I would not be concerned with PT and their future, outside of the family loosing interest in the business and selling bits off. They do well for what they are, which is a niche market company. I researched them a bit and with the three companies combined they pull in 70mil plus a year (And I think much more).
Coal is not going anywhere in our lifetime, I am sure given how much is mined in China. PT might be selling like hotcakes over there and that is not disclosed.
I feel that the company sells what they feel comfortable in selling, that they don't see the need to take a risk and expand. Given the fact they weathered the downturn with no reduced staff speaks volumes for the health of the company. Do I agree with their motivation, not really but hey, its not my company.