Browsing by Author "Bituh, Tomislav"

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Radioactivity distribution in soil, rock and tailings at the Geita Gold Mine in Tanzania
(Elsevier, 2025-04-30) Mwimanzi, Jerome; Haneklaus, Nils; Bituh, Tomislav; Brink Hendrik; Katarzyna Kiegiel; Lolila, Farida; Marwa, Janeth; Rwiza, Mwemezi; Mtei, Kelvin
This study evaluated the activity concentrations of natural radionuclides in soil, waste rocks and tailings from the Geita gold mining site in Tanzania using high-resolution gamma spectroscopy. A total of 41 samples: 31 soil, 5 waste rock, and 5 tailing samples were collected around the mine to assess their radiological hazards. The average activity concentrations in soil were 54, 45 and 279 Bq kg-1 for 226Ra, 232Th and 40K. In contrast, tailings exhibited higher activity concentrations of 70, 36 Bq kg-1 for 226Ra and 232Th, and significantly elevated levels of 877 Bq kg-1 for 40K, while waste rocks showed intermediate values, with 66, 73 and 660 Bq kg-1 for 226Ra, 232Th and 40K respectively. Radiological hazard indices were calculated to quantify potential risks. In soil, the radium equivalent activity (Raeq) averaged 139 Bq kg-1, the annual effective dose equivalent (AEDE) was 78 μSv y-1, the annual gonadal dose equivalent (AGDE) reached 430 μSv y-1, and the excess lifetime cancer risk (ELCR) was 0.27 × 10-1. Tailings showed a Raeq of 189 Bq kg-1, AEDE of 111 μSv y-1, AGDE of 678 μSv y-1, and ELCR of 0.39 × 10- 1, while waste rocks exhibited a Raeq of 200 Bq kg-1, AEDE of 108 μSv y-1, AGDE of 642 μSv y-1, and ELCR of 0.37 × 10-3. Notably, the ELCR values for tailings and waste rocks exceeded the global average of 0.29 × 10-3, rendering them unsuitable for use as building materials. The absorbed dose rates were 69 nGy h-1 for soil, 91 nGy h-1 for tailings, and 88 nGy h-1 for waste rocks. One-way ANOVA revealed significant differences (p < 0.05) among the matrices. These findings underscore the need for targeted waste management and remediation strategies to mitigate radiological health risks in the investigated mining area as well as other areas with similar characteristics
Rare earth elements and uranium in Minjingu phosphate fertilizer products: Plant food for thought
(ELSEVIER, 2024-08-01) Haneklaus, Nils; Mwalongo, Dennis; Lisuma, Jacob; Amasi, Aloyce; Mwimanzi, Jerome; Bituh, Tomislav; Ćirić, Jelena; Nowak, Jakub; Ryszko, Urszula; Rusek, Piotr; Maged, Ali; Bilal, Essaid; Bellefqih, Hajar; Qamouche, Khaoula; Brahim, Jamal; Beniazza, Redouane; Mazouz, Hamid; Merwe, Elizabet; Truter, Wayne; Kyomuhimbo, Hilda; Brink, Hendrik; Steiner, Gerald; Bertau, Martin; Soni, Raghav; Patwardhan, Ashwin; Ghosh, Pushpito; Kivevele, Thomas; Mtei, Kelvin; Wacławek, Stanisław
Minjingu phosphate ore is Tanzania's sole domestic supply of phosphorus (P). The ore contains medium to high concentrations of naturally occurring P2O5 (20–35 %) and relevant concentrations of uranium and rare earth elements (REEs) are also suspected to be present. Currently, neither uranium nor REEs are recovered. They either end up in mine tailings or are spread across agricultural soils with fertilizer products. This work provides a first systematic review of the uranium and REE concentrations that can be expected in the different layers of Minjingu phosphate ore, the way the ore is presently processed, as well as a discussion on alternative processing pathways with uranium/REE recovery. The study analyzed ten distinct Minjingu phosphate ore layers, four mine tailings, and five intermediate and final mineral fertilizer products from the Minjingu mine and processing plant located in northern Tanzania. The results confirm that the uranium concentrations and to a lesser degree, the REE concentrations are indeed elevated if compared to concentrations in other phosphate ores. The study does not identify a significant risk resulting from this. The development of techno-economic solutions for more comprehensive utilization of Minjingu ore is, however, strongly encouraged and suggestions on such processes are provided.