTS (TCC):Sum of TDICC andContingency$29,253,312 $36,824,803ItemExxonMobil Assumptions ExxonMobil CommentsDIRECT OPERATING COSTS1. Operating Labor2 hr/shift @ $20/hr, 3shifts/day, 365 days/yr$43,800 $43,8002. Supervisory Labor 15% of Operating Labor$6,570 $6,5703. Maintenance Labor & Materials 2% of TCC$585,066$1,104,744In the EM estimate, 3% is the factor used forMaintenance Labor & Materials based on ExxonMobilexperience instead of the EPA 2% basis.Total Direct Operating Costs (TDOC):Sum of 1 - 9$635,436 $1,155,114INDIRECT OPERATING COSTS1. Overhead60% of Total Labor +Maintenance$381,262 $693,068Total Indirect Operating Costs (TIOC):$381,262 $693,068CAPITAL CHARGES COSTS1. Property Tax 1% of TCC$292,533 $368,2482. Insurance 1% of TCC$292,533 $368,2483. General Administrative 2% of TCC$585,066 $736,4964. Capital Recovery FactorCRF = 0.1061 [10% @30 yr.]$3,103,776 $3,907,112Total Capital Charges Costs (TCCC):Sum of 1, 2, 3 and 4$4,273,909 $5,380,104TOTAL ANNUALIZED OPERATING COSTS:Sum of TDOC, TIOC andTCCC$5,290,607 $7,228,28675% control of annual SO2emissions (.95 x 44.2 tpy) =42.0$125,997per ton of SO2removal75% control of annual CO emissions (.95 x 135.1 tpy) =128.3$41,222per ton of CO removal75% control of annual NOx emissions (.95 x 24.8 tpy) =23.6$224,559per ton of NOxremoval75% control of annual VOC emissions (.95 x 151.8 tpy) =144.2$36,687per ton of VOC removalEPA Cost Control ManualTABLE 4-5bMcElmo Gas Compression FacilityChange HOS-6 Compressor ProcessOperating Cost AnalysisItemExxonMobil Assumptions ExxonMobil CommentsDIRECT CAPITAL COSTS1. Purchased Equipment:A) Process ChangesBase Cost$10,000,000$10,000,000B) Instrumentation & Controls10% of Base Cost$1,000,000$1,500,000In the EM estimate, 15% is the factor used for Instrumentationbased on ExxonMobil experience instead of the EPA 10%basis. The EPA cost cost control manual states that factorsrange from 5% to 30%.C) Freight & Taxes4% Taxes; 4%Freight on 1A & 1B$880,000 $920,000Total Purchased Equipment Costs (TEC):Sum of 1A, 1B and1C$11,880,000 $12,420,0002. Installation Costs:A) Foundation & Supports8% of TEC$950,400 $993,600B) Erection and Handling14% of TEC$1,663,200 $1,738,800C) Electrical4% of TEC$475,200 $496,800D) Piping5% of TEC$594,000 $621,000E) Insulation2% of TEC$237,600 $248,400F) Painting1% of TEC$118,800 $124,200G) Site Preparation3% of TEC$356,400 $372,600Total Installation Costs (TINC):$4,395,600 $4,595,400Total Direct Capital Costs (TDCC):Sum of TEC andTINC$16,275,600 $17,015,400INDIRECT CAPITAL COSTS1. Engineering & Supervision15% of TEC$1,782,000$1,863,0002. Construction and Field Expenses5% of TEC$594,000 $621,0003. Contractor Fees10% of TEC$1,188,000 $1,242,0004. Start-up2% of TEC$237,600$372,600In the EM estimate, 3% is the factor used for Start-up basedon ExxonMobil experience instead of the EPA 2% basis.5. Performance Testing2% of TEC$237,600$372,600In the EM estimate, 3% is the factor used for Performance Testbased on ExxonMobil experience instead of the EPA 2% basis.6. Government Permitting & Fees1% of TEC$124,200In the EM estimate, 1% is added for Government Permittingand Fees based on ExxonMobil experience.EPA Cost Control ManualTABLE 4-6aMcElmo Gas Compression FacilityReplace HOS-6 CompressorCapital Cost AnalysisItemExxonMobil Assumptions ExxonMobil CommentsEPA Cost Control ManualTABLE 4-6aMcElmo Gas Compression FacilityReplace HOS-6 CompressorCapital Cost AnalysisTotal Indirect Capital Costs (TICC):Sum of 1, 2, 3, 4and 5$4,039,200 $4,595,400Total Direct & Indirect Capital Costs (TDICC):Sum of TDCC andTICC$20,314,800 $21,610,800Owners Cost$2,593,296In the EM estimate, 12% is added for Owner Costs based onExxonMobil experience to cover the project management teamrequired to oversee the design, construction andcommissioningcontractors.Contingency20% of TDICC$4,062,960$6,483,240In the EM estimate, 30% is the factor used for Contingencybased on ExxonMobil experience instead of the EPA 20%basis. The EPA cost control manual states that this type ofcost estimate (a "study estimate") has a +/- 30% accuracy.TOTAL CAPITAL COSTS (TCC):Sum of TDICC andContingency$24,377,760 $30,687,336ItemExxonMobil Assumptions ExxonMobil CommentsDIRECT OPERATING COSTS1. Operating Labor2 hr/shift @ $20/hr, 3shifts/day, 365 days/yr$43,800 $43,8002. Supervisory Labor 15% of Operating Labor$6,570 $6,5703. Maintenance Labor & Materials 2% of TCC$487,555$920,620In the EM estimate, 3% is the factor used forMaintenance Labor & Materials based on ExxonMobilexperience instead of the EPA 2% basis.Total Direct Operating Costs (TDOC):Sum of 1 - 9$537,925 $970,990INDIRECT OPERATING COSTS1. Overhead60% of Total Labor +Maintenance$322,755 $582,594Total Indirect Operating Costs (TIOC):$322,755 $582,594CAPITAL CHARGES COSTS1. Property Tax 1% of TCC$243,778 $306,8732. Insurance 1% of TCC$243,778 $306,8733. General Administrative 2% of TCC$487,555 $613,7474. Capital Recovery FactorCRF = 0.1061 [10% @30 yr.]$2,586,480 $3,255,926Total Capital Charges Costs (TCCC):Sum of 1, 2, 3 and 4$3,561,591 $4,483,420TOTAL ANNUALIZED OPERATING COSTS:Sum of TDOC, TIOC andTCCC$4,422,271 $6,037,00475% control of annual SO2emissions (.95 x 44.2 tpy) =42.0$105,317per ton of SO2removal75% control of annual CO emissions (.95 x 135.1 tpy) =128.3$34,456per ton of CO removal75% control of annual NOx emissions (.95 x 24.8 tpy) =23.6$187,703per ton of NOxremoval75% control of annual VOC emissions (.95 x 151.8 tpy) =144.2$30,665per ton of VOC removalEPA Cost Control ManualTABLE 4-6bMcElmo Gas Compression FacilityReplace HOS-6 CompressorOperating Cost AnalysisItemExxonMobil Assumptions ExxonMobil CommentsDIRECT CAPITAL COSTS1. Purchased Equipment:A) EquipmentBase Cost$11,300,000$11,300,000B) Instrumentation & Controls10% of Base Cost$1,130,000$1,695,000In the EM estimate, 15% is the factor used for Instrumentationbased on ExxonMobil experience instead of the EPA 10%basis. The EPA cost cost control manual states that factorsrange from 5% to 30%.C) Freight & Taxes4% Taxes; 4%Freight on 1A & 1B$994,400 $1,039,600Total Purchased Equipment Costs (TEC):Sum of 1A, 1B and1C$13,424,400 $14,034,6002. Installation Costs:A) Foundation & Supports8% of TEC$1,073,952 $1,122,768B) Erection and Handling14% of TEC$1,879,416 $1,964,844C) Electrical4% of TEC$536,976 $561,384D) Piping5% of TEC$671,220 $701,730E) Insulation2% of TEC$268,488 $280,692F) Painting1% of TEC$134,244 $140,346G) Site Preparation3% of TEC$402,732 $421,038Total Installation Costs (TINC):$4,967,028 $5,192,802Total Direct Capital Costs (TDCC):Sum of TEC andTINC$18,391,428 $19,227,402INDIRECT CAPITAL COSTS1. Engineering & Supervision15% of TEC$2,013,660$2,105,1902. Construction and Field Expenses5% of TEC$671,220 $701,7303. Contractor Fees10% of TEC$1,342,440 $1,403,4604. Start-up2% of TEC$268,488$421,038In the EM estimate, 3% is the factor used for Start-up basedon ExxonMobil experience instead of the EPA 2% basis.5. Performance Testing2% of TEC$268,488$421,038In the EM estimate, 3% is the factor used for Performance Testbased on ExxonMobil experience instead of the EPA 2% basis.6. Government Permitting & Fees1% of TEC$140,346In the EM estimate, 1% is added for Government Permittingand Fees based on ExxonMobil experience.EPA Cost Control ManualTABLE 4-7aMcElmo Gas Compression FacilityFlare Gas Recovery SystemCapital Cost AnalysisItemExxonMobil Assumptions ExxonMobil CommentsEPA Cost Control ManualTABLE 4-7aMcElmo Gas Compression FacilityFlare Gas Recovery SystemCapital Cost AnalysisTotal Indirect Capital Costs (TICC):Sum of 1, 2, 3, 4and 5$4,564,296 $5,192,802Total Direct & Indirect Capital Costs (TDICC):Sum of TDCC andTICC$22,955,724 $24,420,204Owners Cost$2,930,424In the EM estimate, 12% is added for Owner Costs based onExxonMobil experience to cover the project management teamrequired to oversee the design, construction andcommissioningcontractors.Contingency20% of TDICC$4,591,145$7,326,061In the EM estimate, 30% is the factor used for Contingencybased on ExxonMobil experience instead of the EPA 20%basis. The EPA cost control manual states that this type ofcost estimate (a "study estimate") has a +/- 30% accuracy.TOTAL CAPITAL COSTS (TCC):Sum of TDICC andContingency$27,546,869 $34,676,690ItemExxonMobil Assumptions ExxonMobil CommentsDIRECT OPERATING COSTS1. Operating Labor2 hr/shift @ $20/hr, 3shifts/day, 365 days/yr$43,800 $43,8002. Supervisory Labor 15% of Operating Labor$6,570 $6,5703. Maintenance Labor & Materials 2% of TCC$550,937$1,040,301In the EM estimate, 3% is the factor used forMaintenance Labor & Materials based on ExxonMobilexperience instead of the EPA 2% basis.Total Direct Operating Costs (TDOC):Sum of 1 - 9$601,307 $1,090,671INDIRECT OPERATING COSTS1. Overhead60% of Total Labor +Maintenance$360,784 $654,402Total Indirect Operating Costs (TIOC):$360,784 $654,402CAPITAL CHARGES COSTS1. Property Tax 1% of TCC$275,469 $346,7672. Insurance 1% of TCC$275,469 $346,7673. General Administrative 2% of TCC$550,937 $693,5344. Capital Recovery FactorCRF = 0.1061 [10% @30 yr.]$2,922,723 $3,679,197Total Capital Charges Costs (TCCC):Sum of 1, 2, 3 and 4$4,024,598 $5,066,264TOTAL ANNUALIZED OPERATING COSTS:Sum of TDOC, TIOC andTCCC$4,986,689 $6,811,33775% control of annual SO2emissions (.75 x 44.2 tpy) =33.2$150,428per ton of SO2removal75% control of annual CO emissions (.75 x 135.1 tpy) =101.3$49,215per ton of CO removal75% control of annual NOx emissions (.75 x 24.8 tpy) =18.6$268,102per ton of NOxremoval75% control of annual VOC emissions (.75 x 151.8 tpy) =113.9$43,801per ton of VOC removalEPA Cost Control ManualTABLE 4-7bMcElmo Gas Compression FacilityFlare Gas Recovery SystemOperating Cost Analysis

### 5-1 5.0 EXISTING ENVIRONMENT

5.1 TOPOGRAPHY

The McElmo Creek Oil Production Facility is lo cated on Navajo Nation land in southeastern Utah, in San Juan County, near the town of An eth. The gas compression facility is located approximately 23 km (14 miles) northwest of th e Utah / Colorado border and 4.8 km (3 miles) north of State Highway 262. Arches National Pa rk and Canyonlands Nati onal Park are located to the northwest, approximately 160 km (100 mile s) and 96 km (60 miles), respectively. Mesa Verde National Park is located approximately 60 km (38 miles) east of the gas compression facility site. The western boundary of the Canyon of the Ancients National Monument is approximately 16 km (10 miles) northwest of the plant site.

Elevations around the gas compression plant range from 5,500 feet to 5,900 feet. Terrain generally increases in both the north and south directions from the east-west valley formed by the San Juan River. Ground cover is relatively sparse because of the semiarid climatic conditions surrounding the gas co mpression facility site.

5.2 AIR QUALITY

Background air quality monitoring data for 1999-2003 are presented in Table 5-1 for ozone (O 3 

### ), nitrogen dioxide (NO 2 

### ), carbon monoxide (CO), and sulfur dioxide (SO 2 

### ). Ozone concentrations are cited as surrogate for VOC impacts because VOCs do not have an ambient air quality standard; rather, VOC is considered a contributor to the formation of O 3



### .

No site or area-specific data was av ailable for southeastern Utah for NO 2 

### , CO, SO 2 

### and O 3 

### ; therefore, air quality data gath ered from monitoring stations located in north central Utah, primarily within the Salt Lake City metropolitan area, are used as conservative indicators of air quality for this rural ar ea of Utah. Background PM 10 

### concentrations are not addressed since

PM 10 

### emissions are insignificant from a flare, and the Consent Decree does not cite emission

limits for PM 10



### .

### 5-2 Table 5-1. Air Quality in the McElmo Creek Area.

Pollutant Monitor Location/County 1 Year Averaging Period Maximum ppm/ μg/m 3 Annual Mean ppm / μg/m 3 NAAQS ppm μg/m 3

Ozone (O 3 ) Spanish Fork/Utah Spanish Fork/Utah Spanish Fork/Utah Spanish Fork/Utah Spanish Fork/Utah 1999 2000 2001 2002 2003 8 hour 8 hour 8 hour 8 hour 8 hour 0.102 / 200 0.100 / 196 0.081 / 159 0.081 / 159 0.080 / 157 0.08 2 157

Nitrogen Dioxide (NO 2 ) North Provo/Utah North Provo/Utah North Provo/Utah North Provo/Utah North Provo/Utah 1999 2000 2001 2002 2003 Annual Annual Annual Annual Annual 0.024 / 45 0.024 / 45 0.024 / 45 0.025 / 47 0.022 / 41 0.053 100

Carbon Monoxide (CO) North Provo/Utah North Provo/Utah North Provo/Utah North Provo/Utah North Provo/Utah 1999 2000 2001 2002 2003 8 hours 8 hours 8 hours 8 hours 8 hours 5 / 5,726 4 / 4,581 4 / 4,581 4 / 4,581 3 / 3,436 35 40,000

Sulfur Dioxide (SO 2 ) North Salt Lake/Salt Lake North Salt Lake/Salt Lake North Salt Lake/Salt Lake North Salt Lake/Salt Lake North Salt Lake/Salt Lake 1999 2000 2001 2002 2003 3 hours 3 hours 3 hours 3 hours 3 hours 0.033 / 86 0.042 / 110 0.041 / 107 0.052 / 136 0.036 / 94 No data No data No data No data No data 0.50 1,300

North Salt Lake/Salt Lake North Salt Lake/Salt Lake North Salt Lake/Salt Lake North Salt Lake/Salt Lake North Salt Lake/Salt Lake 1999 2000 2001 2002 2003 24 hours 24 hours 24 hours 24 hours 24 hours 0.012 / 31 0.014 / 37 0.013 / 34 0.010 / 26 0.015 / 39 No data No data No data No data No data 0.14 365

1. No site-specific data is available. These m onitoring locations provide th e closest available data. 2. To attain this standard, the 3-year average of the f ourth-highest daily maximum 8-hour average ozone concentrations measured at each monitor within an area over each year must not exceed 0.08 ppm.



### This table shows that with the exception of ozone, all pollutants are well below the National Ambient Air Quality Standards (NAAQS). Note that compliance with the 8-hour ozone NAAQS is based on the 3-year average of the 4 th 

### highest daily maximum value; Table 5-1 presents only

the 1 st 

### highest ozone value for each year and cannot directly be compared to the 8-hour ozone standard. However, these concentrations repr esent maximum worst-case background conditions as an indicator of potential co mpliance with the ozone NAAQS.

5.3 AREA CLIMATE AND METEOROLOGY

The southeastern area of the state, where th e McElmo Creek facility is located, can be

characterized as an area of low precipitation, high summer temper atures, and moderate winter temperatures. Meteorological monitoring has no t been conducted onsite at the McElmo Creek facility. The nearest meteorological monitoring station with available data is located by

### 5-3 International Uranium Corporation’s White Mesa Mill near Blanding, Uta h. This data can be considered as representative of the southeaste rn Utah area. The annual 2004 wind frequency distribution is presented in Table 5-2, and graphically as a wind ro se in Figure 5-1. The average wind speed for 2004 was 3.4 meters/second (m/s), or 7.6 miles per hour (mph). The predominant

wind directions were from the north-northeast (15.5%), from the north (11%), and from the south-southwest (10.8%). Annual atmospheric stab ility distribution for 2004 is in Table 5-3.

Table 5-3. Annual Stability Cla ss Distribution at Blanding, Utah.

Stability Class Percent of Occurrence (%)

A 15.2

B 10.1

C 12.2

D 36.0

E 13.2

F 13.3



### Temperature and precipitation c onditions in vicinity of the Mc Elmo Gas Compression Facility are depicted by a long-term climatic monthl y summary (12/8/1904 – 3/31/2005) of data from Blanding, Utah in Table 5-4.

Table 5-4. Monthly Average Temperature an d Total Precipitation at Blanding, Utah.

Month Avg. Temp. Max. ( o F) Avg. Temp. Min. ( o F) Avg. Temp. Mean ( o F) Precipitation Total (inches) January 39.1 17.1 28.1 1.39 February 44.8 22.3 33.6 1.23

March 52.7 27.8 40.3 1.04 April 62.2 34.3 49.3 0.87 May 72.2 42.0 57.1 0.71

June 83.3 50.7 67.0 0.45 July 88.6 57.8 72.2 1.15 August 86.2 56.1 71.1 1.39 September 78.2 48.3 63.3 1.28

October 66.0 37.9 51.9 1.45

November 51.4 26.6 41.0 1.06

December 41.1 19.1 30.1 1.35 Annual Avg. Temp./Annual Total Precip. 63.8 36.7 50.3 13.35

### 5-4 5.4 SOILS AND VEGETATION

Soils within this area of Utah have textural, depth, and drainage characteristics that limit the

amount of water the soils can hold and make av ailable for plant growt h. Vegetation in the vicinity of the project area is sp arse, predominantly sagebrush with scattered grasses and forbs. No listed threatened or endangered plant species are known to occur within the project area.**Table 5-2**

10 METER WIND DATA ANALYSIS

FROM 1/ 1/2004 THROUGH 12/31/2004

INTERNATIONAL URANIUM METEOROLOGICAL STATION

FREQUENCY OF OCCURRENCE OF WIND SPEED BY DIRECTION

+----------WIND SPEED CLASSES (M/S)----------+ AVERAGE 0.0- 1.8- 3.3- 5.4 8.4 > WIND DIR 1.8 3.3 5.4 8.4 11.0 11.0 TOTAL SPEED

------------------------------------------------------------------------- N .0141 .0514 .0388 .0052 .0004 .0000 0.110 3.2

NNE .0216 .0895 .0360 .0028 .0012 .0001 0.151 2.9

NE .0231 .0370 .0098 .0018 .0005 .0000 0.072 2.5

ENE .0124 .0121 .0043 .0013 .0000 .0000 0.030 2.4

E .0082 .0072 .0031 .0008 .0000 .0000 0.019 2.5

ESE .0085 .0091 .0024 .0012 .0000 .0000 0.021 2.4

SE .0097 .0186 .0095 .0028 .0002 .0000 0.041 3.4

SSE .0108 .0242 .0112 .0018 .0006 .0000 0.049 2.9

S .0100 .0375 .0254 .0079 .0014 .0000 0.082 3.5

SSW .0073 .0352 .0376 .0199 .0057 .0020 0.108 4.4

SW .0073 .0227 .0197 .0170 .0026 .0011 0.070 4.3

WSW .0054 .0134 .0109 .0105 .0020 .0001 0.042 4.3

W .0064 .0109 .0098 .0082 .0004 .0004 0.036 3.9

WNW .0071 .0117 .0078 .0033 .0000 .0000 0.030 3.2

NW .0087 .0179 .0162 .0095 .0017 .0000 0.054 3.9

NNW .0110 .0218 .0322 .0164 .0026 .0002 0.084 4.1

------------------------------------------------------------------------- TOT: 0.172 0.420 0.275 0.110 0.019 0.004 1.000 AVG: 1.4 2.6 4.2 6.7 9.4 12.0 3.4

TOTAL NUMBER OF VALID READINGS FOR THIS TABLE => 8456 OUT OF 8456 TOTAL VALID HOURS TOTAL NUMBER OF MISSING HOURS => 328 TOTAL NUMBER OF CALM HOURS => 41WRPLOT View - Lakes Environmental Software White Mesa Mill - Blanding, Utah

DATE:

1/19/2005 PROJECT NO.: 

### 1721-03 COMMENTS:

PREPARED BY: McVehil-Monnett Associates COMPANY: International Uranium Corporation NORTH

SOUTH WEST EAST 4% 8% 12% 16% 20%

W I N D S P E E D ( m / s )

> = 1 1

. 1

8

. 8

- 1 1

. 1

5

. 7

- 8

. 8

3

. 6

- 5

. 7

2

. 1

- 3

. 6

0

. 5

- 2

. 1

C a l m s : 0

. 1 5 %

TOTAL COUNT:

8456 hrs. CALM WINDS:

0.15% DATA PERIOD:

2004 Jan 1 - Dec 31 00:00 - 23:00

AVG. WIND SPEED:

3.43 m/s Wind Speed Direction (blowing from)

### 6-1 6.0 IMPACT ASSESSMENT APPROACH

This section presents the methodology used to eval uate the potential ambient air quality impacts resulting from the operation of the Main Flare. These analyses are compared against the National Ambient Air Quality Standards (NAAQS) a nd PSD increments presented in Table 6-1.

TABLE 6-1 SUMMARY OF NATIONAL AMBIENT AIR QUALITY STANDARDS AND PSD INCREMENTS

NAAQS Class II PSD Averaging Primary Increment

Pollutant Time μ g/m 3 (ppm) μ g/m 3 (ppm)

1-hour a 40,000 (35) -- Carbon Monoxide

8-hour a 10,000 (9) --

Nitrogen Dioxide Annual (arith. mean) 100 (0.05) 25 (0.013)

Ozone 8-Hour b (0.08) --

24-hour a 150 (--) 30 (--) Particulates (PM 10 )

Annual (arith. mean) 50 (--) 17 (--)

3-hour a 1,300 (0.50) 512 (0.20)

24-hour a 365 (0.14) 91 (0.035) Sulfur Dioxide

Annual (arith. mean) 80 (0.03) 20 (0.008)

Lead Calendar Quarter (arith. mean) 1.5 (--) --

a. Not to be exceeded more than once per year. b. The 3-year average of the 4 th highest daily maximum concentrations must not exceed this standard.

### 6-2 6.1 AIR QUALITY MODEL DESCRIPTION

SCREEN3 is an EPA-approved screening model fo r estimating near-field impacts from a single emission source or group of emission sources th at can be characterized from one location. SCREEN3 utilizes Gaussian dispersion to es timate concentrations w ithin a plume, with maximum impacts estimated at the plume centerline. Version 96043 of SCREEN3 was used for this application.

SCREEN3 transport is assumed to instantaneously occur at specified receptor distances from the source with specific dispersion dependent upon the atmospheric stability class, using Pasquill stability categories and wind speed . The intended use of SCREEN 3 is for short-term averaging periods on the order of one hour or less. Howe ver, estimated maximum short-term impacts can be extrapolated to longer averaging period s by adjustment factors referenced from the “Screening Procedures for Estimating the Air Qu ality Impact of Stationary Sources” (EPA, 1992). These factors are intended to account for long-term wind direction meander as

summarized below:

Averaging Time Multiplying Factor

3 hours 0.9

8 hours 0.7

24 hours 0.4

Annual 0.08



### The SCREEN3 model is most suita ble for estimating concentrations for distances greater than 100 meters from the source and for source plume heights less than 300 meters. In addition, SCREEN3 internally examines a full range of meteorological conditions, representative of possibly occurring stability class and wind speed combinations to find maximum impacts.

The SCREEN3 model also simula tes the effects of buoyancy-induced dispersion (BID). The

inclusion of BID in SCREEN3 can affect estimat ed concentrations, depending on the source and distance. For sources with plume heights belo w 300 meters, the effect of BID on estimated maximum concentrations will usually be less than about ± 10 percent. For elevated sources with relatively large buoyancy, the inclusion of BID ma y be expected to decrease the estimated maximum concentration by as much as 25 percent.

### 6-3 6.2 MODEL INPUT

The Main Flare is a point (stack) source that rout inely operates in the stand-by mode as reflected in the annual emissions presented as limits in Se ction 3. For modeling purposes, particularly for comparison to short-term standards and PSD increments, the worst-case impacts from the Main Flare would be during an upset episode when all pro cess gas is sent to the flare, rather than reinjected into the ground. Thus, modeled flar e stack parameters were based on using the buoyancy flux algorithm in SCREEN3. This algorithm estimates an effective stack diameter at an assumed stack velocity of 20 m/s at the estima ted heat release (in calories per second) of the flare when combusting all process gas th at would otherwise be re-injected.

Modeling was performed to estimate impacts of NO 2 

### , CO and SO 2 

### only, since PM 10 

### emissions are insignificant and VOCs are not modeled directly except as a precursor to ozone. The annual emission limit for VOCs (95.4 tons per year) is below the 100 ton per year criterion typically cited as that level requiring ozone modeling.

Refer to Section 6.4 for additi onal information about source ch aracteristics and emission rates used in the model input.

6.3 METEOROLOGICAL DATA

The selection of an appropriate meteorological data set for air quality modeling is based on proximity to the project site, similarity of t opography and conformity of the data collection and reporting procedures to PSD m onitoring requirements. Anothe r consideration is that the meteorological data can be readil y processed into a format compa tible for use in air dispersion modeling.

For this screening model application, the full a rray of 44 discrete me teorological conditions internally generated by SCREEN3 was used to es timate potential worst- case short-term (i.e., one-hour averaged) impacts for each modeled po llutant. The maximu m impact cited by SCREEN3 from a specific discrete meteorological condition (wind spee d, stability class and mixing height combination) and receptor distance was used as the basis for estimating maximum pollutant impacts. The maximum one-hour impact for each pollutant was extrapolated to values

### 6-4 for each averaging period for which a pollutant has an applicable NAAQS and PSD increment, using the adjustment factor s referenced in Section 6.1.

6.4 SOURCE CHARACTERISTI CS AND EMISSION RATES

6.4.1 Flare Rate and Heat Release

Short-term pollutant emission rates were estim ated by assuming that the maximum volume of process gas that could be generated from the well fi eld would be sent to the flare at four different heat content values (in BTU/SCF). These four h eat content values represent a range of estimates including the lowest allowable LHV, the lowe st LHV from 2004 gas analyses, the lowest LHV from 2005-08 gas analyses and the highest LHV from 2005-08 gas analyses data. The lowest value input was 300 BTU/scf, which is the lo west allowable LHV as stated in 40 CFR 60.18(c)(3)(ii). The next lowest value utilized was 443 BTU/scf, which is the lowest of four 2004 actual plant gas samples from McElmo. (The four analyses are dated 4/28/04, 5/27/04, 8/29/04, and 9/29/04; and their LHV values were 443, 505, 512, and 453 BTU/scf, respectively.)

The LHV of 443 BTU/scf was utilized due to th e assumption that it would provide the least amount of heat rise, thus produci ng the lowest effective release he ight. The lowest and highest LHVs from 2005-08 gas analyses data of 538.8 a nd 682.4 BTU/scf, respectively, were also used for emission estimation. The resultant range of BTU contents and effective release heights were modeled to evaluate the sensitivity of impact s to each emission rate/effective release height

combination.

The maximum flare rate utilized was 689,423 acf/h r (618,104 scf/hr), which assumes that the flare is operating at 14.83 MCFD for the entire year. The flare rate value of 618,104 scf/hr was based on the assumption that the ne w flare tip will be 24 inches in diameter and will have a flare tip exit velocity of 64.74 ft/s. This exit velocity is below the maximum ex it velocity as specified by 40 CFR 60.18, which is 66.98 ft/s.

The heat released from the flare tip was then cal culated and converted to a rate of calories per

second based on the conversion of 1 BTU = 252.1644 calories. The equation used for this

calculation is as follows:

### 6-5 

### s cal V LHV s cal heat 3600 ) 1644

. 252 )( )( ( ) / ( =

Where: LHV = lower heating va lue of gas burned (BTU/scf) V = 618,104 scf/hr.

6.4.2 Flare Height



### The actual flare stack height of 195 feet wa s taken from drawing D-SA-107 as provided by Zeeco, Inc. from 1991. This measurement was fi eld verified to ensure proper stack height.

6.4.3 Modeled Emission Rates



### The emission factors for NO x 

### and CO were derived by the Chemical Section of the Texas Commission on Environmental Quality NSR Di vision based on data published in the 1983

Chemical Manufacturer's Association document entitled "A Report On A Flare Efficiency Study." The factors used were as follows:

NO x 

### = 0.0641 lb/MMBTU

CO = 0.5496 lb/MMBTU.

Therefore, the equation used to calculate the emission rate for NO x 

### and CO contaminants at the specified LHV is as follows:

s hr lb g MMBTU lb EF BTU MMBTU scf BTU LHV hr scf V s g rate 3600 * 59

. 453 * * 10 * * ) / ( 6 

### =

Where: V = 618,104 scf/hr LHV = lower heating value of gas burned (BTU/scf) EF = emission factor (lb/MMBTU).

### 6-6 Regarding the SO 2 

### emission calculation, recent tests at th e McElmo site indicate the plant inlet gas contains approximately 500 ppm H 2 

### S. However, it was assumed th at the flared gas contains 700 ppm H 2 

### S on the SCREEN3 SO 2 

### dispersion model. This H 2 

### S value was used in order to provide a conservati ve estimate of SO 2 

### emissions from the flare. The emission rate was

calculated as follows:

rate (g/s) = (618,104 scf/hr * 700 ppm * 64 lb/lb-mole SO 2 )/(380 scf/lb-mole * 1,000,0 00 ppm)= 72.87 lbSO 2 /hr



### In summary, the stack parameters and estimated emission rates for the Main Flare at the four representative heat content values during upset conditions are summarized below in Table 6-2.

Table 6-2

SCREEN3 Modeled Stack Parameters and Emissions for the Main Flare (Maximum Volumetric Process Gas Flow of 618,104 SCF/hr)

Heat

Content (BTU/SCF) Total Heat

Release (cal/sec) Stack Height

(m.) Effective

Release Height (m.) Stack Velocity

(m/s) Short-Term

NO x Emission Rate (gm/sec) Short-Term

SO 2 Emission Rate (gm/sec) Short-Term

CO Emission Rate (gm/sec) 300 12,988,700 59.45 70.9117 20.0 1.50 9.18 12.84 443 19,179,900 59.45 73.2591 20.0 2.21 9.18 18.96 538.8 23,327,600 59.45 74.6137 20.0 2.69 9.18 23.06 682.4 29,544,900 59.45 76.4268 20.0 3.41 9.18 29.21



### 6.5 RECEPTOR SELECTION



### Receptor points were generated using the automa ted grid option of SCREEN3, starting at 200 meter from the Main Flare and extending out to 4,000 meters. Since the flare is a highly buoyant source with a stack height of nearly 60 meters, in-close im pacts would be minimal and maximum ground-level impacts would likely be located at least one or mo re kilometers away from the stack. Receptors were placed at 100 meter intervals from 200 to 5,000 meters.

Since terrain within 5 kilometers of the Main Fl are is relatively flat, SCREEN3 was run in the simple terrain mode and all recept or elevations were assumed to be at the elevation of the Main

Flare stack base.

### 6-7 6.6 CLASS I AREA IMPACTS



### A telephone conversation with Mr. John Notar of the National Park Service on June 15, 2006, followed up by an e-mail message from Mr. Nota r dated June 21, 2006, provided guidance on the level of detail required for the Class I area impact analysis. Mr. Notar indicated in his

6/21/06 e-mail that estimated emissions from the flare are sufficiently small to not require a detailed quantitative analysis of ambient air quality and air qua lity related value impacts on nearby Class I and sensitive Class II areas. A ppendix D contains documentation of Mr. Notar’s guidance in his 6/21/06 e-mail.

A general discussion of ambient air quality impacts is presented based on the SCREEN3 modeling results at a receptor di stance of 50 km. away from the modeled flare emissions. The selection of a receptor di stance of 50 km. is based on regulat ory guidance stating that 50 km. is the furthest distance at which application of a near-field model is deemed appropriate. VISCREEN was used to estimate visibility imp acts at the nearest Class I area, Mesa Verde National Park (approximately 60 km. from the McElmo Gas Compression Facility). Annual averaged ambient air quality impacts of NO x 

### and SO 2 

### based on SCREEN3 modeling were used to estimate deposition impacts.

6.7 ADDITIONAL IMPACTS ANALYSIS



### EPA Region IX’s comment letter of May 22, 2006 stated that additional impacts from secondary growth, soils and vegetation and vi sibility impairment must be pe rformed even for a source with

small emissions. These additi onal impacts are addressed by:

1. No secondary growth is associated with Main Flare operations as existing manpower used for operation of the McElmo Gas Compression Facility is sufficient.

2. Soils and vegetation impacts are addressed by deposition considerations presented in

Section 7.4.3.

3. Visibility impairment is addressed in S ection 7.4.2 and VISCREEN has been used to estimate visibility impacts.

### 6-8 6.8 ENDANGERED SPECIES



### The effect on threatened and endangered species and critical habitat within the region surrounding Aneth, Utah would be assessed if di scernible effects are d eemed to potentially occur. Mr. Henry Maddux, Utah Endangered Sp ecies Field Supervisor , was contacted to determine if such an effects analysis is n ecessary. Mr. Maddux responded via an e-mail dated June 29, 2006 that the Main Flar e emissions addressed in the C onsent Decree have no effect on listed species and their critical habitat in the region surrounding Aneth, Utah. Therefore, no further analyses of effects on endangered sp ecies and critical hab itat were performed.

Appendix D contains documentation of Mr . Maddux’s guidance in his 6/29/06 e-mail.

### 7-1 7.0 AIR QUALITY IMPACTS



### This section presents modeled air quality impact s of the Main Flare facility to demonstrate compliance with the National Ambient Air Quality Standards (NAAQS) and Prevention of Significant Deterioration Increments for Class II Areas. Air quality impacts are presented from the Main Flare alone and combined with repres entative ambient air background concentrations for an assessment of cumulative impacts.

As discussed in the previous section, in order to conservatively calculate emission rates from the Main Flare for use in this modeling analysis, several assumptions were made. Many of these assumptions were made with the intent of providing conservative estimates including:

1. Consideration of a range of heat value ratings and corres ponding effective release heights for the gas at McElmo to evaluate a nd identify maximum im pacts produced by the McElmo Main Flare; 2. The maximum design flare rate of 14.83 MCFD; and

3. The H 2 

### S concentration of 700 ppm instead of the actual measured value of approximately 450 ppm.

Emission limitations established by the Consent Decree for the Ma in Flare are 60 tons per year

of SO 2 

### , 73 tons per year of CO, 13.4 tons per year of NO x 

### , and 94.5 tons per year of VOC. However, the worst-case conditions based on th e modeled maximum flare rate of 14.83 MCFD

and LHV of 682.4 BTU/scf result in em issions of 319.12 tons per year of SO 2 

### , 1,015.41 tons per year of CO, and 118.54 tons per year of NO x 

### . These very conservative worst-case conditions result in emission rates in the analysis that are at least five times greater than current air permit limits. In addition, the actual fi eld conditions are not capable of sustaining a flow rate of 14.83

MCFD. The remainder of this section will show that even with these worst-case emission estimates that far exceed the current air perm it limits and actual flow rate conditions, the modeling results show no exceedances of the NAAQS or the PSD Class II Increments.

Hard copies of the SCREEN3 model run input a nd output are contained in Appendix B. Model

runs for estimated NO 2 

### , CO and SO 2 

### impacts for process gas with a heat content of 300, 443, 538.8 and 682.4 BTU/SCF were generated.

### 7-2 7.1 NITROGEN DIOXIDE (NO 2 

### )



### The Main Flare was modeled at the heat content scenarios of 300, 443, 538.8 and 682.4 BTU/SCF. The modeled impact concentratio ns from SCREEN3 were multiplied by a factor 0.75, the default ozone limiting factor, and the a nnual averaging period adjustment factor of 0.08. The ozone limiting factor takes into acco unt the conversion of NO (the majority of a NO X 

### release) to NO 2 

### by reacting with ozone, assuming that approximately 75% is converted as a longterm average. A maximum background annual averaged NO 2 

### concentration from Table 5-1 of 47 μg/m 3 

### is cited as the value to add to the maximum modeled annual NO 2 

### impact to obtain an estimate of cumulative impacts for comparison to the NO 2 

### NAAQS.

7.1.1 Increment Consumption



### Table 7-1 summarizes estimation of the maximum annual averaged NO 2 

### impact from the Main Flare, with a heat content of 300, 443, 538.8 an d 682.4 BTU/SCF. The resultant values from the Main Flare are compared to the annual NO 2 

### PSD Class II Increment.

Table 7-1 Comparison of Modeled Main Flare NO 2 

### Impacts to the PSD Increment

Max. Modeled Max. Adjusted Heat One-Hour Modeled PSD Class II Percent of Content Concentration Averaging Adjustme nt Concentration Increment Increment (BTU/SCF) (ug/m 3 ) Period Factor a (ug/m 3 ) (ug/m 3 ) (%)

300 1.893 Annual 0.06 0.11 25 0.44% 443 2.148 Annual 0.06 0.13 25 0.52% 538.8 2.376 Annual 0.06 0.14 25 0.56% 682.4 2.456 Annual 0.06 0.15 25 0.59% a. Combination of ozone limiting adjustment factor of 0.75 and the annual averaging period adjustment factor of 0.08. (0.75 x 0.08 = 0.06)



### The predicted maximum annual averaged concen tration from the Main Flare is 0.15 μg/m 3 

### located 1,174 meters from the flare stack. Th is maximum concentration is approximately only 0.59% of the PSD Class II increment of 25 μg/m 3 

### . In addition, the maximum annual concentration is only 15% of the Class II significant impact level (SIL) of 1 μg/m 3



### .

### 7-3 7.1.2 National Ambient Air Qu ality Standards (NAAQS)



### Table 7-2 provides a comparison of the estimated cumulative maximum annual averaged NO 2 

### impact from the Main Flare, with a heat content of 300, 443, 538.8 and 682.4 BTU/SCF, to the

annual NO 2 

### NAAQS. The modeled results are added to the cited backgr ound concentration to arrive at the estimated cumulative concentration, and the total value is compared to the annual

NO 2 

### NAAQS.

Table 7-2. Comparison of Modeled Cumulative NO 2 

### Impacts to the NAAQS

Max. Modeled Max. Adjusted Monitored Maximum National Heat One-Hour Modeled Background Cumulative Ambient Air Percent of Content Concentration Averaging Adjustment Concentr ation Concentration Concen tration Quality Std. NAAQS (BTU/SCF) (ug/m 3 ) Period Factor (ug/m 3 ) (ug/m 3 ) (ug/m 3 ) (ug/m 3 ) (%)

300 1.893 Annual 0.06 0.11 47.00 47.11 100 47.11% 443 2.148 Annual 0.06 0.13 47.00 47.13 100 47.13% 538.8 2.376 Annual 0.06 0.14 47.00 47.14 100 47.14% 682.4 2.456 Annual 0.06 0.15 47.00 47.15 100 47.15%



### The predicted maximum annual averaged concen tration from the Main Flare is 0.15 μg/m 3 

### located 1,174 meters from the flare stack. This maximum concentration, added to the background concentration of 47 μg/m 3

, 

### results in a cumulative concentration which is approximately 47.15% of the NAAQS.

7.2 SULFUR DIOXIDE (SO 2 

### )



### The Main Flare was modeled at the heat content scenarios of 300, 443, 538.8 and 682.4 BTU/SCF. The modeled impact concentrations from SCREEN3 were multiplied by the 3-hour, 24-hour and annual averagin g period adjustment factors of 0. 90, 0.40 and 0.08, respectively. Maximum background 3-hour, 24-ho ur and annual averaged SO 2 

### concentration from Table 5-1 of 136, 39 and 39 μg/m 3 

### are cited as the values to add to the maximum modeled SO 2 

### impacts

from the Main Flare to obtain an estimate of cumulative impacts for comparison to the SO 2 

### NAAQS. Note that the cited 24-hour backgr ound concentration has been assumed to also

### 7-4 represent the annual background c oncentration since no specific a nnual averaged monitoring

data were available.

7.2.1 Increment Consumption



### Table 7-3 summarizes estimation of the ma ximum 3-hour, 24-hour and annual averaged SO 2 

### impacts from the Main Flare, with a heat c ontent of 300, 443, 538.8 and 682.4 BTU/SCF. The resultant maximum values from the Main Flare are compared to the SO 2 

### PSD Class II

Increments.

Table 7-3 Comparison of Modeled Main Flare SO 2 

### Impacts to the PSD Increment

Max. Modeled Max. Adjusted Heat One-Hour Modeled PSD Class II Percent of Content Concentration Averaging Adjustme nt Concentration Increment Increment (BTU/SCF) (ug/m 3 ) Period Factor (ug/m 3 ) (ug/m 3 ) (%)

300 11.63 3-hour 0.90 10.47 512 2.04% 443 8.951 3-hour 0.90 8.06 512 1.57% 538.8 8.108 3-hour 0.90 7.30 512 1.43% 682.4 6.612 3-hour 0.90 5.95 512 1.16% 300 24-hour 0.40 4.65 91 5.11% 443 24-hour 0.40 3.58 91 3.93% 538.8 24-hour 0.40 3.24 91 3.56% 682.4 24-hour 0.40 2.64 91 2.90% 300 Annual 0.08 0.93 20 4.65% 443 Annual 0.08 0.72 20 3.60% 538.8 Annual 0.08 0.65 20 3.25% 682.4 Annual 0.08 0.53 20 2.65%



### The predicted maximum 3-hour, 24-hour and annual averaged concentrations from the Main Flare are 10.47, 4.65 and 0.93 μg/m 3 

### , respectively, located 1,097 meters from the flare stack. These maximum concentrations are approximate ly only 2.04%, 5.11% and 4.65% of the PSD Class II increments of 512, 91 and 20 μg/m 3 

### .for the 3-hour, 24-hou r and annual averaging periods, respectively. In addition, the maxi mum 3-hour, 24-hour and annua l concentrations are less than the Class II SILs of 25, 5 and 1 μg/m 3 

### , respectively.

### 7-5 7.2.2 National Ambient Air Qu ality Standards (NAAQS)



### Table 7-4 provides a comparis on of the estimated cumulativ e maximum 3-hour, 24-hour and annual averaged SO 2 

### impacts from the Main Flare, with a heat content of 300, 443, 538.8 and 682.4 BTU/SCF, to the corresponding SO 2 

### NAAQS. The modeled results are added to the cited background concentrations to arrive at th e estimated cumulative concentration for each averaging time, and the tota l value is compared to th e 3-hour, 24-hour and annual SO 2 

### NAAQS.

Table 7-4. Comparison of Modeled Cumulative SO 2 

### Impacts to the NAAQS

Max. Modeled Max. Adjusted Monitored Maximum National Heat One-Hour Modeled Background Cumulative Ambient Air Percent of Content Concentration Averaging Adjustment Concentr ation Concentration Concen tration Quality Std. NAAQS (BTU/SCF) (ug/m 3 ) Period Factor (ug/m 3 ) (ug/m 3 ) (ug/m 3 ) (ug/m 3 ) (%)

300 11.63 3-hour 0.90 10.47 136 146.47 1300 11.27% 443 8.951 3-hour 0.90 8.06 136 144.06 1300 11.08% 538.8 8.108 3-hour 0.90 7.30 136 143.30 1300 11.02% 682.4 6.612 3-hour 0.90 5.95 136 141.95 1300 10.92% 300 24-hour 0.40 4.65 39 43.65 365 11.96% 443 24-hour 0.40 3.58 39 42.58 365 11.67% 538.8 24-hour 0.40 3.24 39 42.24 365 11.57% 682.4 24-hour 0.40 2.64 39 41.64 365 11.41% 300 Annual 0.08 0.93 39 39.93 80 49.91% 443 Annual 0.08 0.72 39 39.72 80 49.65% 538.8 Annual 0.08 0.65 39 39.65 80 49.56% 682.4 Annual 0.08 0.53 39 39.53 80 49.41%



### The predicted maximum 3-hour, 24-hour and annual averaged concentrations from the Main Flare are 10.47, 4.65 and 0.93 μg/m 3 

### , respectively, located 1,097 meters from the flare stack.

These maximum concentrations added to the background concentrations of 136, 39 and 39 μg/m 3



### result in cumulative concentra tions of 11% to 12% of the 3-hour and 24-hour averaged NAAQS of 1300 and 365 μg/m 3 

### , respectively, and approximately 50% of the annual av eraged NAAQS of 80 μg/m 3



### .

### 7-6 7.3 CARBON MONOXIDE (CO)



### The Main Flare was modeled at the heat content scenarios of 300, 443, 538.8 and 682.4 BTU/SCF. The modeled impact concentrations from SCREEN3 were multiplied by the 1-hour and 8-hour averaging period adjust ment factors of 1.00 and 0.70, respectively. The maximum background 1-hour and 8-hour averaged CO c oncentration from Table 5-1 of 5,726 μg/m 3 

### is

cited as the value to add to the maximum modele d CO impacts from the Main Flare to obtain an estimate of cumulative impacts for comparison to the CO NAAQS. Note that the cited 8-hour background concentration has been assumed to also represent th e 1-hour background concentration since no specific 1-hour av eraged monitoring data was available.

7.3.1 National Ambient Air Qu ality Standards (NAAQS)



### Table 7-5 provides a co mparison of the estimated cumulati ve maximum 1-hour and 8-hour averaged CO impacts from the Main Flare, with a heat content of 300, 443, 538.8 and 682.4 BTU/SCF, to the corresponding CO NAAQS. Th e modeled results are added to the cited background concentrations to arrive at th e estimated cumulative concentration for each averaging time, and the total value is compared to the 1-hour and 8-hour CO NAAQS.

Table 7-5. Comparison of Modeled Cumula tive CO Impacts to the NAAQS

Max. Modeled Max. Adjusted Monitored Maximum National Heat One-Hour Modeled Background Cumulative Ambient Air Percent of Content Concentration Averaging Adjustment Concentr ation Concentration Concen tration Quality Std. NAAQS (BTU/SCF) (ug/m 3 ) Period Factor (ug/m 3 ) (ug/m 3 ) (ug/m 3 ) (ug/m 3 ) (%)

300 16.21 1-hour 1.00 16.21 5,726 5742.21 40,000 14.36% 443 18.43 1-hour 1.00 18.43 5,726 5744.43 40,000 14.36% 538.8 20.37 1-hour 1.00 20.37 5,726 5746.37 40,000 14.37% 682.4 21.04 1-hour 1.00 21.04 5,726 5747.04 40,000 14.37% 300 8-hour 0.70 11.35 5,726 5737.35 10,000 57.37% 443 8-hour 0.70 12.90 5,726 5738.90 10,000 57.39% 538.8 8-hour 0.70 14.26 5,726 5740.26 10,000 57.40% 682.4 8-hour 0.70 14.73 5,726 5740.73 10,000 57.41%

### 7-7 The predicted maximum 1-hour and 8-hour averaged concentrations from the Main Flare are 21.04 and 14.73 μg/m 3 

### , respectively, located 1,174 meters from the flare stack. These maximum

concentrations added to the bac kground concentrations of 5,726 μg/m 3 

### results in cumulative concentrations of 14.37% of the 1-hour and 57. 41% of the 8-hour averaged NAAQS of 40,000 and 10,000 μg/m 3 

### , respectively.

In addition, the maximum 1-hour and 8-hour av eraged concentrations of 21.04 and 14.73 μg/m 3



### are less than the Class II SILs of 2,000 and 500 μg/m 3 

### , respectively.

7.4 CLASS I AREA IMPACTS



### Modeled SCREEN3 impacts at receptors located 50 km. from the flare are used to provide the qualitative discussion of impacts on ambient air quality and air quality related values presented below. The selection of a receptor distance of 50 km. is based on regulatory guidance stating

that 50 km. is the furthest distance at whic h application of a near-field model is deemed appropriate.

SCREEN3 was used to estimate impacts at 50 km. fr om the flare with a unit emission rate of 1.0 gm/sec at each of the four eff ective release heights associated with the range of modeled flare gas BTU contents. Since the resultant impact is for a short-term averaging period of one hour or less, averaging period adjustment factors described for Class II area impacts are applied to qualitatively estimate impacts at Class I and sensi tive Class II areas located 50 km. or more from the McElmo Gas Compression Facility. The es timated maximum impact at 50 km. from the flare for a one-hour averaging period with a unit emission rate is 0.243 μg/m 3 

### . The nearest Class I areas are Mesa Verde National Park, Canyonlands National Park and Arches National

Park. The distances to these three Class I ar eas from the main flare are 60, 96 and 160 km., respectively.

7.4.1 Class I Increments



### The maximum modeled one-hour impact at 50 km . from the flare with a unit emission rate, adjusted for averaging period and using polluta nt-specific short-term and annualized emission rates, provides conservative estimates of Class I and sensitive Class II area impacts. Table 7-6

### 7-8 shows that maximum NO 2 

### and SO 2 

### impacts are well below applicable PSD Class I area increments even with assuming flare upset emi ssions and assessing impacts at 50 km. away. A print-out of the SCREEN3 model r un is included in Appendix E.

TABLE 7-6. CLASS I AREA AMBIENT AIR IMPACTS

Max. 1-hr. 3-Hour 24-Hour Annual Chi/Q Class I Class I Class I Impact 3-Hour Increment 24-H our Increment Annual Increment Pollutant (μg/m 3 ) (μg/m 3 ) (μg/m 3 ) (μg/m 3 ) (μg/m 3 ) (μg/m 3 ) (μg/m 3 )

NO 2 0.243 -- -- -- -- 0.0102 2.5

SO 2 0.243 2.0142 25.0 0.8952 5.0 0.0336 2.0



### 7.4.2 Visibility



### Since Mesa Verde National Park is the closest Class I area to the McElmo Gas Compression Facility, VISCREEN was used to estimate visibili ty impacts from the Main Flare. Since the

nearest distance of Mesa Verde to the Main Flar e is approximately 60 km., use of VISCREEN is appropriate given the closeness of this distance to the 50 km. range cited for near-field models. A print-out of the VISCREEN r un is presented in Appendix E.

Based on the results of the VISCREEN run, visib ility impacts at Mesa Verde National Park from the Main Flare are less than the Level I screening thresholds. These thresholds state that plumes resulting from the proposed action will not cause an hourly change in extinction ( ∆ E) greater than or equal to 2.0, or cause an absolute plume contrast (C p 

### ) greater than or equal to 0.05. Impacts at the more distant Class I areas would even be lower.

7.4.3 Deposition



### Sulfur (S) and nitrogen (N) deposition were c onservatively assessed by using the Level I screening methodology presented in the IWAQM Phase 1 document, which assumes that

concentrations of NO 2 

### and SO 2 

### are deposited as HNO 3 

### and SO 2 

### . This methodology assumes that

all NO x 

### is converted to HNO3. Ma ximum annual impacts of NO X 

### and SO 2 

### were predicted by SCREEN3 at 50 km. from the Main Flare by using the SCREEN3 model results, and the resulting NO x 

### impacts were then converted to HNO 3 

### . This approach provides a conservative

### 7-9 estimate of deposition, as SCREEN3 does not a ccount for any removal of mass from the plume (i.e., depositional settling) during transport to the Class I areas.

Resulting HNO 3 

### and SO 2 

### impacts were then multiplied by conservative depositional velocity rates for each pollutant to assess nitrate and su lfate deposition in Class I areas at least 50 km. away. Assumed depositional velocity rates are 0.05 m/s and 0.005 m/s for nitrogen and sulfur deposition, respectively. Initial estimates we re then multiplied by two to account for both wet and dry deposition. Estimated nitrate and su lfate deposition are pres ented in Table 7-7.

TABLE 7-7. CLASS I AREA DEPOSITION IMPACTS

NO 2 Conc. Nitrate Deposition SO 2 Conc. Sulfate Deposition Class I Area ( μ g/m 3 ) (kg/ha-yr) ( μ g/m 3 ) (kg/ha-yr)

Any Class I Area > 50 km. away 0.01364 0.58900 0.03355 0.10581



### These conservative estimates of deposition impact s are well below any threshold effects levels for soils and vegetation which typically st art at approximately 3.0 - 5.0 kg/ha-yr.

### 8-1 8.0 REFERENCES



### Baukal, Jr., C. (Ed.). (2001). The John Zink Combustion Handbook. C RC Press: New York.

Consent Decree, United States of America v. Mobil Exploration & Producing, U.S., Inc., DOJ Case No. 90-5-2-1-2237, filed June 8, 2005 in Un ited States District Court, District of

Utah.

U.S. Environmental Protection Agency, 2000. Co mpilation of Air Pollution Emissions Factors,

5 th 

### Edition, AP 42, Office of Air and Radia tion, Office of Air Quality Planning and Standards, Research Triangle Park, North Carolina.

U.S. Environmental Protection Agency (EPA) Electronic Bulletin Boar d, RACT/BACT/LAER Clearinghouse.

### APPENDIX A

EXXONMOBIL MCELMO CREEK OIL PRODUCTION UNIT

CONSENT DECREE

### Case 2:05-cv-00319-PGC Document 7 Filed 06/08/2005 Page 1 of 35

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### Case 2:05-cv-00319-PGC Document 7 Filed 06/08/2005 Page 35 of 35

### APPENDIX B

DERIVATION OF ESTIMATED PRE-PROJECT AND POST-PROJECT

ACTUAL AND POTENTIAL TO EMIT EMISSIONS

### B-1 

## Appendix B Flare Emission Calculatio n Methodology - McElmo Gas Compression Facility

Applicable Emission Factor Equations:

Nitrogen oxides (NO x ), Carbon Monoxide (CO), Particulate Matter (PM) and Lead (Pb) ER = V * GHV * (1000 SCF/kscf) * (MMBtu/10 6 Btu) * EF * (1 ton/2000 lb) ER = Pollutant Em issions, tons per year (tpy) V = Volume of Gas Flared, 10 3 scf per year (kscf/yr) GHV = Gross Heating Value of Gas Flared, Btu/SCF EF = Pollutant emission factor, lb/MMBTU

Table 13.5-1 (NO x and CO) and Table 1.4- 2 (PM and Pb) of AP-42

Volatile Organic Compounds (VOC) ER = V * (1000 SCF/kscf) * (lb-mole/ 380 SCF) * MW * WF VOC * (1 - (D EFF /100)) * (1 ton/2000 lb) ER = Pollutant Em issions, tons per year (tpy) V = Volume of Gas Flared, 10 3 scf per year (kscf/yr) MW = Molecular Weight of VOCs in Flared Gas, lb/lb-mole

WF VOC = Weight Fraction of VOCs in Flared Gas

D EFF = Percent Destruction E fficiency of Flare ==> 98.0 percent

Sulfur Dioxide (SO 2 ) ER = V * (1000 SCF/kscf) * (lb-mole/ 380 SCF) * MF H2S * MW SO2 * (D EFF /100) * (1 ton/2000 lb) ER = Pollutant Em issions, tons per year (tpy) V = Volume of Gas Flared, 10 3 scf per year (kscf/yr)

MF H2S = Molar Fraction of H 2 S in Flared Gas

MW SO2 = Molecular Weight of SO 2 , 64 lb/lb-mole

D EFF = Percent Destruction E fficiency of Flare ==> 98.0 percent



### Equation Inputs for Actual Emissions Parameter Pre-Project Post-Project Name Units (1996) (2005) (Updated 2008)

V kscf/yr 1,145,960 727,704 730,000 GHV Btu/SCF 751.1 490.0 610.6

MW SO2 lb/lb-mole 64.0 64.0 64.0

MW VOC lb/lb-mole 36.9 39.1 37.9

MF H2S unitless 0.00146 0.00049 0.0005

WF VOC unitless 0.165 0.116 0.126

Notes: Updated 2008 GHV based on aver age of 538.8 and 682.4 Btu/SCF, range of values from 2005 - 08 data; Updated 2008 WF VOC based on average of .1072 and .1446, range of values from 2005-08 data Updated 2008 MW VOC based on average of 37.264 and 38.535, range of values from 2005-08 data

### B-2 Actual Emission Estimates Pollutant Pre-Project Post-Project Name Units EF (lb/MMBtu) (1996) (2005) (Updated 2008)

NO X tpy 0.068 29.3 12.1 15.2 CO tpy 0.37 159.2 66.0 82.5

PM 10 tpy 0.00745 3.2 1.3 1.7

PM 2.5 tpy 0.00745 3.2 1.3 1.7

Pb tpy 4.90E-07 0.00021 0.000087 0.000109 VOC tpy -- 183.6 86.9 91.7

SO 2 tpy -- 138.1 29.4 30.1



### McElmo Flare Actual Emissions 2001 – 2005

Year Volume (kscf/yr) NO x (tpy) VOC (tpy) SO 2 (tpy) CO (tpy)

2001 500,591 7.47 41.97 24.03 33.27 2002 863,834 13.46 98.93 36.17 73.48 2003 891,972 13.97 108.66 46.38 71.24 2004 580,005 9.89 76.46 26.88 53.52 2005 727,703 12.10 90.60 29.20 66.00 891,972 (maximum) x 1. 2 (PTE factor) = 1,070,366 PTE Volume



### Equation Inputs for PTE Emissions Parameter Pre-Project Post-Project

Name Units (1996) (2005) (Updated 2008) V kscf/yr 1,145,960 1,070,366 1,070,366 GHV Btu/SCF 751.1 445.0 682.4

MW SO2 lb/lb-mole 64.0 64.0 64.0

MW VOC lb/lb-mole 36.9 38.5 37.3

MF H2S unitless 0.00146 0.00063 0.0005

WF VOC unitless 0.165 0.120 0.145

Notes: Updated 2008 GHV based on maximum va lue of 682.4 Btu/SCF from 2005 - 08 data; Updated 2008 WF VOC based on maximum value of .1446 from 2005-08 data Updated 2008 MW VOC based on 37.264 estimate with ma ximum Btu/SCF gas from 2005-08 data



### PTE Emission Estimates Pollutant Pre-Proj ect Post-Project Name Units EF (lb/MMBtu) (1996) (2005) (Updated 2008) NO X tpy 0.068 29.3 16.2 24.8 CO tpy 0.37 159.2 88.1 135.1

PM 10 tpy 0.00745 3.2 1.8 2.7

PM 2.5 tpy 0.00745 3.2 1.8 2.7 Pb tpy 4.90E-07 0.00021 0.00012 0.000179 VOC tpy -- 183.6 130.1 151.8

SO 2 tpy -- 138.1 55.7 44.2

### APPENDIX C

SCREEN3 MODELING INPU T AND OUTPUT RESULTS**10/07/05 19:01:54**  ***** SCREEN3 MODEL RUN ***** ***** VERSION DATED 96043 *****

**NOX - McELMO CREEK MAIN FLARE - 618.104 SCF/HR; 300 BTU/SCF**

**SIMPLE TERRAIN INPUTS: SOURCE TYPE = FLARE**  **EMISSION RATE (G/S) = 1.50000 FLARE STACK HEIGHT (M) = 59.4500**  **TOT HEAT RLS (CAL/S) = .129887E+08 RECEPTOR HEIGHT (M) = .0000**  **URBAN/RURAL OPTION = RURAL EFF RELEASE HEIGHT (M) = 70.9117**  **BUILDING HEIGHT (M) = .0000 MIN HORIZ BLDG DIM (M) = .0000**  **MAX HORIZ BLDG DIM (M) = .0000**

**THE REGULATORY (DEFAULT) MIXING HEIGHT OPTION WAS SELECTED. THE REGULATORY (DEFAULT) ANEMOMETER HEIGHT OF 10.0 METERS WAS ENTERED.** 

**BUOY. FLUX = 215.357 M**4/S**3; MOM. FLUX = 131.320 M**4/S**2.**

***** FULL METEOROLOGY *****

************************************** ***** SCREEN AUTOMATED DISTANCES ***** **************************************

***** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES *****

**DIST CONC U10M USTK MIX HT PLUME SIGMA SIGMA (M) (UG/M** 3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DWASH**

**------- ---------- ---- ----- ----- ------ ------ ------ ------ ----- 200. .1976E-03 5 1.0 2.0 10000.0 212.67 42.14 40.98 NO**  **300. .2504E-03 5 1.0 2.0 10000.0 212.67 43.89 41.43 NO 400. .1994E-02 1 3.0 3.4 960.0 353.43 102.30 83.27 NO**  **500. .9364E-01 1 3.0 3.4 960.0 353.43 123.67 116.05 NO 600. .5748 1 3.0 3.4 960.0 353.43 144.45 164.03 NO**  **700. 1.071 1 3.0 3.4 960.0 353.43 164.74 222.37 NO 800. 1.236 1 3.0 3.4 960.0 353.43 184.62 291.21 NO**  **900. 1.570 1 1.5 1.7 636.9 635.95 241.27 392.31 NO 1000. 1.831 1 1.5 1.7 636.9 635.95 262.53 480.98 NO**  **1100. 1.893 1 1.5 1.7 636.9 635.95 278.55 578.29 NO 1200. 1.849 1 1.5 1.7 636.9 635.95 293.46 686.83 NO**  **1300. 1.769 1 1.5 1.7 636.9 635.95 308.54 807.14 NO 1400. 1.687 1 1.5 1.7 636.9 635.95 323.75 939.12 NO**  **1500. 1.611 1 1.5 1.7 636.9 635.95 339.05 1082.70 NO 1600. 1.541 1 1.5 1.7 636.9 635.95 354.42 1237.88 NO**  **1700. 1.477 1 1.5 1.7 636.9 635.95 369.84 1404.65 NO 1800. 1.417 1 1.5 1.7 636.9 635.95 385.28 1583.04 NO**  **1900. 1.363 1 1.5 1.7 636.9 635.95 400.74 1773.09 NO 2000. 1.312 1 1.5 1.7 636.9 635.95 416.20 1974.82 NO**  **2100. 1.265 1 1.5 1.7 636.9 635.95 431.66 2188.30 NO 2200. 1.221 1 1.5 1.7 636.9 635.95 447.11 2413.56 NO** **2300. 1.181 1 1.5 1.7 636.9 635.95 462.53 2650.65 NO 2400. 1.143 1 1.5 1.7 636.9 635.95 477.94 2899.62 NO**  **2500. 1.107 1 1.5 1.7 636.9 635.95 493.32 3160.53 NO 2600. 1.074 1 1.5 1.7 636.9 635.95 508.66 3433.41 NO**  **2700. 1.042 1 1.5 1.7 636.9 635.95 523.98 3718.32 NO 2800. 1.013 1 1.5 1.7 636.9 635.95 539.26 4015.30 NO**  **2900. .9848 1 1.5 1.7 636.9 635.95 554.51 4324.41 NO 3000. .9585 1 1.5 1.7 636.9 635.95 569.72 4645.68 NO**  **3500. .9357 2 1.5 1.7 636.9 635.95 495.84 461.21 NO 4000. .9215 2 1.5 1.7 636.9 635.95 551.47 525.60 NO**  **4500. .8746 2 1.5 1.7 636.9 635.95 606.70 591.64 NO 5000. .8172 2 1.5 1.7 636.9 635.95 661.47 659.02 NO** 

**MAXIMUM 1-HR CONCENTRATION AT OR BEYOND 200. M: 1097. 1.893 1 1.5 1.7 636.9 635.95 277.95 574.19 NO** 

**DWASH= MEANS NO CALC MADE (CONC = 0.0) DWASH=NO MEANS NO BUILDING DOWNWASH USED**  **DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED**  **DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB**

************************************************ *** SUMMARY OF TERRAIN HEIGHTS ENTERED FOR *** *** SIMPLE ELEVATED TERRAIN PROCEDURE *** ************************************************

**TERRAIN DISTANCE RANGE (M) HT (M) MINIMUM MAXIMUM** 

**------- -------- -------- 0. 200. 5000.** 

******************************************* ***** SUMMARY OF SCREEN MODEL RESULTS ***** *******************************************

**CALCULATION MAX CONC DIST TO TERRAIN PROCEDURE (UG/M** 3) MAX (M) HT (M)**

**-------------- ----------- ------- ------- SIMPLE TERRAIN 1.893 1097. 0.** 

*******************************************************   REMEMBER TO INCLUDE BACKGROUND CONCENTRATIONS ** ** *********************************************************10/07/05 18:59:19**  ***** SCREEN3 MODEL RUN ***** ***** VERSION DATED 96043 *****

**NOx - McELMO CREEK MAIN FLARE - 618.104 SCF/HR; 443 BTU/SCF**

**SIMPLE TERRAIN INPUTS: SOURCE TYPE = FLARE**  **EMISSION RATE (G/S) = 2.21000 FLARE STACK HEIGHT (M) = 59.4500**  **TOT HEAT RLS (CAL/S) = .191799E+08 RECEPTOR HEIGHT (M) = .0000**  **URBAN/RURAL OPTION = RURAL EFF RELEASE HEIGHT (M) = 73.2591**  **BUILDING HEIGHT (M) = .0000 MIN HORIZ BLDG DIM (M) = .0000**  **MAX HORIZ BLDG DIM (M) = .0000**

**THE REGULATORY (DEFAULT) MIXING HEIGHT OPTION WAS SELECTED. THE REGULATORY (DEFAULT) ANEMOMETER HEIGHT OF 10.0 METERS WAS ENTERED.** 

**BUOY. FLUX = 318.009 M**4/S**3; MOM. FLUX = 193.915 M**4/S**2.**

***** FULL METEOROLOGY *****

************************************** ***** SCREEN AUTOMATED DISTANCES ***** **************************************

***** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES *****

**DIST CONC U10M USTK MIX HT PLUME SIGMA SIGMA (M) (UG/M** 3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DWASH**

**------- ---------- ---- ----- ----- ------ ------ ------ ------ ----- 200. .4666E-03 5 1.0 2.0 10000.0 234.08 47.40 46.37 NO**  **300. .5548E-03 5 1.0 2.0 10000.0 234.08 48.96 46.76 NO 400. .6661E-03 5 1.0 2.0 10000.0 234.08 50.95 47.20 NO**  **500. .2049E-01 1 3.0 3.4 960.0 429.40 126.59 119.17 NO 600. .3019 1 3.0 3.4 960.0 429.40 147.64 166.85 NO**  **700. .8718 1 3.0 3.4 960.0 429.40 168.18 224.94 NO 800. 1.266 1 3.0 3.4 960.0 429.40 188.30 293.55 NO**  **900. 1.755 1 2.0 2.3 640.0 607.47 228.42 384.54 NO 1000. 2.089 1 2.0 2.3 640.0 607.47 248.95 473.71 NO**  **1100. 2.143 1 2.0 2.3 640.0 607.47 269.15 573.82 NO 1200. 2.061 1 2.0 2.3 640.0 607.47 288.71 684.81 NO**  **1300. 1.969 1 2.0 2.3 640.0 607.47 304.03 805.43 NO 1400. 1.876 1 2.0 2.3 640.0 607.47 319.45 937.65 NO**  **1500. 1.800 1 1.5 1.7 786.5 785.55 360.99 1089.77 NO 1600. 1.731 1 1.5 1.7 786.5 785.55 375.46 1244.06 NO**  **1700. 1.667 1 1.5 1.7 786.5 785.55 390.04 1410.10 NO 1800. 1.606 1 1.5 1.7 786.5 785.55 404.72 1587.88 NO**  **1900. 1.550 1 1.5 1.7 786.5 785.55 419.46 1777.41 NO 2000. 1.497 1 1.5 1.7 786.5 785.55 434.26 1978.71 NO**  **2100. 1.447 1 1.5 1.7 786.5 785.55 449.09 2191.81 NO 2200. 1.401 1 1.5 1.7 786.5 785.55 463.96 2416.74 NO** **2300. 1.358 1 1.5 1.7 786.5 785.55 478.84 2653.55 NO 2400. 1.317 1 1.5 1.7 786.5 785.55 493.74 2902.27 NO**  **2500. 1.278 1 1.5 1.7 786.5 785.55 508.64 3162.96 NO 2600. 1.242 1 1.5 1.7 786.5 785.55 523.54 3435.64 NO**  **2700. 1.207 1 1.5 1.7 786.5 785.55 538.43 3720.38 NO 2800. 1.175 1 1.5 1.7 786.5 785.55 553.32 4017.22 NO**  **2900. 1.144 1 1.5 1.7 786.5 785.55 568.18 4326.19 NO 3000. 1.115 1 1.5 1.7 786.5 785.55 583.04 4647.34 NO**  **3500. 1.024 2 2.0 2.3 640.0 607.47 493.05 458.20 NO 4000. 1.012 2 2.0 2.3 640.0 607.47 548.96 522.97 NO**  **4500. .9615 2 2.0 2.3 640.0 607.47 604.41 589.30 NO 5000. .9124 2 1.5 1.7 786.5 785.55 672.98 670.57 NO** 

**MAXIMUM 1-HR CONCENTRATION AT OR BEYOND 200. M: 1075. 2.148 1 2.0 2.3 640.0 607.47 263.93 546.73 NO** 

**DWASH= MEANS NO CALC MADE (CONC = 0.0) DWASH=NO MEANS NO BUILDING DOWNWASH USED**  **DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED**  **DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB**

************************************************ *** SUMMARY OF TERRAIN HEIGHTS ENTERED FOR *** *** SIMPLE ELEVATED TERRAIN PROCEDURE *** ************************************************

**TERRAIN DISTANCE RANGE (M) HT (M) MINIMUM MAXIMUM** 

**------- -------- -------- 0. 200. 5000.** 

******************************************* ***** SUMMARY OF SCREEN MODEL RESULTS ***** *******************************************

**CALCULATION MAX CONC DIST TO TERRAIN PROCEDURE (UG/M** 3) MAX (M) HT (M)**

**-------------- ----------- ------- ------- SIMPLE TERRAIN 2.148 1075. 0.** 

*******************************************************   REMEMBER TO INCLUDE BACKGROUND CONCENTRATIONS ** ** *********************************************************1 03/10/08**  **12:23:31** ***** SCREEN3 MODEL RUN ***** ***** VERSION DATED 96043 *****

**NOx McELMO CREEK MAIN FLARE - 618104 SCF/HR; 538.8 BTU**

**SIMPLE TERRAIN INPUTS: SOURCE TYPE = FLARE**  **EMISSION RATE (G/S) = 2.69000 FLARE STACK HEIGHT (M) = 59.4500**  **TOT HEAT RLS (CAL/S) = .233276E+08**

**RECEPTOR HEIGHT (M) = .0000 URBAN/RURAL OPTION = RURAL**  **EFF RELEASE HEIGHT (M) = 74.6137 BUILDING HEIGHT (M) = .0000**  **MIN HORIZ BLDG DIM (M) = .0000 MAX HORIZ BLDG DIM (M) = .0000** 

**THE REGULATORY (DEFAULT) MIXING HEIGHT OPTION WAS SELECTED. THE REGULATORY (DEFAULT) ANEMOMETER HEIGHT OF 10.0 METERS WAS ENTERED.** 

**BUOY. FLUX = 386.779 M**4/S**3; MOM. FLUX = 235.850 M**4/S**2.**

***** FULL METEOROLOGY *****

************************************** ***** SCREEN AUTOMATED DISTANCES ***** **************************************

***** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES *****

**DIST CONC U10M USTK MIX HT PLUME SIGMA SIGMA (M) (UG/M** 3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DWASH**

**------- ---------- ---- ----- ----- ------ ------ ------ ------ ----- 200. .6884E-03 5 1.0 2.0 10000.0 245.91 50.30 49.34 NO**  **300. .7985E-03 5 1.0 2.0 10000.0 245.91 51.78 49.71 NO 400. .9341E-03 5 1.0 2.0 10000.0 245.91 53.66 50.12 NO**  **500. .7289E-02 1 3.0 3.5 960.0 474.63 128.33 121.01 NO 600. .1865 1 3.0 3.5 960.0 474.63 149.55 168.54 NO**  **700. .7154 1 3.0 3.5 960.0 474.63 170.23 226.48 NO 800. 1.209 1 3.0 3.5 960.0 474.63 190.49 294.96 NO**  **900. 1.799 1 2.0 2.3 675.6 674.64 233.15 387.37 NO 1000. 2.250 1 2.0 2.3 675.6 674.64 253.95 476.35 NO**  **1100. 2.376 1 2.0 2.3 675.6 674.64 274.40 576.30 NO 1200. 2.314 1 2.0 2.3 675.6 674.64 294.53 687.29 NO**  **1300. 2.194 1 2.0 2.3 675.6 674.64 313.89 809.20 NO 1400. 2.098 1 2.0 2.3 675.6 674.64 328.85 940.89 NO**  **1500. 2.006 1 2.0 2.3 675.6 674.64 343.93 1084.24 NO 1600. 1.921 1 2.0 2.3 675.6 674.64 359.09 1239.22 NO**  **1700. 1.843 1 2.0 2.3 675.6 674.64 374.31 1405.83 NO 1800. 1.771 1 2.0 2.3 675.6 674.64 389.58 1584.09 NO**  **1900. 1.704 1 2.0 2.3 675.6 674.64 404.87 1774.02 NO 2000. 1.642 1 2.0 2.3 675.6 674.64 420.18 1975.67 NO**  **2100. 1.584 1 2.0 2.3 675.6 674.64 435.50 2189.06 NO 2200. 1.530 1 2.0 2.3 675.6 674.64 450.81 2414.25 NO**  **2300. 1.480 1 2.0 2.3 675.6 674.64 466.12 2651.28 NO 2400. 1.433 1 2.0 2.3 675.6 674.64 481.41 2900.20 NO**  **2500. 1.389 1 2.0 2.3 675.6 674.64 496.68 3161.05 NO 2600. 1.348 1 2.0 2.3 675.6 674.64 511.92 3433.89 NO**  **2700. 1.309 1 2.0 2.3 675.6 674.64 527.15 3718.77 NO 2800. 1.272 1 2.0 2.3 675.6 674.64 542.34 4015.72 NO**  **2900. 1.238 1 2.0 2.3 675.6 674.64 557.50 4324.79 NO 3000. 1.205 1 2.0 2.3 675.6 674.64 572.63 4646.04 NO** **2 MAXIMUM 1-HR CONCENTRATION AT OR BEYOND 200. M:**  **1104. 2.376 1 2.0 2.3 675.6 674.64 275.01 579.47 NO**

**DWASH= MEANS NO CALC MADE (CONC = 0.0) DWASH=NO MEANS NO BUILDING DOWNWASH USED**  **DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED**  **DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB**

************************************* ***** SCREEN DISCRETE DISTANCES ***** *************************************

***** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES *****

**DIST CONC U10M USTK MIX HT PLUME SIGMA SIGMA (M) (UG/M** 3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DWASH**

**------- ---------- ---- ----- ----- ------ ------ ------ ------ ----- 3100. 1.174 1 2.0 2.3 675.6 674.64 587.73 4979.50 NO**  **3200. 1.145 1 2.0 2.3 675.6 674.64 602.79 5000.00 NO 3300. 1.117 1 2.0 2.3 675.6 674.64 617.82 5000.00 NO**  **3400. 1.104 2 2.0 2.3 675.6 674.64 488.10 452.26 NO 3500. 1.115 2 2.0 2.3 675.6 674.64 499.19 464.80 NO**  **3600. 1.122 2 2.0 2.3 675.6 674.64 510.27 477.44 NO 3700. 1.126 2 2.0 2.3 675.6 674.64 521.34 490.15 NO**  **3800. 1.128 2 2.0 2.3 675.6 674.64 532.40 502.95 NO 3900. 1.127 2 2.0 2.3 675.6 674.64 543.45 515.82 NO**  **4000. 1.123 2 2.0 2.3 675.6 674.64 554.48 528.76 NO 4100. 1.118 2 2.0 2.3 675.6 674.64 565.50 541.77 NO**  **4200. 1.111 2 2.0 2.3 675.6 674.64 576.51 554.85 NO 4300. 1.103 2 2.0 2.3 675.6 674.64 587.50 567.99 NO**  **4400. 1.093 2 2.0 2.3 675.6 674.64 598.47 581.19 NO 4500. 1.082 2 2.0 2.3 675.6 674.64 609.43 594.45 NO**  **4600. 1.071 2 2.0 2.3 675.6 674.64 620.38 607.77 NO 4700. 1.059 2 2.0 2.3 675.6 674.64 631.30 621.13 NO**  **4800. 1.047 2 2.0 2.3 675.6 674.64 642.21 634.55 NO 4900. 1.034 2 2.0 2.3 675.6 674.64 653.11 648.02 NO**  **5000. 1.021 2 2.0 2.3 675.6 674.64 663.98 661.54 NO**

**DWASH= MEANS NO CALC MADE (CONC = 0.0) DWASH=NO MEANS NO BUILDING DOWNWASH USED**  **DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED**  **DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB**

************************************************ *** SUMMARY OF TERRAIN HEIGHTS ENTERED FOR *** *** SIMPLE ELEVATED TERRAIN PROCEDURE *** ************************************************

**TERRAIN DISTANCE RANGE (M) HT (M) MINIMUM MAXIMUM** 

**------- -------- -------- 0. 200. 3000.**  **0. 3100. -- 0. 3200. --**  **0. 3300. -- 0. 3400. --**  **0. 3500. -- 0. 3600. --**  **0. 3700. -- 0. 3800. --**  **0. 3900. -- 0. 4000. --**  **0. 4100. -- 0. 4200. --** **3 0. 4300. --**  **0. 4400. -- 0. 4500. --**  **0. 4600. -- 0. 4700. --**  **0. 4800. -- 0. 4900. --**  **0. 5000. --**

******************************************* ***** SUMMARY OF SCREEN MODEL RESULTS ***** *******************************************

**CALCULATION MAX CONC DIST TO TERRAIN PROCEDURE (UG/M** 3) MAX (M) HT (M)**

**-------------- ----------- ------- ------- SIMPLE TERRAIN 2.376 1104. 0.** 

*******************************************************   REMEMBER TO INCLUDE BACKGROUND CONCENTRATIONS ** ** *********************************************************1 03/10/08**  **12:34:04** ***** SCREEN3 MODEL RUN ***** ***** VERSION DATED 96043 *****

**NOx - McELMO CREEK MAIN FLARE - 618104 SCF/HR; 682.4 BTU**

**SIMPLE TERRAIN INPUTS: SOURCE TYPE = FLARE**  **EMISSION RATE (G/S) = 3.41000 FLARE STACK HEIGHT (M) = 59.4500**  **TOT HEAT RLS (CAL/S) = .295449E+08**

**RECEPTOR HEIGHT (M) = .0000 URBAN/RURAL OPTION = RURAL**  **EFF RELEASE HEIGHT (M) = 76.4268 BUILDING HEIGHT (M) = .0000**  **MIN HORIZ BLDG DIM (M) = .0000 MAX HORIZ BLDG DIM (M) = .0000** 

**THE REGULATORY (DEFAULT) MIXING HEIGHT OPTION WAS SELECTED. THE REGULATORY (DEFAULT) ANEMOMETER HEIGHT OF 10.0 METERS WAS ENTERED.** 

**BUOY. FLUX = 489.864 M**4/S**3; MOM. FLUX = 298.709 M**4/S**2.**

***** FULL METEOROLOGY *****

************************************** ***** SCREEN AUTOMATED DISTANCES ***** **************************************

***** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES *****

**DIST CONC U10M USTK MIX HT PLUME SIGMA SIGMA (M) (UG/M** 3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DWASH**

**------- ---------- ---- ----- ----- ------ ------ ------ ------ ----- 200. .1062E-02 5 1.0 2.0 10000.0 261.24 54.07 53.17 NO**  **300. .1201E-02 5 1.0 2.0 10000.0 261.24 55.44 53.52 NO 400. .1369E-02 5 1.0 2.0 10000.0 261.24 57.21 53.90 NO**  **500. .1579E-02 5 1.0 2.0 10000.0 261.24 59.31 54.33 NO 600. .8705E-01 1 3.0 3.5 960.0 536.60 152.15 170.85 NO**  **700. .5045 1 3.0 3.5 960.0 536.60 173.04 228.59 NO 800. 1.067 1 3.0 3.5 960.0 536.60 193.49 296.90 NO**  **900. 1.465 1 2.0 2.3 767.7 766.68 239.56 391.26 NO 1000. 2.094 1 2.0 2.3 767.7 766.68 260.73 480.00 NO**  **1100. 2.402 1 2.0 2.3 767.7 766.68 281.52 579.73 NO 1200. 2.451 1 2.0 2.3 767.7 766.68 301.99 690.52 NO**  **1300. 2.366 1 2.0 2.3 767.7 766.68 322.16 812.44 NO 1400. 2.244 1 2.0 2.3 767.7 766.68 342.05 945.58 NO**  **1500. 2.149 1 2.0 2.3 767.7 766.68 357.48 1088.61 NO 1600. 2.065 1 2.0 2.3 767.7 766.68 372.09 1243.05 NO**  **1700. 1.987 1 2.0 2.3 767.7 766.68 386.80 1409.21 NO 1800. 1.914 1 2.0 2.3 767.7 766.68 401.59 1587.09 NO**  **1900. 1.845 1 2.0 2.3 767.7 766.68 416.44 1776.70 NO 2000. 1.782 1 2.0 2.3 767.7 766.68 431.34 1978.07 NO**  **2100. 1.722 1 2.0 2.3 767.7 766.68 446.28 2191.23 NO 2200. 1.666 1 2.0 2.3 767.7 766.68 461.23 2416.22 NO**  **2300. 1.614 1 2.0 2.3 767.7 766.68 476.20 2653.07 NO 2400. 1.565 1 2.0 2.3 767.7 766.68 491.18 2901.84 NO**  **2500. 1.518 1 2.0 2.3 767.7 766.68 506.15 3162.56 NO 2600. 1.475 1 2.0 2.3 767.7 766.68 521.12 3435.28 NO**  **2700. 1.433 1 2.0 2.3 767.7 766.68 536.08 3720.04 NO 2**  **2800. 1.395 1 2.0 2.3 767.7 766.68 551.03 4016.90 NO 2900. 1.358 1 2.0 2.3 767.7 766.68 565.96 4325.89 NO**  **3000. 1.323 1 2.0 2.3 767.7 766.68 580.87 4647.06 NO**

**MAXIMUM 1-HR CONCENTRATION AT OR BEYOND 200. M: 1174. 2.456 1 2.0 2.3 767.7 766.68 296.49 659.51 NO** 

**DWASH= MEANS NO CALC MADE (CONC = 0.0) DWASH=NO MEANS NO BUILDING DOWNWASH USED**  **DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED**  **DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB**

************************************* ***** SCREEN DISCRETE DISTANCES ***** *************************************

***** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES *****

**DIST CONC U10M USTK MIX HT PLUME SIGMA SIGMA (M) (UG/M** 3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DWASH**

**------- ---------- ---- ----- ----- ------ ------ ------ ------ ----- 3100. 1.290 1 2.0 2.3 767.7 766.68 595.76 4980.46 NO**  **3200. 1.258 1 2.0 2.3 767.7 766.68 610.62 5000.00 NO 3300. 1.229 1 2.0 2.3 767.7 766.68 625.46 5000.00 NO**  **3400. 1.200 1 2.0 2.3 767.7 766.68 640.27 5000.00 NO 3500. 1.173 1 2.0 2.3 767.7 766.68 655.06 5000.00 NO**  **3600. 1.147 1 2.0 2.3 767.7 766.68 669.81 5000.00 NO 3700. 1.123 1 2.0 2.3 767.7 766.68 684.54 5000.00 NO**  **3800. 1.105 2 2.0 2.3 767.7 766.68 541.25 512.31 NO 3900. 1.115 2 2.0 2.3 767.7 766.68 552.12 524.95 NO**  **4000. 1.123 2 2.0 2.3 767.7 766.68 562.99 537.67 NO 4100. 1.127 2 2.0 2.3 767.7 766.68 573.84 550.47 NO**  **4200. 1.130 2 2.0 2.3 767.7 766.68 584.69 563.35 NO 4300. 1.130 2 2.0 2.3 767.7 766.68 595.53 576.30 NO**  **4400. 1.129 2 2.0 2.3 767.7 766.68 606.36 589.31 NO 4500. 1.126 2 2.0 2.3 767.7 766.68 617.18 602.39 NO**  **4600. 1.121 2 2.0 2.3 767.7 766.68 627.99 615.53 NO 4700. 1.115 2 2.0 2.3 767.7 766.68 638.79 628.74 NO**  **4800. 1.108 2 2.0 2.3 767.7 766.68 649.57 642.00 NO 4900. 1.100 2 2.0 2.3 767.7 766.68 660.34 655.31 NO**  **5000. 1.091 2 2.0 2.3 767.7 766.68 671.10 668.68 NO**

**DWASH= MEANS NO CALC MADE (CONC = 0.0) DWASH=NO MEANS NO BUILDING DOWNWASH USED**  **DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED**  **DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB**

************************************************ *** SUMMARY OF TERRAIN HEIGHTS ENTERED FOR *** *** SIMPLE ELEVATED TERRAIN PROCEDURE *** ************************************************

**TERRAIN DISTANCE RANGE (M) HT (M) MINIMUM MAXIMUM** 

**------- -------- -------- 0. 200. 3000.**  **0. 3100. -- 0. 3200. --**  **0. 3300. -- 0. 3400. --**  **0. 3500. -- 3**  **0. 3600. -- 0. 3700. --**  **0. 3800. -- 0. 3900. --**  **0. 4000. -- 0. 4100. --**  **0. 4200. -- 0. 4300. --**  **0. 4400. -- 0. 4500. --**  **0. 4600. -- 0. 4700. --**  **0. 4800. -- 0. 4900. --**  **0. 5000. --**

******************************************* ***** SUMMARY OF SCREEN MODEL RESULTS ***** *******************************************

**CALCULATION MAX CONC DIST TO TERRAIN PROCEDURE (UG/M** 3) MAX (M) HT (M)**

**-------------- ----------- ------- ------- SIMPLE TERRAIN 2.456 1174. 0.** 

*******************************************************   REMEMBER TO INCLUDE BACKGROUND CONCENTRATIONS ** ** *********************************************************10/07/05 18:48:51**  ***** SCREEN3 MODEL RUN ***** ***** VERSION DATED 96043 *****

**CO - McELMO CREEK MAIN FLARE - 618.104 SCF/HR; 300 BTU/SCF**

**SIMPLE TERRAIN INPUTS: SOURCE TYPE = FLARE**  **EMISSION RATE (G/S) = 12.8400 FLARE STACK HEIGHT (M) = 59.4500**  **TOT HEAT RLS (CAL/S) = .129887E+08 RECEPTOR HEIGHT (M) = .0000**  **URBAN/RURAL OPTION = RURAL EFF RELEASE HEIGHT (M) = 70.9117**  **BUILDING HEIGHT (M) = .0000 MIN HORIZ BLDG DIM (M) = .0000**  **MAX HORIZ BLDG DIM (M) = .0000**

**THE REGULATORY (DEFAULT) MIXING HEIGHT OPTION WAS SELECTED. THE REGULATORY (DEFAULT) ANEMOMETER HEIGHT OF 10.0 METERS WAS ENTERED.** 

**BUOY. FLUX = 215.357 M**4/S**3; MOM. FLUX = 131.320 M**4/S**2.**

***** FULL METEOROLOGY *****

************************************** ***** SCREEN AUTOMATED DISTANCES ***** **************************************

***** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES *****

**DIST CONC U10M USTK MIX HT PLUME SIGMA SIGMA (M) (UG/M** 3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DWASH**

**------- ---------- ---- ----- ----- ------ ------ ------ ------ ----- 200. .1691E-02 5 1.0 2.0 10000.0 212.67 42.14 40.98 NO**  **300. .2143E-02 5 1.0 2.0 10000.0 212.67 43.89 41.43 NO 400. .1707E-01 1 3.0 3.4 960.0 353.43 102.30 83.27 NO**  **500. .8015 1 3.0 3.4 960.0 353.43 123.67 116.05 NO 600. 4.920 1 3.0 3.4 960.0 353.43 144.45 164.03 NO**  **700. 9.169 1 3.0 3.4 960.0 353.43 164.74 222.37 NO 800. 10.58 1 3.0 3.4 960.0 353.43 184.62 291.21 NO**  **900. 13.44 1 1.5 1.7 636.9 635.95 241.27 392.31 NO 1000. 15.67 1 1.5 1.7 636.9 635.95 262.53 480.98 NO**  **1100. 16.21 1 1.5 1.7 636.9 635.95 278.55 578.29 NO 1200. 15.83 1 1.5 1.7 636.9 635.95 293.46 686.83 NO**  **1300. 15.14 1 1.5 1.7 636.9 635.95 308.54 807.14 NO 1400. 14.44 1 1.5 1.7 636.9 635.95 323.75 939.12 NO**  **1500. 13.79 1 1.5 1.7 636.9 635.95 339.05 1082.70 NO 1600. 13.19 1 1.5 1.7 636.9 635.95 354.42 1237.88 NO**  **1700. 12.64 1 1.5 1.7 636.9 635.95 369.84 1404.65 NO 1800. 12.13 1 1.5 1.7 636.9 635.95 385.28 1583.04 NO**  **1900. 11.66 1 1.5 1.7 636.9 635.95 400.74 1773.09 NO 2000. 11.23 1 1.5 1.7 636.9 635.95 416.20 1974.82 NO**  **2100. 10.83 1 1.5 1.7 636.9 635.95 431.66 2188.30 NO 2200. 10.45 1 1.5 1.7 636.9 635.95 447.11 2413.56 NO** **2300. 10.11 1 1.5 1.7 636.9 635.95 462.53 2650.65 NO 2400. 9.780 1 1.5 1.7 636.9 635.95 477.94 2899.62 NO**  **2500. 9.476 1 1.5 1.7 636.9 635.95 493.32 3160.53 NO 2600. 9.190 1 1.5 1.7 636.9 635.95 508.66 3433.41 NO**  **2700. 8.921 1 1.5 1.7 636.9 635.95 523.98 3718.32 NO 2800. 8.668 1 1.5 1.7 636.9 635.95 539.26 4015.30 NO**  **2900. 8.430 1 1.5 1.7 636.9 635.95 554.51 4324.41 NO 3000. 8.205 1 1.5 1.7 636.9 635.95 569.72 4645.68 NO**  **3500. 8.010 2 1.5 1.7 636.9 635.95 495.84 461.21 NO 4000. 7.888 2 1.5 1.7 636.9 635.95 551.47 525.60 NO**  **4500. 7.487 2 1.5 1.7 636.9 635.95 606.70 591.64 NO 5000. 6.995 2 1.5 1.7 636.9 635.95 661.47 659.02 NO** 

**MAXIMUM 1-HR CONCENTRATION AT OR BEYOND 200. M: 1097. 16.21 1 1.5 1.7 636.9 635.95 277.95 574.19 NO** 

**DWASH= MEANS NO CALC MADE (CONC = 0.0) DWASH=NO MEANS NO BUILDING DOWNWASH USED**  **DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED**  **DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB**

************************************************ *** SUMMARY OF TERRAIN HEIGHTS ENTERED FOR *** *** SIMPLE ELEVATED TERRAIN PROCEDURE *** ************************************************

**TERRAIN DISTANCE RANGE (M) HT (M) MINIMUM MAXIMUM** 

**------- -------- -------- 0. 200. 5000.** 

******************************************* ***** SUMMARY OF SCREEN MODEL RESULTS ***** *******************************************

**CALCULATION MAX CONC DIST TO TERRAIN PROCEDURE (UG/M** 3) MAX (M) HT (M)**

**-------------- ----------- ------- ------- SIMPLE TERRAIN 16.21 1097. 0.** 

*******************************************************   REMEMBER TO INCLUDE BACKGROUND CONCENTRATIONS ** ** *********************************************************11/07/05 16:19:36**  ***** SCREEN3 MODEL RUN ***** ***** VERSION DATED 96043 *****

**CO - McELMO CREEK MAIN FLARE - 618.104 SCF/HR; 443 BTU/SCF**

**SIMPLE TERRAIN INPUTS: SOURCE TYPE = FLARE**  **EMISSION RATE (G/S) = 18.9600 FLARE STACK HEIGHT (M) = 59.4500**  **TOT HEAT RLS (CAL/S) = .191799E+08 RECEPTOR HEIGHT (M) = .0000**  **URBAN/RURAL OPTION = RURAL EFF RELEASE HEIGHT (M) = 73.2591**  **BUILDING HEIGHT (M) = .0000 MIN HORIZ BLDG DIM (M) = .0000**  **MAX HORIZ BLDG DIM (M) = .0000**

**THE REGULATORY (DEFAULT) MIXING HEIGHT OPTION WAS SELECTED. THE REGULATORY (DEFAULT) ANEMOMETER HEIGHT OF 10.0 METERS WAS ENTERED.** 

**BUOY. FLUX = 318.009 M**4/S**3; MOM. FLUX = 193.915 M**4/S**2.**

***** FULL METEOROLOGY *****

************************************** ***** SCREEN AUTOMATED DISTANCES ***** **************************************

***** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES *****

**DIST CONC U10M USTK MIX HT PLUME SIGMA SIGMA (M) (UG/M** 3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DWASH**

**------- ---------- ---- ----- ----- ------ ------ ------ ------ ----- 200. .4003E-02 5 1.0 2.0 10000.0 234.08 47.40 46.37 NO**  **300. .4760E-02 5 1.0 2.0 10000.0 234.08 48.96 46.76 NO 400. .5715E-02 5 1.0 2.0 10000.0 234.08 50.95 47.20 NO**  **500. .1758 1 3.0 3.4 960.0 429.40 126.59 119.17 NO 600. 2.590 1 3.0 3.4 960.0 429.40 147.64 166.85 NO**  **700. 7.479 1 3.0 3.4 960.0 429.40 168.18 224.94 NO 800. 10.86 1 3.0 3.4 960.0 429.40 188.30 293.55 NO**  **900. 15.06 1 2.0 2.3 640.0 607.47 228.42 384.54 NO 1000. 17.92 1 2.0 2.3 640.0 607.47 248.95 473.71 NO**  **1100. 18.39 1 2.0 2.3 640.0 607.47 269.15 573.82 NO 1200. 17.68 1 2.0 2.3 640.0 607.47 288.71 684.81 NO**  **1300. 16.89 1 2.0 2.3 640.0 607.47 304.03 805.43 NO 1400. 16.09 1 2.0 2.3 640.0 607.47 319.45 937.65 NO**  **1500. 15.45 1 1.5 1.7 786.5 785.55 360.99 1089.77 NO 1600. 14.85 1 1.5 1.7 786.5 785.55 375.46 1244.06 NO**  **1700. 14.30 1 1.5 1.7 786.5 785.55 390.04 1410.10 NO 1800. 13.78 1 1.5 1.7 786.5 785.55 404.72 1587.88 NO**  **1900. 13.30 1 1.5 1.7 786.5 785.55 419.46 1777.41 NO 2000. 12.84 1 1.5 1.7 786.5 785.55 434.26 1978.71 NO**  **2100. 12.42 1 1.5 1.7 786.5 785.55 449.09 2191.81 NO 2200. 12.02 1 1.5 1.7 786.5 785.55 463.96 2416.74 NO** **2300. 11.65 1 1.5 1.7 786.5 785.55 478.84 2653.55 NO 2400. 11.30 1 1.5 1.7 786.5 785.55 493.74 2902.27 NO**  **2500. 10.96 1 1.5 1.7 786.5 785.55 508.64 3162.96 NO 2600. 10.65 1 1.5 1.7 786.5 785.55 523.54 3435.64 NO**  **2700. 10.36 1 1.5 1.7 786.5 785.55 538.43 3720.38 NO 2800. 10.08 1 1.5 1.7 786.5 785.55 553.32 4017.22 NO**  **2900. 9.815 1 1.5 1.7 786.5 785.55 568.18 4326.19 NO 3000. 9.565 1 1.5 1.7 786.5 785.55 583.04 4647.34 NO**  **3500. 8.786 2 2.0 2.3 640.0 607.47 493.05 458.20 NO 4000. 8.679 2 2.0 2.3 640.0 607.47 548.96 522.97 NO**  **4500. 8.249 2 2.0 2.3 640.0 607.47 604.41 589.30 NO 5000. 7.828 2 1.5 1.7 786.5 785.55 672.98 670.57 NO** 

**MAXIMUM 1-HR CONCENTRATION AT OR BEYOND 200. M: 1075. 18.43 1 2.0 2.3 640.0 607.47 263.93 546.73 NO** 

**DWASH= MEANS NO CALC MADE (CONC = 0.0) DWASH=NO MEANS NO BUILDING DOWNWASH USED**  **DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED**  **DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB**

************************************************ *** SUMMARY OF TERRAIN HEIGHTS ENTERED FOR *** *** SIMPLE ELEVATED TERRAIN PROCEDURE *** ************************************************

**TERRAIN DISTANCE RANGE (M) HT (M) MINIMUM MAXIMUM** 

**------- -------- -------- 0. 200. 5000.** 

******************************************* ***** SUMMARY OF SCREEN MODEL RESULTS ***** *******************************************

**CALCULATION MAX CONC DIST TO TERRAIN PROCEDURE (UG/M** 3) MAX (M) HT (M)**

**-------------- ----------- ------- ------- SIMPLE TERRAIN 18.43 1075. 0.** 

*******************************************************   REMEMBER TO INCLUDE BACKGROUND CONCENTRATIONS ** ** *********************************************************1 03/10/08**  **12:28:12** ***** SCREEN3 MODEL RUN ***** ***** VERSION DATED 96043 *****

**CO - McELMO CREEK MAIN FLARE - 618104 SCF/HR; 538.8 BTU**

**SIMPLE TERRAIN INPUTS: SOURCE TYPE = FLARE**  **EMISSION RATE (G/S) = 23.0600 FLARE STACK HEIGHT (M) = 59.4500**  **TOT HEAT RLS (CAL/S) = .233276E+08**

**RECEPTOR HEIGHT (M) = .0000 URBAN/RURAL OPTION = RURAL**  **EFF RELEASE HEIGHT (M) = 74.6137 BUILDING HEIGHT (M) = .0000**  **MIN HORIZ BLDG DIM (M) = .0000 MAX HORIZ BLDG DIM (M) = .0000** 

**THE REGULATORY (DEFAULT) MIXING HEIGHT OPTION WAS SELECTED. THE REGULATORY (DEFAULT) ANEMOMETER HEIGHT OF 10.0 METERS WAS ENTERED.** 

**BUOY. FLUX = 386.779 M**4/S**3; MOM. FLUX = 235.850 M**4/S**2.**

***** FULL METEOROLOGY *****

************************************** ***** SCREEN AUTOMATED DISTANCES ***** **************************************

***** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES *****

**DIST CONC U10M USTK MIX HT PLUME SIGMA SIGMA (M) (UG/M** 3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DWASH**

**------- ---------- ---- ----- ----- ------ ------ ------ ------ ----- 200. .5902E-02 5 1.0 2.0 10000.0 245.91 50.30 49.34 NO**  **300. .6845E-02 5 1.0 2.0 10000.0 245.91 51.78 49.71 NO 400. .8008E-02 5 1.0 2.0 10000.0 245.91 53.66 50.12 NO**  **500. .6249E-01 1 3.0 3.5 960.0 474.63 128.33 121.01 NO 600. 1.599 1 3.0 3.5 960.0 474.63 149.55 168.54 NO**  **700. 6.133 1 3.0 3.5 960.0 474.63 170.23 226.48 NO 800. 10.37 1 3.0 3.5 960.0 474.63 190.49 294.96 NO**  **900. 15.43 1 2.0 2.3 675.6 674.64 233.15 387.37 NO 1000. 19.29 1 2.0 2.3 675.6 674.64 253.95 476.35 NO**  **1100. 20.37 1 2.0 2.3 675.6 674.64 274.40 576.30 NO 1200. 19.84 1 2.0 2.3 675.6 674.64 294.53 687.29 NO**  **1300. 18.81 1 2.0 2.3 675.6 674.64 313.89 809.20 NO 1400. 17.98 1 2.0 2.3 675.6 674.64 328.85 940.89 NO**  **1500. 17.20 1 2.0 2.3 675.6 674.64 343.93 1084.24 NO 1600. 16.47 1 2.0 2.3 675.6 674.64 359.09 1239.22 NO**  **1700. 15.80 1 2.0 2.3 675.6 674.64 374.31 1405.83 NO 1800. 15.18 1 2.0 2.3 675.6 674.64 389.58 1584.09 NO**  **1900. 14.61 1 2.0 2.3 675.6 674.64 404.87 1774.02 NO 2000. 14.08 1 2.0 2.3 675.6 674.64 420.18 1975.67 NO**  **2100. 13.58 1 2.0 2.3 675.6 674.64 435.50 2189.06 NO 2200. 13.12 1 2.0 2.3 675.6 674.64 450.81 2414.25 NO**  **2300. 12.69 1 2.0 2.3 675.6 674.64 466.12 2651.28 NO 2400. 12.29 1 2.0 2.3 675.6 674.64 481.41 2900.20 NO**  **2500. 11.91 1 2.0 2.3 675.6 674.64 496.68 3161.05 NO 2600. 11.55 1 2.0 2.3 675.6 674.64 511.92 3433.89 NO**  **2700. 11.22 1 2.0 2.3 675.6 674.64 527.15 3718.77 NO 2800. 10.91 1 2.0 2.3 675.6 674.64 542.34 4015.72 NO**  **2900. 10.61 1 2.0 2.3 675.6 674.64 557.50 4324.79 NO 3000. 10.33 1 2.0 2.3 675.6 674.64 572.63 4646.04 NO** **2 MAXIMUM 1-HR CONCENTRATION AT OR BEYOND 200. M:**  **1104. 20.37 1 2.0 2.3 675.6 674.64 275.01 579.47 NO**

**DWASH= MEANS NO CALC MADE (CONC = 0.0) DWASH=NO MEANS NO BUILDING DOWNWASH USED**  **DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED**  **DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB**

************************************* ***** SCREEN DISCRETE DISTANCES ***** *************************************

***** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES *****

**DIST CONC U10M USTK MIX HT PLUME SIGMA SIGMA (M) (UG/M** 3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DWASH**

**------- ---------- ---- ----- ----- ------ ------ ------ ------ ----- 3100. 10.06 1 2.0 2.3 675.6 674.64 587.73 4979.50 NO**  **3200. 9.812 1 2.0 2.3 675.6 674.64 602.79 5000.00 NO 3300. 9.573 1 2.0 2.3 675.6 674.64 617.82 5000.00 NO**  **3400. 9.466 2 2.0 2.3 675.6 674.64 488.10 452.26 NO 3500. 9.557 2 2.0 2.3 675.6 674.64 499.19 464.80 NO**  **3600. 9.620 2 2.0 2.3 675.6 674.64 510.27 477.44 NO 3700. 9.656 2 2.0 2.3 675.6 674.64 521.34 490.15 NO**  **3800. 9.667 2 2.0 2.3 675.6 674.64 532.40 502.95 NO 3900. 9.657 2 2.0 2.3 675.6 674.64 543.45 515.82 NO**  **4000. 9.628 2 2.0 2.3 675.6 674.64 554.48 528.76 NO 4100. 9.583 2 2.0 2.3 675.6 674.64 565.50 541.77 NO**  **4200. 9.523 2 2.0 2.3 675.6 674.64 576.51 554.85 NO 4300. 9.452 2 2.0 2.3 675.6 674.64 587.50 567.99 NO**  **4400. 9.370 2 2.0 2.3 675.6 674.64 598.47 581.19 NO 4500. 9.279 2 2.0 2.3 675.6 674.64 609.43 594.45 NO**  **4600. 9.182 2 2.0 2.3 675.6 674.64 620.38 607.77 NO 4700. 9.079 2 2.0 2.3 675.6 674.64 631.30 621.13 NO**  **4800. 8.973 2 2.0 2.3 675.6 674.64 642.21 634.55 NO 4900. 8.863 2 2.0 2.3 675.6 674.64 653.11 648.02 NO**  **5000. 8.751 2 2.0 2.3 675.6 674.64 663.98 661.54 NO**

**DWASH= MEANS NO CALC MADE (CONC = 0.0) DWASH=NO MEANS NO BUILDING DOWNWASH USED**  **DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED**  **DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB**

************************************************ *** SUMMARY OF TERRAIN HEIGHTS ENTERED FOR *** *** SIMPLE ELEVATED TERRAIN PROCEDURE *** ************************************************

**TERRAIN DISTANCE RANGE (M) HT (M) MINIMUM MAXIMUM** 

**------- -------- -------- 0. 200. 3000.**  **0. 3100. -- 0. 3200. --**  **0. 3300. -- 0. 3400. --**  **0. 3500. -- 0. 3600. --**  **0. 3700. -- 0. 3800. --**  **0. 3900. -- 0. 4000. --**  **0. 4100. -- 0. 4200. --** **3 0. 4300. --**  **0. 4400. -- 0. 4500. --**  **0. 4600. -- 0. 4700. --**  **0. 4800. -- 0. 4900. --**  **0. 5000. --**

******************************************* ***** SUMMARY OF SCREEN MODEL RESULTS ***** *******************************************

**CALCULATION MAX CONC DIST TO TERRAIN PROCEDURE (UG/M** 3) MAX (M) HT (M)**

**-------------- ----------- ------- ------- SIMPLE TERRAIN 20.37 1104. 0.** 

*******************************************************   REMEMBER TO INCLUDE BACKGROUND CONCENTRATIONS ** ** *********************************************************03/13/08 10:58:20**  ***** SCREEN3 MODEL RUN ***** ***** VERSION DATED 96043 *****

**CO - McELMO CREEK MAIN FLARE - 618,104 SCF/HR; 682.4 BTU/SCF**

**SIMPLE TERRAIN INPUTS: SOURCE TYPE = FLARE**  **EMISSION RATE (G/S) = 29.2100 FLARE STACK HEIGHT (M) = 59.4500**  **TOT HEAT RLS (CAL/S) = .295449E+08**

**RECEPTOR HEIGHT (M) = .0000 URBAN/RURAL OPTION = RURAL**  **EFF RELEASE HEIGHT (M) = 76.4268 BUILDING HEIGHT (M) = .0000**  **MIN HORIZ BLDG DIM (M) = .0000 MAX HORIZ BLDG DIM (M) = .0000** 

**THE REGULATORY (DEFAULT) MIXING HEIGHT OPTION WAS SELECTED. THE REGULATORY (DEFAULT) ANEMOMETER HEIGHT OF 10.0 METERS WAS ENTERED.** 

**BUOY. FLUX = 489.864 M**4/S**3; MOM. FLUX = 298.709 M**4/S**2.**

***** FULL METEOROLOGY *****

************************************** ***** SCREEN AUTOMATED DISTANCES ***** **************************************

***** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES *****

**DIST CONC U10M USTK MIX HT PLUME SIGMA SIGMA (M) (UG/M** 3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DWASH**

**------- ---------- ---- ----- ----- ------ ------ ------ ------ ----- 200. .9095E-02 5 1.0 2.0 10000.0 261.24 54.07 53.17 NO**  **300. .1029E-01 5 1.0 2.0 10000.0 261.24 55.44 53.52 NO 400. .1172E-01 5 1.0 2.0 10000.0 261.24 57.21 53.90 NO**  **500. .1352E-01 5 1.0 2.0 10000.0 261.24 59.31 54.33 NO 600. .7457 1 3.0 3.5 960.0 536.60 152.15 170.85 NO**  **700. 4.322 1 3.0 3.5 960.0 536.60 173.04 228.59 NO 800. 9.140 1 3.0 3.5 960.0 536.60 193.49 296.90 NO**  **900. 12.55 1 2.0 2.3 767.7 766.68 239.56 391.26 NO 1000. 17.94 1 2.0 2.3 767.7 766.68 260.73 480.00 NO**  **1100. 20.58 1 2.0 2.3 767.7 766.68 281.52 579.73 NO 1200. 20.99 1 2.0 2.3 767.7 766.68 301.99 690.52 NO**  **1300. 20.27 1 2.0 2.3 767.7 766.68 322.16 812.44 NO 1400. 19.22 1 2.0 2.3 767.7 766.68 342.05 945.58 NO**  **1500. 18.41 1 2.0 2.3 767.7 766.68 357.48 1088.61 NO 1600. 17.69 1 2.0 2.3 767.7 766.68 372.09 1243.05 NO**  **1700. 17.02 1 2.0 2.3 767.7 766.68 386.80 1409.21 NO 1800. 16.39 1 2.0 2.3 767.7 766.68 401.59 1587.09 NO**  **1900. 15.81 1 2.0 2.3 767.7 766.68 416.44 1776.70 NO 2000. 15.26 1 2.0 2.3 767.7 766.68 431.34 1978.07 NO**  **2100. 14.75 1 2.0 2.3 767.7 766.68 446.28 2191.23 NO 2200. 14.27 1 2.0 2.3 767.7 766.68 461.23 2416.22 NO**  **2300. 13.82 1 2.0 2.3 767.7 766.68 476.20 2653.07 NO 2400. 13.40 1 2.0 2.3 767.7 766.68 491.18 2901.84 NO**  **2500. 13.01 1 2.0 2.3 767.7 766.68 506.15 3162.56 NO 2600. 12.63 1 2.0 2.3 767.7 766.68 521.12 3435.28 NO**  **2700. 12.28 1 2.0 2.3 767.7 766.68 536.08 3720.04 NO 2800. 11.95 1 2.0 2.3 767.7 766.68 551.03 4016.90 NO**  **2900. 11.63 1 2.0 2.3 767.7 766.68 565.96 4325.89 NO 3000. 11.33 1 2.0 2.3 767.7 766.68 580.87 4647.06 NO** 

**MAXIMUM 1-HR CONCENTRATION AT OR BEYOND 200. M: 1174. 21.04 1 2.0 2.3 767.7 766.68 296.49 659.51 NO** 

**DWASH= MEANS NO CALC MADE (CONC = 0.0) DWASH=NO MEANS NO BUILDING DOWNWASH USED**  **DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED**  **DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB**

************************************* ***** SCREEN DISCRETE DISTANCES ***** *************************************

***** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES *****

**DIST CONC U10M USTK MIX HT PLUME SIGMA SIGMA (M) (UG/M** 3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DWASH**

**------- ---------- ---- ----- ----- ------ ------ ------ ------ ----- 3100. 11.05 1 2.0 2.3 767.7 766.68 595.76 4980.46 NO**  **3200. 10.78 1 2.0 2.3 767.7 766.68 610.62 5000.00 NO 3300. 10.52 1 2.0 2.3 767.7 766.68 625.46 5000.00 NO**  **3400. 10.28 1 2.0 2.3 767.7 766.68 640.27 5000.00 NO 3500. 10.05 1 2.0 2.3 767.7 766.68 655.06 5000.00 NO**  **3600. 9.828 1 2.0 2.3 767.7 766.68 669.81 5000.00 NO 3700. 9.616 1 2.0 2.3 767.7 766.68 684.54 5000.00 NO**  **3800. 9.464 2 2.0 2.3 767.7 766.68 541.25 512.31 NO 3900. 9.552 2 2.0 2.3 767.7 766.68 552.12 524.95 NO**  **4000. 9.616 2 2.0 2.3 767.7 766.68 562.99 537.67 NO 4100. 9.658 2 2.0 2.3 767.7 766.68 573.84 550.47 NO**  **4200. 9.680 2 2.0 2.3 767.7 766.68 584.69 563.35 NO 4300. 9.684 2 2.0 2.3 767.7 766.68 595.53 576.30 NO**  **4400. 9.671 2 2.0 2.3 767.7 766.68 606.36 589.31 NO 4500. 9.644 2 2.0 2.3 767.7 766.68 617.18 602.39 NO**  **4600. 9.604 2 2.0 2.3 767.7 766.68 627.99 615.53 NO 4700. 9.552 2 2.0 2.3 767.7 766.68 638.79 628.74 NO**  **4800. 9.491 2 2.0 2.3 767.7 766.68 649.57 642.00 NO 4900. 9.422 2 2.0 2.3 767.7 766.68 660.34 655.31 NO**  **5000. 9.345 2 2.0 2.3 767.7 766.68 671.10 668.68 NO**

**DWASH= MEANS NO CALC MADE (CONC = 0.0) DWASH=NO MEANS NO BUILDING DOWNWASH USED**  **DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED**  **DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB**

************************************************ *** SUMMARY OF TERRAIN HEIGHTS ENTERED FOR ****** SIMPLE ELEVATED TERRAIN PROCEDURE *** ************************************************

**TERRAIN DISTANCE RANGE (M) HT (M) MINIMUM MAXIMUM** 

**------- -------- -------- 0. 200. 3000.**  **0. 3100. -- 0. 3200. --**  **0. 3300. -- 0. 3400. --**  **0. 3500. -- 0. 3600. --**  **0. 3700. -- 0. 3800. --**  **0. 3900. -- 0. 4000. --**  **0. 4100. -- 0. 4200. --**  **0. 4300. -- 0. 4400. --**  **0. 4500. -- 0. 4600. --**  **0. 4700. -- 0. 4800. --**  **0. 4900. -- 0. 5000. --** 

******************************************* ***** SUMMARY OF SCREEN MODEL RESULTS ***** *******************************************

**CALCULATION MAX CONC DIST TO TERRAIN PROCEDURE (UG/M** 3) MAX (M) HT (M)**

**-------------- ----------- ------- ------- SIMPLE TERRAIN 21.04 1174. 0.** 

*******************************************************   REMEMBER TO INCLUDE BACKGROUND CONCENTRATIONS ** ** *********************************************************10/07/05 18:43:30**  ***** SCREEN3 MODEL RUN ***** ***** VERSION DATED 96043 *****

**SO2 - McELMO CREEK MAIN FLARE - 618.104 SCF/HR; 300 BTU/SCF; 700 PPM H2S**

**SIMPLE TERRAIN INPUTS: SOURCE TYPE = FLARE**  **EMISSION RATE (G/S) = 9.21000 FLARE STACK HEIGHT (M) = 59.4500**  **TOT HEAT RLS (CAL/S) = .129887E+08 RECEPTOR HEIGHT (M) = .0000**  **URBAN/RURAL OPTION = RURAL EFF RELEASE HEIGHT (M) = 70.9117**  **BUILDING HEIGHT (M) = .0000 MIN HORIZ BLDG DIM (M) = .0000**  **MAX HORIZ BLDG DIM (M) = .0000**

**THE REGULATORY (DEFAULT) MIXING HEIGHT OPTION WAS SELECTED. THE REGULATORY (DEFAULT) ANEMOMETER HEIGHT OF 10.0 METERS WAS ENTERED.** 

**BUOY. FLUX = 215.357 M**4/S**3; MOM. FLUX = 131.320 M**4/S**2.**

***** FULL METEOROLOGY *****

************************************** ***** SCREEN AUTOMATED DISTANCES ***** **************************************

***** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES *****

**DIST CONC U10M USTK MIX HT PLUME SIGMA SIGMA (M) (UG/M** 3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DWASH**

**------- ---------- ---- ----- ----- ------ ------ ------ ------ ----- 200. .1213E-02 5 1.0 2.0 10000.0 212.67 42.14 40.98 NO**  **300. .1537E-02 5 1.0 2.0 10000.0 212.67 43.89 41.43 NO 400. .1224E-01 1 3.0 3.4 960.0 353.43 102.30 83.27 NO**  **500. .5749 1 3.0 3.4 960.0 353.43 123.67 116.05 NO 600. 3.529 1 3.0 3.4 960.0 353.43 144.45 164.03 NO**  **700. 6.577 1 3.0 3.4 960.0 353.43 164.74 222.37 NO 800. 7.587 1 3.0 3.4 960.0 353.43 184.62 291.21 NO**  **900. 9.638 1 1.5 1.7 636.9 635.95 241.27 392.31 NO 1000. 11.24 1 1.5 1.7 636.9 635.95 262.53 480.98 NO**  **1100. 11.63 1 1.5 1.7 636.9 635.95 278.55 578.29 NO 1200. 11.35 1 1.5 1.7 636.9 635.95 293.46 686.83 NO**  **1300. 10.86 1 1.5 1.7 636.9 635.95 308.54 807.14 NO 1400. 10.36 1 1.5 1.7 636.9 635.95 323.75 939.12 NO**  **1500. 9.889 1 1.5 1.7 636.9 635.95 339.05 1082.70 NO 1600. 9.460 1 1.5 1.7 636.9 635.95 354.42 1237.88 NO**  **1700. 9.066 1 1.5 1.7 636.9 635.95 369.84 1404.65 NO 1800. 8.703 1 1.5 1.7 636.9 635.95 385.28 1583.04 NO**  **1900. 8.367 1 1.5 1.7 636.9 635.95 400.74 1773.09 NO 2000. 8.056 1 1.5 1.7 636.9 635.95 416.20 1974.82 NO**  **2100. 7.768 1 1.5 1.7 636.9 635.95 431.66 2188.30 NO 2200. 7.499 1 1.5 1.7 636.9 635.95 447.11 2413.56 NO** **2300. 7.249 1 1.5 1.7 636.9 635.95 462.53 2650.65 NO 2400. 7.015 1 1.5 1.7 636.9 635.95 477.94 2899.62 NO**  **2500. 6.797 1 1.5 1.7 636.9 635.95 493.32 3160.53 NO 2600. 6.592 1 1.5 1.7 636.9 635.95 508.66 3433.41 NO**  **2700. 6.399 1 1.5 1.7 636.9 635.95 523.98 3718.32 NO 2800. 6.218 1 1.5 1.7 636.9 635.95 539.26 4015.30 NO**  **2900. 6.047 1 1.5 1.7 636.9 635.95 554.51 4324.41 NO 3000. 5.885 1 1.5 1.7 636.9 635.95 569.72 4645.68 NO**  **3500. 5.745 2 1.5 1.7 636.9 635.95 495.84 461.21 NO 4000. 5.658 2 1.5 1.7 636.9 635.95 551.47 525.60 NO**  **4500. 5.370 2 1.5 1.7 636.9 635.95 606.70 591.64 NO 5000. 5.017 2 1.5 1.7 636.9 635.95 661.47 659.02 NO** 

**MAXIMUM 1-HR CONCENTRATION AT OR BEYOND 200. M: 1097. 11.63 1 1.5 1.7 636.9 635.95 277.95 574.19 NO** 

**DWASH= MEANS NO CALC MADE (CONC = 0.0) DWASH=NO MEANS NO BUILDING DOWNWASH USED**  **DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED**  **DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB**

************************************************ *** SUMMARY OF TERRAIN HEIGHTS ENTERED FOR *** *** SIMPLE ELEVATED TERRAIN PROCEDURE *** ************************************************

**TERRAIN DISTANCE RANGE (M) HT (M) MINIMUM MAXIMUM** 

**------- -------- -------- 0. 200. 5000.** 

******************************************* ***** SUMMARY OF SCREEN MODEL RESULTS ***** *******************************************

**CALCULATION MAX CONC DIST TO TERRAIN PROCEDURE (UG/M** 3) MAX (M) HT (M)**

**-------------- ----------- ------- ------- SIMPLE TERRAIN 11.63 1097. 0.** 

*******************************************************   REMEMBER TO INCLUDE BACKGROUND CONCENTRATIONS ** ** *********************************************************10/07/05 18:34:49**  ***** SCREEN3 MODEL RUN ***** ***** VERSION DATED 96043 *****

**SO2 - McELMO CREEK MAIN FLARE - 618.104 SCF/HR; 443 BTU/SCF; 700 PPM H2S**

**SIMPLE TERRAIN INPUTS: SOURCE TYPE = FLARE**  **EMISSION RATE (G/S) = 9.21000 FLARE STACK HEIGHT (M) = 59.4500**  **TOT HEAT RLS (CAL/S) = .191799E+08 RECEPTOR HEIGHT (M) = .0000**  **URBAN/RURAL OPTION = RURAL EFF RELEASE HEIGHT (M) = 73.2591**  **BUILDING HEIGHT (M) = .0000 MIN HORIZ BLDG DIM (M) = .0000**  **MAX HORIZ BLDG DIM (M) = .0000**

**THE REGULATORY (DEFAULT) MIXING HEIGHT OPTION WAS SELECTED. THE REGULATORY (DEFAULT) ANEMOMETER HEIGHT OF 10.0 METERS WAS ENTERED.** 

**BUOY. FLUX = 318.009 M**4/S**3; MOM. FLUX = 193.915 M**4/S**2.**

***** FULL METEOROLOGY *****

************************************** ***** SCREEN AUTOMATED DISTANCES ***** **************************************

***** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES *****

**DIST CONC U10M USTK MIX HT PLUME SIGMA SIGMA (M) (UG/M** 3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DWASH**

**------- ---------- ---- ----- ----- ------ ------ ------ ------ ----- 200. .1945E-02 5 1.0 2.0 10000.0 234.08 47.40 46.37 NO**  **300. .2312E-02 5 1.0 2.0 10000.0 234.08 48.96 46.76 NO 400. .2776E-02 5 1.0 2.0 10000.0 234.08 50.95 47.20 NO**  **500. .8538E-01 1 3.0 3.4 960.0 429.40 126.59 119.17 NO 600. 1.258 1 3.0 3.4 960.0 429.40 147.64 166.85 NO**  **700. 3.633 1 3.0 3.4 960.0 429.40 168.18 224.94 NO 800. 5.276 1 3.0 3.4 960.0 429.40 188.30 293.55 NO**  **900. 7.314 1 2.0 2.3 640.0 607.47 228.42 384.54 NO 1000. 8.704 1 2.0 2.3 640.0 607.47 248.95 473.71 NO**  **1100. 8.931 1 2.0 2.3 640.0 607.47 269.15 573.82 NO 1200. 8.589 1 2.0 2.3 640.0 607.47 288.71 684.81 NO**  **1300. 8.207 1 2.0 2.3 640.0 607.47 304.03 805.43 NO 1400. 7.816 1 2.0 2.3 640.0 607.47 319.45 937.65 NO**  **1500. 7.503 1 1.5 1.7 786.5 785.55 360.99 1089.77 NO 1600. 7.215 1 1.5 1.7 786.5 785.55 375.46 1244.06 NO**  **1700. 6.945 1 1.5 1.7 786.5 785.55 390.04 1410.10 NO 1800. 6.694 1 1.5 1.7 786.5 785.55 404.72 1587.88 NO**  **1900. 6.458 1 1.5 1.7 786.5 785.55 419.46 1777.41 NO 2000. 6.238 1 1.5 1.7 786.5 785.55 434.26 1978.71 NO**  **2100. 6.032 1 1.5 1.7 786.5 785.55 449.09 2191.81 NO 2200. 5.839 1 1.5 1.7 786.5 785.55 463.96 2416.74 NO** **2300. 5.657 1 1.5 1.7 786.5 785.55 478.84 2653.55 NO 2400. 5.487 1 1.5 1.7 786.5 785.55 493.74 2902.27 NO**  **2500. 5.326 1 1.5 1.7 786.5 785.55 508.64 3162.96 NO 2600. 5.174 1 1.5 1.7 786.5 785.55 523.54 3435.64 NO**  **2700. 5.031 1 1.5 1.7 786.5 785.55 538.43 3720.38 NO 2800. 4.896 1 1.5 1.7 786.5 785.55 553.32 4017.22 NO**  **2900. 4.768 1 1.5 1.7 786.5 785.55 568.18 4326.19 NO 3000. 4.646 1 1.5 1.7 786.5 785.55 583.04 4647.34 NO**  **3500. 4.268 2 2.0 2.3 640.0 607.47 493.05 458.20 NO 4000. 4.216 2 2.0 2.3 640.0 607.47 548.96 522.97 NO**  **4500. 4.007 2 2.0 2.3 640.0 607.47 604.41 589.30 NO 5000. 3.803 2 1.5 1.7 786.5 785.55 672.98 670.57 NO** 

**MAXIMUM 1-HR CONCENTRATION AT OR BEYOND 200. M: 1075. 8.951 1 2.0 2.3 640.0 607.47 263.93 546.73 NO** 

**DWASH= MEANS NO CALC MADE (CONC = 0.0) DWASH=NO MEANS NO BUILDING DOWNWASH USED**  **DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED**  **DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB**

************************************************ *** SUMMARY OF TERRAIN HEIGHTS ENTERED FOR *** *** SIMPLE ELEVATED TERRAIN PROCEDURE *** ************************************************

**TERRAIN DISTANCE RANGE (M) HT (M) MINIMUM MAXIMUM** 

**------- -------- -------- 0. 200. 5000.** 

******************************************* ***** SUMMARY OF SCREEN MODEL RESULTS ***** *******************************************

**CALCULATION MAX CONC DIST TO TERRAIN PROCEDURE (UG/M** 3) MAX (M) HT (M)**

**-------------- ----------- ------- ------- SIMPLE TERRAIN 8.951 1075. 0.** 

*******************************************************   REMEMBER TO INCLUDE BACKGROUND CONCENTRATIONS ** ** *******************************************************1 **03/10/08 12:31:24**  ***** SCREEN3 MODEL RUN ***** ***** VERSION DATED 96043 *****

**SO2 - McELMO CREEK MAIN FLARE - 618104 SCF/HR; 538 BTU**

**SIMPLE TERRAIN INPUTS: SOURCE TYPE = FLARE**  **EMISSION RATE (G/S) = 9.18000 FLARE STACK HEIGHT (M) = 59.4500**  **TOT HEAT RLS (CAL/S) = .233276E+08**

**RECEPTOR HEIGHT (M) = .0000 URBAN/RURAL OPTION = RURAL**  **EFF RELEASE HEIGHT (M) = 74.6137 BUILDING HEIGHT (M) = .0000**  **MIN HORIZ BLDG DIM (M) = .0000 MAX HORIZ BLDG DIM (M) = .0000** 

**THE REGULATORY (DEFAULT) MIXING HEIGHT OPTION WAS SELECTED. THE REGULATORY (DEFAULT) ANEMOMETER HEIGHT OF 10.0 METERS WAS ENTERED.** 

**BUOY. FLUX = 386.779 M**4/S**3; MOM. FLUX = 235.850 M**4/S**2.**

***** FULL METEOROLOGY *****

************************************** ***** SCREEN AUTOMATED DISTANCES ***** **************************************

***** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES *****

**DIST CONC U10M USTK MIX HT PLUME SIGMA SIGMA (M) (UG/M** 3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DWASH**

**------- ---------- ---- ----- ----- ------ ------ ------ ------ ----- 200. .2349E-02 5 1.0 2.0 10000.0 245.91 50.30 49.34 NO**  **300. .2725E-02 5 1.0 2.0 10000.0 245.91 51.78 49.71 NO 400. .3188E-02 5 1.0 2.0 10000.0 245.91 53.66 50.12 NO**  **500. .2488E-01 1 3.0 3.5 960.0 474.63 128.33 121.01 NO 600. .6365 1 3.0 3.5 960.0 474.63 149.55 168.54 NO**  **700. 2.442 1 3.0 3.5 960.0 474.63 170.23 226.48 NO 800. 4.126 1 3.0 3.5 960.0 474.63 190.49 294.96 NO**  **900. 6.141 1 2.0 2.3 675.6 674.64 233.15 387.37 NO 1000. 7.677 1 2.0 2.3 675.6 674.64 253.95 476.35 NO**  **1100. 8.107 1 2.0 2.3 675.6 674.64 274.40 576.30 NO 1200. 7.897 1 2.0 2.3 675.6 674.64 294.53 687.29 NO**  **1300. 7.489 1 2.0 2.3 675.6 674.64 313.89 809.20 NO 1400. 7.159 1 2.0 2.3 675.6 674.64 328.85 940.89 NO**  **1500. 6.846 1 2.0 2.3 675.6 674.64 343.93 1084.24 NO 1600. 6.557 1 2.0 2.3 675.6 674.64 359.09 1239.22 NO**  **1700. 6.290 1 2.0 2.3 675.6 674.64 374.31 1405.83 NO 1800. 6.044 1 2.0 2.3 675.6 674.64 389.58 1584.09 NO**  **1900. 5.816 1 2.0 2.3 675.6 674.64 404.87 1774.02 NO 2000. 5.604 1 2.0 2.3 675.6 674.64 420.18 1975.67 NO**  **2100. 5.407 1 2.0 2.3 675.6 674.64 435.50 2189.06 NO 2200. 5.223 1 2.0 2.3 675.6 674.64 450.81 2414.25 NO**  **2300. 5.051 1 2.0 2.3 675.6 674.64 466.12 2651.28 NO 2400. 4.891 1 2.0 2.3 675.6 674.64 481.41 2900.20 NO**  **2500. 4.741 1 2.0 2.3 675.6 674.64 496.68 3161.05 NO 2600. 4.599 1 2.0 2.3 675.6 674.64 511.92 3433.89 NO**  **2700. 4.467 1 2.0 2.3 675.6 674.64 527.15 3718.77 NO 2800. 4.341 1 2.0 2.3 675.6 674.64 542.34 4015.72 NO**  **2900. 4.223 1 2.0 2.3 675.6 674.64 557.50 4324.79 NO 3000. 4.112 1 2.0 2.3 675.6 674.64 572.63 4646.04 NO** 2 **MAXIMUM 1-HR CONCENTRATION AT OR BEYOND 200. M: 1104. 8.108 1 2.0 2.3 675.6 674.64 275.01 579.47 NO** 

**DWASH= MEANS NO CALC MADE (CONC = 0.0) DWASH=NO MEANS NO BUILDING DOWNWASH USED**  **DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED**  **DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB**

************************************* ***** SCREEN DISCRETE DISTANCES ***** *************************************

***** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES *****

**DIST CONC U10M USTK MIX HT PLUME SIGMA SIGMA (M) (UG/M** 3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DWASH**

**------- ---------- ---- ----- ----- ------ ------ ------ ------ ----- 3100. 4.006 1 2.0 2.3 675.6 674.64 587.73 4979.50 NO**  **3200. 3.906 1 2.0 2.3 675.6 674.64 602.79 5000.00 NO 3300. 3.811 1 2.0 2.3 675.6 674.64 617.82 5000.00 NO**  **3400. 3.768 2 2.0 2.3 675.6 674.64 488.10 452.26 NO 3500. 3.805 2 2.0 2.3 675.6 674.64 499.19 464.80 NO**  **3600. 3.830 2 2.0 2.3 675.6 674.64 510.27 477.44 NO 3700. 3.844 2 2.0 2.3 675.6 674.64 521.34 490.15 NO**  **3800. 3.848 2 2.0 2.3 675.6 674.64 532.40 502.95 NO 3900. 3.844 2 2.0 2.3 675.6 674.64 543.45 515.82 NO**  **4000. 3.833 2 2.0 2.3 675.6 674.64 554.48 528.76 NO 4100. 3.815 2 2.0 2.3 675.6 674.64 565.50 541.77 NO**  **4200. 3.791 2 2.0 2.3 675.6 674.64 576.51 554.85 NO 4300. 3.763 2 2.0 2.3 675.6 674.64 587.50 567.99 NO**  **4400. 3.730 2 2.0 2.3 675.6 674.64 598.47 581.19 NO 4500. 3.694 2 2.0 2.3 675.6 674.64 609.43 594.45 NO**  **4600. 3.655 2 2.0 2.3 675.6 674.64 620.38 607.77 NO 4700. 3.614 2 2.0 2.3 675.6 674.64 631.30 621.13 NO**  **4800. 3.572 2 2.0 2.3 675.6 674.64 642.21 634.55 NO 4900. 3.528 2 2.0 2.3 675.6 674.64 653.11 648.02 NO**  **5000. 3.484 2 2.0 2.3 675.6 674.64 663.98 661.54 NO**

**DWASH= MEANS NO CALC MADE (CONC = 0.0) DWASH=NO MEANS NO BUILDING DOWNWASH USED**  **DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED**  **DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB**

************************************************ *** SUMMARY OF TERRAIN HEIGHTS ENTERED FOR *** *** SIMPLE ELEVATED TERRAIN PROCEDURE *** ************************************************

**TERRAIN DISTANCE RANGE (M) HT (M) MINIMUM MAXIMUM** 

**------- -------- -------- 0. 200. 3000.**  **0. 3100. -- 0. 3200. --**  **0. 3300. -- 0. 3400. --**  **0. 3500. -- 0. 3600. --**  **0. 3700. -- 0. 3800. --**  **0. 3900. -- 0. 4000. --**  **0. 4100. -- 0. 4200. --** 3 **0. 4300. -- 0. 4400. --**  **0. 4500. -- 0. 4600. --**  **0. 4700. -- 0. 4800. --**  **0. 4900. -- 0. 5000. --** 

******************************************* ***** SUMMARY OF SCREEN MODEL RESULTS ***** *******************************************

**CALCULATION MAX CONC DIST TO TERRAIN PROCEDURE (UG/M** 3) MAX (M) HT (M)**

**-------------- ----------- ------- ------- SIMPLE TERRAIN 8.108 1104. 0.** 

*******************************************************   REMEMBER TO INCLUDE BACKGROUND CONCENTRATIONS ** ** *********************************************************1 03/10/08**  **12:41:18** ***** SCREEN3 MODEL RUN ***** ***** VERSION DATED 96043 *****

**SO2 - McELMO CREEK MAIN FLARE - 618104 SCF/HR; 682.4 BTU/SCF**

**SIMPLE TERRAIN INPUTS: SOURCE TYPE = FLARE**  **EMISSION RATE (G/S) = 9.18000 FLARE STACK HEIGHT (M) = 59.4500**  **TOT HEAT RLS (CAL/S) = .295449E+08**

**RECEPTOR HEIGHT (M) = .0000 URBAN/RURAL OPTION = RURAL**  **EFF RELEASE HEIGHT (M) = 76.4268 BUILDING HEIGHT (M) = .0000**  **MIN HORIZ BLDG DIM (M) = .0000 MAX HORIZ BLDG DIM (M) = .0000** 

**THE REGULATORY (DEFAULT) MIXING HEIGHT OPTION WAS SELECTED. THE REGULATORY (DEFAULT) ANEMOMETER HEIGHT OF 10.0 METERS WAS ENTERED.** 

**BUOY. FLUX = 489.864 M**4/S**3; MOM. FLUX = 298.709 M**4/S**2.**

***** FULL METEOROLOGY *****

************************************** ***** SCREEN AUTOMATED DISTANCES ***** **************************************

***** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES *****

**DIST CONC U10M USTK MIX HT PLUME SIGMA SIGMA (M) (UG/M** 3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DWASH**

**------- ---------- ---- ----- ----- ------ ------ ------ ------ ----- 200. .2858E-02 5 1.0 2.0 10000.0 261.24 54.07 53.17 NO**  **300. .3233E-02 5 1.0 2.0 10000.0 261.24 55.44 53.52 NO 400. .3685E-02 5 1.0 2.0 10000.0 261.24 57.21 53.90 NO**  **500. .4250E-02 5 1.0 2.0 10000.0 261.24 59.31 54.33 NO 600. .2343 1 3.0 3.5 960.0 536.60 152.15 170.85 NO**  **700. 1.358 1 3.0 3.5 960.0 536.60 173.04 228.59 NO 800. 2.872 1 3.0 3.5 960.0 536.60 193.49 296.90 NO**  **900. 3.945 1 2.0 2.3 767.7 766.68 239.56 391.26 NO 1000. 5.637 1 2.0 2.3 767.7 766.68 260.73 480.00 NO**  **1100. 6.468 1 2.0 2.3 767.7 766.68 281.52 579.73 NO 1200. 6.598 1 2.0 2.3 767.7 766.68 301.99 690.52 NO**  **1300. 6.371 1 2.0 2.3 767.7 766.68 322.16 812.44 NO 1400. 6.041 1 2.0 2.3 767.7 766.68 342.05 945.58 NO**  **1500. 5.787 1 2.0 2.3 767.7 766.68 357.48 1088.61 NO 1600. 5.560 1 2.0 2.3 767.7 766.68 372.09 1243.05 NO**  **1700. 5.348 1 2.0 2.3 767.7 766.68 386.80 1409.21 NO 1800. 5.151 1 2.0 2.3 767.7 766.68 401.59 1587.09 NO**  **1900. 4.968 1 2.0 2.3 767.7 766.68 416.44 1776.70 NO 2000. 4.796 1 2.0 2.3 767.7 766.68 431.34 1978.07 NO**  **2100. 4.636 1 2.0 2.3 767.7 766.68 446.28 2191.23 NO 2200. 4.485 1 2.0 2.3 767.7 766.68 461.23 2416.22 NO**  **2300. 4.344 1 2.0 2.3 767.7 766.68 476.20 2653.07 NO 2400. 4.212 1 2.0 2.3 767.7 766.68 491.18 2901.84 NO**  **2500. 4.087 1 2.0 2.3 767.7 766.68 506.15 3162.56 NO 2600. 3.970 1 2.0 2.3 767.7 766.68 521.12 3435.28 NO**  **2700. 3.859 1 2.0 2.3 767.7 766.68 536.08 3720.04 NO 2800. 3.754 1 2.0 2.3 767.7 766.68 551.03 4016.90 NO**  **2900. 3.655 1 2.0 2.3 767.7 766.68 565.96 4325.89 NO 3000. 3.561 1 2.0 2.3 767.7 766.68 580.87 4647.06 NO** **2 MAXIMUM 1-HR CONCENTRATION AT OR BEYOND 200. M:**  **1174. 6.612 1 2.0 2.3 767.7 766.68 296.49 659.51 NO**

**DWASH= MEANS NO CALC MADE (CONC = 0.0) DWASH=NO MEANS NO BUILDING DOWNWASH USED**  **DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED**  **DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB**

************************************* ***** SCREEN DISCRETE DISTANCES ***** *************************************

***** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES *****

**DIST CONC U10M USTK MIX HT PLUME SIGMA SIGMA (M) (UG/M** 3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DWASH**

**------- ---------- ---- ----- ----- ------ ------ ------ ------ ----- 3100. 3.472 1 2.0 2.3 767.7 766.68 595.76 4980.46 NO**  **3200. 3.388 1 2.0 2.3 767.7 766.68 610.62 5000.00 NO 3300. 3.308 1 2.0 2.3 767.7 766.68 625.46 5000.00 NO**  **3400. 3.231 1 2.0 2.3 767.7 766.68 640.27 5000.00 NO 3500. 3.158 1 2.0 2.3 767.7 766.68 655.06 5000.00 NO**  **3600. 3.089 1 2.0 2.3 767.7 766.68 669.81 5000.00 NO 3700. 3.022 1 2.0 2.3 767.7 766.68 684.54 5000.00 NO**  **3800. 2.974 2 2.0 2.3 767.7 766.68 541.25 512.31 NO 3900. 3.002 2 2.0 2.3 767.7 766.68 552.12 524.95 NO**  **4000. 3.022 2 2.0 2.3 767.7 766.68 562.99 537.67 NO 4100. 3.035 2 2.0 2.3 767.7 766.68 573.84 550.47 NO**  **4200. 3.042 2 2.0 2.3 767.7 766.68 584.69 563.35 NO 4300. 3.043 2 2.0 2.3 767.7 766.68 595.53 576.30 NO**  **4400. 3.039 2 2.0 2.3 767.7 766.68 606.36 589.31 NO 4500. 3.031 2 2.0 2.3 767.7 766.68 617.18 602.39 NO**  **4600. 3.018 2 2.0 2.3 767.7 766.68 627.99 615.53 NO 4700. 3.002 2 2.0 2.3 767.7 766.68 638.79 628.74 NO**  **4800. 2.983 2 2.0 2.3 767.7 766.68 649.57 642.00 NO 4900. 2.961 2 2.0 2.3 767.7 766.68 660.34 655.31 NO**  **5000. 2.937 2 2.0 2.3 767.7 766.68 671.10 668.68 NO**

**DWASH= MEANS NO CALC MADE (CONC = 0.0) DWASH=NO MEANS NO BUILDING DOWNWASH USED**  **DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED**  **DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB**

************************************************ *** SUMMARY OF TERRAIN HEIGHTS ENTERED FOR *** *** SIMPLE ELEVATED TERRAIN PROCEDURE *** ************************************************

**TERRAIN DISTANCE RANGE (M) HT (M) MINIMUM MAXIMUM** 

**------- -------- -------- 0. 200. 3000.**  **0. 3100. -- 0. 3200. --**  **0. 3300. -- 0. 3400. --**  **0. 3500. -- 0. 3600. --**  **0. 3700. -- 0. 3800. --**  **0. 3900. -- 0. 4000. --**  **0. 4100. -- 0. 4200. --** **3 0. 4300. --**  **0. 4400. -- 0. 4500. --**  **0. 4600. -- 0. 4700. --**  **0. 4800. -- 0. 4900. --**  **0. 5000. --**

******************************************* ***** SUMMARY OF SCREEN MODEL RESULTS ***** *******************************************

**CALCULATION MAX CONC DIST TO TERRAIN PROCEDURE (UG/M** 3) MAX (M) HT (M)**

**-------------- ----------- ------- ------- SIMPLE TERRAIN 6.612 1174. 0.** 

*******************************************************   REMEMBER TO INCLUDE BACKGROUND CONCENTRATIONS ** ** *******************************************************

### APPENDIX D

E-MAILS FROM MR. JOHN NOTAR of the NATIONAL PARK SERVICE and MR. HENRY MADDUX, UTAH ENDANGERED SPECIES SUPERVISOR

### E-MAIL FROM MR. JOHN NOTAR CO NCERNING CLASS I AREA IMPACTS

----- Forwarded by Justin J Harrison/U-Houston/ExxonMobil on 06/22/06 10:24 AM -----

John_Notar@nps .gov To justin.j.harrison@exxonmobil.com 06/21/06 04:59 cc PM Liana_Reilly@nps.gov, John_Bunyak@nps.gov, John_Vimont@nps.gov Subject Re: Class I Analysis for McElmo Creek PSD Permit Application

Justin: Thank you for the information on the McElmo Creek upset flare project at the Mc Elmo Creek compresso r station. Based on the information provided below and on the call; giv en the distance to the nearest National Park Service Class I area of 61 kilome ters to Mesa Verde National Park, and the total emissions of 60 TPY of SO2, 13 TPY of NOx from the project, the National Park Service does not request that a Class I air quality analysis be performed due to the small amount of emissions and the distance to the nearest NPS Class I area. Please share this information with EPA Region 9, the permitting authority for this project in Utah. If you have further questions on this issue please cont act Liana Reilly of the NPS Air Resources Division at (303)-987-6895. thanks you John Notar

John Notar National Park Service Air Resources Division 12795 W. Alameda Pkwy. Lakewood, CO 80228 Phone: 303-969-2079 Fax: 303-969-2822 E-Mail: john_notar@nps.gov

justin.j.harrison@exx

onmobil.com To: John_Notar@nps.gov

cc:

06/15/2006 04:55 PM Subject: Class I Analysis for McElmo Creek PSD Permit Application EST

John,

As we discussed today, ExxonMobil submitted a PSD permit application to EPA Region IX on December 5, 2005 for the Emergency Flare located at McElmo Creek Gas Compression Facility. In their response letter dated May 22, 2006, EPA asked us to contact you to determine if additional Class I screening is necessary.

The facility is located on the Navajo Nation approximately 4-5 miles northwest of Aneth, Utah, 3 miles from Utah State Road 262. It is comprised of four compressors, a dehydration unit, and an emergency flare, which is used during compressor downtime and to control dehydration still vent emissions. The current emission limits for the flare are as follows: 60 TPY SO2, 73 TPY CO, 13.4 TPY NOx, and 95.4 TPY VOCs. We do notanticipate any changes to these limits.

Total emissions for 2005 were: 29.2 tons SO2, 66 tons CO, 12.1 tons NOx, and 90.6 tons VOCs. During normal operations when all compressors are running, daily flare volumes are typically less than 500 kcf. Average daily flare volumes for 2005 were 2 MMCF.

Arches National Park and Canyonlands National Park are located to the northwest, approximately 160 km (100 miles) and 96 km (60 miles), respectively. Mesa Verde National Park is located approximately 60 km (38 miles) east of the gas plant site. The western boundary of the Canyon of the Ancients National Monument is approximately 16 km (10 miles) northwest of the plant site.

A conservative SCREEN 3 model was submitted in the PSD application to estimate near-field impacts from the flare operating at 14.83 MMCFD for the entire year, which is 7 times greater than the average emissions in 2005. With respect to NOx and SO2, th is model estimated the following concentrations:

The predicted maximum annual aver aged NO2 concentration from the flare is 0.13 micrograms/cubic meter located 1,075 meters from the stack. The predicted maximum 3-hour, 24-hour, and annual averaged SO2 concentrations from the flare ar e 10.47, 4.65, and 0.93 micrograms/cubic meter, respectively, located 1,097 meters from the stack.

As you indicated today, you did not feel that any additional Class I screening would be necessary based on this information. We appreciate you confirming this via e-mail as we discussed. If you need any additional information, please let me know.

Thanks.

Justin J. Harrison ExxonMobil U.S. Production Safety & Air Compliance CORP-MI-3038 P.O. Box 4697 Houston, TX 77210-4697 Office: 281-654-1127 Fax: 281-654-1147

### E-MAIL FROM Mr. HENRY MADDUX CONCERNING ENDA NGERED SPECIES

----- Forwarded by Justin J Harrison/ U-Houston/ExxonMob il on 06/29/06 08:48 AM -----

Henry_M addux@f ws.gov To <justin.j.ha rrison@exxonmobil.com> 06/29/06 08:39 cc AM Subject Flare-up Near Aneth

Dear Mr. Harrison,

I have reviewed our list of Threat ened and Endangered specie s and critical habitat within your project area near Anet h, Utah. I hav e determined that the reported flare-up has no effect on listed species and their critical habitat. If you have any questions or if additional environmental impacts occur beyond those we have discussed, please contact me at (801)975-3330 x124.

Henry R. Maddux Utah ES Field Supervisor West Valley City, UT

### APPENDIX E

SCREEN3 AND VISCREEN PRINT-OU TS FOR CLASS I AREA IMPACTS**08/03/06 08:51:00**  ***** SCREEN3 MODEL RUN ***** ***** VERSION DATED 96043 *****

**McELMO MAIN FLARE - CHI/Q DISPERSION AT 50 KM., 618.104 SCF/HR, 300 BTU/SCF**

**SIMPLE TERRAIN INPUTS: SOURCE TYPE = FLARE**  **EMISSION RATE (G/S) = 1.00000 FLARE STACK HEIGHT (M) = 59.4500**  **TOT HEAT RLS (CAL/S) = .129887E+08**

**RECEPTOR HEIGHT (M) = .0000 URBAN/RURAL OPTION = RURAL**  **EFF RELEASE HEIGHT (M) = 70.9117 BUILDING HEIGHT (M) = .0000**  **MIN HORIZ BLDG DIM (M) = .0000 MAX HORIZ BLDG DIM (M) = .0000** 

**THE REGULATORY (DEFAULT) MIXING HEIGHT OPTION WAS SELECTED. THE REGULATORY (DEFAULT) ANEMOMETER HEIGHT OF 10.0 METERS WAS ENTERED.** 

**BUOY. FLUX = 215.357 M**4/S**3; MOM. FLUX = 131.320 M**4/S**2.**

***** FULL METEOROLOGY *****

************************************* ***** SCREEN DISCRETE DISTANCES ***** *************************************

***** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES *****

**DIST CONC U10M USTK MIX HT PLUME SIGMA SIGMA (M) (UG/M** 3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DWASH**

**------- ---------- ---- ----- ----- ------ ------ ------ ------ ----- 1100. 1.262 1 1.5 1.7 636.9 635.95 278.55 578.29 NO**  **50000. .2430 5 1.0 2.0 10000.0 212.67 1678.21 156.86 NO**

**DWASH= MEANS NO CALC MADE (CONC = 0.0) DWASH=NO MEANS NO BUILDING DOWNWASH USED**  **DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED**  **DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB**

************************************************ *** SUMMARY OF TERRAIN HEIGHTS ENTERED FOR *** *** SIMPLE ELEVATED TERRAIN PROCEDURE *** ************************************************

**TERRAIN DISTANCE RANGE (M) HT (M) MINIMUM MAXIMUM** 

**------- -------- -------- 0. 1100. --**  **0. 50000. --**

******************************************* ***** SUMMARY OF SCREEN MODEL RESULTS ***** *******************************************

**CALCULATION MAX CONC DIST TO TERRAIN PROCEDURE (UG/M** 3) MAX (M) HT (M)**

**-------------- ----------- ------- ------- SIMPLE TERRAIN 1.262 1100. 0.** 

*******************************************************   REMEMBER TO INCLUDE BACKGROUND CONCENTRATIONS ** ** *********************************************************03/13/08 14:51:31**  ***** SCREEN3 MODEL RUN ***** ***** VERSION DATED 96043 *****

**MCELMO MAIN FLARE - CHI/Q Dispersion at 50 km, 618,104 scf/hr, 443 btu/scf**

**SIMPLE TERRAIN INPUTS: SOURCE TYPE = FLARE**  **EMISSION RATE (G/S) = 1.00000 FLARE STACK HEIGHT (M) = 59.4500**  **TOT HEAT RLS (CAL/S) = .191799E+08 RECEPTOR HEIGHT (M) = .0000**  **URBAN/RURAL OPTION = RURAL EFF RELEASE HEIGHT (M) = 73.2591**  **BUILDING HEIGHT (M) = .0000 MIN HORIZ BLDG DIM (M) = .0000**  **MAX HORIZ BLDG DIM (M) = .0000**

**THE REGULATORY (DEFAULT) MIXING HEIGHT OPTION WAS SELECTED. THE REGULATORY (DEFAULT) ANEMOMETER HEIGHT OF 10.0 METERS WAS ENTERED.** 

**BUOY. FLUX = 318.009 M**4/S**3; MOM. FLUX = 193.915 M**4/S**2.**

***** FULL METEOROLOGY *****

************************************* ***** SCREEN DISCRETE DISTANCES ***** *************************************

***** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES *****

**DIST CONC U10M USTK MIX HT PLUME SIGMA SIGMA (M) (UG/M** 3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DWASH**

**------- ---------- ---- ----- ----- ------ ------ ------ ------ ----- 50000. .2001 5 1.0 2.0 10000.0 234.08 1678.35 158.35 NO** 

**DWASH= MEANS NO CALC MADE (CONC = 0.0) DWASH=NO MEANS NO BUILDING DOWNWASH USED**  **DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED**  **DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB**

******************************************* ***** SUMMARY OF SCREEN MODEL RESULTS ***** *******************************************

**CALCULATION MAX CONC DIST TO TERRAIN PROCEDURE (UG/M** 3) MAX (M) HT (M)**

**-------------- ----------- ------- ------- SIMPLE TERRAIN .2001 50000. 0.** 

*******************************************************   REMEMBER TO INCLUDE BACKGROUND CONCENTRATIONS ** ** *********************************************************03/11/08 15:15:15**  ***** SCREEN3 MODEL RUN ***** ***** VERSION DATED 96043 *****

**McELMO MAIN FLARE - CHI/Q DISPERSION AT 50KM, 618,104 SCF/HR, 538.8 BTU/SCF**

**SIMPLE TERRAIN INPUTS: SOURCE TYPE = FLARE**  **EMISSION RATE (G/S) = 1.00000 FLARE STACK HEIGHT (M) = 59.4500**  **TOT HEAT RLS (CAL/S) = .233276E+08 RECEPTOR HEIGHT (M) = .0000**  **URBAN/RURAL OPTION = RURAL EFF RELEASE HEIGHT (M) = 74.6137**  **BUILDING HEIGHT (M) = .0000 MIN HORIZ BLDG DIM (M) = .0000**  **MAX HORIZ BLDG DIM (M) = .0000**

**THE REGULATORY (DEFAULT) MIXING HEIGHT OPTION WAS SELECTED. THE REGULATORY (DEFAULT) ANEMOMETER HEIGHT OF 10.0 METERS WAS ENTERED.** 

**BUOY. FLUX = 386.779 M**4/S**3; MOM. FLUX = 235.850 M**4/S**2.**

***** FULL METEOROLOGY *****

************************************* ***** SCREEN DISCRETE DISTANCES ***** *************************************

***** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES *****

**DIST CONC U10M USTK MIX HT PLUME SIGMA SIGMA (M) (UG/M** 3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DWASH**

**------- ---------- ---- ----- ----- ------ ------ ------ ------ ----- 50000. .1789 5 1.0 2.0 10000.0 245.91 1678.43 159.25 NO** 

**DWASH= MEANS NO CALC MADE (CONC = 0.0) DWASH=NO MEANS NO BUILDING DOWNWASH USED**  **DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED**  **DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB**

************************************************ *** SUMMARY OF TERRAIN HEIGHTS ENTERED FOR *** *** SIMPLE ELEVATED TERRAIN PROCEDURE *** ************************************************

**TERRAIN DISTANCE RANGE (M) HT (M) MINIMUM MAXIMUM** 

**------- -------- -------- 0. 50000. --** 

******************************************* ***** SUMMARY OF SCREEN MODEL RESULTS ***** *********************************************CALCULATION MAX CONC DIST TO TERRAIN PROCEDURE (UG/M** 3) MAX (M) HT (M)**

**-------------- ----------- ------- ------- SIMPLE TERRAIN .1789 50000. 0.** 

*******************************************************   REMEMBER TO INCLUDE BACKGROUND CONCENTRATIONS ** ** *********************************************************03/11/08 15:08:21**  ***** SCREEN3 MODEL RUN ***** ***** VERSION DATED 96043 *****

**McELMO MAIN FLARE - CHI/Q Dispersion at 50km, 618,104 scf/hr, 682.4 btu/scf**

**SIMPLE TERRAIN INPUTS: SOURCE TYPE = FLARE**  **EMISSION RATE (G/S) = 1.00000 FLARE STACK HEIGHT (M) = 59.4500**  **TOT HEAT RLS (CAL/S) = .295449E+08 RECEPTOR HEIGHT (M) = .0000**  **URBAN/RURAL OPTION = RURAL EFF RELEASE HEIGHT (M) = 76.4268**  **BUILDING HEIGHT (M) = .0000 MIN HORIZ BLDG DIM (M) = .0000**  **MAX HORIZ BLDG DIM (M) = .0000**

**THE REGULATORY (DEFAULT) MIXING HEIGHT OPTION WAS SELECTED. THE REGULATORY (DEFAULT) ANEMOMETER HEIGHT OF 10.0 METERS WAS ENTERED.** 

**BUOY. FLUX = 489.864 M**4/S**3; MOM. FLUX = 298.709 M**4/S**2.**

***** FULL METEOROLOGY *****

************************************* ***** SCREEN DISCRETE DISTANCES ***** *************************************

***** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES *****

**DIST CONC U10M USTK MIX HT PLUME SIGMA SIGMA (M) (UG/M** 3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DWASH**

**------- ---------- ---- ----- ----- ------ ------ ------ ------ ----- 50000. .1541 5 1.0 2.0 10000.0 261.24 1678.55 160.48 NO** 

**DWASH= MEANS NO CALC MADE (CONC = 0.0) DWASH=NO MEANS NO BUILDING DOWNWASH USED**  **DWASH=HS MEANS HUBER-SNYDER DOWNWASH USED DWASH=SS MEANS SCHULMAN-SCIRE DOWNWASH USED**  **DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB**

************************************************ *** SUMMARY OF TERRAIN HEIGHTS ENTERED FOR *** *** SIMPLE ELEVATED TERRAIN PROCEDURE *** ************************************************

**TERRAIN DISTANCE RANGE (M) HT (M) MINIMUM MAXIMUM** 

**------- -------- -------- 0. 50000. --** 

******************************************* ***** SUMMARY OF SCREEN MODEL RESULTS ***** *********************************************CALCULATION MAX CONC DIST TO TERRAIN PROCEDURE (UG/M** 3) MAX (M) HT (M)**

**-------------- ----------- ------- ------- SIMPLE TERRAIN .1541 50000. 0.** 

*******************************************************   REMEMBER TO INCLUDE BACKGROUND CONCENTRATIONS ** ** *********************************************************Visual Effects Screening Analysis for Source: McElmo Main Flare**  **Class I Area: Mesa Verde National Park**

***** User-selected Screening Scenario Results ***** **Input Emissions for**

**Particulates .05 G /S NOx (as NO2) 1.50 G /S**  **Primary NO2 .00 G /S Soot .00 G /S**  **Primary SO4 .00 G /S**

**PARTICLE CHARACTERISTICS Density Diameter** 

**======= ======== Primary Part. 2.5 6**  **Soot 2.0 1 Sulfate 1.5 4** 

**Transport Scenario Specifications:**

**Background Ozone: .04 ppm Background Visual Range: 250.00 km**  **Source-Observer Distance: 60.00 km Min. Source-Class I Distance: 60.00 km**  **Max. Source-Class I Distance: 80.00 km Plume-Source-Observer Angle: 11.25 degrees**  **Stability: 5 Wind Speed: 1.00 m/s** 

**R E S U L T S**

**Asterisks (*) indicate plume impacts that exceed screening criteria**

**Maximum Visual Impacts INSIDE Class I Area Screening Criteria ARE NOT Exceeded**  **Delta E Contrast**

**=========== ============ Backgrnd Theta Azi Distance Alpha Crit Plume Crit Plume** 

**======== ===== === ======== ===== ==== ===== ==== ===== SKY 10. 84. 60.0 84. 2.00 .063 .05 .000**  **SKY 140. 84. 60.0 84. 2.00 .048 .05 -.000 TERRAIN 10. 84. 60.0 84. 2.00 .029 .05 .000**  **TERRAIN 140. 84. 60.0 84. 2.00 .015 .05 .000**

**Maximum Visual Impacts OUTSIDE Class I Area Screening Criteria ARE NOT Exceeded**  **Delta E Contrast**

**=========== ============ Backgrnd Theta Azi Distance Alpha Crit Plume Crit Plume** 

**======== ===== === ======== ===== ==== ===== ==== ===== SKY 10. 0. 1.0 169. 2.00 .692 .05 -.002**  **SKY 140. 0. 1.0 169. 2.00 .419 .05 -.009 TERRAIN 10. 0. 1.0 169. 2.00 .597 .05 .009**  **TERRAIN 140. 0. 1.0 169. 2.00 .396 .05 .006**