By Teresa Carson
PORTLAND, Oregon (Reuters) - Teachers and management in Oregon's largest school district reached an agreement in principle on Tuesday on a new contract, averting a strike planned for this week that threatened to disrupt classes for 28,000 students in Portland.
The accord, which followed a 24-hour-long bargaining session overseen by a state mediator, capped 10 months of contentious on-and-off negotiations over staffing levels, wages and other issues.
Rank-and-file instructors in the 2,800-member Portland Teachers Association voted on February 5 to authorize union leaders to call a strike in the event that contract talks collapsed.
The following day, the Portland Teachers Association put the district on formal notice that it intended to begin a walkout February 20 unless the parties clinched a settlement by then.
Early on Tuesday, the two sides announced they had reached a "conceptual" deal and would meet again later in the day to negotiate details of their tentative agreement.
The accord is still subject to approval by the Portland school board and ratification by union members. The planned strike has been suspended pending the outcome of those votes. In the meantime, the district's 78 schools will remain open.
The union and the school district have been at odds over class size, teacher workloads, salary and insurance coverage, but the issue of staffing levels emerged as the chief stumbling block in recent weeks, according to union officials.
The breakthrough came after new state education revenue projections were released last week showing the Portland district stood to gain $4.6 million in additional funds, a windfall that may have helped the two sides close a deal.
Neither party is releasing details of the agreement in principle until after the teachers vote on whether to ratify the new contract.
District officials said the ratification vote could come as soon as in two or three days.
School Superintendent Carole Smith said in a statement that she was "very pleased" that the two sides were able to reach an agreement.
(Editing by Steve Gorman, Cynthia Johnston and Andrew Hay)