Impact of the mechanical characteristics of weak rocks and trona ore beds on the main drift deformation at the beypazari mine, Turkey

In northern Turkey, the Main Drift, T-2000, and a roadway, T-3000, were excavated for Beypazari trona (natural soda) underground mine project between the years 1999 and 2001. This work was one of the most important mining projects in Turkey in the last decade. T-2000 was designed as a main drift with a length of 965m, 14° inclined and excavated with a cross-sectional area of 18m2. The T-3000 roadway was driven in the trona beds for the first production panel. In this study, in situ and laboratory studies have been made to define the formations through which the drift has been driven. In situ engineering geology measurements were carried out consisting of field observation, mapping, boreholes and laboratory tests on samples collected from the trona field and the boreholes. After drift excavation and support installation, the deformations and the loads on the supports were measured. As a result of this study, the deformational characteristics of the trona ore beds and weak rocks and their effect on the main drift (T-2000) deformation have been determined. The importance of this study lies in the fact that most natural soda mines in the world apply room and pillar mining methods. This study is probably the first investigation on underground openings with steel-set support systems and rock deformations in natural soda beds.