The operation in Columbia is Drummond Ltd.
It began its 192 Km (119 mile) haul in Columbia between a open pit coal mine to a seaport in 1995 with four diesels. The other year the roster included something like 40 units -- 24 U18C built 1995 through 2002), 7 U20C (second-hand built 1964), 6 C21EMP (built 2005), and one 90-ton center cab switcher. It was expected to be ordering more C21EMP's in the near future. The operation has more than 1500 cars rotary dump coal cars.
Drummond has a website and a page about its Columbian operation. You will find it at this link:
Drummond - Columbia The company has an interesting video that shows its operations in Columbia and promotes its social programs there.
Brian Norden