The Department of Culture, Sports and Tourism of Thanh Hoa province has sent a document to the Chairman of the Provincial People's Committee to assign the Department of Natural Resources and Environment to advise on procedures to put Dun Mountain (Ha Long commune, Ha Trung district) into an area temporarily banned from mineral activities.

The Department of Historical Science of Thanh Hoa presided over and coordinated with the People's Committee of Ha Trung district, the Center for Historical Research and Cultural Heritage Conservation and related units to organize a scientific workshop to evaluate the location, historical and cultural values, and regional connections of Dun mountain in the space of the national relic of Trieu Tuong Temple and Nguyen Dynasty relics.

Previously, the Department of Culture, Sports and Tourism of Thanh Hoa coordinated with relevant units to organize a conference to survey and evaluate the scale, value, historical, cultural, heritage and tourism significance of the caves at Dun Mountain.

The results of the actual survey and conference organization show that Dun mountain has a scale and area of ​​about 6.5 hectares, located in the planning for exploration and exploitation of minerals for common construction materials.

Inside the mountain, there is a large cave with 4 connecting doors. This cave has many natural stalactites with interesting shapes, an underground water source flowing into the provincial relic Ben Quan Lake, with great potential for tourism development.

At the time of the survey, authorities discovered that the cave floor area in Dun Mountain had a number of ceramic household relics of historical date (archaeological traces) that needed further research.

Surveys by historical researchers also show that Dun Mountain has a close connection, located in the space of Trieu Tuong Mountain area - where the national relic Trieu Tuong Mausoleum is located.

The cave at Dun Mountain was discovered by local people a long time ago. This used to be a shelter for people during the two resistance wars against France and the US, and was a source of water for irrigation for the people of three villages: Nghia Dung, Khac Dung and Gia Mieu (Ha Long commune).