Induced seismic force reduction using air deck blasting at Mae Moh Mine, Thailand

Abstract

Mae Moh mine is one of the deepest open pit mines in Southeast Asia, currently 300 m below the ground surface. According to its master mine plan, the mine depth will be approximately 500 m by year 2028. It is located in Lampang, 650 km north of Bangkok. Recently, it produced approximately 15 million tons of lignite and over 90 million m3 of waste a year to serve ten lignite-fired power plants, with total capacity of 2,400 MW. The mine and power plants are operated by a prominent Thai state enterprise, Electricity Generating Authority of Thailand (EGAT). To remove such a huge amount of dense Overburden and Interburden claystone, drill and blasting techniques have been utilized. The overburden and interburden are fractured and loosen by blasting suitable for the production and also to reduce fuel consumption and wear rate of excavators as well. There is, however, a major unwanted consequence of the blasting technique which is induced seismic force. The induced seismic force would potentially cause environmental impacts. To increase safety of the working environment and contribute to the social responsibility, the mine has lately replaced the conventional blasting technique with air deck blasting. With less amount of explosive usage, the air deck blasting results in less ground vibration with satisfied mine production. The measured peak particle velocity, related to the induced seismic force and the ground vibration, was reduced by 32-69%. Surprisingly, the air deck length recommended at 20% of the explosive charge can reduce the induced seismic force while increasing fragmentation and higher productivity. Copyright 2013 ARMA, American Rock Mechanics Association.