A discussion on water inrush coefficient

Water inrush from coal seam floor is a kind of natural disaster during coal mining process in Northern China coal field.The main method for predicting water inrush from coal seam floor and evaluating the water inrush degree of coal mining with water pressure is water inrush coefficient method.However,calculation and determination of critical values of water inrush coefficient need to be studied further.Based on explaining coal mining with water pressure and water inrush coefficient,several formulas for calculating water inrush coefficient and determination methods of parameters were discussed,the origination and application condition of critical water inrush coefficient and a new formula of calculating water inrush coefficient were presented.Not only water pressure and aquiclude thickness but also fracture depth of coal seam floor,intrusion height and top aquiclude part in Ordovician limestone were considered in the formula which laid the foundation for calculating new critical value of water inrush coefficient.