Here’s an overview of drilling and blasting in coal mining:
Drilling Operations
Purpose and Types of Drilling:
Exploration Drilling: Initially used to determine the extent and quality of coal deposits. Core drilling and rotary drilling are common methods to extract samples for geological analysis.
Production Drilling: Once coal reserves are confirmed, production drilling creates boreholes for explosives placement to fragment the coal for extraction.
Drill Types and Equipment:
Rotary Drills: Commonly used for production drilling in both surface and underground mining. These drills use rotating drill bits to bore into rock formations.
Longhole Drills: Used in underground mining for drilling horizontal or inclined blast holes in ore and coal seams.
Drilling Techniques:
Vertical and Inclined Drilling: Depending on the coal seam’s depth and angle, drills can be positioned vertically or at an angle to access the coal.
Pattern and Hole Layout: Engineers design drilling patterns to ensure efficient blasting and coal recovery, considering factors such as seam thickness, overburden stability, and safety.
Blasting Operations
Purpose and Process:
Fragmentation: Blasting breaks up the coal into manageable pieces for excavation and processing.
Safety and Efficiency: Controlled explosions are essential to ensure worker safety, minimize environmental impact (such as ground vibrations and air overpressure), and optimize coal yield.
Types of Explosives:
Bulk Explosives: Typically used for large-scale surface mining operations where high-energy explosives are needed to fragment rock and coal efficiently.
Cartridge Explosives: Used in underground mining for precise blasting in confined spaces, offering more controlled fragmentation.
Blast Design and Execution:
Blast Plans: Detailed plans specify hole depths, explosive types and quantities, initiation sequences, and safety precautions.
Initiation Systems: Electronic detonators and blasting caps ensure precise timing and control over the explosion sequence, enhancing safety and operational efficiency.
