Sediment texture and Rare Earth Element (REE) content in the marine placer tin mining area of Eastern Bangka Island

Abstract This study was conducted in the marine area of Bangka, encompassing the eastern coastal waters from Pangkalpinang City (Pasir Padi Beach) to Central Bangka Regency (Tanjung Gunung Beach. A total of 15 solid samples were taken, consisting of 2 solid samples representing the mouth of the river leading to the sea and 13 solid samples distributed along the sea water, each weighing about 2kg. The sample was prepared in a dry condition with a weight of 500 g per sample using a sieve shaker with fraction sizes of 120; 140; 180; 200; 250 and >250 mesh. The results of substrate content testing sediment for each sample showed texture classes categorized as Sandy Loam (Silt 0.56%, Sand 82%, and Caly 17.37%). Laboratory elemental analysis using a portable XRF instrument was performed on mesh-sized samples from fifteen specimens, yielding thirty-one periodic element readings. These substrates were dominated by metals containing stable radioactive isotopes, notably Yttrium (Y), while Thorium (Th) and Uranium (U)—radioactive elements with long-lived isotopes—were also present. The average concentrations of Yttrium (a heavy rare earth element) were 864.8 ppm, Thorium (Th) was 39.71 ppm, and Uranium (U) was 15.4 ppm.