19 NexGen Technologies for Mining and Fuel Industries ISBN 978-93-85926-40-2 Status of import substitute potash reserves and innovative technology for deep seated mining in India J.K. Mohnot 1 and P.K. Singh 2 1 Geotechnical Engineering and Underground Space, CSIR-Central Institute of Mining and Fuel Research, Research Centre, Roorkee–247667, India 2 CSIR-Central Institute of Mining and Fuel Research, Dhanabad, Jharkhand, India ABSTRACT: The fertiliser mineral potash is completely imported in India. But, it has been identified the deep seated vast reserves of potash mineralisation in Nagaur-Ganganagar basin in Northwest part of the Rajasthan state about three decades ago. The current requirement and the technology encourages for its mining after detailed exploration with estimation of in-situ grades for atleast one of the prospective locations in Kalu, Jaitpura, Satipura, Bharusari and Lakhasar sub- basins. The source of potash has also been found in Glauconite deposits at surface to sub-surface locations in various states of India. These deposits are still not taken up for the mining. This paper is an attempt to highlight the international status of potash and the latest emerging opportunities for its mining in India as an import substitute mineral with details of innovative techno-economic mining technology including solution mining technique for deep seated potassium deposits. 1. INTRODUCTION he entire requirement of potash in India is met by imports since there is no commer- cial production in the country as described by the author Mohnot. [1] The potash is mainly used as fertiliser and other uses of potassium minerals are in the manufacturing of glass, explosives and chemicals. The current import of potash during the year 2014–15 is around 4.6 million tonne which entails US$ 1400 million (i.e., approx. ` 100,000 million/annum) as per Indian Minerals Year Book [2] and projected more in future if no indigenous production comes up. Thus, there exists huge investment opportunities for potash mining in India as an import substitute mineral. Potassium fertilisers constitute an important variety amongst the fertilisers used for plants. There is no substitute for natural potassium fertilisers. The most prevalent form in use is muriate of potash (KCl), normally called potash (Potash related terminology are described in Appendix-I). However, potassium sulphate (K 2 SO 4 ) is also used as fertiliser under special soil conditions for certain types of plants. Most of the potash is obtained by underground mining of bedded deposits of potassium chloride and sulphate associated with thick halite (NaCl) bearing evaporite beds. The highly concentrated brines of some of the saline lakes are among other sources. Some igneous and sedimentary rocks have higher concentration of potash in silicate form which is not easily soluble and, therefore, cannot be used up by the plants. The most important source of potash hence remains to be the bedded deposits associated with halite- bearing evaporite sequences as reported by GSI. [3] In north-west Rajasthan, halite belts are developed in the Lower Palaeozoic evaporite sequence. So far, about 6 trillion tonne halite containing about 80% NaCl has been estimated by Geological Survey of India (GSI) over an area of 40,000 sq. km in Nagaur-Ganganagar T