The area of the former copper plant lies on both banks of the River Fani in a narrow valley surrounded by high mountains and canbe divided into three sub-areas:
- The old copper mine and residual stockpile on the western bank of the river (cca approximately 2ha).
- The copper smelting plant area on the western bank of the river (cca
- The “dump site” (or “disposal area”) on the eastern side of the river (cca 4.4 ha).
Geological, hydrological and technical conditions
The main production units of the plant are partly built on the mountain slope and on a narrow plateau at an elevation of approximately 5m above the normal river level. The area is traversed by a small stream. The area between the copper production units and the river is filled out to the same elevation as the production units. The filling masses north of the small stream are defined as ‘inert’ and those to the south as slag. Slag and other wastes are deposited on more or less continuous thin alluvium overlying igneous and metamorphic rock. Up to 7m of processing wastes overly varied sands and gravels down to 10m. The dump site on the eastern side of the river is 4.4 ha area constructed on the river bed only slightly elevated above the normal river level. It was built without previous preparation of the soil or a protective lining underneath and there is also no drainage system to capture leachates.
The dumpsite is surrounded by a gravel dam of approximately 4m in height and on the eastern side a 10m high railway bank. The dam seems to be in good condition. However it is strengthened with concrete on the outside to protect it from erosion during flood periods and part of this present concrete is in bad condition due to poor concrete quality. The dump site has no lower layer protection and some 10 000m3 of slag are deposited here. The alluvium layer beneath wastes reaches the thickness of 6 to over 13m. Under this layer, there is hard peridotite bedrock at increasing depth away from the banks of the river.
In both areas, the alluvium strata form a significant aquifer on account of the large grain size and correspondingly high hydraulic conductivity. Combined with the fact that local groundwaters flow into the river predominantly through the alluvium where present, or through the slag, this suggests that any groundwater contamination would travel rapidly downstream within the aquifer, or directly into the river. In the process area, groundwater is collected by an in-built drainage system and discharged by pipe work directly into the river. In the confined disposal facility area, groundwater depths vary from 3m to 0.5m. The alluvium forms an intermediate storage medium for surface water drainage into the river, in the same way as the slag across the process area. The construction of the confined disposal facility need not influence flow through the alluvium, provided surface water inflow from the valley side is not impeded.
Since the area of the plant has been unkept for about 10 years, also the cohesion of slopes is endangered by erosion by vegetation.