The present paper deals with the foundation and operation of the Sillamae Metallurgical Plant in 1946-1989. It presents data on uranium production from the local Dictyonema shale as well as from the imported ore. Data on the processing of enriched uranium are also given. The article describes the work of the Narva pilot plant and construction of the waste depository in Sillamae, which is an environmental hazard. The pre-investment planning of the initial remedial measures is presented.