Les carrières de marbre du massif de Filfila (Est de Skikda ; Algérie nord-orientale)

Abstract

The study area belongs to the internal domain of the Alpine chain in the north-eastern of Algeria, in which Filfila massif, including marble deposit, is a segment of the base Kabylie. The marble deposit of Filfila massif appeared like a tectonic window due to the erosion of the base of Petite Kabylie, it is the result of a contact metamorphic of average degree, which accrued between the granitic intrusions of the Langhian Age and the carbonate formations of the Lias, which occupied the lowest stratigraphic position in the parautochthon complex. Petrographic study of deferens facies of the marble at this deposit has shown the carbonate nature of the marble; the opened gray colour is the most dominant one (72.75%). The mineralogical study of the marbles revealed its richness by the calcite (94 to 99 %), this latter has a massive texture and essentially microcrystalline structure, and apparently it was recrystallized from a homogenous limestone, affected in some location by dolometazation. The treatment of the marble chemical data of the samplings indicates of the homogeneity of the marble, and its stability of CaCO3 in depth with content varies from 94 to 99%, it is also characterized by the presence of small amounts of oxides of some elements. The analysis of the fracturing as a key criterion in assessing the quality of the marble has shown a vertical development, in general way; the major orientation of the cracks is to the NE-SW, (N40°-60 °E). The applied method of exploitation in the Filfila quarry relies on the use both of the cutter machine and diamond wire together, but the existence of fracturing in the marble of this deposit requires a specific technique. While the high intensity of fracturing in the marble of El-Chatt quarry justifies its operations by explosives, knowing that more than 70 % of the marble reserve in this deposit are not yet extracted. However in order to improve the rate of recuperation of the marble that we extract from the quarry of Filfila ( decrease scraps to the minimum) , we should guide the operating front in a direction parallel to the major direction of cracking in the marbles, in order to extract blocks with a minimum cracks (1st choice). We suggest also spending the upper part of El-Chatt quarry for producing the powders, because it consists essentially of the white marble.