The South Carolina Ports Authority (SCPA) yesterday announced plans to purchase the former WestRock paper mill site in North Charleston to further expand capacity at the Port of Charleston.The 280-acre industrial waterfront property is adjacent to North Charleston Terminal, offering a natural extension of the container terminal that will enable the port to handle more cargo for port-dependent businesses, SCPA officials said in a press release. The additional land will expand the terminal’s capacity to 5 million containers, and create 5,000 feet of linear berth space for container ships and about 400 acres of terminal space for cargo.