Is there anyone selling mineral water in Hulunbuir Prairie?

Yes. According to the search on Baidu Map, there are supermarkets in Hulunbuir Prairie, Beierxin Luyuan Grassland Specialty Supermarket in Hailar District, China Resources Vanguard Grassland Specialty Supermarket, etc. all sell mineral water. Hulunbuir Grassland is located in the northeastern part of the Inner Mongolia Autonomous Region, on the Hulunbuir Plateau to the west of the Greater Khingan Mountains. It is named after Hulun Lake and Bell Lake.