Dmitry-David Tartakovsky, Ph.D.
This study evaluates different combinations of emission factors for surface phosphate mining by comparing AERMOD and CALPUFF dispersion modeling results to concentrations measured in the Khneifiss open pit phosphate mine, Syria (Othman and Al-Masri, 2007) and around Al-Hassa and Al-Abyad open pit phosphate mines, Jordan (Hamaiedth and El-Hasan, 2011) — the only works that reports measured TSP or PM10 and PM2.5 concentrations around open pit phosphate mines.
Our results show that using the USEPA AP 42 emission factors for both phosphate transfer and unpaved roads results in modeled ambient concentrations that were in better agreement with field observations.
Applying emission factors that were developed for buldozing and grading in surface coal mines for surface phosphate mining yields underestimated ambient TSP concentrations, especially within the mining area (due to lack of data similar conclusions for PM2.5 and PM10 cannot be drawn). Due to lack of data the proportionality coefficient is uncertain. For the scenarios studied in this work, a factor of 20 was applied for the emission factor from buldozing and grading in surface coal mines.
Differences between estimated ambient TSP concentrations based on the EPA or the NPI emission factors due to wind erosion were found to be small.
The results may indicate that the “net” mining operations (buldozing, grading and draglines operations) contribute less to the surrounding PM concentrations than other operations in surface phosphate mines (e.g. phosphate transportation and processing).
The planned second phase (using Monte Carlo simulations or Latin Hypercube Sampling) is expected to update these preliminary conclusions.