Sensores electrónicos de bajo coste aplicados a la monitorización online del material atmosférico particulado producido por minería a cielo abierto

Zusammenfassung

In open-pit mining, there is a significant source of particulate matter (PM) in the atmosphere due to continuous earthmoving, mineral size reduction, treatment, and storage operations. This high PM concentration is associated with adverse health effects, raising public health concerns regarding fugitive emissions from mining activities. However, due to the large scale of these operations, conventional control of these emissions proves to be challenging and expensive, motivating the mining industry to seek more efficient and cost-effective technologies. This thesis introduces innovative tools for addressing air quality monitoring in mining environments and their surrounding areas. These tools aim to enable a detailed study of pollutant distribution, thus facilitating decision support in situations of high pollutant concentration and continuous air quality monitoring in these regions. The experimental work for this doctoral thesis was conducted entirely within the premises of the Cerro Colorado open-pit mine, located in Riotinto, Huelva, one of the largest and most significant open-pit metal mines in Europe. It also encompassed an analysis of the mine's contribution to the nearby communities. The study begins with an extensive PM10 sampling campaign carried out in three towns within the Riotinto district. The results showed that average PM10 concentrations exceeded annual and daily limits in the population closest to the mine during the spring and summer. Furthermore, a significant enrichment of potentially toxic elements (referred to as EPT or PTE in English) was observed. The most significant finding was the substantial contribution of the mine to the enrichment of these contaminants, especially in the nearby communities. This finding motivated the development of tools for PM monitoring inside the mine. A novel methodology is proposed for the space-time monitoring of PM concentrations in open-pit mines using low-cost mobile sensors (referred to as Low-cost Sensors, or LCS), costing less than 300 €. These sensors were placed at various locations, ranging from areas with zero activity to intensely active mining zones. Detailed calibration of the mobile LCS was conducted to meet European standards. The results revealed PM concentrations, maximum and minimum levels, seasonal variations, and the primary sources of PM within the mine. The integration of these data with meteorological information allowed for the identification of pathways for fugitive emissions toward nearby populations, providing significant insights into addressing this issue in the mining industry. The study demonstrated the applicability of LCS for high-resolution PM monitoring in mining, supporting environmental managers in cost-effective decision-making against fugitive emissions. Together, these advancements represent a significant step towards a more sustainable and environmentally friendly mining industry. While a substantial portion of the study was conducted using commercial LCS, this thesis also proposed a custom wireless sensor network (WSN) design employing LoRaWAN technology. This solution meets scalability, low power consumption, autonomy, and deployment simplicity requirements, with a compact and customized hardware design. The system combines WSN with IoT and cloud computing, allowing real-time data visualization and providing the mining industry with a tool to make decisions aimed at minimizing PM generation when specific threshold alerts are triggered.