Opponents of a proposed petroleum pipeline are lining up in advance of a public hearing set for 5 p.m. Tuesday at the Richmond Hill City Center. Environmental groups are calling for a rally at noon Saturday at Forsyth Park in Savannah and could turn out in force at Tuesday’s meeting, which is the only one being held by the Georgia Department of Transportation. Some have asked the DOT to add a second public hearing in the Augusta area to give residents there an opportunity to raise concerns.