Valtreixal Resources Spain S.L., an indirect wholly-owned subsidiary of the Company, owns a 100% interest in the Valtreixal tin and tungsten mine project located in Western Spain (the “Valtreixal Mine”). The principal business of Valtreixal Resources is the exploration of the Valtreixal Mine.
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Summary:
The local Valtreixal stratigraphy in the Valtreixal area is dominated by 3 main formations, all of which broadly strike SW-NE, and dip at approximately 80o to the south- east.
a) Schists - Capas de los Montes. Very stratified and transformed by regional metamorphism, with intercalated quartzites, and marked at the base by conglomerates. Thickness approximately 1000m.
b) Quartzites - Peña Goda/Culebra. Alternating with a variety of types and colours of intercalated schists. Thickness approximately 50- 70m.
c) Slates – Pizarras de Luarca. Pelitic series of siliceous slates, phyllites and schists. This formation hosts most of the mineralisation at Valtreixal. High frequency of segregated quartz veins and schist bands sometimes rich in sulphur. Overall thickness approximately 300-600m.
Much of the mineralisation, especially scheelite, is situated away from the quartz veins and appears to be stratabound. Tin, in the form of cassiterite, occurs in and around the quartz veins. The Valtreixal linear mineralised zones appear, in a general sense, to be confined to specific stratigraphic intervals and there appears to be a degree of separation into tin and tungsten zones. Because of the stratabound nature of the mineralised zones within a shale basin some may consider a sedimentary, syngenitic origin for the tungsten mineralisation to be plausible.
The Valtreixal tungsten (scheelite) and tin (cassiterite) mineralisation exhibits two principal modes of occurrence within southeast dipping, weakly schistose Ordovician shale in the Hercynian (Variscan) tectonic belt. Irregular quartz veins cut the moderately steeply southeast dipping shale and may have associated tin and tungsten mineralization especially where the veins are brecciated and the adjacent wall rock has been altered to sericite schist.
In places it was observed that minor amounts of white kaolin clay had developed by schist alteration. It is notable that mica, probably muscovite coats some surfaces of the glassy quartz fragments and minor open spaces may indicate incipient, vuggy greisen development. It is postulated that originally the quartz veins developed along fractures in the country rocks.
Subsequently, the possible intrusion of a hypothetical granite body at depth provided a heat source to drive a hydrothermal system, brecciating the quartz veins. Any such granitic or other heat source was sufficiently deep so that the shale, seen at Valtreixal, is beyond the granitic metamorphic aureole. Strong hydro-fracturing and concomitant seismic activity may have created temporary weakness along the laminated shale allowing lateral migration of mineralising solutions away from the brecciated veins or other sources for a considerable distance.
The shale is relatively impervious to solution penetration across the bedding by absorbing stress and by yielding more plastically. High pressure fluids may have ruptured many of the rigid quartz veins. The country wall rock adjacent to the brecciated quartz vein is metamorphosed to sericite schist. In general the shale, based on visual and textural features, is considered to be in the low, chloritic metamorphic range.
The mineralisation at Valtreixal can be classified as a complex vein deposit. The tin mineralisation, in the form of cassiterite, is hosted by a mixture of individual veins, veinlets and vein swarms, generally with the same overall dip and dip direction. The distribution and width of veins can be quite erratic within localised areas.