The clues in the instance point toward a past accident at the Tian Tian Le Mine, and those connected to Soran—aside from her father's accident—are people she's able to reach in Tingting Flower Town. Some of these people's families underwent changes also linked to Tian Tian Le, and the "Ember Girl" likely comes from inside this very network of relationships.
The most important, naturally, is Soran's father's accident. The number of people who died in the collapsed mine may not be as high as Tian Tian Le claimed. There are rarely women working the mines, and young women even less so, so the only option is to start with the victims' relatives.
