FREETOWN, Sierra Leone — The government has begun burying the 350 people killed earlier this week in mudslides in Sierra Leone’s capital, and it warned Thursday of new danger from a large crack that has opened on a mountainside where residents were told to evacuate. Another 600 people remained missing from the mudslides and flooding early Monday, as workers sought to recover more bodies from the thick mud and debris of smashed homes. The government hired 600 gravediggers for the burials, which are taking place in a cemetery where victims of the 2014-15 Ebola outbreak that killed thousands in the West African nation were laid to rest.