Russian cement producer Eurocement plans to build a US $100m cement plant in the Krasnoyarsk Region, Anatoly Tikhonov, deputy governor of the region, said Tuesday.   The annual production capacity of the plant is projected at 500,000t, Tikhonov said.   Eurocement is currently choosing the construction site for the plant and plans to make a final decision on the site in 2007, Tikhonov said.