Environmental groups plan to deliver 3,500 petitions to Gov. Jay Nixon today, asking his administration to halt permitting for coal ash landfills in the state’s floodplains. The Sierra Club and the Labadie Environmental Organization are fighting Ameren Missouri’s plans for a coal ash landfill in Franklin County along the Missouri River. They plan to ask Nixon’s administration to support stronger rules on the storage and disposal of coal ash waste, which they say has not been properly monitored and is contaminating state waters. Ameren counters that building elsewhere would cost tens of millions of dollars more. The utility says the landfill is lined to prevent seepage and the ash is mixed with clay so it hardens and won’t wash away. If the state grants Ameren a permit, the utility hopes to begin construction this summer and finish by 2016.