AIR EMISSION PERMIT NO Administrative Amendment IS ISSUED TO. Prospect Foundry, LLC

AIR EMISSION PERMIT NO. 05300099-003 Administrative Amendment IS ISSUED TO Prospect Foundry, LLC PROSPECT FOUNDRY, INC. 1225 Winter Street Northeast Minneapolis, Hennepin County, MN 55413 The emission units, control equipment and emission stacks at the stationary source authorized in this permit amendment are as described in the Permit Applications Table. This permit amendment supersedes Air Emission Permit No. 05300099-002 and authorizes the Permittee to operate the stationary source at the address listed above unless otherwise noted in Table A. The Permittee must comply with all the conditions of the permit. Any changes or modifications to the stationary source must be performed in compliance with Minn. R. 7007.1150 to 7007.1500, and any additions or changes to conditions incorporated into Minnesota s State Implementation Plan (SIP) under 40 CFR 52.1220, designated Title I: SIP for VOC must go through the federal SIP approval process before becoming effective. Terms used in the permit are as defined in the state air pollution control rules unless the term is explicitly defined in the permit. Unless otherwise indicated, all the Minnesota rules cited as the origin of the permit terms are incorporated into the SIP under 40 CFR 52.1220 and as such as are enforceable by U.S. Environmental Protection Agency (EPA) Administrator or citizens under the Clean Air Act. Permit Type: State; Limits to Avoid NSR and Part 70 Operating Permit Issue Date: January 18, 2006 Administrative Amendment Issue Date: July 29, 2008 Expiration Date: Permit does not expire Title I Conditions do not expire. Each new or revised condition designated Title I Condition: SIP for VOC is not effective or enforceable until approved by EPA as a SIP revision under Title I of the Clean Air Act. Jeff J. Smith, Manager Air Quality Permits Section Industrial Division for Brad Moore Commissioner Minnesota Pollution Control Agency TDD (for hearing and speech impaired only): (651) 282-5332 Printed on recycled paper containing at least 10% fibers from paper recycled by consumers

Permit Applications Table Permit Type Application Date Permit Action Total Facility Operating Permit 04/25/2005 001 Administrative Amendment 03/07/2006 & 12/18/2006 002 Administrative Amendment 01/31/2008 003

TABLE OF CONTENTS Notice to the Permittee Permit Shield Facility Description Amendment Description Table A: Limits and Other Requirements Table B: Submittals Appendices Appendix A: not used in this permit Appendix B: Insignificant Activities Appendix C: Site Specific HAP Emission Factors for Metal Processing Appendix D: Facility Description Forms Appendix E: Parameters Relied on in Modeling Appendix F: Bag Leak-Detection System Requirements

NOTICE TO THE PERMITTEE: Your stationary source may be subject to the requirements of the Minnesota Pollution Control Agency s (MPCA) solid waste, hazardous waste, and water quality programs. If you wish to obtain information on these programs, including information on obtaining any required permits, please contact the MPCA general information number at: Metro Area 651-296-6300 Outside Metro Area 1-800-657-3864 TTY 651-282-5332 The rules governing these programs are contained in Minn. R. chs. 7000-7105. Written questions may be sent to: Minnesota Pollution Control Agency, 520 Lafayette Road North, St. Paul, Minnesota 55155-4194. Questions about this air emission permit or about air quality requirements can also be directed to the telephone numbers and address listed above. PERMIT SHIELD: Subject to the limitations in Minn. R. 7007.1800, compliance with the conditions of this permit shall be deemed compliance with the specific provision of the applicable requirement identified in the permit as the basis of each condition. Subject to the limitations of Minn. R. 7007.1800 and 7017.0100, subp. 2, notwithstanding the conditions of this permit specifying compliance practices for applicable requirements, any person (including the Permittee) may also use other credible evidence to establish compliance or noncompliance with applicable requirements.

FACILITY DESCRIPTION: Prospect Foundry operates a gray and ductile iron foundry in Minneapolis, Minnesota. The facility is subject to a 100 ton per year (tpy) major source threshold under New Source Review. Potential total particulate matter (PM), Particulate Matter less than 10 microns (PM 10 ) and Volatile Organic Compounds (VOCs) emissions are greater than major source thresholds under the federal Prevention of Significant Deterioration (PSD) requirements. Potential emissions of Hazardous Air Pollutants (HAPs) are greater than major source thresholds under the federal National Emission Standards for Hazardous Air Pollutants (NESHAPS) requirements. The sources of PM/PM 10 emissions at the facility are sand handling associated with mold and core preparation, metal melting and pouring, casting shakeout and cleaning. The sources of VOCs and HAPs are core making, pouring, cooling and casting shakeout. The facility received a state permit, therefore conditions limiting PM/PM 10 and VOC emissions to less than 100 tpy, and individual/combined HAPs emissions to less than 10/25 tpy were included in the permit. Castings are produced by pouring molten metal into sand molds, with cores used to create hollow internal sections. After the metal has cooled sufficiently, the casting is separated from the mold and undergoes cleaning and finishing techniques as appropriate. Molds and cores provide the exterior (mold) and interior (core) of the casting. Molds are formed around patterns, which are usually made of wood and replicate the exterior of the desired castings. At Prospect, molds are produced from sand. Molds are usually made in two halves. Sand is mixed with clay and water or with chemical binders and then packed or rammed around the pattern to form a mold half. The two halves are joined together to make the mold - a rigid cavity that provides the required shape for the casting. The cores are made from new silica sand by adding resins (binders) or by blowing resinprecoated sand onto a heated shaped surface to solidify sand into a well-defined shape. The finished cores, which can be solid or hollow, are inserted into the mold to provide the internal cavities of the casting before the mold halves are joined. Purchased scrap steel is preheated in an oven prior to being melted. Molten metal is prepared in an electric induction furnace where an electrical current generates a charge that melts purchased scrap metal. A portion of molten metal undergoes metal treatment (addition of magnesium and/or other additives), which converts gray iron into ductile iron. Molten metal is transferred to molds using various types of ladles. Metal is poured into the runner or "gate" (a channel into the mould cavity) until the runner bush is full. The riser provides an additional reservoir of feed metal to release the cavity air and counteract the shrinkage that occurs as the casting begins to cool. When the metal has cooled sufficiently for the casting to hold its shape, it is separated from the mold by a mechanical method referred to as shakeout. After cooling, extraneous pieces of metal (i.e. runners and the risers) are removed and collected for re-melting. A range of finishing processes is usually then undertaken. These may include cleaning to remove residual sand, oxides and surface scale, often by shot or tumble blasting; heat treatment, including annealing, tempering, and quenching (in water or oil) to enhance mechanical properties; and removal of excess metal or surface blemishes (e.g., resulting from incomplete mold closure or burrs left from runner and riser cut-off) by grinding.

Prospect recycles a large proportion of mold and core sand internally for re-use. This involves processing to remove metal and return of the sand to a condition that enables it to be used again for mold or core production. Sand handling processes involve conveying, pneumatic transport, storage, mulling, and mixing of new silica sand and recycled foundry sand. Permit Action No. 001 authorized the replacement of the wet scrubber (CE 001) with a fabric filter baghouse (CE 016), the installation of two new fabric filter baghouses (CE 013 and CE 014) to control emissions from preheating, melting and treatment and four new vent fabric filters (CE 002, CE 010, CE 011 and CE 012) to control emissions from sand handling equipment; and the raising of six stacks (SV 006, SV 019, SV 026, SV 027, SV 028 and SV 048). PERMIT ACTION 002 Permit Action No. 002 authorized the extension of deadlines and clarified technically incorrect information. PERMIT ACTION 003 This permit action changes the name of the owner of Prospect Foundry, Inc. from AmeriCast Technologies, Inc. to Prospect Foundry, LLC.

TABLE A: LIMITS AND OTHER REQUIREMENTS A-1 07/29/08 Facility Name: Permit Number: Prospect Foundry Inc 05300099-003 Table A contains limits and other requirements with which your facility must comply. The limits are located in the first column of the table (What To do). The limits can be emission limits or operational limits. This column also contains the actions that you must take and the records you must keep to show that you are complying with the limits. The second column of Table A (Why to do it) lists the regulatory basis for these limits. Appendices included as conditions of your permit are listed in Table A under total facility requirements. Subject Item: Total Facility MODELING REQUIREMENTS What to do Why to do it Parameters Used in Modeling: The stack heights, emission rates, and other parameters used in modeling done to demonstrate compliance with the National Ambient Air Quality Standards are listed in Appendix E of this permit. The Permittee must submit to the Commissioner for approval, any revisions of these parameters and must wait for written approval before making such changes. Information submitted with a request to make a change must include, but is not limited to: 40 CFR 52.21(d), Minn. R. 7007.3000 and 7009.0020 continued from above - locations, heights and diameters of stacks; - locations and dimensions of nearby buildings; - velocity and temperatures of gases emitted; and, - emission rates of the pollutants being modeling. The plume dispersion characteristics due to the revisions of the information from the proposed change must be equivalent to or better than the dispersion characteristics modeled in Appendix E. The Permittee shall demonstrate this equivalency in their proposal. If the information does not demonstrate equivalent or better dispersion characteristics, or if a conclusion cannot readily be made about the dispersion, the Permittee must remodel. OPERATIONAL REQUIREMENTS Fugitive Emissions Control Plan: The Permittee shall follow the actions and recordkeeping specified in the control plan. The plan may be amended by the Permittee with the Commissioner's approval. If the Commissioner determines that the Permittee is out of compliance with Minn. 7011.0150 or the fugitive emissions control plan, then the Permittee may be required to amend the control plan and/or to install and operate particulate matter ambient monitors as requested by the Commissioner. Circumvention: Do not install or use a device or means that conceals or dilutes emissions, which would otherwise violate a federal or state air pollution control rule, without reducing the total amount of pollutant emitted. Air Pollution Control Equipment: Operate all pollution control equipment whenever the corresponding process equipment and emission units are operated, unless otherwise noted in Table A. Updated Operation and Maintenance Plan: The Permittee shall update their Operation and Maintenance (O & M) plan dated March 10, 2000 to include all new control equipment authorized to be installed by this permit. The Permittee shall retain the plan at the stationary source for all air pollution control equipment. At a minimum, the O & M plan shall identify all air pollution control equipment and control practices and shall include a preventative maintenance program for the equipment and practices, a description of (the minimum but not necessarily the only) corrective actions to be taken to restore the equipment and practices to proper operation to meet applicable permit conditions, a description of the employee training program for proper operation and maintenance of the control equipment and practices, and the records kept to demonstrate plan implementation. The Permittee shall conduct an annual review and, if neccessary, update of their O & M plan following Permit Issuance. Minn. Stat. Section 116.07, subd. 4a; Minn. R. 7007.0100; Minn. R. 7007.0800, subp. 2; Minn. R. 7011.0150; Minn. R. 7009.0020 Minn. R. 7011.0020 Minn. R. 7007.0800, subp. 2; Minn. R. 7007.0800, subp. 16(J) Minn. R. 7007.0800, subp. 14 and Minn. R. 7007.0800, subp. 16(J) Inspections and Maintenance of Air Pollution Control Equipment: The Permittee shall conduct the inspection and maintenance for all pollution control equipment according to the manufacturer's most protective recommendations. Operation Changes: In any shutdown, breakdown, or deviation the Permittee shall immediately take all practical steps to modify operations to reduce the emission of any regulated air pollutant. The Commissioner may require feasible and practical modifications in the operation to reduce emissions of air pollutants. No emissions units that have an unreasonable shutdown or breakdown frequency of process or control equipment shall be permitted to operate. Minn. R. 7007.0800, subp. 14 and Minn. R. 7007.0800, subp. 16(J) Minn. R. 7019.1000, subp. 4

TABLE A: LIMITS AND OTHER REQUIREMENTS A-2 07/29/08 Fugitive Emissions: Do not cause or permit the handling, use, transporting, or storage of any material in a manner which may allow avoidable amounts of particulate matter to become airborne. Comply with all other requirements listed in Minn. R. 7011.0150. Noise: The Permittee shall comply with the noise standards set forth in Minn. R. 7030.0010 to 7030.0080 at all times during the operation of any emission units. This is a state only requirement and is not enforceable by the EPA Administrator or citizens under the Clean Air Act. Inspections: The Permittee shall comply with the inspection procedures and requirements as found in Minn. R. 7007.0800, subp. 9(A). The Permittee shall comply with the General Conditions listed in Minn. R. 7007.0800, subp. 16. PERFORMANCE TESTING Performance Testing: Conduct all performance tests in accordance with Minn. R. ch. 7017 unless otherwise noted in Tables A and/or B. Limits set as a result of a performance test (conducted before or after permit issuance) apply until superseded as specified by Minn. R. 7017.2025 following formal review of a subsequent performance test on the same unit. NEGATIVE PRESSURE DEMONSTRATION Negative Pressure Demonstration: Within 180 days of January 18, 2006, the Permittee shall contract with an independent firm that employs licensed professional engineers and certified industrial hygienists qualified in the design, inspection and evaluation of industrial ventilation and air pollution control systems. The firm shall verify that the ground-level openings in the buildings enclosing the following sources are under negative pressure: 1) GP 003, Sand Handling 2) GP 005, Casting Shakeout 3) GP 006, Grinding, Sawing and Abrasives Blasting Negative Pressure Demonstration Report: Within 360 days of January 18, 2006, the Permittee shall submit a report to the Commissioner which explains the process taken to verify that the ground-level openings in the buildings enclosing the following sources are under negative pressure: 1) GP 003, Sand Handling 2) GP 005, Casting Shakeout 3) GP 006, Grinding, Sawing and Abrasives Blasting MONITORING REQUIREMENTS Monitoring Equipment Calibration: Annually calibrate all required monitoring equipment (any requirements applying to continuous emission monitors are listed separately in this permit). Operation of Monitoring Equipment: Unless otherwise noted in Tables A and/or B monitoring a process or control equipment connected to that process is not necessary during periods when the process is shutdown, or during checks of the monitoring systems, such as calibration checks and zero and span adjustments. If monitoring records are required, they should reflect any such periods of process shutdown or checks of the monitoring system. RECORDKEEPING Recordkeeping: Retain all records at the stationary source for a period of five (5) years from the date of monitoring, sample, measurement, or report. Records which must be retained at this location include all calibration and maintenance records, all original recordings for continuous monitoring instrumentation, and copies of all reports required by the permit. Records must conform to the requirements listed in Minn. R. 7007.0800, subp. 5(A). Recordkeeping: Maintain records describing any insignificant modifications (as required by Minn. R. 7007. 1250, subp. 3) or changes contravening permit terms (as required by Minn. R. 7007.1350 subp. 2), including records of the emissions resulting from those changes. When the Permittee determines that no permit amendment or notification is required prior to making a change, the Permittee must retain records of all calculations required under Minn. R. 7007.1200. For expiring permits, these records shall be kept for a period of five years from the date the change was made or until permit reissuance, whichever is longer. For nonexpiring permits, these records shall be kept for a period of five years from the date that the change was made. The records shall be kept at the stationary source for the current calendar year of operation and may be kept at the stationary source or office of the stationary source for all other years. The records may be maintained in either electronic or paper format. Minn. R. 7011.0150 Minn. R. 7030.0010-7030.0080 Minn. R. 7007.0800, subp. 9(A) Minn. R. 7007.0800, subp. 16 Minn. R. ch. 7017 Minn. R. 7017.2025 Title I Condition: Monitoring to verify negative pressure for hood capture efficiency used in calculations to determine source status under 40 CFR 52.21; Minn. R. 7017.2020, subps. 1(A) and 1(F) continued from above Minn. R. 7007.0800, subp. 4(D) Minn. R. 7007.0800, subp. 4(D) Minn. R. 7007.0800, subp. 5(C) Minn. R. 7007. 0800, subp. 5(B) Minn. R. 7007.1200, subp. 4

TABLE A: LIMITS AND OTHER REQUIREMENTS A-3 07/29/08 REPORTING/SUBMITTALS Shutdown Notifications: Notify the Commissioner at least 24 hours in advance of a planned shutdown of any control equipment or process equipment if the shutdown would cause any increase in the emissions of any regulated air pollutant. If the owner or operator does not have advance knowledge of the shutdown, notification shall be made to the Commissioner as soon as possible after the shutdown. However, notification is not required in the circumstances outlined in Items A, B and C of Minn. R. 7019.1000, subp. 3. At the time of notification, the owner or operator shall inform the Commissioner of the cause of the shutdown and the estimated duration. The owner or operator shall notify the Commissioner when the shutdown is over. Breakdown Notifications: Notify the Commissioner within 24 hours of a breakdown of more than one hour duration of any control equipment or process equipment if the breakdown causes any increase in the emissions of any regulated air pollutant. The 24-hour time period starts when the breakdown was discovered or reasonably should have been discovered by the owner or operator. However, notification is not required in the circumstances outlined in Items A and/or B of Minn. R. 7019.1000, subp. 2. Minn. R. 7019.1000, subp. 3 Minn. R. 7019.1000, subp. 2 At the time of notification or as soon as possible thereafter, the owner or operator shall inform the Commissioner of the cause of the breakdown and the estimated duration. The owner or operator shall notify the Commissioner when the breakdown is over. Notification of Deviations Endangering Human Health or the Environment: As soon Minn. R. 7019.1000, subp. 1 as possible after discovery, notify the Commissioner or the state duty officer, either orally or by facsimile, of any deviation from permit conditions which could endanger human health or the environment. Notification of Deviations Endangering Human Health or the Environment Report: Minn. R. 7019.1000, subp. 1 Within 2 working days of discovery, notify the Commissioner in writing of any deviation from permit conditions which could endanger human health or the environment. Include the following information in this written description: 1. the cause of the deviation; 2. the exact dates of the period of the deviation, if the deviation has been corrected; 3. whether or not the deviation has been corrected; 4. the anticipated time by which the deviation is expected to be corrected, if not yet corrected; and 5. steps taken or planned to reduce, eliminate, and prevent reoccurrence of the deviation. Application for Permit Amendment: If a permit amendment is needed, submit an Minn. R. 7007.1150 through Minn. R. 7007.1500 application in accordance with the requirements of Minn. R. 7007.1150 through Minn. R. 7007.1500. Submittal dates vary, depending on the type of amendment needed. Extension Requests: The Permittee may apply for an Administrative Amendment Minn. R. 7007.1400, subp. 1(H) to extend a deadline in a permit by no more than 120 days, provided the proposed deadline extension meets the requirements of Minn. R. 7007.1400, subp. 1(H). Emission Inventory Report: due 91 days after end of each calendar year following Minn. R. 7019.3000 through Minn. R. 7019.3100 permit issuance (April 1). To be submitted on a form approved by the Commissioner. Emission Fees: due 60 days after receipt of an MPCA bill. Minn. R. 7002.0005 through Minn. R. 7002.0095

TABLE A: LIMITS AND OTHER REQUIREMENTS A-4 07/29/08 Subject Item: Associated Items: GP 001 Scrap Handling and Preheating EU 001 Preheater EU 010 Scrap/Charge Handling EMISSION LIMITS What to do Why to do it Total Particulate Matter: less than or equal to 0.3 grains/dry standard cubic foot of exhaust gas unless required to further reduce emissions to comply with the less stringent limit of either Minn. R. 7011.0730 or Minn. R. 7011.0735. This limit applies to EU 001. Total Particulate Matter: less than or equal to 0.3 grains/dry standard cubic foot of exhaust gas unless required to further reduce emissions to comply with the less stringent limit of either Minn. R. 7011.0730 or Minn. R. 7011.0735. This limit applies to EU 010. Opacity: less than or equal to 20 percent opacity except for one six-minute period per hour of not more than 60 percent opacity. This limit is applicable to EU 001. Opacity: less than or equal to 20 percent. This limit applies to EU 010. OPERATIONAL REQUIREMENTS The Permittee shall vent emissions from GP 001 to CE 014 at all times emission units in GP 001 are in operation. For EU 010, this requirement only applies only to loading of the scrap/charge into the preheater and furnaces. See CE 014 for additional specific operating requirements. Minn. R. 7011.0610, subp. 1(A)(1) Minn. R. 7011.0715, subp. 1(A) Minn. R. 7011.0610, subp. 1(A)(2) Minn. R. 7011.0715, subp. 1(B) Title I Condition: To avoid major source classification under 40 CFR Section 52.21 and Minn. R. 7007.3000; to avoid major source classification under 40 CFR Section 70.2 and Minn. R. 7007.0200

TABLE A: LIMITS AND OTHER REQUIREMENTS A-5 07/29/08 Subject Item: GP 002 Melting and Refining Associated Items: EU 002 Electric Induction Furnace 1 EU 011 Electric Induction Furnace 2 EU 012 Electric Induction Furnace 3 EU 013 Magnesium Treatment OPERATIONAL LIMITS What to do Why to do it Material Usage: less than or equal to 50,000 tons/year using 12-month Rolling Sum of metal melted. This limit applies to EUs 002, 011 and 012 in GP 002. EMISSION LIMITS Total Particulate Matter: less than or equal to 0.3 grains/dry standard cubic foot of exhaust gas unless required to further reduce emissions to comply with the less stringent limit of either Minn. R. 7011.0730 or Minn. R. 7011.0735. This limit is applicable to each unit listed in GP 002. Opacity: less than or equal to 20 percent opacity. This limit is applicable to each unit listed in GP 002. OPERATIONAL REQUIREMENTS The Permittee shall vent emissions from GP 002 to the CE 013 at all times emission units in GP 002 are in operation. See CE 013 for additional specific operating requirements. Covers On Induction Furnaces: The Permittee shall keep the covers on EUs 002, 011 and 012 at all times during melting, except when charging; routine, periodic temperature checks; refining and pouring into ladles. Covers On Transfer Ladles: The Permittee shall keep the covers on the transfer ladles at all times during each magnesium treatment process (EU 013). MONITORING AND RECORDKEEPING REQUIREMENTS Daily Recordkeeping (Metal Melted): Each day, record the total amount of metal melted in EUs 002, 011 and 012. Monthly Recordkeeping (Metal Melted): By the 15th day of each month, calculate and record the total amount of metal melted of EUs 002, 011 and 012 during the previous month, and the total amount of metal melted of EUs 002, 011 and 012 during the previous 12 months (12-month rolling sum). Title I Condition: To avoid major source classification under 40 CFR Section 52.21 and Minn. R. 7007.3000; to avoid major source classification under 40 CFR Section 70.2 and Minn. R. 7007.0200 Minn. R. 7011.0715, subp. 1(A) Minn. R. 7011.0715, subp. 1(B) Title I Condition: To avoid major source classification under 40 CFR Section 52.21 and Minn. R. 7007.3000; to avoid major source classification under 40 CFR Section 70.2 and Minn. R. 7007.0200 Minn. R. 7007.0800, subp. 2 Minn. R. 7007.0800, subp. 2 Title I Condition: To avoid major source classification under 40 CFR Section 52.21 and Minn. R. 7007.3000; to avoid major source classification under 40 CFR Section 70.2 and Minn. R. 7007.0200 Minn. R. 7007.0800, subp. 4 and 5

TABLE A: LIMITS AND OTHER REQUIREMENTS A-6 07/29/08 Subject Item: Associated Items: GP 003 Sand Handling EU 003 Sand Muller A EU 025 Incline Conveyor EU 027 Sorting Conveyor EU 028 Sand Screen EU 029 Sand Elevator EU 030 Plow Conveyor EU 031 Return Sand Tank EU 097 Sand Muller B EU 107 Sand Tank EU 108 Bond Tank EMISSION LIMITS What to do Why to do it Total Particulate Matter: less than or equal to 0.3 grains/dry standard cubic foot of exhaust gas unless required to further reduce emissions to comply with the less stringent limit of either Minn. R. 7011.0730 or Minn. R. 7011.0735. This limit is applicable to each unit listed in GP 003. Opacity: less than or equal to 20 percent opacity. This limit is applicable to each unit listed in GP 003. OPERATIONAL REQUIREMENTS The Permittee shall vent emissions from GP 003 to the control equipment in GP 015 and/or GP 017 at all times emission units in GP 003 are in operation. See GP 015 and GP 017 for additional specific operating requirements. Minn. R. 7011.0715, subp. 1(A) Minn. R. 7011.0715, subp. 1(B) Title I Condition: To avoid major source classification under 40 CFR Section 52.21 and Minn. R. 7007.3000; to avoid major source classification under 40 CFR Section 70.2 and Minn. R. 7007.0200

TABLE A: LIMITS AND OTHER REQUIREMENTS A-7 07/29/08 Subject Item: GP 004 Casting/Pouring/Cooling Associated Items: EU 004 Auto Pouring Line 1 EU 014 Auto Pouring Line 2 EU 015 Auto Pouring Line 3 EU 016 Auto Pouring Line 4 EU 017 Auto Pouring Line 5 EU 018 Floor Casting & Cooling EMISSION LIMITS What to do Why to do it Total Particulate Matter: less than or equal to 0.3 grains/dry standard cubic foot of exhaust gas unless required to further reduce emissions to comply with the less stringent limit of either Minn. R. 7011.0730 or Minn. R. 7011.0735. This limit is applicable to each unit listed in GP 004. Opacity: less than or equal to 20 percent opacity. This limit is applicable to each unit listed in GP 004. Minn. R. 7011.0715, subp. 1(A) Minn. R. 7011.0715, subp. 1(B)

TABLE A: LIMITS AND OTHER REQUIREMENTS A-8 07/29/08 Subject Item: Associated Items: GP 005 Casting Shakeout EU 005 Floor Shakeout EU 019 Long Oscillator (shakeout) EU 020 Auto Line 4 Dump Conveyor EU 021 Auto Line 4 Extension Dump Conveyor EU 022 Auto Line 1 Dump Conveyor EU 023 Auto Line 5 Dump Conveyor EU 024 Auto Line 2 Dump Conveyor EU 026 Lump Breaker EMMISSION LIMITS What to do Why to do it Total Particulate Matter: less than or equal to 0.3 grains/dry standard cubic foot of exhaust gas unless required to further reduce emissions to comply with the less stringent limit of either Minn. R. 7011.0730 or Minn. R. 7011.0735. This limit is applicable to each unit listed in GP 005. Opacity: less than or equal to 20 percent opacity. This limit is applicable to each unit listed in GP 005. OPERATIONAL REQUIREMENTS The Permittee shall vent emissions from GP 005 to the control equipment in GP 015 as shown below at all times the emission units are in operation. See GP 015 for additional specific operating requirements. PRIOR TO CE 001's REPLACEMENT WITH CE 016: Minn. R. 7011.0715, subp. 1(A) Minn. R. 7011.0715, subp. 1(B) Title I Condition: To avoid major source classification under 40 CFR Section 52.21 and Minn. R. 7007.3000; to avoid major source classification under 40 CFR Section 70.2 and Minn. R. 7007.0200 CE 001: EU 005, EU 019 and EU 020 CE 002: EU 026 FOLLOWING CE 001's REPLACEMENT WITH CE 016: CE 002: EU 026 CE 016: EU 005, EU 019 and EU 020

TABLE A: LIMITS AND OTHER REQUIREMENTS A-9 07/29/08 Subject Item: GP 006 Sawing, Grinding and Abrasives Blasting Booths Associated Items: EU 006 Cut-off Saw 1 EU 032 Cut Off Saw 2 EU 033 Cut Off Saw 3 EU 034 Cut Off Saw 4 EU 035 Cut Off Saw 5 EU 036 Swing Saw EU 037 Heavy Portable Grinder 1 EU 038 Heavy Portable Grinder 2 EU 039 Heavy Portable Grinder 3 EU 040 Heavy Portable Grinder 4 EU 041 Heavy Portable Grinder 5 EU 042 Heavy Portable Grinder 6 EU 043 Heavy Portable Grinder 7 EU 044 Swing Grinder EU 045 Big Trimmer EU 046 Hoist Grinder A EU 047 Hoist Grinder B EU 048 Grinder 1 EU 049 Grinder 2 EU 050 Grinder 3 EU 051 Grinder 4 EU 052 Grinder 5 EU 053 Grinder 6 EU 054 Grinder 7 EU 055 Grinder 8 EU 056 Grinder 9 EU 057 Grinder 10 EU 058 Grinder 11 EU 059 Grinder 12 EU 060 Grinder 13 EU 061 Trimmer 1-2 EU 062 Trimmer 3-4 EU 063 Trimmer 5-6 EU 064 Light Portable Grinder 1 EU 065 Light Portable Grinder 2 EU 066 Light Portable Grinder 3 EU 067 Light Portable Grinder 4 EU 068 Light Portable Grinder 5 EU 069 Brinnell Grinder

TABLE A: LIMITS AND OTHER REQUIREMENTS A-10 07/29/08 Associated Items: EU 070 Valve Bench 1 EU 071 Valve Bench 2 EU 072 Valve Bench 3 EU 098 Tumblast Booth 1 EU 099 Tumblast Booth 2 EU 100 Table Blast Booth EU 101 Small Tumblast Booth EMMISSION LIMITS What to do Why to do it Total Particulate Matter: less than or equal to 0.3 grains/dry standard cubic foot of exhaust gas unless required to further reduce emissions to comply with the less stringent limit of either Minn. R. 7011.0730 or Minn. R. 7011.0735. This limit is applicable to each unit listed in GP 006. Opacity: less than or equal to 20 percent opacity. This limit is applicable to each unit listed in GP 006. OPERATIONAL REQUIRMENTS The Permittee shall vent emissions from GP 006 to the control equipment in GP 014 at all times the emission units in GP 006 are in operation. See GP 014 for additional specific operating requirements. Minn. R. 7011.0715, subp. 1(A) Minn. R. 7011.0715, subp. 1(B) Title I Condition: To avoid major source classification under 40 CFR Section 52.21 and Minn. R. 7007.3000; to avoid major source classification under 40 CFR Section 70.2 and Minn. R. 7007.0200

TABLE A: LIMITS AND OTHER REQUIREMENTS A-11 07/29/08 Subject Item: GP 007 Annealing Associated Items: EU 007 Annealing Oven 1 EU 073 Annealing Oven 2 EMMISSION LIMITS What to do Why to do it Total Particulate Matter: less than or equal to 0.3 grains/dry standard cubic foot of exhaust gas unless required to further reduce emissions to comply with the less stringent limit of either Minn. R. 7011.0730 or Minn. R. 7011.0735. This limit is applicable to each unit listed in GP 007. Opacity: less than or equal to 20 percent opacity. This limit is applicable to each unit listed in GP 007. OPERATING REQUIREMENTS Fuels: Limited to natural gas or propane only. This limit is applicable to each unit listed in GP 007. Potential emissions from the annealing ovens are 0.030 lb/hr and 0.015 lb/hr; limit at the stacks where emissions occur, SV 031 and SV 032 is 21.7 lb/hr. Recordkeeping: Record and maintain records of the amounts of each fuel combusted on a monthly basis. These records may consist of purchase records or receipts. Minn. R. 7011.0610, subp. 1(A)(1) Minn. R. 7011.0610, subp. 1(A)(2) Minn. R. 7005.0100, subp. 35a Minn. R. 7007.0800, subp. 4 and 5

TABLE A: LIMITS AND OTHER REQUIREMENTS A-12 07/29/08 Subject Item: GP 008 Core Making Associated Items: EU 008 Core Making Cold Box 1 EU 074 Core Making Cold Box 2 EU 075 Core Making Cold Box 3 EU 076 Core Making Cold Box 4 EU 077 Whirl Air Flow Mixer EU 078 Whirl Air Flow Tank EU 079 Air Set Machine EU 080 Air Set Tank EU 081 Swift-Mul 250 Mixer EU 082 Carver Mixer EU 083 Core Machine 1 EU 084 Core Machine 2 EU 085 Core Machine 3 EU 086 Core Machine 5 EU 087 Core Machine 7 EU 088 Core Machine 8 EU 089 Core Machine 9 EU 090 Core Machine 10 EU 091 Core Machine 11 EU 092 Core Machine 12 EU 093 Core Machine 13 EU 113 Core Machine 14 EMMISSION LIMITS What to do Why to do it Total Particulate Matter: less than or equal to 0.3 grains/dry standard cubic foot of exhaust gas unless required to further reduce emissions to comply with the less stringent limit of either Minn. R. 7011.0730 or Minn. R. 7011.0735. This limit is applicable to each unit listed in GP 008. Opacity: less than or equal to 20 percent opacity. This limit is applicable to each unit listed in GP 008. Minn. R. 7011.0715, subp. 1(A) Minn. R. 7011.0715, subp. 1(B)

TABLE A: LIMITS AND OTHER REQUIREMENTS A-13 07/29/08 Subject Item: Associated Items: GP 009 Core Baking Ovens EU 009 Core Baking Oven EU 094 Tower Oven 1 EU 095 Tower Oven 2 EU 096 Tower Oven 3 EMMISSION LIMITS What to do Why to do it Total Particulate Matter: less than or equal to 0.3 grains/dry standard cubic foot of exhaust gas unless required to further reduce emissions to comply with the less stringent limit of either Minn. R. 7011.0730 or Minn. R. 7011.0735. This limit is applicable to each unit listed in GP 009. Opacity: less than or equal to 20 percent opacity except for one six-minute period per hour of not more than 60 percent opacity. This limit is applicable to each unit listed in GP 009. OPERATING REQUIREMENTS Fuels: Limited to natural gas or propane only. Potential emissions from the core baking ovens are 0.010 lb/hr, 0.010 lb/hr, 0.010 lb/hr and 0.010 lb/hr; limit at the stacks where emissions occur, SV 023, SV 024, SV 025, SV 053 and SV 054 are 5.6 lb/hr, 5.6 lb/hr, 5.6 lb/hr, 3.6 lb/hr and 3.6 lb/hr, respectively. Recordkeeping: Record and maintain records of the amount of each fuel combusted on a monthly basis. These records may consist of purchase records or receipts. Minn. R. 7011.0610, subp. 1(A)(1) Minn. R. 7011.0610, subp. 1(A)(2) Minn. R. 7005.0100, subp. 35a Minn. R. 7007.0800, subp. 4 and 5

TABLE A: LIMITS AND OTHER REQUIREMENTS A-14 07/29/08 Subject Item: GP 010 Core Making Sand Silos Associated Items: EU 109 Uncoated Sand Silo 1 EU 110 Uncoated Sand Silo 2 EU 111 ABC Sand Silo 1 EU 112 ABC Sand Silo 2 EMMISSION LIMITS What to do Why to do it Total Particulate Matter: less than or equal to 0.3 grains/dry standard cubic foot of exhaust gas unless required to further reduce emissions to comply with the less stringent limit of either Minn. R. 7011.0730 or Minn. R. 7011.0735. This limit is applicable to each unit listed in GP 010. Opacity: less than or equal to 20 percent opacity. This limit is applicable to each unit listed in GP 010. OPERATING REQUIREMENTS The Permittee shall vent emissions from GP 010 to the control equipment in GP 017 at all times emission units in GP 010 are in operation. See GP 017 for additional specific operating requirements. STACK HEIGHT REQUIREMENTS Stack Height: The minimum exhaust stack height for the stacks below shall be: SV 019 (CE 011) 45 feet above grade SV 048 (CE 012) 51 feet above grade Minn. R. 7011.0715, subp. 1(A) Minn. R. 7011.0715, subp. 1(B) Title I Condition: To avoid major source classification under 40 CFR Section 52.21 and Minn. R. 7007.3000; to avoid major source classification under 40 CFR Section 70.2 and Minn. R. 7007.0200 40 CFR pt. 50; Minn. Stat. Section 116.07, subds. 4a and 9; Minn. R. 7007.0100, subps. 7A, 7L and 7M; Minn. R. 7007.0800, subps. 1, 2 and 4; and Minn. R. 7009.0010 through 7009.0080 by March 1, 2007. CE 011's exhaust shall vent inside the building near SV 019.

TABLE A: LIMITS AND OTHER REQUIREMENTS A-15 07/29/08 Subject Item: GP 013 Non-Combustion Equipment Subject to HAP Limit Associated Items: EU 002 Electric Induction Furnace 1 EU 004 Auto Pouring Line 1 EU 005 Floor Shakeout EU 008 Core Making Cold Box 1 EU 011 Electric Induction Furnace 2 EU 012 Electric Induction Furnace 3 EU 014 Auto Pouring Line 2 EU 015 Auto Pouring Line 3 EU 016 Auto Pouring Line 4 EU 017 Auto Pouring Line 5 EU 018 Floor Casting & Cooling EU 019 Long Oscillator (shakeout) EU 020 Auto Line 4 Dump Conveyor EU 021 Auto Line 4 Extension Dump Conveyor EU 022 Auto Line 1 Dump Conveyor EU 023 Auto Line 5 Dump Conveyor EU 024 Auto Line 2 Dump Conveyor EU 026 Lump Breaker EU 074 Core Making Cold Box 2 EU 075 Core Making Cold Box 3 EU 076 Core Making Cold Box 4 EU 079 Air Set Machine EU 083 Core Machine 1 EU 084 Core Machine 2 EU 085 Core Machine 3 EU 086 Core Machine 5 EU 087 Core Machine 7 EU 088 Core Machine 8 EU 089 Core Machine 9 EU 090 Core Machine 10 EU 091 Core Machine 11 EU 092 Core Machine 12 EU 093 Core Machine 13 EU 113 Core Machine 14 EMISSION LIMITS What to do Why to do it HAP-Single: less than or equal to 9.0 tons/year using 12-month Rolling Sum, to be calculated as described in the permit by the 15th day of each month for the previous 12-month period. Calculations shall include all HAP emissions from the sources listed in GP 013. Title I Condition: To avoid classification as a major source under 40 CFR Section 63.2; to avoid classification as a major source under 40 CFR Section 70.2 and Minn. R. 7007.0200

TABLE A: LIMITS AND OTHER REQUIREMENTS A-16 07/29/08 HAPs - Total: less than or equal to 22.5 tons/year using 12-month Rolling Sum, to be calculated as described in the permit by the 15th day of each month for the previous 12-month period. Calculations shall include all HAP emissions from the sources listed in GP 013. RECORDKEEPING REQUIREMENTS Title I Condition: To avoid classification as a major source under 40 CFR Section 63.2; to avoid classification as a major source under 40 CFR Section 70.2 and Minn. R. 7007.0200 Daily Recordkeeping: Each day, the Permittee shall record the quantity of each organic material used in core production and maintain a current MSDS for each HAP-containing material used. Maintenance and retention of daily core and mold schedules satisifes this requirement. Material Content: HAP contents in the organic coremaking materials shall be determined by the Material Safety Data Sheet (MSDS) provided by the supplier for each material used. If a material content range is given on the MSDS, the highest number in the range shall be used in all compliance calculations. Other alternative methods approved by the MPCA may be used to determine the HAP contents. The Commissioner reserves the right to require the Permittee to determine the HAP contents of any material, according to EPA or ASTM reference methods. If an EPA or ASTM reference method is used for material content determination, the data obtained shall supersede the MSDS. Monthly Recordkeeping: By the 15th day of each month, the Permittee shall determine and record the following: 1. The quantity of each HAP-containing material used or purchased during the previous month; 2. The quantity of gray and ductile iron poured for the previous month; 3. The individual and combined HAP emissions for the previous month; and, Title I Condition: To avoid classification as a major source under 40 CFR Section 63.2; to avoid classification as a major source under 40 CFR Section 70.2 and Minn. R. 7007.0200 Minn. R. 7007.0800, subp. 4 and 5 Minn. R. 7007.0800, subp. 4 and 5 4. The 12-month rolling sum of individual and combined HAP emissions for the previous month. Single HAP Monthly Calculation: The Permittee shall calculate monthly HAP emissions for each individual HAP as shown below in Equation 1. Minn. R. 7007.0800, subp. 4 and 5 Equation 1: HAP(ti) = HAP(mix) + HAP(mpcs) Where, HAP(ti) = total emissions of the individual HAP for the previous month, in tons HAP(mix) = emissions of the individual HAP from mixing the binder resins and catalysts with sand (tons), calculated as shown in Equation 2 HAP(mpcs) = emissions of the individual HAP from melting, pouring, cooling and shakeout (tons), calculated as shown in Equation 3 Equation 2: Minn. R. 7007.0800, subp. 4 and 5 HAP(mix) = CS x EFvoc x (CR1 / CRt x H1 + CR2 / CRt x H2 + etc.) / 2000 Where, I-HAP(mix) = emissions of the individual HAP from mixing the binder resins and catalysts with sand to make molds or cores during the previous month (tons) CS = quantity of core sand used in each type of process (e.g., Furan No-bake) EFvoc = VOC emission factor specific for the process of the individual HAP for the resin and/or catalyst in each binder formula used during the previous month (percent) (See Note 1) CRi = total quantity of resins and/or catalyst used in the process CR1, CR2... CRn = the quantity of resin and/or catalyst used in each binder formula for molds and cores during the previous month (pound) H1, H2... Hn = the individual HAP content of the resin and/or catalyst in each binder formula used during the previous month (individual HAP, weight percent) Equation 3: Minn. R. 7007.0800, subp. 4 and 5 I-HAP(mpcs) = (MP1 x Hef1 / 2000) + (MP2 x Hef2 / 2000) +... etc. Where, I-HAP(mpcs) = the total emissions of the individual HAP from pouring/cooling and shakeout during the previous month in each type of process (i.e. ductile iron, green sand molds, isocure cores, pouring) (tons), MP1, MP2... MPn = the quantity of metal processed during the previous month (tons) Hef1, Hef2...Hefn = the emission factor for the invidual HAP for each type of process during the previous month (pound/pound) (See Note 2)

TABLE A: LIMITS AND OTHER REQUIREMENTS A-17 07/29/08 Note 1: The VOC emission factors used in Equation 2 (EFvoc) shall be 0.65 lb VOC per ton of core sand for Cold Box process and 1.17 lb VOC per ton of core sand for all other processes using binder resins and/or catalysts. Additions of core making processes that do not belong to No-bake or Cold Box classification will require pre-approval from the MPCA. Any changes in these emission factors shall be submitted to the MPCA with the Annual Compliance Certification. Note 2: The emission factor for the particular HAP shall be the emission factor for the appropriate metal-mold-core combination from Appendix C, developed based on the University of Alamabama-Birmingham's January 1999 report entitled "Ferrous Air Emissions Study." The Permittee shall keep records of the metal throughput, the corresponding emission factors and all supporting documentation. Any changes to the emission factors shall be submitted to the MPCA with the Annual Compliance Certification. Combined HAP Monthly Calculation: The Permittee shall calculate monthly HAP emissions for combined HAPs as shown below in Equation 4. Minn. R. 7007.0800, subp. 4 and 5 Minn. R. 7007.0800, subp. 4 and 5 Minn. R. 7007.0800, subp. 4 and 5 Equation 4: HAP(tc) = the sum of the individual single HAPs (HAP(ti)) for the previous month The 12-month rolling sum of combined HAPs shall be calculated by summing the values of HAP(tc) calculated during each of the pervious months.

TABLE A: LIMITS AND OTHER REQUIREMENTS A-18 07/29/08 Subject Item: Associated Items: GP 014 Fabric Filter Baghouses - Sawing, Grinding and Abrasives Blasting CE 003 Fabric Filter - Low Temperature, i.e., T<180 Degrees F CE 004 Fabric Filter - Low Temperature, i.e., T<180 Degrees F CE 005 Fabric Filter - Low Temperature, i.e., T<180 Degrees F CE 006 Fabric Filter - Low Temperature, i.e., T<180 Degrees F CE 007 Fabric Filter - Low Temperature, i.e., T<180 Degrees F OPERATIONAL REQUIREMENTS What to do Why to do it The Permittee shall operate and maintain each piece of control equipment at all times that any emissions unit listed in GP 006 controlled by the equipment is in operation. The Permittee shall operate and maintain the control equipment in accordance with the most recent Operation and Maintenance (O & M) Plan. The Permittee shall operate and maintain the control equipment such that it achieves a collection efficiency for Particulate Matter < 10 micron: greater than or equal to 99 percent collection efficiency The Permittee shall operate and maintain the control equipment such that it achieves a collection efficiency for Total Particulate Matter: greater than or equal to 99 percent collection efficiency The pressure drop ranges listed below apply unless or until a new range is set pursuant to Minn. R. 7017.2025, subp. 3, based on the values recorded during the most recent MPCA approved performance test where compliance was demonstrated. CE 003 Pressure Drop: greater than or equal to 2 inches of water column and less than or equal to 6 inches of water column CE 004 Pressure Drop: greater than or equal to 5 inches of water column and less than or equal to 7 inches of water column CE 005 Pressure Drop: greater than or equal to 2 inches of water column and less than or equal to 6 inches of water column CE 006 Pressure Drop: greater than or equal to 1 inches of water column and less than or equal to 6 inches of water column CE 007 Pressure Drop: greater than or equal to 2 inches of water column and less than or equal to 6 inches of water column The Permittee shall immediately cease operation of all emission unit(s) connected to a piece of control equipment in GP 014 should the bag leak-detection system indicate a leaking bag or bags. The emission unit(s) shall not be operated again until the neccessary repairs have been made to whichever piece of control equipment in GP 014 had their bag leak-detection system indicate a leaking bag or bags. MONITORING AND RECORDKEEPING REQUIREMENTS Visible Emissions and Pressure Drop: The Permittee shall check each fabric filter stack (listed below) for any visible emissions once each day of operation during daylight hours. The Permittee shall read and record the pressure drop across each fabric filter, once each day of operation, until the installation of the bag leak-detection systems. and Minn. R. 7007.3000 Minn. R. 7007.0800, subps. 4 and 5 Minn. R. 7007.0800, subp. 2 Title I Condition: To avoid major source classification under 40 CFR Section 52.21 and Minn. R. 7007.3000; to avoid major source classification under 40 CFR Section 70.2 and Minn. R. 7007.0200 CE 003: SV 026 CE 004: SV 027 CE 005: SV 028 CE 006: SV 029 CE 007: SV 030

TABLE A: LIMITS AND OTHER REQUIREMENTS A-19 07/29/08 Initial Hood Certification and Evaluation: The control device hoods in GP 014 must conform to the requirements listed in Minn. R. 7011.0070, subp. 1, and the Permittee shall certify this as specified in Minn. R. 7011.0070, subp. 3. The Permittee shall maintain a copy of the evaluation and certification on site. Annual Hood Evaluation: The Permittee shall measure and record at least once every 12 months the fan rotation speed, fan power draw, or face velocity of each hood in GP 014, or other comparable air flow indication method. The Permittee shall maintain a copy of the annual evaluation on site. Monitoring Equipment: The Permittee shall maintain the necessary monitoring equipment for measuring and recording pressure drop as required by this permit until the installation of the bag leak-detection systems. The monitoring equipment must be in use and properly maintained when the monitored fabric filter is in operation. Recordkeeping of Visible Emissions, Pressure Drop and Bag Leak Detection System: The Permittee shall record the time and date of each visible emission inspection, pressure drop reading and bag leak detection system reading, and whether or not any visible emissions were observed, whether or not the observed pressure drop was within the range specified in this permit and whether or not the bag leak detection system indicated that a filter, or filters, require(s) replacement. Minn. R. 7007.0800, subps. 4 and 5 Minn. R. 7007.0800, subps. 4 and 5 Minn. R. 7007.0800, subp. 4 If pressure drop readings vary from past data, the Permittee shall, at a minimum: 1. Inspect the lines going to the magnehelic gauge. 2. Confirm that the cleaning cycles are working properly. 3. Examine the ventilation ducts and pipes for leaks. 4. Inspect the fabric filter bags inside the compartment. Corrective Actions: The Permittee shall take corrective action as soon as possible if any of the following occur: Minn. R. 7007.0800, subp. 4, 5 and 14 - visible emissions are observed; - the recorded pressure drop is outside the required operating range; - the bag leak detection system indicates that a filter, or filters, require(s) replacement; or, - the fabric filters or any of their components are found during the inspections to need repair. Corrective actions shall return the pressure drop to within the permitted range and/or include completion of necessary repairs identified during the inspection, as applicable. Corrective actions include, but are not limited to, those outlined in the O & M Plan for the fabric filters. The Permittee shall keep a record of the type and date of any corrective action taken for each filter. Periodic Inspections: At least once per calendar quarter, or more frequently as required by the manufacturing specifications, the Permittee shall inspect the control equipment components. The Permittee shall maintain a written record of these inspections. MONITORING EQUIPMENT INSTALLATION REQUIREMENTS Bag Leak Detection Systems: The Permittee shall install bag leak detection systems meeting the requirements of Appendix F on CE 003, CE 004, CE 005, CE 006 and CE 007 by March 1, 2007. STACK HEIGHT REQUIREMENTS Stack Height: The minimum exhaust stack heights for the stacks below shall be: SV 026 (CE 003) 45 feet above grade SV 027 (CE 004) 45 feet above grade SV 028 (CE 005) 50 feet above grade Minn. R. 7007.0800, subp. 4, 5 and 14 Minn. R. 7007.0800, subp. 2; Minn. R. 7019.1000, subp. 4 40 CFR pt. 50; Minn. Stat. Section 116.07, subds. 4a and 9; Minn. R. 7007.0100, subps. 7A, 7L and 7M; Minn. R. 7007.0800, subps. 1, 2 and 4; and Minn. R. 7009.0010 through 7009.0080 by March 1, 2007.

TABLE A: LIMITS AND OTHER REQUIREMENTS A-20 07/29/08 Subject Item: Associated Items: GP 015 Control Equipment - Sand Handling and Casting Shakeout CE 001 Wet Scrubber - High Efficiency CE 002 Fabric Filter - Low Temperature, i.e., T<180 Degrees F CE 010 Fabric Filter - Low Temperature, i.e., T<180 Degrees F CE 016 Fabric Filter - Low Temperature, i.e., T<180 Degrees F EQUIPMENT REPLACEMENT What to do Why to do it Should a Performance Test (see CE 001) show that CE 001 is no longer achieving 90 percent control efficiency for PM and PM10, the Permittee is authorized to replace CE 001 with CE 016 within 180 days of the Performance Test showing that CE 001 is no longer achieving 90 percent control efficiency for PM and PM10. CONTROL EQUIPMENT REPLACEMENT NOTIFICATION Notification: due 7 days before Equipment Installation. The written notice can be an e-mail, but must be received by the agency seven working days prior to the replacement of CE 001 with CE 016. OPERATIONAL REQUIREMENTS The Permittee shall operate and maintain each piece of control equipment at all times that any emissions unit listed in GP 003 or GP 005 controlled by the equipment in GP 015 is in operation. The Permittee shall operate and maintain the control equipment in accordance with the most recent Operation and Maintenance (O & M) Plan. Until it is replaced with CE 016, the Permittee shall operate and maintain CE 001 such that it achieves a control efficiency for Total Particulate Matter: greater than or equal to 90 percent control efficiency Until it is replaced with CE 016, the Permittee shall operate and maintain CE 001 such that it achieves a control efficiency for Particulate Matter < 10 micron: greater than or equal to 90 percent control efficiency The Permittee shall operate and maintain CE 002, CE 010 and CE 016 such that they achieve a control efficiency for Particulate Matter < 10 micron: greater than or equal to 99 percent control efficiency The Permittee shall operate and maintain CE 002, CE 010 and CE 016 such that they achieve a control efficiency for Total Particulate Matter: greater than or equal to 99 percent control efficiency The pressure drop ranges listed below apply unless or until a new range is set pursuant to Minn. R. 7017.2025, subp. 3, based on the values recorded during the most recent MPCA approved performance test where compliance was demonstrated. Until it is replaced with CE 016, CE 001's Pressure Drop: greater than or equal to 5 inches of water column and less than or equal to 8 inches of water column CE 002 Pressure Drop: greater than or equal to 2 inches of water column and less than or equal to 6 inches of water column Following its replacement of CE 001, CE 016's Pressure Drop: greater than or equal to 2 inches of water column and less than or equal to 6 inches of water column MONITORING AND RECORDKEEPING REQUIREMENTS Visible Emissions: The Permittee shall check each stack listed below for any visible emissions once each day of operation during daylight hours. CE 001 (until replaced with CE 016): SV 006 CE 002: SV 007 CE 010: SV 066 CE 016 (immediately following the replacement of CE 001): SV 006 Minn. R. 7007.0800, subp. 2 Minn. R. 7007.1150, subp. C(3) and Minn. R. 7007.3000 Minn. R. 7007.0800, subps. 4 and 5 Title I Condition: To avoid major source classification under 40 CFR Section 52.21 and Minn. R. 7007.3000; to avoid major source classification under 40 CFR Section 70.2 and Minn. R. 7007.0200

TABLE A: LIMITS AND OTHER REQUIREMENTS A-21 07/29/08 Pressure Drop: The Permittee shall read and record the pressure drop across each piece of control equipment listed below, once each day of operation until the installation of the bag leak-detection system on CE 016. CE 001 (until replaced with CE 016) CE 002 CE 016 (immediately following the replacement of CE 001) Blacklighting of CE 002: Once per week while in operation, the Permittee shall blacklight the exhaust of CE 002 to determine if there are any leaks. The Permittee shall take corrective action including, but not limited to, neccessary repairs and/or bag replacement of leaking bag(s) immediately upon the blacklighting showing leaks. Initial Hood Certification and Evaluation: The control device hood in GP 015 must conform to the requirements listed in Minn. R. 7011.0070, subp. 1, and the Permittee shall certify this as specified in Minn. R. 7011.0070, subp. 3. The Permittee shall maintain a copy of the evaluation and certification on site. Annual Hood Evaluation: The Permittee shall measure and record at least once every 12 months the fan rotation speed, fan power draw, or face velocity of each hood in GP 015, or other comparable air flow indication method. The Permittee shall maintain a copy of the annual evaluation on site. Monitoring Equipment: The Permittee shall maintain the necessary monitoring equipment for measuring and recording pressure drop as required by this permit until the installation of the bag leak-detection system on CE 016. The monitoring equipment must be in use and properly maintained when the monitored fabric filter is in operation. Recordkeeping of Visible Emissions, Pressure Drop and Bag Leak Detection System: The Permittee shall record the time and date of each visible emission inspection, pressure drop reading and bag leak detection system reading, and whether or not any visible emissions were observed, whether or not the observed pressure drop was within the range specified in this permit and whether or not the bag leak detection system indicated that a filter, or filters, require(s) replacement. Title I Condition: To avoid major source classification under 40 CFR Section 52.21 and Minn. R. 7007.3000; to avoid major source classification under 40 CFR Section 70.2 and Minn. R. 7007.0200 Title I Condition: To avoid major source classification under 40 CFR Section 52.21 and Minn. R. 7007.3000; to avoid major source classification under 40 CFR Section 70.2 and Minn. R. 7007.0200 Minn. R. 7007.0800, subps. 4 and 5 Minn. R. 7007.0800, subps. 4 and 5 Minn. R. 7007.0800, subp. 4 If pressure drop readings on CE 002 and CE 016 vary from past data, the Permittee shall, at a minimum: 1. Inspect the lines going to the magnehelic gauge. 2. Confirm that the cleaning cycles are working properly. 3. Examine the ventilation ducts and pipes for leaks. 4. Inspect the fabric filter bags inside the compartment. Corrective Actions: The Permittee shall take corrective action as soon as possible if any of the following occur: Minn. R. 7007.0800, subp. 4, 5 and 14 - visible emissions are observed; - the recorded pressure drop is outside the required operating range; - the bag leak detection system indicates that a filter, or filters, require(s) replacement; or, - the fabric filter or any of its components are found during the inspections to need repair. Corrective actions shall return the pressure drop to within the permitted range and/or include completion of necessary repairs identified during the inspection, as applicable. Corrective actions include, but are not limited to, those outlined in the O & M Plan for the fabric filters. The Permittee shall keep a record of the type and date of any corrective action taken for each filter. Periodic Inspections: At least once per calendar quarter, or more frequently as required by the manufacturing specifications, the Permittee shall inspect the control equipment components. The Permittee shall maintain a written record of these inspections. MONITORING EQUIPMENT INSTALLATION REQUIREMENTS Bag Leak Detection Systems: By March 1, 2007, the Permittee shall install a bag leak-detection system meeting the requirements of Appendix F on CE 016 within 180 days after replacement of CE 001 with CE 016. STACK HEIGHT REQUIREMENTS Stack Height: The minimum exhaust stack height for SV 006 shall be 25 feet above grade within 180 days after replacement of CE 001 with CE 016. Minn. R. 7007.0800, subp. 4, 5 and 14 Minn. R. 7007.0800, subp. 2; Minn. R. 7019.1000, subp. 4 40 CFR pt. 50; Minn. Stat. Section 116.07, subds. 4a and 9; Minn. R. 7007.0100, subps. 7A, 7L and 7M; Minn. R. 7007.0800, subps. 1, 2 and 4; and Minn. R. 7009.0010 through 7009.0080

TABLE A: LIMITS AND OTHER REQUIREMENTS A-22 07/29/08 Subject Item: Associated Items: GP 017 Vent Fabric Filters CE 011 Fabric Filter - Low Temperature, i.e., T<180 Degrees F CE 012 Fabric Filter - Low Temperature, i.e., T<180 Degrees F OPERATIONAL REQUIREMENTS What to do Why to do it Within 180 days of Permit Issuance, the Permittee shall install CE 011 and CE 012. The Permittee shall operate and maintain each piece of control equipment at all times that any emissions unit listed in GP 017 controlled by the equipment is in operation, in accordance with the most recent Operation and Maintenance (O & M) Plan. The Permittee shall operate and maintain the control equipment such that it achieves a collection efficiency for Particulate Matter < 10 micron: greater than or equal to 99 percent collection efficiency The Permittee shall operate and maintain the control equipment such that it achieves a collection efficiency for Total Particulate Matter: greater than or equal to 99 percent collection efficiency MONITORING AND RECORDKEEPING REQUIREMENTS Visible Emissions: The Permittee shall check each filter (listed below) for any visible emissions one time during each time that sand is loaded. CE 011: SV 019 CE 012: SV 048 Recordkeeping of Visible Emissions: The Permittee shall record the time and date of each visible emission inspection and whether or not any visible emissions were observed. Corrective Actions: The Permittee shall take corrective action as soon as possible if any of the following occur: and Minn. R. 7007.3000 Minn. R. 7007.0800, subp. 4(B) Minn. R. 7007.0800, subp. 4, 5 and 14 - visible emissions are observed; - the filter or any of its components are found during the inspections to need repair. Corrective actions shall include completion of necessary repairs identified during the inspection, as applicable. Corrective actions also include, but are not limited to, those outlined in the O & M Plan for the filters. The Permittee shall keep a record of the type and date of any corrective action taken for each filter. Periodic Inspections: At least once per calendar quarter, or more frequently as required by the manufacturing specifications, the Permittee shall inspect the control equipment components. The Permittee shall maintain a written record of these inspections. Minn. R. 7007.0800, subp. 4, 5 and 14

TABLE A: LIMITS AND OTHER REQUIREMENTS A-23 07/29/08 Facility Name: Permit Number: Prospect Foundry Inc 05300099-003 Subject Item: EU 024 Auto Line 2 Dump Conveyor Associated Items: GP 005 Casting Shakeout GP 013 Non-Combustion Equipment Subject to HAP Limit SV 041 A-2 Line Pouring/Cooling What to do PERFORMANCE TESTING REQUIREMENTS Why to do it Performance Test: due 180 days after 03/29/2007 to measure total particulate matter (PM) from EU 024. Performance Test Notifications and Submittals; Performance Test Notification (written): due 30 days before each Performance Test Performance Test Plan: due 30 days before each Performance Test Performance Test Pre-Test Meeting: due 7 day before each Performance Test Performance Test Report: due 45 days after each Performance Test Performance Test Report - Microfiche Copy or CD: due 105 day after each Performance Test. The Notification, Test Plan, and Test Report may be submitted in alternative format as allowed by Minn. R. 7017.2018. OPERATIONAL REQUIREMENTS Minn. R. 7017.2020, subp. 1 Minn. R. 7017.2030, subp. 1-4; Minn. R. 7017.2018 and Minn. R. 7017.2035, subp. 1-2 Emissions from EU 024: Should the performance test required above show that EU 024 is not meeting the requirements of Minn. R. 7011.0715, subp. 1(A)-1(B), the Permittee shall, within 180 days of Permit Issuance, connect EU 024 to, and vent emissions to, one of the pieces of control equipment listed in GP 015 such that the emission limits in Minn. R. 7011.0715, subp. 1(A)-1(B) are met. Minn. R. 7011.0715, subp. 1(A)-1(B)

TABLE A: LIMITS AND OTHER REQUIREMENTS A-24 07/29/08 Facility Name: Permit Number: Prospect Foundry Inc 05300099-003 Subject Item: CE 001 Wet Scrubber - High Efficiency Associated Items: EU 003 Sand Muller A EU 005 Floor Shakeout EU 019 Long Oscillator (shakeout) EU 020 Auto Line 4 Dump Conveyor EU 097 Sand Muller B GP 015 Control Equipment - Sand Handling and Casting Shakeout NOTIFICATION REQUIREMENTS What to do Why to do it Notification of the date of Equipment Removal/Dismantlement: due 60 days after the Initial Startup of CE 016. PERFORMANCE TESTING REQUIREMENTS Performance Test: due 180 days after 03/29/2007 to measure PM and PM10 control efficiency for the purpose of demonstrating compliance with the limit in GP 015 and determining when replacement with CE 016 is appropriate. Performance Test Notifications and Submittals; Performance Test Notification (written): due 30 days before each Performance Test Performance Test Plan: due 30 days before each Performance Test Performance Test Pre-Test Meeting: due 7 day before each Performance Test Performance Test Report: due 45 days after each Performance Test Performance Test Report - Microfiche Copy or CD: due 105 day after each Performance Test. The Notification, Test Plan, and Test Report may be submitted in alternative format as allowed by Minn. R. 7017.2018. Minn. R. 7007.0800, subp. 2 Minn. R. 7017.2020, subp. 1 Minn. R. 7017.2030, subp. 1-4; Minn. R. 7017.2018 and Minn. R. 7017.2035, subp. 1-2

TABLE A: LIMITS AND OTHER REQUIREMENTS A-25 07/29/08 Facility Name: Permit Number: Prospect Foundry Inc 05300099-003 Subject Item: CE 013 Fabric Filter - Low Temperature, i.e., T<180 Degrees F Associated Items: EU 002 Electric Induction Furnace 1 EU 011 Electric Induction Furnace 2 EU 012 Electric Induction Furnace 3 EU 013 Magnesium Treatment OPERATIONAL REQUIREMENTS What to do Why to do it By March 1, 2007, the Permittee shall install CE 013. The Permittee shall operate and maintain CE 013 at all times that any emissions unit listed in GP 002 controlled by CE 013 is in operation, in accordance with the most recent Operation and Maintenance (O & M) Plan. The Permittee shall operate and maintain the control equipment such that it achieves a collection efficiency for Particulate Matter < 10 micron: greater than or equal to 99 percent collection efficiency The Permittee shall operate and maintain the control equipment such that it achieves a collection efficiency for Total Particulate Matter: greater than or equal to 99 percent collection efficiency The pressure drop range listed below applies unless or until a new range is set pursuant to Minn. R. 7017.2025, subp. 3, based on the values recorded during the most recent MPCA approved performance test where compliance was demonstrated. CE 013. Pressure Drop: greater than or equal to 2 inches of water column and less than or equal to 6 inches of water column MONITORING AND RECORDKEEPING REQUIREMENTS Visible Emissions and Pressure Drop: The Permittee shall check CE 013's stack, SV 067, for any visible emissions once each day of operation during daylight hours. The Permittee shall read and record the pressure drop across the fabric filter, once each day of operation. Monitoring Equipment: The Permittee shall maintain the necessary monitoring equipment for measuring and recording pressure drop as required by this permit. The monitoring equipment must be in use and properly maintained when the monitored fabric filter is in operation. Recordkeeping of Visible Emissions and Pressure Drop: The Permittee shall record the time and date of each visible emission inspection and pressure drop reading, and whether or not any visible emissions were observed and whether or not the observed pressure drop was within the range specified in this permit. Corrective Actions: The Permittee shall take corrective action as soon as possible if any of the following occur: and Minn. R. 7007.3000 Minn. R. 7007.0800, subps. 4 and 5 Minn. R. 7007.0800, subp. 4 Minn. R. 7007.0800, subp. 4, 5 and 14 - visible emissions are observed; - the recorded pressure drop is outside the required operating range; - the fabric filter or any of its components are found during the inspections to need repair. Corrective actions shall return the pressure drop to within the permitted range and/or include completion of necessary repairs identified during the inspection, as applicable. Corrective actions include, but are not limited to, those outlined in the O & M Plan for the fabric filter. The Permittee shall keep a record of the type and date of any corrective action taken for the filter. Periodic Inspections: At least once per calendar quarter, or more frequently as required by the manufacturing specifications, the Permittee shall inspect the control equipment components. The Permittee shall maintain a written record of these inspections. Minn. R. 7007.0800, subp. 4, 5 and 14

TABLE A: LIMITS AND OTHER REQUIREMENTS A-26 07/29/08 Facility Name: Permit Number: Prospect Foundry Inc 05300099-003 Subject Item: CE 014 Fabric Filter - Low Temperature, i.e., T<180 Degrees F Associated Items: EU 001 Preheater EU 010 Scrap/Charge Handling OPERATIONAL REQUIREMENTS What to do Why to do it Within 210 days of Permit Issuance, the Permittee shall install CE 014. The Permittee shall operate and maintain CE 014 at all times that any emissions unit listed in GP 002 controlled by CE 014 is in operation, in accordance with the most recent Operation and Maintenance (O & M) Plan. The Permittee shall operate and maintain the control equipment such that it achieves a collection efficiency for Particulate Matter < 10 micron: greater than or equal to 99 percent collection efficiency The Permittee shall operate and maintain the control equipment such that it achieves a collection efficiency for Total Particulate Matter: greater than or equal to 99 percent collection efficiency The pressure drop range listed below applies unless or until a new range is set pursuant to Minn. R. 7017.2025, subp. 3, based on the values recorded during the most recent MPCA approved performance test where compliance was demonstrated. CE 014 Pressure Drop: greater than or equal to 2 inches of water column and less than or equal to 6 inches of water column MONITORING AND RECORDKEEPING REQUIREMENTS Visible Emissions and Pressure Drop: The Permittee shall check CE 014's stack (SV 068) for any visible emissions once each day of operation during daylight hours. The Permittee shall read and record the pressure drop across the fabric filter, once each day of operation. Monitoring Equipment: The Permittee shall maintain the necessary monitoring equipment for measuring and recording pressure drop as required by this permit. The monitoring equipment must be in use and properly maintained when the monitored fabric filter is in operation. Recordkeeping of Visible Emissions and Pressure Drop: The Permittee shall record the time and date of each visible emission inspection and pressure drop reading, and whether or not any visible emissions were observed and whether or not the observed pressure drop was within the range specified in this permit. Corrective Actions: The Permittee shall take corrective action as soon as possible if any of the following occur: and Minn. R. 7007.3000 Minn. R. 7007.0800, subps. 4 and 5 Minn. R. 7007.0800, subp. 4 Minn. R. 7007.0800, subp. 4, 5 and 14 - visible emissions are observed; - the recorded pressure drop is outside the required operating range; - the fabric filter or any of its components are found during the inspections to need repair. Corrective actions shall return the pressure drop to within the permitted range and/or include completion of necessary repairs identified during the inspection, as applicable. Corrective actions include, but are not limited to, those outlined in the O & M Plan for the fabric filter. The Permittee shall keep a record of the type and date of any corrective action taken for the filter. Periodic Inspections: At least once per calendar quarter, or more frequently as required by the manufacturing specifications, the Permittee shall inspect the control equipment components. The Permittee shall maintain a written record of these inspections. Minn. R. 7007.0800, subp. 4, 5 and 14

TABLE A: LIMITS AND OTHER REQUIREMENTS A-27 07/29/08 Facility Name: Permit Number: Prospect Foundry Inc 05300099-003 Subject Item: CE 016 Fabric Filter - Low Temperature, i.e., T<180 Degrees F Associated Items: EU 003 Sand Muller A EU 005 Floor Shakeout EU 019 Long Oscillator (shakeout) EU 020 Auto Line 4 Dump Conveyor EU 097 Sand Muller B GP 015 Control Equipment - Sand Handling and Casting Shakeout NOTIFICATION REQUIREMENTS What to do Why to do it Notification of the Actual Date of Initial Startup: due 60 days after the Initial Startup of CE 016. Minn. R. 7007.0800, subp. 2

TABLE B: SUBMITTALS Also, where required by an applicable rule or permit condition, send to the Permit Technical Advisor notices of: - accumulated insignificant activities, - installation of control equipment, - replacement of an emissions unit, and - changes that contravene a permit term. B-1 07/29/08 Send submittals that are required to be submitted to the U.S. EPA regional office to: Mr. George Czerniak Air and Radiation Branch EPA Region V 77 West Jackson Boulevard Chicago, Illinois 60604 Each submittal must be postmarked or received by the date specified in the applicable Table. Those submittals required by parts 7007.0100 to 7007.1850 must be certified by a responsible official, defined in Minn. R. 7007.0100, subp. 21. Other submittals shall be certified as appropriate if certification is required by an applicable rule or permit condition. Send submittals that are required by the Acid Rain Program to: U.S. Environmental Protection Agency Clean Air Markets Division 1200 Pennsylvania Avenue NW (6204N) Washington, D.C. 20460 Send any application for a permit or permit amendment to: AQ Permit Technical Advisor Industrial Division Minnesota Pollution Control Agency 520 Lafayette Road North St. Paul, Minnesota 55155-4194 Table B lists most of the submittals required by this permit. Please note that some submittal requirements may appear in Table A or, if applicable, within a compliance schedule located in Table C. Table B is divided into two sections in order to separately list one-time only and recurrent submittal requirements. Unless another person is identified in the applicable Table, send all other submittals to: AQ Compliance Tracking Coordinator Industrial Division Minnesota Pollution Control Agency 520 Lafayette Road North St. Paul, Minnesota 55155-4194

TABLE B: ONE TIME SUBMITTALS OR NOTIFICATIONS B-2 07/29/08 What to send When to send Portion of Facility Affected Application for Permit Reissuance due 180 days before expiration of Existing Total Facility Permit Notification of the Actual Date of Initial Startup due 60 days after Initial Startup of CE 016. CE016 Notification of the date of Equipment due 60 days after Initial Startup of CE 016. CE001 Removal/Dismantlement Notification due 7 days before Equipment Installation The GP015 written notice can be an e-mail, but must be received by the agency seven working days prior to the replacement of CE 001 with CE 016. Updated Operation and Maintenance Plan due 60 days after 01/18/2006 Updated Total Facility Performance Test Report due 360 days after 01/18/2006. The Permittee shall submit a report which explains the process taken to verify that the buildings enclosing the following sources are under negative pressure: Total Facility 1) GP 003, Sand Handling 2) GP 005, Casting Shakeout 3) GP 006, Grinding, Sawing and Abrasives Blasting Performance Test Report due 45 days after Performance Test to measure PM for the purpose of demonstrating compliance with Minn. R. 7011.0715, subp. 1(A) through 1(B). Testing Frequency Plan due 60 days after Initial Performance Test for PM/PM10 control efficiency. The plan shall specify a testing frequency based on the test data and MPCA guidance. Future performance tests based on one-year (12 month), 36 month, and 60 month intervals, or as applicable, shall be required upon written approval of the MPCA. This is being required because periodic testing is warranted but there is insufficient past data to establish a frequency to aid in determining when replacement of CE 001 with CE 016 is appropriate EU024 CE001

TABLE B: RECURRENT SUBMITTALS B-3 07/29/08 What to send When to send Portion of Facility Affected Semiannual Deviations Report due 30 days after end of each calendar Total Facility half-year starting 01/18/2006. The first semiannual report submitted by the Permittee shall cover the calendar half-year in which the permit is issued. The first report of each calendar year covers January 1 - June 30. The second report of each calendar year covers July 1 - December 31. If no deviations have occured, the Permittee shall submit the report stating no deviations. This is a state-only requirement (Minn. R. 7007.0800, subp. 6(A)(2)) and is not enforceable by the Administrator or citizens under the Clean Air Act. Compliance Certification due 31 days after end of each calendar year starting 01/18/2006 (for the previous calendar year). To be submitted on a form approved by the Commissioner, to the Commissioner. This report covers all deviations experienced during the calendar year. This is a state-only requirement (Minn. R. 7007.0800, subp. 6(C)) and is not enforceable by the Administrator or citizens under the Clean Air Act. Total Facility

TECHNICAL SUPPORT DOCUMENT For AIR EMISSION PERMIT NO. 05300099-003 This technical support document is intended for all parties interested in the permit and to meet the requirements that have been set forth by the federal and state regulations (40 CFR 70.7(a)(5) and Minn. R. 7007.0850, subp.1). The purpose of this document is to provide the legal and factual justification for each applicable requirement or policy decision considered in the determination to issue the permit. 1. General Information 1.1 Applicant and Stationary Source Location: Applicant/Address Prospect Foundry LLC 1225 Winter St NE Minneapolis, Minnesota 55413 Contact: Michael Suchy Phone: 612-331-9282 x233 Stationary Source/Address (SIC Code: 3321) 1225 Winter St NE Minneapolis Hennepin County 1.2 Description of the Facility Prospect Foundry operates a gray and ductile iron foundry in Minneapolis, Minnesota. The facility is subject to a 100 ton per year (tpy) major source threshold under New Source Review. Potential total particulate matter (PM), particulate matter less than 10 microns (PM10) and Volatile Organic Compounds (VOCs) emissions are greater than major source thresholds under the federal Prevention of Significant Deterioration (PSD) requirements. Potential emissions of Hazardous Air Pollutants (HAPs) are greater than major source thresholds under the federal National Emission Standards for Hazardous Air Pollutants (NESHAPS) requirements. The sources of PM/PM10 emissions at the facility are sand handling associated with mold and core preparation, metal melting and pouring, casting shakeout and cleaning. The sources of VOCs and HAPs are core making. The facility wishes to receive a state permit; therefore, conditions limiting PM/PM10 and VOC emissions to less than 100 tpy, and individual/combined HAPs emissions to less than 10/25 tpy are included in the permit. Castings are produced by pouring molten metal into sand molds, with cores used to create hollow internal sections. After the metal has cooled sufficiently, the casting is separated from the mold and undergoes cleaning and finishing techniques as appropriate. Molds and cores provide the exterior (mold) and interior (core) of the casting. Molds are formed around patterns, which are usually made of wood and replicate the exterior of the desired castings. At Prospect, molds are produced from sand. Molds are usually made in two halves. Sand is mixed with clay and water or with chemical binders and then packed or rammed around Technical Support Document, Permit Action Number: 05300099-003 Page 1 of 3 Date: 9/10/2008

the pattern to form a mold half. The two halves are joined together to make the mold - a rigid cavity that provides the required shape for the casting. The cores are made from new silica sand by adding resins (binders) or by blowing resin-precoated sand onto a heated shaped surface to solidify sand into a well-defined shape. The finished cores, which can be solid or hollow, are inserted into the mold to provide the internal cavities of the casting before the mold halves are joined, as shown in Figure 1 below. Figure 1 -- Assembled Mold with Core Inserted Ready for Casting Purchased scrap steel is preheated in an oven prior to being melted. Molten metal is prepared in an electric induction furnace where an electrical current generates a charge that melts purchased scrap metal. A portion of molten metal undergoes metal treatment (addition of magnesium and/or other additives), which converts gray iron into ductile iron. Molten metal is transferred to molds using various types of ladles. Metal is poured into the runner or "gate" (a channel into the mold cavity) until the runner bush is full. The riser provides an additional reservoir of feed metal to counteract the shrinkage that occurs as the casting begins to cool, as shown in Figure 2 below. Figure 2 Casting a Sand Mold When the metal has cooled sufficiently for the casting to hold its shape, it is separated from the mold by a mechanical method referred to as shakeout. After cooling, extraneous pieces of metal (i.e. runners and the risers) are removed and collected for re-melting. A range of finishing Technical Support Document, Permit Action Number: 05300099-003 Page 2 of 3 Date: 9/10/2008