State Representative Erin Zwiener (D-Driftwood) was one of nine representatives and public members appointed to the House Interim Study Committee on Aggregate Production Operations (APOs) by Speaker Dennis Bonnen (R-Angleton) on Tuesday, December 10. APOs, which include concrete batch plants and rock quarries, are having a dramatic impact on the environment and surrounding communities in rapidly growing counties like Hays and Blanco. Rep.