Final Conformity Determination for Proposed Carlota Copper Project, Pinal and Gila Counties, Arizona

DEPARTMENT OF AGRICULTURE

Forest Service

Final Conformity Determination for Proposed Carlota Copper

Project, Pinal and Gila Counties, Arizona

AGENCY: Forest Service, USDA.

ACTION: Notice: Final Conformity Determination for the Proposed Carlota

Copper Project, Pinal and Gila Counties, Arizona.

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SUMMARY: In accordance with the federal Conformity Rule (November 30,

1993, 40 CFR 93.150-160), the United States Department of Agriculture,

Forest Service--Tonto National Forest (Tonto NF) has reviewed the air

quality analysis conducted for the proposed Carolta Copper Project. The

project is proposed to be within Hayden/Miami Planning Area and the

Miami Sulfur Dioxide Nonattainment Area, designated nonattainment areas

for particulate matter less than 10 microns in aerodynamic diameter

(PM10) and sulfur dioxide (SO2), respectively.

The Tonto NF's review has been conducted consistent with the

requirements of 40 CFR part 93, Subpart B: ``Determining Conformity of

General Federal Activities to State or Federal Implementation Plans

(SIP)'', issued on November 30, 1993.

The Tonto NF has determined that total annual emissions of

SO2 from the proposed project are less than the de minimis

emission threshold (40 CFR part 93) that triggers the requirement to

conduct a conformity determination.

Annual PM10 emissions have been determined to exceed the

PM10 de minimis threshold and the Tonto NF has prepared a

conformity determination for this pollutant. As per the requirement in

40 CFR 93.153(h)(1), this Federal Register notice lists the proposed

activities that are presumed to conform and the bases for the

presumptions. A comprehensive presentation of the bases for the

conformity presumptions are included in the report, ``Final Conformity

Determination: Carlota Copper Project, Pinal and Gila Counties,

Arizona,'' USDA, Forest Service--Tonto National Forest, July 1997 (the

report). This document is available to the public for reference

purposes.

ADDRESSES: The report, ``Final Conformity Determination: Carlota Copper

Project, Pinal and Gila Counties, Arizona,'' USDA, Forest Service--

Tonto National Forest, Arizona, July 1997, is available for reference

purposes at the following locations: Tonto National Forest Supervisor's

Office, Phoenix, Arizona; Globe Ranger District Office, Globe, Arizona.

FOR FURTHER INFORMATION CONTACT:

Paul M. Stewart, Tonto National Forest, 2324 E. McDowell Road, Phoenix,

AZ 85006, (602) 225-5200.

SUPPLEMENTARY INFORMATION:

I. Background

The Carlota Copper Company has submitted a Plan of Operations

(1992), a subsequent Update to the Plan of Operations (1993), and

numerous letter submittals documenting changes to the Plan of

Operations (as documented in Chapter 2 of the Final Environmental

Impact Statement for the Carlota Copper Project) to the United States

Department of Agriculture, (USDA) Forest Service--Tonto National Forest

(Tonto NF) for the construction, operation, and reclamation of the

Carlota Copper Project (project), a copper mining and processing

operation. The project is designated by rule and regulation as a Class

II minor source to be permitted by the Arizona Department of

Environmental Quality (ADEQ). The proposed project is located on

private land and on lands administered by the Tonto NF. Specifically,

the project is located in Gila and Pinal Counties, approximately 7

miles west of Miami, Arizona.

A portion of the project is proposed to be within the northern part

of an area that has been designated by the United States Environmental

Protection Agency (EPA) as a nonattainment area for the annual 24-hour

National Ambient Air Quality Standard (NAAQS) for particulate matter

less than 10 microns in aerodynamic diameter (PM10). The

first phase of the PM10 nonattainment designation occurred

August 7, 1987, (52 Federal Register (FR) 29383) when EPA identified

and listed the Group I and Group II area in each state. The Hayden/

Miami Planning Area was designated a Group I area. A Group I area is an

area that has been estimated by EPA to have a 95 percent or greater

probability of exceeding the PM10 standards (Hayden

PM10 State Implementation Plan (SIP) p. 14).

On November 15, 1990, EPA designated all Group I areas as

``nonattainment'' for PM10. At the same time, EPA announced

that all areas designated as nonattainment area for PM10

were classified as ``moderate'' nonattainment areas. Therefore, the

Hayden/Miami Planning Area is classified as a moderate nonattainment

area for PM10. A moderate area is a nonattainment area that

the Administrator has determined can practicably attain the NAAQS for

PM10 by the attainment date for moderate areas (as

expeditiously as practicable but no later than the sixth calendar year

after the area's designation as nonattainment). (Clean Air Act, Section

188(a-c)). The Hayden/Miami Planning Area consists of:

Township: T4S, R16E; T5S, R16E; T6S, R16E,

The portion of Township T3S, R16E that does not lie on the

San Carlos Indian Reservation, and

The rectangle formed by, and including Townships: T1N,

R13E; T1N, R15E; T6S, R13E; T6S, R15E.

The portion of the project area that is within the moderate

nonattainment area is in the rectangle formed by the four townships.

Specifically, the project area is located within Township T1N, R13E.

On November 10, 1994, ADEQ petitioned EPA to realign the Hayden/

Miami Planning Area PM10 nonattainment boundary. Based on

topographical and climatological differences, as well as no monitored

exceedances of the PM10 NAAQS in the Miami area, ADEQ

requested that Townships T1N, R13E-R15E and T1S, R13E-R15E be excluded

from the nonattainment area. This area includes the proposed Carlota

Copper Project area. To date, there has been no action by EPA to

realign the Hayden/Miami Planning Area, Therefore, the proposed project

remains within the nonattainment area.

Tonto NF concurs with ADEQ's classification of the proposed Carlota

Copper Project as a Class II minor

[[Page 40793]]

source in a nonattainment area. Consequently, the New Source Review

(NSR) permitting programs (i.e., Prevention of Significant

Deterioration (PSD) review for attainment area and nonattainment area

(NAA) review for nonattainment areas) do not apply. Because the Carlota

Copper Project is not subject to these major source permitting

requirements, the Carlota Copper Project cannot take advantage of the

conformity determination exclusion offered under 40 CFR 93.153(d)(1)

and a formal conformity determination is required.

The area has also been classified as a Priority IA Region (40 CFR

52.121) for sulfur dioxide (SO2). States are required to

prepare and submit a SIP that demonstrates attainment and maintenance

of the NAAQS in Priority I Regions. The Priority IA classification is

for any area that has been designated a Priority I region primarily

because of emissions from a single source. In this case, the

designation is based on copper smelting operations in Miami, Arizona.

The area is in attainment for all other criteria pollutants: carbon

monoxide, nitrogen dioxide, lead, and ozone.

Section 110 of the Clean Air Act requires that the State of Arizona

prepare and submit to the EPA a SIP to reduce particulate emissions to

achieve and maintain attainment of both the SO2 and

PM10 NAAQS. ADEQ has developed a PM10 SIP

designed to reduce and maintain ambient concentrations of

PM10 to levels below the NAAQS for PM10. EPA has

proposed partial approval of the Hayden PM10 SIP. To date,

there has been no final approval of the SIP. ADEQ is in the process of

developing the Miami SO2 SIP.

Due to the proposed location of the project in the nonattainment

area and the Tonto NF's affirmative role as Federal Land Manager, the

Tonto NF has the responsibility under the Clean Air Act section

176(c)(4) (November 15, 1990) to make a determination as to whether the

proposed project conforms with all aspects of the applicable SIP for

the area. The Tonto NF has reviewed the air quality analysis conducted

for this project consistent with the requirements of 40 CFR part 93

Subpart B: ``Determining Conformity of General Federal Actions to State

or Federal Implementation Plans (SIP)'', issued on November 30, 1993.

The Tonto NF has determined that total annual emissions of

SO2 from the project are less than the de minimis emission

threshold (40 CFR 93.153(b)(1)) that triggers the requirement to

conduct a conformity determination. Therefore, although the Miami area

has been designated a nonattainment area for SO2, a

conformity determination for SO2 emissions is not required.

Annual PM10 emissions have been determined to exceed the de

minimis threshold and the Tonto NF has determined that a conformity

determination is required for PM10.

II. Requirements of the Conformity Determination

In the absence of a fully approved PM10 SIP for the

Hayden/Miami planning area, according to 40 CFR 93.151, the federal

conformity regulations contained in 40 CFR part 93 apply to the Carlota

Copper Project.\1\ These regulations require a demonstration that total

direct and indirect emissions from the project will not:

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\1\ Given the receipt of several public comments on the issue of

requirements of a conformity determination, it is important to note

that an increment consumption analysis is not a required portion of

a federal conformity determination. For the Carlota Copper Project,

this position is justified on two levels: (1) The conformity rule

(40 CFR part 93) explicitly lists the requirements of a conformity

determination and does not include an increment consumption analysis

on the list of requirements; and (2) because the proposed Carlota

Copper Project is classified as an Arizona Class II (minor) source

in a nonattainment area, an increment consumption analysis is

expressly not required under state or federal rules and regulations.

Concurrence on this position has been offered by the Tonto NF, ADEQ,

EPA Region IX, and the Pinal County Air Pollution Control District.

As a measure of the significance of impacts from the Carlota Copper

Project, the Tonto NF included an assessment of increment

consumption in the Final Environmental Impact Statement.

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1. Cause or contribute to any new violation of any standard in the

area,

2. Interfere with provisions in the applicable SIP for maintenance

of any standard,

3. Increase the frequency or severity of any existing violation of

any standard in any area, or

4. Delay timely attainment of any standard or any required interim

emission reductions or other milestones in the SIP for purposes of

(a) Demonstration of reasonably further progress (RFP),

(b) Demonstration of attainment, or

(c) Maintenance plan.

The Tonto NF has determined that this Conformity Determination is

to establish through a local modeling analysis that PM10

emissions from Carlota emission sources on private and public lands

will not create any new exceedances of the PM10 NAAQS

(``general'' requirement ``1,'' above). For the reasons stated below,

the activities of the proposed Carlota Copper Project conform to

general requirements 2, 3, and 4.

The proposed SIP only serves to bring ambient PM10

concentrations in the Hayden area to levels that are below the NAAQS.

The PM10 nonattainment designation for the Hayden/Miami

Planning Area is a result of expected exceedances of the

PM10 NAAQS proximate to the coppersmelting activities in the

town of Hayden. As a result, the ``design value'' (i.e., the predicted

ambient level of PM10 upon which the controls in the SIP are

based) pertains to particulate levels in Hayden (not to the proposed

project site). Hayden is located in the southern tip of Gila County,

approximately 25 miles south of the proposed project.

Ambient concentrations monitored in the project area (see the

discussion of background concentrations in the report) and

PM10 monitoring in the town of Miami demonstrate that

exceedances of the NAAQS in the nonattainment area have not occurred

outside of the town of Hayden. Review of the local modeling analysis

for the Carlota Copper Project (discussed in detail in the report)

indicate that particulate impacts in Hayden (25 miles south of the

project) due to emissions from the project are expected to be

negligible (or zero). The proposed project is not expected to interfere

with maintenance of the standard in Hayden and the local modeling

analysis demonstrates protection of the NAAQS in the project area. The

Tonto NF has therefore determined the proposed action to conform with

requirement 2.

Similarly, requirement 3 is met because the project is not expected

to cause any impacts in Hayden, thus emissions from the project will

not increase the frequency or severity of violations of the

PM10 NAAQS that have been monitored in Hayden. There have

been no monitored violations of the PM10 NAAQS in the

proposed project area.

Lastly, requirement 4 is met because there are no interim emission

reductions or other milestones in the proposed SIP that pertain to any

emission sources at the Carlota Copper Project. Particulate emission

control measures in the proposed SIP pertain only to control of

PM10 emissions at two specific copper smelters (and

associated activities) located in Hayden. Any demonstration of

``reasonable further progress,'' attainment, or compliance with a

maintenance plan would only pertain to ambient PM10 levels

in Hayden and/or emission control measures implemented on the subject

emission sources.

III. Conformity Determination Methodology

Local Modeling Analysis. The final Conformity Rule (40 CFR part 93)

specifically allows for the use of a local

[[Page 40794]]

modeling analysis for a conformity determination. 40 CFR

93.158(a)(4)(l) stipulates:

``Where the State agency primarily responsible for the

applicable SIP determines that an area-wide air quality modeling

analysis is not needed, the total of direct and indirect emissions

from the action meet the requirements specified in paragraph (b) of

this section, based on local air quality modeling analysis * * *''

Paragraph (b) (40 CFR 93.158) requires that the local air quality

modeling analysis shows that an action does not cause or contribute to

any new violation of any standard in any area. Paragraph (b) also

requires that a local air quality analysis meet the applicable

requirements of 40 CFR 93.159, Procedures for Conformity Determinations

of General Federal Actions. The applicable requirements of 93.159 are:

The analysis must be based on the latest and most accurate

emission estimation techniques (including estimation of emission

control efficiencies) available for stationary and area sources of

emissions, defined as the latest emission factors specified by EPA in

AP-42 (``Compilation of Emission Factors''), unless more accurate

emission data are available (93.159.b.2) (site-specific parameters are

used when available);

The analysis must be based on the applicable air quality

models, data bases, and other requirements specified in the most recent

version of the ``Guideline on Air Quality Models (Revised)'' (1986)

including supplements (93.159.c); and

The analysis must be based on the total of direct and

indirect emissions from the action and must reflect emission scenarios

that are expected to occur the year during which total emissions are

expected to be the greatest on an annual basis (93.159.d.2).

Emissions. For the purposes of a conformity determination, direct

and indirect emissions are defined as follows (40 CFR 92.152):

Direct Emissions: Those emissions of a criteria pollutant

or its precursors that are caused or initiated by the Federal action

and occur at the same time and place as the action;

Indirect Emissions: Those emissions of a criteria

pollutant or its precursors that:

1. Are caused by the Federal action, but may occur later in time

and/or may be further removed in distance from the action itself but

are still reasonably foreseeable; and

2. The Federal agency can practicably control and will maintain

control over due to a continuing program responsibility of the Federal

agency.

For the Carlota Copper Project, the Tonto NF has determined that

the emissions inventory prepared for the air quality analysis includes

the total of direct and indirect emissions from Carlota sources on

private and Federal lands using the latest emission factors (for

emission estimates and control efficiencies) specified in AP-42 and

site-specific parameters when available (40 CFR 93.159(b)(2)). The

Tonto NF has determined only emissions sources of PM10 at

the proposed project are of concern with regard to PM10

conformity requirements. The basis for designation of the area as

nonattainment was PM10 emissions (not precursors) from

mining activities (associated with smelting activities in Hayden, AZ).

Precursors of PM10 were also not incorporated in the SIP

analysis for the nonattainment area. The Tonto NF maintains that a

conformity determination based on PM10 emissions will be

adequate to assess conformity and to protect the PM10 NAAQS

at the process area boundary.

The local modeling analysis utilized the EPA-approved ISCST3

dispersion model (Version 95200) with the dry deposition algorithm. The

Tonto NF has reviewed the modeling analysis and has determined that the

model has been run according to the most recent modeling guidelines and

supplements.

Emissions from process and non-process sources at the project are

direct emissions under the definition above. The Tonto NF has

determined that the hourly and annual emission estimates prepared for

the air quality analysis are representative of the maximum of

PM10 emission rates expected to occur over the life of the

project. The distribution of emission sources in the modeling analysis

has been assessed by the Tonto NF to be representative of the spatial

extent of the emissions sources that is expected to produce the maximum

off-site PM10 impacts over the life of the project (40 CFR

93.159(d)(2)). Further, the Tonto NF has not identified any other

emissions or emission sources that the Tonto NF can practicably control

or maintain control of due to a continuing program responsibility for

the project. The report includes a detailed description of emission

sources and controls at the project.

Offsets. As an option to a modeling analysis, 40 CFR 93.158 allows

an action to fully offset its emissions within the same nonattainment

area through a revision to the applicable SIP or an equally enforceable

measure that effects emission reductions equal to or greater than the

total of direct and indirect emissions from the action so that there is

no net increase in emissions of that pollutant

(Sec. 93.158(a)(5)(iii)). The Tonto NF has determined that since the

local modeling analysis satisfies the requirements of 40 CFR 93.158(b)

and because there is not a fully approved SIP for the Hayden/Miami

Planning Area that could be revised to include offsets, the local

modeling analysis allowed for in Sec. 93.158(a)(4) is adequate for

determining the conformity of the action.

IV. Presumption of Conformity

The United States Department of Agriculture (USDA) Forest Service--

Tonto National Forest has reviewed the air quality analysis conducted

for the Carlota Copper Project (consistent with the requirement of 40

CFR part 93, ``Determining Conformity of General Federal Actions to

State or Federal Implementation Plans (SIP)'', issued on November 30,

1993).

For purposes of emissions of sulfur dioxide (SO2), the

project is proposed to be located in an area designated as

nonattainment for SO2 (the Miami Sulfur Dioxide

Nonattainment Area) although there is not an approved SO2

SIP for the nonattainment area. The Tonto NF has reviewed the air

quality analysis and determined that predicted direct and indirect

emissions of SO2 are 26 tons per year based on a required

AQCP condition (as issued by ADEQ) to use low sulfur content diesel

fuel. (0.05 percent sulfur by weight) in stationary combustion sources

and the commitment to use low sulfur diesel fuel in all mobile

combustion equipment. This is below the de minimis level of 100 tons

per year for SO2 as defines in the general conformity rule

(40 CFR 93.153). Because projected annual SO2 emissions from

the proposed facility are below the de minimis SO2 level, no

further conformity determination is necessary.

For purposes of emissions of particulate matter with aerodynamic

diameter less than 10 microns (PM10), the project is

proposed to be located in an area designated as a moderate

nonattainment area for PM10 (the Hayden/Miami Planning

Area). The air quality analysis for the project indicates that

predicted direct and indirect emissions of PM10 exceed the

de minimis level for moderate PM10 areas (100 tons per

year). Therefore, the Tonto NF has reviewed the local PM10

emissions modeling analysis for the project and has determined the

following:

The methods for estimating direct and indirect emissions

from the project

[[Page 40795]]

meet the requirements of 40 CFR 93.159. The emissions scenario used in

the air quality analysis is expected to produce the greatest off-site

impacts on a daily and annual basis. (A detailed description of the

emission sources and detailed emissions inventory tables are included

in the report.)

The local PM10 emissions modeling methodology

is appropriate for determining whether emissions from the project will

cause or contribute to any new violation of the PM10

National Ambient Air Quality Standard (NAAQS) and meet the requirements

of 40 CFR 93.159. (A detailed description of the local PM10

emissions modeling methodology is included in the report.)

The results of the modeling analysis using the EPA-

approved ISCST3 dispersion model (Version 95200) with the dry

deposition algorithm predict maximum 24-hour ambient concentrations

(impact plus background) at the process area boundary to be 110.8

g/m3. This is below the 24-hour PM10

NAAQS of 150 g/m3. (A detailed description of the

modeling analysis results and the printouts of the model input and

output files are included in the report.)

The results of the modeling analysis predict the maximum

average annual ambient concentration at the process area boundary to be

36.9 g/m3. This is below the annual PM10

NAAQS STANDARD OF 50 g/m3. \2\

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\2\ Predicted maximum concentrations (impact plus background) at

Top-of-the-World (located within the nonattainment area) area are

20.4 g/m3 for the 24-hour average and 17.3

g/m3 for the annual average.

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The action does not cause or contribute to any new

violation of any standard in any area (40 CFR 93.158(b)(2)(i)).

The action does not increase the frequency or severity of

any existing violation of any standard in any area (40 CFR

93.158(b)(2)(ii)).

The action does not violate any requirements or milestones

in the SIP (no requirements or milestones are applicable to the

project) (40 CFR 93.158(c)).

The Tonto NF has also determined that the planned PM10 controls for

the project are equivalent to Best Available Control Technology (BACT)

for sources of PM10 emissions associated with open-pit

mining operations.

Based on these determinations, the activities at the Carlota Copper

Project is presumed to conform to the applicable conformity

requirements for the project area. The list of activities at the

Carlota Copper Project that are presumed to conform include:

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Process Non-process

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Primary crusher system.............. Topsoil removal.

Conveyor systems.................... Topsoil unloading to stockpiles.

Secondary crusher system............ Blast hole drilling.

Boiler.............................. Blasting.

Back-up generator................... Loading/unloading of ore and mine rock.

Hauling or ore and mine rock.

Combustion emissions from mobile equipment.

Travel of mine equipment other than haul trucks.

Haul road maintenance.

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This presumption of conformity is based on adequate activity

limits, emission limits, emission controls, and monitoring requirements

that have been included in the AQCP No. 071437P0-99 for the Carlota

Copper Project issued by ADEQ. The presumption of conformity assumes

that the requirements in the permit will be adequately enforced by

ADEQ. The Tonto NF lists the following permit requirements (contained

in the Attachment B to the permit) as being critical to the presumption

of conformity of the Carlota Copper Project:

Maximum speed limit of 35 mph for all vehicles and an

average speed for the heavy-duty haul trucks of 15 mph. (Condition

II.D.1)

Unpaved roadway treatment with magnesium chloride, calcium

chloride, or other chemical dust suppressants with equivalent or better

control efficiency in sufficient quantity and frequency to maintain a

ground inventory of 0.25 gallons per square yard. (Condition II.E.2)

Water sprays installed, operated, and maintained

continuously during the times of operation of the primary crusher.

(Condition II.E.2)

Water sprays installed, operated, and maintained

continuously (except as provided by the excess emission rule, A.A.C.

R18-2-306 and 310) during the times of operation of the conveyor

systems, transfer points, process equipment, and storage piles at the

stacker discharge points. (Condition II.E.3)

Baghouse installed and operated on the secondary crusher

and associated vibrating screen. (Condition II.G.1)

A weight rate of mined rock (waste rock and ore combined)

shall not exceed 125,000 tons per 24-hour calendar day and 29 million

tons per year. (Condition III.A)

Burn only diesel no. 2 fuel with a sulfur content of less

than 0.05 percent in the SX/EW tankhouse boiler and backup generator

and the leach pad backup generator. (Condition II, Boiler and Generator

Emissions, C.1)

An ambient PM10 monitor installed, near the

boundary of the mining activity in the general direction of the

Superstition Wilderness, operated on an every-sixth-day schedule, and

maintained in accordance with applicable manufacturer's instructions,

EPA handbooks, and federal requirements (Condition IV.A).

Dated: July 22, 1997.

Charles R. Bazan,

Forest Supervisor.

[FR Doc. 97-20010 Filed 1-29-97; 8:45 am]

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