Development of a Fuzzy Classification System to Evaluate the Quality of Coal Mines Roof (Case Study: Eastern Alborz Coal Mines)

The longwall method is the most commonly method used in extraction of coal layers. The mining review records shows that the majority of the dangers of coal underground mines related to the sudden and uncontrolled roof fall-out of the stopes. Predicting the behavior and the ability to destroy the roof rock is very important for the successful execution of longwall method and reducing its risks. In this study, we will present a new fuzzy classification system by using the theory of fuzzy sets and fuzzy multi-criteria approach to evaluate the roof quality of the coal mines. 

In the first step, 8 parameters were selected as effective factors in the classification system. This selection was performed after reviewing the parameters affecting the roof quality of coal mines. The parameters include: Uniaxial Compressive Strength (UCS), Brazilian Tensile Strength (BTS), moisture sensitivity, spacing and continuity of discontinuities, thickness of layers, joints slope and difference of stopes’ and critical joints’ orientation.
 

Fuzzy classification system was presented after determining the parameters weight. The fuzzy classification system can evaluate and categorize the roof quality of coal mines. The classification qualitatively classified the quality of roofs in 3 classes (good, fair and poor). 

In order to evaluate the performance of the fuzzy classification system data of to 15 stopes in Eastern Alborz coal mines were evaluated. The results of this study showed that we can evaluate the quality of the roof rock with fuzzy classification system with high reliability in for coal mines roofs.