Conformity Determination for the Proposed Carlota Copper Project, Pinal and Gila Counties, AZ

DEPARTMENT OF AGRICULTURE

Conformity Determination for the Proposed Carlota Copper Project,

Pinal and Gila Counties, AZ

AGENCY: Forest Service, USDA.

ACTION: Notice of availability.

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SUMMARY: In accordance with the federal Conformity Rule (November 15,

1993, 40 CFR 51.850-51.860), the United States Department of

Agriculture, Forest Service--Tonto National Forest (Tonto NF) has

reviewed the air quality analysis conducted for the proposed Carlota

Copper Project to be located within the Hayden/Miami, Arizona, planning

area that has been designated a nonattainment area for particulate

matter less than 10 microns in aerodynamic diameter (PM10) and

sulfur dioxide (SO2). 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 mission

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 basis for the

presumptions. A comprehensive presentation of the bases for the

conformity presumptions are included in the report, ``Conformity

Determination: Carlota Copper Project,'' USDA, Forest Service--Tonto

National Forest, February, 1996. This document

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is currently available for public review and comment.

DATES: Public comment period ends March 25, 1996.

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

Project,'' USDA, Forest Service--Tonto National Forest, February, 1996,

is available for public review at the following locations: Tonto

National Forest Supervisor's Office, Phoenix, AZ; Globe Ranger District

Office, Globe, AZ. All comments should be in writing and sent to:

Forest Supervisor, Tonto National Forest, 2324 E. McDowell Road,

Phoenix, AZ 85006.

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

Globe Ranger District of 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 proposed

project is located 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 located in 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 and 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 FR 29383) when EPA identified and listed

the Group I and Group II areas 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 Area SIP/PM10, p. 14).

On March 15, 1991, EPA designated all Group I areas as

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

all areas designated as nonattainment 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:

Townships: 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.

The area has also been classified as a Priority 1A Region (40 CFR

52.120) 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 1``A'' classification is for

any area that has been designated a Priority 1 region primarily because

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

based on copper smelting operations in Hayden, Arizona. The area is in

attainment of 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 State Implementation Plan (SIP) to

reduce particulate emissions to achieve and maintain attainment of both

the SO2 and PM10 NAAQS. The Arizona Department of

Environmental Quality (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/Miami PM10 SIP. To date, there has been no final approval

of the SIP. ADEQ is in the process of developing the 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 Conformity Rule (November 15,

1993, CFR 51.850-51.860) 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 Part 93) that triggers the requirement to conduct a conformity

determination. Therefore, although the Hayden 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

The purpose of the conformity analysis is to establish the Carlota

Copper Project's conformity with the Hayden area PM10 SIP, thereby

demonstrating that total direct and indirect emissions from the project

will not:

cause or contribute to any new violation of any standard

in the area,

interfere with provisions in the applicable SIP for

maintenance of any standard,

increase the frequency or severity of any existing

violation of any standard in any area, or

delay timely attainment of any standard or any required

interim emission reductions or other milestones in the SIP for purposes

of

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

(b) a demonstration of attainment, or

(c) a maintenance plan.

For the purposes of a conformity determination, direct and indirect

emissions are defined as follows (40 CFR 93.152):

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 maybe 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

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quality analysis includes the total of direct and indirect emissions

from the project. The Tonto NF has determined that the emissions of

concern with regard to PM10 SIP conformity of the emission sources

at the proposed Carlota Copper Project are restricted to PM10

emissions. 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 SIP conformity and to

protect the PM10 NAAQS at the process area boundary.

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 PM10 emission rates

over the life of the project and that the distribution of emission

sources in the modeling analysis is representative of the spatial

extent of the emissions sources over the life of the project. Further,

the Tonto NF has not identified any other emissions or emissions

sources that the Tonto NF can practicably control or maintain control

of due to a continuing program responsibility at the project. The

report, ``Conformity Determination: Carlota Copper Project,'' USDA,

Forest Service--Tonto National Forest, February 1996, includes a

detailed description of emission sources and controls at the project.

The PM10 nonattainment designation for the Hayden/Miami

planning area is a result of expected exceedances of the PM10

NAAQS proximate to the copper smelting 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, as opposed to the proposed

project site. Furthermore, particulate emission control measures in the

SIP pertain only to control of PM10 emissions at two specific

copper smelters (and associated activities) located in Hayden. Hayden

is located in the southern tip of Gila County, approximately 25 miles

south of the proposed project.

The results of the impact modeling analysis used for this

conformity determination indicate that the Carlota Copper Project is

not expected to cause any increase in ambient PM10 levels in the

Hayden area. The most distant receptor to the south of the project (in

the direction of Hayden) is approximately 6 miles due south of the

center of the proposed process area. The maximum predicted 24-hour and

the annual average PM10 impacts at this receptor are predicted to

be less than 6.8 /m3 and 0.3 /m3,

respectively. Hayden is four times further away from the Carlota Copper

Project that this receptor. The model results suggest that particulate

impacts at Hayden, 25 miles to the south of the project, would be

negligible (or zero). (The report, ``Conformity Determination: Carlota

Copper Project,'' USDA, Forest Service--Tonto National Forest, February

1996, includes a description of modeling approach, presents the results

of the modeling analyses, and includes printouts of the input and

output files of the modeling analyses.)

On November 10, 1994, ADEQ petitioned EPA to re-align the Hayden/

Miami PM10 nonattainment are 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. This

petition, and the history of monitored compliance with the NAAQS in

Miami, underscores the fact that the air quality issues addressed in

the SIP do not pertain to air quality issues in the project area.

Based on this information, the Tonto NF has determined that this

conformity determination is to establish through a local modeling

analysis that PM10 emissions from the proposed project will not

create any new exceedances of the PM10 NAAQS. The other conformity

criteria (listed in the first paragraph of this section) are not

applicable to the Carlota Copper Project due to the conditions of the

nonattainment area, the ambient levels of PM10 at the project

site, and the source specific controls in the SIP.

The final Conformity Rule (40 CFR 93) specifically allows for the

use of a local modeling analysis for a conformity determination. 40 CFR

93.158.a.4.i 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) requires that the local air quality modeling analysis

must show that an action does not cause or contribute to any new

violation of any standard in any area, nor does the action increase the

frequency or severity of any existing violation of any standard in any

area. Paragraph (b) also requires that requirements and milestones in

the SIP must not be violated. (There are no requirements or milestones

that apply to any sources other than the identified smelter sources in

Hayden.) A complete air quality analysis and identification of any

necessary mitigation measures is also required by paragraph (b).

Lastly, paragraph (b) requires that a local air quality analysis

must 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 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):

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).

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 (93.158.a.5.iii). The

Tonto NF has determined that since the local modeling analysis

satisfies the requirements of paragraph (b) and because there is not a

fully approved SIP for the Hayden/Miami are that could be revised to

include offsets, the local modeling analysis allowed for in 93.158.a.4

is adequate for determining the conformity of the action.

III. Presumption of Conformity

The Globe Ranger District of the United States Department of

Agriculture (USDA) Forest Service--Tonto National Forest has reviewed

the air quality

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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, 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. This is below the de minimis level of 100 tons

per year for SO2 as defined in the general conformity rule (40 CFR

93.153). Since the proposed facility conforms with the allowed

emissions limitation, no further conformity determination was deemed

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 of

PM10. 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 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, ``Conformity Determination: Carlota

Copper Project,'' USDA, Forest Service--Tonto National Forest,

February, 1996.)

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, ``Conformity

Determination: Carlota Copper Project,'' USDA, Forest Service--Tonto

National Forest, February, 1996.)

The results of the modeling analysis predict maximum 24-

hour ambient concentrations at the process area boundary to be 110.8

/m3. This is below the 24-hour PM10 NAAQS of 150

/m3. (A detailed description of the modeling analysis

results and the printouts of the model input and output files are

included in the report, ``Conformity Determination: Carlota Copper

Project,'' USDA, Forest Service--Tonto National Forest, February,

1996.)

The results of the modeling analysis predict the maximum

average annual ambient concentration at the process area boundary to be

36.9 /m3. This is below the annual PM10 NAAQS

standard of 50 /m3.

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).

Based on these determinations, the activities at the Carlota Copper

Project is presumed to conform to the applicable SIPs 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 assumes that adequate activity

limits, emission limits, emission controls, and monitoring requirements

will be included in the Air Installation Permit for the Carlota Copper

Project and will be adequately enforced by the issuing agency, the

Arizona Department of Environmental Quality.

Dated: February 13, 1996.

Charles R. Bazan,

Forest Supervisor.

[FR Doc. 96-3804 Filed 2-22-96; 8:45 am]

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