Phelps Dodge Corp. agreed yesterday to a 10-day shutdown of its Morenci mine and smelter as 1,000 striking copper workers and supporters massed around its main entrance, armed with baseball bats, ax handles and pipes.

The company and a committee representing the 12 striking unions will meet as soon as possible under a federal mediator, said Jerry Spreitzer, president of Machinists Local 1132.

The agreement, after two days of tension here and at the company mine in Ajo, came during a 75-minute meeting arranged after Gov. Bruce Babbitt asked each side to "take one step back from the precipice of violence . . . . "

Anger had increased since Friday's announcement that the company would seek to fill about 1,500 positions. About 2,300 have been on strike and, according to the company, about 700 union-represented workers have crossed picket lines.

In a written statement, Phelps Dodge said, "The company agrees to remove all employes from the plant and mine at Morenci except for those necessary for the orderly shutdown of operations as soon as possible."

Babbitt had suggested a 10-day cooling off period and an attempt to resume negotiations in a strike that began July 1 with cost-of-living benefits in a new three-year contract as the main issue.