Redesign and fabrication of a sluice box for improved portability and gold recovery

Abstract

The project addressed the critical inefficiencies in existing sluice box designs used by artisanal gold miners in the Tiira gold mines, Uganda. These inefficiencies included difficulties in feed and water delivery, suboptimal inclination angles and the use of materials that contributed to high mercury contamination, posing significant threats to both environmental health and miner wellbeing. To overcome these, the project aimed to redesign and fabricate a portable and efficient sluice

box for

artisanal gold miners in Tiira, Uganda, addressing inefficiencies in existing designs such as poor feed delivery, suboptimal inclination angles, and high mercury contamination. The research focused on four specific objectives which included determination of optimal sluicing parameters for improved recovery efficiency, development of a portable and efficient sluice box design, fabricating and testing the new design to evaluate its performance then lastly performing financial analysis to which determined the economic viability of the project. Through field surveys and laboratory analysis of ore samples, key sluicing parameters including slope angle, water flow rate, and feed rate were optimized using Response Surface Methodology (RSM) and Central Composite Design (CCD). The redesigned sluice box achieved a 20.1% increase in gold recovery (from 67.75% to 87.8%) by implementing an optimal slope angle of 13.5°, a sluice length of 1.3 m, and a width of 0.6 m. Sensitivity analysis revealed that slope angle contributed 40.65% to recovery efficiency, followed by velocity (22.76%) and flow rate (20.33%). Constructed from mild steel for durability and portability, the final prototype weighed 12.88 kg and featured foldable components for ease of transport. Financial analysis confirmed viability, with a 2.8-year payback period and a profitability index of 2.944. The project demonstrates that optimized sluice box designs can significantly enhance gold recovery while reducing environmental and health risks associated with mercury use in artisanal mining. Future work should focus on material/riffle optimization for better performance and cost. Essential training for miners on optimal techniques and sustainable methods is crucial. Subsequent efforts must address scaling up the design for mass production and wider adoption.