Water footprint in gold extraction: A case-study in Suárez, Cauca, Colombia

Christian E Alvarez-Pugliese,Fiderman Machuca-Martínez,Mario Pérez-Rincón

doi:10.1016/j.heliyon.2021.e07949

Abstract

This research deepens the analysis of the mineral water footprint, especially that of gold, in regions that are understudied and where mining has been an intensified extractive activity since the colonial era, as is the case in the northern part of department of Cauca in Colombia. Thus, the purpose was to estimate the water footprint indicators in gold mining in Suárez (Cauca, Colombia), to quantify the impacts generated by the non-returned water in the production process and the levels of pollutants in the wastewater, aimed to strength public policies, control strategies and mitigation that generates reductions in the impacts from mining activities on the environment. The blue water footprint was estimated in 79.91 m3 per kg of gold extracted and the gray water footprint was found to be in the range of 272,125.39 to 404,825.11 m3 per kg of gold extracted. The water footprint values obtained were compared with other mines with similar operations. These results generate a baseline for decision making, providing elements for environmental strategic planning, regulations and showing the great environmental pressure that gold activity exerts on water resources and the territories.

Highlights

Seventy-one percent of the earth's surface is covered by water; less than 1% of the planet's potable water is suitable for human consumption [1]
It is important to highlight the percentage of gold production in the municipality according to the type of deposit estimated for the baseline scenario, which was 97.7% for primary ore mining and 2.3% for alluvial mining, values that agree with previous reports [22, 24, 27] that mention underground gold mining is the dominant type of production in the Suarez
A 2016 study [4] used satellite images and other remote sensing tools to quantify the number of hectares affected by mining in Colombia, determining that the department of Cauca has the least impact among the seven gold producing departments, according to the authors this may be due to a lack of accountability for primary ore mining in the remote sensing method used

Summary

Introduction

Seventy-one percent of the earth's surface is covered by water; less than 1% of the planet's potable water is suitable for human consumption [1]. The distribution of water is not homogeneous across the Colombian territory, and the outlook is troubling due to excessive human pressure from population growth and, above all, by the recent specialization of Colombia's economy towards primary sector production, which uses water intensively [3]. In Colombia, the largest water consumers are the agricultural, energy and livestock sectors, which constitute 76.6% of the domestic total water use. The mining sector demands 1.8% of total domestic water consumption. Considering that 82% of gold production is alluvial-type exploitation (direct exploitation of the riverbed), of which 95% corresponds to illegal mining [4], and that this type of activity uses pollutant chemicals in its extraction process, the risks of contamination and the generation of wastewater contaminated with mercury and cyanide are high and can have drastic impacts on human populations and ecosystems

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Results

Conclusion