JOHANNESBURG (Reuters) - World no. 3 platinum producer Lonmin said on Friday it had given its striking South African miners until May 8 to accept its latest wage offer and that they needed to be back to work by May 14. Spokeswoman Sue Vey said the company still could not say how much of its workforce had indicated they wanted to return to the job. Impala Platinum said earlier that two-thirds of its striking workers had said by phone and text message that they wanted to end a 14-week stoppage. [ID:nL6N0NO0Z6]