Mail handlers overwhelmingly ratified a new contract with the U.S. Postal Service by 9 to 1, the union announced yesterday.

The contract, which will remain in effect until Nov. 20, 1990, covers 50,000 Postal Service employes who postmark mail and load and unload it within Postal Service facilities.

The employes who overwhelmingly ratified the deal are represented by the Mail Handlers Division of the Laborers' International Union of North America (LIUNA).

The new agreement provides immediate 2 percent wage increases. It also calls for raises of $250 in July 1988 and January 1989; $300 in July 1989 and January 1990, and $200 in July 1990.

The raises are retroactive to July.

The pact also includes cost-of-living adjustments, job security language and overtime provisions.

Drew Von Bergen, a spokesman for the mail handlers, said 17,011 members approved the contract, and 1,925 voted against it. He said almost 49 percent of the union's members voted on the agreement.

The pact was announced July 14 and preceded a last-minute settlement July 21 between the Postal Service and its two biggest unions: the National Association of Letter Carriers and American Postal Workers Union (APWU).

Members of the APWU also voted "overwhelmingly" to approve their contract with the Postal Service, spokesman Danny Frank said. The final count showed 105,786 union members voted in favor of the plan, and 26,851 voted against it, Frank said. The APWU represents 350,000 post office employes.