In this paper, some examples of damages and property loss caused by mining activities, as well as an example of avoiding the possible damage in Yunnan Province of China, are presented. It is shown that in mountain regions, the influence areas of caving and subsidence produced by mining may be greatly enlarged and the loss of life and property can be serious. So there is a need to be very careful in choosing the construction sites when planning the surface structures of a mine at mountain regions.
Yunnan Province is located in the southwest of China and is at the main part of the Yunnan- Guizhou plateau. In this province, the mountain area occupies over 90% of the land. The altitude is usually between 1000 to 2000 meters above sea level and many mountains are higher than 3000m. The production of the non- ferrous metals was one of the important industries in the history of the Province. During Han Dynasty (B. C. 206 - A. D. 220), Yunnan was famous in China for its silver production. Since Ming Dynasty (A.D.1368 - A.D.1644), Gejiu has been the most important region in tin production. Today, there are still a lot of tin mines in Gejiu, and Yunnan Tin Corporation is the most important mining enterprise in the region. Copper is also one of the principal metals produced in the province. In Yunnan province, transportation has always been an obstacle to the economical development and the conditions are even worse for the mines. Because of the problem, the mine employees had to go to work on foot during many years. The living houses as well as the Workshops were then constructed usually near the mining entrances. For some of the mines, the Condition is still similar today. It is well known that surface subsidence and caving can be produced by underground mining, surface buildings should then be located outside of the possible caving area. In plain regions, it is easy to choose the building sites. In mountain regions, however, the buildings may be constructed near the caving area. The experiences from many mines of Yunnan Province show that when underground mining is conducted at mountain regions, surface caving and rock failure may happen easily. The failed rocks may roll down the hill and threat the safety of people and structures. The first lesson produced by underground mining came from the Malage Tin Mine. This is a mine under Yunnan Tin Corporation and has been established for several decades. In 1958, one macro crack was found at the surface near the houses where workers and staffs lived, although that was an area outside the possible caving region. All of the houses there were then abandoned soon. It was found later that this was a wrong decision and without data support. Because the crack keeps the same state and no new crack was found long time after that, all houses and buildings stand well 3 decades later.