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Heavy mineral resource potential of Tista river sands, Northern Bangladesh

2018; Taylor & Francis; Volume: 127; Issue: 3 Linguagem: Inglês

10.1080/25726838.2018.1488357

2572-6846

Pradip Kumar Biswas, Soshe Ahmed, Mark I. Pownceby, Nawshad Haque, Md. Sha Alam, Mohammad Nazim Zaman, Md. Aminur Rahman,

Geological and Geochemical Analysis

Surface and borehole sampling along a ∼80 km section of the lower Tista river, northwestern Bangladesh, indicated that the river sands offer significant potential as a heavy mineral (HM) resource. Characterisation of sediments from the surface to 15 m depth showed that the sand-sized component was dominated by quartz, feldspar, mica, lithic fragments, amphibole and pyroxene group minerals. The most common particle size was between +125–500 μm with 84 wt-% of all material reporting to this size range. Laterally spaced sampling indicated slight grain size coarsening upstream. Heavy liquid separation studies revealed that HMs such as amphiboles, micas, garnets, aluminosilicate (Al2SiO5) phases, ilmenite and zircon made up ∼10.99% (on average). The percentage of valuable HMs (ilmenite, rutile, zircon, monazite, garnet) was 2.47% (average). Detailed borehole sampling and resource mapping of a large, mid-channel sand bar showed that placer-style HM accumulations occur upstream and along the margins of the bar.