Geological Evaluation and Environmental Implications of Gravel Resources in the Sylhet Quarry Belt, Northeastern Bangladesh

Abstract

The Sylhet district of northeastern Bangladesh hosts the nation’s most significant and economically vital stone and gravel deposits, forming a crucial link in the country’s construction materials supply chain. This study systematically assesses the spatial distribution, reserve potential, and environmental implications of these resources within Companiganj, Gowainghat, Jaintiapur, and Kanaighat upazilas. An integrated geological and geophysical investigation was conducted using land surveying, chopping boring, auger boring, test-pit excavation, resistivity profiling, and granulometric analysis. A total of 958 boreholes and test pits were examined. Results indicate an estimated 536.16 million cubic feet (MCF) of recoverable stone within the 5 m legal extraction depth and approximately 4,918.57 MCF of total reserves to a depth of 30 m. Jaflong, Bholaganj, and Uttma quarries represent the richest deposits. Petrographic analyses reveal increasing textural maturity and rounding toward distal depositional sites, consistent with fluvial reworking processes. However, decades of unregulated extraction have caused severe geomorphic and ecological degradation. The study emphasizes the necessity of a scientifically guided, environmentally sustainable resource management framework, incorporating regulated extraction, post-mining rehabilitation, and community-based monitoring to balance economic development with environmental conservation in the Sylhet Basin.