Johannesburg - Platinum group Lonmin [JSE:LON] has made no decisions yet regarding the closure of some of its shafts, the company said on Tuesday."If the mine does not become operational soon, we will have to make some decisions," spokesperson Sue Vey said.According to Tuesday's Business Report, Lonmin would have to resume production by Friday or shut down some of its operations.Vey said no decisions had been taken to close shafts so far.Last week, Lonmin told investors it was monitoring the situation in relation to its existing bank debt facilities."The balance of probabilities is that the impact on production... will result in covenants being breached at the next test date on September 30," it said."Consequently, constructive discussions are now taking place with Lonmin's banking group to address this potential situation."Lonmin was reviewing all options available to strengthen its financial structure, including access to capital.Workers at Lonmin's Marikana mine have been on strike for the last three weeks, demanding a salary of R12 500 a month.On August 16, police fired on a group of protesting workers at Lonmin's Marikana mine, killing 34 and wounding 78. Another 10 people had died earlier in the week, including two policemen and two security guards. *Follow Fin24 on Twitter, Facebook and Google+.