Support design of underground openings in an asphaltite mine

• First practical rock mechanics application for underground openings in asphaltite.
• The underground mine production of asphaltite is firstly projected and proposed.
• Asphaltite properties as rock material and rock mass are proposed.
• A layout for support design of underground opening in mines is proposed.
• FEM is applied to understand the suitability of support systems and support units.

A detailed study to design support systems for underground openings was carried out in this paper. Asphaltite, an energy source for thermal power plants, will be produced from the Uckardesler Asphaltite Vein in southwestern Turkey. This mine will be the first application of underground asphaltite production in the world. Two main geological formations, the Gercus formation and the Midyat formation, form the geological structure of the study area. The Gercus formation is conglomerate, sandstone, mudstone, clay, detritus, such as jibs, and the asphaltite vein located in the formation. The Midyat formation is mostly limestone. The cut and fill stoping method was selected for this mine in accordance with the geometry of the vein, topographic specifications, and expected annual production rates. Asphaltite will be excavated from the underground mine by continuous miners. The shapes and sizes of underground opening, which will include incline and ramp galleries, shafts, crosscut (X/C) galleries, main level galleries, and production galleries, were designed based on production method and rate. Rock mass classification systems and the finite element numerical method were applied to design support systems for the proposed underground openings. In this study, the engineering properties of rock masses were defined from field and laboratory studies for each formation and for asphaltite. Support systems for each underground opening were designed based on the suggestions of the rock mass rating (RMR) system and the Q system of rock mass classification. The suggested support systems were subjected to numerical analysis in order to evaluate their predicted performance. The results of the numerical modeling were analyzed to select the proper support system for each underground opening.