extern int MagicNumber = 12345;

extern int SecondsToClose = 180;

int start()
{
  CheckForClose();
}
void CheckForClose()
{
   int ticket, OrderTy;
   
   for(int i=OrdersTotal()-1;i>=0;i--)
   {
      OrderSelect(i,SELECT_BY_POS,MODE_TRADES);
      if(OrderSymbol()!=Symbol()) continue;
      if(OrderMagicNumber()!=MagicNumber) continue;
            
      if (TimeCurrent() - OrderOpenTime() >= SecondsToClose)
      {
         if (OrderType() == OP_BUY) OrderClose(OrderTicket(), OrderLots(), Bid, 3, Red);
         if (OrderType() == OP_SELL) OrderClose(OrderTicket(), OrderLots(), Ask, 3, Red);
      }
   }
   return;
}