URANIUM MINE DEVELOPMENT IN MONGOLIA

摘要

Most of the known uranium deposits in Mongolia are related to volcano-tectonic structure of Late Mesozoic and permeable sandstone aquifers of terrigenous sedimentary rocks in Late Mesozoic-Cenozoic basin. A young surficial uranium deposit was recently discovered in Quaternary alluvial sediments. Uranium deposits were classified according to the IAEA classification scheme. Besides supergene and hydrothermal uranium discoveries, uranium mineralization is also found in Lower Cretaceous lignite seams, in the Mesozoic alkaline intrusive related REE, Th-, U and in metasomatic rocks, migmatites, pegmatites localized in Precambrian metamorphic rocks. Currently, no uranium is being produced in Mongolia though the pilot testing has been done. Pilot testing was carried out for the Khairhan and Kharaat deposits in Mongolia and these have been shown to be amenable to acid leach (sulphuric acid) with the addition of an oxidizing agent. These tests confirmed that hydraulic control can be maintained and that the uranium solubilization and mobilization can be controlled. The results of the test were encouraging, with the well production rate, uranium concentration in produced solutions, chemical usage, and estimated uranium recovery all within ranges expected for normal commercial operations. However, a number of deposits are in the stage of mine development. The Government of Mongolia has approved the Agreement for mine development of the Zuuvch ovoo and Dulaan uul deposits. Pilot testing on these deposits are underway and uranium will be soon be extracted by in-situ leaching.