Bagdad Mine Stockpile Extension
Freeport-McMoRan Bagdad Inc.
2.3 Air Quality Management (Mine Dust Control)
The fugitive dust emissions from open areas, roadways, storage piles, and material handling areas, including the Stockpile, proposed Stockpile extension, and haul roads, are regulated under the current Bagdad Mine air quality permit. The air quality permit requires:
• Opacity of emission from fugitive dust non-point sources must not exceed 40 percent; and
• Opacity of emission from fugitive dust point sources must not exceed 20 percent.
In addition, the air quality permit requires that FMBI use reasonable precautions to prevent excessive amounts of particulate matter from becoming airborne, such as watering or applying approved dust suppressants or adhesive soil stabilizers to control visible emissions from haul roads and storage piles.
While water generally is applied for dust control, dust suppressants or adhesive soil stabilizers may be used on the Stockpile and proposed Stockpile extension. Dust suppressant products are designed to form a hard crust that can withstand vehicle traffic on unpaved roads or elevated winds on bulk storage piles. Surfactants are non-petroleum based organics which, when added to water, reduce surface tension for better water penetration into subsurface soil layers before or during active earthmoving. Adhesive soil stabilizers may include synthetic polymer or organic dust suppressants to bind soil particles together and generally can be used to form a firm, stabilizing crust. Typical dust suppressant products may include the following, or similar, products:
• Chem-Loc 101 (surfactant)
• Enviro RoadMoisture 2.5 (surfactant)
• Durasoil® (synthetic organic)
• Jet-Dry (surfactant)
• Haul Road Dust Control (surfactant)
• EnviroKleen (synthetic polymer)
The air quality permit requires monthly, visual surveys of emissions by a certified observer and specifies sampling and reporting requirements. In addition, posted truck speeds are limited to 35 miles per hour, and trucks typically travel at substantially lower speeds, particularly when loaded and/or traveling uphill.