Lima, Oct 20 -- Many employees at key mines in Peru reported to work on today as a 48-hour mining strike entered its second day with lukewarm support, while workers hoped Congress would vote to improve their benefits. Miners in Peru, a leading global metals exporter, have demanded the government pass laws that would lower the age for retirement and lift caps on profit-sharing. Congress could vote on the rules Wednesday (Oct 21) or Thursday, depending if they are put on its agenda. Early retirement for miners might require private pension funds to pay out millions of dollars in extra benefits. Union leaders said the walkout hit mines of Buenaventura, Barrick and Volcan, while those of Southern Copper, Freeport, BHP Billiton, Xstrata and Newmont were spared. Peru's labour ministry has declared the strike illegal, a move aimed at prodding miners to return to work. Buenaventura has said its Orcopampa and Uchucchacua mines were stopped by the strike. Union officials said workers at Barrick'