Assessment of a Mining-Waste Dump of Galena Mine in the East of Morocco for Possible Use in Civil Engineering

Mining dumps, particularly inactive or abandoned mines located near makeshift mining towns, have significant environmental and social impacts. The Touissit-Boubker lead mine, operated for years by the Touissit Mining Company (CMT) and abandoned without rehabilitation, is an example of this socio-economic and environmental collapse. Large quantities of harmful solid waste containing clayey aggregates rich in lead sulphide have been dumped in dykes on the edge of the village of Touissit. These mining wastes were rewashed to extract galena causing a depletion of lead sulphide. The objective of this study is to evaluate the possibility of using washed mining waste as sandy aggregate for the manufacture of masonry mortar. Cylindrical mortar tests, made with various proportions of sand and mine waste were characterized by X-ray diffraction, scanning electron microscopy and mechanical analysis by uni-axial compressive strength after curing for 3, 14, 28 and 60 days. The results obtained revealed that the mining waste consists of dolomite, quartz and clay. The dehydration rate of the mortar specimens is strongly affected by the amount of the waste added and the grain size. The mechanical strength of the mortar specimens mostly depends on the grain-size of the aggregates than on the amount of mine waste added. The microstructure of the mortar did not change when sand was replaced by mine waste of the same grain size.