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May 1, 2023 nflg 0 Comments

This guidance is intended to help applicants prepare applications and certifications with a reduced amount of effort, yielding clearer and more accurate applications. We hope to steer new applicants around some common mistakes, allowing them to prepare applications which are complete on their first try.

The process involves preparation of facility descriptions, emissions estimates, and completion of some administrative forms. Two passes through the process may be required, calculating emissions and adjusting emissions if any level of significance is exceeded.

The pollutants of concern is particulate matter. If the facility has stationary engines (such as generators), you will also need to address nitrogen oxides (NOx), carbon monoxide (CO), and volatile organic compounds (VOC), particulate matter (PM), and sulfur
dioxide (SO2). These are referred to a “criteria pollutants.” In addition, there may be emissions of hazardous air pollutants (HAPs), primarily formaldehyde.

In general, a rock crushing plant will have a primary crusher, primary screen , secondary crusher(s) and secondary screen(s), and associated conveyors and stockpiles. It may also involve portable generators powered by diesel engines. Emissions of each criteria
pollutant must be less than 100 TPY for the facility to be a minor source. Information as listed here may be attached to the application. Example formats are provided in this document.

Minor source operating permits will require a $500 fee, while a General Operating Permit authorization requires a $150 fee. GOP authorizations for construction require a $400 fee for all minor sources. Permits for specific facilities (everything other than General Operating Permit authorizations) fees depend on the emissions being added. For example, adding emissions of 30 TPY to a facility with current permitted emissions of 50 TPY means the construction permit application fee is $1,000. In a reverse situation
(adding 50 TPY to a facility with 30 TPY permitted emissions), the construction permit fee would be $1,500. Numerous other situations are addressed in the minor source permits rule, OAC 252:100-7, but these situations are not as common.


Provided that 100 TPY of any criteria pollutant is not exceeded, it is recommended that conservatively-high estimates of operating hours and process rates are made. The capacity of the primary crusher is generally known, and therefore the process weight of
the primary crusher, primary conveyor , and primary screen. After this point, it is frequently not easy to tell what process rates will be.

The material processed at the primary crusher and screen will be oversized and undersized. Oversized material is returned to the primary crusher, but the total of new material and returned material cannot exceed the capacity of the primary crusher.

A common source of confusion is in estimating material flows following the primary screen. You may pick reasonable percentages, such as 20% of material from the primary screen being returned to the primary crusher and 80% proceeding to the second crusher, or you may use worst-case flows. Worst-case flows will result in showing the discharges from a unit to be higher than the input. Although that is impossible, it is used only for estimating maximum emissions from each unit.

AP-42 is periodically updated, so limits based on these factors may become out-of-date. It may be to your advantage to include a safety factor on calculations provided that the resultant emissions do not exceed any level of significance such as a regulatory limit or a major source threshold.

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