Physico-chemical Characteristics of Wastewater from a Ball Mill Facility
in Small-Scale Gold Mining Area
of Paracale, Camarines Norte, Philippines

Jessie O. Samaniego1,2,* and Maria Antonia N. Tanchuling2

1Department of Science and Technology - Philippine Nuclear Research Institute,
Commonwealth Ave., Quezon City, Philippines

2Environmental Engineering Graduate Program, College of Engineering,
University of the Philippines - Diliman, Quezon City, Philippines

*Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.



Small-scale gold miners in Paracale, Camarines Norte use amalgamation process to recover gold from mined ores. In the process, they dispose untreated wastewater to water bodies. In this study, wastewater from an active SSGM ball mill facility in the area was analyzed for physico-chemical parameters and heavy metal concentrations. A total of 40 samples were gathered from the ball mill facility while in full operation and were analyzed for heavy metals (As, Ba, Cd, Hg, Pb). Results showed that all metals (except for Ba) exceed the effluent regulatory limits including Hg (0.1768 mg/L) and Pb (9.3821 mg/L), which are 44 and 94 times higher than the limit, respectively. Presence of Hg concentration in the wastewater confirms the miners’ illegal use of Hg in amalgamation process. Based on the mercury balance in amalgamation, around 16.8% of total Hg input goes to the sediment and some 0.21% mixed with wastewater and the bulk 82.99% is in the form of amalgam that becomes Hg vapor after burning. Physico-chemical parameters – temperature, pH, and true color – are within their respective effluent regulatory limits for Class C waters, while TSS (3,596.9 mg/L) is 36 times higher than the 100 mg/L limit. Other parameters, though not regulated, such as ORP (343.9 mV), turbidity (> 800 NTU), and apparent color (9,880 PCU) were analyzed with high concentrations. From this study, wastewater treatment is recommended before disposing of to the receiving waters to reduce the concentration of heavy metals and TSS. Also, the full and strict implementation of the people’s small-scale mining law must be maintained to protect human health as well as the environment from the adverse effect of the use of Hg in SSGM processes.



Small-scale gold mining (SSGM) plays an important role in poverty alleviation in the rural communities, especially in the developing countries including the Philippines. It is a source of livelihood of at least 10-20 million people worldwide (Telmer & Veiga 2008), while the International Labor Organization (ILO) extrapolated that 80-100 million people worldwide are directly and indirectly dependent on this activity for their livelihood (Hinton et al. 2003; Hentschel et al. 2003). As the price of gold continues to rise, the SSGM activities around the world also continue to grow. In effect, the demand for mercury (Hg), which is being used in amalgamation process in many SSGM areas, is also increasing and currently it represents 1/3 of worldwide Hg consumptions (Telmer & Veiga 2008). . . . . read more



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