A comprehensive Social and Environmental Impact Assessment (SEIA) is now mandatory for companies that strive to meet the performance standards established by the Equator Principles. These principles, agreed to by major banks, are frequently a condition of financing. Additionally, leading companies seek to meet the IFC Performance Standards on Social and Environmental Sustainability, even when financing has not been provided by the IFC. SEIAs commence with baseline studies of all the affected environmental and social components, and are informed by a fully participative public engagement process. The SEIA must comply with legislative and policy requirements and relevant international agreements and is linked to an implementable Social and Environmental Management Plant (SEMP) and closure plan. The potential for promoting sustainable development is an important factor in evaluating alternatives, and impact mitigation strategies will only be considered where avoidance of impacts is not possible. This paper outlines how these best practice requirements have guided the environmental and social impact assessment for the Trekkopje Uranium Project, located in Namib Desert near Namibia's west coast. The paper also demonstrates how a comprehensive SEIA improves a mining company's ability to manage project risks. Particular reference is made to the public participation process.