Schneider Logistics will pay $21 million to settle a class-action civil lawsuit brought by about 1,800 Southern California dockworkers who claimed they were not paid properly.

A “notice of proposed settlement” was filed May 13 in the U.S. District Court of Judge Christina Snyder in Los Angeles, and was signed by lawyers for Schneider, Wal-Mart Stores and the plaintiffs. Terms of the settlement were worked out after two days of nonbinding mediation between the parties in San Francisco.

A final arrangement still must be certified by Snyder and probably will take effect at the end of this year or in early 2015, said Theresa Traber, lead attorney for Everado Carrillo and other members of the litigation class.

Schneider Logistics, a division of trucking and logistics company Schneider of Green Bay, Wisconsin, has run Wal-Mart’s Mira Loma distribution center in Riverside County since 2006. Schneider also hired two smaller logistics companies, who in turn hired the dockworkers, or lumpers, who eventually started the legal action.

The case was filed in 2011 based on actions dating to 2001.

Schneider ranks No. 10 on the Transport Topics Top 50 list of logistics companies in the United States, Canada and Mexico.