Prefeasibility Access Road Design-Revised
30
estimate does not account for traffic other than RER vehicles (i.e. there is
existing traffic on the road that is not accounted for in this review).
Table 2, Miller Creek Route, Estimation of Unpaved Road Emissions (attached)
presents a theoretical calculation of emissions that result from RER vehicle traffic
and the corresponding efficiency of water usage assuming the application rates
from Table 1. The estimated uncontrolled PM10 emissions for this road,
assuming only the RER traffic, are 0.19 tons/day. This is based on the estimated
PM10 emission factor of 1.38 lb/vmt.
Assuming 75% control, the application of 64,376 gallons of water per day would
result in PM10 emissions of 0.05 tons/day (reduction of 0.14 tons/day of PM10
compared to no control). This table demonstrates water application beyond
75% is less efficient, and requires more water to control each ton of dust beyond
the 75% control level.
Chemical Suppression
Several chemical suppression techniques are used as binders for unpaved roads
(e.g. calcium chloride, magnesium chloride, organic polymers). This review
assumed use of chloride based applications. Research indicates that good
performance can be obtained with applications between 0.18 gallons/yd2 and
0.55 gallons per yd2, with a standard application rate of 0.3 gallons/yd2 (Best
Practices for Dust Control on Aggregate Roads, Minnesota Department of
Transportation, Local Road Research Board, April 2009). This same research also
indicates that applications will suppress dust for a minimum of 100 days. This
will likely provide a control efficiency at least as good as that for water
suppression discussed above (e.g,. AP-42, Section 13.2.2, Unpaved Roads
(November 2006) estimates a control efficiency of 80% for chemical
suppressants, when applied at intervals of 2 weeks to one month).
The Miller Creek Route has an area of 428,736 yd2. An application rate of 0.3
gallons/yd2 every three months results in chloride use of approximately 514,500
gallons per year.
WARREN PEAK ROUTE
The initial build of the Warren Peak Route will be a combination of 5.5 miles of
unpaved road and 3.9 miles of road paved with asphalt. As the paved road
deteriorates, it would be replaced with aggregate, resulting in a final aggregate
coverage for the entire 9.4 mile route. Alternate analyses were conducted to
evaluate suppression needed for the initial build and the final aggregate
coverage.
