Alluvial Gold Mining in Ghana: A Hidden Cost Beneath the Glitter
Across Ghana’s river valleys and floodplains, thousands of men and women spend their days panning, digging, and washing for gold.
Known locally as galamsey, this form of alluvial mining, which extracts gold from sediments along rivers and streams, has become both a lifeline and a growing environmental concern.
Rivers carry alluvial gold deposits that form when minerals eroded from ancient rocks eventually settle in new locations, such as riverbeds and floodplains. In Ghana, these deposits are found within the Kibi Greenstone Belt, part of the Birimian rock system, one of West Africa’s most gold-rich regions.
Over the past two decades, Ghana’s rural communities have increasingly turned to alluvial mining as a means of survival. Soaring gold prices have made the practice more profitable than farming, especially as cocoa yields and other agricultural incomes decline. The result has been a mass movement of rural youth from farmlands to riverbanks, where gold can offer quick cash and a sense of independence.
(Fig. 1) shows a sharp rise in both gold and cocoa prices from 2015 to 2024, which directly correlates with the surge in galamsey (illegal small-scale gold mining) activities in Ghana. As gold prices nearly doubled within the decade, rural miners, especially those from cocoa-growing regions, found gold mining far more profitable than farming.
Simultaneously, while cocoa prices also increased, the gains were offset by high input costs, erratic rainfall, pest infestations, and declining soil fertility, making cocoa farming less rewarding. This price-driven incentive has prompted a shift of labor, particularly among rural youth, from agriculture and informal occupations into small-scale gold extraction due to its low entry cost and immediate income potential.
Concurrently, declining cocoa yields, reduced farm productivity, and competition for arable land have intensified this transition, positioning alluvial mining as a short-term economic substitute for dwindling agricultural income. The extraction process, however, is highly labor-intensive, requiring the removal of overburden and the manual washing of auriferous gravels to recover gold.
But the cost of this gold rush is high. Much of Ghana’s alluvial mining happens outside the law, on unregulated lands, and with little regard for environmental protection. Rivers that once ran clear now flow brown with silt and waste. Wash water and tailings from the mining process are dumped directly into nearby streams, turning them turbid and lifeless. Scientists warn that this sediment pollution, rich in fine clay and metal oxides, makes water unsafe for drinking and destroys aquatic habitats.
As richer deposits near the surface are depleted, miners are forced to process lower-grade material. Because the gold in these sediments is extremely fine, sometimes smaller than 75 microns, miners often use mercury to bind the particles into a heavier amalgam. The method is simple but dangerous. When the mercury-gold mixture is heated to recover the gold, toxic mercury vapors are released into the air, endangering the miners themselves and contaminating surrounding communities.
Residual mercury that enters rivers doesn’t disappear; it lingers. Unlike radioactive substances, elemental mercury does not decay or break down over time; it is a stable element that persists indefinitely in the environment. Instead, it undergoes chemical transformations: in water and sediments, bacteria can convert it into methylmercury, a highly toxic compound that bioaccumulates in fish and other aquatic life.
Once released, mercury can cycle between air, water, and soil for decades or even centuries. In the atmosphere, it can remain airborne for up to a year before returning to the earth through rainfall or dust deposition (UNEP, 2019). The result is a long-lasting toxic legacy that can threaten ecosystems and human health for generations.
A Safer Alternative based on Surface Chemistry
Recent field innovations among small-scale miners have explored the use of soap or biodegradable surfactants as substitutes for mercury in fine gold recovery. The idea relies on surface chemistry rather than chemical amalgamation.
Water naturally has high surface tension (around 72.8 mN/m at room temperature), which allows small gold particles to remain suspended or even float when air bubbles attach to them. Soaps and detergents are surfactant compounds with both hydrophilic (water-attracting) heads and hydrophobic (water-repelling) tails. When added to the slurry, these molecules align at the air–water interface and disrupt hydrogen bonding between water molecules, thereby lowering surface tension.
This reduction in surface tension breaks the air films that trap fine gold particles, allowing water to thoroughly wet their surfaces. Once wetted, gold loses its buoyancy and settles more effectively under gravity. Unlike mercury, which chemically reacts with gold to form an amalgam (Au + 2Hg → AuHg₂), surfactants work through physical–chemical modification of the slurry’s fluid properties.
An added advantage is that soap-based reagents are biodegradable and photodegradable—they break down naturally when exposed to sunlight and air. Ultraviolet (UV) radiation from sunlight breaks the hydrocarbon chains in soap molecules, accelerating oxidation and decomposition into harmless compounds, such as carbon dioxide, water, and simple organic acids. This means that soap residues do not accumulate or persist in the environment, making them a safe and sustainable alternative to mercury in artisanal operations.
The economic dynamics behind this problem are complex. When global gold prices rise, mining activity surges, legal or not. Every spike in gold value attracts more people to the trade, and every influx of miners contributes to the pollution burden.
The challenge, then, is finding balance. While gold sustains many rural families, the unchecked spread of alluvial mining threatens to destroy the very environment on which these communities rely. Experts argue that the solution lies in revitalizing rural economies, investing in agriculture, agro-processing, and community forestry—so that traditional sources of income can compete with the quick gains of mining.
Sustainable small-scale mining is possible, but it will require more than enforcement. It demands education, safer mercury-free recovery technologies, and, most importantly, viable alternatives for those who see no other path to survival. Without that, Ghana’s rivers may continue to bear the actual cost of its gold.
By: Alfred Yeboah, Mining and Minerals Engineer, OceanaGold Mine – Kershaw, South Carolina
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