R307-309-5. General Requirements for Fugitive Dust

  (1) Except as provided in R307-309-5(3), opacity caused by fugitive dust shall not exceed:

  (a) 10% at the property boundary; and

  (b) 20% on site

  (2) Any person owning or operating a new or existing source of fugitive dust one-quarter acre or greater in size shall submit a fugitive dust control plan to the director in accordance with R307-309-6.

  (3) Opacity in R307-309-5(1) shall not apply when the wind speed exceeds 25 miles per hour if the owner or operator has implemented, and continues to implement, the accepted fugitive dust control plan in R307-309-6 and administers one or more of the following contingency measures:

  (a) Pre-event watering;

  (b) Hourly watering;

  (c) Additional chemical stabilization;

  (d) Cease or reduce fugitive dust producing operations to the extent practicable.

  (4) Wind speed shall be measured by an anemometer.

  (5) Opacity observations of fugitive dust from any source shall be measured at the densest point of the plume.

  (a) For mobile sources, visible emissions shall be measured at a point not less than 1/2 vehicle length behind the vehicle and not less than 1/2 the height of the vehicle.

  (b) Opacity observations of emissions from stationary sources shall be measured in accordance with EPA Method 9.

  (c) For intermittent sources, opacity observations shall be conducted using Method 9; however, the requirement for observations to be made at 15 second intervals over a six-minute period shall not apply. The number of observations and the time period shall be determined by the length of the intermittent or mobile source operation.