**Acknowledgements**

The authors are grateful to the Ministry of Electronics and Information Technology, Government of India, for financial support to develop the surveillance system (Grant No. 13(2)/2013-CC&BT). They are also immensely indebted to the General Manager and other concerned officials of North Eastern Coalfields, Margherita, Assam, India to provide the necessary data, extend logistic support, and permit field experimentation of the developed system at Tirap Opencast Coal Mine. The authors are also thankful to the Director, CSIR-Central Institute of Mining and Fuel Research, Dhanbad, India, for his valuable guidance.
