I don't know the details about other mining companies, but I know a few details about the Ivanhoe mines corporation.
Some mining companies in Burma in the past didn't have that kind of bad reputation, as far as I can see. They were just there to explore the possibility of investing or exploring to see if any mining resources were there. Some companies left the country after they saw the investment would not be profitable for them.
Ivanhoe is the only company that had a bit of a headache. Ivanhoe is not free from some kind of irregularities in Burma too. Ivanhoe also faced lots of difficulties in terms of the way the Burmese government handled things. Ivanhoe faced many difficulties as well.