12. If the 90 percent confidence interval about the mean of my mercury contents is not +/-30 percent of the mean, when must I increase my coal sampling/analysis frequency?

It is presumed (and strongly encouraged) that facilities will be following their coal analyses throughout the reporting quarter and calculating the 90 percent confidence interval about the mean amount of the mercury content of their coal(s) to determine if the mean falls within the +/- 30 percent limit. If, near the end of a reporting quarter, a facility knows that their mean will fall outside this value, they should begin more frequent sampling/analyses immediately upon the start of the new reporting quarter. If the value is close but cannot be determined until all analyses for the quarter are in, the facility should plan to increase the frequency as soon as the final results are in. A facility should not wait until the end of the 45-day submittal period to increase the sampling/analysis frequency.

13. My plant gets 6 or fewer shipments a month and the 90 percent confidence interval about the mean of my mercury contents will exceed +/-30 percent of the mean this quarter, how frequently must I do my coal sampling/analysis next quarter?

Since all plants must sample/analyze every 6th shipment and a minimum of 3 analyses each month, all plants receiving 8 or fewer shipments and not meeting the +/-30 percent of the mean requirement for a quarter will continue having to perform an analysis on 3 shipments. If a plant receiving 8 or fewer shipments cannot meet the meet the +/-30 percent of the mean for a second consecutive quarter, the plant would have to analyze every shipment (with the exception of units receiving less than 3 shipments a month throughout the year who are permitted, for sake of sample consistency, to get more than 1 sample from each shipment to meet the 3 analysis minimum). Analyzing every shipment is the most comprehensive testing that EPA is requiring of any plant under Part II of the Mercury ICR. Even if the plant that starts analyzing every shipment still can't meet +/-30 percent of the mean for a quarter, there will be no additional analyses required beyond this.

To clarify this distinction, EPA's policy on sampling/analyzing scenarios for plants that never meet the +/-30 percent threshold is as follows:

Number of Shipments	1st Quarter 99	2nd Quarter 99	3rd Quarter 99	4th Quarter 99
Plants receiving 3 or fewer shipments	3 samples/analyses per month	Same	Same	Same
Plants receiving 4 to 8 shipments	Minimum 3 samples/analyses per month	Minimum 3 samples/analyses per month	Analyze every shipment	Analyze every shipment
Plants receiving 9 to 17 shipments	Minimum 3 samples/analyses per month	Analyze every 3rd shipment, minimum 3 samples/analyses per month	Analyze every shipment	Analyze every shipment
Plants receiving 18 or greater shipments	Every 6th shipment per month needs to be sampled and analyzed, minimum 3 samples/analyses per month	Every 3rd shipment per month needs to be sampled and analyzed, minimum 3 samples/analyses per month	Analyze every shipment	Analyze every shipment

Note: Plants that receive coal by conveyor, intermittently, should review the definition of a shipment in the Part I FAQ and then follow the appropriate table entry above. For plants that receive coal by conveyors operating continuously, and now performing 3 samples/analyses per month (one every 10th day) and failing the +/- 30% value, should perform 6 samples/analyses per month in the next quarter (one every 5th day). If the same plant can not meet the +/- 30% value the next quarter, then 10 samples/analyses should be performed (one every 3 days), and finally 15 samples/analyses (one every other day)?