The company has a few options related to haulage, below are the...

The company has a few options related to haulage, below are the criteria for assessment
Its hard to tell without being there but these are the main points
1. Road maintenance over the long haul
2. Pit inward/outward access/conditions
Cheap option upfront/more costly with road maintenance:
If the areas are not difficult to maintain (soil type & density etc) you can use road trains, but as the roads get gluggy prior to and after the wet season you will have difficulties, and the road will require a decent level of maintenance all year round.
Expensive option upfront/cheaper with road maintenance.
Haulmax Trucks www.haulmax.com (all the specs available on this site)
In the current economic climate though, there is a glut of plant sitting around in a dealers yard scond hand that they are screaming to get off there books, due to the down turn in the mining in Oz. It wouldn't be hard to find a small fleet of these with low hours on the cheap and ppound for pound over this distance would be hard to beat for speed and hauling capacity.
First hand experience with Haulmax Trucks in a tropical environment and they rocked up and down hills in PNG, not on what I would think would be relatively flat terrain on the current haul road. No need to upgrade the from a 35T excavator to load due to longer than normal cycle times.