Blasting is one of the most important operations in underground coal mine development, especially during the driving of roadways and galleries. The main objective of blasting is to fragment coal efficiently so that it can be easily loaded and transported. In underground coal mines, development galleries are usually driven within specified dimensional limits for safety and roof stability. In bord and pillar workings, development galleries are generally driven within widths ranging from 4.2 to 4.8 m depending on seam conditions and support requirements. The present case study was conducted in a gallery of 4.2 m width and 3.0 m height, which helps maintain roof stability and proper support installation.

These dimensional restrictions significantly influence the design of drilling and blasting patterns. If blasting parameters are not properly designed within these limited gallery dimensions, it may lead to oversized coal fragments, excessive fines, poor advance of the face, and damage to the roof and side walls of the gallery.

This study investigates the blasting parameters that influence coal fragmentation in underground coal mine development headings. Important parameters such as burden, spacing, hole depth, powder factor, charge distribution, and delay timing are analyzed. The study particularly examines the effectiveness of an improved wedge cut blasting pattern in rectangular development galleries.

Field observations and analysis show that proper design of wedge cut holes provides an initial free face that improves fragmentation and enhances the efficiency of subsequent blasting holes. Optimizing blasting parameters and modifying the wedge cut pattern can significantly improve advance per round, reduce fines generation, and minimize secondary blasting.

The results of this study provide guidelines for designing efficient blasting patterns for underground coal mine development under restricted gallery dimensions. Improved blast design can enhance productivity, reduce operational costs, and improve safety in underground coal mining operations.