## U.S. Environmental Protection Agency Applicability Determination Index

Control Number: 9600081

Category: NSPS
EPA Office: METD
Date: 11/30/1994
Title: Various Subpart P Issues; Opacity Recipient: McKaughan, Colleen
Author: Rasnic, John

Subparts: Part 60, A, General Provisions Part 60, P, Primary Copper Smelters

References: 60.11(e) 60.11(g)
60.161
60.163
60.164

Abstract:

Q: What is the scope of the term smelting furnace?

A: "Smelting furnace" is defined in section 60.161(f) as "any vessel in which the smelting of copper sulfide ore concentrates or calcines is performed and in which the heat necessary for smelting is provided by an electric current . . ." The term smelting is defined as "processing techniques for the melting of a copper sulfide ore concentrate or calcine charge leading to the formation of separate layers of molten slag, molten copper, and/or copper matte."

Q: What are the emissions points where the NSPS opacity standards in section 40.164 apply?

A: Any point where emissions are vented from the affected facility, which would include a vent fume stack that allows bypass of the acid plant.

Q: What are the requirements when gas streams from NSPS and non-NSPS sources are comingled?

A: It is policy that when gas streams are combined monitoring may be performed prior to when the gas streams are combined. If that is not feasible, the emissions can be measured at the stack. However, the stack must meet the lowest standard that applies to any affected facility that is routed to that stack.

Q: What is the procedure for reviewing adjustments to the opacity standard?

A: The Region reviews the request, but only headquarters has the authority to approve.

Letter:

MEMORANDUM

SUBJECT: Applicability Determination for a NSPS Subpart P Copper Smelter at Cyprus Miami Mining Corporation, Miami, Arizona

FROM: John B. Rasnic, Director Manufacturing, Energy, and Transportation Division Office of Compliance

TO: Collen McKaughan, Chief Air Compliance Branch Region IX

This memorandum is in response to the questions regarding Cyprus Miami Mining Corporation's, Miami, Arizona copper smelters. The four questions were as follows: What is the scope of the term smelting furnace? What are the emissions points where the NSPS opacity standards applies? What are the requirements when gas streams from NSPS and non-NSPS sources are comingled; and what is the procedure for reviewing adjustments to the opacity standard?

A "smelting furnace" is defined in section 60.161(f) as "any vessel in which the smelting of copper sulfide ore concentrates or calcines is performed and in which the heat necessary for smelting is provided by an electric current . . ." The term smelting is defined as "processing techniques for the melting of a copper sulfide ore concentrate or calcine charge leading to the formation of separate layers of molten slag, molten copper, and/or copper matte." The electric furnace that Cyprus Miami has labeled as "slag cleaning only" is separating slag and copper matte. This process is smelting as defined by NSPS subpart P: Primary Copper Smelters. The process is performed in an electric furnace which is included in the definition of smelting furnace. Therefore, if the electric furnace at Cyprus Miami was constructed, reconstructed, or modified after October 16, 1974 it is an affected facility. Cyprus Miami's other smelting furnace, the IsaSmelt, is a separate affected facility.

In a telephone conversation with David Carlson, of your office, he indicated that the electric furnace was constructed prior to the applicability date. We cannot address the issue of whether the electric furnace is subject to NSPS subpart P under the reconstruction or modification provisions because information on this point was not available from the Region.

The emissions from the electric furnace (if it is determined to be subject) and the IsaSmelt are subject to a sulfur dioxide standard of 0.065 percent by volume (60.163(a)) and a 20% opacity limit (60.164(b)). Section 60.164(b) states that "no owner or operator subject to the provisions of this subpart shall cause to be discharged into the atmosphere from any affected facility that uses a sulfuric acid plant to comply with the standard set forth in section 60.163, any visible emissions which exhibit greater than 20 percent opacity."

EPA document EPA 450/3-83-018a; Review of New Source Performance Standards for Primary Copper Smelters explains that the regulation was designed to control emissions to a level equivalent to using a double contact acid plant. Cyprus Miami uses an acid plant to control emissions and is subject to the opacity standard in section 60.164(b). The phrase "discharged into the atmosphere from any affected facility" includes any emission point, not just the emissions from the acid plant tail stack. Therefore, the emissions from the vent fume stack that bypass the acid plant are also subject to the 20 percent opacity standard.

The monitoring of combined or divided gas streams is addressed in section 60.11(g) of the general provisions. This paragraph states that when different standards apply, each effluent must be monitored before they are co-mingled. If the emissions from the affected facility are vented to the atmosphere through more than one point, each emission point must be monitored.

It has been our policy that when gas streams are combined monitoring may be performed prior to when the gas streams are combined. If that is not feasible, the emissions can be measured at the stack. However, the stack must meet the lowest standard that applies to any affected facility that is routed to that stack. Therefore, if the plant is designed such that measurements can not be obtained after the affected facility and before emissions are combined, the most restrictive standard applies at all points where emissions from the affected facility are vented to the atmosphere.

If Cyprus Miami has combined emissions from NSPS and non-NSPS sources and can only measure emissions at the stack, the stack is subject to the 0.065% by volume standard for sulfur dioxide and a 20 percent opacity limit.

In regards to an alternative opacity standard, under section 60.11(e)(6) a source may request an opacity standard specific to that plant. To make such a request the source must show compliance with all applicable standards, but fail to meet the opacity standard. The performance test and opacity readings must be taken at the same time, and the source must demonstrate that it has properly maintained and operated control equipment and has taken all practical means to reduce the opacity.

In the second part of this question you refer to applying for a modification; I assume you mean applying for an alternative opacity standard. If the source wishes to apply for an alternative opacity standard, the request should be sent to the Region. The Region would provide a technical review, and if the source has provided adequate documentation that it has met the requirements set forth and the request is approvable, the Region drafts a Federal Register notice to approve the alternative limit. The draft approval package should be forwarded to the Manufacturing Branch of the Office of Compliance. The authority to approve alternative emissions standards is at the headquarters level; it has not been delegated to the Regional or state level.

If you have any questions regarding this determination please contact Bob Fentress at (202)564-7023, Belinda Breidenbach at (202)564-7019, or in her absence, Sally Mitoff at (202)564-7012.