A descriptive and quantitative approach regarding erosion and development of landforms on abandoned mine tailings: New insights and environmental implications from SE Spain

Abstract

The San Cristóbal-Perules mining site in Mazarrón in southeast Spain was subjected to about a hundred years of intense mining activity for lead, silver, and zinc. Metallurgical operations (smelting, calcination, gravity concentration) carried out during the late nineteenth centuryearly twentieth century induced significant land transformation, and the most conspicuous wastes of this period consists of a chaotic piling of 'old' tailing deposits. Later on, during the mid-twentieth century, 'modern' tailings resulting from froth flotation were accumulated filling small valleys; these latter valley-fill tailings rose sequentially according to the upstream construction method, progressively raising the level of the dam during the process.Once abandoned, both types of tailing deposits underwent severe erosion, resulting in amosaic of erosional and sedimentary landforms developed upon (e.g., gully formation) and within them (e.g., piping). We made an inventory and classification of these landforms. Our study shows the geomorphic work to reestablish a new steady state between the tailings deposits and the local erosive conditions. This scenario implies several hazards related to the extremely high heavy metal contents of these tailings and the geomorphic instability of the deposits. We also quantified the tailings tonnage and erosion that occurred at one of the tailings dams (El Roble). As shown by an oblique aerial photograph taken in 1968, this dam had a terraced topography, whereas in 2013 this morphology had evolved into a badland-type relief with deep parallel gullies. By recognizing and surveying specific, remnant points along the benches and outslopes of the older terraced topography, we were able to build up a first Abandoned mine tailing deposits are extremely common in the semiarid scenarios of the SW USA, Australia, Chile, and Peru. Given the similarities of these scenarios with SE Spain, the example from Mazarrón may provide useful new insights regarding the erosion and geomorphic evolution of such tailing deposits. These matters should be addressed in key environmental actions such as mine closure plans and land reclamation projects. A solution may come via restoration of these deposits through landform design involving the building up of stable mature landscapes, which in turn can withstand erosion much more easily.

Erosion characteristics of different reclaimed substrates on iron tailings slopes under simulated rainfall

“…Manning roughness coefficient (n m ) and Darcy-Weisbach (f D ) were calculated by Eqs. (1) and 2, respectively:…”

Enhanced Geomorphic Design for Reclamation of Rural Waste-Scapes

“…While the success of the re-designed waste-scape is dependent upon many diverse aspects, the foundation for success can largely be attributed to designing the appropriate landform upon which ecological, chemical, and hydrological, processes may occur. For many years, abandoned mines have been shown to be subject to excess erosion and slope failure, thereby hindering vegetation productivity, local water quality, and return of native fauna (Martin Duque et al 2015;Toy & Hadley 1987).…”

Geochemical Characterization of Magnetite and Geological Setting of the Iron Oxide ± Iron Silicate ± Iron Carbonate Rich Pb–Zn Sulfides from the La Unión and Mazarrón Stratabound Deposits (SE Spain)

“…By 1927 there were 31 mines operating at San Cristóbal–Perules, with a total production of about 30,000 Mt/year with grades of 55% Pb and 1.2 to 2.0 kg/t Ag. At present the area is pervaded by huge piles of tailings extremely rich in Pb (mean = 1.24%) and Zn (mean = 0.61%), thus constituting a potential economic resource (Oyarzun et al, ; Martín Duque et al, ).…”