Turning waste into wealth: Process optimization as a pathway to mercury-free artisanal gold mining in Suriname

Interventions in artisanal gold mining (AGM) to reduce environmental impacts, such as mercury pollution, must prioritize economic gold losses, a primary motivation for miners. We systematically sampled feeds and tailings from two AGM operations in Northeastern Suriname processing secondary ores (alluvial, colluvial and eluvial) in zigzag sluice boxes with unbacked vinyl carpets. Miners discharge concentrates for amalgamation after one to three weeks of operation. This delayed cleanup causes severe bed overloading and hydrodynamic scouring, physically ejecting previously trapped gold into tailings. Consequently, operational gold recovery for eluvial/colluvial ore was only 34% (feed: 0.29 ppm Au), while a dry alluvial operation recovered 84.2% (feed: 0.62 ppm Au). Grain size analyses of tailings revealed major losses in coarse fractions (+2 mm) driven by a combination of hydrodynamic carry-over and unliberated gold locked in quartz. To mitigate this, we recommend size classification followed by targeted comminution of the coarse fraction. Additionally, significant fine gold losses (