Peru mine workers prepare to strike on Monday

* Workers plan to strike next Monday, Tuesday

* Federation upset by veto of law lowering retirement age

* Some unions won't participate

By Patricia Velez

LIMA, Oct 16 (Reuters) - Peru's national federation of mine workers said on Friday it will hold walkouts across the country next week, although several important unions have said they will stay on the job.

Since late September, the federation has planned a nationwide strike that would be held on Monday and Tuesday in one of the world's top metals exporters.

The federation is upset that President Alan Garcia rejected a law, initially passed by Congress, to lower the age for retirement. Workers also want Congress to throw out a rule that limits the amount they can earn from profits that are distributed to them by companies.

"The position of the workers is to go on strike on Monday starting at 9 a.m. (1400 GMT) and leave the mines," Luis Castillo, the federation's director, told Reuters.

The last time miners across Peru downed tools was in mid-2008 and the strike helped push copper prices toward a record high.

Globally, Peru ranks No. 1 in silver output, No. 2 in zinc, No. 3 in copper and tin, No. 4 in lead and No. 6 in gold.

The walkout would be held as minerals prices have gained ground since crashing in late 2008, and mining companies are expected to see higher third-quarter profits after a tough first half of this year.

According to Castillo, the strike will be supported by unions at Volcan (VOL_pb.LM), one of Peru's top zinc and silver producers, and at the Yanacocha gold mine of Newmont Mining (NEM.N).

Unions at Freeport-McMoRan's (FCX.N) Cerro Verde mine, one of Peru's main copper pits, are also expected to strike.

Unions at Xstrata's (XTA.L) Tintaya mine and at mines of precious metals producer Buenaventura (BVN.LM) (BVN.N) have yet to make a final decision on the strike.

Workers at the key mines and smelter of Southern Copper (SPC.LM) PCU.N will stay at work, along with workers at BHP Billiton's (BHP.AX)(BLT.L) Antamina mine, union officials said. (Editing by Terry Wade and Lisa Shumaker)