SOFIA (Reuters) – German construction materials group Knauf will invest -62 million ($84 million) in a new plasterboard plant in southern Bulgaria, the company said yesterday. The new plant, to be built in the Maritsa East mine and thermal power complex, will have an annual capacity of 30 million square meters and will begin operations next October, said Stefan Vassilev, project manager for the Bulgarian unit. «We decided to invest because of Bulgaria’s accession to the European Union and the construction boom in the country,» he said. The plant will use gypsum waste from the desulfurization process in the two thermal power plants that operate in the Maritsa East complex. This is Knauf’s second building materials plant in Bulgaria after it acquired 60 percent of Bulgarian Gipsfazer in 1997 and has gradually increased its stake since then. More than 30 percent of Bulgaria’s record-high -4.0 billion in foreign direct investment last year went on construction and property deals.