Leaching and Geochemical Modelling of an Electric Arc Furnace (EAF) and Ladle Slag Heap

Old metallurgical dumps across Europe represent a loss of valuable land and a potential threat to the environment, especially to groundwater (GW). The Javornik electric arc furnace (EAF) and ladle slag heap, situated in Slovenia, was investigated in this study. The environmental impact of the slag heap was evaluated by combining leaching characterization tests of landfill samples and geochemical modelling. It was shown that throughout the landfill the same minerals and sorptive phases control the leaching of elements of potential concern, despite variations in chemical composition. Although carbonation of the disposed steel slags occurred (molar ratio CO3/(Ca+Mg) = 0.53) relative to fresh slag, it had a limited effect on the leaching behaviour of elements of potential concern. The leaching from the slag heaps had also a limited effect on the quality of the GW. A site-specific case, however, was that leachates from the slag heap were strongly diluted, since a rapid flow of GW fed from the nearby Sava River was observed in the landfill area. The sampling and testing approach applied provides a basis for assessing the long-term impact of release and is a good starting point for evaluating future management options, including beneficial uses for this type of slag.

MYTHS, RITUALS AND RESTRICTIONS OF THE AFRICAN IRON INDUSTRY IN THE 18th CENTURY: THE CASE OF TAAVISA IN NSO’ GRASSFIELDS OF CAMEROON

The peculiarity of the African iron industry is its cultural dimension; where in, symbolism was evident in virtually all the stages of the production chain. With the use of archival, secondary and oral sources, this paper investigated the Taavisa slag heap which revealed that smelting residue was cleared to create space for a royal cemetery and a hut constructed over the grave of Fon (king) Sanggu of Nso’ around 1750. Sanggu was probably the seventeenth Sovereign of the Nso’ Dynasty at Kovifem, who died while in refuge on the peripheries of his kingdom, subjected to Chamba and later Fulani raids. Taavisa was a retreat spot in several situations and developed into a rest palace for reigning Fons of Nso’. Given its strategic location, smelting, pre-forging and sanctity which emanated from iron works, this old iron working site became a place of honour and thus mutated into a shrine. Thus, multidimensional values attached to Taavisa account for Nso’ seizure of the area and subsequent expansion towards its southern boarder Fondoms (Kingdoms). A new element therefore adds to symbolisms attached to the African iron industry that is: a smelting site turned into a royal cemetery.

Rapid characterisation of the extremely large landslide threatening the Rules Reservoir (Southern Spain)

When an active landslide is first identified in an artificial reservoir, a comprehensive study has to be quickly conducted to analyse the possible hazard that it may represent to such a critical infrastructure. This paper presents the case of the El Arrecife Landslide, located in a slope of the Rules Reservoir (Southern Spain), as an example of geological and motion data integration for elaborating a preliminary hazard assessment. For this purpose, a field survey was carried out to define the kinematics of the landslide: translational in favour of a specific foliation set, and rotational at the foot of the landslide. A possible failure surface has been proposed, as well as an estimation of the volume of the landslide: 14.7 million m3. At the same time, remote sensing and geophysical techniques were applied to obtain historical displacement rates. A mean subsidence rate of up to 2 cm/yr was obtained by means of Synthetic Aperture Radar Interferometry (InSAR) and Ground Penetrating Radar (GPR) data, during the last 5 and 22 years, respectively. The Structure-from-Motion (SfM) technique provided a higher rate, up to 26 cm/yr during the last 14 years, due to compaction of a slag heap located within the foot of the landslide. All of this collected information will be valuable to optimise the planning of future monitoring surveys (i.e. Differential Global Positioning Systems, inclinometers, ground drilling and InSAR) that should be applied in order to prevent further damage on the reservoir and related infrastructures.

The second Caloneurodea from the Moscovian of Avion, France (Insecta, Archaeorthoptera)

The Late Palaeozoic insect order Caloneurodea Handlirsch, 1907 is a rather small clade in the superorder Archaeorthoptera Béthoux & Nel, 2002 (Béthoux et al., 2003), several representatives have been recently described from Portugal, France, China, and Russia (see Dvořák et al., 2021 and references herein). The body structures of these insects are poorly known and the majority of genera and species are based on isolated wings. Also the majority of genera and species are Permian and latest Carboniferous. With two genera and species recorded from the Moscovian of the Pas-de-Calais Basin, this area is of great interest to estimate the diversity of this order during the early Pennsylvanian (Pruvost, 1919; Prokop et al., 2014). Here we describe the second genus and species from the Avion locality, which has already given Aviogramma gracilis Prokop et al., 2014. This discovery further confirms the very important richness and diversity of the fossil entomofauna of the slag heap of Avion (Nel et al., 2013).

Aberfan: In Memoriam

It was an ordinary day in Aberfan, Wales, and it ended in a disaster. On October 21, 1966, a 34-meter-high slag heap broke loose, slid down Mount Merthyr into the mining village and buried houses and an elementary school there. The result: 144 people died, 116 of them children. October 21, 1966 was a gloomy day in Aberfan, South Wales. It had been raining incessantly for days. But the children in the mining village were happy: they were looking forward to the autumn vacations. This was their last day at school. But then disaster struck.

A new paleopteran genus and species from the late Carboniferous of Avion France, (Insecta: Palaeodictyopterida: ?Diaphanopterodea)

The Carboniferous outcrop near Avion, in the Department of Pas-de-Calais, northern France, is very rich in fossil insect wings, which are preserved alongside thousands of plant fragments. Its entomofauna is very diverse, including representatives of the Palaeodictyoptera, Odonatoptera, Archaeorthoptera, Caloneurodea, Paoliida, Dictyoptera, Plecoptera, and the oldest representatives of the clades Acercaria and Holometabola (Nel et al., 2013, Prokop et al., 2013, 2014; Coty et al., 2014; Schubnel et al., 2019a, b). The fossil insects were found in ‘Terril N 7’, a slag heap located in the Avion area comprising Moscovian-aged sediments derived from Liévin coal mines 3 and 4, specifically the Bolsovian or Westphalian C (311–308 Ma) ‘faisceaux de Ernestine’, and the Asturian or Westphalian D (308–306 Ma) ‘veines Arago, Dusouich, Marthe’ informal beds (Bruno Vallois, 2013, pers. comm.).

Control of Contaminant Transport Caused by Open-Air Heavy Metal Slag in Zhehai, Southwest China

Slag heaps are formed by mining waste materials, and the improper treatment of leachate from such heaps can threaten nearby aquifers. The Zhehai slag heap in Yunnan Province, China, contains 2.7 million tons of zinc and cadmium slag, and is considered a heavy metal source threatening the local groundwater safety, however, the severity of contamination remains unknown. In this study, numerical modeling was used to predict the groundwater flow and contaminant transport in this area based on field data. The results show that the atmospheric precipitation infiltration recharge at the top of the heap is 81.8 m3/d, accounting for 93.76% of total infiltration. The south and east sides of the area are the main outflow channels for contaminants, accounting for 93.25% of the total discharge around the heap. To reduce aquifer contamination, an in situ system involving a “controlling the source, ‘breaking’ the path, and intercepting the flow” (CSBPIF) strategy is established. The results indicate that the system performs well because it not only decreases the flow velocity but also reduces the concentrations of contaminants adsorbed by clay media. Moreover, the equivalent bottom liner thicknesses of the clay layers were calculated to improve the applicability of the CSBPIF system. Compared with ex situ disposal, this scheme provides an economic and effective solution and can be used to prevent and control groundwater pollution in China.