A techno-economic evaluation of the mining and processing of heavy mineral sands from the Brahmaputra river basin, Bangladesh

A preliminary laboratory separation of heavy mineral-containing sand samples from the Brahmaputra River basin, northern Bangladesh successfully produced ilmenite-, magnetite-, garnet-, and zircon-rich concentrates. Based on a previous mineral characterization study, a first-pass techno-economic model for mining and processing of the mineral sands was developed. A 1400 t/h mine dredge and associated dry mineral separation plant was considered for the model. It was calculated that a mine dredge path for the first 25 years of the operation is likely to extract 200 Mt of ore at a grade of 1.9% heavy minerals (HMs) over a 40, 000 ha mining area. The estimated capital cost (including contingency) is approximately US$230 million and the operating costs are projected to average approximately US$20 million annually. The internal rate of return based on the first 25 years of operation (with no terminal value) is 15% and the projected payback period is approximately 9 years after the operation commences.