A dust explosion in an underground coal mine consists of two explosions, namely a primary explosion and a secondary explosion. The primary explosion usually occurs in methane gas, causing waves along the air way and the dispersion of dust. The second explosion occurs due to the concentration of coal dust and methane in the explosive range and is triggered by first explosion. This research was conducted to analyse how the two-stage coal dust explosion process occurs in underground mining by indirect measurement, specifically video and image processing. The purpose of the study is to analyse the effect of methane gas and dust concentration on dust explosibility, characterized by flame speed and flame length. Travel time is obtained from video processing, while distance is obtained from image processing. The experiment was carried out in three conditions: varying methane gas concentrations, varying coal dust concentrations and different positions and areas of coal dust. The experiments lead to the following conclusions. (1) Increased methane concentration will increase the flame speed of a coal dust explosion. In this experiment, the flame speed increased from 1.5 to 2 times the initial condition (methane with concentration 5-6 percent). (2) An increase in dust concentration will increase the flame distance by 1.5 to 2 times compared to without the presence of dust. (3) Coal dust with initial concentrations below lower explosive limit (LEL) will be dangerous and can explode when the dust is mixed with methane gas. This condition often occurs in mine explosions, (4) dust which initially in low concentrations can cause fatalities, the explosibility of coal dust will be higher if it is spread over a wider area and positioned close to the explosion of methane gas. CITATION:Ihsan, A, Priagung Widodo, N, Sulistianto, B and Agung Prata, D, 2019. Analysis of methane and coal dust explosion at two stage process using video and image processing, in Proceedings Australian Mine Ventilation Conference 2019, pp 319329 (The Australasian Institute of Mining and Metallurgy: Melbourne).