Arising issues and approaches to classify the hydrogeological types and complexity ranks of a complicated coal mine in China

Practical classification of the mining hydrogeological types in coal mines is a fundamental job and prerequi- site for coal mines to effectively prevent various kinds of mine water hazards. The Directive of Coal Mines to Prevent & Control Mine Water Hazards (enacted in 2009) regulated that coal mines in China must re-categorize its mining hydro- geological types and complexity ranks every three years. The latest round of national-wide classification of hydrogeolog- ical types of coal mines in 2013 revealed the problems of simply piling existent geologic exploration data and hardly encompassing the varied features of a complicated coal mine in an as-a-whole classification. There is an urgent need to highlight the mining-plan-oriented classifying principles and methods. Fangezhuang Coal Mine of Kailuan Group (Chi- na),which had shocked the world for its gigantic karst-sinkhole water inrush accident in 1984,is typical of long-min- ing-history,deep-mined and geologically complicated active coal mines in East China. It is difficult to use traditional classifying methods to encompass the wide range of hydrogeological features of Fangezhuang Mine into an overall hydrogeological type. Based on its mining horizon and panel subdivisions,the paper classified the Fangezhang into dif- ferent sub-regions of mining hydrogeological types and ranked the complexity of the sub-regions respectively. The paper presents that the mining hydrogeological types and complexity ranks of a coal mine should objectively correspond with its current mining and hydrogeological status. It is concluded that the classifying practice for a complicated coal mine should definitely observe the mining-plan-oriented classifying principles and objectively divide the coal mine into dif- ferent sub-regions and assess the mining hydrogeological type and complexity rank of each sub-region instead.