Quantification of Pollutants in Mining Ponds Using a Combination of LiDAR and Geochemical Methods—Mining District of Hiendelaencina, Guadalajara (Spain)

Abstract

More than twenty years after the last mining operations were completed in the Hiendelaencina Mining District, it is necessary to carry out a geochemical characterisation of the tailings stored in two contiguous mine ponds. Both have significant amounts of quartz, siderite, barite and muscovite and show significant contents of As, Ba, Pb, Sb and Zn. The tailings show alkaline pH and low electrical conductivity values, which support the visual observation that rules out acid drainage into the environment. The comparison of the National Topographic Map of 1954 with LiDAR data from 2014 has allowed estimating the volume of abandoned waste. Based on the volume of slurry and its average density, the total tonnage of pollutants has been estimated at 279 ± 9 t stored in Pond North and 466 ± 11 t stored in Pond South. Although these are significant quantities that pose a risk to the environment and nearby populations, they are lower than those present in other Spanish districts, such as the Iberian Pyrite Belt or Cartagena-La Unión. The combined use of LiDAR data, aerial imagery and geochemical methods has proven to be very useful for the estimation of the volume of pollutants stored in mine ponds.

Analysis of Storage Capacity Change and Dam Failure Risk for Tailings Ponds Using WebGIS-Based UAV 3D Image

“…The conventional methods employed for safety monitoring of tailings ponds mostly rely on a combination of manual operation of total station measurement and sensor monitoring, which could be not only time-consuming, laborious, and costly, but also subject to a range of factors such as weather and site conditions [18,19]. In an effort to address these challenges, researchers such as Martinez-Segura et al [20], Martin-Velazquez et al [21], and Martin-Crespo et al [22] have turned to newly merged 3D LiDAR technology to estimate mining and tailings pond volumes, but the high cost may prohibit this technology from its widespread application in tailings ponds [23]. On the other hand, unmanned aerial vehicle oblique photography (UAVOP) has become prevalent in various fields [24][25][26] because of its advantages of timeliness, flexibility, and relatively low overall cost [27,28], enabling relatively accurate representation of model texture features and the acquisition of spatial 3D data [29].…”