A Unique Mining Method Minimizes Environmental Impact
U3O8 Corp.’s Laguna Salada Deposit in Argentina consists of soft gravel with uranium-vanadium concentrated in the fine material located between the pebbles from surface down to a depth of 3 metres. The soft gravel affords us the opportunity of mining using a “migrating trench” in which environmental restoration would be done in real time at the same rate as the mining. Our aim is that at the end of the mine’s life, there would be very little evidence that the gravel plain had been mined. Conventional underground mining would be used at the Berlin Deposit in Colombia.
The mining method that was modelled in the Preliminary Economic Assessment of the Laguna Salada Deposit in Argentina is a long, narrow trench that would be excavated in the flat gravel plain with equipment that is very similar to road-building machinery. The trench would then migrate sideways with gravel from the leading edge of the trench being washed with water and screened to remove the pebbles and coarse sand from the very fine-grained material that would contain most of the gravel’s uranium and vanadium. The washed gravel would then be immediately replaced on the trailing edge of the trench and the shrubby vegetation removed immediately prior to mining at the leading edge would be replanted in the freshly replaced gravel on the trailing edge.
The very finest component of the gravel would be mixed with more water and pumped to a central processing facility for the removal of uranium and vanadium. This real-time environmental restoration means that whether one were to visit the mine on day one or in year ten of its life, one would simply see a trench with removal of desert shrubs on its leading edge and replanting on its back edge. We are also investigating the business case for providing a proportion of Laguna Salada’s power from wind turbines, since the Patagonian region has some of the best wind resources in the world.
The Preliminary Economic Assessment on the Berlin Deposit in Colombia modelled an underground operation in which the steeply inclined parts of the deposit would be mined by cut and fill methods (illustrated below) and the flat parts of the deposit by room and pillar methods (illustrated below). Once the uranium-bearing rock is removed and processed, it would be mixed with cement and replaced in the underground excavations to provide support for the mine and also to minimize the environmental footprint of the mine.