Meghalaya High Court appointed National Green Tribunal (NGT) judge, justice B P Katakey, who is on a fact finding mission to expose illegal rat hole coal mining in the Garo Hills, has said that the huge number of illegal coke factories, which mushroomed in the West Khasi Hills, bordering South and East Garo Hills, and East Khasi Hills districts, was made possible due to the availability of coal that was being mined illegally in the region for a long time.